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dt_link.c (256281) dt_link.c (260670)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident "%Z%%M% %I% %E% SMI"
28
29#define ELF_TARGET_ALL
30#include <elf.h>
31
32#include <sys/types.h>
33#if defined(sun)
34#include <sys/sysmacros.h>
35#else
36#define P2ROUNDUP(x, align) (-(-(x) & -(align)))
37#endif
38
39#include <unistd.h>
40#include <strings.h>
41#if defined(sun)
42#include <alloca.h>
43#endif
44#include <limits.h>
45#include <stddef.h>
46#include <stdlib.h>
47#include <stdio.h>
48#include <fcntl.h>
49#include <errno.h>
50#if defined(sun)
51#include <wait.h>
52#else
53#include <sys/wait.h>
54#include <libelf.h>
55#include <gelf.h>
56#include <sys/mman.h>
57#endif
58#include <assert.h>
59#include <sys/ipc.h>
60
61#include <dt_impl.h>
62#include <dt_provider.h>
63#include <dt_program.h>
64#include <dt_string.h>
65
66#define ESHDR_NULL 0
67#define ESHDR_SHSTRTAB 1
68#define ESHDR_DOF 2
69#define ESHDR_STRTAB 3
70#define ESHDR_SYMTAB 4
71#define ESHDR_REL 5
72#define ESHDR_NUM 6
73
74#define PWRITE_SCN(index, data) \
75 (lseek64(fd, (off64_t)elf_file.shdr[(index)].sh_offset, SEEK_SET) != \
76 (off64_t)elf_file.shdr[(index)].sh_offset || \
77 dt_write(dtp, fd, (data), elf_file.shdr[(index)].sh_size) != \
78 elf_file.shdr[(index)].sh_size)
79
80static const char DTRACE_SHSTRTAB32[] = "\0"
81".shstrtab\0" /* 1 */
82".SUNW_dof\0" /* 11 */
83".strtab\0" /* 21 */
84".symtab\0" /* 29 */
85#ifdef __sparc
86".rela.SUNW_dof"; /* 37 */
87#else
88".rel.SUNW_dof"; /* 37 */
89#endif
90
91static const char DTRACE_SHSTRTAB64[] = "\0"
92".shstrtab\0" /* 1 */
93".SUNW_dof\0" /* 11 */
94".strtab\0" /* 21 */
95".symtab\0" /* 29 */
96".rela.SUNW_dof"; /* 37 */
97
98static const char DOFSTR[] = "__SUNW_dof";
99static const char DOFLAZYSTR[] = "___SUNW_dof";
100
101typedef struct dt_link_pair {
102 struct dt_link_pair *dlp_next; /* next pair in linked list */
103 void *dlp_str; /* buffer for string table */
104 void *dlp_sym; /* buffer for symbol table */
105} dt_link_pair_t;
106
107typedef struct dof_elf32 {
108 uint32_t de_nrel; /* relocation count */
109#ifdef __sparc
110 Elf32_Rela *de_rel; /* array of relocations for sparc */
111#else
112 Elf32_Rel *de_rel; /* array of relocations for x86 */
113#endif
114 uint32_t de_nsym; /* symbol count */
115 Elf32_Sym *de_sym; /* array of symbols */
116 uint32_t de_strlen; /* size of of string table */
117 char *de_strtab; /* string table */
118 uint32_t de_global; /* index of the first global symbol */
119} dof_elf32_t;
120
121static int
122prepare_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf32_t *dep)
123{
124 dof_sec_t *dofs, *s;
125 dof_relohdr_t *dofrh;
126 dof_relodesc_t *dofr;
127 char *strtab;
128 int i, j, nrel;
129 size_t strtabsz = 1;
130 uint32_t count = 0;
131 size_t base;
132 Elf32_Sym *sym;
133#ifdef __sparc
134 Elf32_Rela *rel;
135#else
136 Elf32_Rel *rel;
137#endif
138
139 /*LINTED*/
140 dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff);
141
142 /*
143 * First compute the size of the string table and the number of
144 * relocations present in the DOF.
145 */
146 for (i = 0; i < dof->dofh_secnum; i++) {
147 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
148 continue;
149
150 /*LINTED*/
151 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
152
153 s = &dofs[dofrh->dofr_strtab];
154 strtab = (char *)dof + s->dofs_offset;
155 assert(strtab[0] == '\0');
156 strtabsz += s->dofs_size - 1;
157
158 s = &dofs[dofrh->dofr_relsec];
159 /*LINTED*/
160 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
161 count += s->dofs_size / s->dofs_entsize;
162 }
163
164 dep->de_strlen = strtabsz;
165 dep->de_nrel = count;
166 dep->de_nsym = count + 1; /* the first symbol is always null */
167
168 if (dtp->dt_lazyload) {
169 dep->de_strlen += sizeof (DOFLAZYSTR);
170 dep->de_nsym++;
171 } else {
172 dep->de_strlen += sizeof (DOFSTR);
173 dep->de_nsym++;
174 }
175
176 if ((dep->de_rel = calloc(dep->de_nrel,
177 sizeof (dep->de_rel[0]))) == NULL) {
178 return (dt_set_errno(dtp, EDT_NOMEM));
179 }
180
181 if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf32_Sym))) == NULL) {
182 free(dep->de_rel);
183 return (dt_set_errno(dtp, EDT_NOMEM));
184 }
185
186 if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) {
187 free(dep->de_rel);
188 free(dep->de_sym);
189 return (dt_set_errno(dtp, EDT_NOMEM));
190 }
191
192 count = 0;
193 strtabsz = 1;
194 dep->de_strtab[0] = '\0';
195 rel = dep->de_rel;
196 sym = dep->de_sym;
197 dep->de_global = 1;
198
199 /*
200 * The first symbol table entry must be zeroed and is always ignored.
201 */
202 bzero(sym, sizeof (Elf32_Sym));
203 sym++;
204
205 /*
206 * Take a second pass through the DOF sections filling in the
207 * memory we allocated.
208 */
209 for (i = 0; i < dof->dofh_secnum; i++) {
210 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
211 continue;
212
213 /*LINTED*/
214 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
215
216 s = &dofs[dofrh->dofr_strtab];
217 strtab = (char *)dof + s->dofs_offset;
218 bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size);
219 base = strtabsz;
220 strtabsz += s->dofs_size - 1;
221
222 s = &dofs[dofrh->dofr_relsec];
223 /*LINTED*/
224 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
225 nrel = s->dofs_size / s->dofs_entsize;
226
227 s = &dofs[dofrh->dofr_tgtsec];
228
229 for (j = 0; j < nrel; j++) {
230#if defined(__arm__)
231/* XXX */
232printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
233#elif defined(__ia64__)
234/* XXX */
235printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
236#elif defined(__i386) || defined(__amd64)
237 rel->r_offset = s->dofs_offset +
238 dofr[j].dofr_offset;
239 rel->r_info = ELF32_R_INFO(count + dep->de_global,
240 R_386_32);
241#elif defined(__mips__)
242/* XXX */
243printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
244#elif defined(__powerpc__)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident "%Z%%M% %I% %E% SMI"
28
29#define ELF_TARGET_ALL
30#include <elf.h>
31
32#include <sys/types.h>
33#if defined(sun)
34#include <sys/sysmacros.h>
35#else
36#define P2ROUNDUP(x, align) (-(-(x) & -(align)))
37#endif
38
39#include <unistd.h>
40#include <strings.h>
41#if defined(sun)
42#include <alloca.h>
43#endif
44#include <limits.h>
45#include <stddef.h>
46#include <stdlib.h>
47#include <stdio.h>
48#include <fcntl.h>
49#include <errno.h>
50#if defined(sun)
51#include <wait.h>
52#else
53#include <sys/wait.h>
54#include <libelf.h>
55#include <gelf.h>
56#include <sys/mman.h>
57#endif
58#include <assert.h>
59#include <sys/ipc.h>
60
61#include <dt_impl.h>
62#include <dt_provider.h>
63#include <dt_program.h>
64#include <dt_string.h>
65
66#define ESHDR_NULL 0
67#define ESHDR_SHSTRTAB 1
68#define ESHDR_DOF 2
69#define ESHDR_STRTAB 3
70#define ESHDR_SYMTAB 4
71#define ESHDR_REL 5
72#define ESHDR_NUM 6
73
74#define PWRITE_SCN(index, data) \
75 (lseek64(fd, (off64_t)elf_file.shdr[(index)].sh_offset, SEEK_SET) != \
76 (off64_t)elf_file.shdr[(index)].sh_offset || \
77 dt_write(dtp, fd, (data), elf_file.shdr[(index)].sh_size) != \
78 elf_file.shdr[(index)].sh_size)
79
80static const char DTRACE_SHSTRTAB32[] = "\0"
81".shstrtab\0" /* 1 */
82".SUNW_dof\0" /* 11 */
83".strtab\0" /* 21 */
84".symtab\0" /* 29 */
85#ifdef __sparc
86".rela.SUNW_dof"; /* 37 */
87#else
88".rel.SUNW_dof"; /* 37 */
89#endif
90
91static const char DTRACE_SHSTRTAB64[] = "\0"
92".shstrtab\0" /* 1 */
93".SUNW_dof\0" /* 11 */
94".strtab\0" /* 21 */
95".symtab\0" /* 29 */
96".rela.SUNW_dof"; /* 37 */
97
98static const char DOFSTR[] = "__SUNW_dof";
99static const char DOFLAZYSTR[] = "___SUNW_dof";
100
101typedef struct dt_link_pair {
102 struct dt_link_pair *dlp_next; /* next pair in linked list */
103 void *dlp_str; /* buffer for string table */
104 void *dlp_sym; /* buffer for symbol table */
105} dt_link_pair_t;
106
107typedef struct dof_elf32 {
108 uint32_t de_nrel; /* relocation count */
109#ifdef __sparc
110 Elf32_Rela *de_rel; /* array of relocations for sparc */
111#else
112 Elf32_Rel *de_rel; /* array of relocations for x86 */
113#endif
114 uint32_t de_nsym; /* symbol count */
115 Elf32_Sym *de_sym; /* array of symbols */
116 uint32_t de_strlen; /* size of of string table */
117 char *de_strtab; /* string table */
118 uint32_t de_global; /* index of the first global symbol */
119} dof_elf32_t;
120
121static int
122prepare_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf32_t *dep)
123{
124 dof_sec_t *dofs, *s;
125 dof_relohdr_t *dofrh;
126 dof_relodesc_t *dofr;
127 char *strtab;
128 int i, j, nrel;
129 size_t strtabsz = 1;
130 uint32_t count = 0;
131 size_t base;
132 Elf32_Sym *sym;
133#ifdef __sparc
134 Elf32_Rela *rel;
135#else
136 Elf32_Rel *rel;
137#endif
138
139 /*LINTED*/
140 dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff);
141
142 /*
143 * First compute the size of the string table and the number of
144 * relocations present in the DOF.
145 */
146 for (i = 0; i < dof->dofh_secnum; i++) {
147 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
148 continue;
149
150 /*LINTED*/
151 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
152
153 s = &dofs[dofrh->dofr_strtab];
154 strtab = (char *)dof + s->dofs_offset;
155 assert(strtab[0] == '\0');
156 strtabsz += s->dofs_size - 1;
157
158 s = &dofs[dofrh->dofr_relsec];
159 /*LINTED*/
160 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
161 count += s->dofs_size / s->dofs_entsize;
162 }
163
164 dep->de_strlen = strtabsz;
165 dep->de_nrel = count;
166 dep->de_nsym = count + 1; /* the first symbol is always null */
167
168 if (dtp->dt_lazyload) {
169 dep->de_strlen += sizeof (DOFLAZYSTR);
170 dep->de_nsym++;
171 } else {
172 dep->de_strlen += sizeof (DOFSTR);
173 dep->de_nsym++;
174 }
175
176 if ((dep->de_rel = calloc(dep->de_nrel,
177 sizeof (dep->de_rel[0]))) == NULL) {
178 return (dt_set_errno(dtp, EDT_NOMEM));
179 }
180
181 if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf32_Sym))) == NULL) {
182 free(dep->de_rel);
183 return (dt_set_errno(dtp, EDT_NOMEM));
184 }
185
186 if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) {
187 free(dep->de_rel);
188 free(dep->de_sym);
189 return (dt_set_errno(dtp, EDT_NOMEM));
190 }
191
192 count = 0;
193 strtabsz = 1;
194 dep->de_strtab[0] = '\0';
195 rel = dep->de_rel;
196 sym = dep->de_sym;
197 dep->de_global = 1;
198
199 /*
200 * The first symbol table entry must be zeroed and is always ignored.
201 */
202 bzero(sym, sizeof (Elf32_Sym));
203 sym++;
204
205 /*
206 * Take a second pass through the DOF sections filling in the
207 * memory we allocated.
208 */
209 for (i = 0; i < dof->dofh_secnum; i++) {
210 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
211 continue;
212
213 /*LINTED*/
214 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
215
216 s = &dofs[dofrh->dofr_strtab];
217 strtab = (char *)dof + s->dofs_offset;
218 bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size);
219 base = strtabsz;
220 strtabsz += s->dofs_size - 1;
221
222 s = &dofs[dofrh->dofr_relsec];
223 /*LINTED*/
224 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
225 nrel = s->dofs_size / s->dofs_entsize;
226
227 s = &dofs[dofrh->dofr_tgtsec];
228
229 for (j = 0; j < nrel; j++) {
230#if defined(__arm__)
231/* XXX */
232printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
233#elif defined(__ia64__)
234/* XXX */
235printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
236#elif defined(__i386) || defined(__amd64)
237 rel->r_offset = s->dofs_offset +
238 dofr[j].dofr_offset;
239 rel->r_info = ELF32_R_INFO(count + dep->de_global,
240 R_386_32);
241#elif defined(__mips__)
242/* XXX */
243printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
244#elif defined(__powerpc__)
245/* XXX */
246printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
245 /*
246 * Add 4 bytes to hit the low half of this 64-bit
247 * big-endian address.
248 */
249 rel->r_offset = s->dofs_offset +
250 dofr[j].dofr_offset + 4;
251 rel->r_info = ELF32_R_INFO(count + dep->de_global,
252 R_PPC_REL32);
247#elif defined(__sparc)
248 /*
249 * Add 4 bytes to hit the low half of this 64-bit
250 * big-endian address.
251 */
252 rel->r_offset = s->dofs_offset +
253 dofr[j].dofr_offset + 4;
254 rel->r_info = ELF32_R_INFO(count + dep->de_global,
255 R_SPARC_32);
256#else
257#error unknown ISA
258#endif
259
260 sym->st_name = base + dofr[j].dofr_name - 1;
261 sym->st_value = 0;
262 sym->st_size = 0;
263 sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_FUNC);
264 sym->st_other = 0;
265 sym->st_shndx = SHN_UNDEF;
266
267 rel++;
268 sym++;
269 count++;
270 }
271 }
272
273 /*
274 * Add a symbol for the DOF itself. We use a different symbol for
275 * lazily and actively loaded DOF to make them easy to distinguish.
276 */
277 sym->st_name = strtabsz;
278 sym->st_value = 0;
279 sym->st_size = dof->dofh_filesz;
280 sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT);
281 sym->st_other = 0;
282 sym->st_shndx = ESHDR_DOF;
283 sym++;
284
285 if (dtp->dt_lazyload) {
286 bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz,
287 sizeof (DOFLAZYSTR));
288 strtabsz += sizeof (DOFLAZYSTR);
289 } else {
290 bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR));
291 strtabsz += sizeof (DOFSTR);
292 }
293
294 assert(count == dep->de_nrel);
295 assert(strtabsz == dep->de_strlen);
296
297 return (0);
298}
299
300
301typedef struct dof_elf64 {
302 uint32_t de_nrel;
303 Elf64_Rela *de_rel;
304 uint32_t de_nsym;
305 Elf64_Sym *de_sym;
306
307 uint32_t de_strlen;
308 char *de_strtab;
309
310 uint32_t de_global;
311} dof_elf64_t;
312
313static int
314prepare_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf64_t *dep)
315{
316 dof_sec_t *dofs, *s;
317 dof_relohdr_t *dofrh;
318 dof_relodesc_t *dofr;
319 char *strtab;
320 int i, j, nrel;
321 size_t strtabsz = 1;
322 uint32_t count = 0;
323 size_t base;
324 Elf64_Sym *sym;
325 Elf64_Rela *rel;
326
327 /*LINTED*/
328 dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff);
329
330 /*
331 * First compute the size of the string table and the number of
332 * relocations present in the DOF.
333 */
334 for (i = 0; i < dof->dofh_secnum; i++) {
335 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
336 continue;
337
338 /*LINTED*/
339 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
340
341 s = &dofs[dofrh->dofr_strtab];
342 strtab = (char *)dof + s->dofs_offset;
343 assert(strtab[0] == '\0');
344 strtabsz += s->dofs_size - 1;
345
346 s = &dofs[dofrh->dofr_relsec];
347 /*LINTED*/
348 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
349 count += s->dofs_size / s->dofs_entsize;
350 }
351
352 dep->de_strlen = strtabsz;
353 dep->de_nrel = count;
354 dep->de_nsym = count + 1; /* the first symbol is always null */
355
356 if (dtp->dt_lazyload) {
357 dep->de_strlen += sizeof (DOFLAZYSTR);
358 dep->de_nsym++;
359 } else {
360 dep->de_strlen += sizeof (DOFSTR);
361 dep->de_nsym++;
362 }
363
364 if ((dep->de_rel = calloc(dep->de_nrel,
365 sizeof (dep->de_rel[0]))) == NULL) {
366 return (dt_set_errno(dtp, EDT_NOMEM));
367 }
368
369 if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf64_Sym))) == NULL) {
370 free(dep->de_rel);
371 return (dt_set_errno(dtp, EDT_NOMEM));
372 }
373
374 if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) {
375 free(dep->de_rel);
376 free(dep->de_sym);
377 return (dt_set_errno(dtp, EDT_NOMEM));
378 }
379
380 count = 0;
381 strtabsz = 1;
382 dep->de_strtab[0] = '\0';
383 rel = dep->de_rel;
384 sym = dep->de_sym;
385 dep->de_global = 1;
386
387 /*
388 * The first symbol table entry must be zeroed and is always ignored.
389 */
390 bzero(sym, sizeof (Elf64_Sym));
391 sym++;
392
393 /*
394 * Take a second pass through the DOF sections filling in the
395 * memory we allocated.
396 */
397 for (i = 0; i < dof->dofh_secnum; i++) {
398 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
399 continue;
400
401 /*LINTED*/
402 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
403
404 s = &dofs[dofrh->dofr_strtab];
405 strtab = (char *)dof + s->dofs_offset;
406 bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size);
407 base = strtabsz;
408 strtabsz += s->dofs_size - 1;
409
410 s = &dofs[dofrh->dofr_relsec];
411 /*LINTED*/
412 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
413 nrel = s->dofs_size / s->dofs_entsize;
414
415 s = &dofs[dofrh->dofr_tgtsec];
416
417 for (j = 0; j < nrel; j++) {
418#ifdef DOODAD
419#if defined(__arm__)
420/* XXX */
421#elif defined(__ia64__)
422/* XXX */
423#elif defined(__mips__)
424/* XXX */
425#elif defined(__powerpc__)
253#elif defined(__sparc)
254 /*
255 * Add 4 bytes to hit the low half of this 64-bit
256 * big-endian address.
257 */
258 rel->r_offset = s->dofs_offset +
259 dofr[j].dofr_offset + 4;
260 rel->r_info = ELF32_R_INFO(count + dep->de_global,
261 R_SPARC_32);
262#else
263#error unknown ISA
264#endif
265
266 sym->st_name = base + dofr[j].dofr_name - 1;
267 sym->st_value = 0;
268 sym->st_size = 0;
269 sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_FUNC);
270 sym->st_other = 0;
271 sym->st_shndx = SHN_UNDEF;
272
273 rel++;
274 sym++;
275 count++;
276 }
277 }
278
279 /*
280 * Add a symbol for the DOF itself. We use a different symbol for
281 * lazily and actively loaded DOF to make them easy to distinguish.
282 */
283 sym->st_name = strtabsz;
284 sym->st_value = 0;
285 sym->st_size = dof->dofh_filesz;
286 sym->st_info = ELF32_ST_INFO(STB_GLOBAL, STT_OBJECT);
287 sym->st_other = 0;
288 sym->st_shndx = ESHDR_DOF;
289 sym++;
290
291 if (dtp->dt_lazyload) {
292 bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz,
293 sizeof (DOFLAZYSTR));
294 strtabsz += sizeof (DOFLAZYSTR);
295 } else {
296 bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR));
297 strtabsz += sizeof (DOFSTR);
298 }
299
300 assert(count == dep->de_nrel);
301 assert(strtabsz == dep->de_strlen);
302
303 return (0);
304}
305
306
307typedef struct dof_elf64 {
308 uint32_t de_nrel;
309 Elf64_Rela *de_rel;
310 uint32_t de_nsym;
311 Elf64_Sym *de_sym;
312
313 uint32_t de_strlen;
314 char *de_strtab;
315
316 uint32_t de_global;
317} dof_elf64_t;
318
319static int
320prepare_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, dof_elf64_t *dep)
321{
322 dof_sec_t *dofs, *s;
323 dof_relohdr_t *dofrh;
324 dof_relodesc_t *dofr;
325 char *strtab;
326 int i, j, nrel;
327 size_t strtabsz = 1;
328 uint32_t count = 0;
329 size_t base;
330 Elf64_Sym *sym;
331 Elf64_Rela *rel;
332
333 /*LINTED*/
334 dofs = (dof_sec_t *)((char *)dof + dof->dofh_secoff);
335
336 /*
337 * First compute the size of the string table and the number of
338 * relocations present in the DOF.
339 */
340 for (i = 0; i < dof->dofh_secnum; i++) {
341 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
342 continue;
343
344 /*LINTED*/
345 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
346
347 s = &dofs[dofrh->dofr_strtab];
348 strtab = (char *)dof + s->dofs_offset;
349 assert(strtab[0] == '\0');
350 strtabsz += s->dofs_size - 1;
351
352 s = &dofs[dofrh->dofr_relsec];
353 /*LINTED*/
354 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
355 count += s->dofs_size / s->dofs_entsize;
356 }
357
358 dep->de_strlen = strtabsz;
359 dep->de_nrel = count;
360 dep->de_nsym = count + 1; /* the first symbol is always null */
361
362 if (dtp->dt_lazyload) {
363 dep->de_strlen += sizeof (DOFLAZYSTR);
364 dep->de_nsym++;
365 } else {
366 dep->de_strlen += sizeof (DOFSTR);
367 dep->de_nsym++;
368 }
369
370 if ((dep->de_rel = calloc(dep->de_nrel,
371 sizeof (dep->de_rel[0]))) == NULL) {
372 return (dt_set_errno(dtp, EDT_NOMEM));
373 }
374
375 if ((dep->de_sym = calloc(dep->de_nsym, sizeof (Elf64_Sym))) == NULL) {
376 free(dep->de_rel);
377 return (dt_set_errno(dtp, EDT_NOMEM));
378 }
379
380 if ((dep->de_strtab = calloc(dep->de_strlen, 1)) == NULL) {
381 free(dep->de_rel);
382 free(dep->de_sym);
383 return (dt_set_errno(dtp, EDT_NOMEM));
384 }
385
386 count = 0;
387 strtabsz = 1;
388 dep->de_strtab[0] = '\0';
389 rel = dep->de_rel;
390 sym = dep->de_sym;
391 dep->de_global = 1;
392
393 /*
394 * The first symbol table entry must be zeroed and is always ignored.
395 */
396 bzero(sym, sizeof (Elf64_Sym));
397 sym++;
398
399 /*
400 * Take a second pass through the DOF sections filling in the
401 * memory we allocated.
402 */
403 for (i = 0; i < dof->dofh_secnum; i++) {
404 if (dofs[i].dofs_type != DOF_SECT_URELHDR)
405 continue;
406
407 /*LINTED*/
408 dofrh = (dof_relohdr_t *)((char *)dof + dofs[i].dofs_offset);
409
410 s = &dofs[dofrh->dofr_strtab];
411 strtab = (char *)dof + s->dofs_offset;
412 bcopy(strtab + 1, dep->de_strtab + strtabsz, s->dofs_size);
413 base = strtabsz;
414 strtabsz += s->dofs_size - 1;
415
416 s = &dofs[dofrh->dofr_relsec];
417 /*LINTED*/
418 dofr = (dof_relodesc_t *)((char *)dof + s->dofs_offset);
419 nrel = s->dofs_size / s->dofs_entsize;
420
421 s = &dofs[dofrh->dofr_tgtsec];
422
423 for (j = 0; j < nrel; j++) {
424#ifdef DOODAD
425#if defined(__arm__)
426/* XXX */
427#elif defined(__ia64__)
428/* XXX */
429#elif defined(__mips__)
430/* XXX */
431#elif defined(__powerpc__)
426/* XXX */
432 rel->r_offset = s->dofs_offset +
433 dofr[j].dofr_offset;
434 rel->r_info = ELF64_R_INFO(count + dep->de_global,
435 R_PPC64_REL64);
427#elif defined(__i386) || defined(__amd64)
428 rel->r_offset = s->dofs_offset +
429 dofr[j].dofr_offset;
430 rel->r_info = ELF64_R_INFO(count + dep->de_global,
431 R_AMD64_64);
432#elif defined(__sparc)
433 rel->r_offset = s->dofs_offset +
434 dofr[j].dofr_offset;
435 rel->r_info = ELF64_R_INFO(count + dep->de_global,
436 R_SPARC_64);
437#else
438#error unknown ISA
439#endif
440#endif
441
442 sym->st_name = base + dofr[j].dofr_name - 1;
443 sym->st_value = 0;
444 sym->st_size = 0;
445 sym->st_info = GELF_ST_INFO(STB_GLOBAL, STT_FUNC);
446 sym->st_other = 0;
447 sym->st_shndx = SHN_UNDEF;
448
449 rel++;
450 sym++;
451 count++;
452 }
453 }
454
455 /*
456 * Add a symbol for the DOF itself. We use a different symbol for
457 * lazily and actively loaded DOF to make them easy to distinguish.
458 */
459 sym->st_name = strtabsz;
460 sym->st_value = 0;
461 sym->st_size = dof->dofh_filesz;
462 sym->st_info = GELF_ST_INFO(STB_GLOBAL, STT_OBJECT);
463 sym->st_other = 0;
464 sym->st_shndx = ESHDR_DOF;
465 sym++;
466
467 if (dtp->dt_lazyload) {
468 bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz,
469 sizeof (DOFLAZYSTR));
470 strtabsz += sizeof (DOFLAZYSTR);
471 } else {
472 bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR));
473 strtabsz += sizeof (DOFSTR);
474 }
475
476 assert(count == dep->de_nrel);
477 assert(strtabsz == dep->de_strlen);
478
479 return (0);
480}
481
482/*
483 * Write out an ELF32 file prologue consisting of a header, section headers,
484 * and a section header string table. The DOF data will follow this prologue
485 * and complete the contents of the given ELF file.
486 */
487static int
488dump_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd)
489{
490 struct {
491 Elf32_Ehdr ehdr;
492 Elf32_Shdr shdr[ESHDR_NUM];
493 } elf_file;
494
495 Elf32_Shdr *shp;
496 Elf32_Off off;
497 dof_elf32_t de;
498 int ret = 0;
499 uint_t nshdr;
500
501 if (prepare_elf32(dtp, dof, &de) != 0)
502 return (-1); /* errno is set for us */
503
504 /*
505 * If there are no relocations, we only need enough sections for
506 * the shstrtab and the DOF.
507 */
508 nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM;
509
510 bzero(&elf_file, sizeof (elf_file));
511
512 elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0;
513 elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1;
514 elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2;
515 elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3;
516 elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT;
517 elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS32;
518#if BYTE_ORDER == _BIG_ENDIAN
519 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
520#else
521 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
522#endif
523#if defined(__FreeBSD__)
524 elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
525#endif
526 elf_file.ehdr.e_type = ET_REL;
527#if defined(__arm__)
528 elf_file.ehdr.e_machine = EM_ARM;
529#elif defined(__ia64__)
530 elf_file.ehdr.e_machine = EM_IA_64;
531#elif defined(__mips__)
532 elf_file.ehdr.e_machine = EM_MIPS;
533#elif defined(__powerpc__)
534 elf_file.ehdr.e_machine = EM_PPC;
535#elif defined(__sparc)
536 elf_file.ehdr.e_machine = EM_SPARC;
537#elif defined(__i386) || defined(__amd64)
538 elf_file.ehdr.e_machine = EM_386;
539#endif
540 elf_file.ehdr.e_version = EV_CURRENT;
541 elf_file.ehdr.e_shoff = sizeof (Elf32_Ehdr);
542 elf_file.ehdr.e_ehsize = sizeof (Elf32_Ehdr);
543 elf_file.ehdr.e_phentsize = sizeof (Elf32_Phdr);
544 elf_file.ehdr.e_shentsize = sizeof (Elf32_Shdr);
545 elf_file.ehdr.e_shnum = nshdr;
546 elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB;
547 off = sizeof (elf_file) + nshdr * sizeof (Elf32_Shdr);
548
549 shp = &elf_file.shdr[ESHDR_SHSTRTAB];
550 shp->sh_name = 1; /* DTRACE_SHSTRTAB32[1] = ".shstrtab" */
551 shp->sh_type = SHT_STRTAB;
552 shp->sh_offset = off;
553 shp->sh_size = sizeof (DTRACE_SHSTRTAB32);
554 shp->sh_addralign = sizeof (char);
555 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
556
557 shp = &elf_file.shdr[ESHDR_DOF];
558 shp->sh_name = 11; /* DTRACE_SHSTRTAB32[11] = ".SUNW_dof" */
559 shp->sh_flags = SHF_ALLOC;
560 shp->sh_type = SHT_SUNW_dof;
561 shp->sh_offset = off;
562 shp->sh_size = dof->dofh_filesz;
563 shp->sh_addralign = 8;
564 off = shp->sh_offset + shp->sh_size;
565
566 shp = &elf_file.shdr[ESHDR_STRTAB];
567 shp->sh_name = 21; /* DTRACE_SHSTRTAB32[21] = ".strtab" */
568 shp->sh_flags = SHF_ALLOC;
569 shp->sh_type = SHT_STRTAB;
570 shp->sh_offset = off;
571 shp->sh_size = de.de_strlen;
572 shp->sh_addralign = sizeof (char);
573 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4);
574
575 shp = &elf_file.shdr[ESHDR_SYMTAB];
576 shp->sh_name = 29; /* DTRACE_SHSTRTAB32[29] = ".symtab" */
577 shp->sh_flags = SHF_ALLOC;
578 shp->sh_type = SHT_SYMTAB;
579 shp->sh_entsize = sizeof (Elf32_Sym);
580 shp->sh_link = ESHDR_STRTAB;
581 shp->sh_offset = off;
582 shp->sh_info = de.de_global;
583 shp->sh_size = de.de_nsym * sizeof (Elf32_Sym);
584 shp->sh_addralign = 4;
585 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4);
586
587 if (de.de_nrel == 0) {
588 if (dt_write(dtp, fd, &elf_file,
589 sizeof (elf_file)) != sizeof (elf_file) ||
590 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) ||
591 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
592 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
593 PWRITE_SCN(ESHDR_DOF, dof)) {
594 ret = dt_set_errno(dtp, errno);
595 }
596 } else {
597 shp = &elf_file.shdr[ESHDR_REL];
598 shp->sh_name = 37; /* DTRACE_SHSTRTAB32[37] = ".rel.SUNW_dof" */
599 shp->sh_flags = SHF_ALLOC;
600#ifdef __sparc
601 shp->sh_type = SHT_RELA;
602#else
603 shp->sh_type = SHT_REL;
604#endif
605 shp->sh_entsize = sizeof (de.de_rel[0]);
606 shp->sh_link = ESHDR_SYMTAB;
607 shp->sh_info = ESHDR_DOF;
608 shp->sh_offset = off;
609 shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]);
610 shp->sh_addralign = 4;
611
612 if (dt_write(dtp, fd, &elf_file,
613 sizeof (elf_file)) != sizeof (elf_file) ||
614 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) ||
615 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
616 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
617 PWRITE_SCN(ESHDR_REL, de.de_rel) ||
618 PWRITE_SCN(ESHDR_DOF, dof)) {
619 ret = dt_set_errno(dtp, errno);
620 }
621 }
622
623 free(de.de_strtab);
624 free(de.de_sym);
625 free(de.de_rel);
626
627 return (ret);
628}
629
630/*
631 * Write out an ELF64 file prologue consisting of a header, section headers,
632 * and a section header string table. The DOF data will follow this prologue
633 * and complete the contents of the given ELF file.
634 */
635static int
636dump_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd)
637{
638 struct {
639 Elf64_Ehdr ehdr;
640 Elf64_Shdr shdr[ESHDR_NUM];
641 } elf_file;
642
643 Elf64_Shdr *shp;
644 Elf64_Off off;
645 dof_elf64_t de;
646 int ret = 0;
647 uint_t nshdr;
648
649 if (prepare_elf64(dtp, dof, &de) != 0)
650 return (-1); /* errno is set for us */
651
652 /*
653 * If there are no relocations, we only need enough sections for
654 * the shstrtab and the DOF.
655 */
656 nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM;
657
658 bzero(&elf_file, sizeof (elf_file));
659
660 elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0;
661 elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1;
662 elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2;
663 elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3;
664 elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT;
665 elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS64;
666#if BYTE_ORDER == _BIG_ENDIAN
667 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
668#else
669 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
670#endif
671#if defined(__FreeBSD__)
672 elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
673#endif
674 elf_file.ehdr.e_type = ET_REL;
675#if defined(__arm__)
676 elf_file.ehdr.e_machine = EM_ARM;
677#elif defined(__ia64__)
678 elf_file.ehdr.e_machine = EM_IA_64;
679#elif defined(__mips__)
680 elf_file.ehdr.e_machine = EM_MIPS;
681#elif defined(__powerpc__)
682 elf_file.ehdr.e_machine = EM_PPC;
683#elif defined(__sparc)
684 elf_file.ehdr.e_machine = EM_SPARCV9;
685#elif defined(__i386) || defined(__amd64)
686 elf_file.ehdr.e_machine = EM_AMD64;
687#endif
688 elf_file.ehdr.e_version = EV_CURRENT;
689 elf_file.ehdr.e_shoff = sizeof (Elf64_Ehdr);
690 elf_file.ehdr.e_ehsize = sizeof (Elf64_Ehdr);
691 elf_file.ehdr.e_phentsize = sizeof (Elf64_Phdr);
692 elf_file.ehdr.e_shentsize = sizeof (Elf64_Shdr);
693 elf_file.ehdr.e_shnum = nshdr;
694 elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB;
695 off = sizeof (elf_file) + nshdr * sizeof (Elf64_Shdr);
696
697 shp = &elf_file.shdr[ESHDR_SHSTRTAB];
698 shp->sh_name = 1; /* DTRACE_SHSTRTAB64[1] = ".shstrtab" */
699 shp->sh_type = SHT_STRTAB;
700 shp->sh_offset = off;
701 shp->sh_size = sizeof (DTRACE_SHSTRTAB64);
702 shp->sh_addralign = sizeof (char);
703 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
704
705 shp = &elf_file.shdr[ESHDR_DOF];
706 shp->sh_name = 11; /* DTRACE_SHSTRTAB64[11] = ".SUNW_dof" */
707 shp->sh_flags = SHF_ALLOC;
708 shp->sh_type = SHT_SUNW_dof;
709 shp->sh_offset = off;
710 shp->sh_size = dof->dofh_filesz;
711 shp->sh_addralign = 8;
712 off = shp->sh_offset + shp->sh_size;
713
714 shp = &elf_file.shdr[ESHDR_STRTAB];
715 shp->sh_name = 21; /* DTRACE_SHSTRTAB64[21] = ".strtab" */
716 shp->sh_flags = SHF_ALLOC;
717 shp->sh_type = SHT_STRTAB;
718 shp->sh_offset = off;
719 shp->sh_size = de.de_strlen;
720 shp->sh_addralign = sizeof (char);
721 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
722
723 shp = &elf_file.shdr[ESHDR_SYMTAB];
724 shp->sh_name = 29; /* DTRACE_SHSTRTAB64[29] = ".symtab" */
725 shp->sh_flags = SHF_ALLOC;
726 shp->sh_type = SHT_SYMTAB;
727 shp->sh_entsize = sizeof (Elf64_Sym);
728 shp->sh_link = ESHDR_STRTAB;
729 shp->sh_offset = off;
730 shp->sh_info = de.de_global;
731 shp->sh_size = de.de_nsym * sizeof (Elf64_Sym);
732 shp->sh_addralign = 8;
733 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
734
735 if (de.de_nrel == 0) {
736 if (dt_write(dtp, fd, &elf_file,
737 sizeof (elf_file)) != sizeof (elf_file) ||
738 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) ||
739 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
740 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
741 PWRITE_SCN(ESHDR_DOF, dof)) {
742 ret = dt_set_errno(dtp, errno);
743 }
744 } else {
745 shp = &elf_file.shdr[ESHDR_REL];
746 shp->sh_name = 37; /* DTRACE_SHSTRTAB64[37] = ".rel.SUNW_dof" */
747 shp->sh_flags = SHF_ALLOC;
748 shp->sh_type = SHT_RELA;
749 shp->sh_entsize = sizeof (de.de_rel[0]);
750 shp->sh_link = ESHDR_SYMTAB;
751 shp->sh_info = ESHDR_DOF;
752 shp->sh_offset = off;
753 shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]);
754 shp->sh_addralign = 8;
755
756 if (dt_write(dtp, fd, &elf_file,
757 sizeof (elf_file)) != sizeof (elf_file) ||
758 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) ||
759 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
760 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
761 PWRITE_SCN(ESHDR_REL, de.de_rel) ||
762 PWRITE_SCN(ESHDR_DOF, dof)) {
763 ret = dt_set_errno(dtp, errno);
764 }
765 }
766
767 free(de.de_strtab);
768 free(de.de_sym);
769 free(de.de_rel);
770
771 return (ret);
772}
773
774static int
775dt_symtab_lookup(Elf_Data *data_sym, int nsym, uintptr_t addr, uint_t shn,
776 GElf_Sym *sym)
777{
778 int i, ret = -1;
779 GElf_Sym s;
780
781 for (i = 0; i < nsym && gelf_getsym(data_sym, i, sym) != NULL; i++) {
782 if (GELF_ST_TYPE(sym->st_info) == STT_FUNC &&
783 shn == sym->st_shndx &&
784 sym->st_value <= addr &&
785 addr < sym->st_value + sym->st_size) {
786 if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL)
787 return (0);
788
789 ret = 0;
790 s = *sym;
791 }
792 }
793
794 if (ret == 0)
795 *sym = s;
796 return (ret);
797}
798
799#if defined(__arm__)
800/* XXX */
801static int
802dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
803 uint32_t *off)
804{
805printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
806 return (0);
807}
808#elif defined(__ia64__)
809/* XXX */
810static int
811dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
812 uint32_t *off)
813{
814printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
815 return (0);
816}
817#elif defined(__mips__)
818/* XXX */
819static int
820dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
821 uint32_t *off)
822{
823printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
824 return (0);
825}
826#elif defined(__powerpc__)
436#elif defined(__i386) || defined(__amd64)
437 rel->r_offset = s->dofs_offset +
438 dofr[j].dofr_offset;
439 rel->r_info = ELF64_R_INFO(count + dep->de_global,
440 R_AMD64_64);
441#elif defined(__sparc)
442 rel->r_offset = s->dofs_offset +
443 dofr[j].dofr_offset;
444 rel->r_info = ELF64_R_INFO(count + dep->de_global,
445 R_SPARC_64);
446#else
447#error unknown ISA
448#endif
449#endif
450
451 sym->st_name = base + dofr[j].dofr_name - 1;
452 sym->st_value = 0;
453 sym->st_size = 0;
454 sym->st_info = GELF_ST_INFO(STB_GLOBAL, STT_FUNC);
455 sym->st_other = 0;
456 sym->st_shndx = SHN_UNDEF;
457
458 rel++;
459 sym++;
460 count++;
461 }
462 }
463
464 /*
465 * Add a symbol for the DOF itself. We use a different symbol for
466 * lazily and actively loaded DOF to make them easy to distinguish.
467 */
468 sym->st_name = strtabsz;
469 sym->st_value = 0;
470 sym->st_size = dof->dofh_filesz;
471 sym->st_info = GELF_ST_INFO(STB_GLOBAL, STT_OBJECT);
472 sym->st_other = 0;
473 sym->st_shndx = ESHDR_DOF;
474 sym++;
475
476 if (dtp->dt_lazyload) {
477 bcopy(DOFLAZYSTR, dep->de_strtab + strtabsz,
478 sizeof (DOFLAZYSTR));
479 strtabsz += sizeof (DOFLAZYSTR);
480 } else {
481 bcopy(DOFSTR, dep->de_strtab + strtabsz, sizeof (DOFSTR));
482 strtabsz += sizeof (DOFSTR);
483 }
484
485 assert(count == dep->de_nrel);
486 assert(strtabsz == dep->de_strlen);
487
488 return (0);
489}
490
491/*
492 * Write out an ELF32 file prologue consisting of a header, section headers,
493 * and a section header string table. The DOF data will follow this prologue
494 * and complete the contents of the given ELF file.
495 */
496static int
497dump_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd)
498{
499 struct {
500 Elf32_Ehdr ehdr;
501 Elf32_Shdr shdr[ESHDR_NUM];
502 } elf_file;
503
504 Elf32_Shdr *shp;
505 Elf32_Off off;
506 dof_elf32_t de;
507 int ret = 0;
508 uint_t nshdr;
509
510 if (prepare_elf32(dtp, dof, &de) != 0)
511 return (-1); /* errno is set for us */
512
513 /*
514 * If there are no relocations, we only need enough sections for
515 * the shstrtab and the DOF.
516 */
517 nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM;
518
519 bzero(&elf_file, sizeof (elf_file));
520
521 elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0;
522 elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1;
523 elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2;
524 elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3;
525 elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT;
526 elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS32;
527#if BYTE_ORDER == _BIG_ENDIAN
528 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
529#else
530 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
531#endif
532#if defined(__FreeBSD__)
533 elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
534#endif
535 elf_file.ehdr.e_type = ET_REL;
536#if defined(__arm__)
537 elf_file.ehdr.e_machine = EM_ARM;
538#elif defined(__ia64__)
539 elf_file.ehdr.e_machine = EM_IA_64;
540#elif defined(__mips__)
541 elf_file.ehdr.e_machine = EM_MIPS;
542#elif defined(__powerpc__)
543 elf_file.ehdr.e_machine = EM_PPC;
544#elif defined(__sparc)
545 elf_file.ehdr.e_machine = EM_SPARC;
546#elif defined(__i386) || defined(__amd64)
547 elf_file.ehdr.e_machine = EM_386;
548#endif
549 elf_file.ehdr.e_version = EV_CURRENT;
550 elf_file.ehdr.e_shoff = sizeof (Elf32_Ehdr);
551 elf_file.ehdr.e_ehsize = sizeof (Elf32_Ehdr);
552 elf_file.ehdr.e_phentsize = sizeof (Elf32_Phdr);
553 elf_file.ehdr.e_shentsize = sizeof (Elf32_Shdr);
554 elf_file.ehdr.e_shnum = nshdr;
555 elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB;
556 off = sizeof (elf_file) + nshdr * sizeof (Elf32_Shdr);
557
558 shp = &elf_file.shdr[ESHDR_SHSTRTAB];
559 shp->sh_name = 1; /* DTRACE_SHSTRTAB32[1] = ".shstrtab" */
560 shp->sh_type = SHT_STRTAB;
561 shp->sh_offset = off;
562 shp->sh_size = sizeof (DTRACE_SHSTRTAB32);
563 shp->sh_addralign = sizeof (char);
564 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
565
566 shp = &elf_file.shdr[ESHDR_DOF];
567 shp->sh_name = 11; /* DTRACE_SHSTRTAB32[11] = ".SUNW_dof" */
568 shp->sh_flags = SHF_ALLOC;
569 shp->sh_type = SHT_SUNW_dof;
570 shp->sh_offset = off;
571 shp->sh_size = dof->dofh_filesz;
572 shp->sh_addralign = 8;
573 off = shp->sh_offset + shp->sh_size;
574
575 shp = &elf_file.shdr[ESHDR_STRTAB];
576 shp->sh_name = 21; /* DTRACE_SHSTRTAB32[21] = ".strtab" */
577 shp->sh_flags = SHF_ALLOC;
578 shp->sh_type = SHT_STRTAB;
579 shp->sh_offset = off;
580 shp->sh_size = de.de_strlen;
581 shp->sh_addralign = sizeof (char);
582 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4);
583
584 shp = &elf_file.shdr[ESHDR_SYMTAB];
585 shp->sh_name = 29; /* DTRACE_SHSTRTAB32[29] = ".symtab" */
586 shp->sh_flags = SHF_ALLOC;
587 shp->sh_type = SHT_SYMTAB;
588 shp->sh_entsize = sizeof (Elf32_Sym);
589 shp->sh_link = ESHDR_STRTAB;
590 shp->sh_offset = off;
591 shp->sh_info = de.de_global;
592 shp->sh_size = de.de_nsym * sizeof (Elf32_Sym);
593 shp->sh_addralign = 4;
594 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 4);
595
596 if (de.de_nrel == 0) {
597 if (dt_write(dtp, fd, &elf_file,
598 sizeof (elf_file)) != sizeof (elf_file) ||
599 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) ||
600 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
601 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
602 PWRITE_SCN(ESHDR_DOF, dof)) {
603 ret = dt_set_errno(dtp, errno);
604 }
605 } else {
606 shp = &elf_file.shdr[ESHDR_REL];
607 shp->sh_name = 37; /* DTRACE_SHSTRTAB32[37] = ".rel.SUNW_dof" */
608 shp->sh_flags = SHF_ALLOC;
609#ifdef __sparc
610 shp->sh_type = SHT_RELA;
611#else
612 shp->sh_type = SHT_REL;
613#endif
614 shp->sh_entsize = sizeof (de.de_rel[0]);
615 shp->sh_link = ESHDR_SYMTAB;
616 shp->sh_info = ESHDR_DOF;
617 shp->sh_offset = off;
618 shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]);
619 shp->sh_addralign = 4;
620
621 if (dt_write(dtp, fd, &elf_file,
622 sizeof (elf_file)) != sizeof (elf_file) ||
623 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB32) ||
624 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
625 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
626 PWRITE_SCN(ESHDR_REL, de.de_rel) ||
627 PWRITE_SCN(ESHDR_DOF, dof)) {
628 ret = dt_set_errno(dtp, errno);
629 }
630 }
631
632 free(de.de_strtab);
633 free(de.de_sym);
634 free(de.de_rel);
635
636 return (ret);
637}
638
639/*
640 * Write out an ELF64 file prologue consisting of a header, section headers,
641 * and a section header string table. The DOF data will follow this prologue
642 * and complete the contents of the given ELF file.
643 */
644static int
645dump_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, int fd)
646{
647 struct {
648 Elf64_Ehdr ehdr;
649 Elf64_Shdr shdr[ESHDR_NUM];
650 } elf_file;
651
652 Elf64_Shdr *shp;
653 Elf64_Off off;
654 dof_elf64_t de;
655 int ret = 0;
656 uint_t nshdr;
657
658 if (prepare_elf64(dtp, dof, &de) != 0)
659 return (-1); /* errno is set for us */
660
661 /*
662 * If there are no relocations, we only need enough sections for
663 * the shstrtab and the DOF.
664 */
665 nshdr = de.de_nrel == 0 ? ESHDR_SYMTAB + 1 : ESHDR_NUM;
666
667 bzero(&elf_file, sizeof (elf_file));
668
669 elf_file.ehdr.e_ident[EI_MAG0] = ELFMAG0;
670 elf_file.ehdr.e_ident[EI_MAG1] = ELFMAG1;
671 elf_file.ehdr.e_ident[EI_MAG2] = ELFMAG2;
672 elf_file.ehdr.e_ident[EI_MAG3] = ELFMAG3;
673 elf_file.ehdr.e_ident[EI_VERSION] = EV_CURRENT;
674 elf_file.ehdr.e_ident[EI_CLASS] = ELFCLASS64;
675#if BYTE_ORDER == _BIG_ENDIAN
676 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2MSB;
677#else
678 elf_file.ehdr.e_ident[EI_DATA] = ELFDATA2LSB;
679#endif
680#if defined(__FreeBSD__)
681 elf_file.ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
682#endif
683 elf_file.ehdr.e_type = ET_REL;
684#if defined(__arm__)
685 elf_file.ehdr.e_machine = EM_ARM;
686#elif defined(__ia64__)
687 elf_file.ehdr.e_machine = EM_IA_64;
688#elif defined(__mips__)
689 elf_file.ehdr.e_machine = EM_MIPS;
690#elif defined(__powerpc__)
691 elf_file.ehdr.e_machine = EM_PPC;
692#elif defined(__sparc)
693 elf_file.ehdr.e_machine = EM_SPARCV9;
694#elif defined(__i386) || defined(__amd64)
695 elf_file.ehdr.e_machine = EM_AMD64;
696#endif
697 elf_file.ehdr.e_version = EV_CURRENT;
698 elf_file.ehdr.e_shoff = sizeof (Elf64_Ehdr);
699 elf_file.ehdr.e_ehsize = sizeof (Elf64_Ehdr);
700 elf_file.ehdr.e_phentsize = sizeof (Elf64_Phdr);
701 elf_file.ehdr.e_shentsize = sizeof (Elf64_Shdr);
702 elf_file.ehdr.e_shnum = nshdr;
703 elf_file.ehdr.e_shstrndx = ESHDR_SHSTRTAB;
704 off = sizeof (elf_file) + nshdr * sizeof (Elf64_Shdr);
705
706 shp = &elf_file.shdr[ESHDR_SHSTRTAB];
707 shp->sh_name = 1; /* DTRACE_SHSTRTAB64[1] = ".shstrtab" */
708 shp->sh_type = SHT_STRTAB;
709 shp->sh_offset = off;
710 shp->sh_size = sizeof (DTRACE_SHSTRTAB64);
711 shp->sh_addralign = sizeof (char);
712 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
713
714 shp = &elf_file.shdr[ESHDR_DOF];
715 shp->sh_name = 11; /* DTRACE_SHSTRTAB64[11] = ".SUNW_dof" */
716 shp->sh_flags = SHF_ALLOC;
717 shp->sh_type = SHT_SUNW_dof;
718 shp->sh_offset = off;
719 shp->sh_size = dof->dofh_filesz;
720 shp->sh_addralign = 8;
721 off = shp->sh_offset + shp->sh_size;
722
723 shp = &elf_file.shdr[ESHDR_STRTAB];
724 shp->sh_name = 21; /* DTRACE_SHSTRTAB64[21] = ".strtab" */
725 shp->sh_flags = SHF_ALLOC;
726 shp->sh_type = SHT_STRTAB;
727 shp->sh_offset = off;
728 shp->sh_size = de.de_strlen;
729 shp->sh_addralign = sizeof (char);
730 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
731
732 shp = &elf_file.shdr[ESHDR_SYMTAB];
733 shp->sh_name = 29; /* DTRACE_SHSTRTAB64[29] = ".symtab" */
734 shp->sh_flags = SHF_ALLOC;
735 shp->sh_type = SHT_SYMTAB;
736 shp->sh_entsize = sizeof (Elf64_Sym);
737 shp->sh_link = ESHDR_STRTAB;
738 shp->sh_offset = off;
739 shp->sh_info = de.de_global;
740 shp->sh_size = de.de_nsym * sizeof (Elf64_Sym);
741 shp->sh_addralign = 8;
742 off = P2ROUNDUP(shp->sh_offset + shp->sh_size, 8);
743
744 if (de.de_nrel == 0) {
745 if (dt_write(dtp, fd, &elf_file,
746 sizeof (elf_file)) != sizeof (elf_file) ||
747 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) ||
748 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
749 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
750 PWRITE_SCN(ESHDR_DOF, dof)) {
751 ret = dt_set_errno(dtp, errno);
752 }
753 } else {
754 shp = &elf_file.shdr[ESHDR_REL];
755 shp->sh_name = 37; /* DTRACE_SHSTRTAB64[37] = ".rel.SUNW_dof" */
756 shp->sh_flags = SHF_ALLOC;
757 shp->sh_type = SHT_RELA;
758 shp->sh_entsize = sizeof (de.de_rel[0]);
759 shp->sh_link = ESHDR_SYMTAB;
760 shp->sh_info = ESHDR_DOF;
761 shp->sh_offset = off;
762 shp->sh_size = de.de_nrel * sizeof (de.de_rel[0]);
763 shp->sh_addralign = 8;
764
765 if (dt_write(dtp, fd, &elf_file,
766 sizeof (elf_file)) != sizeof (elf_file) ||
767 PWRITE_SCN(ESHDR_SHSTRTAB, DTRACE_SHSTRTAB64) ||
768 PWRITE_SCN(ESHDR_STRTAB, de.de_strtab) ||
769 PWRITE_SCN(ESHDR_SYMTAB, de.de_sym) ||
770 PWRITE_SCN(ESHDR_REL, de.de_rel) ||
771 PWRITE_SCN(ESHDR_DOF, dof)) {
772 ret = dt_set_errno(dtp, errno);
773 }
774 }
775
776 free(de.de_strtab);
777 free(de.de_sym);
778 free(de.de_rel);
779
780 return (ret);
781}
782
783static int
784dt_symtab_lookup(Elf_Data *data_sym, int nsym, uintptr_t addr, uint_t shn,
785 GElf_Sym *sym)
786{
787 int i, ret = -1;
788 GElf_Sym s;
789
790 for (i = 0; i < nsym && gelf_getsym(data_sym, i, sym) != NULL; i++) {
791 if (GELF_ST_TYPE(sym->st_info) == STT_FUNC &&
792 shn == sym->st_shndx &&
793 sym->st_value <= addr &&
794 addr < sym->st_value + sym->st_size) {
795 if (GELF_ST_BIND(sym->st_info) == STB_GLOBAL)
796 return (0);
797
798 ret = 0;
799 s = *sym;
800 }
801 }
802
803 if (ret == 0)
804 *sym = s;
805 return (ret);
806}
807
808#if defined(__arm__)
809/* XXX */
810static int
811dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
812 uint32_t *off)
813{
814printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
815 return (0);
816}
817#elif defined(__ia64__)
818/* XXX */
819static int
820dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
821 uint32_t *off)
822{
823printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
824 return (0);
825}
826#elif defined(__mips__)
827/* XXX */
828static int
829dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
830 uint32_t *off)
831{
832printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
833 return (0);
834}
835#elif defined(__powerpc__)
836/* The sentinel is 'xor r3,r3,r3'. */
837#define DT_OP_XOR_R3 0x7c631a78
838
839#define DT_OP_NOP 0x60000000
840#define DT_OP_BLR 0x4e800020
841
842/* This captures all forms of branching to address. */
843#define DT_IS_BRANCH(inst) ((inst & 0xfc000000) == 0x48000000)
844#define DT_IS_BL(inst) (DT_IS_BRANCH(inst) && (inst & 0x01))
845
827/* XXX */
828static int
829dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
830 uint32_t *off)
831{
846/* XXX */
847static int
848dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
849 uint32_t *off)
850{
832printf("%s:%s(%d): DOODAD\n",__FUNCTION__,__FILE__,__LINE__);
851 uint32_t *ip;
852
853 if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0)
854 return (-1);
855
856 /*LINTED*/
857 ip = (uint32_t *)(p + rela->r_offset);
858
859 /*
860 * We only know about some specific relocation types.
861 */
862 if (GELF_R_TYPE(rela->r_info) != R_PPC_REL24 &&
863 GELF_R_TYPE(rela->r_info) != R_PPC_PLTREL24)
864 return (-1);
865
866 /*
867 * We may have already processed this object file in an earlier linker
868 * invocation. Check to see if the present instruction sequence matches
869 * the one we would install below.
870 */
871 if (isenabled) {
872 if (ip[0] == DT_OP_XOR_R3) {
873 (*off) += sizeof (ip[0]);
874 return (0);
875 }
876 } else {
877 if (ip[0] == DT_OP_NOP) {
878 (*off) += sizeof (ip[0]);
879 return (0);
880 }
881 }
882
883 /*
884 * We only expect branch to address instructions.
885 */
886 if (!DT_IS_BRANCH(ip[0])) {
887 dt_dprintf("found %x instead of a branch instruction at %llx\n",
888 ip[0], (u_longlong_t)rela->r_offset);
889 return (-1);
890 }
891
892 if (isenabled) {
893 /*
894 * It would necessarily indicate incorrect usage if an is-
895 * enabled probe were tail-called so flag that as an error.
896 * It's also potentially (very) tricky to handle gracefully,
897 * but could be done if this were a desired use scenario.
898 */
899 if (!DT_IS_BL(ip[0])) {
900 dt_dprintf("tail call to is-enabled probe at %llx\n",
901 (u_longlong_t)rela->r_offset);
902 return (-1);
903 }
904
905 ip[0] = DT_OP_XOR_R3;
906 (*off) += sizeof (ip[0]);
907 } else {
908 if (DT_IS_BL(ip[0]))
909 ip[0] = DT_OP_NOP;
910 else
911 ip[0] = DT_OP_BLR;
912 }
913
833 return (0);
834}
835
836#elif defined(__sparc)
837
838#define DT_OP_RET 0x81c7e008
839#define DT_OP_NOP 0x01000000
840#define DT_OP_CALL 0x40000000
841#define DT_OP_CLR_O0 0x90102000
842
843#define DT_IS_MOV_O7(inst) (((inst) & 0xffffe000) == 0x9e100000)
844#define DT_IS_RESTORE(inst) (((inst) & 0xc1f80000) == 0x81e80000)
845#define DT_IS_RETL(inst) (((inst) & 0xfff83fff) == 0x81c02008)
846
847#define DT_RS2(inst) ((inst) & 0x1f)
848#define DT_MAKE_RETL(reg) (0x81c02008 | ((reg) << 14))
849
850/*ARGSUSED*/
851static int
852dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
853 uint32_t *off)
854{
855 uint32_t *ip;
856
857 if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0)
858 return (-1);
859
860 /*LINTED*/
861 ip = (uint32_t *)(p + rela->r_offset);
862
863 /*
864 * We only know about some specific relocation types.
865 */
866 if (GELF_R_TYPE(rela->r_info) != R_SPARC_WDISP30 &&
867 GELF_R_TYPE(rela->r_info) != R_SPARC_WPLT30)
868 return (-1);
869
870 /*
871 * We may have already processed this object file in an earlier linker
872 * invocation. Check to see if the present instruction sequence matches
873 * the one we would install below.
874 */
875 if (isenabled) {
876 if (ip[0] == DT_OP_NOP) {
877 (*off) += sizeof (ip[0]);
878 return (0);
879 }
880 } else {
881 if (DT_IS_RESTORE(ip[1])) {
882 if (ip[0] == DT_OP_RET) {
883 (*off) += sizeof (ip[0]);
884 return (0);
885 }
886 } else if (DT_IS_MOV_O7(ip[1])) {
887 if (DT_IS_RETL(ip[0]))
888 return (0);
889 } else {
890 if (ip[0] == DT_OP_NOP) {
891 (*off) += sizeof (ip[0]);
892 return (0);
893 }
894 }
895 }
896
897 /*
898 * We only expect call instructions with a displacement of 0.
899 */
900 if (ip[0] != DT_OP_CALL) {
901 dt_dprintf("found %x instead of a call instruction at %llx\n",
902 ip[0], (u_longlong_t)rela->r_offset);
903 return (-1);
904 }
905
906 if (isenabled) {
907 /*
908 * It would necessarily indicate incorrect usage if an is-
909 * enabled probe were tail-called so flag that as an error.
910 * It's also potentially (very) tricky to handle gracefully,
911 * but could be done if this were a desired use scenario.
912 */
913 if (DT_IS_RESTORE(ip[1]) || DT_IS_MOV_O7(ip[1])) {
914 dt_dprintf("tail call to is-enabled probe at %llx\n",
915 (u_longlong_t)rela->r_offset);
916 return (-1);
917 }
918
919
920 /*
921 * On SPARC, we take advantage of the fact that the first
922 * argument shares the same register as for the return value.
923 * The macro handles the work of zeroing that register so we
924 * don't need to do anything special here. We instrument the
925 * instruction in the delay slot as we'll need to modify the
926 * return register after that instruction has been emulated.
927 */
928 ip[0] = DT_OP_NOP;
929 (*off) += sizeof (ip[0]);
930 } else {
931 /*
932 * If the call is followed by a restore, it's a tail call so
933 * change the call to a ret. If the call if followed by a mov
934 * of a register into %o7, it's a tail call in leaf context
935 * so change the call to a retl-like instruction that returns
936 * to that register value + 8 (rather than the typical %o7 +
937 * 8); the delay slot instruction is left, but should have no
938 * effect. Otherwise we change the call to be a nop. We
939 * identify the subsequent instruction as the probe point in
940 * all but the leaf tail-call case to ensure that arguments to
941 * the probe are complete and consistent. An astute, though
942 * largely hypothetical, observer would note that there is the
943 * possibility of a false-positive probe firing if the function
944 * contained a branch to the instruction in the delay slot of
945 * the call. Fixing this would require significant in-kernel
946 * modifications, and isn't worth doing until we see it in the
947 * wild.
948 */
949 if (DT_IS_RESTORE(ip[1])) {
950 ip[0] = DT_OP_RET;
951 (*off) += sizeof (ip[0]);
952 } else if (DT_IS_MOV_O7(ip[1])) {
953 ip[0] = DT_MAKE_RETL(DT_RS2(ip[1]));
954 } else {
955 ip[0] = DT_OP_NOP;
956 (*off) += sizeof (ip[0]);
957 }
958 }
959
960 return (0);
961}
962
963#elif defined(__i386) || defined(__amd64)
964
965#define DT_OP_NOP 0x90
966#define DT_OP_RET 0xc3
967#define DT_OP_CALL 0xe8
968#define DT_OP_JMP32 0xe9
969#define DT_OP_REX_RAX 0x48
970#define DT_OP_XOR_EAX_0 0x33
971#define DT_OP_XOR_EAX_1 0xc0
972
973static int
974dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
975 uint32_t *off)
976{
977 uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1);
978 uint8_t ret;
979
980 /*
981 * On x86, the first byte of the instruction is the call opcode and
982 * the next four bytes are the 32-bit address; the relocation is for
983 * the address operand. We back up the offset to the first byte of
984 * the instruction. For is-enabled probes, we later advance the offset
985 * so that it hits the first nop in the instruction sequence.
986 */
987 (*off) -= 1;
988
989 /*
990 * We only know about some specific relocation types. Luckily
991 * these types have the same values on both 32-bit and 64-bit
992 * x86 architectures.
993 */
994 if (GELF_R_TYPE(rela->r_info) != R_386_PC32 &&
995 GELF_R_TYPE(rela->r_info) != R_386_PLT32)
996 return (-1);
997
998 /*
999 * We may have already processed this object file in an earlier linker
1000 * invocation. Check to see if the present instruction sequence matches
1001 * the one we would install. For is-enabled probes, we advance the
1002 * offset to the first nop instruction in the sequence to match the
1003 * text modification code below.
1004 */
1005 if (!isenabled) {
1006 if ((ip[0] == DT_OP_NOP || ip[0] == DT_OP_RET) &&
1007 ip[1] == DT_OP_NOP && ip[2] == DT_OP_NOP &&
1008 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP)
1009 return (0);
1010 } else if (dtp->dt_oflags & DTRACE_O_LP64) {
1011 if (ip[0] == DT_OP_REX_RAX &&
1012 ip[1] == DT_OP_XOR_EAX_0 && ip[2] == DT_OP_XOR_EAX_1 &&
1013 (ip[3] == DT_OP_NOP || ip[3] == DT_OP_RET) &&
1014 ip[4] == DT_OP_NOP) {
1015 (*off) += 3;
1016 return (0);
1017 }
1018 } else {
1019 if (ip[0] == DT_OP_XOR_EAX_0 && ip[1] == DT_OP_XOR_EAX_1 &&
1020 (ip[2] == DT_OP_NOP || ip[2] == DT_OP_RET) &&
1021 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) {
1022 (*off) += 2;
1023 return (0);
1024 }
1025 }
1026
1027 /*
1028 * We expect either a call instrution with a 32-bit displacement or a
1029 * jmp instruction with a 32-bit displacement acting as a tail-call.
1030 */
1031 if (ip[0] != DT_OP_CALL && ip[0] != DT_OP_JMP32) {
1032 dt_dprintf("found %x instead of a call or jmp instruction at "
1033 "%llx\n", ip[0], (u_longlong_t)rela->r_offset);
1034 return (-1);
1035 }
1036
1037 ret = (ip[0] == DT_OP_JMP32) ? DT_OP_RET : DT_OP_NOP;
1038
1039 /*
1040 * Establish the instruction sequence -- all nops for probes, and an
1041 * instruction to clear the return value register (%eax/%rax) followed
1042 * by nops for is-enabled probes. For is-enabled probes, we advance
1043 * the offset to the first nop. This isn't stricly necessary but makes
1044 * for more readable disassembly when the probe is enabled.
1045 */
1046 if (!isenabled) {
1047 ip[0] = ret;
1048 ip[1] = DT_OP_NOP;
1049 ip[2] = DT_OP_NOP;
1050 ip[3] = DT_OP_NOP;
1051 ip[4] = DT_OP_NOP;
1052 } else if (dtp->dt_oflags & DTRACE_O_LP64) {
1053 ip[0] = DT_OP_REX_RAX;
1054 ip[1] = DT_OP_XOR_EAX_0;
1055 ip[2] = DT_OP_XOR_EAX_1;
1056 ip[3] = ret;
1057 ip[4] = DT_OP_NOP;
1058 (*off) += 3;
1059 } else {
1060 ip[0] = DT_OP_XOR_EAX_0;
1061 ip[1] = DT_OP_XOR_EAX_1;
1062 ip[2] = ret;
1063 ip[3] = DT_OP_NOP;
1064 ip[4] = DT_OP_NOP;
1065 (*off) += 2;
1066 }
1067
1068 return (0);
1069}
1070
1071#else
1072#error unknown ISA
1073#endif
1074
1075/*PRINTFLIKE5*/
1076static int
1077dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs,
1078 const char *format, ...)
1079{
1080 va_list ap;
1081 dt_link_pair_t *pair;
1082
1083 va_start(ap, format);
1084 dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap);
1085 va_end(ap);
1086
1087 if (elf != NULL)
1088 (void) elf_end(elf);
1089
1090 if (fd >= 0)
1091 (void) close(fd);
1092
1093 while ((pair = bufs) != NULL) {
1094 bufs = pair->dlp_next;
1095 dt_free(dtp, pair->dlp_str);
1096 dt_free(dtp, pair->dlp_sym);
1097 dt_free(dtp, pair);
1098 }
1099
1100 return (dt_set_errno(dtp, EDT_COMPILER));
1101}
1102
1103static int
1104process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp)
1105{
1106 static const char dt_prefix[] = "__dtrace";
1107 static const char dt_enabled[] = "enabled";
1108 static const char dt_symprefix[] = "$dtrace";
1109 static const char dt_symfmt[] = "%s%ld.%s";
1110 int fd, i, ndx, eprobe, mod = 0;
1111 Elf *elf = NULL;
1112 GElf_Ehdr ehdr;
1113 Elf_Scn *scn_rel, *scn_sym, *scn_str, *scn_tgt;
1114 Elf_Data *data_rel, *data_sym, *data_str, *data_tgt;
1115 GElf_Shdr shdr_rel, shdr_sym, shdr_str, shdr_tgt;
1116 GElf_Sym rsym, fsym, dsym;
1117 GElf_Rela rela;
1118 char *s, *p, *r;
1119 char pname[DTRACE_PROVNAMELEN];
1120 dt_provider_t *pvp;
1121 dt_probe_t *prp;
1122 uint32_t off, eclass, emachine1, emachine2;
1123 size_t symsize, nsym, isym, istr, len;
1124 key_t objkey;
1125 dt_link_pair_t *pair, *bufs = NULL;
1126 dt_strtab_t *strtab;
1127
1128 if ((fd = open64(obj, O_RDWR)) == -1) {
1129 return (dt_link_error(dtp, elf, fd, bufs,
1130 "failed to open %s: %s", obj, strerror(errno)));
1131 }
1132
1133 if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) {
1134 return (dt_link_error(dtp, elf, fd, bufs,
1135 "failed to process %s: %s", obj, elf_errmsg(elf_errno())));
1136 }
1137
1138 switch (elf_kind(elf)) {
1139 case ELF_K_ELF:
1140 break;
1141 case ELF_K_AR:
1142 return (dt_link_error(dtp, elf, fd, bufs, "archives are not "
1143 "permitted; use the contents of the archive instead: %s",
1144 obj));
1145 default:
1146 return (dt_link_error(dtp, elf, fd, bufs,
1147 "invalid file type: %s", obj));
1148 }
1149
1150 if (gelf_getehdr(elf, &ehdr) == NULL) {
1151 return (dt_link_error(dtp, elf, fd, bufs, "corrupt file: %s",
1152 obj));
1153 }
1154
1155 if (dtp->dt_oflags & DTRACE_O_LP64) {
1156 eclass = ELFCLASS64;
1157#if defined(__ia64__)
1158 emachine1 = emachine2 = EM_IA_64;
1159#elif defined(__mips__)
1160 emachine1 = emachine2 = EM_MIPS;
1161#elif defined(__powerpc__)
1162 emachine1 = emachine2 = EM_PPC64;
1163#elif defined(__sparc)
1164 emachine1 = emachine2 = EM_SPARCV9;
1165#elif defined(__i386) || defined(__amd64)
1166 emachine1 = emachine2 = EM_AMD64;
1167#endif
1168 symsize = sizeof (Elf64_Sym);
1169 } else {
1170 eclass = ELFCLASS32;
1171#if defined(__arm__)
1172 emachine1 = emachine2 = EM_ARM;
1173#elif defined(__mips__)
1174 emachine1 = emachine2 = EM_MIPS;
1175#elif defined(__powerpc__)
1176 emachine1 = emachine2 = EM_PPC;
1177#elif defined(__sparc)
1178 emachine1 = EM_SPARC;
1179 emachine2 = EM_SPARC32PLUS;
1180#elif defined(__i386) || defined(__amd64) || defined(__ia64__)
1181 emachine1 = emachine2 = EM_386;
1182#endif
1183 symsize = sizeof (Elf32_Sym);
1184 }
1185
1186 if (ehdr.e_ident[EI_CLASS] != eclass) {
1187 return (dt_link_error(dtp, elf, fd, bufs,
1188 "incorrect ELF class for object file: %s", obj));
1189 }
1190
1191 if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2) {
1192 return (dt_link_error(dtp, elf, fd, bufs,
1193 "incorrect ELF machine type for object file: %s", obj));
1194 }
1195
1196 /*
1197 * We use this token as a relatively unique handle for this file on the
1198 * system in order to disambiguate potential conflicts between files of
1199 * the same name which contain identially named local symbols.
1200 */
1201 if ((objkey = ftok(obj, 0)) == (key_t)-1) {
1202 return (dt_link_error(dtp, elf, fd, bufs,
1203 "failed to generate unique key for object file: %s", obj));
1204 }
1205
1206 scn_rel = NULL;
1207 while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) {
1208 if (gelf_getshdr(scn_rel, &shdr_rel) == NULL)
1209 goto err;
1210
1211 /*
1212 * Skip any non-relocation sections.
1213 */
1214 if (shdr_rel.sh_type != SHT_RELA && shdr_rel.sh_type != SHT_REL)
1215 continue;
1216
1217 if ((data_rel = elf_getdata(scn_rel, NULL)) == NULL)
1218 goto err;
1219
1220 /*
1221 * Grab the section, section header and section data for the
1222 * symbol table that this relocation section references.
1223 */
1224 if ((scn_sym = elf_getscn(elf, shdr_rel.sh_link)) == NULL ||
1225 gelf_getshdr(scn_sym, &shdr_sym) == NULL ||
1226 (data_sym = elf_getdata(scn_sym, NULL)) == NULL)
1227 goto err;
1228
1229 /*
1230 * Ditto for that symbol table's string table.
1231 */
1232 if ((scn_str = elf_getscn(elf, shdr_sym.sh_link)) == NULL ||
1233 gelf_getshdr(scn_str, &shdr_str) == NULL ||
1234 (data_str = elf_getdata(scn_str, NULL)) == NULL)
1235 goto err;
1236
1237 /*
1238 * Grab the section, section header and section data for the
1239 * target section for the relocations. For the relocations
1240 * we're looking for -- this will typically be the text of the
1241 * object file.
1242 */
1243 if ((scn_tgt = elf_getscn(elf, shdr_rel.sh_info)) == NULL ||
1244 gelf_getshdr(scn_tgt, &shdr_tgt) == NULL ||
1245 (data_tgt = elf_getdata(scn_tgt, NULL)) == NULL)
1246 goto err;
1247
1248 /*
1249 * We're looking for relocations to symbols matching this form:
1250 *
1251 * __dtrace[enabled]_<prov>___<probe>
1252 *
1253 * For the generated object, we need to record the location
1254 * identified by the relocation, and create a new relocation
1255 * in the generated object that will be resolved at link time
1256 * to the location of the function in which the probe is
1257 * embedded. In the target object, we change the matched symbol
1258 * so that it will be ignored at link time, and we modify the
1259 * target (text) section to replace the call instruction with
1260 * one or more nops.
1261 *
1262 * If the function containing the probe is locally scoped
1263 * (static), we create an alias used by the relocation in the
1264 * generated object. The alias, a new symbol, will be global
1265 * (so that the relocation from the generated object can be
1266 * resolved), and hidden (so that it is converted to a local
1267 * symbol at link time). Such aliases have this form:
1268 *
1269 * $dtrace<key>.<function>
1270 *
1271 * We take a first pass through all the relocations to
1272 * populate our string table and count the number of extra
1273 * symbols we'll require.
1274 */
1275 strtab = dt_strtab_create(1);
1276 nsym = 0;
1277 isym = data_sym->d_size / symsize;
1278 istr = data_str->d_size;
1279
1280 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) {
1281
1282 if (shdr_rel.sh_type == SHT_RELA) {
1283 if (gelf_getrela(data_rel, i, &rela) == NULL)
1284 continue;
1285 } else {
1286 GElf_Rel rel;
1287 if (gelf_getrel(data_rel, i, &rel) == NULL)
1288 continue;
1289 rela.r_offset = rel.r_offset;
1290 rela.r_info = rel.r_info;
1291 rela.r_addend = 0;
1292 }
1293
1294 if (gelf_getsym(data_sym, GELF_R_SYM(rela.r_info),
1295 &rsym) == NULL) {
1296 dt_strtab_destroy(strtab);
1297 goto err;
1298 }
1299
1300 s = (char *)data_str->d_buf + rsym.st_name;
1301
1302 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0)
1303 continue;
1304
1305 if (dt_symtab_lookup(data_sym, isym, rela.r_offset,
1306 shdr_rel.sh_info, &fsym) != 0) {
1307 dt_strtab_destroy(strtab);
1308 goto err;
1309 }
1310
1311 if (GELF_ST_BIND(fsym.st_info) != STB_LOCAL)
1312 continue;
1313
1314 if (fsym.st_name > data_str->d_size) {
1315 dt_strtab_destroy(strtab);
1316 goto err;
1317 }
1318
1319 s = (char *)data_str->d_buf + fsym.st_name;
1320
1321 /*
1322 * If this symbol isn't of type function, we've really
1323 * driven off the rails or the object file is corrupt.
1324 */
1325 if (GELF_ST_TYPE(fsym.st_info) != STT_FUNC) {
1326 dt_strtab_destroy(strtab);
1327 return (dt_link_error(dtp, elf, fd, bufs,
1328 "expected %s to be of type function", s));
1329 }
1330
1331 len = snprintf(NULL, 0, dt_symfmt, dt_symprefix,
1332 objkey, s) + 1;
1333 if ((p = dt_alloc(dtp, len)) == NULL) {
1334 dt_strtab_destroy(strtab);
1335 goto err;
1336 }
1337 (void) snprintf(p, len, dt_symfmt, dt_symprefix,
1338 objkey, s);
1339
1340 if (dt_strtab_index(strtab, p) == -1) {
1341 nsym++;
1342 (void) dt_strtab_insert(strtab, p);
1343 }
1344
1345 dt_free(dtp, p);
1346 }
1347
1348 /*
1349 * If needed, allocate the additional space for the symbol
1350 * table and string table copying the old data into the new
1351 * buffers, and marking the buffers as dirty. We inject those
1352 * newly allocated buffers into the libelf data structures, but
1353 * are still responsible for freeing them once we're done with
1354 * the elf handle.
1355 */
1356 if (nsym > 0) {
1357 /*
1358 * The first byte of the string table is reserved for
1359 * the \0 entry.
1360 */
1361 len = dt_strtab_size(strtab) - 1;
1362
1363 assert(len > 0);
1364 assert(dt_strtab_index(strtab, "") == 0);
1365
1366 dt_strtab_destroy(strtab);
1367
1368 if ((pair = dt_alloc(dtp, sizeof (*pair))) == NULL)
1369 goto err;
1370
1371 if ((pair->dlp_str = dt_alloc(dtp, data_str->d_size +
1372 len)) == NULL) {
1373 dt_free(dtp, pair);
1374 goto err;
1375 }
1376
1377 if ((pair->dlp_sym = dt_alloc(dtp, data_sym->d_size +
1378 nsym * symsize)) == NULL) {
1379 dt_free(dtp, pair->dlp_str);
1380 dt_free(dtp, pair);
1381 goto err;
1382 }
1383
1384 pair->dlp_next = bufs;
1385 bufs = pair;
1386
1387 bcopy(data_str->d_buf, pair->dlp_str, data_str->d_size);
1388 data_str->d_buf = pair->dlp_str;
1389 data_str->d_size += len;
1390 (void) elf_flagdata(data_str, ELF_C_SET, ELF_F_DIRTY);
1391
1392 shdr_str.sh_size += len;
1393 (void) gelf_update_shdr(scn_str, &shdr_str);
1394
1395 bcopy(data_sym->d_buf, pair->dlp_sym, data_sym->d_size);
1396 data_sym->d_buf = pair->dlp_sym;
1397 data_sym->d_size += nsym * symsize;
1398 (void) elf_flagdata(data_sym, ELF_C_SET, ELF_F_DIRTY);
1399
1400 shdr_sym.sh_size += nsym * symsize;
1401 (void) gelf_update_shdr(scn_sym, &shdr_sym);
1402
1403 nsym += isym;
1404 } else {
1405 dt_strtab_destroy(strtab);
1406 }
1407
1408 /*
1409 * Now that the tables have been allocated, perform the
1410 * modifications described above.
1411 */
1412 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) {
1413
1414 if (shdr_rel.sh_type == SHT_RELA) {
1415 if (gelf_getrela(data_rel, i, &rela) == NULL)
1416 continue;
1417 } else {
1418 GElf_Rel rel;
1419 if (gelf_getrel(data_rel, i, &rel) == NULL)
1420 continue;
1421 rela.r_offset = rel.r_offset;
1422 rela.r_info = rel.r_info;
1423 rela.r_addend = 0;
1424 }
1425
1426 ndx = GELF_R_SYM(rela.r_info);
1427
1428 if (gelf_getsym(data_sym, ndx, &rsym) == NULL ||
1429 rsym.st_name > data_str->d_size)
1430 goto err;
1431
1432 s = (char *)data_str->d_buf + rsym.st_name;
1433
1434 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0)
1435 continue;
1436
1437 s += sizeof (dt_prefix) - 1;
1438
1439 /*
1440 * Check to see if this is an 'is-enabled' check as
1441 * opposed to a normal probe.
1442 */
1443 if (strncmp(s, dt_enabled,
1444 sizeof (dt_enabled) - 1) == 0) {
1445 s += sizeof (dt_enabled) - 1;
1446 eprobe = 1;
1447 *eprobesp = 1;
1448 dt_dprintf("is-enabled probe\n");
1449 } else {
1450 eprobe = 0;
1451 dt_dprintf("normal probe\n");
1452 }
1453
1454 if (*s++ != '_')
1455 goto err;
1456
1457 if ((p = strstr(s, "___")) == NULL ||
1458 p - s >= sizeof (pname))
1459 goto err;
1460
1461 bcopy(s, pname, p - s);
1462 pname[p - s] = '\0';
1463
1464 p = strhyphenate(p + 3); /* strlen("___") */
1465
1466 if (dt_symtab_lookup(data_sym, isym, rela.r_offset,
1467 shdr_rel.sh_info, &fsym) != 0)
1468 goto err;
1469
1470 if (fsym.st_name > data_str->d_size)
1471 goto err;
1472
1473 assert(GELF_ST_TYPE(fsym.st_info) == STT_FUNC);
1474
1475 /*
1476 * If a NULL relocation name is passed to
1477 * dt_probe_define(), the function name is used for the
1478 * relocation. The relocation needs to use a mangled
1479 * name if the symbol is locally scoped; the function
1480 * name may need to change if we've found the global
1481 * alias for the locally scoped symbol (we prefer
1482 * global symbols to locals in dt_symtab_lookup()).
1483 */
1484 s = (char *)data_str->d_buf + fsym.st_name;
1485 r = NULL;
1486
1487 if (GELF_ST_BIND(fsym.st_info) == STB_LOCAL) {
1488 dsym = fsym;
1489 dsym.st_name = istr;
1490 dsym.st_info = GELF_ST_INFO(STB_GLOBAL,
1491 STT_FUNC);
1492 dsym.st_other =
1493 ELF64_ST_VISIBILITY(STV_ELIMINATE);
1494 (void) gelf_update_sym(data_sym, isym, &dsym);
1495
1496 r = (char *)data_str->d_buf + istr;
1497 istr += 1 + sprintf(r, dt_symfmt,
1498 dt_symprefix, objkey, s);
1499 isym++;
1500 assert(isym <= nsym);
1501
1502 } else if (strncmp(s, dt_symprefix,
1503 strlen(dt_symprefix)) == 0) {
1504 r = s;
1505 if ((s = strchr(s, '.')) == NULL)
1506 goto err;
1507 s++;
1508 }
1509
1510 if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) {
1511 return (dt_link_error(dtp, elf, fd, bufs,
1512 "no such provider %s", pname));
1513 }
1514
1515 if ((prp = dt_probe_lookup(pvp, p)) == NULL) {
1516 return (dt_link_error(dtp, elf, fd, bufs,
1517 "no such probe %s", p));
1518 }
1519
1520 assert(fsym.st_value <= rela.r_offset);
1521
1522 off = rela.r_offset - fsym.st_value;
1523 if (dt_modtext(dtp, data_tgt->d_buf, eprobe,
1524 &rela, &off) != 0)
1525 goto err;
1526
1527 if (dt_probe_define(pvp, prp, s, r, off, eprobe) != 0) {
1528 return (dt_link_error(dtp, elf, fd, bufs,
1529 "failed to allocate space for probe"));
1530 }
1531#if !defined(sun)
1532 /*
1533 * Our linker doesn't understand the SUNW_IGNORE ndx and
1534 * will try to use this relocation when we build the
1535 * final executable. Since we are done processing this
1536 * relocation, mark it as inexistant and let libelf
1537 * remove it from the file.
1538 * If this wasn't done, we would have garbage added to
1539 * the executable file as the symbol is going to be
1540 * change from UND to ABS.
1541 */
1542 rela.r_offset = 0;
1543 rela.r_info = 0;
1544 rela.r_addend = 0;
1545 (void) gelf_update_rela(data_rel, i, &rela);
1546#endif
1547
1548 mod = 1;
1549 (void) elf_flagdata(data_tgt, ELF_C_SET, ELF_F_DIRTY);
1550
1551 /*
1552 * This symbol may already have been marked to
1553 * be ignored by another relocation referencing
1554 * the same symbol or if this object file has
1555 * already been processed by an earlier link
1556 * invocation.
1557 */
1558#if !defined(sun)
1559#define SHN_SUNW_IGNORE SHN_ABS
1560#endif
1561 if (rsym.st_shndx != SHN_SUNW_IGNORE) {
1562 rsym.st_shndx = SHN_SUNW_IGNORE;
1563 (void) gelf_update_sym(data_sym, ndx, &rsym);
1564 }
1565 }
1566 }
1567
1568 if (mod && elf_update(elf, ELF_C_WRITE) == -1)
1569 goto err;
1570
1571 (void) elf_end(elf);
1572 (void) close(fd);
1573
1574#if !defined(sun)
1575 if (nsym > 0)
1576#endif
1577 while ((pair = bufs) != NULL) {
1578 bufs = pair->dlp_next;
1579 dt_free(dtp, pair->dlp_str);
1580 dt_free(dtp, pair->dlp_sym);
1581 dt_free(dtp, pair);
1582 }
1583
1584 return (0);
1585
1586err:
1587 return (dt_link_error(dtp, elf, fd, bufs,
1588 "an error was encountered while processing %s", obj));
1589}
1590
1591int
1592dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags,
1593 const char *file, int objc, char *const objv[])
1594{
1595#if !defined(sun)
1596 char tfile[PATH_MAX];
1597 Elf *e;
1598 Elf_Scn *scn;
1599 Elf_Data *data;
1600 GElf_Shdr shdr;
1601 int efd;
1602 size_t stridx;
1603 unsigned char *buf;
1604 char *s;
1605 int loc;
1606 GElf_Ehdr ehdr;
1607 Elf_Scn *scn0;
1608 GElf_Shdr shdr0;
1609 uint64_t off, rc;
1610#endif
1611 char drti[PATH_MAX];
1612 dof_hdr_t *dof;
1613 int fd, status, i, cur;
1614 char *cmd, tmp;
1615 size_t len;
1616 int eprobes = 0, ret = 0;
1617
1618#if !defined(sun)
1619 if (access(file, R_OK) == 0) {
1620 fprintf(stderr, "dtrace: target object (%s) already exists. "
1621 "Please remove the target\ndtrace: object and rebuild all "
1622 "the source objects if you wish to run the DTrace\n"
1623 "dtrace: linking process again\n", file);
1624 /*
1625 * Several build infrastructures run DTrace twice (e.g.
1626 * postgres) and we don't want the build to fail. Return
1627 * 0 here since this isn't really a fatal error.
1628 */
1629 return (0);
1630 }
1631 /* XXX Should get a temp file name here. */
1632 snprintf(tfile, sizeof(tfile), "%s.tmp", file);
1633#endif
1634
1635 /*
1636 * A NULL program indicates a special use in which we just link
1637 * together a bunch of object files specified in objv and then
1638 * unlink(2) those object files.
1639 */
1640 if (pgp == NULL) {
1641 const char *fmt = "%s -o %s -r";
1642
1643 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file) + 1;
1644
1645 for (i = 0; i < objc; i++)
1646 len += strlen(objv[i]) + 1;
1647
1648 cmd = alloca(len);
1649
1650 cur = snprintf(cmd, len, fmt, dtp->dt_ld_path, file);
1651
1652 for (i = 0; i < objc; i++)
1653 cur += snprintf(cmd + cur, len - cur, " %s", objv[i]);
1654
1655 if ((status = system(cmd)) == -1) {
1656 return (dt_link_error(dtp, NULL, -1, NULL,
1657 "failed to run %s: %s", dtp->dt_ld_path,
1658 strerror(errno)));
1659 }
1660
1661 if (WIFSIGNALED(status)) {
1662 return (dt_link_error(dtp, NULL, -1, NULL,
1663 "failed to link %s: %s failed due to signal %d",
1664 file, dtp->dt_ld_path, WTERMSIG(status)));
1665 }
1666
1667 if (WEXITSTATUS(status) != 0) {
1668 return (dt_link_error(dtp, NULL, -1, NULL,
1669 "failed to link %s: %s exited with status %d\n",
1670 file, dtp->dt_ld_path, WEXITSTATUS(status)));
1671 }
1672
1673 for (i = 0; i < objc; i++) {
1674 if (strcmp(objv[i], file) != 0)
1675 (void) unlink(objv[i]);
1676 }
1677
1678 return (0);
1679 }
1680
1681 for (i = 0; i < objc; i++) {
1682 if (process_obj(dtp, objv[i], &eprobes) != 0)
1683 return (-1); /* errno is set for us */
1684 }
1685
1686 /*
1687 * If there are is-enabled probes then we need to force use of DOF
1688 * version 2.
1689 */
1690 if (eprobes && pgp->dp_dofversion < DOF_VERSION_2)
1691 pgp->dp_dofversion = DOF_VERSION_2;
1692
1693 if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL)
1694 return (-1); /* errno is set for us */
1695
1696#if defined(sun)
1697 /*
1698 * Create a temporary file and then unlink it if we're going to
1699 * combine it with drti.o later. We can still refer to it in child
1700 * processes as /dev/fd/<fd>.
1701 */
1702 if ((fd = open64(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1) {
1703 return (dt_link_error(dtp, NULL, -1, NULL,
1704 "failed to open %s: %s", file, strerror(errno)));
1705 }
1706#else
1707 if ((fd = open(tfile, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1)
1708 return (dt_link_error(dtp, NULL, -1, NULL,
1709 "failed to open %s: %s", tfile, strerror(errno)));
1710#endif
1711
1712 /*
1713 * If -xlinktype=DOF has been selected, just write out the DOF.
1714 * Otherwise proceed to the default of generating and linking ELF.
1715 */
1716 switch (dtp->dt_linktype) {
1717 case DT_LTYP_DOF:
1718 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz)
1719 ret = errno;
1720
1721 if (close(fd) != 0 && ret == 0)
1722 ret = errno;
1723
1724 if (ret != 0) {
1725 return (dt_link_error(dtp, NULL, -1, NULL,
1726 "failed to write %s: %s", file, strerror(ret)));
1727 }
1728
1729 return (0);
1730
1731 case DT_LTYP_ELF:
1732 break; /* fall through to the rest of dtrace_program_link() */
1733
1734 default:
1735 return (dt_link_error(dtp, NULL, -1, NULL,
1736 "invalid link type %u\n", dtp->dt_linktype));
1737 }
1738
1739
1740#if defined(sun)
1741 if (!dtp->dt_lazyload)
1742 (void) unlink(file);
1743#endif
1744
1745#if defined(sun)
1746 if (dtp->dt_oflags & DTRACE_O_LP64)
1747 status = dump_elf64(dtp, dof, fd);
1748 else
1749 status = dump_elf32(dtp, dof, fd);
1750
1751 if (status != 0 || lseek(fd, 0, SEEK_SET) != 0) {
1752#else
1753 /* We don't write the ELF header, just the DOF section */
1754 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz) {
1755#endif
1756 return (dt_link_error(dtp, NULL, -1, NULL,
1757 "failed to write %s: %s", file, strerror(errno)));
1758 }
1759
1760 if (!dtp->dt_lazyload) {
1761#if defined(sun)
1762 const char *fmt = "%s -o %s -r -Blocal -Breduce /dev/fd/%d %s";
1763
1764 if (dtp->dt_oflags & DTRACE_O_LP64) {
1765 (void) snprintf(drti, sizeof (drti),
1766 "%s/64/drti.o", _dtrace_libdir);
1767 } else {
1768 (void) snprintf(drti, sizeof (drti),
1769 "%s/drti.o", _dtrace_libdir);
1770 }
1771
1772 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, fd,
1773 drti) + 1;
1774
1775 cmd = alloca(len);
1776
1777 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, fd, drti);
1778#else
1779 const char *fmt = "%s -o %s -r %s";
1780
1781#if defined(__amd64__)
1782 /*
1783 * Arches which default to 64-bit need to explicitly use
1784 * the 32-bit library path.
1785 */
1786 int use_32 = !(dtp->dt_oflags & DTRACE_O_LP64);
1787#else
1788 /*
1789 * Arches which are 32-bit only just use the normal
1790 * library path.
1791 */
1792 int use_32 = 0;
1793#endif
1794
1795 (void) snprintf(drti, sizeof (drti), "/usr/lib%s/dtrace/drti.o",
1796 use_32 ? "32":"");
1797
1798 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, tfile,
1799 drti) + 1;
1800
1801#if !defined(sun)
1802 len *= 2;
1803#endif
1804 cmd = alloca(len);
1805
1806 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file,
1807 drti);
1808#endif
1809 if ((status = system(cmd)) == -1) {
1810 ret = dt_link_error(dtp, NULL, -1, NULL,
1811 "failed to run %s: %s", dtp->dt_ld_path,
1812 strerror(errno));
1813 goto done;
1814 }
1815
1816 if (WIFSIGNALED(status)) {
1817 ret = dt_link_error(dtp, NULL, -1, NULL,
1818 "failed to link %s: %s failed due to signal %d",
1819 file, dtp->dt_ld_path, WTERMSIG(status));
1820 goto done;
1821 }
1822
1823 if (WEXITSTATUS(status) != 0) {
1824 ret = dt_link_error(dtp, NULL, -1, NULL,
1825 "failed to link %s: %s exited with status %d\n",
1826 file, dtp->dt_ld_path, WEXITSTATUS(status));
1827 goto done;
1828 }
1829#if !defined(sun)
1830#define BROKEN_LIBELF
1831 /*
1832 * FreeBSD's ld(1) is not instructed to interpret and add
1833 * correctly the SUNW_dof section present in tfile.
1834 * We use libelf to add this section manually and hope the next
1835 * ld invocation won't remove it.
1836 */
1837 elf_version(EV_CURRENT);
1838 if ((efd = open(file, O_RDWR, 0)) < 0) {
1839 ret = dt_link_error(dtp, NULL, -1, NULL,
1840 "failed to open file %s: %s",
1841 file, strerror(errno));
1842 goto done;
1843 }
1844 if ((e = elf_begin(efd, ELF_C_RDWR, NULL)) == NULL) {
1845 close(efd);
1846 ret = dt_link_error(dtp, NULL, -1, NULL,
1847 "failed to open elf file: %s",
1848 elf_errmsg(elf_errno()));
1849 goto done;
1850 }
1851 /*
1852 * Add the string '.SUWN_dof' to the shstrtab section.
1853 */
1854#ifdef BROKEN_LIBELF
1855 elf_flagelf(e, ELF_C_SET, ELF_F_LAYOUT);
1856#endif
1857 elf_getshdrstrndx(e, &stridx);
1858 scn = elf_getscn(e, stridx);
1859 gelf_getshdr(scn, &shdr);
1860 data = elf_newdata(scn);
1861 data->d_off = shdr.sh_size;
1862 data->d_buf = ".SUNW_dof";
1863 data->d_size = 10;
1864 data->d_type = ELF_T_BYTE;
1865 loc = shdr.sh_size;
1866 shdr.sh_size += data->d_size;
1867 gelf_update_shdr(scn, &shdr);
1868#ifdef BROKEN_LIBELF
1869 off = shdr.sh_offset;
1870 rc = shdr.sh_offset + shdr.sh_size;
1871 gelf_getehdr(e, &ehdr);
1872 if (ehdr.e_shoff > off) {
1873 off = ehdr.e_shoff + ehdr.e_shnum * ehdr.e_shentsize;
1874 rc = roundup(rc, 8);
1875 ehdr.e_shoff = rc;
1876 gelf_update_ehdr(e, &ehdr);
1877 rc += ehdr.e_shnum * ehdr.e_shentsize;
1878 }
1879 for (;;) {
1880 scn0 = NULL;
1881 scn = NULL;
1882 while ((scn = elf_nextscn(e, scn)) != NULL) {
1883 gelf_getshdr(scn, &shdr);
1884 if (shdr.sh_type == SHT_NOBITS ||
1885 shdr.sh_offset < off)
1886 continue;
1887 /* Find the immediately adjcent section. */
1888 if (scn0 == NULL ||
1889 shdr.sh_offset < shdr0.sh_offset) {
1890 scn0 = scn;
1891 gelf_getshdr(scn0, &shdr0);
1892 }
1893 }
1894 if (scn0 == NULL)
1895 break;
1896 /* Load section data to work around another bug */
1897 elf_getdata(scn0, NULL);
1898 /* Update section header, assure section alignment */
1899 off = shdr0.sh_offset + shdr0.sh_size;
1900 rc = roundup(rc, shdr0.sh_addralign);
1901 shdr0.sh_offset = rc;
1902 gelf_update_shdr(scn0, &shdr0);
1903 rc += shdr0.sh_size;
1904 }
1905 if (elf_update(e, ELF_C_WRITE) < 0) {
1906 ret = dt_link_error(dtp, NULL, -1, NULL,
1907 "failed to add append the shstrtab section: %s",
1908 elf_errmsg(elf_errno()));
1909 elf_end(e);
1910 close(efd);
1911 goto done;
1912 }
1913 elf_end(e);
1914 e = elf_begin(efd, ELF_C_RDWR, NULL);
1915#endif
1916 /*
1917 * Construct the .SUNW_dof section.
1918 */
1919 scn = elf_newscn(e);
1920 data = elf_newdata(scn);
1921 buf = mmap(NULL, dof->dofh_filesz, PROT_READ, MAP_SHARED,
1922 fd, 0);
1923 if (buf == MAP_FAILED) {
1924 ret = dt_link_error(dtp, NULL, -1, NULL,
1925 "failed to mmap buffer %s", strerror(errno));
1926 elf_end(e);
1927 close(efd);
1928 goto done;
1929 }
1930 data->d_buf = buf;
1931 data->d_align = 4;
1932 data->d_size = dof->dofh_filesz;
1933 data->d_version = EV_CURRENT;
1934 gelf_getshdr(scn, &shdr);
1935 shdr.sh_name = loc;
1936 shdr.sh_flags = SHF_ALLOC;
1937 /*
1938 * Actually this should be SHT_SUNW_dof, but FreeBSD's ld(1)
1939 * will remove this 'unknown' section when we try to create an
1940 * executable using the object we are modifying, so we stop
1941 * playing by the rules and use SHT_PROGBITS.
1942 * Also, note that our drti has modifications to handle this.
1943 */
1944 shdr.sh_type = SHT_PROGBITS;
1945 shdr.sh_addralign = 4;
1946 gelf_update_shdr(scn, &shdr);
1947 if (elf_update(e, ELF_C_WRITE) < 0) {
1948 ret = dt_link_error(dtp, NULL, -1, NULL,
1949 "failed to add the SUNW_dof section: %s",
1950 elf_errmsg(elf_errno()));
1951 munmap(buf, dof->dofh_filesz);
1952 elf_end(e);
1953 close(efd);
1954 goto done;
1955 }
1956 munmap(buf, dof->dofh_filesz);
1957 elf_end(e);
1958 close(efd);
1959#endif
1960 (void) close(fd); /* release temporary file */
1961 } else {
1962 (void) close(fd);
1963 }
1964
1965done:
1966 dtrace_dof_destroy(dtp, dof);
1967
1968#if !defined(sun)
1969 unlink(tfile);
1970#endif
1971 return (ret);
1972}
914 return (0);
915}
916
917#elif defined(__sparc)
918
919#define DT_OP_RET 0x81c7e008
920#define DT_OP_NOP 0x01000000
921#define DT_OP_CALL 0x40000000
922#define DT_OP_CLR_O0 0x90102000
923
924#define DT_IS_MOV_O7(inst) (((inst) & 0xffffe000) == 0x9e100000)
925#define DT_IS_RESTORE(inst) (((inst) & 0xc1f80000) == 0x81e80000)
926#define DT_IS_RETL(inst) (((inst) & 0xfff83fff) == 0x81c02008)
927
928#define DT_RS2(inst) ((inst) & 0x1f)
929#define DT_MAKE_RETL(reg) (0x81c02008 | ((reg) << 14))
930
931/*ARGSUSED*/
932static int
933dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
934 uint32_t *off)
935{
936 uint32_t *ip;
937
938 if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0)
939 return (-1);
940
941 /*LINTED*/
942 ip = (uint32_t *)(p + rela->r_offset);
943
944 /*
945 * We only know about some specific relocation types.
946 */
947 if (GELF_R_TYPE(rela->r_info) != R_SPARC_WDISP30 &&
948 GELF_R_TYPE(rela->r_info) != R_SPARC_WPLT30)
949 return (-1);
950
951 /*
952 * We may have already processed this object file in an earlier linker
953 * invocation. Check to see if the present instruction sequence matches
954 * the one we would install below.
955 */
956 if (isenabled) {
957 if (ip[0] == DT_OP_NOP) {
958 (*off) += sizeof (ip[0]);
959 return (0);
960 }
961 } else {
962 if (DT_IS_RESTORE(ip[1])) {
963 if (ip[0] == DT_OP_RET) {
964 (*off) += sizeof (ip[0]);
965 return (0);
966 }
967 } else if (DT_IS_MOV_O7(ip[1])) {
968 if (DT_IS_RETL(ip[0]))
969 return (0);
970 } else {
971 if (ip[0] == DT_OP_NOP) {
972 (*off) += sizeof (ip[0]);
973 return (0);
974 }
975 }
976 }
977
978 /*
979 * We only expect call instructions with a displacement of 0.
980 */
981 if (ip[0] != DT_OP_CALL) {
982 dt_dprintf("found %x instead of a call instruction at %llx\n",
983 ip[0], (u_longlong_t)rela->r_offset);
984 return (-1);
985 }
986
987 if (isenabled) {
988 /*
989 * It would necessarily indicate incorrect usage if an is-
990 * enabled probe were tail-called so flag that as an error.
991 * It's also potentially (very) tricky to handle gracefully,
992 * but could be done if this were a desired use scenario.
993 */
994 if (DT_IS_RESTORE(ip[1]) || DT_IS_MOV_O7(ip[1])) {
995 dt_dprintf("tail call to is-enabled probe at %llx\n",
996 (u_longlong_t)rela->r_offset);
997 return (-1);
998 }
999
1000
1001 /*
1002 * On SPARC, we take advantage of the fact that the first
1003 * argument shares the same register as for the return value.
1004 * The macro handles the work of zeroing that register so we
1005 * don't need to do anything special here. We instrument the
1006 * instruction in the delay slot as we'll need to modify the
1007 * return register after that instruction has been emulated.
1008 */
1009 ip[0] = DT_OP_NOP;
1010 (*off) += sizeof (ip[0]);
1011 } else {
1012 /*
1013 * If the call is followed by a restore, it's a tail call so
1014 * change the call to a ret. If the call if followed by a mov
1015 * of a register into %o7, it's a tail call in leaf context
1016 * so change the call to a retl-like instruction that returns
1017 * to that register value + 8 (rather than the typical %o7 +
1018 * 8); the delay slot instruction is left, but should have no
1019 * effect. Otherwise we change the call to be a nop. We
1020 * identify the subsequent instruction as the probe point in
1021 * all but the leaf tail-call case to ensure that arguments to
1022 * the probe are complete and consistent. An astute, though
1023 * largely hypothetical, observer would note that there is the
1024 * possibility of a false-positive probe firing if the function
1025 * contained a branch to the instruction in the delay slot of
1026 * the call. Fixing this would require significant in-kernel
1027 * modifications, and isn't worth doing until we see it in the
1028 * wild.
1029 */
1030 if (DT_IS_RESTORE(ip[1])) {
1031 ip[0] = DT_OP_RET;
1032 (*off) += sizeof (ip[0]);
1033 } else if (DT_IS_MOV_O7(ip[1])) {
1034 ip[0] = DT_MAKE_RETL(DT_RS2(ip[1]));
1035 } else {
1036 ip[0] = DT_OP_NOP;
1037 (*off) += sizeof (ip[0]);
1038 }
1039 }
1040
1041 return (0);
1042}
1043
1044#elif defined(__i386) || defined(__amd64)
1045
1046#define DT_OP_NOP 0x90
1047#define DT_OP_RET 0xc3
1048#define DT_OP_CALL 0xe8
1049#define DT_OP_JMP32 0xe9
1050#define DT_OP_REX_RAX 0x48
1051#define DT_OP_XOR_EAX_0 0x33
1052#define DT_OP_XOR_EAX_1 0xc0
1053
1054static int
1055dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela,
1056 uint32_t *off)
1057{
1058 uint8_t *ip = (uint8_t *)(p + rela->r_offset - 1);
1059 uint8_t ret;
1060
1061 /*
1062 * On x86, the first byte of the instruction is the call opcode and
1063 * the next four bytes are the 32-bit address; the relocation is for
1064 * the address operand. We back up the offset to the first byte of
1065 * the instruction. For is-enabled probes, we later advance the offset
1066 * so that it hits the first nop in the instruction sequence.
1067 */
1068 (*off) -= 1;
1069
1070 /*
1071 * We only know about some specific relocation types. Luckily
1072 * these types have the same values on both 32-bit and 64-bit
1073 * x86 architectures.
1074 */
1075 if (GELF_R_TYPE(rela->r_info) != R_386_PC32 &&
1076 GELF_R_TYPE(rela->r_info) != R_386_PLT32)
1077 return (-1);
1078
1079 /*
1080 * We may have already processed this object file in an earlier linker
1081 * invocation. Check to see if the present instruction sequence matches
1082 * the one we would install. For is-enabled probes, we advance the
1083 * offset to the first nop instruction in the sequence to match the
1084 * text modification code below.
1085 */
1086 if (!isenabled) {
1087 if ((ip[0] == DT_OP_NOP || ip[0] == DT_OP_RET) &&
1088 ip[1] == DT_OP_NOP && ip[2] == DT_OP_NOP &&
1089 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP)
1090 return (0);
1091 } else if (dtp->dt_oflags & DTRACE_O_LP64) {
1092 if (ip[0] == DT_OP_REX_RAX &&
1093 ip[1] == DT_OP_XOR_EAX_0 && ip[2] == DT_OP_XOR_EAX_1 &&
1094 (ip[3] == DT_OP_NOP || ip[3] == DT_OP_RET) &&
1095 ip[4] == DT_OP_NOP) {
1096 (*off) += 3;
1097 return (0);
1098 }
1099 } else {
1100 if (ip[0] == DT_OP_XOR_EAX_0 && ip[1] == DT_OP_XOR_EAX_1 &&
1101 (ip[2] == DT_OP_NOP || ip[2] == DT_OP_RET) &&
1102 ip[3] == DT_OP_NOP && ip[4] == DT_OP_NOP) {
1103 (*off) += 2;
1104 return (0);
1105 }
1106 }
1107
1108 /*
1109 * We expect either a call instrution with a 32-bit displacement or a
1110 * jmp instruction with a 32-bit displacement acting as a tail-call.
1111 */
1112 if (ip[0] != DT_OP_CALL && ip[0] != DT_OP_JMP32) {
1113 dt_dprintf("found %x instead of a call or jmp instruction at "
1114 "%llx\n", ip[0], (u_longlong_t)rela->r_offset);
1115 return (-1);
1116 }
1117
1118 ret = (ip[0] == DT_OP_JMP32) ? DT_OP_RET : DT_OP_NOP;
1119
1120 /*
1121 * Establish the instruction sequence -- all nops for probes, and an
1122 * instruction to clear the return value register (%eax/%rax) followed
1123 * by nops for is-enabled probes. For is-enabled probes, we advance
1124 * the offset to the first nop. This isn't stricly necessary but makes
1125 * for more readable disassembly when the probe is enabled.
1126 */
1127 if (!isenabled) {
1128 ip[0] = ret;
1129 ip[1] = DT_OP_NOP;
1130 ip[2] = DT_OP_NOP;
1131 ip[3] = DT_OP_NOP;
1132 ip[4] = DT_OP_NOP;
1133 } else if (dtp->dt_oflags & DTRACE_O_LP64) {
1134 ip[0] = DT_OP_REX_RAX;
1135 ip[1] = DT_OP_XOR_EAX_0;
1136 ip[2] = DT_OP_XOR_EAX_1;
1137 ip[3] = ret;
1138 ip[4] = DT_OP_NOP;
1139 (*off) += 3;
1140 } else {
1141 ip[0] = DT_OP_XOR_EAX_0;
1142 ip[1] = DT_OP_XOR_EAX_1;
1143 ip[2] = ret;
1144 ip[3] = DT_OP_NOP;
1145 ip[4] = DT_OP_NOP;
1146 (*off) += 2;
1147 }
1148
1149 return (0);
1150}
1151
1152#else
1153#error unknown ISA
1154#endif
1155
1156/*PRINTFLIKE5*/
1157static int
1158dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs,
1159 const char *format, ...)
1160{
1161 va_list ap;
1162 dt_link_pair_t *pair;
1163
1164 va_start(ap, format);
1165 dt_set_errmsg(dtp, NULL, NULL, NULL, 0, format, ap);
1166 va_end(ap);
1167
1168 if (elf != NULL)
1169 (void) elf_end(elf);
1170
1171 if (fd >= 0)
1172 (void) close(fd);
1173
1174 while ((pair = bufs) != NULL) {
1175 bufs = pair->dlp_next;
1176 dt_free(dtp, pair->dlp_str);
1177 dt_free(dtp, pair->dlp_sym);
1178 dt_free(dtp, pair);
1179 }
1180
1181 return (dt_set_errno(dtp, EDT_COMPILER));
1182}
1183
1184static int
1185process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp)
1186{
1187 static const char dt_prefix[] = "__dtrace";
1188 static const char dt_enabled[] = "enabled";
1189 static const char dt_symprefix[] = "$dtrace";
1190 static const char dt_symfmt[] = "%s%ld.%s";
1191 int fd, i, ndx, eprobe, mod = 0;
1192 Elf *elf = NULL;
1193 GElf_Ehdr ehdr;
1194 Elf_Scn *scn_rel, *scn_sym, *scn_str, *scn_tgt;
1195 Elf_Data *data_rel, *data_sym, *data_str, *data_tgt;
1196 GElf_Shdr shdr_rel, shdr_sym, shdr_str, shdr_tgt;
1197 GElf_Sym rsym, fsym, dsym;
1198 GElf_Rela rela;
1199 char *s, *p, *r;
1200 char pname[DTRACE_PROVNAMELEN];
1201 dt_provider_t *pvp;
1202 dt_probe_t *prp;
1203 uint32_t off, eclass, emachine1, emachine2;
1204 size_t symsize, nsym, isym, istr, len;
1205 key_t objkey;
1206 dt_link_pair_t *pair, *bufs = NULL;
1207 dt_strtab_t *strtab;
1208
1209 if ((fd = open64(obj, O_RDWR)) == -1) {
1210 return (dt_link_error(dtp, elf, fd, bufs,
1211 "failed to open %s: %s", obj, strerror(errno)));
1212 }
1213
1214 if ((elf = elf_begin(fd, ELF_C_RDWR, NULL)) == NULL) {
1215 return (dt_link_error(dtp, elf, fd, bufs,
1216 "failed to process %s: %s", obj, elf_errmsg(elf_errno())));
1217 }
1218
1219 switch (elf_kind(elf)) {
1220 case ELF_K_ELF:
1221 break;
1222 case ELF_K_AR:
1223 return (dt_link_error(dtp, elf, fd, bufs, "archives are not "
1224 "permitted; use the contents of the archive instead: %s",
1225 obj));
1226 default:
1227 return (dt_link_error(dtp, elf, fd, bufs,
1228 "invalid file type: %s", obj));
1229 }
1230
1231 if (gelf_getehdr(elf, &ehdr) == NULL) {
1232 return (dt_link_error(dtp, elf, fd, bufs, "corrupt file: %s",
1233 obj));
1234 }
1235
1236 if (dtp->dt_oflags & DTRACE_O_LP64) {
1237 eclass = ELFCLASS64;
1238#if defined(__ia64__)
1239 emachine1 = emachine2 = EM_IA_64;
1240#elif defined(__mips__)
1241 emachine1 = emachine2 = EM_MIPS;
1242#elif defined(__powerpc__)
1243 emachine1 = emachine2 = EM_PPC64;
1244#elif defined(__sparc)
1245 emachine1 = emachine2 = EM_SPARCV9;
1246#elif defined(__i386) || defined(__amd64)
1247 emachine1 = emachine2 = EM_AMD64;
1248#endif
1249 symsize = sizeof (Elf64_Sym);
1250 } else {
1251 eclass = ELFCLASS32;
1252#if defined(__arm__)
1253 emachine1 = emachine2 = EM_ARM;
1254#elif defined(__mips__)
1255 emachine1 = emachine2 = EM_MIPS;
1256#elif defined(__powerpc__)
1257 emachine1 = emachine2 = EM_PPC;
1258#elif defined(__sparc)
1259 emachine1 = EM_SPARC;
1260 emachine2 = EM_SPARC32PLUS;
1261#elif defined(__i386) || defined(__amd64) || defined(__ia64__)
1262 emachine1 = emachine2 = EM_386;
1263#endif
1264 symsize = sizeof (Elf32_Sym);
1265 }
1266
1267 if (ehdr.e_ident[EI_CLASS] != eclass) {
1268 return (dt_link_error(dtp, elf, fd, bufs,
1269 "incorrect ELF class for object file: %s", obj));
1270 }
1271
1272 if (ehdr.e_machine != emachine1 && ehdr.e_machine != emachine2) {
1273 return (dt_link_error(dtp, elf, fd, bufs,
1274 "incorrect ELF machine type for object file: %s", obj));
1275 }
1276
1277 /*
1278 * We use this token as a relatively unique handle for this file on the
1279 * system in order to disambiguate potential conflicts between files of
1280 * the same name which contain identially named local symbols.
1281 */
1282 if ((objkey = ftok(obj, 0)) == (key_t)-1) {
1283 return (dt_link_error(dtp, elf, fd, bufs,
1284 "failed to generate unique key for object file: %s", obj));
1285 }
1286
1287 scn_rel = NULL;
1288 while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) {
1289 if (gelf_getshdr(scn_rel, &shdr_rel) == NULL)
1290 goto err;
1291
1292 /*
1293 * Skip any non-relocation sections.
1294 */
1295 if (shdr_rel.sh_type != SHT_RELA && shdr_rel.sh_type != SHT_REL)
1296 continue;
1297
1298 if ((data_rel = elf_getdata(scn_rel, NULL)) == NULL)
1299 goto err;
1300
1301 /*
1302 * Grab the section, section header and section data for the
1303 * symbol table that this relocation section references.
1304 */
1305 if ((scn_sym = elf_getscn(elf, shdr_rel.sh_link)) == NULL ||
1306 gelf_getshdr(scn_sym, &shdr_sym) == NULL ||
1307 (data_sym = elf_getdata(scn_sym, NULL)) == NULL)
1308 goto err;
1309
1310 /*
1311 * Ditto for that symbol table's string table.
1312 */
1313 if ((scn_str = elf_getscn(elf, shdr_sym.sh_link)) == NULL ||
1314 gelf_getshdr(scn_str, &shdr_str) == NULL ||
1315 (data_str = elf_getdata(scn_str, NULL)) == NULL)
1316 goto err;
1317
1318 /*
1319 * Grab the section, section header and section data for the
1320 * target section for the relocations. For the relocations
1321 * we're looking for -- this will typically be the text of the
1322 * object file.
1323 */
1324 if ((scn_tgt = elf_getscn(elf, shdr_rel.sh_info)) == NULL ||
1325 gelf_getshdr(scn_tgt, &shdr_tgt) == NULL ||
1326 (data_tgt = elf_getdata(scn_tgt, NULL)) == NULL)
1327 goto err;
1328
1329 /*
1330 * We're looking for relocations to symbols matching this form:
1331 *
1332 * __dtrace[enabled]_<prov>___<probe>
1333 *
1334 * For the generated object, we need to record the location
1335 * identified by the relocation, and create a new relocation
1336 * in the generated object that will be resolved at link time
1337 * to the location of the function in which the probe is
1338 * embedded. In the target object, we change the matched symbol
1339 * so that it will be ignored at link time, and we modify the
1340 * target (text) section to replace the call instruction with
1341 * one or more nops.
1342 *
1343 * If the function containing the probe is locally scoped
1344 * (static), we create an alias used by the relocation in the
1345 * generated object. The alias, a new symbol, will be global
1346 * (so that the relocation from the generated object can be
1347 * resolved), and hidden (so that it is converted to a local
1348 * symbol at link time). Such aliases have this form:
1349 *
1350 * $dtrace<key>.<function>
1351 *
1352 * We take a first pass through all the relocations to
1353 * populate our string table and count the number of extra
1354 * symbols we'll require.
1355 */
1356 strtab = dt_strtab_create(1);
1357 nsym = 0;
1358 isym = data_sym->d_size / symsize;
1359 istr = data_str->d_size;
1360
1361 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) {
1362
1363 if (shdr_rel.sh_type == SHT_RELA) {
1364 if (gelf_getrela(data_rel, i, &rela) == NULL)
1365 continue;
1366 } else {
1367 GElf_Rel rel;
1368 if (gelf_getrel(data_rel, i, &rel) == NULL)
1369 continue;
1370 rela.r_offset = rel.r_offset;
1371 rela.r_info = rel.r_info;
1372 rela.r_addend = 0;
1373 }
1374
1375 if (gelf_getsym(data_sym, GELF_R_SYM(rela.r_info),
1376 &rsym) == NULL) {
1377 dt_strtab_destroy(strtab);
1378 goto err;
1379 }
1380
1381 s = (char *)data_str->d_buf + rsym.st_name;
1382
1383 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0)
1384 continue;
1385
1386 if (dt_symtab_lookup(data_sym, isym, rela.r_offset,
1387 shdr_rel.sh_info, &fsym) != 0) {
1388 dt_strtab_destroy(strtab);
1389 goto err;
1390 }
1391
1392 if (GELF_ST_BIND(fsym.st_info) != STB_LOCAL)
1393 continue;
1394
1395 if (fsym.st_name > data_str->d_size) {
1396 dt_strtab_destroy(strtab);
1397 goto err;
1398 }
1399
1400 s = (char *)data_str->d_buf + fsym.st_name;
1401
1402 /*
1403 * If this symbol isn't of type function, we've really
1404 * driven off the rails or the object file is corrupt.
1405 */
1406 if (GELF_ST_TYPE(fsym.st_info) != STT_FUNC) {
1407 dt_strtab_destroy(strtab);
1408 return (dt_link_error(dtp, elf, fd, bufs,
1409 "expected %s to be of type function", s));
1410 }
1411
1412 len = snprintf(NULL, 0, dt_symfmt, dt_symprefix,
1413 objkey, s) + 1;
1414 if ((p = dt_alloc(dtp, len)) == NULL) {
1415 dt_strtab_destroy(strtab);
1416 goto err;
1417 }
1418 (void) snprintf(p, len, dt_symfmt, dt_symprefix,
1419 objkey, s);
1420
1421 if (dt_strtab_index(strtab, p) == -1) {
1422 nsym++;
1423 (void) dt_strtab_insert(strtab, p);
1424 }
1425
1426 dt_free(dtp, p);
1427 }
1428
1429 /*
1430 * If needed, allocate the additional space for the symbol
1431 * table and string table copying the old data into the new
1432 * buffers, and marking the buffers as dirty. We inject those
1433 * newly allocated buffers into the libelf data structures, but
1434 * are still responsible for freeing them once we're done with
1435 * the elf handle.
1436 */
1437 if (nsym > 0) {
1438 /*
1439 * The first byte of the string table is reserved for
1440 * the \0 entry.
1441 */
1442 len = dt_strtab_size(strtab) - 1;
1443
1444 assert(len > 0);
1445 assert(dt_strtab_index(strtab, "") == 0);
1446
1447 dt_strtab_destroy(strtab);
1448
1449 if ((pair = dt_alloc(dtp, sizeof (*pair))) == NULL)
1450 goto err;
1451
1452 if ((pair->dlp_str = dt_alloc(dtp, data_str->d_size +
1453 len)) == NULL) {
1454 dt_free(dtp, pair);
1455 goto err;
1456 }
1457
1458 if ((pair->dlp_sym = dt_alloc(dtp, data_sym->d_size +
1459 nsym * symsize)) == NULL) {
1460 dt_free(dtp, pair->dlp_str);
1461 dt_free(dtp, pair);
1462 goto err;
1463 }
1464
1465 pair->dlp_next = bufs;
1466 bufs = pair;
1467
1468 bcopy(data_str->d_buf, pair->dlp_str, data_str->d_size);
1469 data_str->d_buf = pair->dlp_str;
1470 data_str->d_size += len;
1471 (void) elf_flagdata(data_str, ELF_C_SET, ELF_F_DIRTY);
1472
1473 shdr_str.sh_size += len;
1474 (void) gelf_update_shdr(scn_str, &shdr_str);
1475
1476 bcopy(data_sym->d_buf, pair->dlp_sym, data_sym->d_size);
1477 data_sym->d_buf = pair->dlp_sym;
1478 data_sym->d_size += nsym * symsize;
1479 (void) elf_flagdata(data_sym, ELF_C_SET, ELF_F_DIRTY);
1480
1481 shdr_sym.sh_size += nsym * symsize;
1482 (void) gelf_update_shdr(scn_sym, &shdr_sym);
1483
1484 nsym += isym;
1485 } else {
1486 dt_strtab_destroy(strtab);
1487 }
1488
1489 /*
1490 * Now that the tables have been allocated, perform the
1491 * modifications described above.
1492 */
1493 for (i = 0; i < shdr_rel.sh_size / shdr_rel.sh_entsize; i++) {
1494
1495 if (shdr_rel.sh_type == SHT_RELA) {
1496 if (gelf_getrela(data_rel, i, &rela) == NULL)
1497 continue;
1498 } else {
1499 GElf_Rel rel;
1500 if (gelf_getrel(data_rel, i, &rel) == NULL)
1501 continue;
1502 rela.r_offset = rel.r_offset;
1503 rela.r_info = rel.r_info;
1504 rela.r_addend = 0;
1505 }
1506
1507 ndx = GELF_R_SYM(rela.r_info);
1508
1509 if (gelf_getsym(data_sym, ndx, &rsym) == NULL ||
1510 rsym.st_name > data_str->d_size)
1511 goto err;
1512
1513 s = (char *)data_str->d_buf + rsym.st_name;
1514
1515 if (strncmp(s, dt_prefix, sizeof (dt_prefix) - 1) != 0)
1516 continue;
1517
1518 s += sizeof (dt_prefix) - 1;
1519
1520 /*
1521 * Check to see if this is an 'is-enabled' check as
1522 * opposed to a normal probe.
1523 */
1524 if (strncmp(s, dt_enabled,
1525 sizeof (dt_enabled) - 1) == 0) {
1526 s += sizeof (dt_enabled) - 1;
1527 eprobe = 1;
1528 *eprobesp = 1;
1529 dt_dprintf("is-enabled probe\n");
1530 } else {
1531 eprobe = 0;
1532 dt_dprintf("normal probe\n");
1533 }
1534
1535 if (*s++ != '_')
1536 goto err;
1537
1538 if ((p = strstr(s, "___")) == NULL ||
1539 p - s >= sizeof (pname))
1540 goto err;
1541
1542 bcopy(s, pname, p - s);
1543 pname[p - s] = '\0';
1544
1545 p = strhyphenate(p + 3); /* strlen("___") */
1546
1547 if (dt_symtab_lookup(data_sym, isym, rela.r_offset,
1548 shdr_rel.sh_info, &fsym) != 0)
1549 goto err;
1550
1551 if (fsym.st_name > data_str->d_size)
1552 goto err;
1553
1554 assert(GELF_ST_TYPE(fsym.st_info) == STT_FUNC);
1555
1556 /*
1557 * If a NULL relocation name is passed to
1558 * dt_probe_define(), the function name is used for the
1559 * relocation. The relocation needs to use a mangled
1560 * name if the symbol is locally scoped; the function
1561 * name may need to change if we've found the global
1562 * alias for the locally scoped symbol (we prefer
1563 * global symbols to locals in dt_symtab_lookup()).
1564 */
1565 s = (char *)data_str->d_buf + fsym.st_name;
1566 r = NULL;
1567
1568 if (GELF_ST_BIND(fsym.st_info) == STB_LOCAL) {
1569 dsym = fsym;
1570 dsym.st_name = istr;
1571 dsym.st_info = GELF_ST_INFO(STB_GLOBAL,
1572 STT_FUNC);
1573 dsym.st_other =
1574 ELF64_ST_VISIBILITY(STV_ELIMINATE);
1575 (void) gelf_update_sym(data_sym, isym, &dsym);
1576
1577 r = (char *)data_str->d_buf + istr;
1578 istr += 1 + sprintf(r, dt_symfmt,
1579 dt_symprefix, objkey, s);
1580 isym++;
1581 assert(isym <= nsym);
1582
1583 } else if (strncmp(s, dt_symprefix,
1584 strlen(dt_symprefix)) == 0) {
1585 r = s;
1586 if ((s = strchr(s, '.')) == NULL)
1587 goto err;
1588 s++;
1589 }
1590
1591 if ((pvp = dt_provider_lookup(dtp, pname)) == NULL) {
1592 return (dt_link_error(dtp, elf, fd, bufs,
1593 "no such provider %s", pname));
1594 }
1595
1596 if ((prp = dt_probe_lookup(pvp, p)) == NULL) {
1597 return (dt_link_error(dtp, elf, fd, bufs,
1598 "no such probe %s", p));
1599 }
1600
1601 assert(fsym.st_value <= rela.r_offset);
1602
1603 off = rela.r_offset - fsym.st_value;
1604 if (dt_modtext(dtp, data_tgt->d_buf, eprobe,
1605 &rela, &off) != 0)
1606 goto err;
1607
1608 if (dt_probe_define(pvp, prp, s, r, off, eprobe) != 0) {
1609 return (dt_link_error(dtp, elf, fd, bufs,
1610 "failed to allocate space for probe"));
1611 }
1612#if !defined(sun)
1613 /*
1614 * Our linker doesn't understand the SUNW_IGNORE ndx and
1615 * will try to use this relocation when we build the
1616 * final executable. Since we are done processing this
1617 * relocation, mark it as inexistant and let libelf
1618 * remove it from the file.
1619 * If this wasn't done, we would have garbage added to
1620 * the executable file as the symbol is going to be
1621 * change from UND to ABS.
1622 */
1623 rela.r_offset = 0;
1624 rela.r_info = 0;
1625 rela.r_addend = 0;
1626 (void) gelf_update_rela(data_rel, i, &rela);
1627#endif
1628
1629 mod = 1;
1630 (void) elf_flagdata(data_tgt, ELF_C_SET, ELF_F_DIRTY);
1631
1632 /*
1633 * This symbol may already have been marked to
1634 * be ignored by another relocation referencing
1635 * the same symbol or if this object file has
1636 * already been processed by an earlier link
1637 * invocation.
1638 */
1639#if !defined(sun)
1640#define SHN_SUNW_IGNORE SHN_ABS
1641#endif
1642 if (rsym.st_shndx != SHN_SUNW_IGNORE) {
1643 rsym.st_shndx = SHN_SUNW_IGNORE;
1644 (void) gelf_update_sym(data_sym, ndx, &rsym);
1645 }
1646 }
1647 }
1648
1649 if (mod && elf_update(elf, ELF_C_WRITE) == -1)
1650 goto err;
1651
1652 (void) elf_end(elf);
1653 (void) close(fd);
1654
1655#if !defined(sun)
1656 if (nsym > 0)
1657#endif
1658 while ((pair = bufs) != NULL) {
1659 bufs = pair->dlp_next;
1660 dt_free(dtp, pair->dlp_str);
1661 dt_free(dtp, pair->dlp_sym);
1662 dt_free(dtp, pair);
1663 }
1664
1665 return (0);
1666
1667err:
1668 return (dt_link_error(dtp, elf, fd, bufs,
1669 "an error was encountered while processing %s", obj));
1670}
1671
1672int
1673dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags,
1674 const char *file, int objc, char *const objv[])
1675{
1676#if !defined(sun)
1677 char tfile[PATH_MAX];
1678 Elf *e;
1679 Elf_Scn *scn;
1680 Elf_Data *data;
1681 GElf_Shdr shdr;
1682 int efd;
1683 size_t stridx;
1684 unsigned char *buf;
1685 char *s;
1686 int loc;
1687 GElf_Ehdr ehdr;
1688 Elf_Scn *scn0;
1689 GElf_Shdr shdr0;
1690 uint64_t off, rc;
1691#endif
1692 char drti[PATH_MAX];
1693 dof_hdr_t *dof;
1694 int fd, status, i, cur;
1695 char *cmd, tmp;
1696 size_t len;
1697 int eprobes = 0, ret = 0;
1698
1699#if !defined(sun)
1700 if (access(file, R_OK) == 0) {
1701 fprintf(stderr, "dtrace: target object (%s) already exists. "
1702 "Please remove the target\ndtrace: object and rebuild all "
1703 "the source objects if you wish to run the DTrace\n"
1704 "dtrace: linking process again\n", file);
1705 /*
1706 * Several build infrastructures run DTrace twice (e.g.
1707 * postgres) and we don't want the build to fail. Return
1708 * 0 here since this isn't really a fatal error.
1709 */
1710 return (0);
1711 }
1712 /* XXX Should get a temp file name here. */
1713 snprintf(tfile, sizeof(tfile), "%s.tmp", file);
1714#endif
1715
1716 /*
1717 * A NULL program indicates a special use in which we just link
1718 * together a bunch of object files specified in objv and then
1719 * unlink(2) those object files.
1720 */
1721 if (pgp == NULL) {
1722 const char *fmt = "%s -o %s -r";
1723
1724 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file) + 1;
1725
1726 for (i = 0; i < objc; i++)
1727 len += strlen(objv[i]) + 1;
1728
1729 cmd = alloca(len);
1730
1731 cur = snprintf(cmd, len, fmt, dtp->dt_ld_path, file);
1732
1733 for (i = 0; i < objc; i++)
1734 cur += snprintf(cmd + cur, len - cur, " %s", objv[i]);
1735
1736 if ((status = system(cmd)) == -1) {
1737 return (dt_link_error(dtp, NULL, -1, NULL,
1738 "failed to run %s: %s", dtp->dt_ld_path,
1739 strerror(errno)));
1740 }
1741
1742 if (WIFSIGNALED(status)) {
1743 return (dt_link_error(dtp, NULL, -1, NULL,
1744 "failed to link %s: %s failed due to signal %d",
1745 file, dtp->dt_ld_path, WTERMSIG(status)));
1746 }
1747
1748 if (WEXITSTATUS(status) != 0) {
1749 return (dt_link_error(dtp, NULL, -1, NULL,
1750 "failed to link %s: %s exited with status %d\n",
1751 file, dtp->dt_ld_path, WEXITSTATUS(status)));
1752 }
1753
1754 for (i = 0; i < objc; i++) {
1755 if (strcmp(objv[i], file) != 0)
1756 (void) unlink(objv[i]);
1757 }
1758
1759 return (0);
1760 }
1761
1762 for (i = 0; i < objc; i++) {
1763 if (process_obj(dtp, objv[i], &eprobes) != 0)
1764 return (-1); /* errno is set for us */
1765 }
1766
1767 /*
1768 * If there are is-enabled probes then we need to force use of DOF
1769 * version 2.
1770 */
1771 if (eprobes && pgp->dp_dofversion < DOF_VERSION_2)
1772 pgp->dp_dofversion = DOF_VERSION_2;
1773
1774 if ((dof = dtrace_dof_create(dtp, pgp, dflags)) == NULL)
1775 return (-1); /* errno is set for us */
1776
1777#if defined(sun)
1778 /*
1779 * Create a temporary file and then unlink it if we're going to
1780 * combine it with drti.o later. We can still refer to it in child
1781 * processes as /dev/fd/<fd>.
1782 */
1783 if ((fd = open64(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1) {
1784 return (dt_link_error(dtp, NULL, -1, NULL,
1785 "failed to open %s: %s", file, strerror(errno)));
1786 }
1787#else
1788 if ((fd = open(tfile, O_RDWR | O_CREAT | O_TRUNC, 0666)) == -1)
1789 return (dt_link_error(dtp, NULL, -1, NULL,
1790 "failed to open %s: %s", tfile, strerror(errno)));
1791#endif
1792
1793 /*
1794 * If -xlinktype=DOF has been selected, just write out the DOF.
1795 * Otherwise proceed to the default of generating and linking ELF.
1796 */
1797 switch (dtp->dt_linktype) {
1798 case DT_LTYP_DOF:
1799 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz)
1800 ret = errno;
1801
1802 if (close(fd) != 0 && ret == 0)
1803 ret = errno;
1804
1805 if (ret != 0) {
1806 return (dt_link_error(dtp, NULL, -1, NULL,
1807 "failed to write %s: %s", file, strerror(ret)));
1808 }
1809
1810 return (0);
1811
1812 case DT_LTYP_ELF:
1813 break; /* fall through to the rest of dtrace_program_link() */
1814
1815 default:
1816 return (dt_link_error(dtp, NULL, -1, NULL,
1817 "invalid link type %u\n", dtp->dt_linktype));
1818 }
1819
1820
1821#if defined(sun)
1822 if (!dtp->dt_lazyload)
1823 (void) unlink(file);
1824#endif
1825
1826#if defined(sun)
1827 if (dtp->dt_oflags & DTRACE_O_LP64)
1828 status = dump_elf64(dtp, dof, fd);
1829 else
1830 status = dump_elf32(dtp, dof, fd);
1831
1832 if (status != 0 || lseek(fd, 0, SEEK_SET) != 0) {
1833#else
1834 /* We don't write the ELF header, just the DOF section */
1835 if (dt_write(dtp, fd, dof, dof->dofh_filesz) < dof->dofh_filesz) {
1836#endif
1837 return (dt_link_error(dtp, NULL, -1, NULL,
1838 "failed to write %s: %s", file, strerror(errno)));
1839 }
1840
1841 if (!dtp->dt_lazyload) {
1842#if defined(sun)
1843 const char *fmt = "%s -o %s -r -Blocal -Breduce /dev/fd/%d %s";
1844
1845 if (dtp->dt_oflags & DTRACE_O_LP64) {
1846 (void) snprintf(drti, sizeof (drti),
1847 "%s/64/drti.o", _dtrace_libdir);
1848 } else {
1849 (void) snprintf(drti, sizeof (drti),
1850 "%s/drti.o", _dtrace_libdir);
1851 }
1852
1853 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, fd,
1854 drti) + 1;
1855
1856 cmd = alloca(len);
1857
1858 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file, fd, drti);
1859#else
1860 const char *fmt = "%s -o %s -r %s";
1861
1862#if defined(__amd64__)
1863 /*
1864 * Arches which default to 64-bit need to explicitly use
1865 * the 32-bit library path.
1866 */
1867 int use_32 = !(dtp->dt_oflags & DTRACE_O_LP64);
1868#else
1869 /*
1870 * Arches which are 32-bit only just use the normal
1871 * library path.
1872 */
1873 int use_32 = 0;
1874#endif
1875
1876 (void) snprintf(drti, sizeof (drti), "/usr/lib%s/dtrace/drti.o",
1877 use_32 ? "32":"");
1878
1879 len = snprintf(&tmp, 1, fmt, dtp->dt_ld_path, file, tfile,
1880 drti) + 1;
1881
1882#if !defined(sun)
1883 len *= 2;
1884#endif
1885 cmd = alloca(len);
1886
1887 (void) snprintf(cmd, len, fmt, dtp->dt_ld_path, file,
1888 drti);
1889#endif
1890 if ((status = system(cmd)) == -1) {
1891 ret = dt_link_error(dtp, NULL, -1, NULL,
1892 "failed to run %s: %s", dtp->dt_ld_path,
1893 strerror(errno));
1894 goto done;
1895 }
1896
1897 if (WIFSIGNALED(status)) {
1898 ret = dt_link_error(dtp, NULL, -1, NULL,
1899 "failed to link %s: %s failed due to signal %d",
1900 file, dtp->dt_ld_path, WTERMSIG(status));
1901 goto done;
1902 }
1903
1904 if (WEXITSTATUS(status) != 0) {
1905 ret = dt_link_error(dtp, NULL, -1, NULL,
1906 "failed to link %s: %s exited with status %d\n",
1907 file, dtp->dt_ld_path, WEXITSTATUS(status));
1908 goto done;
1909 }
1910#if !defined(sun)
1911#define BROKEN_LIBELF
1912 /*
1913 * FreeBSD's ld(1) is not instructed to interpret and add
1914 * correctly the SUNW_dof section present in tfile.
1915 * We use libelf to add this section manually and hope the next
1916 * ld invocation won't remove it.
1917 */
1918 elf_version(EV_CURRENT);
1919 if ((efd = open(file, O_RDWR, 0)) < 0) {
1920 ret = dt_link_error(dtp, NULL, -1, NULL,
1921 "failed to open file %s: %s",
1922 file, strerror(errno));
1923 goto done;
1924 }
1925 if ((e = elf_begin(efd, ELF_C_RDWR, NULL)) == NULL) {
1926 close(efd);
1927 ret = dt_link_error(dtp, NULL, -1, NULL,
1928 "failed to open elf file: %s",
1929 elf_errmsg(elf_errno()));
1930 goto done;
1931 }
1932 /*
1933 * Add the string '.SUWN_dof' to the shstrtab section.
1934 */
1935#ifdef BROKEN_LIBELF
1936 elf_flagelf(e, ELF_C_SET, ELF_F_LAYOUT);
1937#endif
1938 elf_getshdrstrndx(e, &stridx);
1939 scn = elf_getscn(e, stridx);
1940 gelf_getshdr(scn, &shdr);
1941 data = elf_newdata(scn);
1942 data->d_off = shdr.sh_size;
1943 data->d_buf = ".SUNW_dof";
1944 data->d_size = 10;
1945 data->d_type = ELF_T_BYTE;
1946 loc = shdr.sh_size;
1947 shdr.sh_size += data->d_size;
1948 gelf_update_shdr(scn, &shdr);
1949#ifdef BROKEN_LIBELF
1950 off = shdr.sh_offset;
1951 rc = shdr.sh_offset + shdr.sh_size;
1952 gelf_getehdr(e, &ehdr);
1953 if (ehdr.e_shoff > off) {
1954 off = ehdr.e_shoff + ehdr.e_shnum * ehdr.e_shentsize;
1955 rc = roundup(rc, 8);
1956 ehdr.e_shoff = rc;
1957 gelf_update_ehdr(e, &ehdr);
1958 rc += ehdr.e_shnum * ehdr.e_shentsize;
1959 }
1960 for (;;) {
1961 scn0 = NULL;
1962 scn = NULL;
1963 while ((scn = elf_nextscn(e, scn)) != NULL) {
1964 gelf_getshdr(scn, &shdr);
1965 if (shdr.sh_type == SHT_NOBITS ||
1966 shdr.sh_offset < off)
1967 continue;
1968 /* Find the immediately adjcent section. */
1969 if (scn0 == NULL ||
1970 shdr.sh_offset < shdr0.sh_offset) {
1971 scn0 = scn;
1972 gelf_getshdr(scn0, &shdr0);
1973 }
1974 }
1975 if (scn0 == NULL)
1976 break;
1977 /* Load section data to work around another bug */
1978 elf_getdata(scn0, NULL);
1979 /* Update section header, assure section alignment */
1980 off = shdr0.sh_offset + shdr0.sh_size;
1981 rc = roundup(rc, shdr0.sh_addralign);
1982 shdr0.sh_offset = rc;
1983 gelf_update_shdr(scn0, &shdr0);
1984 rc += shdr0.sh_size;
1985 }
1986 if (elf_update(e, ELF_C_WRITE) < 0) {
1987 ret = dt_link_error(dtp, NULL, -1, NULL,
1988 "failed to add append the shstrtab section: %s",
1989 elf_errmsg(elf_errno()));
1990 elf_end(e);
1991 close(efd);
1992 goto done;
1993 }
1994 elf_end(e);
1995 e = elf_begin(efd, ELF_C_RDWR, NULL);
1996#endif
1997 /*
1998 * Construct the .SUNW_dof section.
1999 */
2000 scn = elf_newscn(e);
2001 data = elf_newdata(scn);
2002 buf = mmap(NULL, dof->dofh_filesz, PROT_READ, MAP_SHARED,
2003 fd, 0);
2004 if (buf == MAP_FAILED) {
2005 ret = dt_link_error(dtp, NULL, -1, NULL,
2006 "failed to mmap buffer %s", strerror(errno));
2007 elf_end(e);
2008 close(efd);
2009 goto done;
2010 }
2011 data->d_buf = buf;
2012 data->d_align = 4;
2013 data->d_size = dof->dofh_filesz;
2014 data->d_version = EV_CURRENT;
2015 gelf_getshdr(scn, &shdr);
2016 shdr.sh_name = loc;
2017 shdr.sh_flags = SHF_ALLOC;
2018 /*
2019 * Actually this should be SHT_SUNW_dof, but FreeBSD's ld(1)
2020 * will remove this 'unknown' section when we try to create an
2021 * executable using the object we are modifying, so we stop
2022 * playing by the rules and use SHT_PROGBITS.
2023 * Also, note that our drti has modifications to handle this.
2024 */
2025 shdr.sh_type = SHT_PROGBITS;
2026 shdr.sh_addralign = 4;
2027 gelf_update_shdr(scn, &shdr);
2028 if (elf_update(e, ELF_C_WRITE) < 0) {
2029 ret = dt_link_error(dtp, NULL, -1, NULL,
2030 "failed to add the SUNW_dof section: %s",
2031 elf_errmsg(elf_errno()));
2032 munmap(buf, dof->dofh_filesz);
2033 elf_end(e);
2034 close(efd);
2035 goto done;
2036 }
2037 munmap(buf, dof->dofh_filesz);
2038 elf_end(e);
2039 close(efd);
2040#endif
2041 (void) close(fd); /* release temporary file */
2042 } else {
2043 (void) close(fd);
2044 }
2045
2046done:
2047 dtrace_dof_destroy(dtp, dof);
2048
2049#if !defined(sun)
2050 unlink(tfile);
2051#endif
2052 return (ret);
2053}