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 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#pragma ident	"%Z%%M%	%I%	%E% SMI"
27
28/*
29 * Routines used to read stabs data from a file, and to build a tdata structure
30 * based on the interesting parts of that data.
31 */
32
33#include <stdio.h>
34#include <stdlib.h>
35#include <fcntl.h>
36#include <unistd.h>
37#include <assert.h>
38#include <string.h>
39#include <libgen.h>
40#include <errno.h>
41#include <sys/types.h>
42#include <sys/param.h>
43
44#include "ctftools.h"
45#include "list.h"
46#include "stack.h"
47#include "memory.h"
48#include "traverse.h"
49
50char *curhdr;
51
52/*
53 * The stabs generator will sometimes reference types before they've been
54 * defined.  If this is the case, a TYPEDEF_UNRES tdesc will be generated.
55 * Note that this is different from a forward declaration, in which the
56 * stab is defined, but is defined as something that doesn't exist yet.
57 * When we have read all of the stabs from the file, we can go back and
58 * fix up all of the unresolved types.  We should be able to fix all of them.
59 */
60/*ARGSUSED2*/
61static int
62resolve_tou_node(tdesc_t *node, tdesc_t **nodep, void *private __unused)
63{
64	tdesc_t *new;
65
66	debug(3, "Trying to resolve %s (%d)\n", tdesc_name(node), node->t_id);
67	new = lookup(node->t_id);
68
69	if (new == NULL) {
70		terminate("Couldn't resolve type %d\n", node->t_id);
71	}
72
73	debug(3, " Resolving to %d\n", new->t_id);
74
75	*nodep = new;
76
77	return (1);
78}
79
80/*ARGSUSED*/
81static int
82resolve_fwd_node(tdesc_t *node, tdesc_t **nodep, void *private __unused)
83{
84	tdesc_t *new = lookupname(node->t_name);
85
86	debug(3, "Trying to unforward %s (%d)\n", tdesc_name(node), node->t_id);
87
88	if (!new || (new->t_type != STRUCT && new->t_type != UNION))
89		return (0);
90
91	debug(3, " Unforwarded to %d\n", new->t_id);
92
93	*nodep = new;
94
95	return (1);
96}
97
98static tdtrav_cb_f resolve_cbs[] = {
99	NULL,
100	NULL,			/* intrinsic */
101	NULL,			/* pointer */
102	NULL,			/* array */
103	NULL,			/* function */
104	NULL,			/* struct */
105	NULL,			/* union */
106	NULL,			/* enum */
107	resolve_fwd_node,	/* forward */
108	NULL,			/* typedef */
109	resolve_tou_node,	/* typedef unres */
110	NULL,			/* volatile */
111	NULL,			/* const */
112	NULL,			/* restrict */
113};
114
115static void
116resolve_nodes(tdata_t *td)
117{
118	debug(2, "Resolving unresolved stabs\n");
119
120	(void) iitraverse_hash(td->td_iihash, &td->td_curvgen, resolve_cbs,
121	    NULL, NULL, td);
122}
123
124static char *
125concat(char *s1, char *s2, int s2strip)
126{
127	int savelen = strlen(s2) - s2strip;
128	int newlen = (s1 ? strlen(s1) : 0) + savelen + 1;
129	char *out;
130
131	out = xrealloc(s1, newlen);
132	if (s1)
133		strncpy(out + strlen(out), s2, savelen);
134	else
135		strncpy(out, s2, savelen);
136
137	out[newlen - 1] = '\0';
138
139	return (out);
140}
141
142/*
143 * N_FUN stabs come with their arguments in promoted form.  In order to get the
144 * actual arguments, we need to wait for the N_PSYM stabs that will come towards
145 * the end of the function.  These routines free the arguments (fnarg_free) we
146 * got from the N_FUN stab and add (fnarg_add) the ones from the N_PSYM stabs.
147 */
148static void
149fnarg_add(iidesc_t *curfun, iidesc_t *arg)
150{
151	curfun->ii_nargs++;
152
153	if (curfun->ii_nargs == 1)
154		curfun->ii_args = xmalloc(sizeof (tdesc_t *) * FUNCARG_DEF);
155	else if (curfun->ii_nargs > FUNCARG_DEF) {
156		curfun->ii_args = xrealloc(curfun->ii_args,
157		    sizeof (tdesc_t *) * curfun->ii_nargs);
158	}
159
160	curfun->ii_args[curfun->ii_nargs - 1] = arg->ii_dtype;
161	arg->ii_dtype = NULL;
162}
163
164static void
165fnarg_free(iidesc_t *ii)
166{
167	ii->ii_nargs = 0;
168	free(ii->ii_args);
169	ii->ii_args = NULL;
170}
171
172/*
173 * Read the stabs from the stab ELF section, and turn them into a tdesc tree,
174 * assembled under an iidesc list.
175 */
176int
177stabs_read(tdata_t *td, Elf *elf, char *file)
178{
179	Elf_Scn *scn;
180	Elf_Data *data;
181	stab_t *stab;
182	stk_t *file_stack;
183	iidesc_t *iidescp;
184	iidesc_t *curfun = NULL;
185	char curpath[MAXPATHLEN];
186	char *curfile = NULL;
187	char *str;
188	char *fstr = NULL, *ofstr = NULL;
189	int stabidx, stabstridx;
190	int nstabs, rc, i;
191	int scope = 0;
192
193	if (!((stabidx = findelfsecidx(elf, file, ".stab.excl")) >= 0 &&
194	    (stabstridx = findelfsecidx(elf, file, ".stab.exclstr")) >= 0) &&
195	    !((stabidx = findelfsecidx(elf, file, ".stab")) >= 0 &&
196	    (stabstridx = findelfsecidx(elf, file, ".stabstr")) >= 0)) {
197		errno = ENOENT;
198		return (-1);
199	}
200
201	file_stack = stack_new(free);
202
203	stack_push(file_stack, file);
204	curhdr = file;
205
206	debug(3, "Found stabs in %d, strings in %d\n", stabidx, stabstridx);
207
208	scn = elf_getscn(elf, stabidx);
209	data = elf_rawdata(scn, NULL);
210	nstabs = data->d_size / sizeof (stab_t);
211
212	parse_init(td);
213	for (i = 0; i < nstabs; i++) {
214		stab = &((stab_t *)data->d_buf)[i];
215
216		/* We don't want any local definitions */
217		if (stab->n_type == N_LBRAC) {
218			scope++;
219			debug(3, "stab %d: opening scope (%d)\n", i + 1, scope);
220			continue;
221		} else if (stab->n_type == N_RBRAC) {
222			scope--;
223			debug(3, "stab %d: closing scope (%d)\n", i + 1, scope);
224			continue;
225		} else if (stab->n_type == N_EINCL) {
226			/*
227			 * There's a bug in the 5.2 (Taz) compilers that causes
228			 * them to emit an extra N_EINCL if there's no actual
229			 * text in the file being compiled.  To work around this
230			 * bug, we explicitly check to make sure we're not
231			 * trying to pop a stack that only has the outer scope
232			 * on it.
233			 */
234			if (stack_level(file_stack) != 1) {
235				str = (char *)stack_pop(file_stack);
236				free(str);
237				curhdr = (char *)stack_peek(file_stack);
238			}
239		}
240
241		/* We only care about a subset of the stabs */
242		if (!(stab->n_type == N_FUN || stab->n_type == N_GSYM ||
243		    stab->n_type == N_LCSYM || stab->n_type == N_LSYM ||
244		    stab->n_type == N_PSYM || stab->n_type == N_ROSYM ||
245		    stab->n_type == N_RSYM ||
246		    stab->n_type == N_STSYM || stab->n_type == N_BINCL ||
247		    stab->n_type == N_SO || stab->n_type == N_OPT))
248			continue;
249
250		if ((str = elf_strptr(elf, stabstridx,
251		    (size_t)stab->n_strx)) == NULL) {
252			terminate("%s: Can't find string at %u for stab %d\n",
253			    file, stab->n_strx, i);
254		}
255
256		if (stab->n_type == N_BINCL) {
257			curhdr = xstrdup(str);
258			stack_push(file_stack, curhdr);
259			continue;
260		} else if (stab->n_type == N_SO) {
261			if (str[strlen(str) - 1] != '/') {
262				strcpy(curpath, str);
263				curfile = basename(curpath);
264			}
265			continue;
266		} else if (stab->n_type == N_OPT) {
267			if (strcmp(str, "gcc2_compiled.") == 0) {
268				terminate("%s: GCC-generated stabs are "
269				    "unsupported. Use DWARF instead.\n", file);
270			}
271			continue;
272		}
273
274		if (str[strlen(str) - 1] == '\\') {
275			int offset = 1;
276			/*
277			 * There's a bug in the compilers that causes them to
278			 * generate \ for continuations with just -g (this is
279			 * ok), and \\ for continuations with -g -O (this is
280			 * broken).  This bug is "fixed" in the 6.2 compilers
281			 * via the elimination of continuation stabs.
282			 */
283			if (str[strlen(str) - 2] == '\\')
284				offset = 2;
285			fstr = concat(fstr, str, offset);
286			continue;
287		} else
288			fstr = concat(fstr, str, 0);
289
290		debug(3, "%4d: .stabs \"%s\", %#x, %d, %hd, %d (from %s)\n", i,
291		    fstr, stab->n_type, 0, stab->n_desc,
292		    stab->n_value, curhdr);
293
294		if (debug_level >= 3)
295			check_hash();
296
297		/*
298		 * Sometimes the compiler stutters, and emits the same stab
299		 * twice.  This is bad for the parser, which will attempt to
300		 * redefine the type IDs indicated in the stabs.  This is
301		 * compiler bug 4433511.
302		 */
303		if (ofstr && strcmp(fstr, ofstr) == 0) {
304			debug(3, "Stutter stab\n");
305			free(fstr);
306			fstr = NULL;
307			continue;
308		}
309
310		if (ofstr)
311			free(ofstr);
312		ofstr = fstr;
313
314		iidescp = NULL;
315
316		if ((rc = parse_stab(stab, fstr, &iidescp)) < 0) {
317			terminate("%s: Couldn't parse stab \"%s\" "
318			    "(source file %s)\n", file, str, curhdr);
319		}
320
321		if (rc == 0)
322			goto parse_loop_end;
323
324		/* Make sure the scope tracking is working correctly */
325		assert(stab->n_type != N_FUN || (iidescp->ii_type != II_GFUN &&
326		    iidescp->ii_type != II_SFUN) || scope == 0);
327
328		/*
329		 * The only things we care about that are in local scope are
330		 * the N_PSYM stabs.
331		 */
332		if (scope && stab->n_type != N_PSYM) {
333			if (iidescp)
334				iidesc_free(iidescp, NULL);
335			goto parse_loop_end;
336		}
337
338		switch (iidescp->ii_type) {
339		case II_SFUN:
340			iidescp->ii_owner = xstrdup(curfile);
341			/*FALLTHROUGH*/
342		case II_GFUN:
343			curfun = iidescp;
344			fnarg_free(iidescp);
345			iidesc_add(td->td_iihash, iidescp);
346			break;
347
348		case II_SVAR:
349			iidescp->ii_owner = xstrdup(curfile);
350			/*FALLTHROUGH*/
351		case II_GVAR:
352		case II_TYPE:
353		case II_SOU:
354			iidesc_add(td->td_iihash, iidescp);
355			break;
356
357		case II_PSYM:
358			fnarg_add(curfun, iidescp);
359			iidesc_free(iidescp, NULL);
360			break;
361		default:
362			aborterr("invalid ii_type %d for stab type %d",
363			    iidescp->ii_type, stab->n_type);
364		}
365
366parse_loop_end:
367		fstr = NULL;
368	}
369
370	if (ofstr)
371		free(ofstr);
372
373	resolve_nodes(td);
374	resolve_typed_bitfields();
375	parse_finish(td);
376
377	cvt_fixstabs(td);
378	cvt_fixups(td, elf_ptrsz(elf));
379
380	return (0);
381}
382