sym.c revision 323180 
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, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright (c) 1997-1999 by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include <stdio.h>
30#include <fcntl.h>
31#include <ctype.h>
32#include <string.h>
33#include <signal.h>
34#include <errno.h>
35#include <stdlib.h>
36#include <stdarg.h>
37#include <unistd.h>
38#include <limits.h>
39#include <sys/types.h>
40#include <sys/stat.h>
41
42#include <libelf.h>
43#include <link.h>
44#include <elf.h>
45#ifdef illumos
46#include <sys/machelf.h>
47
48#include <kstat.h>
49#else
50#include <sys/elf.h>
51#include <sys/param.h>
52#include <sys/module.h>
53#include <sys/linker.h>
54#endif
55#include <sys/cpuvar.h>
56
57typedef struct syment {
58	uintptr_t	addr;
59	char		*name;
60	size_t		size;
61} syment_t;
62
63static syment_t *symbol_table;
64static int nsyms, maxsyms;
65static char maxsymname[64];
66
67#ifdef illumos
68#ifdef _ELF64
69#define	elf_getshdr elf64_getshdr
70#else
71#define	elf_getshdr elf32_getshdr
72#endif
73#endif
74
75static void
76add_symbol(char *name, uintptr_t addr, size_t size)
77{
78	syment_t *sep;
79
80	if (nsyms >= maxsyms) {
81		maxsyms += 10000;
82		symbol_table = realloc(symbol_table, maxsyms * sizeof (*sep));
83		if (symbol_table == NULL) {
84			(void) fprintf(stderr, "can't allocate symbol table\n");
85			exit(3);
86		}
87	}
88	sep = &symbol_table[nsyms++];
89
90	sep->name = name;
91	sep->addr = addr;
92	sep->size = size;
93}
94
95static void
96remove_symbol(uintptr_t addr)
97{
98	int i;
99	syment_t *sep = symbol_table;
100
101	for (i = 0; i < nsyms; i++, sep++)
102		if (sep->addr == addr)
103			sep->addr = 0;
104}
105
106#ifdef illumos
107static void
108fake_up_certain_popular_kernel_symbols(void)
109{
110	kstat_ctl_t *kc;
111	kstat_t *ksp;
112	char *name;
113
114	if ((kc = kstat_open()) == NULL)
115		return;
116
117	for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
118		if (strcmp(ksp->ks_module, "cpu_info") == 0) {
119			if ((name = malloc(20)) == NULL)
120				break;
121			/*
122			 * For consistency, keep cpu[0] and toss cpu0
123			 * or any other such symbols.
124			 */
125			if (ksp->ks_instance == 0)
126				remove_symbol((uintptr_t)ksp->ks_private);
127			(void) sprintf(name, "cpu[%d]", ksp->ks_instance);
128			add_symbol(name, (uintptr_t)ksp->ks_private,
129			    sizeof (struct cpu));
130		}
131	}
132	(void) kstat_close(kc);
133}
134#else /* !illumos */
135static void
136fake_up_certain_popular_kernel_symbols(void)
137{
138	char *name;
139	uintptr_t addr;
140	int i;
141
142	/* Good for up to 256 CPUs */
143	for(i=0; i < 256;  i++) {
144		if ((name = malloc(20)) == NULL)
145			break;
146		(void) sprintf(name, "cpu[%d]", i);
147		addr = 0x01000000 + (i << 16);
148		add_symbol(name, addr, sizeof (uintptr_t));
149	}
150}
151#endif /* illumos */
152
153static int
154symcmp(const void *p1, const void *p2)
155{
156	uintptr_t a1 = ((syment_t *)p1)->addr;
157	uintptr_t a2 = ((syment_t *)p2)->addr;
158
159	if (a1 < a2)
160		return (-1);
161	if (a1 > a2)
162		return (1);
163	return (0);
164}
165
166int
167symtab_init(void)
168{
169	Elf		*elf;
170	Elf_Scn		*scn = NULL;
171	Sym		*symtab, *symp, *lastsym;
172	char		*strtab;
173	uint_t		cnt;
174	int		fd;
175	int		i;
176	int		strindex = -1;
177
178#ifndef illumos
179	if ((fd = open("/dev/ksyms", O_RDONLY)) == -1) {
180		if (errno == ENOENT && modfind("ksyms") == -1) {
181			kldload("ksyms");
182			fd = open("/dev/ksyms", O_RDONLY);
183		}
184		if (fd == -1)
185			return (-1);
186	}
187#else
188	if ((fd = open("/dev/ksyms", O_RDONLY)) == -1)
189		return (-1);
190#endif
191
192	(void) elf_version(EV_CURRENT);
193
194	elf = elf_begin(fd, ELF_C_READ, NULL);
195
196	for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
197		Shdr *shdr = elf_getshdr(scn);
198		if (shdr->sh_type == SHT_SYMTAB) {
199			symtab = (Sym *)elf_getdata(scn, NULL)->d_buf;
200			nsyms = shdr->sh_size / shdr->sh_entsize;
201			strindex = shdr->sh_link;
202		}
203	}
204
205	for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
206		if (cnt == strindex)
207			strtab = (char *)elf_getdata(scn, NULL)->d_buf;
208	}
209
210	lastsym = symtab + nsyms;
211	nsyms = 0;
212	for (symp = symtab; symp < lastsym; symp++)
213		if ((uint_t)ELF32_ST_TYPE(symp->st_info) <= STT_FUNC &&
214		    symp->st_size != 0)
215			add_symbol(symp->st_name + strtab,
216			    (uintptr_t)symp->st_value, (size_t)symp->st_size);
217
218	fake_up_certain_popular_kernel_symbols();
219	(void) sprintf(maxsymname, "0x%lx", ULONG_MAX);
220	add_symbol(maxsymname, ULONG_MAX, 1);
221
222	qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
223
224	/*
225	 * Destroy all duplicate symbols, then sort it again.
226	 */
227	for (i = 0; i < nsyms - 1; i++)
228		if (symbol_table[i].addr == symbol_table[i + 1].addr)
229			symbol_table[i].addr = 0;
230
231	qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
232
233	while (symbol_table[1].addr == 0) {
234		symbol_table++;
235		nsyms--;
236	}
237	symbol_table[0].name = "(usermode)";
238	symbol_table[0].addr = 0;
239	symbol_table[0].size = 1;
240
241	close(fd);
242	return (0);
243}
244
245char *
246addr_to_sym(uintptr_t addr, uintptr_t *offset, size_t *sizep)
247{
248	int lo = 0;
249	int hi = nsyms - 1;
250	int mid;
251	syment_t *sep;
252
253	while (hi - lo > 1) {
254		mid = (lo + hi) / 2;
255		if (addr >= symbol_table[mid].addr) {
256			lo = mid;
257		} else {
258			hi = mid;
259		}
260	}
261	sep = &symbol_table[lo];
262	*offset = addr - sep->addr;
263	*sizep = sep->size;
264	return (sep->name);
265}
266
267uintptr_t
268sym_to_addr(char *name)
269{
270	int i;
271	syment_t *sep = symbol_table;
272
273	for (i = 0; i < nsyms; i++) {
274		if (strcmp(name, sep->name) == 0)
275			return (sep->addr);
276		sep++;
277	}
278	return (0);
279}
280
281size_t
282sym_size(char *name)
283{
284	int i;
285	syment_t *sep = symbol_table;
286
287	for (i = 0; i < nsyms; i++) {
288		if (strcmp(name, sep->name) == 0)
289			return (sep->size);
290		sep++;
291	}
292	return (0);
293}
294