sym.c revision 297077 
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/ksyms.h>
52#endif
53#include <sys/cpuvar.h>
54
55typedef struct syment {
56	uintptr_t	addr;
57	char		*name;
58	size_t		size;
59} syment_t;
60
61static syment_t *symbol_table;
62static int nsyms, maxsyms;
63static char maxsymname[64];
64
65#ifdef illumos
66#ifdef _ELF64
67#define	elf_getshdr elf64_getshdr
68#else
69#define	elf_getshdr elf32_getshdr
70#endif
71#endif
72
73static void
74add_symbol(char *name, uintptr_t addr, size_t size)
75{
76	syment_t *sep;
77
78	if (nsyms >= maxsyms) {
79		maxsyms += 10000;
80		symbol_table = realloc(symbol_table, maxsyms * sizeof (*sep));
81		if (symbol_table == NULL) {
82			(void) fprintf(stderr, "can't allocate symbol table\n");
83			exit(3);
84		}
85	}
86	sep = &symbol_table[nsyms++];
87
88	sep->name = name;
89	sep->addr = addr;
90	sep->size = size;
91}
92
93static void
94remove_symbol(uintptr_t addr)
95{
96	int i;
97	syment_t *sep = symbol_table;
98
99	for (i = 0; i < nsyms; i++, sep++)
100		if (sep->addr == addr)
101			sep->addr = 0;
102}
103
104#ifdef illumos
105static void
106fake_up_certain_popular_kernel_symbols(void)
107{
108	kstat_ctl_t *kc;
109	kstat_t *ksp;
110	char *name;
111
112	if ((kc = kstat_open()) == NULL)
113		return;
114
115	for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
116		if (strcmp(ksp->ks_module, "cpu_info") == 0) {
117			if ((name = malloc(20)) == NULL)
118				break;
119			/*
120			 * For consistency, keep cpu[0] and toss cpu0
121			 * or any other such symbols.
122			 */
123			if (ksp->ks_instance == 0)
124				remove_symbol((uintptr_t)ksp->ks_private);
125			(void) sprintf(name, "cpu[%d]", ksp->ks_instance);
126			add_symbol(name, (uintptr_t)ksp->ks_private,
127			    sizeof (struct cpu));
128		}
129	}
130	(void) kstat_close(kc);
131}
132#else /* !illumos */
133static void
134fake_up_certain_popular_kernel_symbols(void)
135{
136	char *name;
137	uintptr_t addr;
138	int i;
139
140	/* Good for up to 256 CPUs */
141	for(i=0; i < 256;  i++) {
142		if ((name = malloc(20)) == NULL)
143			break;
144		(void) sprintf(name, "cpu[%d]", i);
145		addr = 0x01000000 + (i << 16);
146		add_symbol(name, addr, sizeof (uintptr_t));
147	}
148}
149#endif /* illumos */
150
151static int
152symcmp(const void *p1, const void *p2)
153{
154	uintptr_t a1 = ((syment_t *)p1)->addr;
155	uintptr_t a2 = ((syment_t *)p2)->addr;
156
157	if (a1 < a2)
158		return (-1);
159	if (a1 > a2)
160		return (1);
161	return (0);
162}
163
164int
165symtab_init(void)
166{
167	Elf		*elf;
168	Elf_Scn		*scn = NULL;
169	Sym		*symtab, *symp, *lastsym;
170	char		*strtab;
171	uint_t		cnt;
172	int		fd;
173	int		i;
174	int		strindex = -1;
175#ifndef illumos
176	void		*ksyms;
177	size_t		sz;
178#endif
179
180	if ((fd = open("/dev/ksyms", O_RDONLY)) == -1)
181		return (-1);
182
183#ifdef illumos
184	(void) elf_version(EV_CURRENT);
185
186	elf = elf_begin(fd, ELF_C_READ, NULL);
187#else
188	/*
189	 * XXX - libelf needs to be fixed so it will work with
190	 * non 'ordinary' files like /dev/ksyms.  The following
191	 * is a work around for now.
192	 */
193	if (elf_version(EV_CURRENT) == EV_NONE) {
194		close(fd);
195		return (-1);
196	}
197	if (ioctl(fd, KIOCGSIZE, &sz) < 0) {
198		close(fd);
199		return (-1);
200	}
201	if (ioctl(fd, KIOCGADDR, &ksyms) < 0) {
202		close(fd);
203		return (-1);
204	}
205	if ((elf = elf_memory(ksyms, sz)) == NULL) {
206		close(fd);
207		return (-1);
208	}
209#endif
210
211	for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
212		Shdr *shdr = elf_getshdr(scn);
213		if (shdr->sh_type == SHT_SYMTAB) {
214			symtab = (Sym *)elf_getdata(scn, NULL)->d_buf;
215			nsyms = shdr->sh_size / shdr->sh_entsize;
216			strindex = shdr->sh_link;
217		}
218	}
219
220	for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
221		if (cnt == strindex)
222			strtab = (char *)elf_getdata(scn, NULL)->d_buf;
223	}
224
225	lastsym = symtab + nsyms;
226	nsyms = 0;
227	for (symp = symtab; symp < lastsym; symp++)
228		if ((uint_t)ELF32_ST_TYPE(symp->st_info) <= STT_FUNC &&
229		    symp->st_size != 0)
230			add_symbol(symp->st_name + strtab,
231			    (uintptr_t)symp->st_value, (size_t)symp->st_size);
232
233	fake_up_certain_popular_kernel_symbols();
234	(void) sprintf(maxsymname, "0x%lx", ULONG_MAX);
235	add_symbol(maxsymname, ULONG_MAX, 1);
236
237	qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
238
239	/*
240	 * Destroy all duplicate symbols, then sort it again.
241	 */
242	for (i = 0; i < nsyms - 1; i++)
243		if (symbol_table[i].addr == symbol_table[i + 1].addr)
244			symbol_table[i].addr = 0;
245
246	qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
247
248	while (symbol_table[1].addr == 0) {
249		symbol_table++;
250		nsyms--;
251	}
252	symbol_table[0].name = "(usermode)";
253	symbol_table[0].addr = 0;
254	symbol_table[0].size = 1;
255
256	close(fd);
257	return (0);
258}
259
260char *
261addr_to_sym(uintptr_t addr, uintptr_t *offset, size_t *sizep)
262{
263	int lo = 0;
264	int hi = nsyms - 1;
265	int mid;
266	syment_t *sep;
267
268	while (hi - lo > 1) {
269		mid = (lo + hi) / 2;
270		if (addr >= symbol_table[mid].addr) {
271			lo = mid;
272		} else {
273			hi = mid;
274		}
275	}
276	sep = &symbol_table[lo];
277	*offset = addr - sep->addr;
278	*sizep = sep->size;
279	return (sep->name);
280}
281
282uintptr_t
283sym_to_addr(char *name)
284{
285	int i;
286	syment_t *sep = symbol_table;
287
288	for (i = 0; i < nsyms; i++) {
289		if (strcmp(name, sep->name) == 0)
290			return (sep->addr);
291		sep++;
292	}
293	return (0);
294}
295
296size_t
297sym_size(char *name)
298{
299	int i;
300	syment_t *sep = symbol_table;
301
302	for (i = 0; i < nsyms; i++) {
303		if (strcmp(name, sep->name) == 0)
304			return (sep->size);
305		sep++;
306	}
307	return (0);
308}
309