sym.c revision 257213 
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#if defined(sun)
46#include <sys/machelf.h>
47
48#include <kstat.h>
49#else
50/* FreeBSD */
51#include <sys/elf.h>
52#include <sys/ksyms.h>
53#endif
54#include <sys/cpuvar.h>
55
56typedef struct syment {
57	uintptr_t	addr;
58	char		*name;
59	size_t		size;
60} syment_t;
61
62static syment_t *symbol_table;
63static int nsyms, maxsyms;
64static char maxsymname[64];
65
66#if defined(sun)
67#ifdef _ELF64
68#define	elf_getshdr elf64_getshdr
69#else
70#define	elf_getshdr elf32_getshdr
71#endif
72#endif
73
74static void
75add_symbol(char *name, uintptr_t addr, size_t size)
76{
77	syment_t *sep;
78
79	if (nsyms >= maxsyms) {
80		maxsyms += 10000;
81		symbol_table = realloc(symbol_table, maxsyms * sizeof (*sep));
82		if (symbol_table == NULL) {
83			(void) fprintf(stderr, "can't allocate symbol table\n");
84			exit(3);
85		}
86	}
87	sep = &symbol_table[nsyms++];
88
89	sep->name = name;
90	sep->addr = addr;
91	sep->size = size;
92}
93
94static void
95remove_symbol(uintptr_t addr)
96{
97	int i;
98	syment_t *sep = symbol_table;
99
100	for (i = 0; i < nsyms; i++, sep++)
101		if (sep->addr == addr)
102			sep->addr = 0;
103}
104
105#if defined(sun)
106static void
107fake_up_certain_popular_kernel_symbols(void)
108{
109	kstat_ctl_t *kc;
110	kstat_t *ksp;
111	char *name;
112
113	if ((kc = kstat_open()) == NULL)
114		return;
115
116	for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
117		if (strcmp(ksp->ks_module, "cpu_info") == 0) {
118			if ((name = malloc(20)) == NULL)
119				break;
120			/*
121			 * For consistency, keep cpu[0] and toss cpu0
122			 * or any other such symbols.
123			 */
124			if (ksp->ks_instance == 0)
125				remove_symbol((uintptr_t)ksp->ks_private);
126			(void) sprintf(name, "cpu[%d]", ksp->ks_instance);
127			add_symbol(name, (uintptr_t)ksp->ks_private,
128			    sizeof (struct cpu));
129		}
130	}
131	(void) kstat_close(kc);
132}
133#else
134/* FreeBSD */
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 /* !defined(sun) */
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#if !defined(sun)
178	void		*ksyms;
179	size_t		sz;
180#endif
181
182#if defined(__FreeBSD__)
183	if ((fd = open("/dev/ksyms", O_RDONLY)) == -1) {
184		if (errno == ENOENT && modfind("ksyms") == -1) {
185			kldload("ksyms");
186			fd = open("/dev/ksyms", O_RDONLY);
187		}
188		if (fd == -1)
189			return (-1);
190	}
191#else
192	if ((fd = open("/dev/ksyms", O_RDONLY)) == -1)
193		return (-1);
194#endif
195
196#if defined(sun)
197	(void) elf_version(EV_CURRENT);
198
199	elf = elf_begin(fd, ELF_C_READ, NULL);
200#else
201	/* FreeBSD */
202	/*
203	 * XXX - libelf needs to be fixed so it will work with
204	 * non 'ordinary' files like /dev/ksyms.  The following
205	 * is a work around for now.
206	 */
207	if (elf_version(EV_CURRENT) == EV_NONE) {
208		close(fd);
209		return (-1);
210	}
211	if (ioctl(fd, KIOCGSIZE, &sz) < 0) {
212		close(fd);
213		return (-1);
214	}
215	if (ioctl(fd, KIOCGADDR, &ksyms) < 0) {
216		close(fd);
217		return (-1);
218	}
219	if ((elf = elf_memory(ksyms, sz)) == NULL) {
220		close(fd);
221		return (-1);
222	}
223#endif
224
225	for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
226		Shdr *shdr = elf_getshdr(scn);
227		if (shdr->sh_type == SHT_SYMTAB) {
228			symtab = (Sym *)elf_getdata(scn, NULL)->d_buf;
229			nsyms = shdr->sh_size / shdr->sh_entsize;
230			strindex = shdr->sh_link;
231		}
232	}
233
234	for (cnt = 1; (scn = elf_nextscn(elf, scn)) != NULL; cnt++) {
235		if (cnt == strindex)
236			strtab = (char *)elf_getdata(scn, NULL)->d_buf;
237	}
238
239	lastsym = symtab + nsyms;
240	nsyms = 0;
241	for (symp = symtab; symp < lastsym; symp++)
242		if ((uint_t)ELF32_ST_TYPE(symp->st_info) <= STT_FUNC &&
243		    symp->st_size != 0)
244			add_symbol(symp->st_name + strtab,
245			    (uintptr_t)symp->st_value, (size_t)symp->st_size);
246
247	fake_up_certain_popular_kernel_symbols();
248	(void) sprintf(maxsymname, "0x%lx", ULONG_MAX);
249	add_symbol(maxsymname, ULONG_MAX, 1);
250
251	qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
252
253	/*
254	 * Destroy all duplicate symbols, then sort it again.
255	 */
256	for (i = 0; i < nsyms - 1; i++)
257		if (symbol_table[i].addr == symbol_table[i + 1].addr)
258			symbol_table[i].addr = 0;
259
260	qsort(symbol_table, nsyms, sizeof (syment_t), symcmp);
261
262	while (symbol_table[1].addr == 0) {
263		symbol_table++;
264		nsyms--;
265	}
266	symbol_table[0].name = "(usermode)";
267	symbol_table[0].addr = 0;
268	symbol_table[0].size = 1;
269
270	close(fd);
271	return (0);
272}
273
274char *
275addr_to_sym(uintptr_t addr, uintptr_t *offset, size_t *sizep)
276{
277	int lo = 0;
278	int hi = nsyms - 1;
279	int mid;
280	syment_t *sep;
281
282	while (hi - lo > 1) {
283		mid = (lo + hi) / 2;
284		if (addr >= symbol_table[mid].addr) {
285			lo = mid;
286		} else {
287			hi = mid;
288		}
289	}
290	sep = &symbol_table[lo];
291	*offset = addr - sep->addr;
292	*sizep = sep->size;
293	return (sep->name);
294}
295
296uintptr_t
297sym_to_addr(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->addr);
305		sep++;
306	}
307	return (0);
308}
309
310size_t
311sym_size(char *name)
312{
313	int i;
314	syment_t *sep = symbol_table;
315
316	for (i = 0; i < nsyms; i++) {
317		if (strcmp(name, sep->name) == 0)
318			return (sep->size);
319		sep++;
320	}
321	return (0);
322}
323