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 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 #include "fenv_synonyms.h"
31 #include <elf.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <unistd.h>
35 #include <fcntl.h>
36 #include <procfs.h>
37 #include <string.h>
38 #include <sys/stat.h>
39
40 #if defined(__sparcv9) || defined(__amd64)
41
42 #define Elf_Ehdr Elf64_Ehdr
43 #define Elf_Phdr Elf64_Phdr
44 #define Elf_Shdr Elf64_Shdr
45 #define Elf_Sym Elf64_Sym
46 #define ELF_ST_BIND ELF64_ST_BIND
47 #define ELF_ST_TYPE ELF64_ST_TYPE
48
49 #else
50
51 #define Elf_Ehdr Elf32_Ehdr
52 #define Elf_Phdr Elf32_Phdr
53 #define Elf_Shdr Elf32_Shdr
54 #define Elf_Sym Elf32_Sym
55 #define ELF_ST_BIND ELF32_ST_BIND
56 #define ELF_ST_TYPE ELF32_ST_TYPE
57
58 #endif /* __sparcv9 */
59
60 /* semi-permanent data established by __fex_sym_init */
61 static prmap_t *pm = NULL; /* prmap_t array */
62 static int npm = 0; /* number of entries in pm */
63
64 /* transient data modified by __fex_sym */
65 static prmap_t *lpm = NULL; /* prmap_t found in last call */
66 static Elf_Phdr *ph = NULL; /* program header array */
67 static int phsize = 0; /* size of ph */
68 static int nph; /* number of entries in ph */
69 static char *stbuf = NULL; /* symbol and string table buffer */
70 static int stbufsize = 0; /* size of stbuf */
71 static int stoffset; /* offset of string table in stbuf */
72 static int nsyms; /* number of symbols in stbuf */
73
74 /* get a current prmap_t list (must call this before each stack trace) */
75 void
76 __fex_sym_init()
77 {
78 struct stat statbuf;
79 long n;
80 int i;
81
82 /* clear out the previous prmap_t list */
83 if (pm != NULL)
84 free(pm);
85 pm = lpm = NULL;
86 npm = 0;
87
88 /* get the current prmap_t list */
89 if (stat("/proc/self/map", &statbuf) < 0 || statbuf.st_size <= 0 ||
90 (pm = (prmap_t*)malloc(statbuf.st_size)) == NULL)
91 return;
92 if ((i = open("/proc/self/map", O_RDONLY)) < 0)
93 {
94 free(pm);
95 pm = NULL;
96 return;
97 }
98 n = read(i, pm, statbuf.st_size);
99 close(i);
100 if (n != statbuf.st_size)
101 {
102 free(pm);
103 pm = NULL;
104 }
105 else
106 npm = (int) (n / sizeof(prmap_t));
107 }
108
109 /* read ELF program headers and symbols; return -1 on error, 0 otherwise */
110 static int
111 __fex_read_syms(int fd)
112 {
113 Elf_Ehdr h;
114 Elf_Shdr *sh;
115 int i, size;
116
117 /* read the ELF header */
118 if (read(fd, &h, sizeof(h)) != sizeof(h))
119 return -1;
120 if (h.e_ident[EI_MAG0] != ELFMAG0 ||
121 h.e_ident[EI_MAG1] != ELFMAG1 ||
122 h.e_ident[EI_MAG2] != ELFMAG2 ||
123 h.e_ident[EI_MAG3] != ELFMAG3 ||
124 h.e_phentsize != sizeof(Elf_Phdr) ||
125 h.e_shentsize != sizeof(Elf_Shdr))
126 return -1;
127
128 /* get space for the program headers */
129 size = h.e_phnum * h.e_phentsize;
130 if (size > phsize)
131 {
132 if (ph)
133 free(ph);
134 phsize = nph = 0;
135 if ((ph = (Elf_Phdr*)malloc(size)) == NULL)
136 return -1;
137 phsize = size;
138 }
139
140 /* read the program headers */
141 if (lseek(fd, h.e_phoff, SEEK_SET) != h.e_phoff ||
142 read(fd, ph, size) != (ssize_t)size)
143 {
144 nph = 0;
145 return -1;
146 }
147 nph = h.e_phnum;
148
149 /* read the section headers */
150 size = h.e_shnum * h.e_shentsize;
151 if ((sh = (Elf_Shdr*)malloc(size)) == NULL)
152 return -1;
153 if (lseek(fd, h.e_shoff, SEEK_SET) != h.e_shoff ||
154 read(fd, sh, size) != (ssize_t)size)
155 {
156 free(sh);
157 return -1;
158 }
159
160 /* find the symtab section header */
161 for (i = 0; i < h.e_shnum; i++)
162 {
163 if (sh[i].sh_type == SHT_SYMTAB)
164 break; /* assume there is only one */
165 }
166 if (i == h.e_shnum || sh[i].sh_size == 0 ||
167 sh[i].sh_entsize != sizeof(Elf_Sym) ||
168 sh[i].sh_link < 1 || sh[i].sh_link >= h.e_shnum ||
169 sh[sh[i].sh_link].sh_type != SHT_STRTAB ||
170 sh[sh[i].sh_link].sh_size == 0)
171 {
172 free(sh);
173 return -1;
174 }
175
176 /* get space for the symbol and string tables */
177 size = (int) (sh[i].sh_size + sh[sh[i].sh_link].sh_size);
178 if (size > stbufsize)
179 {
180 if (stbuf)
181 free(stbuf);
182 stbufsize = nsyms = 0;
183 if ((stbuf = (char*)malloc(size)) == NULL)
184 {
185 free(sh);
186 return -1;
187 }
188 stbufsize = size;
189 }
190
191 /* read the symbol and string tables */
192 if (lseek(fd, sh[i].sh_offset, SEEK_SET) != sh[i].sh_offset ||
193 read(fd, stbuf, sh[i].sh_size) != sh[i].sh_size ||
194 lseek(fd, sh[sh[i].sh_link].sh_offset, SEEK_SET) !=
195 sh[sh[i].sh_link].sh_offset ||
196 read(fd, stbuf + sh[i].sh_size, sh[sh[i].sh_link].sh_size) !=
197 sh[sh[i].sh_link].sh_size)
198 {
199 free(sh);
200 return (-1);
201 }
202 nsyms = (int) (sh[i].sh_size / sh[i].sh_entsize);
203 stoffset = (int) sh[i].sh_size;
204
205 free(sh);
206 return (0);
207 }
208
209 /* find the symbol corresponding to the given text address;
210 return NULL on error, symbol address otherwise */
211 char *
212 __fex_sym(char *a, char **name)
213 {
214 Elf_Sym *s;
215 unsigned long fo, va, value;
216 int fd, i, j, nm;
217 char fname[PRMAPSZ+20];
218
219 /* see if the last prmap_t found contains the indicated address */
220 if (lpm)
221 {
222 if (a >= (char*)lpm->pr_vaddr && a < (char*)lpm->pr_vaddr +
223 lpm->pr_size)
224 goto cont;
225 }
226
227 /* look for a prmap_t that contains the indicated address */
228 for (i = 0; i < npm; i++)
229 {
230 if (a >= (char*)pm[i].pr_vaddr && a < (char*)pm[i].pr_vaddr +
231 pm[i].pr_size)
232 break;
233 }
234 if (i == npm)
235 return NULL;
236
237 /* get an open file descriptor for the mapped object */
238 if (pm[i].pr_mapname[0] == '\0')
239 return NULL;
240 strcpy(fname, "/proc/self/object/");
241 strncat(fname, pm[i].pr_mapname, PRMAPSZ);
242 fd = open(fname, O_RDONLY);
243 if (fd < 0)
244 return NULL;
245
246 /* read the program headers and symbols */
247 lpm = NULL;
248 j = __fex_read_syms(fd);
249 close(fd);
250 if (j < 0)
251 return NULL;
252 lpm = &pm[i];
253
254 cont:
255 /* compute the file offset corresponding to the mapped address */
256 fo = (a - (char*)lpm->pr_vaddr) + lpm->pr_offset;
257
258 /* find the program header containing the file offset */
259 for (i = 0; i < nph; i++)
260 {
261 if (ph[i].p_type == PT_LOAD && fo >= ph[i].p_offset &&
262 fo < ph[i].p_offset + ph[i].p_filesz)
263 break;
264 }
265 if (i == nph)
266 return NULL;
267
268 /* compute the virtual address corresponding to the file offset */
269 va = (fo - ph[i].p_offset) + ph[i].p_vaddr;
270
271 /* find the symbol in this segment with the highest value
272 less than or equal to the virtual address */
273 s = (Elf_Sym*)stbuf;
274 value = nm = 0;
275 for (j = 0; j < nsyms; j++)
276 {
277 if (s[j].st_name == 0 || s[j].st_shndx == SHN_UNDEF ||
278 (ELF_ST_BIND(s[j].st_info) != STB_LOCAL &&
279 ELF_ST_BIND(s[j].st_info) != STB_GLOBAL &&
280 ELF_ST_BIND(s[j].st_info) != STB_WEAK) ||
281 (ELF_ST_TYPE(s[j].st_info) != STT_NOTYPE &&
282 ELF_ST_TYPE(s[j].st_info) != STT_OBJECT &&
283 ELF_ST_TYPE(s[j].st_info) != STT_FUNC))
284 {
285 continue;
286 }
287
288 if (s[j].st_value < ph[i].p_vaddr || s[j].st_value >= ph[i].p_vaddr
289 + ph[i].p_memsz)
290 {
291 continue;
292 }
293
294 if (s[j].st_value < value || s[j].st_value > va)
295 continue;
296
297 value = s[j].st_value;
298 nm = s[j].st_name;
299 }
300 if (nm == 0)
301 return NULL;
302
303 /* pass back the name and return the mapped address of the symbol */
304 *name = stbuf + stoffset + nm;
305 fo = (value - ph[i].p_vaddr) + ph[i].p_offset;
306 return (char*)lpm->pr_vaddr + (fo - lpm->pr_offset);
307 }