1 /*-
2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/types.h>
31 #include <sys/mman.h>
32 #include <sys/stat.h>
33
34 #include <elf.h>
35 #include <err.h>
36 #include <fcntl.h>
37 #include <string.h>
38 #include <unistd.h>
39
40 #include "gprof.h"
41
42 static bool wantsym(const Elf_Sym *, const char *);
43
44 /* Things which get -E excluded by default. */
45 static char *excludes[] = { ".mcount", "_mcleanup", NULL };
46
47 int
getnfile(const char * filename,char *** defaultEs)48 getnfile(const char *filename, char ***defaultEs)
49 {
50 int fd;
51 Elf_Ehdr h;
52 struct stat s;
53 void *mapbase;
54 const char *base;
55 const Elf_Shdr *shdrs;
56 const Elf_Shdr *sh_symtab;
57 const Elf_Shdr *sh_strtab;
58 const char *strtab;
59 const Elf_Sym *symtab;
60 int symtabct;
61 int i;
62
63 if ((fd = open(filename, O_RDONLY)) == -1)
64 err(1, "%s", filename);
65 if (read(fd, &h, sizeof h) != sizeof h || !IS_ELF(h)) {
66 close(fd);
67 return -1;
68 }
69 if (fstat(fd, &s) == -1)
70 err(1, "Cannot fstat %s", filename);
71 if ((mapbase = mmap(0, s.st_size, PROT_READ, MAP_SHARED, fd, 0)) ==
72 MAP_FAILED)
73 err(1, "Cannot mmap %s", filename);
74 close(fd);
75
76 base = (const char *)mapbase;
77 shdrs = (const Elf_Shdr *)(base + h.e_shoff);
78
79 /* Find the symbol table and associated string table section. */
80 for (i = 1; i < h.e_shnum; i++)
81 if (shdrs[i].sh_type == SHT_SYMTAB)
82 break;
83 if (i == h.e_shnum)
84 errx(1, "%s has no symbol table", filename);
85 sh_symtab = &shdrs[i];
86 sh_strtab = &shdrs[sh_symtab->sh_link];
87
88 symtab = (const Elf_Sym *)(base + sh_symtab->sh_offset);
89 symtabct = sh_symtab->sh_size / sh_symtab->sh_entsize;
90 strtab = (const char *)(base + sh_strtab->sh_offset);
91
92 /* Count the symbols that we're interested in. */
93 nname = 0;
94 for (i = 1; i < symtabct; i++)
95 if (wantsym(&symtab[i], strtab))
96 nname++;
97
98 #ifdef DEBUG
99 if (debug & ELFDEBUG) {
100 printf("[getnfile] symtab at %p, strtab at %p\n", symtab, strtab);
101 printf("[getnfile] %d of %d symbols wanted\n", nname, symtabct);
102 }
103 #endif
104
105 /* Allocate memory for them, plus a terminating entry. */
106 if ((nl = calloc(nname + 1, sizeof(nltype))) == NULL)
107 errx(1, "Insufficient memory for symbol table");
108
109 /* Read them in. */
110 npe = nl;
111 for (i = 1; i < symtabct; i++) {
112 const Elf_Sym *sym = &symtab[i];
113
114 if (wantsym(sym, strtab)) {
115 npe->value = sym->st_value;
116 npe->name = strtab + sym->st_name;
117 #ifdef DEBUG
118 if (debug & ELFDEBUG)
119 printf("[getnfile] symbol %d: %s -> %lx\n", i,
120 npe->name ? npe->name : "(none)", npe->value);
121 #endif
122 npe++;
123 }
124 }
125 npe->value = -1;
126
127 *defaultEs = excludes;
128 return 0;
129 }
130
131 static bool
wantsym(const Elf_Sym * sym,const char * strtab)132 wantsym(const Elf_Sym *sym, const char *strtab)
133 {
134 int type;
135 int bind;
136
137 type = ELF_ST_TYPE(sym->st_info);
138 bind = ELF_ST_BIND(sym->st_info);
139
140 if (type != STT_FUNC || (aflag && bind == STB_LOCAL))
141 #if 0
142 ||
143 (uflag && strchr(strtab + sym->st_name, '.') != NULL))
144 #endif
145 return 0;
146
147 #ifdef __arm__
148 /* ignore what gas calls "mapping symbols" */
149 {
150 const char *c = strtab + sym->st_name;
151 if (c[0] == '$')
152 return 0;
153 }
154 #endif
155
156 return 1;
157 }
158