1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if 0
33/* From: */
34#endif
35
36#include <sys/types.h>
37#include <sys/mman.h>
38#include <sys/stat.h>
39#include <machine/elf.h>
40
41#include <err.h>
42#include <fcntl.h>
43#include <string.h>
44#include <unistd.h>
45
46#include "gprof.h"
47
48static bool wantsym(const Elf_Sym *, const char *);
49
50/* Things which get -E excluded by default. */
51static char	*excludes[] = { ".mcount", "_mcleanup", NULL };
52
53int
54elf_getnfile(const char *filename, char ***defaultEs)
55{
56    int fd;
57    Elf_Ehdr h;
58    struct stat s;
59    void *mapbase;
60    const char *base;
61    const Elf_Shdr *shdrs;
62    const Elf_Shdr *sh_symtab;
63    const Elf_Shdr *sh_strtab;
64    const char *strtab;
65    const Elf_Sym *symtab;
66    int symtabct;
67    int i;
68
69    if ((fd = open(filename, O_RDONLY)) == -1)
70	err(1, "%s", filename);
71    if (read(fd, &h, sizeof h) != sizeof h || !IS_ELF(h)) {
72	close(fd);
73	return -1;
74    }
75    if (fstat(fd, &s) == -1)
76	err(1, "cannot fstat %s", filename);
77    if ((mapbase = mmap(0, s.st_size, PROT_READ, MAP_SHARED, fd, 0)) ==
78      MAP_FAILED)
79	err(1, "cannot mmap %s", filename);
80    close(fd);
81
82    base = (const char *)mapbase;
83    shdrs = (const Elf_Shdr *)(base + h.e_shoff);
84
85    /* Find the symbol table and associated string table section. */
86    for (i = 1;  i < h.e_shnum;  i++)
87	if (shdrs[i].sh_type == SHT_SYMTAB)
88	    break;
89    if (i == h.e_shnum)
90	errx(1, "%s has no symbol table", filename);
91    sh_symtab = &shdrs[i];
92    sh_strtab = &shdrs[sh_symtab->sh_link];
93
94    symtab = (const Elf_Sym *)(base + sh_symtab->sh_offset);
95    symtabct = sh_symtab->sh_size / sh_symtab->sh_entsize;
96    strtab = (const char *)(base + sh_strtab->sh_offset);
97
98    /* Count the symbols that we're interested in. */
99    nname = 0;
100    for (i = 1;  i < symtabct;  i++)
101	if (wantsym(&symtab[i], strtab))
102	    nname++;
103
104    /* Allocate memory for them, plus a terminating entry. */
105    if ((nl = (nltype *)calloc(nname + 1, sizeof(nltype))) == NULL)
106	errx(1, "insufficient memory for symbol table");
107
108    /* Read them in. */
109    npe = nl;
110    for (i = 1;  i < symtabct;  i++) {
111	const Elf_Sym *sym = &symtab[i];
112
113	if (wantsym(sym, strtab)) {
114	    npe->value = sym->st_value;
115	    npe->name = strtab + sym->st_name;
116	    npe++;
117	}
118    }
119    npe->value = -1;
120
121    *defaultEs = excludes;
122    return 0;
123}
124
125static bool
126wantsym(const Elf_Sym *sym, const char *strtab)
127{
128    int type;
129    int bind;
130
131    type = ELF_ST_TYPE(sym->st_info);
132    bind = ELF_ST_BIND(sym->st_info);
133
134    if (type != STT_FUNC ||
135      (aflag && bind == STB_LOCAL) ||
136      (uflag && strchr(strtab + sym->st_name, '.') != NULL))
137	return 0;
138
139    return 1;
140}
141