1 | /* Copyright (C) 1999-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Contributed by Andreas Jaeger <aj@suse.de>, 1999 and |
4 | Jakub Jelinek <jakub@redhat.com>, 1999. |
5 | |
6 | This program is free software; you can redistribute it and/or modify |
7 | it under the terms of the GNU General Public License as published |
8 | by the Free Software Foundation; version 2 of the License, or |
9 | (at your option) any later version. |
10 | |
11 | This program is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | GNU General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU General Public License |
17 | along with this program; if not, see <http://www.gnu.org/licenses/>. */ |
18 | |
19 | /* The code in this file and in readelflib is a heavily simplified |
20 | version of the readelf program that's part of the current binutils |
21 | development version. Besides the simplification, it has also been |
22 | modified to read some other file formats. */ |
23 | |
24 | #include <a.out.h> |
25 | #include <elf.h> |
26 | #include <error.h> |
27 | #include <libintl.h> |
28 | #include <link.h> |
29 | #include <stdio.h> |
30 | #include <string.h> |
31 | #include <unistd.h> |
32 | #include <sys/mman.h> |
33 | #include <sys/param.h> |
34 | #include <sys/stat.h> |
35 | #include <gnu/lib-names.h> |
36 | |
37 | #include <ldconfig.h> |
38 | |
39 | #define Elf32_CLASS ELFCLASS32 |
40 | #define Elf64_CLASS ELFCLASS64 |
41 | |
42 | struct known_names |
43 | { |
44 | const char *soname; |
45 | int flag; |
46 | }; |
47 | |
48 | static struct known_names interpreters[] = |
49 | { |
50 | { "/lib/" LD_SO, FLAG_ELF_LIBC6 }, |
51 | #ifdef SYSDEP_KNOWN_INTERPRETER_NAMES |
52 | SYSDEP_KNOWN_INTERPRETER_NAMES |
53 | #endif |
54 | }; |
55 | |
56 | static struct known_names known_libs[] = |
57 | { |
58 | { LIBC_SO, FLAG_ELF_LIBC6 }, |
59 | { LIBM_SO, FLAG_ELF_LIBC6 }, |
60 | #ifdef SYSDEP_KNOWN_LIBRARY_NAMES |
61 | SYSDEP_KNOWN_LIBRARY_NAMES |
62 | #endif |
63 | }; |
64 | |
65 | |
66 | /* Check if string corresponds to a GDB Python file. */ |
67 | static bool |
68 | is_gdb_python_file (const char *name) |
69 | { |
70 | size_t len = strlen (name); |
71 | return len > 7 && strcmp (name + len - 7, "-gdb.py" ) == 0; |
72 | } |
73 | |
74 | /* Returns 0 if everything is ok, != 0 in case of error. */ |
75 | int |
76 | process_file (const char *real_file_name, const char *file_name, |
77 | const char *lib, int *flag, unsigned int *osversion, |
78 | char **soname, int is_link, struct stat64 *stat_buf) |
79 | { |
80 | FILE *file; |
81 | struct stat64 statbuf; |
82 | void *file_contents; |
83 | int ret; |
84 | ElfW(Ehdr) *; |
85 | struct exec *; |
86 | |
87 | ret = 0; |
88 | *flag = FLAG_ANY; |
89 | *soname = NULL; |
90 | |
91 | file = fopen (real_file_name, "rb" ); |
92 | if (file == NULL) |
93 | { |
94 | /* No error for stale symlink. */ |
95 | if (is_link && strstr (file_name, ".so" ) != NULL) |
96 | return 1; |
97 | error (0, 0, _("Input file %s not found.\n" ), file_name); |
98 | return 1; |
99 | } |
100 | |
101 | if (fstat64 (fileno (file), &statbuf) < 0) |
102 | { |
103 | error (0, 0, _("Cannot fstat file %s.\n" ), file_name); |
104 | fclose (file); |
105 | return 1; |
106 | } |
107 | |
108 | /* Check that the file is large enough so that we can access the |
109 | information. We're only checking the size of the headers here. */ |
110 | if ((size_t) statbuf.st_size < sizeof (struct exec) |
111 | || (size_t) statbuf.st_size < sizeof (ElfW(Ehdr))) |
112 | { |
113 | if (statbuf.st_size == 0) |
114 | error (0, 0, _("File %s is empty, not checked." ), file_name); |
115 | else |
116 | { |
117 | char buf[SELFMAG]; |
118 | size_t n = MIN (statbuf.st_size, SELFMAG); |
119 | if (fread (buf, n, 1, file) == 1 && memcmp (buf, ELFMAG, n) == 0) |
120 | error (0, 0, _("File %s is too small, not checked." ), file_name); |
121 | } |
122 | fclose (file); |
123 | return 1; |
124 | } |
125 | |
126 | file_contents = mmap (0, statbuf.st_size, PROT_READ, MAP_SHARED, |
127 | fileno (file), 0); |
128 | if (file_contents == MAP_FAILED) |
129 | { |
130 | error (0, 0, _("Cannot mmap file %s.\n" ), file_name); |
131 | fclose (file); |
132 | return 1; |
133 | } |
134 | |
135 | /* First check if this is an aout file. */ |
136 | aout_header = (struct exec *) file_contents; |
137 | if (N_MAGIC (*aout_header) == ZMAGIC |
138 | #ifdef QMAGIC /* Linuxism. */ |
139 | || N_MAGIC (*aout_header) == QMAGIC |
140 | #endif |
141 | ) |
142 | { |
143 | /* Aout files don't have a soname, just return the name |
144 | including the major number. */ |
145 | char *copy, *major, *dot; |
146 | copy = xstrdup (lib); |
147 | major = strstr (copy, ".so." ); |
148 | if (major) |
149 | { |
150 | dot = strstr (major + 4, "." ); |
151 | if (dot) |
152 | *dot = '\0'; |
153 | } |
154 | *soname = copy; |
155 | *flag = FLAG_LIBC4; |
156 | goto done; |
157 | } |
158 | |
159 | elf_header = (ElfW(Ehdr) *) file_contents; |
160 | if (memcmp (elf_header->e_ident, ELFMAG, SELFMAG) != 0) |
161 | { |
162 | /* The file is neither ELF nor aout. Check if it's a linker |
163 | script, like libc.so - otherwise complain. Only search the |
164 | beginning of the file. */ |
165 | size_t len = MIN (statbuf.st_size, 512); |
166 | if (memmem (file_contents, len, "GROUP" , 5) == NULL |
167 | && memmem (file_contents, len, "GNU ld script" , 13) == NULL |
168 | && !is_gdb_python_file (file_name)) |
169 | error (0, 0, _("%s is not an ELF file - it has the wrong magic bytes at the start.\n" ), |
170 | file_name); |
171 | ret = 1; |
172 | } |
173 | /* Libraries have to be shared object files. */ |
174 | else if (elf_header->e_type != ET_DYN) |
175 | ret = 1; |
176 | else if (process_elf_file (file_name, lib, flag, osversion, soname, |
177 | file_contents, statbuf.st_size)) |
178 | ret = 1; |
179 | |
180 | done: |
181 | /* Clean up allocated memory and resources. */ |
182 | munmap (file_contents, statbuf.st_size); |
183 | fclose (file); |
184 | |
185 | *stat_buf = statbuf; |
186 | return ret; |
187 | } |
188 | |
189 | /* Returns made up soname if lib doesn't have explicit DT_SONAME. */ |
190 | |
191 | char * |
192 | implicit_soname (const char *lib, int flag) |
193 | { |
194 | char *soname = xstrdup (lib); |
195 | |
196 | if ((flag & FLAG_TYPE_MASK) != FLAG_LIBC4) |
197 | return soname; |
198 | |
199 | /* Aout files don't have a soname, just return the name |
200 | including the major number. */ |
201 | char *major = strstr (soname, ".so." ); |
202 | if (major) |
203 | { |
204 | char *dot = strstr (major + 4, "." ); |
205 | if (dot) |
206 | *dot = '\0'; |
207 | } |
208 | return soname; |
209 | } |
210 | |
211 | /* Get architecture specific version of process_elf_file. */ |
212 | #include <readelflib.c> |
213 | |