1 /* Copyright (C) 2015 Red Hat, Inc.
2 This file is part of elfutils.
3
4 This file is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 elfutils is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17 #ifdef HAVE_CONFIG_H
18 # include <config.h>
19 #endif
20
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <fcntl.h>
24 #include <inttypes.h>
25 #include <libelf.h>
26 #include <gelf.h>
27 #include <stdbool.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32
33
34 int
main(int argc,char * argv[])35 main (int argc, char *argv[])
36 {
37 int result = 0;
38 int cnt;
39
40 if (argc < 3
41 || (strcmp (argv[1], "elf") != 0
42 && strcmp (argv[1], "gnu") != 0))
43 {
44 printf ("Usage: (elf|gnu) files...\n");
45 return -1;
46 }
47
48 int gnu;
49 if (strcmp (argv[1], "gnu") == 0)
50 gnu = 1;
51 else
52 gnu = 0;
53
54 elf_version (EV_CURRENT);
55
56 for (cnt = 2; cnt < argc; ++cnt)
57 {
58 int fd = open (argv[cnt], O_RDONLY);
59
60 Elf *elf = elf_begin (fd, ELF_C_READ, NULL);
61 if (elf == NULL)
62 {
63 printf ("%s not usable %s\n", argv[cnt], elf_errmsg (-1));
64 result = 1;
65 close (fd);
66 continue;
67 }
68
69 /* To get the section names. */
70 size_t strndx;
71 elf_getshdrstrndx (elf, &strndx);
72
73 Elf_Scn *scn = NULL;
74 while ((scn = elf_nextscn (elf, scn)) != NULL)
75 {
76 size_t idx = elf_ndxscn (scn);
77 GElf_Shdr mem;
78 GElf_Shdr *shdr = gelf_getshdr (scn, &mem);
79 const char *name = elf_strptr (elf, strndx, shdr->sh_name);
80 if (shdr->sh_type == SHT_NOBITS
81 || (shdr->sh_flags & SHF_ALLOC) != 0)
82 {
83 printf ("Cannot compress %zd %s\n", idx, name);
84 }
85 else if ((shdr->sh_flags & SHF_COMPRESSED) != 0
86 || strncmp (name, ".zdebug", strlen (".zdebug")) == 0)
87 {
88 printf ("Already compressed %zd %s\n", idx, name);
89 }
90 else
91 {
92 size_t orig_size = shdr->sh_size;
93 printf ("Lets compress %zd %s, size: %" PRId64 "\n",
94 idx, name, shdr->sh_size);
95 Elf_Data *d = elf_getdata (scn, NULL);
96 if (d == NULL)
97 {
98 printf ("Couldn't get orig data for section %zd\n", idx);
99 return -1;
100 }
101 /* Make a copy so we can compare after
102 compression/decompression. */
103 if (d->d_size != orig_size)
104 {
105 printf ("Unexpected data size for orig section %zd\n", idx);
106 return -1;
107 }
108 char *orig_buf = malloc (d->d_size);
109 if (orig_size > 0 && orig_buf == NULL)
110 {
111 printf ("No memory to copy section %zd data\n", idx);
112 return -1;
113 }
114 if (orig_size > 0)
115 memcpy (orig_buf, d->d_buf, orig_size);
116
117 bool forced = false;
118 if (gnu)
119 {
120 int res = elf_compress_gnu (scn, 1, 0);
121 if (res == 0)
122 {
123 forced = true;
124 res = elf_compress_gnu (scn, 1, ELF_CHF_FORCE);
125 }
126 if (res < 0)
127 {
128 printf ("elf_compress_gnu%sfailed for section %zd: %s\n",
129 forced ? " (forced) " : " ",
130 idx, elf_errmsg (-1));
131 return -1;
132 }
133 }
134 else
135 {
136 int res = elf_compress (scn, ELFCOMPRESS_ZLIB, 0);
137 if (res == 0)
138 {
139 forced = true;
140 res = elf_compress (scn, ELFCOMPRESS_ZLIB, ELF_CHF_FORCE);
141 }
142 if (res < 0)
143 {
144 printf ("elf_compress%sfailed for section %zd: %s\n",
145 forced ? " (forced) " : " ",
146 idx, elf_errmsg (-1));
147 return -1;
148 }
149 }
150 GElf_Shdr newmem;
151 GElf_Shdr *newshdr = gelf_getshdr (scn, &newmem);
152 size_t new_size = newshdr->sh_size;
153 d = elf_getdata (scn, NULL);
154 // Don't check this, might depend on zlib implementation.
155 // fprintf (stderr, " new_size: %zd\n", new_size);
156 if (d->d_size != new_size)
157 {
158 printf ("Unexpected data size for compressed section %zd\n",
159 idx);
160 return -1;
161 }
162
163 if (forced && new_size < orig_size)
164 {
165 printf ("section %zd forced to compress, but size smaller\n",
166 idx);
167 return -1;
168 }
169
170 if (! forced && new_size >= orig_size)
171 {
172 printf ("section %zd compressed to bigger size\n",
173 idx);
174 return -1;
175 }
176
177 if (new_size == orig_size
178 && memcmp (orig_buf, d->d_buf, orig_size) == 0)
179 {
180 printf ("section %zd didn't compress\n", idx);
181 return -1;
182 }
183
184 if (gnu)
185 {
186 if (elf_compress_gnu (scn, 0, 0) < 0)
187 {
188 printf ("elf_[un]compress_gnu failed for section %zd: %s\n",
189 idx, elf_errmsg (-1));
190 return -1;
191 }
192 }
193 else
194 {
195 if (elf_compress (scn, 0, 0) < 0)
196 {
197 printf ("elf_[un]compress failed for section %zd: %s\n",
198 idx, elf_errmsg (-1));
199 return -1;
200 }
201 }
202 GElf_Shdr newermem;
203 GElf_Shdr *newershdr = gelf_getshdr (scn, &newermem);
204 size_t newer_size = newershdr->sh_size;
205 d = elf_getdata (scn, NULL);
206 // fprintf (stderr, " newer_size: %zd\n", newer_size);
207 if (d->d_size != newer_size)
208 {
209 printf ("Unexpected data size for compressed section %zd\n",
210 idx);
211 return -1;
212 }
213 if (newer_size != orig_size
214 && memcmp (orig_buf, d->d_buf, orig_size) != 0)
215 {
216 printf ("section %zd didn't correctly uncompress\n", idx);
217 return -1;
218 }
219 free (orig_buf);
220 // Recompress the string table, just to make sure
221 // everything keeps working. See elf_strptr above.
222 if (! gnu && idx == strndx
223 && elf_compress (scn, ELFCOMPRESS_ZLIB, 0) < 0)
224 {
225 printf ("couldn't recompress section header strings: %s\n",
226 elf_errmsg (-1));
227 return -1;
228 }
229 }
230 }
231
232 elf_end (elf);
233 close (fd);
234 }
235
236 return result;
237 }
238