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/* Copyright (C) 2015 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
elfutils is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libelf.h>
#include <gelf.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int
main (int argc, char *argv[])
{
int result = 0;
int cnt;
if (argc < 3
|| (strcmp (argv[1], "elf") != 0
&& strcmp (argv[1], "gnu") != 0))
{
printf ("Usage: (elf|gnu) files...\n");
return -1;
}
int gnu;
if (strcmp (argv[1], "gnu") == 0)
gnu = 1;
else
gnu = 0;
elf_version (EV_CURRENT);
for (cnt = 2; cnt < argc; ++cnt)
{
int fd = open (argv[cnt], O_RDONLY);
Elf *elf = elf_begin (fd, ELF_C_READ, NULL);
if (elf == NULL)
{
printf ("%s not usable %s\n", argv[cnt], elf_errmsg (-1));
result = 1;
close (fd);
continue;
}
/* To get the section names. */
size_t strndx;
elf_getshdrstrndx (elf, &strndx);
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (elf, scn)) != NULL)
{
size_t idx = elf_ndxscn (scn);
GElf_Shdr mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &mem);
const char *name = elf_strptr (elf, strndx, shdr->sh_name);
if (shdr->sh_type == SHT_NOBITS
|| (shdr->sh_flags & SHF_ALLOC) != 0)
{
printf ("Cannot compress %zd %s\n", idx, name);
}
else if ((shdr->sh_flags & SHF_COMPRESSED) != 0
|| strncmp (name, ".zdebug", strlen (".zdebug")) == 0)
{
printf ("Already compressed %zd %s\n", idx, name);
}
else
{
size_t orig_size = shdr->sh_size;
printf ("Lets compress %zd %s, size: %" PRId64 "\n",
idx, name, shdr->sh_size);
Elf_Data *d = elf_getdata (scn, NULL);
if (d == NULL)
{
printf ("Couldn't get orig data for section %zd\n", idx);
return -1;
}
/* Make a copy so we can compare after
compression/decompression. */
if (d->d_size != orig_size)
{
printf ("Unexpected data size for orig section %zd\n", idx);
return -1;
}
char *orig_buf = malloc (d->d_size);
if (orig_size > 0 && orig_buf == NULL)
{
printf ("No memory to copy section %zd data\n", idx);
return -1;
}
if (orig_size > 0)
memcpy (orig_buf, d->d_buf, orig_size);
bool forced = false;
if (gnu)
{
int res = elf_compress_gnu (scn, 1, 0);
if (res == 0)
{
forced = true;
res = elf_compress_gnu (scn, 1, ELF_CHF_FORCE);
}
if (res < 0)
{
printf ("elf_compress_gnu%sfailed for section %zd: %s\n",
forced ? " (forced) " : " ",
idx, elf_errmsg (-1));
return -1;
}
}
else
{
int res = elf_compress (scn, ELFCOMPRESS_ZLIB, 0);
if (res == 0)
{
forced = true;
res = elf_compress (scn, ELFCOMPRESS_ZLIB, ELF_CHF_FORCE);
}
if (res < 0)
{
printf ("elf_compress%sfailed for section %zd: %s\n",
forced ? " (forced) " : " ",
idx, elf_errmsg (-1));
return -1;
}
}
GElf_Shdr newmem;
GElf_Shdr *newshdr = gelf_getshdr (scn, &newmem);
size_t new_size = newshdr->sh_size;
d = elf_getdata (scn, NULL);
// Don't check this, might depend on zlib implementation.
// fprintf (stderr, " new_size: %zd\n", new_size);
if (d->d_size != new_size)
{
printf ("Unexpected data size for compressed section %zd\n",
idx);
return -1;
}
if (forced && new_size < orig_size)
{
printf ("section %zd forced to compress, but size smaller\n",
idx);
return -1;
}
if (! forced && new_size >= orig_size)
{
printf ("section %zd compressed to bigger size\n",
idx);
return -1;
}
if (new_size == orig_size
&& memcmp (orig_buf, d->d_buf, orig_size) == 0)
{
printf ("section %zd didn't compress\n", idx);
return -1;
}
if (gnu)
{
if (elf_compress_gnu (scn, 0, 0) < 0)
{
printf ("elf_[un]compress_gnu failed for section %zd: %s\n",
idx, elf_errmsg (-1));
return -1;
}
}
else
{
if (elf_compress (scn, 0, 0) < 0)
{
printf ("elf_[un]compress failed for section %zd: %s\n",
idx, elf_errmsg (-1));
return -1;
}
}
GElf_Shdr newermem;
GElf_Shdr *newershdr = gelf_getshdr (scn, &newermem);
size_t newer_size = newershdr->sh_size;
d = elf_getdata (scn, NULL);
// fprintf (stderr, " newer_size: %zd\n", newer_size);
if (d->d_size != newer_size)
{
printf ("Unexpected data size for compressed section %zd\n",
idx);
return -1;
}
if (newer_size != orig_size
&& memcmp (orig_buf, d->d_buf, orig_size) != 0)
{
printf ("section %zd didn't correctly uncompress\n", idx);
return -1;
}
free (orig_buf);
// Recompress the string table, just to make sure
// everything keeps working. See elf_strptr above.
if (! gnu && idx == strndx
&& elf_compress (scn, ELFCOMPRESS_ZLIB, 0) < 0)
{
printf ("couldn't recompress section header strings: %s\n",
elf_errmsg (-1));
return -1;
}
}
}
elf_end (elf);
close (fd);
}
return result;
}
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