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/* Copyright (C) 2015 Red Hat, Inc.
Copyright (C) 2024 Mark J. Wielaard <mark@klomp.org>
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 <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libelf.h>
#include <errno.h>
#include <gelf.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
int
main (int argc, char *argv[])
{
int result = 0;
int cnt;
if (argc < 3
|| (strcmp (argv[1], "read") != 0
&& strcmp (argv[1], "mmap") != 0
&& strcmp (argv[1], "mem") != 0))
{
printf ("Usage: (read|mmap|mem) files...\n");
return -1;
}
bool do_read = strcmp (argv[1], "read") == 0;
bool do_mmap = strcmp (argv[1], "mmap") == 0;
bool do_mem = strcmp (argv[1], "mem") == 0;
elf_version (EV_CURRENT);
for (cnt = 2; cnt < argc; ++cnt)
{
int fd = open (argv[cnt], O_RDONLY);
void *map_address = NULL;
size_t map_size = 0;
Elf *elf;
if (do_read)
elf = elf_begin (fd, ELF_C_READ, NULL);
else if (do_mmap)
elf = elf_begin (fd, ELF_C_READ_MMAP, NULL);
else
{
assert (do_mem);
// We mmap the memory ourselves, explicitly PROT_READ | PROT_WRITE
// elf_memory needs writable memory when using elf_compress.
struct stat st;
if (fstat (fd, &st) != 0)
{
printf ("%s cannot stat %s\n", argv[cnt], strerror (errno));
result = 1;
close (fd);
continue;
}
map_size = st.st_size;
map_address = mmap (NULL, map_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE, fd, 0);
if (map_address == MAP_FAILED)
{
printf ("%s cannot mmap %s\n", argv[cnt], strerror (errno));
result = 1;
close (fd);
continue;
}
if (map_size < EI_NIDENT
|| memcmp (map_address, ELFMAG, SELFMAG) != 0)
{
printf ("%s isn't an ELF file\n", argv[cnt]);
result = 1;
munmap (map_address, map_size);
close (fd);
continue;
}
elf = elf_memory (map_address, map_size);
}
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_flags & SHF_COMPRESSED) != 0)
{
/* Real compressed section. */
if (elf_compress (scn, 0, 0) < 0)
{
printf ("elf_compress failed for section %zd: %s\n",
idx, elf_errmsg (-1));
return -1;
}
Elf_Data *d = elf_getdata (scn, NULL);
printf ("%zd: %s, ELF compressed, size: %zx\n",
idx, name, d->d_size);
}
else
{
/* Maybe an old GNU compressed .z section? */
if (name[0] == '.' && name[1] == 'z')
{
if (elf_compress_gnu (scn, 0, 0) < 0)
{
printf ("elf_compress_gnu failed for section %zd: %s\n",
idx, elf_errmsg (-1));
return -1;
}
Elf_Data *d = elf_getdata (scn, NULL);
printf ("%zd: %s, GNU compressed, size: %zx\n",
idx, name, d->d_size);
}
else
printf ("%zd: %s, NOT compressed\n", idx, name);
}
}
elf_end (elf);
close (fd);
if (do_mem)
{
/* Make sure we can still get at the memory. */
if (memcmp (map_address, ELFMAG, SELFMAG) != 0)
{
printf ("%s isn't an ELF file anymore???\n", argv[cnt]);
result = 1;
}
if (munmap (map_address, map_size) != 0)
{
printf ("%s cannot munmap %s\n", argv[cnt], strerror (errno));
result = 1;
}
}
}
return result;
}
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