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/* Copyright (C) 1999-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andreas Jaeger <aj@suse.de>, 1999 and
Jakub Jelinek <jakub@redhat.com>, 1999.
This program 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; version 2 of the License, or
(at your option) any later version.
This program 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 <https://www.gnu.org/licenses/>. */
/* The code in this file and in readelflib is a heavily simplified
version of the readelf program that's part of the current binutils
development version. Besides the simplification, it has also been
modified to read some other file formats. */
#include <a.out.h>
#include <elf.h>
#include <error.h>
#include <libintl.h>
#include <link.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <gnu/lib-names.h>
#include <ldconfig.h>
#define Elf32_CLASS ELFCLASS32
#define Elf64_CLASS ELFCLASS64
struct known_names
{
const char *soname;
int flag;
};
static struct known_names interpreters[] =
{
{ "/lib/" LD_SO, FLAG_ELF_LIBC6 },
#ifdef SYSDEP_KNOWN_INTERPRETER_NAMES
SYSDEP_KNOWN_INTERPRETER_NAMES
#endif
};
static struct known_names known_libs[] =
{
{ LIBC_SO, FLAG_ELF_LIBC6 },
{ LIBM_SO, FLAG_ELF_LIBC6 },
#ifdef SYSDEP_KNOWN_LIBRARY_NAMES
SYSDEP_KNOWN_LIBRARY_NAMES
#endif
};
/* Check if string corresponds to a GDB Python file. */
static bool
is_gdb_python_file (const char *name)
{
size_t len = strlen (name);
return len > 7 && strcmp (name + len - 7, "-gdb.py") == 0;
}
/* Returns 0 if everything is ok, != 0 in case of error. */
int
process_file (const char *real_file_name, const char *file_name,
const char *lib, int *flag, unsigned int *osversion,
char **soname, int is_link, struct stat64 *stat_buf)
{
FILE *file;
struct stat64 statbuf;
void *file_contents;
int ret;
ElfW(Ehdr) *elf_header;
struct exec *aout_header;
ret = 0;
*flag = FLAG_ANY;
*soname = NULL;
file = fopen (real_file_name, "rb");
if (file == NULL)
{
/* No error for stale symlink. */
if (is_link && strstr (file_name, ".so") != NULL)
return 1;
error (0, 0, _("Input file %s not found.\n"), file_name);
return 1;
}
if (fstat64 (fileno (file), &statbuf) < 0)
{
error (0, 0, _("Cannot fstat file %s.\n"), file_name);
fclose (file);
return 1;
}
/* Check that the file is large enough so that we can access the
information. We're only checking the size of the headers here. */
if ((size_t) statbuf.st_size < sizeof (struct exec)
|| (size_t) statbuf.st_size < sizeof (ElfW(Ehdr)))
{
if (statbuf.st_size == 0)
error (0, 0, _("File %s is empty, not checked."), file_name);
else
{
char buf[SELFMAG];
size_t n = MIN (statbuf.st_size, SELFMAG);
if (fread (buf, n, 1, file) == 1 && memcmp (buf, ELFMAG, n) == 0)
error (0, 0, _("File %s is too small, not checked."), file_name);
}
fclose (file);
return 1;
}
file_contents = mmap (0, statbuf.st_size, PROT_READ, MAP_SHARED,
fileno (file), 0);
if (file_contents == MAP_FAILED)
{
error (0, 0, _("Cannot mmap file %s.\n"), file_name);
fclose (file);
return 1;
}
/* First check if this is an aout file. */
aout_header = (struct exec *) file_contents;
if (N_MAGIC (*aout_header) == ZMAGIC
#ifdef QMAGIC /* Linuxism. */
|| N_MAGIC (*aout_header) == QMAGIC
#endif
)
{
/* Aout files don't have a soname, just return the name
including the major number. */
char *copy, *major, *dot;
copy = xstrdup (lib);
major = strstr (copy, ".so.");
if (major)
{
dot = strstr (major + 4, ".");
if (dot)
*dot = '\0';
}
*soname = copy;
*flag = FLAG_LIBC4;
goto done;
}
elf_header = (ElfW(Ehdr) *) file_contents;
if (memcmp (elf_header->e_ident, ELFMAG, SELFMAG) != 0)
{
/* The file is neither ELF nor aout. Check if it's a linker
script, like libc.so - otherwise complain. Only search the
beginning of the file. */
size_t len = MIN (statbuf.st_size, 512);
if (memmem (file_contents, len, "GROUP", 5) == NULL
&& memmem (file_contents, len, "GNU ld script", 13) == NULL
&& !is_gdb_python_file (file_name))
error (0, 0, _("%s is not an ELF file - it has the wrong magic bytes at the start.\n"),
file_name);
ret = 1;
}
/* Libraries have to be shared object files. */
else if (elf_header->e_type != ET_DYN)
ret = 1;
else if (process_elf_file (file_name, lib, flag, osversion, soname,
file_contents, statbuf.st_size))
ret = 1;
done:
/* Clean up allocated memory and resources. */
munmap (file_contents, statbuf.st_size);
fclose (file);
*stat_buf = statbuf;
return ret;
}
/* Returns made up soname if lib doesn't have explicit DT_SONAME. */
char *
implicit_soname (const char *lib, int flag)
{
char *soname = xstrdup (lib);
if ((flag & FLAG_TYPE_MASK) != FLAG_LIBC4)
return soname;
/* Aout files don't have a soname, just return the name
including the major number. */
char *major = strstr (soname, ".so.");
if (major)
{
char *dot = strstr (major + 4, ".");
if (dot)
*dot = '\0';
}
return soname;
}
/* Get architecture specific version of process_elf_file. */
#include <readelflib.c>
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