glibc/elf/readlib.c

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/* Copyright (C) 1999, 2000 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.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* 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 <elf.h>
#include <error.h>
#include <link.h>
#include <libintl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <a.out.h>
#include <sys/mman.h>
#include <sys/stat.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-linux.so.2", FLAG_ELF_LIBC6},
{"/lib/ld-linux.so.1", FLAG_ELF_LIBC5}
};
static struct known_names known_libs [] =
{
{"libc.so.6", FLAG_ELF_LIBC6},
{"libc.so.5", FLAG_ELF_LIBC5},
{"libm.so.6", FLAG_ELF_LIBC6},
{"libm.so.5", FLAG_ELF_LIBC5}
};
/* Returns 0 if everything is ok, != 0 in case of error. */
int
process_file (const char *file_name, const char *lib, int *flag, char **soname, int is_link)
{
FILE *file;
struct stat statbuf;
void *file_contents;
int ret;
ElfW(Ehdr) *elf_header;
struct exec *aout_header;
ret = 0;
*flag = FLAG_ANY;
*soname = NULL;
file = fopen (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 (fstat (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 (statbuf.st_size < sizeof (struct exec)
|| statbuf.st_size < sizeof (ElfW(Ehdr)))
{
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
|| N_MAGIC (*aout_header) == QMAGIC)
{
/* 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 (elf_header->e_ident [EI_MAG0] != ELFMAG0
|| elf_header->e_ident [EI_MAG1] != ELFMAG1
|| elf_header->e_ident [EI_MAG2] != ELFMAG2
|| elf_header->e_ident [EI_MAG3] != ELFMAG3)
{
/* The file is neither ELF nor aout. Check if it's a linker script,
like libc.so - otherwise complain. */
int len = statbuf.st_size;
/* Only search the beginning of the file. */
if (len > 512)
len = 512;
if (memmem (file_contents, len, "GROUP", 5) == NULL
&& memmem (file_contents, len, "GNU ld script", 13) == NULL)
error (0, 0, _("%s is not an ELF file - it has the wrong magic bytes at the start.\n"),
file_name);
ret = 1;
goto done;
}
if (process_elf_file (file_name, lib, flag, soname, file_contents))
ret = 1;
done:
/* Clean up allocated memory and resources. */
munmap (file_contents, statbuf.st_size);
fclose (file);
return ret;
}
/* Get architecture specific version of process_elf_file. */
#include "readelflib.c"