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/*
* elfextract.c - Extract the loadable program segment from an elf file.
*
* Copyright 1996 Paul Mackerras.
*
* 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; either 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <linux/elf.h>
FILE *fi, *fo;
char *ni, *no;
char buf[65536];
void
rd(void *buf, int len)
{
int nr;
nr = fread(buf, 1, len, fi);
if (nr == len)
return;
if (ferror(fi))
fprintf(stderr, "%s: read error\n", ni);
else
fprintf(stderr, "%s: short file\n", ni);
exit(1);
}
int
main(int ac, char **av)
{
unsigned nb, len, i;
Elf32_Ehdr eh;
Elf32_Phdr ph;
unsigned long phoffset, phsize, prevaddr;
if (ac > 3 || (ac > 1 && av[1][0] == '-')) {
fprintf(stderr, "Usage: %s [elf-file [image-file]]\n", av[0]);
exit(0);
}
fi = stdin;
ni = "(stdin)";
fo = stdout;
no = "(stdout)";
if (ac > 1) {
ni = av[1];
fi = fopen(ni, "rb");
if (fi == NULL) {
perror(ni);
exit(1);
}
}
rd(&eh, sizeof(eh));
if (eh.e_ident[EI_MAG0] != ELFMAG0
|| eh.e_ident[EI_MAG1] != ELFMAG1
|| eh.e_ident[EI_MAG2] != ELFMAG2
|| eh.e_ident[EI_MAG3] != ELFMAG3) {
fprintf(stderr, "%s: not an ELF file\n", ni);
exit(1);
}
fseek(fi, eh.e_phoff, 0);
phsize = 0;
for (i = 0; i < eh.e_phnum; ++i) {
rd(&ph, sizeof(ph));
if (ph.p_type != PT_LOAD)
continue;
if (phsize == 0 || prevaddr == 0) {
phoffset = ph.p_offset;
phsize = ph.p_filesz;
} else
phsize = ph.p_offset + ph.p_filesz - phoffset;
prevaddr = ph.p_vaddr;
}
if (phsize == 0) {
fprintf(stderr, "%s: doesn't have a loadable segment\n", ni);
exit(1);
}
if (ac > 2) {
no = av[2];
fo = fopen(no, "wb");
if (fo == NULL) {
perror(no);
exit(1);
}
}
fseek(fi, phoffset, 0);
for (len = phsize; len != 0; len -= nb) {
nb = len;
if (nb > sizeof(buf))
nb = sizeof(buf);
rd(buf, nb);
if (fwrite(buf, 1, nb, fo) != nb) {
fprintf(stderr, "%s: write error\n", no);
exit(1);
}
}
fclose(fo);
fclose(fi);
exit(0);
}
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