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#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <linux/elf.h>
#include <string.h>
int main(int argc, char **argv)
{
int fd;
struct stat sbuf;
size_t filesize;
void * addr;
struct elf32_hdr * hdr;
Elf32_Shdr * shdr;
int i;
u_long strtab = 0;
u_long symtab = 0;
u_long symtab_len = 0;
char buf[1024];
char * debug_filename = NULL;
if (argc<2) {
fprintf(stderr, "Usage: %s [options] <program> [<arguments>]\n", argv[0]);
exit(1);
}
while ((argv[1][0] == '-') && argv[1][1] && !argv[1][2]) {
switch(argv[1][1]) {
case 'o':
debug_filename = argv[2];
argc--; argv++;
break;
default:
fprintf(stderr, "Unknown option: '%c'\n", argv[1][1]);
}
argc--; argv++;
}
if (argc<2) {
fprintf(stderr, "Usage: %s [options] <program> [<arguments>]\n", argv[0]);
exit(1);
}
fd = open(argv[1], O_RDONLY);
if (fd<0) {
fprintf(stderr, "Can't open \"%s\" for reading: %s\n", argv[1], sys_errlist[errno]);
exit(1);
}
if (fstat(fd, &sbuf)<0) {
fprintf(stderr, "Can't stat \"%s\": %s\n", argv[1], sys_errlist[errno]);
exit(1);
}
filesize = sbuf.st_size;
if (filesize < sizeof(struct elf32_hdr)) {
fprintf(stderr, "\"%s\" is not an ELF object\n", argv[1]);
exit(1);
}
addr = mmap(NULL, filesize, PROT_READ, MAP_SHARED, fd, 0);
if (!addr) {
fprintf(stderr, "Can't mmap \"%s\": %s\n", argv[1], sys_errlist[errno]);
exit(1);
}
if (debug_filename) {
setenv("LTRACE_FILENAME", debug_filename, 1);
printf("LTRACE_FILENAME=%s\n", debug_filename);
}
/*
* Tengo que decirle a libtrace:
* - Comienzo y tamanno de '.dynsym' LTRACE_SYMTAB_ADDR, LTRACE_SYMTAB_SIZE
* - Comienzo de '.dynstr' LTRACE_STRTAB_ADDR
* - Comienzo y tamanno de '.got' LTRACE_GOT_ADDR, LTRACE_GOT_SIZE
*
* Todo ello especificado en decimal (por elegir algo)
*/
hdr = addr;
if (strncmp(hdr->e_ident, ELFMAG, SELFMAG)) {
fprintf(stderr, "%s is not an ELF object\n", argv[1]);
exit(1);
}
for(i=0; i<hdr->e_shnum; i++) {
shdr = addr + hdr->e_shoff + i*hdr->e_shentsize;
if (shdr->sh_type == SHT_DYNSYM) {
if (!symtab) {
symtab = shdr->sh_addr;
symtab_len = shdr->sh_size;
}
}
if (shdr->sh_type == SHT_STRTAB) {
if (!strtab) {
strtab = shdr->sh_addr;
}
}
}
if (!symtab) {
fprintf(stderr, "No .dynsym in file. Not dynamically linked?\n");
exit(1);
}
if (!strtab) {
fprintf(stderr, "No .dynstr in file. Not dynamically linked?\n");
exit(1);
}
sprintf(buf,"%lu", symtab);
printf("LTRACE_SYMTAB=%lu\n", symtab);
setenv("LTRACE_SYMTAB", buf, 1);
sprintf(buf,"%lu", symtab_len);
printf("LTRACE_SYMTAB_LEN=%lu\n", symtab_len);
setenv("LTRACE_SYMTAB_LEN", buf, 1);
sprintf(buf,"%lu", strtab);
printf("LTRACE_STRTAB=%lu\n", strtab);
setenv("LTRACE_STRTAB", buf, 1);
setenv("LD_PRELOAD", TOPDIR "/lib/libtrace.so.1", 1);
execve(argv[1], &argv[1], environ);
fprintf(stderr, "Couldn't execute \"%s\": %s\n", argv[1], sys_errlist[errno]);
exit(1);
}
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