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/* This file is part of centaur.
*
* centaur is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as
* published by the Free Software Foundation.
* centaur 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 centaur. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <libelfu/libelfu.h>
#include "elfhandle.h"
static void printUsage(char *progname)
{
printf("Usage: %s -i <inputfile> [OPTIONS]\n", progname);
printf("\n"
"Options, executed in order given:\n"
" -h, --help Print this help message\n"
"\n"
" -i, --input infile Load new ELF file (must be first command)\n"
"\n"
" -c, --check Do a few sanity checks and print any errors\n"
" -d, --dump Dump current model state (debug only)\n"
" --reladd obj.o Insert object file contents\n"
" --detour from,to Write a jump to <to> at <from>\n"
" -o, --output outfile Where to write the modified ELF file to\n"
"\n");
}
int main(int argc, char **argv)
{
ELFHandles hIn = { 0 };
int exitval = EXIT_SUCCESS;
char *progname = argv[0];
int c;
int option_index = 0;
ElfuElf *me = NULL;
static struct option long_options[] = {
{"help", 0, 0, 'h'},
{"check", 0, 0, 'c'},
{"dump", 0, 0, 'd'},
{"input", 1, 0, 'i'},
{"output", 1, 0, 'o'},
{"reladd", 1, 0, 10001},
{"detour", 1, 0, 10002},
{NULL, 0, NULL, 0}
};
if (argc < 3) {
printUsage(progname);
goto EXIT;
}
/* Is libelf alive and well? */
if (elf_version(EV_CURRENT) == EV_NONE) {
fprintf(stderr, "libelf init error: %s\n", elf_errmsg(-1));
}
/* Parse and and execute user commands */
while ((c = getopt_long(argc, argv, "hcdi:o:",
long_options, &option_index)) != -1) {
switch (c) {
case 'h':
printUsage(progname);
goto EXIT;
case 'c':
if (!me) {
goto ERR_NO_INPUT;
} else {
printf("Checking model validity...\n");
elfu_mCheck(me);
}
break;
case 'd':
if (!me) {
goto ERR_NO_INPUT;
} else {
elfu_mDumpElf(me);
}
break;
case 'i':
if (me) {
elfu_mElfDestroy(me);
}
printf("Opening input file %s.\n", optarg);
openElf(&hIn, optarg, ELF_C_READ);
if (!hIn.e) {
printf("Error: Failed to open input file. Aborting.\n");
exitval = EXIT_FAILURE;
goto EXIT;
}
me = elfu_mFromElf(hIn.e);
closeElf(&hIn);
if (!me) {
printf("Error: Failed to load model, aborting.\n");
goto EXIT;
}
break;
case 'o':
if (!me) {
goto ERR_NO_INPUT;
} else {
ELFHandles hOut = { 0 };
printf("Writing modified file to %s.\n", optarg);
openElf(&hOut, optarg, ELF_C_WRITE);
if (!hOut.e) {
printf("Failed to open output file. Aborting.\n");
closeElf(&hOut);
exitval = EXIT_FAILURE;
goto EXIT;
}
elfu_mToElf(me, hOut.e);
if (elf_update(hOut.e, ELF_C_WRITE) < 0) {
fprintf(stderr, "elf_update() failed: %s\n", elf_errmsg(-1));
}
closeElf(&hOut);
}
break;
case 10001:
if (!me) {
goto ERR_NO_INPUT;
} else {
ELFHandles hRel = { 0 };
ElfuElf *mrel = NULL;
openElf(&hRel, optarg, ELF_C_READ);
if (!hRel.e) {
printf("--reladd: Failed to open file for --reladd, aborting.\n");
closeElf(&hRel);
goto ERR;
}
mrel = elfu_mFromElf(hRel.e);
closeElf(&hRel);
if (!mrel) {
printf("--reladd: Failed to load model for --reladd, aborting.\n");
goto ERR;
} else {
printf("--reladd: Injecting %s...\n", optarg);
if (elfu_mCheck(mrel)) {
printf("--reladd: Check for input file failed.\n");
elfu_mElfDestroy(mrel);
goto ERR;
}
if (elfu_mReladd(me, mrel)) {
printf("--reladd: Failed.\n");
elfu_mElfDestroy(mrel);
goto ERR;
}
printf("--reladd: Injected %s.\n", optarg);
elfu_mElfDestroy(mrel);
}
}
break;
case 10002:
if (!me) {
goto ERR_NO_INPUT;
} else {
GElf_Addr from;
GElf_Addr to;
char *second;
strtok_r(optarg, ",", &second);
printf("--detour: From '%s' to '%s'\n", optarg, second);
from = strtoul(optarg, NULL, 0);
if (from == 0) {
from = elfu_mSymtabLookupAddrByName(me, me->symtab, optarg);
}
if (from == 0) {
printf("--detour: Cannot parse argument 1, aborting.\n");
goto ERR;
}
printf("--detour: From %x\n", (unsigned)from);
to = strtoul(second, NULL, 0);
if (to == 0) {
to = elfu_mSymtabLookupAddrByName(me, me->symtab, second);
}
if (to == 0) {
printf("--detour: Cannot parse argument 2, aborting.\n");
goto ERR;
}
printf("--detour: To %x\n", (unsigned)to);
elfu_mDetour(me, from, to);
}
break;
case '?':
default:
printUsage(progname);
goto EXIT;
}
}
while (optind < argc) {
optind++;
}
EXIT:
if (me) {
elfu_mElfDestroy(me);
}
if (hIn.e) {
closeElf(&hIn);
}
return (exitval);
ERR_NO_INPUT:
printf("Error: No input file opened. Aborting.\n");
ERR:
exitval = EXIT_FAILURE;
goto EXIT;
}
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