#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1996\
Christopher G. Demetriou. All rights reserved.");
#endif
#ifndef lint
__RCSID("$NetBSD: binpatch.c,v 1.7 2016/09/22 17:08:16 christos Exp $");
#endif
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/inttypes.h>
#include <err.h>
#include <fcntl.h>
#include <limits.h>
#include <nlist.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include "extern.h"
static void usage(void) __dead;
bool replace, verbose;
u_long addr, offset;
char *symbol;
size_t size;
uint64_t val;
static const struct {
const char *name;
int (*check)(const char *, size_t);
int (*findoff)(const char *, size_t, u_long, size_t *, u_long);
} exec_formats[] = {
#ifdef NLIST_AOUT
{ "a.out", check_aout, findoff_aout, },
#endif
#ifdef NLIST_ECOFF
{ "ECOFF", check_ecoff, findoff_ecoff, },
#endif
#ifdef NLIST_ELF32
{ "ELF32", check_elf32, findoff_elf32, },
#endif
#ifdef NLIST_ELF64
{ "ELF64", check_elf64, findoff_elf64, },
#endif
#ifdef NLIST_COFF
{ "COFF", check_coff, findoff_coff, },
#endif
};
int
main(int argc, char *argv[])
{
const char *fname;
struct stat sb;
struct nlist nl[2];
char *mappedfile;
size_t valoff;
void *valp;
uint8_t uval8;
int8_t sval8;
uint16_t uval16;
int16_t sval16;
uint32_t uval32;
int32_t sval32;
uint64_t uval64;
int64_t sval64;
int ch, fd, rv, i, n;
u_long text_start;
setprogname(argv[0]);
text_start = (unsigned long)~0;
while ((ch = getopt(argc, argv, "bwldT:a:s:o:r:v")) != -1)
switch (ch) {
case 'b':
size = sizeof(uint8_t);
break;
case 'w':
size = sizeof(uint16_t);
break;
case 'l':
size = sizeof(uint32_t);
break;
case 'd':
size = sizeof(uint64_t);
break;
case 'a':
if (addr != 0 || symbol != NULL)
errx(EXIT_FAILURE,
"only one address/symbol allowed");
addr = strtoul(optarg, NULL, 0);
break;
case 's':
if (addr != 0 || symbol != NULL)
errx(EXIT_FAILURE,
"only one address/symbol allowed");
symbol = optarg;
break;
case 'o':
if (offset != 0)
err(EXIT_FAILURE,
"only one offset allowed");
offset = strtoul(optarg, NULL, 0);
break;
case 'r':
replace = true;
val = strtoull(optarg, NULL, 0);
break;
case 'v':
verbose = true;
break;
case 'T':
text_start = strtoul(optarg, NULL, 0);
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (argc != 1)
usage();
if (addr == 0 && symbol == NULL) {
warnx("no address or symbol specified");
usage();
}
if (size == 0)
size = sizeof(uint32_t);
fname = argv[0];
if ((fd = open(fname, replace ? O_RDWR : O_RDONLY, 0)) == -1)
err(EXIT_FAILURE, "open %s", fname);
if (symbol != NULL) {
nl[0].n_name = symbol;
nl[1].n_name = NULL;
if ((rv = __fdnlist(fd, nl)) != 0)
errx(EXIT_FAILURE, "could not find symbol %s in %s",
symbol, fname);
addr = nl[0].n_value;
if (verbose)
fprintf(stderr, "got symbol address 0x%lx from %s\n",
addr, fname);
}
addr += offset * size;
if (fstat(fd, &sb) == -1)
err(EXIT_FAILURE, "fstat %s", fname);
if (sb.st_size != (ssize_t)sb.st_size)
errx(EXIT_FAILURE, "%s too big to map", fname);
if ((mappedfile = mmap(NULL, sb.st_size,
replace ? PROT_READ | PROT_WRITE : PROT_READ,
MAP_FILE | MAP_SHARED, fd, 0)) == (char *)-1)
err(EXIT_FAILURE, "mmap %s", fname);
if (verbose)
fprintf(stderr, "mapped %s\n", fname);
n = __arraycount(exec_formats);
for (i = 0; i < n; i++) {
if ((*exec_formats[i].check)(mappedfile, sb.st_size) == 0)
break;
}
if (i == n)
errx(EXIT_FAILURE, "%s: unknown executable format", fname);
if (verbose) {
fprintf(stderr, "%s is an %s binary\n", fname,
exec_formats[i].name);
if (text_start != (u_long)~0)
fprintf(stderr, "kernel text loads at 0x%lx\n",
text_start);
}
if ((*exec_formats[i].findoff)(mappedfile, sb.st_size,
addr, &valoff, text_start) != 0)
errx(EXIT_FAILURE, "couldn't find file offset for %s in %s",
symbol != NULL ? nl[0].n_name : "address" , fname);
valp = mappedfile + valoff;
if (symbol)
printf("%s(0x%lx): ", symbol, addr);
else
printf("0x%lx: ", addr);
switch (size) {
case sizeof(uint8_t):
uval8 = *(uint8_t *)valp;
sval8 = *(int8_t *)valp;
printf("0x%02" PRIx8 " (%" PRIu8, uval8, uval8);
if (sval8 < 0)
printf("/%" PRId8, sval8);
printf(")");
break;
case sizeof(uint16_t):
uval16 = *(uint16_t *)valp;
sval16 = *(int16_t *)valp;
printf("0x%04" PRIx16 " (%" PRIu16, uval16, uval16);
if (sval16 < 0)
printf("/%" PRId16, sval16);
printf(")");
break;
case sizeof(uint32_t):
uval32 = *(uint32_t *)valp;
sval32 = *(int32_t *)valp;
printf("0x%08" PRIx32 " (%" PRIu32, uval32, uval32);
if (sval32 < 0)
printf("/%" PRId32, sval32);
printf(")");
break;
case sizeof(uint64_t):
uval64 = *(uint64_t *)valp;
sval64 = *(int64_t *)valp;
printf("0x%016" PRIx64 " (%" PRIu64, uval64, uval64);
if (sval64 < 0)
printf("/%" PRId64, sval64);
printf(")");
break;
}
printf(", at offset %#lx in %s\n", (unsigned long)valoff, fname);
if (!replace)
goto done;
printf("new value: ");
switch (size) {
case sizeof(uint8_t):
uval8 = (uint8_t)val;
sval8 = (int8_t)val;
printf("0x%02" PRIx8 " (%" PRIu8, uval8, uval8);
if (sval8 < 0)
printf("/%" PRId8, sval8);
printf(")");
*(uint8_t *)valp = uval8;
break;
case sizeof(uint16_t):
uval16 = (uint16_t)val;
sval16 = (int16_t)val;
printf("0x%04" PRIx16 " (%" PRIu16, uval16, uval16);
if (sval16 < 0)
printf("/%" PRId16, sval16);
printf(")");
*(uint16_t *)valp = uval16;
break;
case sizeof(uint32_t):
uval32 = (uint32_t)val;
sval32 = (int32_t)val;
printf("0x%08" PRIx32 " (%" PRIu32, uval32, uval32);
if (sval32 < 0)
printf("/%" PRId32, sval32);
printf(")");
*(uint32_t *)valp = uval32;
break;
case sizeof(uint64_t):
uval64 = (uint64_t)val;
sval64 = (int64_t)val;
printf("0x%016" PRIx64 " (%" PRIu64, uval64, uval64);
if (sval64 < 0)
printf("/%" PRId64, sval64);
printf(")");
*(uint64_t *)valp = uval64;
break;
}
printf("\n");
done:
munmap(mappedfile, sb.st_size);
close(fd);
if (verbose)
fprintf(stderr, "exiting\n");
exit(EXIT_SUCCESS);
}
static void
usage(void)
{
fprintf(stderr,
"Usage: %s [-b|-w|-l|-d] [-a address | -s symbol] [-o offset]"
" [-r value] [-T text_start] [-v] binary\n", getprogname());
exit(EXIT_FAILURE);
}
