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#include "substitute.h"
#include "substitute-internal.h"
#include <stdio.h>
#include <search.h>
#include <unistd.h>
#include <errno.h>
static pid_t (*old_getpid)();
static pid_t hook_getpid() {
return old_getpid() * 2;
}
static int hook_hcreate(size_t nel) {
return (int) nel;
}
static size_t (*old_fwrite)(const void *restrict, size_t, size_t, FILE *restrict);
static size_t hook_fwrite(const void *restrict ptr, size_t size, size_t nitems,
FILE *restrict stream) {
size_t ret = old_fwrite(ptr, size, nitems, stream);
old_fwrite("*hic*\n", 1, 6, stream);
return ret;
}
__attribute__((noinline))
void break_before() {
__asm__ volatile("");
}
__attribute__((noinline))
void break_after() {
__asm__ volatile("");
}
__attribute__((section("__TEST,__foo"), noinline))
static int my_own_function(int x) {
return x + 4;
}
static int hook_my_own_function(int x) {
return x + 5;
}
static const struct substitute_function_hook hooks[] = {
{my_own_function, hook_my_own_function, NULL},
{getpid, hook_getpid, &old_getpid},
{hcreate, hook_hcreate, NULL},
{fwrite, hook_fwrite, &old_fwrite},
};
int main() {
#ifdef TARGET_DIS_SUPPORTED
for (size_t i = 0; i < sizeof(hooks)/sizeof(*hooks); i++) {
uintptr_t p = (uintptr_t) hooks[i].function;
uint32_t *insns = (void *) (p & ~1);
printf("<%zd: ptr=%p insns=0x%08x, 0x%08x, 0x%08x\n",
i, hooks[i].function,
insns[0], insns[1], insns[2]);
}
printf("getpid() => %d\n", getpid());
break_before();
int ret = substitute_hook_functions(hooks, sizeof(hooks)/sizeof(*hooks),
NULL, 0);
break_after();
int e = errno;
printf("ret = %d\n", ret);
printf("errno = %d\n", e);
printf("getpid() => %d\n", getpid());
printf("hcreate() => %d\n", hcreate(42));
printf("my_own_function() => %d\n", my_own_function(0));
#else
(void) hooks;
printf("can't test this here\n");
#endif
}
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