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BSc-Thesis/thesis/listings/intercept-preload.c

36 lines
770 B
C

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <dlfcn.h>
static void *(*__real_malloc)(size_t);
static int mode = 0;
static void fin(void) {
if (mode > 0) fprintf(stderr, "intercept: stopped\n");
mode = 0;
}
static void init(void) {
if (mode) return;
mode = -1;
if (((__real_malloc) = dlsym(RTLD_NEXT, "malloc")) == NULL) {
fprintf(stderr, "intercept: unable to load symbol '%s': %s",
"malloc", strerror(errno));
return;
}
atexit(fin);
fprintf(stderr, "intercept: intercepting function calls\n");
mode = 1;
}
void *malloc(size_t size) {
init();
// before call to malloc
void *ret = __real_malloc(size);
// after call to malloc
return ret;
}