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#define _GNU_SOURCE
#include <dlfcn.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
char tmpbuff[1024];
unsigned long tmppos = 0;
unsigned long tmpallocs = 0;
/*=========================================================
* * interception points
* */
static void * (*myfn_malloc)(size_t size);
static void (*myfn_free)(void *ptr);
static void print_status(void)
{
char buf[4096];
FILE* status = fopen("/proc/self/status", "r");
if (status == NULL)
{
perror("fopen status");
exit(1);
}
FILE* output = fopen("status", "w");
if (output == NULL)
{
perror("fopen output file");
exit(1);
}
while (!feof(status))
{
fgets(&buf, 4096, status);
fprintf(output, "%s", buf);
}
fclose(status);
}
static void init()
{
myfn_malloc = dlsym(RTLD_NEXT, "malloc");
myfn_free = dlsym(RTLD_NEXT, "free");
if (!myfn_malloc || !myfn_free)
{
fprintf(stderr, "Error in `dlsym`: %s\n", dlerror());
exit(1);
}
atexit(print_status);
}
void *malloc(size_t size)
{
static int initializing = 0;
if (myfn_malloc == NULL)
{
if (!initializing)
{
initializing = 1;
init();
initializing = 0;
fprintf(stdout, "jcheck: allocated %lu bytes of temp memory in %lu chunks during initialization\n", tmppos, tmpallocs);
}
else
{
if (tmppos + size < sizeof(tmpbuff))
{
void *retptr = tmpbuff + tmppos;
tmppos += size;
++tmpallocs;
return retptr;
}
else
{
fprintf(stdout, "jcheck: too much memory requested during initialisation - increase tmpbuff size\n");
exit(1);
}
}
}
return myfn_malloc(size);
}
void free(void *ptr)
{
// something wrong if we call free before one of the allocators!
if (myfn_malloc == NULL)
init();
if (ptr >= (void*) tmpbuff && ptr <= (void*)(tmpbuff + tmppos))
fprintf(stdout, "freeing temp memory\n");
else
myfn_free(ptr);
}
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