/*
 * ISA 563, Spring 2011
 * Copyleft by Muhammad Abdulla
 */

#include <stdio.h>

#define __USE_GNU
#include <dlfcn.h>

/*
 * ifile.c -- demonstrates interposition of file operations
 */

FILE *fopen(const char *path, const char *mode)
{
   static FILE * (*func)();

   if(!func) {
      func = (FILE *(*)()) dlsym(RTLD_NEXT, "fopen");
   }

   printf("fopen is called with parameters: \"%s\", \"%s\"\n", path, mode);     

   return(func(path, mode));
}

char *fgets(char *buf, int size, FILE *fp)
{
   static char * (*func)();
   char *s;

   if(!func) {
      func = (char *(*)()) dlsym(RTLD_NEXT, "fgets");
   }

   printf("fgets is called with size: %d\n", size);     

   s = func(buf, size, fp);

   printf("fgets returned with string: %s", s);     

   return s;
}

int fputs(const char *buf, FILE *fp)
{
   static int (*func)();
   int n;

   if(!func) {
      func = (int (*)()) dlsym(RTLD_NEXT, "fputs");
   }

   printf("fputs is called with string: \"%s\"\n", buf);     

   n = func(buf, fp);

   return n;
}