Hi Gurus,
need your help,
i am stuck with this piece of code where I try to run exportfs -r from my C code. No error is reported but nothing expected comes out either. Here is what I do: (/etc/exports is modified, which confirms that setuid is working ok)

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
/* getting and setting advanced permissions for the script */
int ruid = getuid();
int euid = geteuid();

strcpy(root_fs, argv[1]);

if (setuid(euid) == -1) {
return 1;
}

fd = fopen("/etc/exports", "r+");
if (fd == NULL) {
printf("Error: can't open file.\n");
setuid(ruid);
return 1;
}

/* Adding the line in /etc/exports */

fprintf(fd, "%s", argv[1]);
fprintf(fd, "%s", " *(rw)");
fprintf(fd, "%s", "\n");

/* Executing exportfs -a */
execlp("/usr/sbin/exportfs","-r",NULL);

// retval = system("/usr/sbin/exportfs -r");

if (retval != 0){
printf("Error in executing exportfs -r");
setuid(ruid);
return 1;
}

setuid(ruid);
fclose(fd);
return 0;
}


Any help will be greatly appreciated