unix - How to mount file system without root access using C program? -

i facing 1 problem. requirement is, need mount nfs directory normal user. don't want use root. that, have developed below simple program achieve this. but, not working expected.

my program :

#include<stdio.h> #include<stdlib.h> #include<unistd.h>  void usage( char *progname ) {         printf("usage : %s {mount|umount}\n",progname); }  int main( char argc , char *argv[] ) {         if ( argc != 2 ) {                 usage( argv[0] );                 return exit_failure;         }          if ( strcmp(argv[1] , "mount") == 0 ) {                 execlp("mount", "mount", "192.168.12.3:/home/share", "/home/share", null);         }         else if( strcmp(argv[1] , "umount" ) == 0 ) {                 execlp("umount", "umount", "/home/share", null);         }         else {                 usage( argv[0] );                 return exit_failure;         }          return exit_success; } 

then,

$ cc mount_share.c -o mount 

i set set user id executable file.

$ chmod u+s mount $ ls -lhrt mount -rwsr-xr-x  1 root    root    8.3k jun  4 17:47 mount 

then executed mount normal user, still says error. is,

mount: root can 

as of knowledge, should work.

can point out wrong code?

any other way achieve this?

sudo specially designed purpose - allow unprivileged users run privileged command(to delegate authority). in order solve problem have add setuid(0);, before attempting execlp(3)