nsschk.c

nsschk.c

/* Compile: gcc -o nsschk nsschk.c -ldl */
/* Blog/info: http://tiny.cc/mozbigsig */

#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
 
void bail(char *msg) {
   fprintf(stderr,"%s\n",msg);
   exit(1);
}
    
int main(int argc, char **argv) {
   /* Use the command argument as the NSS library name,  */
   /* otherwise pick a sensible default for your distro. */
   char *libname = argc>1 ? argv[1] : "/usr/lib64/libnss3.so";
   printf("Using library file: %s\n",libname);
 
   void *nsslib  = dlopen(libname,RTLD_LAZY);
   if (nsslib == NULL) { bail("Can't dlopen() that file"); }
 
   int   (*initfn)(char *dir) = dlsym(nsslib,"NSS_NoDB_Init");
   char *(*getvfn)(void)      = dlsym(nsslib,"NSS_GetVersion");
 
   if (initfn == NULL) { bail("Can't find NSS_NoDB_Init function"); }
   if (getvfn == NULL) { bail("Can't find NSS_GetVersion function"); }
  
   if ((*initfn)(".") != 0) { bail("Failed to initialise NSS"); }
  
   printf("NSS Version: %s\n",(*getvfn)());
   return 0;
}