segmentation fault from sprintf function
sorry for my bad english.
I need some help to find an error in my c program, hope someone can tell me what's wrong with my program. I try to make a program to shutdown my linux, but when I using sprintf to combine the command, it's going wrong.
Code:
#include <stdlib.h>#include <stdio.h>
#include <string.h>
#include <unistd.h>
void processval(int sel, char *pass){
char *comm;
switch(sel){
case 1:
sprintf(comm,"echo %s | sudo -S -b poweroff",pass);
system(*comm);
break;
case 2:
sprintf(comm,"echo %s | sudo -S -b reboot",pass);
system(*comm);
break;
case 3:
sprintf(comm,"echo %s | sudo -S -b killall icewm",pass);
system(*comm);
break;
case 4:
system("xscreensaver-command -lock");
break;
}
}
int main(){
int i,sel;
i = 0;
char yrn,c;
system("echo Hello");
char *pass = getpass("Password:");
start:
sel = 0;
printf("Process to:\n");
printf("1.Shutdown\n");
printf("2.Reboot\n");
printf("3.logout\n");
printf("4.lockscreen\n");
printf("5.exit\n\n");
printf("Choose by number:");
scanf("%d",&sel);
printf("\n Are you sure?[y/n]");
choose:
scanf("%c",&yrn);
switch(yrn){
case 'y':
processval(sel,pass);
break;
case 'n':
goto start;
break;
default:goto choose;
}
ends:
return 0;
}
Please help me, to fix the problems. Thanks.
