/*
 * (c) Bernd 'Aard' Wachter, <bwachter@lart.info>
 * You may use and redistribute this file under the terms and conditions
 * of the GNU GPL v2
 *
 * Install:
 * - Compile with cc sus.c -o sus
 * - Copy sus into some directory in your searchpath (e.g. /usr/bin)
 * - Create links named sus_disk, sus_foo, ... or disk, foo, ... to sus 
 *
 * Usage: 
 * - call `sus disk' or sus_disk or disk or sus_foo, [...]
 *
 */
 
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>

#define STATE_PATH "/sys/power/state"

void msg(char *msg){
  write(1,msg,strlen(msg));
}

int wrstate(char *gov){
  int fd;
  if ((fd=open(STATE_PATH, O_WRONLY))==-1){
    msg("Cannot open state file\n");
    return -1;
  }
  write(fd,gov,strlen(gov));
  if (close(fd)==-1) {
    msg("Problem closing state file\n");
    return -1;
  }
  return 0;
}

int main(int argc, char** argv) {
  setuid(geteuid());
  sync();
  if (!strncmp(argv[0],"sus_", 4)) {
    msg("Suspending to ");
    msg(argv[0]+4);
    msg("\n");
    if (wrstate(argv[0]+4)==-1) return -1;
  } else if (argv[1]!=0){
    msg("Suspending to ");
    msg(argv[1]);
    msg("\n");
    if (wrstate(argv[1])==-1) return -1;
  } else { 
    msg("Suspending to ");
    msg(argv[0]);
    msg("\n");
    if (wrstate(argv[0])==-1) return -1;
  }
  return 0;
}