util.c

   1 /* © 2006-2007 Anselm R. Garbe <garbeam at gmail dot com>
   2  * © 2006-2007 Sander van Dijk <a dot h dot vandijk at gmail dot com>
   3  * See LICENSE file for license details. */
   4 #include "dwm.h"
   5 #include <stdarg.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <sys/wait.h>
   9 #include <unistd.h>
  10
  11 /* extern */
  12
  13 void *
  14 emallocz(unsigned int size) {
  15         void *res = calloc(1, size);
  16
  17         if(!res)
  18                 eprint("fatal: could not malloc() %u bytes\n", size);
  19         return res;
  20 }
  21
  22 void
  23 eprint(const char *errstr, ...) {
  24         va_list ap;
  25
  26         va_start(ap, errstr);
  27         vfprintf(stderr, errstr, ap);
  28         va_end(ap);
  29         exit(EXIT_FAILURE);
  30 }
  31
  32 void
  33 spawn(const char *arg) {
  34         static char *shell = NULL;
  35
  36         if(!shell && !(shell = getenv("SHELL")))
  37                 shell = "/bin/sh";
  38         if(!arg)
  39                 return;
  40         /* The double-fork construct avoids zombie processes and keeps the code
  41          * clean from stupid signal handlers. */
  42         if(fork() == 0) {
  43                 if(fork() == 0) {
  44                         if(dpy)
  45                                 close(ConnectionNumber(dpy));
  46                         setsid();
  47                         execl(shell, shell, "-c", arg, (char *)NULL);
  48                         fprintf(stderr, "dwm: execl '%s -c %s'", shell, arg);
  49                         perror(" failed");
  50                 }
  51                 exit(0);
  52         }
  53         wait(0);
  54 }