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  * © 2006-2007 Jukka Salmi <jukka at salmi dot ch>
   4  * © 2007 Premysl Hruby <dfenze at gmail dot com>
   5  * © 2007 Szabolcs Nagy <nszabolcs at gmail dot com>
   6  * See LICENSE file for license details. */
   7 #include "dwm.h"
   8 #include <stdarg.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <sys/wait.h>
  12 #include <unistd.h>
  13
  14 /* extern */
  15
  16 void *
  17 emallocz(unsigned int size) {
  18         void *res = calloc(1, size);
  19
  20         if(!res)
  21                 eprint("fatal: could not malloc() %u bytes\n", size);
  22         return res;
  23 }
  24
  25 void
  26 eprint(const char *errstr, ...) {
  27         va_list ap;
  28
  29         va_start(ap, errstr);
  30         vfprintf(stderr, errstr, ap);
  31         va_end(ap);
  32         exit(EXIT_FAILURE);
  33 }
  34
  35 void
  36 spawn(const char *arg) {
  37         static char *shell = NULL;
  38
  39         if(!shell && !(shell = getenv("SHELL")))
  40                 shell = "/bin/sh";
  41         if(!arg)
  42                 return;
  43         /* The double-fork construct avoids zombie processes and keeps the code
  44          * clean from stupid signal handlers. */
  45         if(fork() == 0) {
  46                 if(fork() == 0) {
  47                         if(dpy)
  48                                 close(ConnectionNumber(dpy));
  49                         setsid();
  50                         execl(shell, shell, "-c", arg, (char *)NULL);
  51                         fprintf(stderr, "dwm: execl '%s -c %s'", shell, arg);
  52                         perror(" failed");
  53                 }
  54                 exit(0);
  55         }
  56         wait(0);
  57 }