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