util.c

   1 /*
   2  * (C)opyright MMVI Anselm R. Garbe <garbeam at gmail dot com>
   3  * See LICENSE file for license details.
   4  */
   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 erealloc(void *ptr, unsigned int size) {
  35         void *res = realloc(ptr, size);
  36         if(!res)
  37                 eprint("fatal: could not malloc() %u bytes\n", size);
  38         return res;
  39 }
  40
  41 void
  42 spawn(Arg *arg) {
  43         static char *shell = NULL;
  44
  45         if(!shell && !(shell = getenv("SHELL")))
  46                 shell = "/bin/sh";
  47
  48         if(!arg->cmd)
  49                 return;
  50         /* The double-fork construct avoids zombie processes and keeps the code
  51          * clean from stupid signal handlers. */
  52         if(fork() == 0) {
  53                 if(fork() == 0) {
  54                         if(dpy)
  55                                 close(ConnectionNumber(dpy));
  56                         setsid();
  57                         execl(shell, shell, "-c", arg->cmd, (char *)NULL);
  58                         fprintf(stderr, "dwm: execl '%s -c %s'", shell, arg->cmd);
  59                         perror(" failed");
  60                 }
  61                 exit(0);
  62         }
  63         wait(0);
  64 }