util.c

   1 /* (C)opyright MMVI Anselm R. Garbe <garbeam at gmail dot com>
   2  * See LICENSE file for license details.
   3  */
   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 erealloc(void *ptr, unsigned int size) {
  34         void *res = realloc(ptr, size);
  35
  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         if(!arg->cmd)
  48                 return;
  49         /* The double-fork construct avoids zombie processes and keeps the code
  50          * clean from stupid signal handlers. */
  51         if(fork() == 0) {
  52                 if(fork() == 0) {
  53                         if(dpy)
  54                                 close(ConnectionNumber(dpy));
  55                         setsid();
  56                         execl(shell, shell, "-c", arg->cmd, (char *)NULL);
  57                         fprintf(stderr, "dwm: execl '%s -c %s'", shell, arg->cmd);
  58                         perror(" failed");
  59                 }
  60                 exit(0);
  61         }
  62         wait(0);
  63 }