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Added tag 3.1 for changeset e1c8bef05e6e
[dwm.git] / util.c
1 /* (C)opyright MMVI-MMVII 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 spawn(Arg *arg) {
34         static char *shell = NULL;
35
36         if(!shell && !(shell = getenv("SHELL")))
37                 shell = "/bin/sh";
38         if(!arg->cmd)
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->cmd, (char *)NULL);
48                         fprintf(stderr, "dwm: execl '%s -c %s'", shell, arg->cmd);
49                         perror(" failed");
50                 }
51                 exit(0);
52         }
53         wait(0);
54 }