[hackers] [dwm] do not call signal-unsafe function inside sighanlder || NRK

[git]

commit 6613d9f9a1a5630bab30bc2b70bdc793977073ee
Author:     NRK <n...@disroot.org>
AuthorDate: Thu Jul 14 07:26:40 2022 +0600
Commit:     Hiltjo Posthuma <hil...@codemadness.org>
CommitDate: Fri Jul 15 20:53:58 2022 +0200

    do not call signal-unsafe function inside sighanlder
    
    die() calls vprintf, fputc and exit; none of these are
    async-signal-safe, see `man 7 signal-safety`.

diff --git a/dwm.c b/dwm.c
index b3c43ee..7c0f978 100644
--- a/dwm.c
+++ b/dwm.c
@@ -1541,6 +1541,8 @@ setup(void)
        Atom utf8string;
 
        /* clean up any zombies immediately */
+       if (signal(SIGCHLD, sigchld) == SIG_ERR)
+               die("can't install SIGCHLD handler:");
        sigchld(0);
 
        /* init screen */
@@ -1638,8 +1640,6 @@ showhide(Client *c)
 void
 sigchld(int unused)
 {
-       if (signal(SIGCHLD, sigchld) == SIG_ERR)
-               die("can't install SIGCHLD handler:");
        while (0 < waitpid(-1, NULL, WNOHANG));
 }