[hackers] [scroll] move signal handling before fork to avoid race with sigchild || Jan Klemkow

[git]

commit d40d23e29abf05092af051831c400a220c41ffb7
Author:     Jan Klemkow <j.klem...@wemelug.de>
AuthorDate: Tue Apr 14 21:33:11 2020 +0200
Commit:     Jan Klemkow <j.klem...@wemelug.de>
CommitDate: Tue Apr 14 21:33:11 2020 +0200

    move signal handling before fork to avoid race with sigchild

diff --git a/scroll.c b/scroll.c
index a560999..cf12ff3 100644
--- a/scroll.c
+++ b/scroll.c
@@ -415,6 +415,11 @@ main(int argc, char *argv[])
        if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0)
                die("ioctl:");
 
+       if (signal(SIGCHLD, sigchld) == SIG_ERR)
+               die("signal:");
+       if (signal(SIGWINCH, sigwinch) == SIG_ERR)
+               die("signal:");
+
        child = forkpty(&mfd, NULL, &dfl, &ws);
        if (child == -1)
                die("forkpty:");
@@ -441,11 +446,6 @@ main(int argc, char *argv[])
                die("pledge:");
 #endif
 
-       if (signal(SIGCHLD, sigchld) == SIG_ERR)
-               die("signal:");
-       if (signal(SIGWINCH, sigwinch) == SIG_ERR)
-               die("signal:");
-
        struct termios new = dfl;
        cfmakeraw(&new);
        new.c_cc[VMIN ] = 1;    /* return read if at least one byte in buffer */