comment non-obvious de bruijn sequence code in int parser

[musl] / src / linux / daemon.c

diff --git a/src/linux/daemon.c b/src/linux/daemon.c
index 632d120..afb8019 100644 (file)
--- a/src/linux/daemon.c
+++ b/src/linux/daemon.c
@@ -3,7 +3,16 @@
 
 int daemon(int nochdir, int noclose)
 {
-       int fd;
+       if (!nochdir && chdir("/"))
+               return -1;
+       if (!noclose) {
+               int fd, failed = 0;
+               if ((fd = open("/dev/null", O_RDWR)) < 0) return -1;
+               if (dup2(fd, 0) < 0 || dup2(fd, 1) < 0 || dup2(fd, 2) < 0)
+                       failed++;
+               if (fd > 2) close(fd);
+               if (failed) return -1;
+       }
 
        switch(fork()) {
        case 0: break;
@@ -19,13 +28,5 @@ int daemon(int nochdir, int noclose)
        default: _exit(0);
        }
 
-       if (!nochdir) chdir("/");
-       if (!noclose && (fd = open("/dev/null", O_RDWR)) >= 0) {
-               dup2(fd, 0);
-               dup2(fd, 1);
-               dup2(fd, 2);
-               if (fd > 2) close(fd);
-       }
-
        return 0;
 }