Benefits:
* Calling setsid() creates a new process group, which is probably
something you actually want with aisexec.
* Mapping 0/1/2 to /dev/null prevents printfs in the code from causing
problems (even if they're not "supposed" to be there). For example, if
code at some point calls printf() - but file descriptor 1 is an IPC file
descriptor - bad things happen, I suspect.
Notes:
While POSIX defines /dev/null to exist and be a character device, a more
complete patch would check for those properties.
setsid() should probably have its return code checked, but I'm not sure
if doing so would upset things; does it matter (since openais doesn't
call setsid() now) if it fails?
-- Lon
Index: exec/main.c
===================================================================
--- exec/main.c (revision 1480)
+++ exec/main.c (working copy)
@@ -280,7 +280,7 @@
static void aisexec_tty_detach (void)
{
- int lpc;
+ int lpc, fd;
struct rlimit oflimits;
/*
@@ -307,6 +307,24 @@
exit (0);
break;
}
+
+ /* Create new session */
+ setsid();
+
+ /*
+ * Map stdin/out/err to /dev/null.
+ */
+ fd = open("/dev/null", O_RDWR);
+ if (fd >= 0) {
+ /* dup2 to 0 / 1 / 2 (stdin / stdout / stderr) */
+ dup2(fd, STDIN_FILENO); /* 0 */
+ dup2(fd, STDOUT_FILENO); /* 1 */
+ dup2(fd, STDERR_FILENO); /* 2 */
+
+ /* Should be 0, but just in case it isn't... */
+ if (fd > 2)
+ close(fd);
+ }
}
static void aisexec_setscheduler (void)
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