From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Fri, 5 Oct 2012 13:44:37 +0000 (-0400)
Subject: liblttng-ust-fork: override daemon() call
X-Git-Tag: v2.0.6~6
X-Git-Url: https://git.lttng.org/?p=lttng-ust.git;a=commitdiff_plain;h=25297d71946d0c2430c860a00da8236ec09a2475

liblttng-ust-fork: override daemon() call

Fixes #252

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/liblttng-ust-fork/ustfork.c b/liblttng-ust-fork/ustfork.c
index 9ed087c2..af7a6afa 100644
--- a/liblttng-ust-fork/ustfork.c
+++ b/liblttng-ust-fork/ustfork.c
@@ -56,6 +56,34 @@ pid_t fork(void)
 	return retval;
 }
 
+int daemon(int nochdir, int noclose)
+{
+	static int (*plibc_func)(int nochdir, int noclose) = NULL;
+	sigset_t sigset;
+	int retval;
+
+	if (plibc_func == NULL) {
+		plibc_func = dlsym(RTLD_NEXT, "daemon");
+		if (plibc_func == NULL) {
+			fprintf(stderr, "libustfork: unable to find \"daemon\" symbol\n");
+			errno = ENOSYS;
+			return -1;
+		}
+	}
+
+	ust_before_fork(&sigset);
+	/* Do the real daemon call */
+	retval = plibc_func(nochdir, noclose);
+	if (retval == 0) {
+		/* child, parent called _exit() directly */
+		ust_after_fork_child(&sigset);
+	} else {
+		/* on error in the parent */
+		ust_after_fork_parent(&sigset);
+	}
+	return retval;
+}
+
 struct ustfork_clone_info {
 	int (*fn)(void *);
 	void *arg;