use *_not_cancel variants to avoid accidental cancellations with nptl

Signed-off-by: Austin Foxley <austinf@cetoncorp.com>

1 files changed, 45 insertions, 6 deletions

diff --git a/libc/unistd/daemon.c b/libc/unistd/daemon.c
index 741672ec0..c3b563179 100644
--- a/libc/unistd/daemon.c
+++ b/libc/unistd/daemon.c
@@ -46,6 +46,20 @@
 #include <paths.h>
 #include <signal.h>
 #include <unistd.h>
+#include <not-cancel.h>
+#include <errno.h>
+
+#ifdef __UCLIBC_HAS_THREADS_NATIVE__
+#include <sys/stat.h>
+#endif
+
+#ifdef __UCLIBC_HAS_LFS__
+#define STAT stat64
+#define FSTAT fstat64
+#else
+#define STAT stat
+#define FSTAT fstat
+#endif
 
 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_UNIX98)
 
@@ -97,15 +111,40 @@ int daemon(int nochdir, int noclose)
 	if (setsid() == -1)
 		return -1;
 
+#ifndef __UCLIBC_HAS_THREADS_NATIVE__
+	/* Make certain we are not a session leader, or else we
+	 * might reacquire a controlling terminal */
+	if (fork())
+		_exit(0);
+#endif
+
 	if (!nochdir)
 		chdir("/");
 
-	if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
-		dup2(fd, STDIN_FILENO);
-		dup2(fd, STDOUT_FILENO);
-		dup2(fd, STDERR_FILENO);
-		if (fd > 2)
-			close(fd);
+	if (!noclose)
+	{
+		struct STAT st;
+
+		if ((fd = open_not_cancel(_PATH_DEVNULL, O_RDWR, 0)) != -1
+			&& (__builtin_expect (FSTAT (fd, &st), 0) == 0))
+		{
+			if (__builtin_expect (S_ISCHR (st.st_mode), 1) != 0) {
+				dup2(fd, STDIN_FILENO);
+				dup2(fd, STDOUT_FILENO);
+				dup2(fd, STDERR_FILENO);
+				if (fd > 2)
+					close(fd);
+			} else {
+				/* We must set an errno value since no
+				   function call actually failed.  */
+				close_not_cancel_no_status (fd);
+				__set_errno (ENODEV);
+				return -1;
+			}
+		} else {
+			close_not_cancel_no_status (fd);
+			return -1;
+		}
 	}
 	return 0;
 }