deamonize: restore detection of errors

Keep forked environment for daemon more strick and check even
for nearly impossible to happen errors.

2 files changed, 24 insertions, 11 deletions

diff --git a/daemons/clvmd/clvmd.c b/daemons/clvmd/clvmd.c
index 46f5f4408..9dbda89cc 100644
--- a/daemons/clvmd/clvmd.c
+++ b/daemons/clvmd/clvmd.c
@@ -1111,12 +1111,18 @@ static void be_daemon(int timeout)
 	}
 
 	/* Detach ourself from the calling environment */
-	(void) dup2(devnull, STDIN_FILENO);
-	(void) dup2(devnull, STDOUT_FILENO);
-	(void) dup2(devnull, STDERR_FILENO);
+	if ((dup2(devnull, STDIN_FILENO) == -1) ||
+	    (dup2(devnull, STDOUT_FILENO) == -1) ||
+	    (dup2(devnull, STDERR_FILENO) == -1)) {
+		perror("Error setting terminal FDs to /dev/null");
+		log_error("Error setting terminal FDs to /dev/null: %m");
+		exit(5);
+	}
 
-	if (devnull > STDERR_FILENO)
-		(void) close(devnull);
+	if ((devnull > STDERR_FILENO) && close(devnull)) {
+		log_sys_error("close", "/dev/null");
+		exit(7);
+	}
 
 	if (chdir("/")) {
 		log_error("Error setting current directory to /: %m");
diff --git a/libdaemon/server/daemon-server.c b/libdaemon/server/daemon-server.c
index 0950c2e16..2ffdf402d 100644
--- a/libdaemon/server/daemon-server.c
+++ b/libdaemon/server/daemon-server.c
@@ -377,15 +377,22 @@ static void _daemonise(daemon_state s)
 		exit(WEXITSTATUS(child_status));
 	}
 
-	if (chdir("/"))
+	if (chdir("/")) {
+		perror("Cannot chdir to /");
 		exit(1);
+	}
 
-	(void) dup2(fd, STDIN_FILENO);
-	(void) dup2(fd, STDOUT_FILENO);
-	(void) dup2(fd, STDERR_FILENO);
+	if ((dup2(fd, STDIN_FILENO) == -1) ||
+	    (dup2(fd, STDOUT_FILENO) == -1) ||
+	    (dup2(fd, STDERR_FILENO) == -1)) {
+		perror("Error setting terminal FDs to /dev/null");
+		exit(2);
+	}
 
-	if (fd > STDERR_FILENO)
-		(void) close(fd);
+	if ((fd > STDERR_FILENO) && close(fd)) {
+		perror("Failed to close /dev/null descriptor");
+		exit(3);
+	}
 
 	/* Switch to sysconf(_SC_OPEN_MAX) ?? */
 	if (getrlimit(RLIMIT_NOFILE, &rlim) < 0)