autofs-5.1.6 - cleanup stale logpri fifo pipes on unlink and exit

From: Ian Kent <raven@themaw.net>

If the unlink and exit option is given then stale fifo pipe files
need to be cleaned up since the entire tree of mounts below autofs
managed directories will be unlinked as well as the autofs mounts
themselves.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 CHANGELOG          |    1 +
 daemon/automount.c |   53 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index fb210905..327a2468 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -48,6 +48,7 @@ xx/xx/2020 autofs-5.1.7
 - improve force unlink option description.
 - remove command fifo on autofs mount fail.
 - add force unlink mounts and exit option.
+- cleanup stale logpri fifo pipes on unlink and exit.
 
 07/10/2019 autofs-5.1.6
 - support strictexpire mount option.
diff --git a/daemon/automount.c b/daemon/automount.c
index 70bb85dd..b9707ef9 100644
--- a/daemon/automount.c
+++ b/daemon/automount.c
@@ -60,7 +60,8 @@ unsigned int nfs_mount_uses_string_options = 0;
 static struct nfs_mount_vers vers, check = {1, 1, 1};
 
 /* autofs fifo name prefix */
-const char *fifodir = AUTOFS_FIFO_DIR "/autofs.fifo";
+#define FIFO_NAME_PREFIX "autofs.fifo"
+const char *fifodir = AUTOFS_FIFO_DIR "/" FIFO_NAME_PREFIX;
 
 const char *global_options;		/* Global option, from command line */
 
@@ -906,6 +907,48 @@ out_free:
 	return ret;
 }
 
+static void cleanup_stale_logpri_fifo_pipes(void)
+{
+	size_t prefix_len = strlen(FIFO_NAME_PREFIX);
+	char *dir = AUTOFS_FIFO_DIR;
+	size_t dir_len = strlen(dir);
+	struct dirent *dent;
+	DIR *dfd;
+	int ret;
+
+	dfd = opendir(dir);
+	if (!dfd) {
+		warn(LOGOPT_ANY, "failed to open fifo dir %s", dir);
+		return;
+	}
+
+	while ((dent = readdir(dfd))) {
+		char fifo_path[PATH_MAX];
+
+		if (!(dent->d_type & DT_FIFO))
+			continue;
+		if (strncmp(FIFO_NAME_PREFIX, dent->d_name, prefix_len))
+			continue;
+		if ((dir_len + 1 + strlen(dent->d_name)) >= PATH_MAX) {
+			warn(LOGOPT_ANY, "fifo path too long for buffer");
+			continue;
+		}
+
+		strcpy(fifo_path, dir);
+		strcat(fifo_path, "/");
+		strcat(fifo_path, dent->d_name);
+
+		ret = unlink(fifo_path);
+		if (ret == -1) {
+			char buf[MAX_ERR_BUF];
+			char *estr = strerror_r(errno, buf, MAX_ERR_BUF);
+			warn(LOGOPT_ANY, "unlink of fifo failed: %s", estr);
+		}
+	}
+
+	closedir(dfd);
+}
+
 static void handle_fifo_message(struct autofs_point *ap, int fd)
 {
 	int ret;
@@ -2695,7 +2738,13 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	if (!(do_force_unlink & UNLINK_AND_EXIT)) {
+	/* If the option to unlink all autofs mounts and exit has
+	 * been given remove logpri fifo pipe files as all the mounts
+	 * will be detached leaving them stale.
+	 */
+	if (do_force_unlink & UNLINK_AND_EXIT)
+		cleanup_stale_logpri_fifo_pipes();
+	else {
 		/*
 		 * Mmm ... reset force unlink umount so we don't also do
 		 * this in future when we receive a HUP signal.