1 files changed, 118 insertions, 0 deletions
diff --git a/support/junction/export-cache.c b/support/junction/export-cache.c
new file mode 100644
index 0000000..4e578c9
--- /dev/null
+++ b/support/junction/export-cache.c
@@ -0,0 +1,118 @@
+/**
+ * @file support/junction/export-cache.c
+ * @brief Try to flush NFSD's exports cache
+ */
+
+/*
+ * Copyright 2011, 2018 Oracle.  All rights reserved.
+ *
+ * This file is part of nfs-utils.
+ *
+ * nfs-utils is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2.0 as
+ * published by the Free Software Foundation.
+ *
+ * nfs-utils is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2.0 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2.0 along with nfs-utils.  If not, see:
+ *
+ *	http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+
+
+#include "junction.h"
+#include "xlog.h"
+
+/**
+ * Ordered list of proc files to poke when requesting an NFSD cache flush
+ */
+static const char *junction_proc_files[] = {
+	"/proc/net/rpc/auth.unix.ip/flush",
+	"/proc/net/rpc/auth.unix.gid/flush",
+	"/proc/net/rpc/nfsd.fh/flush",
+	"/proc/net/rpc/nfsd.export/flush",
+	NULL,
+};
+
+/**
+ * Write time into one file
+ *
+ * @param pathname NUL-terminated C string containing POSIX pathname of file to write
+ * @param flushtime NUL-terminated C string containing current time in seconds since the Epoch
+ * @return a FedFsStatus code
+ */
+static FedFsStatus
+junction_write_time(const char *pathname, const char *flushtime)
+{
+	FedFsStatus retval;
+	ssize_t len;
+	int fd;
+
+	fd = open(pathname, O_RDWR);
+	if (fd == -1) {
+		xlog(D_GENERAL, "%s: Failed to open %s: %m",
+			__func__, pathname);
+		/* If the proc files don't exist, no server
+		 * is running on this system */
+		return FEDFS_ERR_NO_CACHE_UPDATE;
+	}
+
+	len = write(fd, flushtime, strlen(flushtime));
+	if (len != (ssize_t)strlen(flushtime)) {
+		xlog(D_GENERAL, "%s: Failed to write %s: %m",
+			__func__, pathname);
+		/* If the proc files exist but the update failed,
+		 * we don't know the state of the cache */
+		retval = FEDFS_ERR_UNKNOWN_CACHE;
+	} else
+		/* Cache flush succeeded */
+		retval = FEDFS_OK;
+
+	(void)close(fd);
+	return retval;
+}
+
+/**
+ * Flush the kernel NFSD's exports cache
+ *
+ * @return a FedFsStatus code
+ */
+FedFsStatus
+junction_flush_exports_cache(void)
+{
+	FedFsStatus retval;
+	char flushtime[20];
+	unsigned int i;
+	time_t now;
+
+	xlog(D_CALL, "%s: Flushing NFSD caches...", __func__);
+
+	now = time(NULL);
+	if (now == -1) {
+		xlog(D_GENERAL, "%s: time(3) failed", __func__);
+		return FEDFS_ERR_SVRFAULT;
+	}
+	snprintf(flushtime, sizeof(flushtime), "%ld\n", now);
+
+	for (i = 0; junction_proc_files[i] != NULL; i++) {
+		retval = junction_write_time(junction_proc_files[i], flushtime);
+		if (retval != FEDFS_OK)
+			return retval;
+	}
+	return FEDFS_OK;
+}