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/**
* @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;
}
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