zfs-builds-mm/zfs-0.8.4/lib/libshare/nfs.c

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2020-07-19 16:21:53 +02:00
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2011 Gunnar Beutner
* Copyright (c) 2012 Cyril Plisko. All rights reserved.
*/
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/wait.h>
#include <unistd.h>
#include <libzfs.h>
#include <libshare.h>
#include "libshare_impl.h"
static boolean_t nfs_available(void);
static sa_fstype_t *nfs_fstype;
/*
* nfs_exportfs_temp_fd refers to a temporary copy of the output
* from exportfs -v.
*/
static int nfs_exportfs_temp_fd = -1;
typedef int (*nfs_shareopt_callback_t)(const char *opt, const char *value,
void *cookie);
typedef int (*nfs_host_callback_t)(const char *sharepath, const char *host,
const char *security, const char *access, void *cookie);
/*
* Invokes the specified callback function for each Solaris share option
* listed in the specified string.
*/
static int
foreach_nfs_shareopt(const char *shareopts,
nfs_shareopt_callback_t callback, void *cookie)
{
char *shareopts_dup, *opt, *cur, *value;
int was_nul, rc;
if (shareopts == NULL)
return (SA_OK);
shareopts_dup = strdup(shareopts);
if (shareopts_dup == NULL)
return (SA_NO_MEMORY);
opt = shareopts_dup;
was_nul = 0;
while (1) {
cur = opt;
while (*cur != ',' && *cur != '\0')
cur++;
if (*cur == '\0')
was_nul = 1;
*cur = '\0';
if (cur > opt) {
value = strchr(opt, '=');
if (value != NULL) {
*value = '\0';
value++;
}
rc = callback(opt, value, cookie);
if (rc != SA_OK) {
free(shareopts_dup);
return (rc);
}
}
opt = cur + 1;
if (was_nul)
break;
}
free(shareopts_dup);
return (0);
}
typedef struct nfs_host_cookie_s {
nfs_host_callback_t callback;
const char *sharepath;
void *cookie;
const char *security;
} nfs_host_cookie_t;
/*
* Helper function for foreach_nfs_host. This function checks whether the
* current share option is a host specification and invokes a callback
* function with information about the host.
*/
static int
foreach_nfs_host_cb(const char *opt, const char *value, void *pcookie)
{
int rc;
const char *access;
char *host_dup, *host, *next;
nfs_host_cookie_t *udata = (nfs_host_cookie_t *)pcookie;
#ifdef DEBUG
fprintf(stderr, "foreach_nfs_host_cb: key=%s, value=%s\n", opt, value);
#endif
if (strcmp(opt, "sec") == 0)
udata->security = value;
if (strcmp(opt, "rw") == 0 || strcmp(opt, "ro") == 0) {
if (value == NULL)
value = "*";
access = opt;
host_dup = strdup(value);
if (host_dup == NULL)
return (SA_NO_MEMORY);
host = host_dup;
do {
next = strchr(host, ':');
if (next != NULL) {
*next = '\0';
next++;
}
rc = udata->callback(udata->sharepath, host,
udata->security, access, udata->cookie);
if (rc != SA_OK) {
free(host_dup);
return (rc);
}
host = next;
} while (host != NULL);
free(host_dup);
}
return (SA_OK);
}
/*
* Invokes a callback function for all NFS hosts that are set for a share.
*/
static int
foreach_nfs_host(sa_share_impl_t impl_share, nfs_host_callback_t callback,
void *cookie)
{
nfs_host_cookie_t udata;
char *shareopts;
udata.callback = callback;
udata.sharepath = impl_share->sharepath;
udata.cookie = cookie;
udata.security = "sys";
shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
return foreach_nfs_shareopt(shareopts, foreach_nfs_host_cb,
&udata);
}
/*
* Converts a Solaris NFS host specification to its Linux equivalent.
*/
static int
get_linux_hostspec(const char *solaris_hostspec, char **plinux_hostspec)
{
/*
* For now we just support CIDR masks (e.g. @192.168.0.0/16) and host
* wildcards (e.g. *.example.org).
*/
if (solaris_hostspec[0] == '@') {
/*
* Solaris host specifier, e.g. @192.168.0.0/16; we just need
* to skip the @ in this case
*/
*plinux_hostspec = strdup(solaris_hostspec + 1);
} else {
*plinux_hostspec = strdup(solaris_hostspec);
}
if (*plinux_hostspec == NULL) {
return (SA_NO_MEMORY);
}
return (SA_OK);
}
/*
* Used internally by nfs_enable_share to enable sharing for a single host.
*/
static int
nfs_enable_share_one(const char *sharepath, const char *host,
const char *security, const char *access, void *pcookie)
{
int rc;
char *linuxhost, *hostpath, *opts;
const char *linux_opts = (const char *)pcookie;
char *argv[6];
/* exportfs -i -o sec=XX,rX,<opts> <host>:<sharepath> */
rc = get_linux_hostspec(host, &linuxhost);
if (rc < 0)
exit(1);
hostpath = malloc(strlen(linuxhost) + 1 + strlen(sharepath) + 1);
if (hostpath == NULL) {
free(linuxhost);
exit(1);
}
sprintf(hostpath, "%s:%s", linuxhost, sharepath);
free(linuxhost);
if (linux_opts == NULL)
linux_opts = "";
opts = malloc(4 + strlen(security) + 4 + strlen(linux_opts) + 1);
if (opts == NULL)
exit(1);
sprintf(opts, "sec=%s,%s,%s", security, access, linux_opts);
#ifdef DEBUG
fprintf(stderr, "sharing %s with opts %s\n", hostpath, opts);
#endif
argv[0] = "/usr/sbin/exportfs";
argv[1] = "-i";
argv[2] = "-o";
argv[3] = opts;
argv[4] = hostpath;
argv[5] = NULL;
rc = libzfs_run_process(argv[0], argv, 0);
free(hostpath);
free(opts);
if (rc < 0)
return (SA_SYSTEM_ERR);
else
return (SA_OK);
}
/*
* Adds a Linux share option to an array of NFS options.
*/
static int
add_linux_shareopt(char **plinux_opts, const char *key, const char *value)
{
size_t len = 0;
char *new_linux_opts;
if (*plinux_opts != NULL)
len = strlen(*plinux_opts);
new_linux_opts = realloc(*plinux_opts, len + 1 + strlen(key) +
(value ? 1 + strlen(value) : 0) + 1);
if (new_linux_opts == NULL)
return (SA_NO_MEMORY);
new_linux_opts[len] = '\0';
if (len > 0)
strcat(new_linux_opts, ",");
strcat(new_linux_opts, key);
if (value != NULL) {
strcat(new_linux_opts, "=");
strcat(new_linux_opts, value);
}
*plinux_opts = new_linux_opts;
return (SA_OK);
}
/*
* Validates and converts a single Solaris share option to its Linux
* equivalent.
*/
static int
get_linux_shareopts_cb(const char *key, const char *value, void *cookie)
{
char **plinux_opts = (char **)cookie;
/* host-specific options, these are taken care of elsewhere */
if (strcmp(key, "ro") == 0 || strcmp(key, "rw") == 0 ||
strcmp(key, "sec") == 0)
return (SA_OK);
if (strcmp(key, "anon") == 0)
key = "anonuid";
if (strcmp(key, "root_mapping") == 0) {
(void) add_linux_shareopt(plinux_opts, "root_squash", NULL);
key = "anonuid";
}
if (strcmp(key, "nosub") == 0)
key = "subtree_check";
if (strcmp(key, "insecure") != 0 && strcmp(key, "secure") != 0 &&
strcmp(key, "async") != 0 && strcmp(key, "sync") != 0 &&
strcmp(key, "no_wdelay") != 0 && strcmp(key, "wdelay") != 0 &&
strcmp(key, "nohide") != 0 && strcmp(key, "hide") != 0 &&
strcmp(key, "crossmnt") != 0 &&
strcmp(key, "no_subtree_check") != 0 &&
strcmp(key, "subtree_check") != 0 &&
strcmp(key, "insecure_locks") != 0 &&
strcmp(key, "secure_locks") != 0 &&
strcmp(key, "no_auth_nlm") != 0 && strcmp(key, "auth_nlm") != 0 &&
strcmp(key, "no_acl") != 0 && strcmp(key, "mountpoint") != 0 &&
strcmp(key, "mp") != 0 && strcmp(key, "fsuid") != 0 &&
strcmp(key, "refer") != 0 && strcmp(key, "replicas") != 0 &&
strcmp(key, "root_squash") != 0 &&
strcmp(key, "no_root_squash") != 0 &&
strcmp(key, "all_squash") != 0 &&
strcmp(key, "no_all_squash") != 0 && strcmp(key, "fsid") != 0 &&
strcmp(key, "anonuid") != 0 && strcmp(key, "anongid") != 0) {
return (SA_SYNTAX_ERR);
}
(void) add_linux_shareopt(plinux_opts, key, value);
return (SA_OK);
}
/*
* Takes a string containing Solaris share options (e.g. "sync,no_acl") and
* converts them to a NULL-terminated array of Linux NFS options.
*/
static int
get_linux_shareopts(const char *shareopts, char **plinux_opts)
{
int rc;
assert(plinux_opts != NULL);
*plinux_opts = NULL;
/* no_subtree_check - Default as of nfs-utils v1.1.0 */
(void) add_linux_shareopt(plinux_opts, "no_subtree_check", NULL);
/* mountpoint - Restrict exports to ZFS mountpoints */
(void) add_linux_shareopt(plinux_opts, "mountpoint", NULL);
rc = foreach_nfs_shareopt(shareopts, get_linux_shareopts_cb,
plinux_opts);
if (rc != SA_OK) {
free(*plinux_opts);
*plinux_opts = NULL;
}
return (rc);
}
/*
* Enables NFS sharing for the specified share.
*/
static int
nfs_enable_share(sa_share_impl_t impl_share)
{
char *shareopts, *linux_opts;
int rc;
if (!nfs_available()) {
return (SA_SYSTEM_ERR);
}
shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
if (shareopts == NULL)
return (SA_OK);
rc = get_linux_shareopts(shareopts, &linux_opts);
if (rc != SA_OK)
return (rc);
rc = foreach_nfs_host(impl_share, nfs_enable_share_one, linux_opts);
free(linux_opts);
return (rc);
}
/*
* Used internally by nfs_disable_share to disable sharing for a single host.
*/
static int
nfs_disable_share_one(const char *sharepath, const char *host,
const char *security, const char *access, void *cookie)
{
int rc;
char *linuxhost, *hostpath;
char *argv[4];
rc = get_linux_hostspec(host, &linuxhost);
if (rc < 0)
exit(1);
hostpath = malloc(strlen(linuxhost) + 1 + strlen(sharepath) + 1);
if (hostpath == NULL) {
free(linuxhost);
exit(1);
}
sprintf(hostpath, "%s:%s", linuxhost, sharepath);
free(linuxhost);
#ifdef DEBUG
fprintf(stderr, "unsharing %s\n", hostpath);
#endif
argv[0] = "/usr/sbin/exportfs";
argv[1] = "-u";
argv[2] = hostpath;
argv[3] = NULL;
rc = libzfs_run_process(argv[0], argv, 0);
free(hostpath);
if (rc < 0)
return (SA_SYSTEM_ERR);
else
return (SA_OK);
}
/*
* Disables NFS sharing for the specified share.
*/
static int
nfs_disable_share(sa_share_impl_t impl_share)
{
if (!nfs_available()) {
/*
* The share can't possibly be active, so nothing
* needs to be done to disable it.
*/
return (SA_OK);
}
return (foreach_nfs_host(impl_share, nfs_disable_share_one, NULL));
}
/*
* Checks whether the specified NFS share options are syntactically correct.
*/
static int
nfs_validate_shareopts(const char *shareopts)
{
char *linux_opts;
int rc;
rc = get_linux_shareopts(shareopts, &linux_opts);
if (rc != SA_OK)
return (rc);
free(linux_opts);
return (SA_OK);
}
/*
* Checks whether a share is currently active.
*/
static boolean_t
nfs_is_share_active(sa_share_impl_t impl_share)
{
int fd;
char line[512];
char *tab, *cur;
FILE *nfs_exportfs_temp_fp;
if (!nfs_available())
return (B_FALSE);
if ((fd = dup(nfs_exportfs_temp_fd)) == -1)
return (B_FALSE);
nfs_exportfs_temp_fp = fdopen(fd, "r");
if (nfs_exportfs_temp_fp == NULL)
return (B_FALSE);
if (fseek(nfs_exportfs_temp_fp, 0, SEEK_SET) < 0) {
fclose(nfs_exportfs_temp_fp);
return (B_FALSE);
}
while (fgets(line, sizeof (line), nfs_exportfs_temp_fp) != NULL) {
/*
* exportfs uses separate lines for the share path
* and the export options when the share path is longer
* than a certain amount of characters; this ignores
* the option lines
*/
if (line[0] == '\t')
continue;
tab = strchr(line, '\t');
if (tab != NULL) {
*tab = '\0';
cur = tab - 1;
} else {
/*
* there's no tab character, which means the
* NFS options are on a separate line; we just
* need to remove the new-line character
* at the end of the line
*/
cur = line + strlen(line) - 1;
}
/* remove trailing spaces and new-line characters */
while (cur >= line && (*cur == ' ' || *cur == '\n'))
*cur-- = '\0';
if (strcmp(line, impl_share->sharepath) == 0) {
fclose(nfs_exportfs_temp_fp);
return (B_TRUE);
}
}
fclose(nfs_exportfs_temp_fp);
return (B_FALSE);
}
/*
* Called to update a share's options. A share's options might be out of
* date if the share was loaded from disk (i.e. /etc/dfs/sharetab) and the
* "sharenfs" dataset property has changed in the meantime. This function
* also takes care of re-enabling the share if necessary.
*/
static int
nfs_update_shareopts(sa_share_impl_t impl_share, const char *resource,
const char *shareopts)
{
char *shareopts_dup;
boolean_t needs_reshare = B_FALSE;
char *old_shareopts;
FSINFO(impl_share, nfs_fstype)->active =
nfs_is_share_active(impl_share);
old_shareopts = FSINFO(impl_share, nfs_fstype)->shareopts;
if (strcmp(shareopts, "on") == 0)
shareopts = "rw,crossmnt";
if (FSINFO(impl_share, nfs_fstype)->active && old_shareopts != NULL &&
strcmp(old_shareopts, shareopts) != 0) {
needs_reshare = B_TRUE;
nfs_disable_share(impl_share);
}
shareopts_dup = strdup(shareopts);
if (shareopts_dup == NULL)
return (SA_NO_MEMORY);
if (old_shareopts != NULL)
free(old_shareopts);
FSINFO(impl_share, nfs_fstype)->shareopts = shareopts_dup;
if (needs_reshare)
nfs_enable_share(impl_share);
return (SA_OK);
}
/*
* Clears a share's NFS options. Used by libshare to
* clean up shares that are about to be free()'d.
*/
static void
nfs_clear_shareopts(sa_share_impl_t impl_share)
{
free(FSINFO(impl_share, nfs_fstype)->shareopts);
FSINFO(impl_share, nfs_fstype)->shareopts = NULL;
}
static const sa_share_ops_t nfs_shareops = {
.enable_share = nfs_enable_share,
.disable_share = nfs_disable_share,
.validate_shareopts = nfs_validate_shareopts,
.update_shareopts = nfs_update_shareopts,
.clear_shareopts = nfs_clear_shareopts,
};
/*
* nfs_check_exportfs() checks that the exportfs command runs
* and also maintains a temporary copy of the output from
* exportfs -v.
* To update this temporary copy simply call this function again.
*
* TODO : Use /var/lib/nfs/etab instead of our private copy.
* But must implement locking to prevent concurrent access.
*
* TODO : The temporary file descriptor is never closed since
* there is no libshare_nfs_fini() function.
*/
static int
nfs_check_exportfs(void)
{
pid_t pid;
int rc, status;
static char nfs_exportfs_tempfile[] = "/tmp/exportfs.XXXXXX";
/*
* Close any existing temporary copies of output from exportfs.
* We have already called unlink() so file will be deleted.
*/
if (nfs_exportfs_temp_fd >= 0)
close(nfs_exportfs_temp_fd);
nfs_exportfs_temp_fd = mkstemp(nfs_exportfs_tempfile);
if (nfs_exportfs_temp_fd < 0)
return (SA_SYSTEM_ERR);
unlink(nfs_exportfs_tempfile);
(void) fcntl(nfs_exportfs_temp_fd, F_SETFD, FD_CLOEXEC);
pid = fork();
if (pid < 0) {
(void) close(nfs_exportfs_temp_fd);
nfs_exportfs_temp_fd = -1;
return (SA_SYSTEM_ERR);
}
if (pid > 0) {
while ((rc = waitpid(pid, &status, 0)) <= 0 &&
errno == EINTR) { }
if (rc <= 0) {
(void) close(nfs_exportfs_temp_fd);
nfs_exportfs_temp_fd = -1;
return (SA_SYSTEM_ERR);
}
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
(void) close(nfs_exportfs_temp_fd);
nfs_exportfs_temp_fd = -1;
return (SA_CONFIG_ERR);
}
return (SA_OK);
}
/* child */
/* exportfs -v */
if (dup2(nfs_exportfs_temp_fd, STDOUT_FILENO) < 0)
exit(1);
rc = execlp("/usr/sbin/exportfs", "exportfs", "-v", NULL);
if (rc < 0) {
exit(1);
}
exit(0);
}
/*
* Provides a convenient wrapper for determining nfs availability
*/
static boolean_t
nfs_available(void)
{
if (nfs_exportfs_temp_fd == -1)
(void) nfs_check_exportfs();
return ((nfs_exportfs_temp_fd != -1) ? B_TRUE : B_FALSE);
}
/*
* Initializes the NFS functionality of libshare.
*/
void
libshare_nfs_init(void)
{
nfs_fstype = register_fstype("nfs", &nfs_shareops);
}