xref: /freebsd-src/sys/contrib/openzfs/lib/libshare/os/freebsd/nfs.c (revision a7148ab39c03abd4d1a84997c70bf96f15dd2a09)
1 /*
2  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * Copyright (c) 2020, 2022 by Delphix. All rights reserved.
27  */
28 
29 #include <sys/param.h>
30 #include <sys/vfs.h>
31 
32 #include <assert.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #include <libutil.h>
36 #include <signal.h>
37 #include <stdio.h>
38 #include <string.h>
39 #include <unistd.h>
40 #include <libintl.h>
41 
42 #include <libshare.h>
43 #include "libshare_impl.h"
44 #include "nfs.h"
45 
46 #define	_PATH_MOUNTDPID	"/var/run/mountd.pid"
47 #define	ZFS_EXPORTS_FILE	"/etc/zfs/exports"
48 #define	ZFS_EXPORTS_LOCK	ZFS_EXPORTS_FILE".lock"
49 
50 /*
51  * This function translates options to a format acceptable by exports(5), eg.
52  *
53  *	-ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 \
54  *	zfs.freebsd.org 69.147.83.54
55  *
56  * Accepted input formats:
57  *
58  *	ro,network=192.168.0.0,mask=255.255.255.0,maproot=0,zfs.freebsd.org
59  *	ro network=192.168.0.0 mask=255.255.255.0 maproot=0 zfs.freebsd.org
60  *	-ro,-network=192.168.0.0,-mask=255.255.255.0,-maproot=0,zfs.freebsd.org
61  *	-ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 \
62  *	zfs.freebsd.org
63  *
64  * Recognized keywords:
65  *
66  *	ro, maproot, mapall, mask, network, sec, alldirs, public, webnfs,
67  *	index, quiet
68  */
69 static int
70 translate_opts(char *oldopts, FILE *out)
71 {
72 	static const char *const known_opts[] = { "ro", "maproot", "mapall",
73 	    "mask", "network", "sec", "alldirs", "public", "webnfs", "index",
74 	    "quiet" };
75 	char *newopts, *o, *s = NULL;
76 	unsigned int i;
77 	size_t len, newopts_len;
78 	int ret;
79 
80 	/*
81 	 * Calculate the length needed for the worst case of a single
82 	 * character option:
83 	 * - Add one to strlen(oldopts) so that the trailing nul is counted
84 	 *   as a separator.
85 	 * - Multiply by 3/2 since the single character option plus separator
86 	 *   is expanded to 3 characters.
87 	 * - Add one for the trailing nul.  Needed for a single repetition of
88 	 *   the single character option and certain other cases.
89 	 */
90 	newopts_len = (strlen(oldopts) + 1) * 3 / 2 + 1;
91 	newopts = malloc(newopts_len);
92 	if (newopts == NULL)
93 		return (EOF);
94 	newopts[0] = '\0';
95 	s = oldopts;
96 	while ((o = strsep(&s, "-, ")) != NULL) {
97 		if (o[0] == '\0')
98 			continue;
99 		for (i = 0; i < ARRAY_SIZE(known_opts); ++i) {
100 			len = strlen(known_opts[i]);
101 			if (strncmp(known_opts[i], o, len) == 0 &&
102 			    (o[len] == '\0' || o[len] == '=')) {
103 				strlcat(newopts, "-", newopts_len);
104 				break;
105 			}
106 		}
107 		strlcat(newopts, o, newopts_len);
108 		strlcat(newopts, " ", newopts_len);
109 	}
110 	ret = fputs(newopts, out);
111 	free(newopts);
112 	return (ret);
113 }
114 
115 static int
116 nfs_enable_share_impl(sa_share_impl_t impl_share, FILE *tmpfile)
117 {
118 	const char *shareopts = impl_share->sa_shareopts;
119 	if (strcmp(shareopts, "on") == 0)
120 		shareopts = "";
121 
122 	boolean_t need_free, fnd_semi;
123 	char *mp, *lineopts, *exportopts, *s;
124 	size_t whitelen;
125 	int rc  = nfs_escape_mountpoint(impl_share->sa_mountpoint, &mp,
126 	    &need_free);
127 	if (rc != SA_OK)
128 		return (rc);
129 
130 	lineopts = strdup(shareopts);
131 	if (lineopts == NULL)
132 		return (SA_SYSTEM_ERR);
133 	s = lineopts;
134 	fnd_semi = B_FALSE;
135 	while ((exportopts = strsep(&s, ";")) != NULL) {
136 		if (s != NULL)
137 			fnd_semi = B_TRUE;
138 		/* Ignore only whitespace between ';' separated option sets. */
139 		if (fnd_semi) {
140 			whitelen = strspn(exportopts, "\t ");
141 			if (exportopts[whitelen] == '\0')
142 				continue;
143 		}
144 		if (fputs(mp, tmpfile) == EOF ||
145 		    fputc('\t', tmpfile) == EOF ||
146 		    translate_opts(exportopts, tmpfile) == EOF ||
147 		    fputc('\n', tmpfile) == EOF) {
148 			fprintf(stderr, "failed to write to temporary file\n");
149 			rc = SA_SYSTEM_ERR;
150 			break;
151 		}
152 	}
153 	free(lineopts);
154 
155 	if (need_free)
156 		free(mp);
157 	return (rc);
158 }
159 
160 static int
161 nfs_enable_share(sa_share_impl_t impl_share)
162 {
163 	return (nfs_toggle_share(
164 	    ZFS_EXPORTS_LOCK, ZFS_EXPORTS_FILE, NULL, impl_share,
165 	    nfs_enable_share_impl));
166 }
167 
168 static int
169 nfs_disable_share_impl(sa_share_impl_t impl_share, FILE *tmpfile)
170 {
171 	(void) impl_share, (void) tmpfile;
172 	return (SA_OK);
173 }
174 
175 static int
176 nfs_disable_share(sa_share_impl_t impl_share)
177 {
178 	return (nfs_toggle_share(
179 	    ZFS_EXPORTS_LOCK, ZFS_EXPORTS_FILE, NULL, impl_share,
180 	    nfs_disable_share_impl));
181 }
182 
183 static boolean_t
184 nfs_is_shared(sa_share_impl_t impl_share)
185 {
186 	return (nfs_is_shared_impl(ZFS_EXPORTS_FILE, impl_share));
187 }
188 
189 static int
190 nfs_validate_shareopts(const char *shareopts)
191 {
192 	if (strlen(shareopts) == 0)
193 		return (SA_SYNTAX_ERR);
194 	return (SA_OK);
195 }
196 
197 /*
198  * Commit the shares by restarting mountd.
199  */
200 static int
201 nfs_commit_shares(void)
202 {
203 	struct pidfh *pfh;
204 	pid_t mountdpid;
205 
206 start:
207 	pfh = pidfile_open(_PATH_MOUNTDPID, 0600, &mountdpid);
208 	if (pfh != NULL) {
209 		/* mountd(8) is not running. */
210 		pidfile_remove(pfh);
211 		return (SA_OK);
212 	}
213 	if (errno != EEXIST) {
214 		/* Cannot open pidfile for some reason. */
215 		return (SA_SYSTEM_ERR);
216 	}
217 	if (mountdpid == -1) {
218 		/* mountd(8) exists, but didn't write the PID yet */
219 		usleep(500);
220 		goto start;
221 	}
222 	/* We have mountd(8) PID in mountdpid variable. */
223 	kill(mountdpid, SIGHUP);
224 	return (SA_OK);
225 }
226 
227 static void
228 nfs_truncate_shares(void)
229 {
230 	nfs_reset_shares(ZFS_EXPORTS_LOCK, ZFS_EXPORTS_FILE);
231 }
232 
233 const sa_fstype_t libshare_nfs_type = {
234 	.enable_share = nfs_enable_share,
235 	.disable_share = nfs_disable_share,
236 	.is_shared = nfs_is_shared,
237 
238 	.validate_shareopts = nfs_validate_shareopts,
239 	.commit_shares = nfs_commit_shares,
240 	.truncate_shares = nfs_truncate_shares,
241 };
242