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/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/vfs.h>
34 
35 #include <assert.h>
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <libutil.h>
39 #include <signal.h>
40 #include <stdio.h>
41 #include <string.h>
42 #include <unistd.h>
43 #include <libintl.h>
44 
45 #include <libshare.h>
46 #include "libshare_impl.h"
47 #include "nfs.h"
48 
49 #define	_PATH_MOUNTDPID	"/var/run/mountd.pid"
50 #define	OPTSSIZE	1024
51 #define	MAXLINESIZE	(PATH_MAX + OPTSSIZE)
52 #define	ZFS_EXPORTS_FILE	"/etc/zfs/exports"
53 #define	ZFS_EXPORTS_LOCK	ZFS_EXPORTS_FILE".lock"
54 
55 /*
56  * This function translates options to a format acceptable by exports(5), eg.
57  *
58  *	-ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 \
59  *	zfs.freebsd.org 69.147.83.54
60  *
61  * Accepted input formats:
62  *
63  *	ro,network=192.168.0.0,mask=255.255.255.0,maproot=0,zfs.freebsd.org
64  *	ro network=192.168.0.0 mask=255.255.255.0 maproot=0 zfs.freebsd.org
65  *	-ro,-network=192.168.0.0,-mask=255.255.255.0,-maproot=0,zfs.freebsd.org
66  *	-ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 \
67  *	zfs.freebsd.org
68  *
69  * Recognized keywords:
70  *
71  *	ro, maproot, mapall, mask, network, sec, alldirs, public, webnfs,
72  *	index, quiet
73  */
74 static int
75 translate_opts(const char *shareopts, FILE *out)
76 {
77 	static const char *const known_opts[] = { "ro", "maproot", "mapall",
78 	    "mask", "network", "sec", "alldirs", "public", "webnfs", "index",
79 	    "quiet" };
80 	char oldopts[OPTSSIZE], newopts[OPTSSIZE];
81 	char *o, *s = NULL;
82 	unsigned int i;
83 	size_t len;
84 
85 	strlcpy(oldopts, shareopts, sizeof (oldopts));
86 	newopts[0] = '\0';
87 	s = oldopts;
88 	while ((o = strsep(&s, "-, ")) != NULL) {
89 		if (o[0] == '\0')
90 			continue;
91 		for (i = 0; i < ARRAY_SIZE(known_opts); ++i) {
92 			len = strlen(known_opts[i]);
93 			if (strncmp(known_opts[i], o, len) == 0 &&
94 			    (o[len] == '\0' || o[len] == '=')) {
95 				strlcat(newopts, "-", sizeof (newopts));
96 				break;
97 			}
98 		}
99 		strlcat(newopts, o, sizeof (newopts));
100 		strlcat(newopts, " ", sizeof (newopts));
101 	}
102 	return (fputs(newopts, out));
103 }
104 
105 static int
106 nfs_enable_share_impl(sa_share_impl_t impl_share, FILE *tmpfile)
107 {
108 	const char *shareopts = impl_share->sa_shareopts;
109 	if (strcmp(shareopts, "on") == 0)
110 		shareopts = "";
111 
112 	boolean_t need_free;
113 	char *mp;
114 	int rc  = nfs_escape_mountpoint(impl_share->sa_mountpoint, &mp,
115 	    &need_free);
116 	if (rc != SA_OK)
117 		return (rc);
118 
119 	if (fputs(mp, tmpfile) == EOF ||
120 	    fputc('\t', tmpfile) == EOF ||
121 	    translate_opts(shareopts, tmpfile) == EOF ||
122 	    fputc('\n', tmpfile) == EOF) {
123 		fprintf(stderr, "failed to write to temporary file\n");
124 		rc = SA_SYSTEM_ERR;
125 	}
126 
127 	if (need_free)
128 		free(mp);
129 	return (rc);
130 }
131 
132 static int
133 nfs_enable_share(sa_share_impl_t impl_share)
134 {
135 	return (nfs_toggle_share(
136 	    ZFS_EXPORTS_LOCK, ZFS_EXPORTS_FILE, NULL, impl_share,
137 	    nfs_enable_share_impl));
138 }
139 
140 static int
141 nfs_disable_share_impl(sa_share_impl_t impl_share, FILE *tmpfile)
142 {
143 	(void) impl_share, (void) tmpfile;
144 	return (SA_OK);
145 }
146 
147 static int
148 nfs_disable_share(sa_share_impl_t impl_share)
149 {
150 	return (nfs_toggle_share(
151 	    ZFS_EXPORTS_LOCK, ZFS_EXPORTS_FILE, NULL, impl_share,
152 	    nfs_disable_share_impl));
153 }
154 
155 static boolean_t
156 nfs_is_shared(sa_share_impl_t impl_share)
157 {
158 	return (nfs_is_shared_impl(ZFS_EXPORTS_FILE, impl_share));
159 }
160 
161 static int
162 nfs_validate_shareopts(const char *shareopts)
163 {
164 	(void) shareopts;
165 	return (SA_OK);
166 }
167 
168 /*
169  * Commit the shares by restarting mountd.
170  */
171 static int
172 nfs_commit_shares(void)
173 {
174 	struct pidfh *pfh;
175 	pid_t mountdpid;
176 
177 start:
178 	pfh = pidfile_open(_PATH_MOUNTDPID, 0600, &mountdpid);
179 	if (pfh != NULL) {
180 		/* mountd(8) is not running. */
181 		pidfile_remove(pfh);
182 		return (SA_OK);
183 	}
184 	if (errno != EEXIST) {
185 		/* Cannot open pidfile for some reason. */
186 		return (SA_SYSTEM_ERR);
187 	}
188 	if (mountdpid == -1) {
189 		/* mountd(8) exists, but didn't write the PID yet */
190 		usleep(500);
191 		goto start;
192 	}
193 	/* We have mountd(8) PID in mountdpid variable. */
194 	kill(mountdpid, SIGHUP);
195 	return (SA_OK);
196 }
197 
198 static void
199 nfs_truncate_shares(void)
200 {
201 	nfs_reset_shares(ZFS_EXPORTS_LOCK, ZFS_EXPORTS_FILE);
202 }
203 
204 const sa_fstype_t libshare_nfs_type = {
205 	.enable_share = nfs_enable_share,
206 	.disable_share = nfs_disable_share,
207 	.is_shared = nfs_is_shared,
208 
209 	.validate_shareopts = nfs_validate_shareopts,
210 	.commit_shares = nfs_commit_shares,
211 	.truncate_shares = nfs_truncate_shares,
212 };
213