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