1 /* $NetBSD: fsshare.c,v 1.4 2019/01/27 02:08:34 pgoyette Exp $ */
2
3 /*-
4 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 /* __FBSDID("$FreeBSD: head/cddl/compat/opensolaris/misc/fsshare.c 299342 2016-05-10 07:50:57Z bapt $"); */
31
32 __RCSID("$NetBSD: fsshare.c,v 1.4 2019/01/27 02:08:34 pgoyette Exp $");
33
34 #include <sys/param.h>
35
36 #include <assert.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <fsshare.h>
40 #include <pathnames.h> /* _PATH_MOUNTDPID */
41 #include <signal.h>
42 #include <stdio.h>
43 #include <string.h>
44 #include <unistd.h>
45 #include <stdlib.h>
46
47 #define FILE_HEADER "# !!! DO NOT EDIT THIS FILE MANUALLY !!!\n\n"
48 #define OPTSSIZE 1024
49 #define MAXLINESIZE (PATH_MAX + OPTSSIZE)
50
51 static void
restart_mountd(void)52 restart_mountd(void)
53 {
54 int pid;
55 FILE *pfh;
56
57 pfh = fopen(_PATH_MOUNTDPID, "r");
58 if (pfh == NULL)
59 return;
60 fscanf(pfh, "%d", &pid);
61 fclose(pfh);
62 kill((pid_t)pid, SIGHUP);
63 }
64
65 /*
66 * Read one line from a file. Skip comments, empty lines and a line with a
67 * mountpoint specified in the 'skip' argument.
68 */
69 static char *
zgetline(FILE * fd,const char * skip)70 zgetline(FILE *fd, const char *skip)
71 {
72 static char line[MAXLINESIZE];
73 size_t len, skiplen;
74 char *s, last;
75
76 if (skip != NULL)
77 skiplen = strlen(skip);
78 for (;;) {
79 s = fgets(line, sizeof(line), fd);
80 if (s == NULL)
81 return (NULL);
82 /* Skip empty lines and comments. */
83 if (line[0] == '\n' || line[0] == '#')
84 continue;
85 len = strlen(line);
86 if (line[len - 1] == '\n')
87 line[len - 1] = '\0';
88 last = line[skiplen];
89 /* Skip the given mountpoint. */
90 if (skip != NULL && strncmp(skip, line, skiplen) == 0 &&
91 (last == '\t' || last == ' ' || last == '\0')) {
92 continue;
93 }
94 break;
95 }
96 return (line);
97 }
98
99 /*
100 * Function translate options to a format acceptable by exports(5), eg.
101 *
102 * -ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 freefall.freebsd.org 69.147.83.54
103 *
104 * Accepted input formats:
105 *
106 * ro,network=192.168.0.0,mask=255.255.255.0,maproot=0,freefall.freebsd.org
107 * ro network=192.168.0.0 mask=255.255.255.0 maproot=0 freefall.freebsd.org
108 * -ro,-network=192.168.0.0,-mask=255.255.255.0,-maproot=0,freefall.freebsd.org
109 * -ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 freefall.freebsd.org
110 *
111 * Recognized keywords:
112 *
113 * ro, maproot, mapall, mask, network, alldirs, public, webnfs, index, quiet
114 *
115 */
116 static const char *known_opts[] = { "ro", "maproot", "mapall", "mask",
117 "network", "alldirs", "public", "webnfs", "index", "quiet", NULL };
118 static char *
translate_opts(const char * shareopts)119 translate_opts(const char *shareopts)
120 {
121 static char newopts[OPTSSIZE];
122 char oldopts[OPTSSIZE];
123 char *o, *s = NULL;
124 unsigned int i;
125 size_t len;
126
127 strlcpy(oldopts, shareopts, sizeof(oldopts));
128 newopts[0] = '\0';
129 s = oldopts;
130 while ((o = strsep(&s, "-, ")) != NULL) {
131 if (o[0] == '\0')
132 continue;
133 for (i = 0; known_opts[i] != NULL; i++) {
134 len = strlen(known_opts[i]);
135 if (strncmp(known_opts[i], o, len) == 0 &&
136 (o[len] == '\0' || o[len] == '=')) {
137 strlcat(newopts, "-", sizeof(newopts));
138 break;
139 }
140 }
141 strlcat(newopts, o, sizeof(newopts));
142 strlcat(newopts, " ", sizeof(newopts));
143 }
144 return (newopts);
145 }
146
147 static int
fsshare_main(const char * file,const char * mountpoint,const char * shareopts,int share)148 fsshare_main(const char *file, const char *mountpoint, const char *shareopts,
149 int share)
150 {
151 char tmpfile[PATH_MAX];
152 char *line;
153 FILE *newfd, *oldfd;
154 int fd, error;
155
156 newfd = oldfd = NULL;
157 error = 0;
158
159 /*
160 * Create temporary file in the same directory, so we can atomically
161 * rename it.
162 */
163 if (strlcpy(tmpfile, file, sizeof(tmpfile)) >= sizeof(tmpfile))
164 return (ENAMETOOLONG);
165 if (strlcat(tmpfile, ".XXXXXXXX", sizeof(tmpfile)) >= sizeof(tmpfile))
166 return (ENAMETOOLONG);
167 fd = mkstemp(tmpfile);
168 if (fd == -1)
169 return (errno);
170 /*
171 * File name is random, so we don't really need file lock now, but it
172 * will be needed after rename(2).
173 */
174 error = flock(fd, LOCK_EX);
175 assert(error == 0 || (error == -1 && errno == EOPNOTSUPP));
176 newfd = fdopen(fd, "r+");
177 assert(newfd != NULL);
178 /* Open old exports file. */
179 oldfd = fopen(file, "r");
180 if (oldfd == NULL) {
181 if (share) {
182 if (errno != ENOENT) {
183 error = errno;
184 goto out;
185 }
186 } else {
187 /* If there is no exports file, ignore the error. */
188 if (errno == ENOENT)
189 errno = 0;
190 error = errno;
191 goto out;
192 }
193 } else {
194 error = flock(fileno(oldfd), LOCK_EX);
195 assert(error == 0 || (error == -1 && errno == EOPNOTSUPP));
196 error = 0;
197 }
198
199 /* Place big, fat warning at the begining of the file. */
200 fprintf(newfd, "%s", FILE_HEADER);
201 while (oldfd != NULL && (line = zgetline(oldfd, mountpoint)) != NULL)
202 fprintf(newfd, "%s\n", line);
203 if (oldfd != NULL && ferror(oldfd) != 0) {
204 error = ferror(oldfd);
205 goto out;
206 }
207 if (ferror(newfd) != 0) {
208 error = ferror(newfd);
209 goto out;
210 }
211 if (share) {
212 fprintf(newfd, "%s\t%s\n", mountpoint,
213 translate_opts(shareopts));
214 }
215
216 out:
217 if (error != 0)
218 unlink(tmpfile);
219 else {
220 if (rename(tmpfile, file) == -1) {
221 error = errno;
222 unlink(tmpfile);
223 } else {
224 /*
225 * Send SIGHUP to mountd, but unlock exports file later.
226 */
227 restart_mountd();
228 }
229 }
230 if (oldfd != NULL) {
231 flock(fileno(oldfd), LOCK_UN);
232 fclose(oldfd);
233 }
234 if (newfd != NULL) {
235 flock(fileno(newfd), LOCK_UN);
236 fclose(newfd);
237 }
238 return (error);
239 }
240
241 /*
242 * Add the given mountpoint to the given exports file.
243 */
244 int
fsshare(const char * file,const char * mountpoint,const char * shareopts)245 fsshare(const char *file, const char *mountpoint, const char *shareopts)
246 {
247
248 return (fsshare_main(file, mountpoint, shareopts, 1));
249 }
250
251 /*
252 * Remove the given mountpoint from the given exports file.
253 */
254 int
fsunshare(const char * file,const char * mountpoint)255 fsunshare(const char *file, const char *mountpoint)
256 {
257
258 return (fsshare_main(file, mountpoint, NULL, 0));
259 }
260