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 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 "libzfs_impl.h" 46 #include "libshare_impl.h" 47 #include "nfs.h" 48 49 #define _PATH_MOUNTDPID "/var/run/mountd.pid" 50 #define FILE_HEADER "# !!! DO NOT EDIT THIS FILE MANUALLY !!!\n\n" 51 #define OPTSSIZE 1024 52 #define MAXLINESIZE (PATH_MAX + OPTSSIZE) 53 #define ZFS_EXPORTS_FILE "/etc/zfs/exports" 54 #define ZFS_EXPORTS_LOCK ZFS_EXPORTS_FILE".lock" 55 56 static sa_fstype_t *nfs_fstype; 57 58 static int nfs_lock_fd = -1; 59 60 /* 61 * The nfs_exports_[lock|unlock] is used to guard against conconcurrent 62 * updates to the exports file. Each protocol is responsible for 63 * providing the necessary locking to ensure consistency. 64 */ 65 static int 66 nfs_exports_lock(void) 67 { 68 nfs_lock_fd = open(ZFS_EXPORTS_LOCK, 69 O_RDWR | O_CREAT, 0600); 70 if (nfs_lock_fd == -1) { 71 fprintf(stderr, "failed to lock %s: %s\n", 72 ZFS_EXPORTS_LOCK, strerror(errno)); 73 return (errno); 74 } 75 if (flock(nfs_lock_fd, LOCK_EX) != 0) { 76 fprintf(stderr, "failed to lock %s: %s\n", 77 ZFS_EXPORTS_LOCK, strerror(errno)); 78 return (errno); 79 } 80 return (0); 81 } 82 83 static void 84 nfs_exports_unlock(void) 85 { 86 verify(nfs_lock_fd > 0); 87 88 if (flock(nfs_lock_fd, LOCK_UN) != 0) { 89 fprintf(stderr, "failed to unlock %s: %s\n", 90 ZFS_EXPORTS_LOCK, strerror(errno)); 91 } 92 close(nfs_lock_fd); 93 nfs_lock_fd = -1; 94 } 95 96 /* 97 * Read one line from a file. Skip comments, empty lines and a line with a 98 * mountpoint specified in the 'skip' argument. 99 * 100 * NOTE: This function returns a static buffer and thus is not thread-safe. 101 */ 102 static char * 103 zgetline(FILE *fd, const char *skip) 104 { 105 static char line[MAXLINESIZE]; 106 size_t len, skiplen = 0; 107 char *s, last; 108 109 if (skip != NULL) 110 skiplen = strlen(skip); 111 for (;;) { 112 s = fgets(line, sizeof (line), fd); 113 if (s == NULL) 114 return (NULL); 115 /* Skip empty lines and comments. */ 116 if (line[0] == '\n' || line[0] == '#') 117 continue; 118 len = strlen(line); 119 if (line[len - 1] == '\n') 120 line[len - 1] = '\0'; 121 last = line[skiplen]; 122 /* Skip the given mountpoint. */ 123 if (skip != NULL && strncmp(skip, line, skiplen) == 0 && 124 (last == '\t' || last == ' ' || last == '\0')) { 125 continue; 126 } 127 break; 128 } 129 return (line); 130 } 131 132 /* 133 * This function translate options to a format acceptable by exports(5), eg. 134 * 135 * -ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 \ 136 * zfs.freebsd.org 69.147.83.54 137 * 138 * Accepted input formats: 139 * 140 * ro,network=192.168.0.0,mask=255.255.255.0,maproot=0,zfs.freebsd.org 141 * ro network=192.168.0.0 mask=255.255.255.0 maproot=0 zfs.freebsd.org 142 * -ro,-network=192.168.0.0,-mask=255.255.255.0,-maproot=0,zfs.freebsd.org 143 * -ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 \ 144 * zfs.freebsd.org 145 * 146 * Recognized keywords: 147 * 148 * ro, maproot, mapall, mask, network, sec, alldirs, public, webnfs, 149 * index, quiet 150 * 151 * NOTE: This function returns a static buffer and thus is not thread-safe. 152 */ 153 static char * 154 translate_opts(const char *shareopts) 155 { 156 static const char *known_opts[] = { "ro", "maproot", "mapall", "mask", 157 "network", "sec", "alldirs", "public", "webnfs", "index", "quiet", 158 NULL }; 159 static char newopts[OPTSSIZE]; 160 char oldopts[OPTSSIZE]; 161 char *o, *s = NULL; 162 unsigned int i; 163 size_t len; 164 165 strlcpy(oldopts, shareopts, sizeof (oldopts)); 166 newopts[0] = '\0'; 167 s = oldopts; 168 while ((o = strsep(&s, "-, ")) != NULL) { 169 if (o[0] == '\0') 170 continue; 171 for (i = 0; known_opts[i] != NULL; i++) { 172 len = strlen(known_opts[i]); 173 if (strncmp(known_opts[i], o, len) == 0 && 174 (o[len] == '\0' || o[len] == '=')) { 175 strlcat(newopts, "-", sizeof (newopts)); 176 break; 177 } 178 } 179 strlcat(newopts, o, sizeof (newopts)); 180 strlcat(newopts, " ", sizeof (newopts)); 181 } 182 return (newopts); 183 } 184 185 static char * 186 nfs_init_tmpfile(void) 187 { 188 char *tmpfile = NULL; 189 190 if (asprintf(&tmpfile, "%s%s", ZFS_EXPORTS_FILE, ".XXXXXXXX") == -1) { 191 fprintf(stderr, "Unable to allocate buffer for temporary " 192 "file name\n"); 193 return (NULL); 194 } 195 196 int fd = mkstemp(tmpfile); 197 if (fd == -1) { 198 fprintf(stderr, "Unable to create temporary file: %s", 199 strerror(errno)); 200 free(tmpfile); 201 return (NULL); 202 } 203 close(fd); 204 return (tmpfile); 205 } 206 207 static int 208 nfs_fini_tmpfile(char *tmpfile) 209 { 210 if (rename(tmpfile, ZFS_EXPORTS_FILE) == -1) { 211 fprintf(stderr, "Unable to rename %s: %s\n", tmpfile, 212 strerror(errno)); 213 unlink(tmpfile); 214 free(tmpfile); 215 return (SA_SYSTEM_ERR); 216 } 217 free(tmpfile); 218 return (SA_OK); 219 } 220 221 /* 222 * This function copies all entries from the exports file to "filename", 223 * omitting any entries for the specified mountpoint. 224 */ 225 static int 226 nfs_copy_entries(char *filename, const char *mountpoint) 227 { 228 int error = SA_OK; 229 char *line; 230 231 /* 232 * If the file doesn't exist then there is nothing more 233 * we need to do. 234 */ 235 FILE *oldfp = fopen(ZFS_EXPORTS_FILE, "r"); 236 if (oldfp == NULL) 237 return (SA_OK); 238 239 FILE *newfp = fopen(filename, "w+"); 240 fputs(FILE_HEADER, newfp); 241 while ((line = zgetline(oldfp, mountpoint)) != NULL) 242 fprintf(newfp, "%s\n", line); 243 if (ferror(oldfp) != 0) { 244 error = ferror(oldfp); 245 } 246 if (error == 0 && ferror(newfp) != 0) { 247 error = ferror(newfp); 248 } 249 250 if (fclose(newfp) != 0) { 251 fprintf(stderr, "Unable to close file %s: %s\n", 252 filename, strerror(errno)); 253 error = error != 0 ? error : SA_SYSTEM_ERR; 254 } 255 fclose(oldfp); 256 257 return (error); 258 } 259 260 static int 261 nfs_enable_share(sa_share_impl_t impl_share) 262 { 263 char *filename = NULL; 264 int error; 265 266 if ((filename = nfs_init_tmpfile()) == NULL) 267 return (SA_SYSTEM_ERR); 268 269 error = nfs_exports_lock(); 270 if (error != 0) { 271 unlink(filename); 272 free(filename); 273 return (error); 274 } 275 276 error = nfs_copy_entries(filename, impl_share->sa_mountpoint); 277 if (error != SA_OK) { 278 unlink(filename); 279 free(filename); 280 nfs_exports_unlock(); 281 return (error); 282 } 283 284 FILE *fp = fopen(filename, "a+"); 285 if (fp == NULL) { 286 fprintf(stderr, "failed to open %s file: %s", filename, 287 strerror(errno)); 288 unlink(filename); 289 free(filename); 290 nfs_exports_unlock(); 291 return (SA_SYSTEM_ERR); 292 } 293 char *shareopts = FSINFO(impl_share, nfs_fstype)->shareopts; 294 if (strcmp(shareopts, "on") == 0) 295 shareopts = ""; 296 297 if (fprintf(fp, "%s\t%s\n", impl_share->sa_mountpoint, 298 translate_opts(shareopts)) < 0) { 299 fprintf(stderr, "failed to write to %s\n", filename); 300 fclose(fp); 301 unlink(filename); 302 free(filename); 303 nfs_exports_unlock(); 304 return (SA_SYSTEM_ERR); 305 } 306 307 if (fclose(fp) != 0) { 308 fprintf(stderr, "Unable to close file %s: %s\n", 309 filename, strerror(errno)); 310 unlink(filename); 311 free(filename); 312 nfs_exports_unlock(); 313 return (SA_SYSTEM_ERR); 314 } 315 error = nfs_fini_tmpfile(filename); 316 nfs_exports_unlock(); 317 return (error); 318 } 319 320 static int 321 nfs_disable_share(sa_share_impl_t impl_share) 322 { 323 int error; 324 char *filename = NULL; 325 326 if ((filename = nfs_init_tmpfile()) == NULL) 327 return (SA_SYSTEM_ERR); 328 329 error = nfs_exports_lock(); 330 if (error != 0) { 331 unlink(filename); 332 free(filename); 333 return (error); 334 } 335 336 error = nfs_copy_entries(filename, impl_share->sa_mountpoint); 337 if (error != SA_OK) { 338 unlink(filename); 339 free(filename); 340 nfs_exports_unlock(); 341 return (error); 342 } 343 344 error = nfs_fini_tmpfile(filename); 345 nfs_exports_unlock(); 346 return (error); 347 } 348 349 /* 350 * NOTE: This function returns a static buffer and thus is not thread-safe. 351 */ 352 static boolean_t 353 nfs_is_shared(sa_share_impl_t impl_share) 354 { 355 static char line[MAXLINESIZE]; 356 char *s, last; 357 size_t len; 358 char *mntpoint = impl_share->sa_mountpoint; 359 size_t mntlen = strlen(mntpoint); 360 361 FILE *fp = fopen(ZFS_EXPORTS_FILE, "r"); 362 if (fp == NULL) 363 return (B_FALSE); 364 365 for (;;) { 366 s = fgets(line, sizeof (line), fp); 367 if (s == NULL) 368 return (B_FALSE); 369 /* Skip empty lines and comments. */ 370 if (line[0] == '\n' || line[0] == '#') 371 continue; 372 len = strlen(line); 373 if (line[len - 1] == '\n') 374 line[len - 1] = '\0'; 375 last = line[mntlen]; 376 /* Skip the given mountpoint. */ 377 if (strncmp(mntpoint, line, mntlen) == 0 && 378 (last == '\t' || last == ' ' || last == '\0')) { 379 fclose(fp); 380 return (B_TRUE); 381 } 382 } 383 fclose(fp); 384 return (B_FALSE); 385 } 386 387 static int 388 nfs_validate_shareopts(const char *shareopts) 389 { 390 return (SA_OK); 391 } 392 393 static int 394 nfs_update_shareopts(sa_share_impl_t impl_share, const char *shareopts) 395 { 396 FSINFO(impl_share, nfs_fstype)->shareopts = (char *)shareopts; 397 return (SA_OK); 398 } 399 400 static void 401 nfs_clear_shareopts(sa_share_impl_t impl_share) 402 { 403 FSINFO(impl_share, nfs_fstype)->shareopts = NULL; 404 } 405 406 /* 407 * Commit the shares by restarting mountd. 408 */ 409 static int 410 nfs_commit_shares(void) 411 { 412 struct pidfh *pfh; 413 pid_t mountdpid; 414 415 pfh = pidfile_open(_PATH_MOUNTDPID, 0600, &mountdpid); 416 if (pfh != NULL) { 417 /* Mountd is not running. */ 418 pidfile_remove(pfh); 419 return (SA_OK); 420 } 421 if (errno != EEXIST) { 422 /* Cannot open pidfile for some reason. */ 423 return (SA_SYSTEM_ERR); 424 } 425 /* We have mountd(8) PID in mountdpid variable. */ 426 kill(mountdpid, SIGHUP); 427 return (SA_OK); 428 } 429 430 static const sa_share_ops_t nfs_shareops = { 431 .enable_share = nfs_enable_share, 432 .disable_share = nfs_disable_share, 433 .is_shared = nfs_is_shared, 434 435 .validate_shareopts = nfs_validate_shareopts, 436 .update_shareopts = nfs_update_shareopts, 437 .clear_shareopts = nfs_clear_shareopts, 438 .commit_shares = nfs_commit_shares, 439 }; 440 441 /* 442 * Initializes the NFS functionality of libshare. 443 */ 444 void 445 libshare_nfs_init(void) 446 { 447 nfs_fstype = register_fstype("nfs", &nfs_shareops); 448 } 449