1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or https://opensource.org/licenses/CDDL-1.0. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 23 #include <sys/types.h> 24 #include <sys/stat.h> 25 #include <sys/file.h> 26 #include <fcntl.h> 27 #include <ctype.h> 28 #include <stdio.h> 29 #include <errno.h> 30 #include <libshare.h> 31 #include <unistd.h> 32 #include "nfs.h" 33 34 35 /* 36 * nfs_exports_[lock|unlock] are used to guard against conconcurrent 37 * updates to the exports file. Each protocol is responsible for 38 * providing the necessary locking to ensure consistency. 39 */ 40 static int 41 nfs_exports_lock(const char *name, int *nfs_lock_fd) 42 { 43 int err; 44 45 *nfs_lock_fd = open(name, O_RDWR | O_CREAT | O_CLOEXEC, 0600); 46 if (*nfs_lock_fd == -1) { 47 err = errno; 48 fprintf(stderr, "failed to lock %s: %s\n", name, strerror(err)); 49 return (err); 50 } 51 52 while ((err = flock(*nfs_lock_fd, LOCK_EX)) != 0 && errno == EINTR) 53 ; 54 if (err != 0) { 55 err = errno; 56 fprintf(stderr, "failed to lock %s: %s\n", name, strerror(err)); 57 (void) close(*nfs_lock_fd); 58 *nfs_lock_fd = -1; 59 return (err); 60 } 61 62 return (0); 63 } 64 65 static void 66 nfs_exports_unlock(const char *name, int *nfs_lock_fd) 67 { 68 verify(*nfs_lock_fd > 0); 69 70 if (flock(*nfs_lock_fd, LOCK_UN) != 0) 71 fprintf(stderr, "failed to unlock %s: %s\n", 72 name, strerror(errno)); 73 74 (void) close(*nfs_lock_fd); 75 *nfs_lock_fd = -1; 76 } 77 78 struct tmpfile { 79 /* 80 * This only needs to be as wide as ZFS_EXPORTS_FILE and mktemp suffix, 81 * 64 is more than enough. 82 */ 83 char name[64]; 84 FILE *fp; 85 }; 86 87 static boolean_t 88 nfs_init_tmpfile(const char *prefix, const char *mdir, struct tmpfile *tmpf) 89 { 90 if (mdir != NULL && 91 mkdir(mdir, 0755) < 0 && 92 errno != EEXIST) { 93 fprintf(stderr, "failed to create %s: %s\n", 94 // cppcheck-suppress uninitvar 95 mdir, strerror(errno)); 96 return (B_FALSE); 97 } 98 99 strlcpy(tmpf->name, prefix, sizeof (tmpf->name)); 100 strlcat(tmpf->name, ".XXXXXXXX", sizeof (tmpf->name) - strlen(prefix)); 101 102 int fd = mkostemp(tmpf->name, O_CLOEXEC); 103 if (fd == -1) { 104 fprintf(stderr, "Unable to create temporary file: %s", 105 strerror(errno)); 106 return (B_FALSE); 107 } 108 109 tmpf->fp = fdopen(fd, "w+"); 110 if (tmpf->fp == NULL) { 111 fprintf(stderr, "Unable to reopen temporary file: %s", 112 strerror(errno)); 113 close(fd); 114 return (B_FALSE); 115 } 116 117 return (B_TRUE); 118 } 119 120 static void 121 nfs_abort_tmpfile(struct tmpfile *tmpf) 122 { 123 unlink(tmpf->name); 124 fclose(tmpf->fp); 125 } 126 127 static int 128 nfs_fini_tmpfile(const char *exports, struct tmpfile *tmpf) 129 { 130 if (fflush(tmpf->fp) != 0) { 131 fprintf(stderr, "Failed to write to temporary file: %s\n", 132 strerror(errno)); 133 nfs_abort_tmpfile(tmpf); 134 return (SA_SYSTEM_ERR); 135 } 136 137 if (rename(tmpf->name, exports) == -1) { 138 fprintf(stderr, "Unable to rename %s -> %s: %s\n", 139 tmpf->name, exports, strerror(errno)); 140 nfs_abort_tmpfile(tmpf); 141 return (SA_SYSTEM_ERR); 142 } 143 144 (void) fchmod(fileno(tmpf->fp), 0644); 145 fclose(tmpf->fp); 146 return (SA_OK); 147 } 148 149 int 150 nfs_escape_mountpoint(const char *mp, char **out, boolean_t *need_free) 151 { 152 if (strpbrk(mp, "\t\n\v\f\r \\") == NULL) { 153 *out = (char *)mp; 154 *need_free = B_FALSE; 155 return (SA_OK); 156 } else { 157 size_t len = strlen(mp); 158 *out = malloc(len * 4 + 1); 159 if (!*out) 160 return (SA_NO_MEMORY); 161 *need_free = B_TRUE; 162 163 char *oc = *out; 164 for (const char *c = mp; c < mp + len; ++c) 165 if (memchr("\t\n\v\f\r \\", *c, 166 strlen("\t\n\v\f\r \\"))) { 167 sprintf(oc, "\\%03hho", *c); 168 oc += 4; 169 } else 170 *oc++ = *c; 171 *oc = '\0'; 172 } 173 174 return (SA_OK); 175 } 176 177 static int 178 nfs_process_exports(const char *exports, const char *mountpoint, 179 boolean_t (*cbk)(void *userdata, char *line, boolean_t found_mountpoint), 180 void *userdata) 181 { 182 int error = SA_OK; 183 boolean_t cont = B_TRUE; 184 185 FILE *oldfp = fopen(exports, "re"); 186 if (oldfp != NULL) { 187 boolean_t need_mp_free; 188 char *mp; 189 if ((error = nfs_escape_mountpoint(mountpoint, 190 &mp, &need_mp_free)) != SA_OK) { 191 (void) fclose(oldfp); 192 return (error); 193 } 194 195 char *buf = NULL, *sep; 196 size_t buflen = 0, mplen = strlen(mp); 197 198 while (cont && getline(&buf, &buflen, oldfp) != -1) { 199 if (buf[0] == '\n' || buf[0] == '#') 200 continue; 201 202 cont = cbk(userdata, buf, 203 (sep = strpbrk(buf, "\t \n")) != NULL && 204 sep - buf == mplen && 205 strncmp(buf, mp, mplen) == 0); 206 } 207 free(buf); 208 if (need_mp_free) 209 free(mp); 210 211 if (ferror(oldfp) != 0) 212 error = ferror(oldfp); 213 214 if (fclose(oldfp) != 0) { 215 fprintf(stderr, "Unable to close file %s: %s\n", 216 exports, strerror(errno)); 217 error = error != SA_OK ? error : SA_SYSTEM_ERR; 218 } 219 } 220 221 return (error); 222 } 223 224 static boolean_t 225 nfs_copy_entries_cb(void *userdata, char *line, boolean_t found_mountpoint) 226 { 227 FILE *newfp = userdata; 228 if (!found_mountpoint) 229 fputs(line, newfp); 230 return (B_TRUE); 231 } 232 233 /* 234 * Copy all entries from the exports file (if it exists) to newfp, 235 * omitting any entries for the specified mountpoint. 236 */ 237 static int 238 nfs_copy_entries(FILE *newfp, const char *exports, const char *mountpoint) 239 { 240 fputs(FILE_HEADER, newfp); 241 242 int error = nfs_process_exports( 243 exports, mountpoint, nfs_copy_entries_cb, newfp); 244 245 if (error == SA_OK && ferror(newfp) != 0) 246 error = ferror(newfp); 247 248 return (error); 249 } 250 251 int 252 nfs_toggle_share(const char *lockfile, const char *exports, 253 const char *expdir, sa_share_impl_t impl_share, 254 int(*cbk)(sa_share_impl_t impl_share, FILE *tmpfile)) 255 { 256 int error, nfs_lock_fd = -1; 257 struct tmpfile tmpf; 258 259 if (!nfs_init_tmpfile(exports, expdir, &tmpf)) 260 return (SA_SYSTEM_ERR); 261 262 error = nfs_exports_lock(lockfile, &nfs_lock_fd); 263 if (error != 0) { 264 nfs_abort_tmpfile(&tmpf); 265 return (error); 266 } 267 268 error = nfs_copy_entries(tmpf.fp, exports, impl_share->sa_mountpoint); 269 if (error != SA_OK) 270 goto fullerr; 271 272 error = cbk(impl_share, tmpf.fp); 273 if (error != SA_OK) 274 goto fullerr; 275 276 error = nfs_fini_tmpfile(exports, &tmpf); 277 nfs_exports_unlock(lockfile, &nfs_lock_fd); 278 return (error); 279 280 fullerr: 281 nfs_abort_tmpfile(&tmpf); 282 nfs_exports_unlock(lockfile, &nfs_lock_fd); 283 return (error); 284 } 285 286 void 287 nfs_reset_shares(const char *lockfile, const char *exports) 288 { 289 int nfs_lock_fd = -1; 290 291 if (nfs_exports_lock(lockfile, &nfs_lock_fd) == 0) { 292 (void) ! truncate(exports, 0); 293 nfs_exports_unlock(lockfile, &nfs_lock_fd); 294 } 295 } 296 297 static boolean_t 298 nfs_is_shared_cb(void *userdata, char *line, boolean_t found_mountpoint) 299 { 300 (void) line; 301 302 boolean_t *found = userdata; 303 *found = found_mountpoint; 304 return (!found_mountpoint); 305 } 306 307 boolean_t 308 nfs_is_shared_impl(const char *exports, sa_share_impl_t impl_share) 309 { 310 boolean_t found = B_FALSE; 311 nfs_process_exports(exports, impl_share->sa_mountpoint, 312 nfs_is_shared_cb, &found); 313 return (found); 314 } 315