1 /*- 2 * Copyright (c) 2010 Ed Schouten <ed@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 AUTHOR 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 AUTHOR 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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include "namespace.h" 31 #include <sys/endian.h> 32 #include <sys/stat.h> 33 #include <sys/uio.h> 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <stdio.h> 37 #include <string.h> 38 #include <unistd.h> 39 #include <utmpx.h> 40 #include "utxdb.h" 41 #include "un-namespace.h" 42 43 static FILE * 44 futx_open(const char *file) 45 { 46 FILE *fp; 47 struct stat sb; 48 int fd; 49 50 fd = _open(file, O_CREAT|O_RDWR|O_EXLOCK, 0644); 51 if (fd < 0) 52 return (NULL); 53 54 /* Safety check: never use broken files. */ 55 if (_fstat(fd, &sb) != -1 && sb.st_size % sizeof(struct futx) != 0) { 56 _close(fd); 57 errno = EFTYPE; 58 return (NULL); 59 } 60 61 fp = fdopen(fd, "r+"); 62 if (fp == NULL) { 63 _close(fd); 64 return (NULL); 65 } 66 return (fp); 67 } 68 69 static int 70 utx_active_add(const struct futx *fu) 71 { 72 FILE *fp; 73 struct futx fe; 74 off_t partial; 75 int error, ret; 76 77 partial = -1; 78 ret = 0; 79 80 /* 81 * Register user login sessions. Overwrite entries of sessions 82 * that have already been terminated. 83 */ 84 fp = futx_open(_PATH_UTX_ACTIVE); 85 if (fp == NULL) 86 return (-1); 87 while (fread(&fe, sizeof(fe), 1, fp) == 1) { 88 switch (fe.fu_type) { 89 case BOOT_TIME: 90 /* Leave these intact. */ 91 break; 92 case USER_PROCESS: 93 case INIT_PROCESS: 94 case LOGIN_PROCESS: 95 case DEAD_PROCESS: 96 /* Overwrite when ut_id matches. */ 97 if (memcmp(fu->fu_id, fe.fu_id, sizeof(fe.fu_id)) == 98 0) { 99 ret = fseeko(fp, -(off_t)sizeof(fe), SEEK_CUR); 100 goto exact; 101 } 102 if (fe.fu_type != DEAD_PROCESS) 103 break; 104 /* FALLTHROUGH */ 105 default: 106 /* Allow us to overwrite unused records. */ 107 if (partial == -1) { 108 partial = ftello(fp); 109 /* 110 * Distinguish errors from valid values so we 111 * don't overwrite good data by accident. 112 */ 113 if (partial != -1) 114 partial -= (off_t)sizeof(fe); 115 } 116 break; 117 } 118 } 119 120 /* 121 * No exact match found. Use the partial match. If no partial 122 * match was found, just append a new record. 123 */ 124 if (partial != -1) 125 ret = fseeko(fp, partial, SEEK_SET); 126 exact: 127 if (ret == -1) 128 error = errno; 129 else if (fwrite(fu, sizeof(*fu), 1, fp) < 1) 130 error = errno; 131 else 132 error = 0; 133 fclose(fp); 134 errno = error; 135 return (error == 0 ? 0 : 1); 136 } 137 138 static int 139 utx_active_remove(struct futx *fu) 140 { 141 FILE *fp; 142 struct futx fe; 143 int error, ret; 144 145 /* 146 * Remove user login sessions, having the same ut_id. 147 */ 148 fp = futx_open(_PATH_UTX_ACTIVE); 149 if (fp == NULL) 150 return (-1); 151 error = ESRCH; 152 ret = -1; 153 while (fread(&fe, sizeof(fe), 1, fp) == 1 && ret != 0) 154 switch (fe.fu_type) { 155 case USER_PROCESS: 156 case INIT_PROCESS: 157 case LOGIN_PROCESS: 158 if (memcmp(fu->fu_id, fe.fu_id, sizeof(fe.fu_id)) != 0) 159 continue; 160 161 /* Terminate session. */ 162 if (fseeko(fp, -(off_t)sizeof(fe), SEEK_CUR) == -1) 163 error = errno; 164 else if (fwrite(fu, sizeof(*fu), 1, fp) < 1) 165 error = errno; 166 else 167 ret = 0; 168 169 } 170 171 fclose(fp); 172 errno = error; 173 return (ret); 174 } 175 176 static void 177 utx_active_init(const struct futx *fu) 178 { 179 int fd; 180 181 /* Initialize utx.active with a single BOOT_TIME record. */ 182 fd = _open(_PATH_UTX_ACTIVE, O_CREAT|O_RDWR|O_TRUNC, 0644); 183 if (fd < 0) 184 return; 185 _write(fd, fu, sizeof(*fu)); 186 _close(fd); 187 } 188 189 static void 190 utx_active_purge(void) 191 { 192 193 truncate(_PATH_UTX_ACTIVE, 0); 194 } 195 196 static int 197 utx_lastlogin_add(const struct futx *fu) 198 { 199 struct futx fe; 200 FILE *fp; 201 int error, ret; 202 203 ret = 0; 204 205 /* 206 * Write an entry to lastlogin. Overwrite the entry if the 207 * current user already has an entry. If not, append a new 208 * entry. 209 */ 210 fp = futx_open(_PATH_UTX_LASTLOGIN); 211 if (fp == NULL) 212 return (-1); 213 while (fread(&fe, sizeof fe, 1, fp) == 1) { 214 if (strncmp(fu->fu_user, fe.fu_user, sizeof fe.fu_user) != 0) 215 continue; 216 217 /* Found a previous lastlogin entry for this user. */ 218 ret = fseeko(fp, -(off_t)sizeof fe, SEEK_CUR); 219 break; 220 } 221 if (ret == -1) 222 error = errno; 223 else if (fwrite(fu, sizeof *fu, 1, fp) < 1) { 224 error = errno; 225 ret = -1; 226 } 227 fclose(fp); 228 errno = error; 229 return (ret); 230 } 231 232 static void 233 utx_lastlogin_upgrade(void) 234 { 235 struct stat sb; 236 int fd; 237 238 fd = _open(_PATH_UTX_LASTLOGIN, O_RDWR, 0644); 239 if (fd < 0) 240 return; 241 242 /* 243 * Truncate broken lastlogin files. In the future we should 244 * check for older versions of the file format here and try to 245 * upgrade it. 246 */ 247 if (_fstat(fd, &sb) != -1 && sb.st_size % sizeof(struct futx) != 0) 248 ftruncate(fd, 0); 249 _close(fd); 250 } 251 252 static int 253 utx_log_add(const struct futx *fu) 254 { 255 struct iovec vec[2]; 256 int error, fd; 257 uint16_t l; 258 259 /* 260 * Append an entry to the log file. We only need to append 261 * records to this file, so to conserve space, trim any trailing 262 * zero-bytes. Prepend a length field, indicating the length of 263 * the record, excluding the length field itself. 264 */ 265 for (l = sizeof(*fu); l > 0 && ((const char *)fu)[l - 1] == '\0'; l--) ; 266 vec[0].iov_base = &l; 267 vec[0].iov_len = sizeof(l); 268 vec[1].iov_base = __DECONST(void *, fu); 269 vec[1].iov_len = l; 270 l = htobe16(l); 271 272 fd = _open(_PATH_UTX_LOG, O_CREAT|O_WRONLY|O_APPEND, 0644); 273 if (fd < 0) 274 return (-1); 275 if (_writev(fd, vec, 2) == -1) 276 error = errno; 277 else 278 error = 0; 279 _close(fd); 280 errno = error; 281 return (error == 0 ? 0 : 1); 282 } 283 284 struct utmpx * 285 pututxline(const struct utmpx *utmpx) 286 { 287 struct futx fu; 288 int bad; 289 290 bad = 0; 291 292 utx_to_futx(utmpx, &fu); 293 294 switch (fu.fu_type) { 295 case BOOT_TIME: 296 utx_active_init(&fu); 297 utx_lastlogin_upgrade(); 298 break; 299 case SHUTDOWN_TIME: 300 utx_active_purge(); 301 break; 302 case OLD_TIME: 303 case NEW_TIME: 304 break; 305 case USER_PROCESS: 306 bad |= utx_active_add(&fu); 307 bad |= utx_lastlogin_add(&fu); 308 break; 309 #if 0 /* XXX: Are these records of any use to us? */ 310 case INIT_PROCESS: 311 case LOGIN_PROCESS: 312 bad |= utx_active_add(&fu); 313 break; 314 #endif 315 case DEAD_PROCESS: 316 /* 317 * In case writing a logout entry fails, never attempt 318 * to write it to utx.log. The logout entry's ut_id 319 * might be invalid. 320 */ 321 if (utx_active_remove(&fu) != 0) 322 return (NULL); 323 break; 324 default: 325 errno = EINVAL; 326 return (NULL); 327 } 328 329 bad |= utx_log_add(&fu); 330 return (bad ? NULL : futx_to_utx(&fu)); 331 } 332