gr_util.c revision 245385
1/*- 2 * Copyright (c) 2008 Sean C. Farley <scf@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 * without modification, immediately at the beginning of the file. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/lib/libutil/gr_util.c 245385 2013-01-13 21:25:43Z mjg $"); 29 30#include <sys/param.h> 31#include <sys/errno.h> 32#include <sys/stat.h> 33 34#include <ctype.h> 35#include <err.h> 36#include <fcntl.h> 37#include <grp.h> 38#include <inttypes.h> 39#include <libutil.h> 40#include <paths.h> 41#include <stdbool.h> 42#include <stdio.h> 43#include <stdlib.h> 44#include <string.h> 45#include <unistd.h> 46 47static int lockfd = -1; 48static char group_dir[PATH_MAX]; 49static char group_file[PATH_MAX]; 50static char tempname[PATH_MAX]; 51static int initialized; 52 53static const char group_line_format[] = "%s:%s:%ju:"; 54 55/* 56 * Initialize statics 57 */ 58int 59gr_init(const char *dir, const char *group) 60{ 61 62 if (dir == NULL) { 63 strcpy(group_dir, _PATH_ETC); 64 } else { 65 if (strlen(dir) >= sizeof(group_dir)) { 66 errno = ENAMETOOLONG; 67 return (-1); 68 } 69 strcpy(group_dir, dir); 70 } 71 72 if (group == NULL) { 73 if (dir == NULL) { 74 strcpy(group_file, _PATH_GROUP); 75 } else if (snprintf(group_file, sizeof(group_file), "%s/group", 76 group_dir) > (int)sizeof(group_file)) { 77 errno = ENAMETOOLONG; 78 return (-1); 79 } 80 } else { 81 if (strlen(group) >= sizeof(group_file)) { 82 errno = ENAMETOOLONG; 83 return (-1); 84 } 85 strcpy(group_file, group); 86 } 87 88 initialized = 1; 89 return (0); 90} 91 92/* 93 * Lock the group file 94 */ 95int 96gr_lock(void) 97{ 98 if (*group_file == '\0') 99 return (-1); 100 101 for (;;) { 102 struct stat st; 103 104 lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0); 105 if (lockfd == -1) { 106 if (errno == EWOULDBLOCK) { 107 errx(1, "the group file is busy"); 108 } else { 109 err(1, "could not lock the group file: "); 110 } 111 } 112 if (fstat(lockfd, &st) == -1) 113 err(1, "fstat() failed: "); 114 if (st.st_nlink != 0) 115 break; 116 close(lockfd); 117 lockfd = -1; 118 } 119 return (lockfd); 120} 121 122/* 123 * Create and open a presmuably safe temp file for editing group data 124 */ 125int 126gr_tmp(int mfd) 127{ 128 char buf[8192]; 129 ssize_t nr; 130 const char *p; 131 int tfd; 132 133 if (*group_file == '\0') 134 return (-1); 135 if ((p = strrchr(group_file, '/'))) 136 ++p; 137 else 138 p = group_file; 139 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX", 140 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) { 141 errno = ENAMETOOLONG; 142 return (-1); 143 } 144 if ((tfd = mkstemp(tempname)) == -1) 145 return (-1); 146 if (mfd != -1) { 147 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 148 if (write(tfd, buf, (size_t)nr) != nr) 149 break; 150 if (nr != 0) { 151 unlink(tempname); 152 *tempname = '\0'; 153 close(tfd); 154 return (-1); 155 } 156 } 157 return (tfd); 158} 159 160/* 161 * Copy the group file from one descriptor to another, replacing, deleting 162 * or adding a single record on the way. 163 */ 164int 165gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) 166{ 167 char buf[8192], *end, *line, *p, *q, *r, t; 168 struct group *fgr; 169 const struct group *sgr; 170 size_t len; 171 int eof, readlen; 172 173 sgr = gr; 174 if (gr == NULL) { 175 line = NULL; 176 if (old_gr == NULL) 177 return (-1); 178 sgr = old_gr; 179 } else if ((line = gr_make(gr)) == NULL) 180 return (-1); 181 182 eof = 0; 183 len = 0; 184 p = q = end = buf; 185 for (;;) { 186 /* find the end of the current line */ 187 for (p = q; q < end && *q != '\0'; ++q) 188 if (*q == '\n') 189 break; 190 191 /* if we don't have a complete line, fill up the buffer */ 192 if (q >= end) { 193 if (eof) 194 break; 195 if ((size_t)(q - p) >= sizeof(buf)) { 196 warnx("group line too long"); 197 errno = EINVAL; /* hack */ 198 goto err; 199 } 200 if (p < end) { 201 q = memmove(buf, p, end -p); 202 end -= p - buf; 203 } else { 204 p = q = end = buf; 205 } 206 readlen = read(ffd, end, sizeof(buf) - (end -buf)); 207 if (readlen == -1) 208 goto err; 209 else 210 len = (size_t)readlen; 211 if (len == 0 && p == buf) 212 break; 213 end += len; 214 len = end - buf; 215 if (len < (ssize_t)sizeof(buf)) { 216 eof = 1; 217 if (len > 0 && buf[len -1] != '\n') 218 ++len, *end++ = '\n'; 219 } 220 continue; 221 } 222 223 /* is it a blank line or a comment? */ 224 for (r = p; r < q && isspace(*r); ++r) 225 /* nothing */; 226 if (r == q || *r == '#') { 227 /* yep */ 228 if (write(tfd, p, q -p + 1) != q - p + 1) 229 goto err; 230 ++q; 231 continue; 232 } 233 234 /* is it the one we're looking for? */ 235 236 t = *q; 237 *q = '\0'; 238 239 fgr = gr_scan(r); 240 241 /* fgr is either a struct group for the current line, 242 * or NULL if the line is malformed. 243 */ 244 245 *q = t; 246 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) { 247 /* nope */ 248 if (fgr != NULL) 249 free(fgr); 250 if (write(tfd, p, q - p + 1) != q - p + 1) 251 goto err; 252 ++q; 253 continue; 254 } 255 if (old_gr && !gr_equal(fgr, old_gr)) { 256 warnx("entry inconsistent"); 257 free(fgr); 258 errno = EINVAL; /* hack */ 259 goto err; 260 } 261 free(fgr); 262 263 /* it is, replace or remove it */ 264 if (line != NULL) { 265 len = strlen(line); 266 if (write(tfd, line, len) != (int) len) 267 goto err; 268 } else { 269 /* when removed, avoid the \n */ 270 q++; 271 } 272 /* we're done, just copy the rest over */ 273 for (;;) { 274 if (write(tfd, q, end - q) != end - q) 275 goto err; 276 q = buf; 277 readlen = read(ffd, buf, sizeof(buf)); 278 if (readlen == 0) 279 break; 280 else 281 len = (size_t)readlen; 282 if (readlen == -1) 283 goto err; 284 end = buf + len; 285 } 286 goto done; 287 } 288 289 /* if we got here, we didn't find the old entry */ 290 if (line == NULL) { 291 errno = ENOENT; 292 goto err; 293 } 294 len = strlen(line); 295 if ((size_t)write(tfd, line, len) != len || 296 write(tfd, "\n", 1) != 1) 297 goto err; 298 done: 299 if (line != NULL) 300 free(line); 301 return (0); 302 err: 303 if (line != NULL) 304 free(line); 305 return (-1); 306} 307 308/* 309 * Regenerate the group file 310 */ 311int 312gr_mkdb(void) 313{ 314 if (chmod(tempname, 0644) != 0) 315 return (-1); 316 317 return (rename(tempname, group_file)); 318} 319 320/* 321 * Clean up. Preserver errno for the caller's convenience. 322 */ 323void 324gr_fini(void) 325{ 326 int serrno; 327 328 if (!initialized) 329 return; 330 initialized = 0; 331 serrno = errno; 332 if (*tempname != '\0') { 333 unlink(tempname); 334 *tempname = '\0'; 335 } 336 if (lockfd != -1) 337 close(lockfd); 338 errno = serrno; 339} 340 341/* 342 * Compares two struct group's. 343 */ 344int 345gr_equal(const struct group *gr1, const struct group *gr2) 346{ 347 int gr1_ndx; 348 int gr2_ndx; 349 350 /* Check that the non-member information is the same. */ 351 if (gr1->gr_name == NULL || gr2->gr_name == NULL) { 352 if (gr1->gr_name != gr2->gr_name) 353 return (false); 354 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0) 355 return (false); 356 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) { 357 if (gr1->gr_passwd != gr2->gr_passwd) 358 return (false); 359 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0) 360 return (false); 361 if (gr1->gr_gid != gr2->gr_gid) 362 return (false); 363 364 /* Check all members in both groups. */ 365 if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) { 366 if (gr1->gr_mem != gr2->gr_mem) 367 return (false); 368 } else { 369 for (gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++) { 370 for (gr2_ndx = 0;; gr2_ndx++) { 371 if (gr2->gr_mem[gr2_ndx] == NULL) 372 return (false); 373 if (strcmp(gr1->gr_mem[gr1_ndx], 374 gr2->gr_mem[gr2_ndx]) == 0) { 375 break; 376 } 377 } 378 } 379 380 /* Check that group2 does not have more members than group1. */ 381 if (gr2->gr_mem[gr1_ndx] != NULL) 382 return (false); 383 } 384 385 return (true); 386} 387 388/* 389 * Make a group line out of a struct group. 390 */ 391char * 392gr_make(const struct group *gr) 393{ 394 char *line; 395 size_t line_size; 396 int ndx; 397 398 /* Calculate the length of the group line. */ 399 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 400 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 401 if (gr->gr_mem != NULL) { 402 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 403 line_size += strlen(gr->gr_mem[ndx]) + 1; 404 if (ndx > 0) 405 line_size--; 406 } 407 408 /* Create the group line and fill it. */ 409 if ((line = malloc(line_size)) == NULL) 410 return (NULL); 411 snprintf(line, line_size, group_line_format, gr->gr_name, gr->gr_passwd, 412 (uintmax_t)gr->gr_gid); 413 if (gr->gr_mem != NULL) 414 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 415 strcat(line, gr->gr_mem[ndx]); 416 if (gr->gr_mem[ndx + 1] != NULL) 417 strcat(line, ","); 418 } 419 420 return (line); 421} 422 423/* 424 * Duplicate a struct group. 425 */ 426struct group * 427gr_dup(const struct group *gr) 428{ 429 struct group *newgr; 430 char *dst; 431 size_t len; 432 int ndx; 433 int num_mem; 434 435 /* Calculate size of the group. */ 436 len = sizeof(*newgr); 437 if (gr->gr_name != NULL) 438 len += strlen(gr->gr_name) + 1; 439 if (gr->gr_passwd != NULL) 440 len += strlen(gr->gr_passwd) + 1; 441 if (gr->gr_mem != NULL) { 442 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) 443 len += strlen(gr->gr_mem[num_mem]) + 1; 444 len += (num_mem + 1) * sizeof(*gr->gr_mem); 445 } else 446 num_mem = -1; 447 /* Create new group and copy old group into it. */ 448 if ((newgr = malloc(len)) == NULL) 449 return (NULL); 450 /* point new gr_mem to end of struct + 1 */ 451 if (gr->gr_mem != NULL) 452 newgr->gr_mem = (char **)(newgr + 1); 453 else 454 newgr->gr_mem = NULL; 455 /* point dst after the end of all the gr_mem pointers in newgr */ 456 dst = (char *)&newgr->gr_mem[num_mem + 1]; 457 if (gr->gr_name != NULL) { 458 newgr->gr_name = dst; 459 dst = stpcpy(dst, gr->gr_name) + 1; 460 } else { 461 newgr->gr_name = NULL; 462 } 463 if (gr->gr_passwd != NULL) { 464 newgr->gr_passwd = dst; 465 dst = stpcpy(dst, gr->gr_passwd) + 1; 466 } else { 467 newgr->gr_passwd = NULL; 468 } 469 newgr->gr_gid = gr->gr_gid; 470 if (gr->gr_mem != NULL) { 471 for (ndx = 0; ndx < num_mem; ndx++) { 472 newgr->gr_mem[ndx] = dst; 473 dst = stpcpy(dst, gr->gr_mem[ndx]) + 1; 474 } 475 newgr->gr_mem[ndx] = NULL; 476 } 477 return (newgr); 478} 479 480/* 481 * Add a new member name to a struct group. 482 */ 483struct group * 484gr_add(struct group *gr, char *newmember) 485{ 486 size_t mlen; 487 int num_mem=0; 488 char **members; 489 struct group *newgr; 490 491 if (newmember == NULL) 492 return(gr_dup(gr)); 493 494 if (gr->gr_mem != NULL) { 495 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) { 496 if (strcmp(gr->gr_mem[num_mem], newmember) == 0) { 497 errno = EEXIST; 498 return (NULL); 499 } 500 } 501 } 502 /* Allocate enough for current pointers + 1 more and NULL marker */ 503 mlen = (num_mem + 2) * sizeof(*gr->gr_mem); 504 if ((members = malloc(mlen)) == NULL) 505 return (NULL); 506 memcpy(members, gr->gr_mem, num_mem * sizeof(*gr->gr_mem)); 507 members[num_mem++] = newmember; 508 members[num_mem] = NULL; 509 gr->gr_mem = members; 510 newgr = gr_dup(gr); 511 free(members); 512 return (newgr); 513} 514 515/* 516 * Scan a line and place it into a group structure. 517 */ 518static bool 519__gr_scan(char *line, struct group *gr) 520{ 521 char *loc; 522 int ndx; 523 524 /* Assign non-member information to structure. */ 525 gr->gr_name = line; 526 if ((loc = strchr(line, ':')) == NULL) 527 return (false); 528 *loc = '\0'; 529 gr->gr_passwd = loc + 1; 530 if (*gr->gr_passwd == ':') 531 *gr->gr_passwd = '\0'; 532 else { 533 if ((loc = strchr(loc + 1, ':')) == NULL) 534 return (false); 535 *loc = '\0'; 536 } 537 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 538 return (false); 539 540 /* Assign member information to structure. */ 541 if ((loc = strchr(loc + 1, ':')) == NULL) 542 return (false); 543 line = loc + 1; 544 gr->gr_mem = NULL; 545 ndx = 0; 546 do { 547 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 548 (ndx + 1)); 549 if (gr->gr_mem == NULL) 550 return (false); 551 552 /* Skip locations without members (i.e., empty string). */ 553 do { 554 gr->gr_mem[ndx] = strsep(&line, ","); 555 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 556 } while (gr->gr_mem[ndx++] != NULL); 557 558 return (true); 559} 560 561/* 562 * Create a struct group from a line. 563 */ 564struct group * 565gr_scan(const char *line) 566{ 567 struct group gr; 568 char *line_copy; 569 struct group *new_gr; 570 571 if ((line_copy = strdup(line)) == NULL) 572 return (NULL); 573 if (!__gr_scan(line_copy, &gr)) { 574 free(line_copy); 575 return (NULL); 576 } 577 new_gr = gr_dup(&gr); 578 free(line_copy); 579 if (gr.gr_mem != NULL) 580 free(gr.gr_mem); 581 582 return (new_gr); 583} 584