gr_util.c revision 272461
119304Speter/*- 219304Speter * Copyright (c) 2008 Sean C. Farley <scf@FreeBSD.org> 319304Speter * All rights reserved. 419304Speter * 519304Speter * Redistribution and use in source and binary forms, with or without 619304Speter * modification, are permitted provided that the following conditions 719304Speter * are met: 819304Speter * 1. Redistributions of source code must retain the above copyright 919304Speter * notice, this list of conditions and the following disclaimer, 1019304Speter * without modification, immediately at the beginning of the file. 1119304Speter * 2. Redistributions in binary form must reproduce the above copyright 1219304Speter * notice, this list of conditions and the following disclaimer in the 13254225Speter * documentation and/or other materials provided with the distribution. 1419304Speter * 1519304Speter * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1619304Speter * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1719304Speter * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18254225Speter * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1919304Speter * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 2019304Speter * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2119304Speter * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2219304Speter * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2319304Speter * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2419304Speter * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2519304Speter */ 2619304Speter 2719304Speter#include <sys/cdefs.h> 2819304Speter__FBSDID("$FreeBSD: releng/10.1/lib/libutil/gr_util.c 248102 2013-03-09 13:30:06Z db $"); 2919304Speter 3019304Speter#include <sys/param.h> 3119304Speter#include <sys/errno.h> 3219304Speter#include <sys/stat.h> 3319304Speter 3419304Speter#include <ctype.h> 3519304Speter#include <err.h> 36254225Speter#include <fcntl.h> 37254225Speter#include <grp.h> 38254225Speter#include <inttypes.h> 39254225Speter#include <libutil.h> 40254225Speter#include <paths.h> 41254225Speter#include <stdbool.h> 42254225Speter#include <stdio.h> 4319304Speter#include <stdlib.h> 4419304Speter#include <string.h> 4519304Speter#include <unistd.h> 4619304Speter 4719304Speterstatic int lockfd = -1; 4819304Speterstatic char group_dir[PATH_MAX]; 49254225Speterstatic char group_file[PATH_MAX]; 50254225Speterstatic char tempname[PATH_MAX]; 5119304Speterstatic int initialized; 5219304Speterstatic size_t grmemlen(const struct group *, const char *, int *); 5319304Speterstatic struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx); 5419304Speter 5519304Speter/* 5619304Speter * Initialize statics 5719304Speter */ 5819304Speterint 5919304Spetergr_init(const char *dir, const char *group) 6019304Speter{ 6119304Speter 6219304Speter if (dir == NULL) { 6319304Speter strcpy(group_dir, _PATH_ETC); 6419304Speter } else { 6519304Speter if (strlen(dir) >= sizeof(group_dir)) { 6619304Speter errno = ENAMETOOLONG; 6719304Speter return (-1); 6819304Speter } 69254225Speter strcpy(group_dir, dir); 7019304Speter } 7119304Speter 7219304Speter if (group == NULL) { 7319304Speter if (dir == NULL) { 7419304Speter strcpy(group_file, _PATH_GROUP); 7519304Speter } else if (snprintf(group_file, sizeof(group_file), "%s/group", 7619304Speter group_dir) > (int)sizeof(group_file)) { 7719304Speter errno = ENAMETOOLONG; 7819304Speter return (-1); 7919304Speter } 8019304Speter } else { 8119304Speter if (strlen(group) >= sizeof(group_file)) { 8219304Speter errno = ENAMETOOLONG; 8319304Speter return (-1); 8419304Speter } 8519304Speter strcpy(group_file, group); 8619304Speter } 8719304Speter 8819304Speter initialized = 1; 8919304Speter return (0); 90254225Speter} 91254225Speter 9219304Speter/* 9319304Speter * Lock the group file 9419304Speter */ 9519304Speterint 9619304Spetergr_lock(void) 9719304Speter{ 9819304Speter if (*group_file == '\0') 9919304Speter return (-1); 10019304Speter 10119304Speter for (;;) { 10219304Speter struct stat st; 10319304Speter 104254225Speter lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0); 105254225Speter if (lockfd == -1) { 10619304Speter if (errno == EWOULDBLOCK) { 10719304Speter errx(1, "the group file is busy"); 10819304Speter } else { 10919304Speter err(1, "could not lock the group file: "); 11019304Speter } 11119304Speter } 11219304Speter if (fstat(lockfd, &st) == -1) 11319304Speter err(1, "fstat() failed: "); 11419304Speter if (st.st_nlink != 0) 11519304Speter break; 11619304Speter close(lockfd); 11719304Speter lockfd = -1; 11819304Speter } 11919304Speter return (lockfd); 12019304Speter} 12119304Speter 12219304Speter/* 12319304Speter * Create and open a presmuably safe temp file for editing group data 12419304Speter */ 12519304Speterint 126254225Spetergr_tmp(int mfd) 12719304Speter{ 12819304Speter char buf[8192]; 12919304Speter ssize_t nr; 13019304Speter const char *p; 131254225Speter int tfd; 13219304Speter 13319304Speter if (*group_file == '\0') 13419304Speter return (-1); 13519304Speter if ((p = strrchr(group_file, '/'))) 13619304Speter ++p; 13719304Speter else 138254225Speter p = group_file; 13919304Speter if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX", 14019304Speter (int)(p - group_file), group_file) >= (int)sizeof(tempname)) { 14119304Speter errno = ENAMETOOLONG; 14219304Speter return (-1); 14319304Speter } 14419304Speter if ((tfd = mkstemp(tempname)) == -1) 14519304Speter return (-1); 14619304Speter if (mfd != -1) { 14719304Speter while ((nr = read(mfd, buf, sizeof(buf))) > 0) 14819304Speter if (write(tfd, buf, (size_t)nr) != nr) 14919304Speter break; 15019304Speter if (nr != 0) { 15119304Speter unlink(tempname); 15219304Speter *tempname = '\0'; 15319304Speter close(tfd); 15419304Speter return (-1); 15519304Speter } 15619304Speter } 15719304Speter return (tfd); 15819304Speter} 15919304Speter 16019304Speter/* 16119304Speter * Copy the group file from one descriptor to another, replacing, deleting 16219304Speter * or adding a single record on the way. 16319304Speter */ 16419304Speterint 16519304Spetergr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) 16619304Speter{ 167254225Speter char buf[8192], *end, *line, *p, *q, *r, t; 16819304Speter struct group *fgr; 169254225Speter const struct group *sgr; 17019304Speter size_t len; 17119304Speter int eof, readlen; 17219304Speter 17319304Speter sgr = gr; 17419304Speter if (gr == NULL) { 17519304Speter line = NULL; 17619304Speter if (old_gr == NULL) 17719304Speter return (-1); 17819304Speter sgr = old_gr; 17919304Speter } else if ((line = gr_make(gr)) == NULL) 18019304Speter return (-1); 18119304Speter 18219304Speter eof = 0; 18319304Speter len = 0; 18419304Speter p = q = end = buf; 18519304Speter for (;;) { 18619304Speter /* find the end of the current line */ 18719304Speter for (p = q; q < end && *q != '\0'; ++q) 18819304Speter if (*q == '\n') 189254225Speter break; 19019304Speter 191254225Speter /* if we don't have a complete line, fill up the buffer */ 19219304Speter if (q >= end) { 19319304Speter if (eof) 19419304Speter break; 195254225Speter if ((size_t)(q - p) >= sizeof(buf)) { 19619304Speter warnx("group line too long"); 197254225Speter errno = EINVAL; /* hack */ 19819304Speter goto err; 19919304Speter } 20019304Speter if (p < end) { 20119304Speter q = memmove(buf, p, end -p); 20219304Speter end -= p - buf; 20319304Speter } else { 20419304Speter p = q = end = buf; 20519304Speter } 20619304Speter readlen = read(ffd, end, sizeof(buf) - (end -buf)); 20719304Speter if (readlen == -1) 20819304Speter goto err; 20919304Speter else 21019304Speter len = (size_t)readlen; 21119304Speter if (len == 0 && p == buf) 21219304Speter break; 21319304Speter end += len; 21419304Speter len = end - buf; 21519304Speter if (len < (ssize_t)sizeof(buf)) { 21619304Speter eof = 1; 217254225Speter if (len > 0 && buf[len -1] != '\n') 218254225Speter ++len, *end++ = '\n'; 21919304Speter } 22019304Speter continue; 22119304Speter } 22219304Speter 22319304Speter /* is it a blank line or a comment? */ 22419304Speter for (r = p; r < q && isspace(*r); ++r) 22519304Speter /* nothing */; 22619304Speter if (r == q || *r == '#') { 22719304Speter /* yep */ 22819304Speter if (write(tfd, p, q -p + 1) != q - p + 1) 22919304Speter goto err; 23019304Speter ++q; 231254225Speter continue; 23219304Speter } 23319304Speter 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. Preserves 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 * getgrnam can return gr_mem with a pointer to NULL. 366 * gr_dup and gr_add strip out this superfluous NULL, setting 367 * gr_mem to NULL for no members. 368 */ 369 if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) { 370 int i; 371 372 for (i = 0; gr1->gr_mem[i] != NULL; i++) { 373 if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0) 374 return (false); 375 } 376 } 377 /* Count number of members in both structs */ 378 gr2_ndx = 0; 379 if (gr2->gr_mem != NULL) 380 for(; gr2->gr_mem[gr2_ndx] != NULL; gr2_ndx++) 381 /* empty */; 382 gr1_ndx = 0; 383 if (gr1->gr_mem != NULL) 384 for(; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++) 385 /* empty */; 386 if (gr1_ndx != gr2_ndx) 387 return (false); 388 389 return (true); 390} 391 392/* 393 * Make a group line out of a struct group. 394 */ 395char * 396gr_make(const struct group *gr) 397{ 398 const char *group_line_format = "%s:%s:%ju:"; 399 const char *sep; 400 char *line; 401 char *p; 402 size_t line_size; 403 int ndx; 404 405 /* Calculate the length of the group line. */ 406 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 407 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 408 if (gr->gr_mem != NULL) { 409 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 410 line_size += strlen(gr->gr_mem[ndx]) + 1; 411 if (ndx > 0) 412 line_size--; 413 } 414 415 /* Create the group line and fill it. */ 416 if ((line = p = malloc(line_size)) == NULL) 417 return (NULL); 418 p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd, 419 (uintmax_t)gr->gr_gid); 420 if (gr->gr_mem != NULL) { 421 sep = ""; 422 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 423 p = stpcpy(p, sep); 424 p = stpcpy(p, gr->gr_mem[ndx]); 425 sep = ","; 426 } 427 } 428 429 return (line); 430} 431 432/* 433 * Duplicate a struct group. 434 */ 435struct group * 436gr_dup(const struct group *gr) 437{ 438 return (gr_add(gr, NULL)); 439} 440/* 441 * Add a new member name to a struct group. 442 */ 443struct group * 444gr_add(const struct group *gr, const char *newmember) 445{ 446 char *mem; 447 size_t len; 448 int num_mem; 449 450 num_mem = 0; 451 len = grmemlen(gr, newmember, &num_mem); 452 /* Create new group and copy old group into it. */ 453 if ((mem = malloc(len)) == NULL) 454 return (NULL); 455 return (grcopy(gr, mem, newmember, num_mem)); 456} 457 458/* It is safer to walk the pointers given at gr_mem since there is no 459 * guarantee the gr_mem + strings are contiguous in the given struct group 460 * but compactify the new group into the following form. 461 * 462 * The new struct is laid out like this in memory. The example given is 463 * for a group with two members only. 464 * 465 * { 466 * (char *name) 467 * (char *passwd) 468 * (int gid) 469 * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area 470 * gr_mem area 471 * (member1 *) 472 * (member2 *) 473 * (NULL) 474 * (name string) 475 * (passwd string) 476 * (member1 string) 477 * (member2 string) 478 * } 479 */ 480/* 481 * Copy the contents of a group plus given name to a preallocated group struct 482 */ 483static struct group * 484grcopy(const struct group *gr, char *dst, const char *name, int ndx) 485{ 486 int i; 487 struct group *newgr; 488 489 newgr = (struct group *)(void *)dst; /* avoid alignment warning */ 490 dst += sizeof(*newgr); 491 if (ndx != 0) { 492 newgr->gr_mem = (char **)(void *)(dst); /* avoid alignment warning */ 493 dst += (ndx + 1) * sizeof(*newgr->gr_mem); 494 } else 495 newgr->gr_mem = NULL; 496 if (gr->gr_name != NULL) { 497 newgr->gr_name = dst; 498 dst = stpcpy(dst, gr->gr_name) + 1; 499 } else 500 newgr->gr_name = NULL; 501 if (gr->gr_passwd != NULL) { 502 newgr->gr_passwd = dst; 503 dst = stpcpy(dst, gr->gr_passwd) + 1; 504 } else 505 newgr->gr_passwd = NULL; 506 newgr->gr_gid = gr->gr_gid; 507 i = 0; 508 /* Original group struct might have a NULL gr_mem */ 509 if (gr->gr_mem != NULL) { 510 for (; gr->gr_mem[i] != NULL; i++) { 511 newgr->gr_mem[i] = dst; 512 dst = stpcpy(dst, gr->gr_mem[i]) + 1; 513 } 514 } 515 /* If name is not NULL, newgr->gr_mem is known to be not NULL */ 516 if (name != NULL) { 517 newgr->gr_mem[i++] = dst; 518 dst = stpcpy(dst, name) + 1; 519 } 520 /* if newgr->gr_mem is not NULL add NULL marker */ 521 if (newgr->gr_mem != NULL) 522 newgr->gr_mem[i] = NULL; 523 524 return (newgr); 525} 526 527/* 528 * Calculate length of a struct group + given name 529 */ 530static size_t 531grmemlen(const struct group *gr, const char *name, int *num_mem) 532{ 533 size_t len; 534 int i; 535 536 if (gr == NULL) 537 return (0); 538 /* Calculate size of the group. */ 539 len = sizeof(*gr); 540 if (gr->gr_name != NULL) 541 len += strlen(gr->gr_name) + 1; 542 if (gr->gr_passwd != NULL) 543 len += strlen(gr->gr_passwd) + 1; 544 i = 0; 545 if (gr->gr_mem != NULL) { 546 for (; gr->gr_mem[i] != NULL; i++) { 547 len += strlen(gr->gr_mem[i]) + 1; 548 len += sizeof(*gr->gr_mem); 549 } 550 } 551 if (name != NULL) { 552 i++; 553 len += strlen(name) + 1; 554 len += sizeof(*gr->gr_mem); 555 } 556 /* Allow for NULL pointer */ 557 if (i != 0) 558 len += sizeof(*gr->gr_mem); 559 *num_mem = i; 560 return(len); 561} 562 563/* 564 * Scan a line and place it into a group structure. 565 */ 566static bool 567__gr_scan(char *line, struct group *gr) 568{ 569 char *loc; 570 int ndx; 571 572 /* Assign non-member information to structure. */ 573 gr->gr_name = line; 574 if ((loc = strchr(line, ':')) == NULL) 575 return (false); 576 *loc = '\0'; 577 gr->gr_passwd = loc + 1; 578 if (*gr->gr_passwd == ':') 579 *gr->gr_passwd = '\0'; 580 else { 581 if ((loc = strchr(loc + 1, ':')) == NULL) 582 return (false); 583 *loc = '\0'; 584 } 585 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 586 return (false); 587 588 /* Assign member information to structure. */ 589 if ((loc = strchr(loc + 1, ':')) == NULL) 590 return (false); 591 line = loc + 1; 592 gr->gr_mem = NULL; 593 ndx = 0; 594 do { 595 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 596 (ndx + 1)); 597 if (gr->gr_mem == NULL) 598 return (false); 599 600 /* Skip locations without members (i.e., empty string). */ 601 do { 602 gr->gr_mem[ndx] = strsep(&line, ","); 603 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 604 } while (gr->gr_mem[ndx++] != NULL); 605 606 return (true); 607} 608 609/* 610 * Create a struct group from a line. 611 */ 612struct group * 613gr_scan(const char *line) 614{ 615 struct group gr; 616 char *line_copy; 617 struct group *new_gr; 618 619 if ((line_copy = strdup(line)) == NULL) 620 return (NULL); 621 if (!__gr_scan(line_copy, &gr)) { 622 free(line_copy); 623 return (NULL); 624 } 625 new_gr = gr_dup(&gr); 626 free(line_copy); 627 if (gr.gr_mem != NULL) 628 free(gr.gr_mem); 629 630 return (new_gr); 631} 632