gr_util.c revision 244736
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 244736 2012-12-27 14:30:19Z bapt $"); 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 47struct group_storage { 48 struct group gr; 49 char *members[]; 50}; 51 52static int lockfd = -1; 53static char group_dir[PATH_MAX]; 54static char group_file[PATH_MAX]; 55static char tempname[PATH_MAX]; 56static int initialized; 57 58static const char group_line_format[] = "%s:%s:%ju:"; 59 60/* 61 * Initialize statics 62 */ 63int 64gr_init(const char *dir, const char *group) 65{ 66 67 if (dir == NULL) { 68 strcpy(group_dir, _PATH_ETC); 69 } else { 70 if (strlen(dir) >= sizeof(group_dir)) { 71 errno = ENAMETOOLONG; 72 return (-1); 73 } 74 strcpy(group_dir, dir); 75 } 76 77 if (group == NULL) { 78 if (dir == NULL) { 79 strcpy(group_file, _PATH_GROUP); 80 } else if (snprintf(group_file, sizeof(group_file), "%s/group", 81 group_dir) > (int)sizeof(group_file)) { 82 errno = ENAMETOOLONG; 83 return (-1); 84 } 85 } else { 86 if (strlen(group) >= sizeof(group_file)) { 87 errno = ENAMETOOLONG; 88 return (-1); 89 } 90 strcpy(group_file, group); 91 } 92 93 initialized = 1; 94 return (0); 95} 96 97/* 98 * Lock the group file 99 */ 100int 101gr_lock(void) 102{ 103 if (*group_file == '\0') 104 return (-1); 105 106 for (;;) { 107 struct stat st; 108 109 lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK, 0); 110 if (lockfd == -1) { 111 if (errno == EWOULDBLOCK) { 112 errx(1, "the group file is busy"); 113 } else { 114 err(1, "could not lock the group file: "); 115 } 116 } 117 if (fstat(lockfd, &st) == -1) 118 err(1, "fstat() failed: "); 119 if (st.st_nlink != 0) 120 break; 121 close(lockfd); 122 lockfd = -1; 123 } 124 return (lockfd); 125} 126 127/* 128 * Create and open a presmuably safe temp file for editing group data 129 */ 130int 131gr_tmp(int mfd) 132{ 133 char buf[8192]; 134 ssize_t nr; 135 const char *p; 136 int tfd; 137 138 if (*group_file == '\0') 139 return (-1); 140 if ((p = strrchr(group_file, '/'))) 141 ++p; 142 else 143 p = group_file; 144 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX", 145 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) { 146 errno = ENAMETOOLONG; 147 return (-1); 148 } 149 if ((tfd = mkstemp(tempname)) == -1) 150 return (-1); 151 if (mfd != -1) { 152 while ((nr = read(mfd, buf, sizeof(buf))) > 0) 153 if (write(tfd, buf, (size_t)nr) != nr) 154 break; 155 if (nr != 0) { 156 unlink(tempname); 157 *tempname = '\0'; 158 close(tfd); 159 return (-1); 160 } 161 } 162 return (tfd); 163} 164 165/* 166 * Copy the group file from one descriptor to another, replacing, deleting 167 * or adding a single record on the way. 168 */ 169int 170gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr) 171{ 172 char buf[8192], *end, *line, *p, *q, *r, t; 173 struct group *fgr; 174 const struct group *sgr; 175 size_t len; 176 int eof, readlen; 177 178 sgr = gr; 179 if (gr == NULL) { 180 line = NULL; 181 if (old_gr == NULL) 182 return (-1); 183 sgr = old_gr; 184 } else if ((line = gr_make(gr)) == NULL) 185 return (-1); 186 187 eof = 0; 188 len = 0; 189 p = q = end = buf; 190 for (;;) { 191 /* find the end of the current line */ 192 for (p = q; q < end && *q != '\0'; ++q) 193 if (*q == '\n') 194 break; 195 196 /* if we don't have a complete line, fill up the buffer */ 197 if (q >= end) { 198 if (eof) 199 break; 200 if ((size_t)(q - p) >= sizeof(buf)) { 201 warnx("group line too long"); 202 errno = EINVAL; /* hack */ 203 goto err; 204 } 205 if (p < end) { 206 q = memmove(buf, p, end -p); 207 end -= p - buf; 208 } else { 209 p = q = end = buf; 210 } 211 readlen = read(ffd, end, sizeof(buf) - (end -buf)); 212 if (readlen == -1) 213 goto err; 214 else 215 len = (size_t)readlen; 216 if (len == 0 && p == buf) 217 break; 218 end += len; 219 len = end - buf; 220 if (len < (ssize_t)sizeof(buf)) { 221 eof = 1; 222 if (len > 0 && buf[len -1] != '\n') 223 ++len, *end++ = '\n'; 224 } 225 continue; 226 } 227 228 /* is it a blank line or a comment? */ 229 for (r = p; r < q && isspace(*r); ++r) 230 /* nothing */; 231 if (r == q || *r == '#') { 232 /* yep */ 233 if (write(tfd, p, q -p + 1) != q - p + 1) 234 goto err; 235 ++q; 236 continue; 237 } 238 239 /* is it the one we're looking for? */ 240 241 t = *q; 242 *q = '\0'; 243 244 fgr = gr_scan(r); 245 246 /* fgr is either a struct group for the current line, 247 * or NULL if the line is malformed. 248 */ 249 250 *q = t; 251 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) { 252 /* nope */ 253 if (fgr != NULL) 254 free(fgr); 255 if (write(tfd, p, q - p + 1) != q - p + 1) 256 goto err; 257 ++q; 258 continue; 259 } 260 if (old_gr && !gr_equal(fgr, old_gr)) { 261 warnx("entry inconsistent"); 262 free(fgr); 263 errno = EINVAL; /* hack */ 264 goto err; 265 } 266 free(fgr); 267 268 /* it is, replace or remove it */ 269 if (line != NULL) { 270 len = strlen(line); 271 if (write(tfd, line, len) != (int) len) 272 goto err; 273 } else { 274 /* when removed, avoid the \n */ 275 q++; 276 } 277 /* we're done, just copy the rest over */ 278 for (;;) { 279 if (write(tfd, q, end - q) != end - q) 280 goto err; 281 q = buf; 282 readlen = read(ffd, buf, sizeof(buf)); 283 if (readlen == 0) 284 break; 285 else 286 len = (size_t)readlen; 287 if (readlen == -1) 288 goto err; 289 end = buf + len; 290 } 291 goto done; 292 } 293 294 /* if we got here, we didn't find the old entry */ 295 if (line == NULL) { 296 errno = ENOENT; 297 goto err; 298 } 299 len = strlen(line); 300 if ((size_t)write(tfd, line, len) != len || 301 write(tfd, "\n", 1) != 1) 302 goto err; 303 done: 304 if (line != NULL) 305 free(line); 306 return (0); 307 err: 308 if (line != NULL) 309 free(line); 310 return (-1); 311} 312 313/* 314 * Regenerate the group file 315 */ 316int 317gr_mkdb(void) 318{ 319 if (chmod(tempname, 0644) != 0) 320 return (-1); 321 322 return (rename(tempname, group_file)); 323} 324 325/* 326 * Clean up. Preserver errno for the caller's convenience. 327 */ 328void 329gr_fini(void) 330{ 331 int serrno; 332 333 if (!initialized) 334 return; 335 initialized = 0; 336 serrno = errno; 337 if (*tempname != '\0') { 338 unlink(tempname); 339 *tempname = '\0'; 340 } 341 if (lockfd != -1) 342 close(lockfd); 343 errno = serrno; 344} 345 346/* 347 * Compares two struct group's. 348 */ 349int 350gr_equal(const struct group *gr1, const struct group *gr2) 351{ 352 int gr1_ndx; 353 int gr2_ndx; 354 bool found; 355 356 /* Check that the non-member information is the same. */ 357 if (gr1->gr_name == NULL || gr2->gr_name == NULL) { 358 if (gr1->gr_name != gr2->gr_name) 359 return (false); 360 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0) 361 return (false); 362 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) { 363 if (gr1->gr_passwd != gr2->gr_passwd) 364 return (false); 365 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0) 366 return (false); 367 if (gr1->gr_gid != gr2->gr_gid) 368 return (false); 369 370 /* Check all members in both groups. */ 371 if (gr1->gr_mem == NULL || gr2->gr_mem == NULL) { 372 if (gr1->gr_mem != gr2->gr_mem) 373 return (false); 374 } else { 375 for (found = false, gr1_ndx = 0; gr1->gr_mem[gr1_ndx] != NULL; 376 gr1_ndx++) { 377 for (gr2_ndx = 0; gr2->gr_mem[gr2_ndx] != NULL; 378 gr2_ndx++) 379 if (strcmp(gr1->gr_mem[gr1_ndx], 380 gr2->gr_mem[gr2_ndx]) == 0) { 381 found = true; 382 break; 383 } 384 if (!found) 385 return (false); 386 } 387 388 /* Check that group2 does not have more members than group1. */ 389 if (gr2->gr_mem[gr1_ndx] != NULL) 390 return (false); 391 } 392 393 return (true); 394} 395 396/* 397 * Make a group line out of a struct group. 398 */ 399char * 400gr_make(const struct group *gr) 401{ 402 char *line; 403 size_t line_size; 404 int ndx; 405 406 /* Calculate the length of the group line. */ 407 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name, 408 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1; 409 if (gr->gr_mem != NULL) { 410 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) 411 line_size += strlen(gr->gr_mem[ndx]) + 1; 412 if (ndx > 0) 413 line_size--; 414 } 415 416 /* Create the group line and fill it. */ 417 if ((line = malloc(line_size)) == NULL) 418 return (NULL); 419 snprintf(line, line_size, group_line_format, gr->gr_name, gr->gr_passwd, 420 (uintmax_t)gr->gr_gid); 421 if (gr->gr_mem != NULL) 422 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) { 423 strcat(line, gr->gr_mem[ndx]); 424 if (gr->gr_mem[ndx + 1] != NULL) 425 strcat(line, ","); 426 } 427 428 return (line); 429} 430 431/* 432 * Duplicate a struct group. 433 */ 434struct group * 435gr_dup(const struct group *gr) 436{ 437 char *dst; 438 size_t len; 439 struct group_storage *gs; 440 int ndx; 441 int num_mem; 442 443 /* Calculate size of the group. */ 444 len = sizeof(*gs); 445 if (gr->gr_name != NULL) 446 len += strlen(gr->gr_name) + 1; 447 if (gr->gr_passwd != NULL) 448 len += strlen(gr->gr_passwd) + 1; 449 if (gr->gr_mem != NULL) { 450 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) 451 len += strlen(gr->gr_mem[num_mem]) + 1; 452 len += (num_mem + 1) * sizeof(*gr->gr_mem); 453 } else 454 num_mem = -1; 455 456 /* Create new group and copy old group into it. */ 457 if ((gs = calloc(1, len)) == NULL) 458 return (NULL); 459 dst = (char *)&gs->members[num_mem + 1]; 460 if (gr->gr_name != NULL) { 461 gs->gr.gr_name = dst; 462 dst = stpcpy(gs->gr.gr_name, gr->gr_name) + 1; 463 } 464 if (gr->gr_passwd != NULL) { 465 gs->gr.gr_passwd = dst; 466 dst = stpcpy(gs->gr.gr_passwd, gr->gr_passwd) + 1; 467 } 468 gs->gr.gr_gid = gr->gr_gid; 469 if (gr->gr_mem != NULL) { 470 gs->gr.gr_mem = gs->members; 471 for (ndx = 0; ndx < num_mem; ndx++) { 472 gs->gr.gr_mem[ndx] = dst; 473 dst = stpcpy(gs->gr.gr_mem[ndx], gr->gr_mem[ndx]) + 1; 474 } 475 gs->gr.gr_mem[ndx] = NULL; 476 } 477 478 return (&gs->gr); 479} 480 481/* 482 * Add a new member name to a struct group. 483 */ 484struct group * 485gr_add(struct group *gr, const char *newmember) 486{ 487 size_t mlen; 488 int num_mem=0; 489 char **members; 490 struct group *newgr; 491 492 if (newmember == NULL) 493 return(gr_dup(gr)); 494 495 if (gr->gr_mem != NULL) { 496 for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) { 497 if (strcmp(gr->gr_mem[num_mem], newmember) == 0) { 498 errno = EEXIST; 499 return (NULL); 500 } 501 } 502 } 503 /* Allocate enough for current pointers + 1 more and NULL marker */ 504 mlen = (num_mem + 2) * sizeof(*gr->gr_mem); 505 if ((members = calloc(1, mlen )) == NULL) { 506 errno = ENOMEM; 507 return (NULL); 508 } 509 memcpy(members, gr->gr_mem, num_mem * sizeof(*gr->gr_mem)); 510 members[num_mem++] = (char *)newmember; 511 members[num_mem] = NULL; 512 gr->gr_mem = members; 513 newgr = gr_dup(gr); 514 if (newgr == NULL) 515 errno = ENOMEM; 516 517 free(members); 518 return (newgr); 519} 520 521/* 522 * Scan a line and place it into a group structure. 523 */ 524static bool 525__gr_scan(char *line, struct group *gr) 526{ 527 char *loc; 528 int ndx; 529 530 /* Assign non-member information to structure. */ 531 gr->gr_name = line; 532 if ((loc = strchr(line, ':')) == NULL) 533 return (false); 534 *loc = '\0'; 535 gr->gr_passwd = loc + 1; 536 if (*gr->gr_passwd == ':') 537 *gr->gr_passwd = '\0'; 538 else { 539 if ((loc = strchr(loc + 1, ':')) == NULL) 540 return (false); 541 *loc = '\0'; 542 } 543 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1) 544 return (false); 545 546 /* Assign member information to structure. */ 547 if ((loc = strchr(loc + 1, ':')) == NULL) 548 return (false); 549 line = loc + 1; 550 gr->gr_mem = NULL; 551 ndx = 0; 552 do { 553 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) * 554 (ndx + 1)); 555 if (gr->gr_mem == NULL) 556 return (false); 557 558 /* Skip locations without members (i.e., empty string). */ 559 do { 560 gr->gr_mem[ndx] = strsep(&line, ","); 561 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0'); 562 } while (gr->gr_mem[ndx++] != NULL); 563 564 return (true); 565} 566 567/* 568 * Create a struct group from a line. 569 */ 570struct group * 571gr_scan(const char *line) 572{ 573 struct group gr; 574 char *line_copy; 575 struct group *new_gr; 576 577 if ((line_copy = strdup(line)) == NULL) 578 return (NULL); 579 if (!__gr_scan(line_copy, &gr)) { 580 free(line_copy); 581 return (NULL); 582 } 583 new_gr = gr_dup(&gr); 584 free(line_copy); 585 if (gr.gr_mem != NULL) 586 free(gr.gr_mem); 587 588 return (new_gr); 589} 590