chmod/chmod_acl.c

   1 /*
   2  * Copyright (c) 1989, 1993, 1994
   3  *      The Regents of the University of California.  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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33 #include <err.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <sys/types.h>
  38 #include <unistd.h>
  39 #include <errno.h>
  40 #include <fcntl.h>
  41 #include <sys/stat.h>
  42
  43 #include <membership.h>
  44 #include "chmod_acl.h"
  45
  46 extern void usage(void);
  47
  48 #ifdef __APPLE__
  49 static struct {
  50         acl_perm_t      perm;
  51         char            *name;
  52         int             flags;
  53 #define ACL_PERM_DIR    (1<<0)
  54 #define ACL_PERM_FILE   (1<<1)
  55 } acl_perms[] = {
  56         {ACL_READ_DATA,         "read",         ACL_PERM_FILE},
  57         {ACL_LIST_DIRECTORY,    "list",         ACL_PERM_DIR},
  58         {ACL_WRITE_DATA,        "write",        ACL_PERM_FILE},
  59         {ACL_ADD_FILE,          "add_file",     ACL_PERM_DIR},
  60         {ACL_EXECUTE,           "execute",      ACL_PERM_FILE},
  61         {ACL_SEARCH,            "search",       ACL_PERM_DIR},
  62         {ACL_DELETE,            "delete",       ACL_PERM_FILE | ACL_PERM_DIR},
  63         {ACL_APPEND_DATA,       "append",       ACL_PERM_FILE},
  64         {ACL_ADD_SUBDIRECTORY,  "add_subdirectory", ACL_PERM_DIR},
  65         {ACL_DELETE_CHILD,      "delete_child", ACL_PERM_DIR},
  66         {ACL_READ_ATTRIBUTES,   "readattr",     ACL_PERM_FILE | ACL_PERM_DIR},
  67         {ACL_WRITE_ATTRIBUTES,  "writeattr",    ACL_PERM_FILE | ACL_PERM_DIR},
  68         {ACL_READ_EXTATTRIBUTES, "readextattr", ACL_PERM_FILE | ACL_PERM_DIR},
  69         {ACL_WRITE_EXTATTRIBUTES, "writeextattr", ACL_PERM_FILE | ACL_PERM_DIR},
  70         {ACL_READ_SECURITY,     "readsecurity", ACL_PERM_FILE | ACL_PERM_DIR},
  71         {ACL_WRITE_SECURITY,    "writesecurity", ACL_PERM_FILE | ACL_PERM_DIR},
  72         {ACL_CHANGE_OWNER,      "chown",        ACL_PERM_FILE | ACL_PERM_DIR},
  73         {0, NULL, 0}
  74 };
  75
  76 static struct {
  77         acl_flag_t      flag;
  78         char            *name;
  79         int             flags;
  80 } acl_flags[] = {
  81         {ACL_ENTRY_INHERITED,           "inherited",            ACL_PERM_FILE | ACL_PERM_DIR},
  82         {ACL_ENTRY_FILE_INHERIT,        "file_inherit",         ACL_PERM_DIR},
  83         {ACL_ENTRY_DIRECTORY_INHERIT,   "directory_inherit",    ACL_PERM_DIR},
  84         {ACL_ENTRY_LIMIT_INHERIT,       "limit_inherit",        ACL_PERM_FILE | ACL_PERM_DIR},
  85         {ACL_ENTRY_ONLY_INHERIT,        "only_inherit",         ACL_PERM_DIR},
  86         {0, NULL, 0}
  87 };
  88
  89 /* TBD - Many of these routines could potentially be considered for
  90  * inclusion in a library. If that is done, either avoid use of "err"
  91  * and implement a better fall-through strategy in case of errors,
  92  * or use err_set_exit() and make various structures globals.
  93  */
  94
  95 #define NAME_USER   (1)
  96 #define NAME_GROUP  (2)
  97 #define NAME_EITHER (NAME_USER | NAME_GROUP)
  98
  99 /* Perform a name to uuid mapping - calls through to memberd */
 100
 101 uuid_t *
 102 name_to_uuid(char *tok, int nametype) {
 103         struct passwd *tpass = NULL;
 104         struct group *tgrp = NULL;
 105         uuid_t *entryg = NULL;
 106
 107         if ((entryg = (uuid_t *) calloc(1,sizeof(uuid_t))) == NULL)
 108                 err(1, "Unable to allocate a uuid");
 109
 110         if (nametype & NAME_USER)
 111                 tpass = getpwnam(tok);
 112
 113         if (NULL == tpass && (nametype & NAME_GROUP))
 114                 tgrp = getgrnam(tok);
 115
 116         if (tpass) {
 117                 if (0 != mbr_uid_to_uuid(tpass->pw_uid, *entryg)) {
 118                         errx(1, "mbr_uid_to_uuid(): Unable to translate uid %d", tpass->pw_uid);
 119                 }
 120         } else if (tgrp) {
 121                 if (0 != mbr_gid_to_uuid(tgrp->gr_gid, *entryg)) {
 122                         errx(1, "mbr_gid_to_uuid(): Unable to translate gid %d", tgrp->gr_gid);
 123                 }
 124         } else {
 125                 errx(1, "Unable to translate '%s' to a UID/GID", tok);
 126         }
 127         return entryg;
 128 }
 129
 130 /* Convert an acl entry in string form to an acl_entry_t */
 131 int
 132 parse_entry(char *entrybuf, acl_entry_t newent) {
 133         char *tok;
 134         char *pebuf;
 135         uuid_t *entryg;
 136
 137         acl_tag_t       tag;
 138         acl_permset_t   perms;
 139         acl_flagset_t   flags;
 140         unsigned permcount = 0;
 141         unsigned pindex = 0;
 142         char *delimiter = " ";
 143         int nametype = NAME_EITHER;
 144
 145         acl_get_permset(newent, &perms);
 146         acl_get_flagset_np(newent, &flags);
 147
 148         pebuf = entrybuf;
 149
 150         if (0 == strncmp(entrybuf, "user:", 5)) {
 151                 nametype = NAME_USER;
 152                 pebuf += 5;
 153         } else if (0 == strncmp(entrybuf, "group:", 6)) {
 154                 nametype = NAME_GROUP;
 155                 pebuf += 6;
 156         }
 157
 158         if (strchr(pebuf, ':')) /* User/Group names can have spaces */
 159                 delimiter = ":";
 160         tok = strsep(&pebuf, delimiter);
 161
 162         if ((tok == NULL) || *tok == '\0') {
 163                 errx(1, "Invalid entry format -- expected user or group name");
 164         }
 165
 166         /* parse the name into a qualifier */
 167         entryg = name_to_uuid(tok, nametype);
 168
 169         tok = strsep(&pebuf, ": "); /* Stick with delimiter? */
 170         if ((tok == NULL) || *tok == '\0') {
 171                 errx(1, "Invalid entry format -- expected allow or deny");
 172         }
 173
 174         /* is the verb 'allow' or 'deny'? */
 175         if (!strcmp(tok, "allow")) {
 176                 tag = ACL_EXTENDED_ALLOW;
 177         } else if (!strcmp(tok, "deny")) {
 178                 tag = ACL_EXTENDED_DENY;
 179         } else {
 180                 errx(1, "Unknown tag type '%s'", tok);
 181         }
 182
 183         /* parse permissions */
 184         for (; (tok = strsep(&pebuf, ",")) != NULL;) {
 185                 if (*tok != '\0') {
 186                         /* is it a permission? */
 187                         for (pindex = 0; acl_perms[pindex].name != NULL; pindex++) {
 188                                 if (!strcmp(acl_perms[pindex].name, tok)) {
 189                                         /* got one */
 190                                         acl_add_perm(perms, acl_perms[pindex].perm);
 191                                         permcount++;
 192                                         goto found;
 193                                 }
 194                         }
 195                         /* is it a flag? */
 196                         for (pindex = 0; acl_flags[pindex].name != NULL; pindex++) {
 197                                 if (!strcmp(acl_flags[pindex].name, tok)) {
 198                                         /* got one */
 199                                         acl_add_flag_np(flags, acl_flags[pindex].flag);
 200                                         permcount++;
 201                                         goto found;
 202                                 }
 203                         }
 204                         errx(1,"Invalid permission type '%s'", tok);
 205                 found:
 206                         continue;
 207                 }
 208         }
 209         if (0 == permcount) {
 210                 errx(1, "No permissions specified");
 211         }
 212         acl_set_tag_type(newent, tag);
 213         acl_set_qualifier(newent, entryg);
 214         acl_set_permset(newent, perms);
 215         acl_set_flagset_np(newent, flags);
 216         free(entryg);
 217
 218         return(0);
 219 }
 220
 221 /* Convert one or more acl entries in string form to an acl_t */
 222 acl_t
 223 parse_acl_entries(const char *input) {
 224         acl_t acl_input;
 225         acl_entry_t newent;
 226         char *inbuf;
 227         char *oinbuf;
 228
 229         char **bufp, *entryv[ACL_MAX_ENTRIES];
 230 #if 0
 231 /* XXX acl_from_text(), when implemented, will presumably use the canonical
 232  * text representation format, which is what chmod should be using
 233  * We may need to add an entry number to the input
 234  */
 235         /* Translate the user supplied ACL entry */
 236         /* acl_input = acl_from_text(input); */
 237 #else
 238         inbuf = malloc(MAX_ACL_TEXT_SIZE);
 239
 240         if (inbuf == NULL)
 241                 err(1, "malloc() failed");
 242         strncpy(inbuf, input, MAX_ACL_TEXT_SIZE);
 243         inbuf[MAX_ACL_TEXT_SIZE - 1] = '\0';
 244
 245         if ((acl_input = acl_init(1)) == NULL)
 246                 err(1, "acl_init() failed");
 247
 248         oinbuf = inbuf;
 249
 250         for (bufp = entryv; (*bufp = strsep(&oinbuf, "\n")) != NULL;)
 251                 if (**bufp != '\0') {
 252                         if (0 != acl_create_entry(&acl_input, &newent))
 253                                 err(1, "acl_create_entry() failed");
 254                         if (0 != parse_entry(*bufp, newent)) {
 255                                 errx(1, "Failed parsing entry '%s'", *bufp);
 256                         }
 257                         if (++bufp >= &entryv[ACL_MAX_ENTRIES - 1]) {
 258                                 errx(1, "Too many entries");
 259                         }
 260                 }
 261
 262         free(inbuf);
 263         return acl_input;
 264 #endif  /* #if 0 */
 265 }
 266
 267 /* XXX No Libc support for inherited entries and generation determination yet */
 268 unsigned
 269 get_inheritance_level(acl_entry_t entry) {
 270 /* XXX to be implemented */
 271         return 1;
 272 }
 273
 274 /* Determine a "score" for an acl entry. The entry scores higher if it's
 275  * tagged ACL_EXTENDED_DENY, and non-inherited entries are ranked higher
 276  * than inherited entries.
 277  */
 278
 279 int
 280 score_acl_entry(acl_entry_t entry) {
 281
 282         acl_tag_t       tag;
 283         acl_flagset_t   flags;
 284         acl_permset_t   perms;
 285
 286         int score = 0;
 287
 288         if (entry == NULL)
 289                 return (MINIMUM_TIER);
 290
 291         if (acl_get_tag_type(entry, &tag) != 0) {
 292                 err(1, "Malformed ACL entry, no tag present");
 293         }
 294         if (acl_get_flagset_np(entry, &flags) != 0){
 295                 err(1, "Unable to obtain flagset");
 296         }
 297         if (acl_get_permset(entry, &perms) != 0)
 298                 err(1, "Malformed ACL entry, no permset present");
 299
 300         switch(tag) {
 301         case ACL_EXTENDED_ALLOW:
 302                 break;
 303         case ACL_EXTENDED_DENY:
 304                 score++;
 305                 break;
 306         default:
 307                 errx(1, "Unknown tag type %d present in ACL entry", tag);
 308                 /* NOTREACHED */
 309         }
 310
 311         if (acl_get_flag_np(flags, ACL_ENTRY_INHERITED))
 312                 score += get_inheritance_level(entry) * INHERITANCE_TIER;
 313
 314         return score;
 315 }
 316
 317 int
 318 compare_acl_qualifiers(uuid_t *qa, uuid_t *qb) {
 319         return bcmp(qa, qb, sizeof(uuid_t));
 320 }
 321
 322 /* Compare two ACL permsets.
 323  *  Returns :
 324  *  MATCH_SUBSET if bperms is a subset of aperms
 325  *  MATCH_SUPERSET if bperms is a superset of aperms
 326  *  MATCH_PARTIAL if the two permsets have a common subset
 327  *  MATCH_EXACT if the two permsets are identical
 328  *  MATCH_NONE if they are disjoint
 329  */
 330
 331 int
 332 compare_acl_permsets(acl_permset_t aperms, acl_permset_t bperms)
 333 {
 334         int i;
 335 /* TBD Implement other match levels as needed */
 336         for (i = 0; acl_perms[i].name != NULL; i++) {
 337                 if (acl_get_perm_np(aperms, acl_perms[i].perm) !=
 338                     acl_get_perm_np(bperms, acl_perms[i].perm))
 339                         return MATCH_NONE;
 340         }
 341         return MATCH_EXACT;
 342 }
 343
 344 static int
 345 compare_acl_flagsets(acl_flagset_t aflags, acl_flagset_t bflags)
 346 {
 347         int i;
 348 /* TBD Implement other match levels as needed */
 349         for (i = 0; acl_flags[i].name != NULL; i++) {
 350                 if (acl_get_flag_np(aflags, acl_flags[i].flag) !=
 351                     acl_get_flag_np(bflags, acl_flags[i].flag))
 352                         return MATCH_NONE;
 353         }
 354         return MATCH_EXACT;
 355 }
 356
 357 /* Compares two ACL entries for equality */
 358 int
 359 compare_acl_entries(acl_entry_t a, acl_entry_t b)
 360 {
 361         acl_tag_t atag, btag;
 362         acl_permset_t aperms, bperms;
 363         acl_flagset_t aflags, bflags;
 364         int pcmp = 0, fcmp = 0;
 365         void *aqual, *bqual;
 366
 367         aqual = acl_get_qualifier(a);
 368         bqual = acl_get_qualifier(b);
 369
 370         int compare = compare_acl_qualifiers(aqual, bqual);
 371         acl_free(aqual);
 372         acl_free(bqual);
 373
 374         if (compare != 0)
 375                 return MATCH_NONE;
 376
 377         if (0 != acl_get_tag_type(a, &atag))
 378                 err(1, "No tag type present in entry");
 379         if (0!= acl_get_tag_type(b, &btag))
 380                 err(1, "No tag type present in entry");
 381
 382         if (atag != btag)
 383                 return MATCH_NONE;
 384
 385         if ((acl_get_permset(a, &aperms) != 0) ||
 386             (acl_get_flagset_np(a, &aflags) != 0) ||
 387             (acl_get_permset(b, &bperms) != 0) ||
 388             (acl_get_flagset_np(b, &bflags) != 0))
 389                 err(1, "error fetching permissions");
 390
 391         pcmp = compare_acl_permsets(aperms, bperms);
 392         fcmp = compare_acl_flagsets(aflags, bflags);
 393
 394         if ((pcmp == MATCH_NONE) || (fcmp == MATCH_NONE))
 395                 return(MATCH_PARTIAL);
 396         else
 397                 return(MATCH_EXACT);
 398 }
 399
 400 /* Verify that an ACL is in canonical order. Currently, the canonical
 401  * form is:
 402  * local deny
 403  * local allow
 404  * inherited deny (parent)
 405  * inherited allow (parent)
 406  * inherited deny (grandparent)
 407  * inherited allow (grandparent)
 408  * ...
 409  */
 410 unsigned int
 411 is_canonical(acl_t acl) {
 412
 413         unsigned aindex;
 414         acl_entry_t entry;
 415         int score = 0, next_score = 0;
 416
 417 /* XXX - is a zero entry ACL in canonical form? */
 418         if (0 != acl_get_entry(acl, ACL_FIRST_ENTRY, &entry))
 419                 return 1;
 420
 421         score = score_acl_entry(entry);
 422
 423         for (aindex = 0; acl_get_entry(acl, ACL_NEXT_ENTRY, &entry) == 0;
 424              aindex++)  {
 425                 if (score < (next_score = score_acl_entry(entry)))
 426                         return 0;
 427                 score = next_score;
 428         }
 429         return 1;
 430 }
 431
 432
 433 /* Iterate through an ACL, and find the canonical position for the
 434  * specified entry
 435  */
 436 unsigned int
 437 find_canonical_position(acl_t acl, acl_entry_t modifier) {
 438
 439         acl_entry_t entry;
 440         int mscore = 0;
 441         unsigned mpos = 0;
 442
 443         /* Check if there's an entry with the same qualifier
 444          * and tag type; if not, find the appropriate slot
 445          * for the score.
 446          */
 447
 448         if (0 != acl_get_entry(acl, ACL_FIRST_ENTRY, &entry))
 449                 return 0;
 450
 451         mscore = score_acl_entry(modifier);
 452
 453         while (mscore < score_acl_entry(entry)) {
 454
 455                 mpos++;
 456
 457                if (0 != acl_get_entry(acl, ACL_NEXT_ENTRY, &entry))
 458                        break;
 459
 460                }
 461         return mpos;
 462 }
 463
 464 int canonicalize_acl_entries(acl_t acl);
 465
 466 /* For a given acl_entry_t "modifier", find the first exact or
 467  * partially matching entry from the specified acl_t acl
 468  */
 469
 470 int
 471 find_matching_entry (acl_t acl, acl_entry_t modifier, acl_entry_t *rentryp,
 472                      unsigned match_inherited) {
 473
 474         acl_entry_t entry = NULL;
 475
 476         unsigned aindex;
 477         int cmp, fcmp = MATCH_NONE;
 478
 479         for (aindex = 0;
 480              acl_get_entry(acl, entry == NULL ? ACL_FIRST_ENTRY :
 481                            ACL_NEXT_ENTRY, &entry) == 0;
 482              aindex++)  {
 483                 cmp = compare_acl_entries(entry, modifier);
 484                 if ((cmp == MATCH_EXACT) || (cmp == MATCH_PARTIAL)) {
 485                         if (match_inherited) {
 486                                 acl_flagset_t eflags, mflags;
 487
 488                                 if (0 != acl_get_flagset_np(modifier, &mflags))
 489                                         err(1, "Unable to get flagset");
 490
 491                                 if (0 != acl_get_flagset_np(entry, &eflags))
 492                                         err(1, "Unable to get flagset");
 493
 494                                 if (compare_acl_flagsets(mflags, eflags) == MATCH_EXACT) {
 495                                         *rentryp = entry;
 496                                         fcmp = cmp;
 497                                 }
 498                         }
 499                         else {
 500                                 *rentryp = entry;
 501                                 fcmp = cmp;
 502                         }
 503                 }
 504                 if (fcmp == MATCH_EXACT)
 505                         break;
 506         }
 507         return fcmp;
 508 }
 509
 510 /* Remove all perms specified in modifier from rentry*/
 511 int
 512 subtract_from_entry(acl_entry_t rentry, acl_entry_t  modifier, int* valid_perms)
 513 {
 514         acl_permset_t rperms, mperms;
 515         acl_flagset_t rflags, mflags;
 516         if (valid_perms)
 517                 *valid_perms = 0;
 518         int i;
 519
 520         if ((acl_get_permset(rentry, &rperms) != 0) ||
 521             (acl_get_flagset_np(rentry, &rflags) != 0) ||
 522             (acl_get_permset(modifier, &mperms) != 0) ||
 523             (acl_get_flagset_np(modifier, &mflags) != 0))
 524                 err(1, "error computing ACL modification");
 525
 526         for (i = 0; acl_perms[i].name != NULL; i++) {
 527                 if (acl_get_perm_np(mperms, acl_perms[i].perm))
 528                         acl_delete_perm(rperms, acl_perms[i].perm);
 529                 else if (valid_perms && acl_get_perm_np(rperms, acl_perms[i].perm))
 530                         (*valid_perms)++;
 531         }
 532         for (i = 0; acl_flags[i].name != NULL; i++) {
 533                 if (acl_get_flag_np(mflags, acl_flags[i].flag))
 534                         acl_delete_flag_np(rflags, acl_flags[i].flag);
 535         }
 536         acl_set_permset(rentry, rperms);
 537         acl_set_flagset_np(rentry, rflags);
 538         return 0;
 539 }
 540 /* Add the perms specified in modifier to rentry */
 541 static int
 542 merge_entry_perms(acl_entry_t rentry, acl_entry_t  modifier)
 543 {
 544         acl_permset_t rperms, mperms;
 545         acl_flagset_t rflags, mflags;
 546         int i;
 547
 548         if ((acl_get_permset(rentry, &rperms) != 0) ||
 549             (acl_get_flagset_np(rentry, &rflags) != 0) ||
 550             (acl_get_permset(modifier, &mperms) != 0) ||
 551             (acl_get_flagset_np(modifier, &mflags) != 0))
 552                 err(1, "error computing ACL modification");
 553
 554         for (i = 0; acl_perms[i].name != NULL; i++) {
 555                 if (acl_get_perm_np(mperms, acl_perms[i].perm))
 556                         acl_add_perm(rperms, acl_perms[i].perm);
 557         }
 558         for (i = 0; acl_flags[i].name != NULL; i++) {
 559                 if (acl_get_flag_np(mflags, acl_flags[i].flag))
 560                         acl_add_flag_np(rflags, acl_flags[i].flag);
 561         }
 562         acl_set_permset(rentry, rperms);
 563         acl_set_flagset_np(rentry, rflags);
 564         return 0;
 565 }
 566
 567 int
 568 modify_acl(acl_t *oaclp, acl_entry_t modifier, unsigned int optflags,
 569            int position, int inheritance_level,
 570            unsigned flag_new_acl, const char* path) {
 571
 572         unsigned cpos = 0;
 573         acl_entry_t newent = NULL;
 574         int dmatch = 0;
 575         acl_entry_t rentry = NULL;
 576         unsigned retval = 0;
 577         acl_t oacl = *oaclp;
 578
 579 /* Add the inherited flag if requested by the user*/
 580         if (modifier && (optflags & ACL_INHERIT_FLAG)) {
 581                 acl_flagset_t mflags;
 582
 583                 acl_get_flagset_np(modifier, &mflags);
 584                 acl_add_flag_np(mflags, ACL_ENTRY_INHERITED);
 585                 acl_set_flagset_np(modifier, mflags);
 586         }
 587
 588         if (optflags & ACL_SET_FLAG) {
 589                 if (position != -1) {
 590                         if (0 != acl_create_entry_np(&oacl, &newent, position))
 591                                 err(1, "acl_create_entry() failed");
 592                         acl_copy_entry(newent, modifier);
 593                 } else {
 594 /* If an entry exists, add the new permissions to it, else add an
 595  * entry in the canonical position.
 596  */
 597
 598 /* First, check for a matching entry - if one exists, merge flags */
 599                         dmatch = find_matching_entry(oacl, modifier, &rentry, 1);
 600
 601                         if (dmatch != MATCH_NONE) {
 602                                 if (dmatch == MATCH_EXACT)
 603 /* Nothing to be done */
 604                                         goto ma_exit;
 605
 606                                 if (dmatch == MATCH_PARTIAL) {
 607                                         merge_entry_perms(rentry, modifier);
 608                                         goto ma_exit;
 609                                 }
 610                         }
 611 /* Insert the entry in canonical order */
 612                         cpos = find_canonical_position(oacl, modifier);
 613                         if (0!= acl_create_entry_np(&oacl, &newent, cpos))
 614                                 err(1, "acl_create_entry() failed");
 615                         acl_copy_entry(newent, modifier);
 616                 }
 617         } else if (optflags & ACL_DELETE_FLAG) {
 618                 if (flag_new_acl) {
 619                         warnx("No ACL present '%s'", path);
 620                         retval = 1;
 621                 } else if (position != -1 ) {
 622                         if (0 != acl_get_entry(oacl, position, &rentry)) {
 623                                 warnx("Invalid entry number '%s'", path);
 624                                 retval = 1;
 625                         } else {
 626                                 acl_delete_entry(oacl, rentry);
 627                         }
 628                 } else {
 629                         unsigned match_found = 0, aindex;
 630                         for (aindex = 0;
 631                              acl_get_entry(oacl, rentry == NULL ?
 632                                            ACL_FIRST_ENTRY :
 633                                            ACL_NEXT_ENTRY, &rentry) == 0;
 634                              aindex++)  {
 635                                 unsigned cmp;
 636                                 cmp = compare_acl_entries(rentry, modifier);
 637                                 if ((cmp == MATCH_EXACT) ||
 638                                     (cmp == MATCH_PARTIAL)) {
 639                                         match_found++;
 640                                         if (cmp == MATCH_EXACT)
 641                                                 acl_delete_entry(oacl, rentry);
 642                                         else {
 643                                                 int valid_perms;
 644 /* In the event of a partial match, remove the specified perms from the
 645  * entry */
 646                                                 subtract_from_entry(rentry, modifier, &valid_perms);
 647                                                 /* if no perms survived then delete the entry */
 648                                                 if (valid_perms == 0)
 649                                                         acl_delete_entry(oacl, rentry);
 650                                         }
 651                                 }
 652                         }
 653                         if (0 == match_found) {
 654                                 warnx("Entry not found when attempting delete '%s'",path);
 655                                 retval = 1;
 656                         }
 657                 }
 658         } else if (optflags & ACL_REWRITE_FLAG) {
 659                 acl_entry_t rentry;
 660
 661                 if (-1 == position) {
 662                         usage();
 663                 }
 664                 if (0 == flag_new_acl) {
 665                         if (0 != acl_get_entry(oacl, position,
 666                                                &rentry))
 667                                 err(1, "Invalid entry number '%s'", path);
 668
 669                         if (0 != acl_delete_entry(oacl, rentry))
 670                                 err(1, "Unable to delete entry '%s'", path);
 671                 }
 672                 if (0!= acl_create_entry_np(&oacl, &newent, position))
 673                         err(1, "acl_create_entry() failed");
 674                 acl_copy_entry(newent, modifier);
 675         }
 676 ma_exit:
 677         *oaclp = oacl;
 678         return retval;
 679 }
 680
 681 int
 682 modify_file_acl(unsigned int optflags, const char *path, acl_t modifier, int position, int inheritance_level, int follow) {
 683
 684         acl_t oacl = NULL;
 685         unsigned aindex  = 0, flag_new_acl = 0;
 686         acl_entry_t newent = NULL;
 687         acl_entry_t entry = NULL;
 688         unsigned retval = 0 ;
 689
 690         extern int fflag;
 691
 692 /* XXX acl_get_file() returns a zero entry ACL if an ACL was previously
 693  * associated with the file, and has had its entries removed.
 694  * However, POSIX 1003.1e states that a zero entry ACL should be
 695  * returned if the caller asks for ACL_TYPE_DEFAULT, and no ACL is
 696  * associated with the path; it
 697  * does not specifically state that a request for ACL_TYPE_EXTENDED
 698  * should not return a zero entry ACL, however.
 699  */
 700
 701 /* Determine if we've been given a zero entry ACL, or create an ACL if
 702  * none exists. There are some issues to consider here: Should we create
 703  * a zero-entry ACL for a delete or check canonicity operation?
 704  */
 705
 706         if (path == NULL)
 707                 usage();
 708
 709         if (optflags & ACL_CLEAR_FLAG) {
 710                 filesec_t fsec = filesec_init();
 711                 if (fsec == NULL)
 712                         err(1, "filesec_init() failed");
 713                 if (filesec_set_property(fsec, FILESEC_ACL,
 714                                          _FILESEC_REMOVE_ACL) != 0)
 715                         err(1, "filesec_set_property() failed");
 716                 if (chmodx_np(path, fsec) != 0) {
 717                         if (!fflag)
 718                                 warn("Failed to clear ACL on file %s", path);
 719                         retval = 1;
 720                 } else
 721                         retval = 0;
 722                 filesec_free(fsec);
 723                 return (retval);
 724         }
 725
 726         if (optflags & ACL_FROM_STDIN) {
 727                 oacl = acl_dup(modifier);
 728         } else {
 729                 if (follow) {
 730                         oacl = acl_get_file(path, ACL_TYPE_EXTENDED);
 731                 } else {
 732                         int fd = open(path, O_SYMLINK);
 733                         if (fd != -1) {
 734                                 oacl = acl_get_fd_np(fd, ACL_TYPE_EXTENDED);
 735                                 close(fd);
 736                         }
 737                 }
 738                 if ((oacl == NULL) ||
 739                     (acl_get_entry(oacl,ACL_FIRST_ENTRY, &newent) != 0)) {
 740                         if ((oacl = acl_init(1)) == NULL)
 741                                 err(1, "acl_init() failed");
 742                         flag_new_acl = 1;
 743                         position = 0;
 744                 }
 745
 746                 if ((0 == flag_new_acl) && (optflags & (ACL_REMOVE_INHERIT_FLAG |
 747                                                         ACL_REMOVE_INHERITED_ENTRIES))) {
 748                         acl_t facl = NULL;
 749                         if ((facl = acl_init(1)) == NULL)
 750                                 err(1, "acl_init() failed");
 751                         for (aindex = 0;
 752                              acl_get_entry(oacl,
 753                                            (entry == NULL ? ACL_FIRST_ENTRY :
 754                                             ACL_NEXT_ENTRY), &entry) == 0;
 755                              aindex++) {
 756                                 acl_flagset_t eflags;
 757                                 acl_entry_t fent = NULL;
 758                                 if (acl_get_flagset_np(entry, &eflags) != 0) {
 759                                         err(1, "Unable to obtain flagset");
 760                                 }
 761
 762                                 if (acl_get_flag_np(eflags, ACL_ENTRY_INHERITED)) {
 763                                         if (optflags & ACL_REMOVE_INHERIT_FLAG) {
 764                                                 acl_delete_flag_np(eflags, ACL_ENTRY_INHERITED);
 765                                                 acl_set_flagset_np(entry, eflags);
 766                                                 acl_create_entry(&facl, &fent);
 767                                                 acl_copy_entry(fent, entry);
 768                                         }
 769                                 }
 770                                 else {
 771                                         acl_create_entry(&facl, &fent);
 772                                         acl_copy_entry(fent, entry);
 773                                 }
 774                         }
 775                         if (oacl)
 776                                 acl_free(oacl);
 777                         oacl = facl;
 778                 } else if (optflags & ACL_TO_STDOUT) {
 779                         ssize_t len; /* need to get printacl() from ls(1) */
 780                         char *text = acl_to_text(oacl, &len);
 781                         puts(text);
 782                         acl_free(text);
 783                 } else if (optflags & ACL_CHECK_CANONICITY) {
 784                         if (flag_new_acl) {
 785                                 warnx("No ACL currently associated with file '%s'", path);
 786                         }
 787                         retval = is_canonical(oacl);
 788                 } else if ((optflags & ACL_SET_FLAG) && (position == -1) &&
 789                     (!is_canonical(oacl))) {
 790                         warnx("The specified file '%s' does not have an ACL in canonical order, please specify a position with +a# ", path);
 791                         retval = 1;
 792                 } else if (((optflags & ACL_DELETE_FLAG) && (position != -1))
 793                     || (optflags & ACL_CHECK_CANONICITY)) {
 794                         retval = modify_acl(&oacl, NULL, optflags, position,
 795                                             inheritance_level, flag_new_acl, path);
 796                 } else if ((optflags & (ACL_REMOVE_INHERIT_FLAG|ACL_REMOVE_INHERITED_ENTRIES)) && flag_new_acl) {
 797                         warnx("No ACL currently associated with file '%s'", path);
 798                         retval = 1;
 799                 } else {
 800                         if (!modifier) { /* avoid bus error in acl_get_entry */
 801                                 errx(1, "Internal error: modifier should not be NULL");
 802                         }
 803                         for (aindex = 0;
 804                              acl_get_entry(modifier,
 805                                            (entry == NULL ? ACL_FIRST_ENTRY :
 806                                             ACL_NEXT_ENTRY), &entry) == 0;
 807                              aindex++) {
 808
 809                                 retval += modify_acl(&oacl, entry, optflags,
 810                                                      position, inheritance_level,
 811                                                      flag_new_acl, path);
 812                         }
 813                 }
 814         }
 815
 816 /* XXX Potential race here, since someone else could've modified or
 817  * read the ACL on this file (with the intention of modifying it) in
 818  * the interval from acl_get_file() to acl_set_file(); we can
 819  * minimize one aspect of this  window by comparing the original acl
 820  * to a fresh one from acl_get_file() but we could consider a
 821  * "changeset" mechanism, common locking  strategy, or kernel
 822  * supplied reservation mechanism to prevent this race.
 823  */
 824         if (!(optflags & (ACL_TO_STDOUT|ACL_CHECK_CANONICITY))) {
 825                 int status = -1;
 826                 if (follow) {
 827                         status = acl_set_file(path, ACL_TYPE_EXTENDED, oacl);
 828                 } else {
 829                         int fd = open(path, O_SYMLINK);
 830                         if (fd != -1) {
 831                                 status = acl_set_fd_np(fd, oacl,
 832                                                         ACL_TYPE_EXTENDED);
 833                                 close(fd);
 834                         }
 835                 }
 836                 if (status != 0) {
 837                         if (!fflag)
 838                                 warn("Failed to set ACL on file '%s'", path);
 839                         retval = 1;
 840                 }
 841         }
 842
 843         if (oacl)
 844                 acl_free(oacl);
 845
 846         return retval;
 847 }
 848
 849 #endif /*__APPLE__*/