gen.subproj/setmode.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1989, 1993, 1994
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * This code is derived from software contributed to Berkeley by
  27  * Dave Borman at Cray Research, Inc.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <sys/types.h>
  60 #include <sys/stat.h>
  61
  62 #include <ctype.h>
  63 #include <errno.h>
  64 #include <signal.h>
  65 #include <stddef.h>
  66 #include <stdlib.h>
  67
  68 #ifdef SETMODE_DEBUG
  69 #include <stdio.h>
  70 #endif
  71
  72 #define SET_LEN 6               /* initial # of bitcmd struct to malloc */
  73 #define SET_LEN_INCR 4          /* # of bitcmd structs to add as needed */
  74
  75 typedef struct bitcmd {
  76         char    cmd;
  77         char    cmd2;
  78         mode_t  bits;
  79 } BITCMD;
  80
  81 #define CMD2_CLR        0x01
  82 #define CMD2_SET        0x02
  83 #define CMD2_GBITS      0x04
  84 #define CMD2_OBITS      0x08
  85 #define CMD2_UBITS      0x10
  86
  87 static BITCMD   *addcmd __P((BITCMD *, int, int, int, u_int));
  88 static int       compress_mode __P((BITCMD *));
  89 #ifdef SETMODE_DEBUG
  90 static void      dumpmode __P((BITCMD *));
  91 #endif
  92
  93 /*
  94  * Given the old mode and an array of bitcmd structures, apply the operations
  95  * described in the bitcmd structures to the old mode, and return the new mode.
  96  * Note that there is no '=' command; a strict assignment is just a '-' (clear
  97  * bits) followed by a '+' (set bits).
  98  */
  99 mode_t
 100 getmode(bbox, omode)
 101         void *bbox;
 102         mode_t omode;
 103 {
 104         register BITCMD *set;
 105         register mode_t clrval, newmode, value;
 106
 107         set = (BITCMD *)bbox;
 108         newmode = omode;
 109         for (value = 0;; set++)
 110                 switch(set->cmd) {
 111                 /*
 112                  * When copying the user, group or other bits around, we "know"
 113                  * where the bits are in the mode so that we can do shifts to
 114                  * copy them around.  If we don't use shifts, it gets real
 115                  * grundgy with lots of single bit checks and bit sets.
 116                  */
 117                 case 'u':
 118                         value = (newmode & S_IRWXU) >> 6;
 119                         goto common;
 120
 121                 case 'g':
 122                         value = (newmode & S_IRWXG) >> 3;
 123                         goto common;
 124
 125                 case 'o':
 126                         value = newmode & S_IRWXO;
 127 common:                 if (set->cmd2 & CMD2_CLR) {
 128                                 clrval =
 129                                     (set->cmd2 & CMD2_SET) ?  S_IRWXO : value;
 130                                 if (set->cmd2 & CMD2_UBITS)
 131                                         newmode &= ~((clrval<<6) & set->bits);
 132                                 if (set->cmd2 & CMD2_GBITS)
 133                                         newmode &= ~((clrval<<3) & set->bits);
 134                                 if (set->cmd2 & CMD2_OBITS)
 135                                         newmode &= ~(clrval & set->bits);
 136                         }
 137                         if (set->cmd2 & CMD2_SET) {
 138                                 if (set->cmd2 & CMD2_UBITS)
 139                                         newmode |= (value<<6) & set->bits;
 140                                 if (set->cmd2 & CMD2_GBITS)
 141                                         newmode |= (value<<3) & set->bits;
 142                                 if (set->cmd2 & CMD2_OBITS)
 143                                         newmode |= value & set->bits;
 144                         }
 145                         break;
 146
 147                 case '+':
 148                         newmode |= set->bits;
 149                         break;
 150
 151                 case '-':
 152                         newmode &= ~set->bits;
 153                         break;
 154
 155                 case 'X':
 156                         if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
 157                                 newmode |= set->bits;
 158                         break;
 159
 160                 case '\0':
 161                 default:
 162 #ifdef SETMODE_DEBUG
 163                         (void)printf("getmode:%04o -> %04o\n", omode, newmode);
 164 #endif
 165                         return (newmode);
 166                 }
 167 }
 168
 169 #define ADDCMD(a, b, c, d)                                              \
 170         if (set >= endset) {                                            \
 171                 register BITCMD *newset;                                \
 172                 setlen += SET_LEN_INCR;                                 \
 173                 newset = realloc(saveset, sizeof(BITCMD) * setlen);     \
 174                 if (!saveset)                                           \
 175                         return (NULL);                                  \
 176                 set = newset + (set - saveset);                         \
 177                 saveset = newset;                                       \
 178                 endset = newset + (setlen - 2);                         \
 179         }                                                               \
 180         set = addcmd(set, (a), (b), (c), (d))
 181
 182 #define STANDARD_BITS   (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
 183
 184 void *
 185 setmode(p)
 186         register char *p;
 187 {
 188         register int perm, who;
 189         register char op;
 190         BITCMD *set, *saveset, *endset;
 191         sigset_t sigset, sigoset;
 192         mode_t mask;
 193         int equalopdone, permXbits, setlen;
 194
 195         if (!*p)
 196                 return (NULL);
 197
 198         /*
 199          * Get a copy of the mask for the permissions that are mask relative.
 200          * Flip the bits, we want what's not set.  Since it's possible that
 201          * the caller is opening files inside a signal handler, protect them
 202          * as best we can.
 203          */
 204         sigfillset(&sigset);
 205         (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset);
 206         (void)umask(mask = umask(0));
 207         mask = ~mask;
 208         (void)sigprocmask(SIG_SETMASK, &sigoset, NULL);
 209
 210         setlen = SET_LEN + 2;
 211
 212         if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL)
 213                 return (NULL);
 214         saveset = set;
 215         endset = set + (setlen - 2);
 216
 217         /*
 218          * If an absolute number, get it and return; disallow non-octal digits
 219          * or illegal bits.
 220          */
 221         if (isdigit(*p)) {
 222                 perm = (mode_t)strtol(p, NULL, 8);
 223                 if (perm & ~(STANDARD_BITS|S_ISTXT)) {
 224                         free(saveset);
 225                         return (NULL);
 226                 }
 227                 while (*++p)
 228                         if (*p < '0' || *p > '7') {
 229                                 free(saveset);
 230                                 return (NULL);
 231                         }
 232                 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
 233                 return (saveset);
 234         }
 235
 236         /*
 237          * Build list of structures to set/clear/copy bits as described by
 238          * each clause of the symbolic mode.
 239          */
 240         for (;;) {
 241                 /* First, find out which bits might be modified. */
 242                 for (who = 0;; ++p) {
 243                         switch (*p) {
 244                         case 'a':
 245                                 who |= STANDARD_BITS;
 246                                 break;
 247                         case 'u':
 248                                 who |= S_ISUID|S_IRWXU;
 249                                 break;
 250                         case 'g':
 251                                 who |= S_ISGID|S_IRWXG;
 252                                 break;
 253                         case 'o':
 254                                 who |= S_IRWXO;
 255                                 break;
 256                         default:
 257                                 goto getop;
 258                         }
 259                 }
 260
 261 getop:          if ((op = *p++) != '+' && op != '-' && op != '=') {
 262                         free(saveset);
 263                         return (NULL);
 264                 }
 265                 if (op == '=')
 266                         equalopdone = 0;
 267
 268                 who &= ~S_ISTXT;
 269                 for (perm = 0, permXbits = 0;; ++p) {
 270                         switch (*p) {
 271                         case 'r':
 272                                 perm |= S_IRUSR|S_IRGRP|S_IROTH;
 273                                 break;
 274                         case 's':
 275                                 /* If only "other" bits ignore set-id. */
 276                                 if (who & ~S_IRWXO)
 277                                         perm |= S_ISUID|S_ISGID;
 278                                 break;
 279                         case 't':
 280                                 /* If only "other" bits ignore sticky. */
 281                                 if (who & ~S_IRWXO) {
 282                                         who |= S_ISTXT;
 283                                         perm |= S_ISTXT;
 284                                 }
 285                                 break;
 286                         case 'w':
 287                                 perm |= S_IWUSR|S_IWGRP|S_IWOTH;
 288                                 break;
 289                         case 'X':
 290                                 permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
 291                                 break;
 292                         case 'x':
 293                                 perm |= S_IXUSR|S_IXGRP|S_IXOTH;
 294                                 break;
 295                         case 'u':
 296                         case 'g':
 297                         case 'o':
 298                                 /*
 299                                  * When ever we hit 'u', 'g', or 'o', we have
 300                                  * to flush out any partial mode that we have,
 301                                  * and then do the copying of the mode bits.
 302                                  */
 303                                 if (perm) {
 304                                         ADDCMD(op, who, perm, mask);
 305                                         perm = 0;
 306                                 }
 307                                 if (op == '=')
 308                                         equalopdone = 1;
 309                                 if (op == '+' && permXbits) {
 310                                         ADDCMD('X', who, permXbits, mask);
 311                                         permXbits = 0;
 312                                 }
 313                                 ADDCMD(*p, who, op, mask);
 314                                 break;
 315
 316                         default:
 317                                 /*
 318                                  * Add any permissions that we haven't already
 319                                  * done.
 320                                  */
 321                                 if (perm || (op == '=' && !equalopdone)) {
 322                                         if (op == '=')
 323                                                 equalopdone = 1;
 324                                         ADDCMD(op, who, perm, mask);
 325                                         perm = 0;
 326                                 }
 327                                 if (permXbits) {
 328                                         ADDCMD('X', who, permXbits, mask);
 329                                         permXbits = 0;
 330                                 }
 331                                 goto apply;
 332                         }
 333                 }
 334
 335 apply:          if (!*p)
 336                         break;
 337                 if (*p != ',')
 338                         goto getop;
 339                 ++p;
 340         }
 341         set->cmd = 0;
 342 #ifdef SETMODE_DEBUG
 343         (void)printf("Before compress_mode()\n");
 344         dumpmode(saveset);
 345 #endif
 346         compress_mode(saveset);
 347 #ifdef SETMODE_DEBUG
 348         (void)printf("After compress_mode()\n");
 349         dumpmode(saveset);
 350 #endif
 351         return (saveset);
 352 }
 353
 354 static BITCMD *
 355 addcmd(set, op, who, oparg, mask)
 356         BITCMD *set;
 357         register int oparg, who;
 358         register int op;
 359         u_int mask;
 360 {
 361         switch (op) {
 362         case '=':
 363                 set->cmd = '-';
 364                 set->bits = who ? who : STANDARD_BITS;
 365                 set++;
 366
 367                 op = '+';
 368                 /* FALLTHROUGH */
 369         case '+':
 370         case '-':
 371         case 'X':
 372                 set->cmd = op;
 373                 set->bits = (who ? who : mask) & oparg;
 374                 break;
 375
 376         case 'u':
 377         case 'g':
 378         case 'o':
 379                 set->cmd = op;
 380                 if (who) {
 381                         set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
 382                                     ((who & S_IRGRP) ? CMD2_GBITS : 0) |
 383                                     ((who & S_IROTH) ? CMD2_OBITS : 0);
 384                         set->bits = ~0;
 385                 } else {
 386                         set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
 387                         set->bits = mask;
 388                 }
 389
 390                 if (oparg == '+')
 391                         set->cmd2 |= CMD2_SET;
 392                 else if (oparg == '-')
 393                         set->cmd2 |= CMD2_CLR;
 394                 else if (oparg == '=')
 395                         set->cmd2 |= CMD2_SET|CMD2_CLR;
 396                 break;
 397         }
 398         return (set + 1);
 399 }
 400
 401 #ifdef SETMODE_DEBUG
 402 static void
 403 dumpmode(set)
 404         register BITCMD *set;
 405 {
 406         for (; set->cmd; ++set)
 407                 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
 408                     set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
 409                     set->cmd2 & CMD2_CLR ? " CLR" : "",
 410                     set->cmd2 & CMD2_SET ? " SET" : "",
 411                     set->cmd2 & CMD2_UBITS ? " UBITS" : "",
 412                     set->cmd2 & CMD2_GBITS ? " GBITS" : "",
 413                     set->cmd2 & CMD2_OBITS ? " OBITS" : "");
 414 }
 415 #endif
 416
 417 /*
 418  * Given an array of bitcmd structures, compress by compacting consecutive
 419  * '+', '-' and 'X' commands into at most 3 commands, one of each.  The 'u',
 420  * 'g' and 'o' commands continue to be separate.  They could probably be
 421  * compacted, but it's not worth the effort.
 422  */
 423 static int
 424 compress_mode(set)
 425         register BITCMD *set;
 426 {
 427         register BITCMD *nset;
 428         register int setbits, clrbits, Xbits, op;
 429
 430         for (nset = set;;) {
 431                 /* Copy over any 'u', 'g' and 'o' commands. */
 432                 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
 433                         *set++ = *nset++;
 434                         if (!op)
 435                                 return;
 436                 }
 437
 438                 for (setbits = clrbits = Xbits = 0;; nset++) {
 439                         if ((op = nset->cmd) == '-') {
 440                                 clrbits |= nset->bits;
 441                                 setbits &= ~nset->bits;
 442                                 Xbits &= ~nset->bits;
 443                         } else if (op == '+') {
 444                                 setbits |= nset->bits;
 445                                 clrbits &= ~nset->bits;
 446                                 Xbits &= ~nset->bits;
 447                         } else if (op == 'X')
 448                                 Xbits |= nset->bits & ~setbits;
 449                         else
 450                                 break;
 451                 }
 452                 if (clrbits) {
 453                         set->cmd = '-';
 454                         set->cmd2 = 0;
 455                         set->bits = clrbits;
 456                         set++;
 457                 }
 458                 if (setbits) {
 459                         set->cmd = '+';
 460                         set->cmd2 = 0;
 461                         set->bits = setbits;
 462                         set++;
 463                 }
 464                 if (Xbits) {
 465                         set->cmd = 'X';
 466                         set->cmd2 = 0;
 467                         set->bits = Xbits;
 468                         set++;
 469                 }
 470         }
 471 }