gen/setmode-fbsd.c

   1 /*
   2  * Copyright (c) 1989, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Dave Borman at Cray Research, Inc.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)setmode.c   8.2 (Berkeley) 3/25/94";
  39 #endif /* LIBC_SCCS and not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: src/lib/libc/gen/setmode.c,v 1.9 2003/02/23 00:24:03 mikeh Exp $");
  42
  43 #include "namespace.h"
  44 #include <sys/types.h>
  45 #include <sys/stat.h>
  46
  47 #include <ctype.h>
  48 #include <signal.h>
  49 #include <stddef.h>
  50 #include <stdlib.h>
  51 #include <unistd.h>
  52
  53 #ifdef SETMODE_DEBUG
  54 #include <stdio.h>
  55 #endif
  56 #include "un-namespace.h"
  57
  58 #define SET_LEN 6               /* initial # of bitcmd struct to malloc */
  59 #define SET_LEN_INCR 4          /* # of bitcmd structs to add as needed */
  60
  61 typedef struct bitcmd {
  62         char    cmd;
  63         char    cmd2;
  64         mode_t  bits;
  65 } BITCMD;
  66
  67 #define CMD2_CLR        0x01
  68 #define CMD2_SET        0x02
  69 #define CMD2_GBITS      0x04
  70 #define CMD2_OBITS      0x08
  71 #define CMD2_UBITS      0x10
  72
  73 #define compress_mode   _sm_compress_mode
  74
  75 static BITCMD   *addcmd(BITCMD *, int, int, int, u_int);
  76 __private_extern__ void         compress_mode(BITCMD *);
  77 #ifdef SETMODE_DEBUG
  78 static void      dumpmode(BITCMD *);
  79 #endif
  80
  81 #ifndef BUILDING_VARIANT
  82 /*
  83  * Given the old mode and an array of bitcmd structures, apply the operations
  84  * described in the bitcmd structures to the old mode, and return the new mode.
  85  * Note that there is no '=' command; a strict assignment is just a '-' (clear
  86  * bits) followed by a '+' (set bits).
  87  */
  88 mode_t
  89 getmode(bbox, omode)
  90         const void *bbox;
  91         mode_t omode;
  92 {
  93         const BITCMD *set;
  94         mode_t clrval, newmode, value;
  95
  96         set = (const BITCMD *)bbox;
  97         newmode = omode;
  98         for (value = 0;; set++)
  99                 switch(set->cmd) {
 100                 /*
 101                  * When copying the user, group or other bits around, we "know"
 102                  * where the bits are in the mode so that we can do shifts to
 103                  * copy them around.  If we don't use shifts, it gets real
 104                  * grundgy with lots of single bit checks and bit sets.
 105                  */
 106                 case 'u':
 107                         value = (newmode & S_IRWXU) >> 6;
 108                         goto common;
 109
 110                 case 'g':
 111                         value = (newmode & S_IRWXG) >> 3;
 112                         goto common;
 113
 114                 case 'o':
 115                         value = newmode & S_IRWXO;
 116 common:                 if (set->cmd2 & CMD2_CLR) {
 117                                 clrval =
 118                                     (set->cmd2 & CMD2_SET) ?  S_IRWXO : value;
 119                                 if (set->cmd2 & CMD2_UBITS)
 120                                         newmode &= ~((clrval<<6) & set->bits);
 121                                 if (set->cmd2 & CMD2_GBITS)
 122                                         newmode &= ~((clrval<<3) & set->bits);
 123                                 if (set->cmd2 & CMD2_OBITS)
 124                                         newmode &= ~(clrval & set->bits);
 125                         }
 126                         if (set->cmd2 & CMD2_SET) {
 127                                 if (set->cmd2 & CMD2_UBITS)
 128                                         newmode |= (value<<6) & set->bits;
 129                                 if (set->cmd2 & CMD2_GBITS)
 130                                         newmode |= (value<<3) & set->bits;
 131                                 if (set->cmd2 & CMD2_OBITS)
 132                                         newmode |= value & set->bits;
 133                         }
 134                         break;
 135
 136                 case '+':
 137                         newmode |= set->bits;
 138                         break;
 139
 140                 case '-':
 141                         newmode &= ~set->bits;
 142                         break;
 143
 144                 case 'X':
 145                         if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
 146                                 newmode |= set->bits;
 147                         break;
 148
 149                 case '\0':
 150                 default:
 151 #ifdef SETMODE_DEBUG
 152                         (void)printf("getmode:%04o -> %04o\n", omode, newmode);
 153 #endif
 154                         return (newmode);
 155                 }
 156 }
 157 #endif /* BUILDING_VARIANT */
 158
 159 #define ADDCMD(a, b, c, d)                                              \
 160         if (set >= endset) {                                            \
 161                 BITCMD *newset;                                         \
 162                 setlen += SET_LEN_INCR;                                 \
 163                 newset = realloc(saveset, sizeof(BITCMD) * setlen);     \
 164                 if (!newset) {                                          \
 165                         if (saveset)                                    \
 166                                 free(saveset);                          \
 167                         saveset = NULL;                                 \
 168                         return (NULL);                                  \
 169                 }                                                       \
 170                 set = newset + (set - saveset);                         \
 171                 saveset = newset;                                       \
 172                 endset = newset + (setlen - 2);                         \
 173         }                                                               \
 174         set = addcmd(set, (a), (b), (c), (d))
 175
 176 #ifndef VARIANT_LEGACY
 177 #define STANDARD_BITS   (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO|S_ISTXT)
 178 #else /* VARIANT_LEGACY */
 179 #define STANDARD_BITS   (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
 180 #endif /* !VARIANT_LEGACY */
 181
 182 void *
 183 setmode(p)
 184         const char *p;
 185 {
 186         int perm, who;
 187         char op, *ep;
 188         BITCMD *set, *saveset, *endset;
 189         sigset_t sigset, sigoset;
 190         mode_t mask;
 191         int equalopdone=0, permXbits, setlen;
 192         long perml;
 193
 194         if (!*p)
 195                 return (NULL);
 196
 197         /*
 198          * Get a copy of the mask for the permissions that are mask relative.
 199          * Flip the bits, we want what's not set.  Since it's possible that
 200          * the caller is opening files inside a signal handler, protect them
 201          * as best we can.
 202          */
 203         sigfillset(&sigset);
 204         (void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset);
 205         (void)umask(mask = umask(0));
 206         mask = ~mask;
 207         (void)_sigprocmask(SIG_SETMASK, &sigoset, NULL);
 208
 209         setlen = SET_LEN + 2;
 210
 211         if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL)
 212                 return (NULL);
 213         saveset = set;
 214         endset = set + (setlen - 2);
 215
 216         /*
 217          * If an absolute number, get it and return; disallow non-octal digits
 218          * or illegal bits.
 219          */
 220         if (isdigit((unsigned char)*p)) {
 221                 perml = strtol(p, &ep, 8);
 222 #ifndef VARIANT_LEGACY
 223                 if (*ep || perml < 0 || perml & ~STANDARD_BITS)
 224 #else /* VARIANT_LEGACY */
 225                 if (*ep || perml < 0 || perml & ~(STANDARD_BITS|S_ISTXT))
 226 #endif /* !VARIANT_LEGACY */
 227                 {
 228                         free(saveset);
 229                         return (NULL);
 230                 }
 231                 perm = (mode_t)perml;
 232 #ifndef VARIANT_LEGACY
 233                 ADDCMD('=', STANDARD_BITS, perm, mask);
 234 #else /* VARIANT_LEGACY */
 235                 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
 236 #endif /* !VARIANT_LEGACY */
 237                 set->cmd = 0;
 238                 return (saveset);
 239         }
 240
 241         /*
 242          * Build list of structures to set/clear/copy bits as described by
 243          * each clause of the symbolic mode.
 244          */
 245         for (;;) {
 246                 /* First, find out which bits might be modified. */
 247                 for (who = 0;; ++p) {
 248                         switch (*p) {
 249                         case 'a':
 250                                 who |= STANDARD_BITS;
 251                                 break;
 252                         case 'u':
 253                                 who |= S_ISUID|S_IRWXU;
 254                                 break;
 255                         case 'g':
 256                                 who |= S_ISGID|S_IRWXG;
 257                                 break;
 258                         case 'o':
 259                                 who |= S_IRWXO;
 260                                 break;
 261                         default:
 262                                 goto getop;
 263                         }
 264                 }
 265
 266 getop:          if ((op = *p++) != '+' && op != '-' && op != '=') {
 267                         free(saveset);
 268                         return (NULL);
 269                 }
 270                 if (op == '=')
 271                         equalopdone = 0;
 272
 273 #ifdef VARIANT_LEGACY
 274                 who &= ~S_ISTXT;
 275 #endif /* VARIANT_LEGACY */
 276                 for (perm = 0, permXbits = 0;; ++p) {
 277                         switch (*p) {
 278                         case 'r':
 279                                 perm |= S_IRUSR|S_IRGRP|S_IROTH;
 280                                 break;
 281                         case 's':
 282                                 /* If only "other" bits ignore set-id. */
 283                                 if (!who || who & ~S_IRWXO)
 284                                         perm |= S_ISUID|S_ISGID;
 285                                 break;
 286                         case 't':
 287                                 /* If only "other" bits ignore sticky. */
 288                                 if (!who || who & ~S_IRWXO) {
 289 #ifdef VARIANT_LEGACY
 290                                         who |= S_ISTXT;
 291 #endif /* VARIANT_LEGACY */
 292                                         perm |= S_ISTXT;
 293                                 }
 294                                 break;
 295                         case 'w':
 296                                 perm |= S_IWUSR|S_IWGRP|S_IWOTH;
 297                                 break;
 298                         case 'X':
 299                                 permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
 300                                 break;
 301                         case 'x':
 302                                 perm |= S_IXUSR|S_IXGRP|S_IXOTH;
 303                                 break;
 304                         case 'u':
 305                         case 'g':
 306                         case 'o':
 307                                 /*
 308                                  * When ever we hit 'u', 'g', or 'o', we have
 309                                  * to flush out any partial mode that we have,
 310                                  * and then do the copying of the mode bits.
 311                                  */
 312                                 if (perm) {
 313                                         ADDCMD(op, who, perm, mask);
 314                                         perm = 0;
 315                                 }
 316                                 if (op == '=')
 317                                         equalopdone = 1;
 318                                 if (op == '+' && permXbits) {
 319                                         ADDCMD('X', who, permXbits, mask);
 320                                         permXbits = 0;
 321                                 }
 322                                 ADDCMD(*p, who, op, mask);
 323                                 break;
 324
 325                         default:
 326                                 /*
 327                                  * Add any permissions that we haven't already
 328                                  * done.
 329                                  */
 330                                 if (perm || (op == '=' && !equalopdone)) {
 331                                         if (op == '=')
 332                                                 equalopdone = 1;
 333                                         ADDCMD(op, who, perm, mask);
 334                                         perm = 0;
 335                                 }
 336                                 if (permXbits) {
 337                                         ADDCMD('X', who, permXbits, mask);
 338                                         permXbits = 0;
 339                                 }
 340                                 goto apply;
 341                         }
 342                 }
 343
 344 apply:          if (!*p)
 345                         break;
 346                 if (*p != ',')
 347                         goto getop;
 348                 ++p;
 349         }
 350         set->cmd = 0;
 351 #ifdef SETMODE_DEBUG
 352         (void)printf("Before compress_mode()\n");
 353         dumpmode(saveset);
 354 #endif
 355         compress_mode(saveset);
 356 #ifdef SETMODE_DEBUG
 357         (void)printf("After compress_mode()\n");
 358         dumpmode(saveset);
 359 #endif
 360         return (saveset);
 361 }
 362
 363 static BITCMD *
 364 addcmd(set, op, who, oparg, mask)
 365         BITCMD *set;
 366         int oparg, who;
 367         int op;
 368         u_int mask;
 369 {
 370         switch (op) {
 371         case '=':
 372                 set->cmd = '-';
 373                 set->bits = who ? who : STANDARD_BITS;
 374                 set++;
 375
 376                 op = '+';
 377                 /* FALLTHROUGH */
 378         case '+':
 379         case '-':
 380         case 'X':
 381                 set->cmd = op;
 382                 set->bits = (who ? who : mask) & oparg;
 383                 break;
 384
 385         case 'u':
 386         case 'g':
 387         case 'o':
 388                 set->cmd = op;
 389                 if (who) {
 390                         set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
 391                                     ((who & S_IRGRP) ? CMD2_GBITS : 0) |
 392                                     ((who & S_IROTH) ? CMD2_OBITS : 0);
 393                         set->bits = (mode_t)~0;
 394                 } else {
 395                         set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
 396                         set->bits = mask;
 397                 }
 398
 399                 if (oparg == '+')
 400                         set->cmd2 |= CMD2_SET;
 401                 else if (oparg == '-')
 402                         set->cmd2 |= CMD2_CLR;
 403                 else if (oparg == '=')
 404                         set->cmd2 |= CMD2_SET|CMD2_CLR;
 405                 break;
 406         }
 407         return (set + 1);
 408 }
 409
 410 #ifdef SETMODE_DEBUG
 411 static void
 412 dumpmode(set)
 413         BITCMD *set;
 414 {
 415         for (; set->cmd; ++set)
 416                 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
 417                     set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
 418                     set->cmd2 & CMD2_CLR ? " CLR" : "",
 419                     set->cmd2 & CMD2_SET ? " SET" : "",
 420                     set->cmd2 & CMD2_UBITS ? " UBITS" : "",
 421                     set->cmd2 & CMD2_GBITS ? " GBITS" : "",
 422                     set->cmd2 & CMD2_OBITS ? " OBITS" : "");
 423 }
 424 #endif
 425
 426 #ifndef BUILDING_VARIANT
 427 /*
 428  * Given an array of bitcmd structures, compress by compacting consecutive
 429  * '+', '-' and 'X' commands into at most 3 commands, one of each.  The 'u',
 430  * 'g' and 'o' commands continue to be separate.  They could probably be
 431  * compacted, but it's not worth the effort.
 432  */
 433 __private_extern__ void
 434 compress_mode(set)
 435         BITCMD *set;
 436 {
 437         BITCMD *nset;
 438         int setbits, clrbits, Xbits, op;
 439
 440         for (nset = set;;) {
 441                 /* Copy over any 'u', 'g' and 'o' commands. */
 442                 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
 443                         *set++ = *nset++;
 444                         if (!op)
 445                                 return;
 446                 }
 447
 448                 for (setbits = clrbits = Xbits = 0;; nset++) {
 449                         if ((op = nset->cmd) == '-') {
 450                                 clrbits |= nset->bits;
 451                                 setbits &= ~nset->bits;
 452                                 Xbits &= ~nset->bits;
 453                         } else if (op == '+') {
 454                                 setbits |= nset->bits;
 455                                 clrbits &= ~nset->bits;
 456                                 Xbits &= ~nset->bits;
 457                         } else if (op == 'X')
 458                                 Xbits |= nset->bits & ~setbits;
 459                         else
 460                                 break;
 461                 }
 462                 if (clrbits) {
 463                         set->cmd = '-';
 464                         set->cmd2 = 0;
 465                         set->bits = clrbits;
 466                         set++;
 467                 }
 468                 if (setbits) {
 469                         set->cmd = '+';
 470                         set->cmd2 = 0;
 471                         set->bits = setbits;
 472                         set++;
 473                 }
 474                 if (Xbits) {
 475                         set->cmd = 'X';
 476                         set->cmd2 = 0;
 477                         set->bits = Xbits;
 478                         set++;
 479                 }
 480         }
 481 }
 482 #endif /* BUILDING_VARIANT */