gen/FreeBSD/setmode.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  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)setmode.c   8.2 (Berkeley) 3/25/94";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD: src/lib/libc/gen/setmode.c,v 1.11 2007/01/09 00:27:55 imp Exp $");
  38
  39 #include "namespace.h"
  40 #include <sys/types.h>
  41 #include <sys/stat.h>
  42
  43 #include <ctype.h>
  44 #include <signal.h>
  45 #include <stddef.h>
  46 #include <stdlib.h>
  47 #include <unistd.h>
  48
  49 #ifdef SETMODE_DEBUG
  50 #include <stdio.h>
  51 #endif
  52 #include "un-namespace.h"
  53
  54 #define SET_LEN 6               /* initial # of bitcmd struct to malloc */
  55 #define SET_LEN_INCR 4          /* # of bitcmd structs to add as needed */
  56
  57 typedef struct bitcmd {
  58         char    cmd;
  59         char    cmd2;
  60         mode_t  bits;
  61 } BITCMD;
  62
  63 #define CMD2_CLR        0x01
  64 #define CMD2_SET        0x02
  65 #define CMD2_GBITS      0x04
  66 #define CMD2_OBITS      0x08
  67 #define CMD2_UBITS      0x10
  68
  69 #define compress_mode   _sm_compress_mode
  70
  71 static BITCMD   *addcmd(BITCMD *, int, int, int, u_int);
  72 __private_extern__ void         compress_mode(BITCMD *);
  73 #ifdef SETMODE_DEBUG
  74 static void      dumpmode(BITCMD *);
  75 #endif
  76
  77 #ifndef BUILDING_VARIANT
  78 /*
  79  * Given the old mode and an array of bitcmd structures, apply the operations
  80  * described in the bitcmd structures to the old mode, and return the new mode.
  81  * Note that there is no '=' command; a strict assignment is just a '-' (clear
  82  * bits) followed by a '+' (set bits).
  83  */
  84 mode_t
  85 getmode(const void *bbox, mode_t omode)
  86 {
  87         const BITCMD *set;
  88         mode_t clrval, newmode, value;
  89
  90         set = (const BITCMD *)bbox;
  91         newmode = omode;
  92         for (value = 0;; set++)
  93                 switch(set->cmd) {
  94                 /*
  95                  * When copying the user, group or other bits around, we "know"
  96                  * where the bits are in the mode so that we can do shifts to
  97                  * copy them around.  If we don't use shifts, it gets real
  98                  * grundgy with lots of single bit checks and bit sets.
  99                  */
 100                 case 'u':
 101                         value = (newmode & S_IRWXU) >> 6;
 102                         goto common;
 103
 104                 case 'g':
 105                         value = (newmode & S_IRWXG) >> 3;
 106                         goto common;
 107
 108                 case 'o':
 109                         value = newmode & S_IRWXO;
 110 common:                 if (set->cmd2 & CMD2_CLR) {
 111                                 clrval =
 112                                     (set->cmd2 & CMD2_SET) ?  S_IRWXO : value;
 113                                 if (set->cmd2 & CMD2_UBITS)
 114                                         newmode &= ~((clrval<<6) & set->bits);
 115                                 if (set->cmd2 & CMD2_GBITS)
 116                                         newmode &= ~((clrval<<3) & set->bits);
 117                                 if (set->cmd2 & CMD2_OBITS)
 118                                         newmode &= ~(clrval & set->bits);
 119                         }
 120                         if (set->cmd2 & CMD2_SET) {
 121                                 if (set->cmd2 & CMD2_UBITS)
 122                                         newmode |= (value<<6) & set->bits;
 123                                 if (set->cmd2 & CMD2_GBITS)
 124                                         newmode |= (value<<3) & set->bits;
 125                                 if (set->cmd2 & CMD2_OBITS)
 126                                         newmode |= value & set->bits;
 127                         }
 128                         break;
 129
 130                 case '+':
 131                         newmode |= set->bits;
 132                         break;
 133
 134                 case '-':
 135                         newmode &= ~set->bits;
 136                         break;
 137
 138                 case 'X':
 139                         if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
 140                                 newmode |= set->bits;
 141                         break;
 142
 143                 case '\0':
 144                 default:
 145 #ifdef SETMODE_DEBUG
 146                         (void)printf("getmode:%04o -> %04o\n", omode, newmode);
 147 #endif
 148                         return (newmode);
 149                 }
 150 }
 151 #endif /* BUILDING_VARIANT */
 152
 153 #define ADDCMD(a, b, c, d)                                              \
 154         if (set >= endset) {                                            \
 155                 BITCMD *newset;                                         \
 156                 setlen += SET_LEN_INCR;                                 \
 157                 newset = realloc(saveset, sizeof(BITCMD) * setlen);     \
 158                 if (!newset) {                                          \
 159                         if (saveset)                                    \
 160                                 free(saveset);                          \
 161                         saveset = NULL;                                 \
 162                         return (NULL);                                  \
 163                 }                                                       \
 164                 set = newset + (set - saveset);                         \
 165                 saveset = newset;                                       \
 166                 endset = newset + (setlen - 2);                         \
 167         }                                                               \
 168         set = addcmd(set, (a), (b), (c), (d))
 169
 170 #ifndef VARIANT_LEGACY
 171 #define STANDARD_BITS   (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO|S_ISTXT)
 172 #else /* VARIANT_LEGACY */
 173 #define STANDARD_BITS   (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
 174 #endif /* !VARIANT_LEGACY */
 175
 176 void *
 177 setmode(const char *p)
 178 {
 179         int perm, who;
 180         char op, *ep;
 181         BITCMD *set, *saveset, *endset;
 182         sigset_t sigset, sigoset;
 183         mode_t mask;
 184         int equalopdone=0, permXbits, setlen;
 185         long perml;
 186
 187         if (!*p)
 188                 return (NULL);
 189
 190         /*
 191          * Get a copy of the mask for the permissions that are mask relative.
 192          * Flip the bits, we want what's not set.  Since it's possible that
 193          * the caller is opening files inside a signal handler, protect them
 194          * as best we can.
 195          */
 196         sigfillset(&sigset);
 197         (void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset);
 198         (void)umask(mask = umask(0));
 199         mask = ~mask;
 200         (void)_sigprocmask(SIG_SETMASK, &sigoset, NULL);
 201
 202         setlen = SET_LEN + 2;
 203
 204         if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL)
 205                 return (NULL);
 206         saveset = set;
 207         endset = set + (setlen - 2);
 208
 209         /*
 210          * If an absolute number, get it and return; disallow non-octal digits
 211          * or illegal bits.
 212          */
 213         if (isdigit((unsigned char)*p)) {
 214                 perml = strtol(p, &ep, 8);
 215 #ifndef VARIANT_LEGACY
 216                 if (*ep || perml < 0 || perml & ~STANDARD_BITS)
 217 #else /* VARIANT_LEGACY */
 218                 if (*ep || perml < 0 || perml & ~(STANDARD_BITS|S_ISTXT))
 219 #endif /* !VARIANT_LEGACY */
 220                 {
 221                         free(saveset);
 222                         return (NULL);
 223                 }
 224                 perm = (mode_t)perml;
 225 #ifndef VARIANT_LEGACY
 226                 ADDCMD('=', STANDARD_BITS, perm, mask);
 227 #else /* VARIANT_LEGACY */
 228                 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
 229 #endif /* !VARIANT_LEGACY */
 230                 set->cmd = 0;
 231                 return (saveset);
 232         }
 233
 234         /*
 235          * Build list of structures to set/clear/copy bits as described by
 236          * each clause of the symbolic mode.
 237          */
 238         for (;;) {
 239                 /* First, find out which bits might be modified. */
 240                 for (who = 0;; ++p) {
 241                         switch (*p) {
 242                         case 'a':
 243                                 who |= STANDARD_BITS;
 244                                 break;
 245                         case 'u':
 246                                 who |= S_ISUID|S_IRWXU;
 247                                 break;
 248                         case 'g':
 249                                 who |= S_ISGID|S_IRWXG;
 250                                 break;
 251                         case 'o':
 252                                 who |= S_IRWXO;
 253                                 break;
 254                         default:
 255                                 goto getop;
 256                         }
 257                 }
 258
 259 getop:          if ((op = *p++) != '+' && op != '-' && op != '=') {
 260                         free(saveset);
 261                         return (NULL);
 262                 }
 263                 if (op == '=')
 264                         equalopdone = 0;
 265
 266 #ifdef VARIANT_LEGACY
 267                 who &= ~S_ISTXT;
 268 #endif /* VARIANT_LEGACY */
 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 || who & ~S_IRWXO)
 277                                         perm |= S_ISUID|S_ISGID;
 278                                 break;
 279                         case 't':
 280                                 /* If only "other" bits ignore sticky. */
 281                                 if (!who || who & ~S_IRWXO) {
 282 #ifdef VARIANT_LEGACY
 283                                         who |= S_ISTXT;
 284 #endif /* VARIANT_LEGACY */
 285                                         perm |= S_ISTXT;
 286                                 }
 287                                 break;
 288                         case 'w':
 289                                 perm |= S_IWUSR|S_IWGRP|S_IWOTH;
 290                                 break;
 291                         case 'X':
 292                                 permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
 293                                 break;
 294                         case 'x':
 295                                 perm |= S_IXUSR|S_IXGRP|S_IXOTH;
 296                                 break;
 297                         case 'u':
 298                         case 'g':
 299                         case 'o':
 300                                 /*
 301                                  * When ever we hit 'u', 'g', or 'o', we have
 302                                  * to flush out any partial mode that we have,
 303                                  * and then do the copying of the mode bits.
 304                                  */
 305                                 if (perm) {
 306                                         ADDCMD(op, who, perm, mask);
 307                                         perm = 0;
 308                                 }
 309                                 if (op == '=')
 310                                         equalopdone = 1;
 311                                 if (op == '+' && permXbits) {
 312                                         ADDCMD('X', who, permXbits, mask);
 313                                         permXbits = 0;
 314                                 }
 315                                 ADDCMD(*p, who, op, mask);
 316                                 break;
 317
 318                         default:
 319                                 /*
 320                                  * Add any permissions that we haven't already
 321                                  * done.
 322                                  */
 323                                 if (perm || (op == '=' && !equalopdone)) {
 324                                         if (op == '=')
 325                                                 equalopdone = 1;
 326                                         ADDCMD(op, who, perm, mask);
 327                                         perm = 0;
 328                                 }
 329                                 if (permXbits) {
 330                                         ADDCMD('X', who, permXbits, mask);
 331                                         permXbits = 0;
 332                                 }
 333                                 goto apply;
 334                         }
 335                 }
 336
 337 apply:          if (!*p)
 338                         break;
 339                 if (*p != ',')
 340                         goto getop;
 341                 ++p;
 342         }
 343         set->cmd = 0;
 344 #ifdef SETMODE_DEBUG
 345         (void)printf("Before compress_mode()\n");
 346         dumpmode(saveset);
 347 #endif
 348         compress_mode(saveset);
 349 #ifdef SETMODE_DEBUG
 350         (void)printf("After compress_mode()\n");
 351         dumpmode(saveset);
 352 #endif
 353         return (saveset);
 354 }
 355
 356 static BITCMD *
 357 addcmd(BITCMD *set, int op, int who, int oparg, u_int mask)
 358 {
 359         switch (op) {
 360         case '=':
 361                 set->cmd = '-';
 362                 set->bits = who ? who : STANDARD_BITS;
 363                 set++;
 364
 365                 op = '+';
 366                 /* FALLTHROUGH */
 367         case '+':
 368         case '-':
 369         case 'X':
 370                 set->cmd = op;
 371                 set->bits = (who ? who : mask) & oparg;
 372                 break;
 373
 374         case 'u':
 375         case 'g':
 376         case 'o':
 377                 set->cmd = op;
 378                 if (who) {
 379                         set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
 380                                     ((who & S_IRGRP) ? CMD2_GBITS : 0) |
 381                                     ((who & S_IROTH) ? CMD2_OBITS : 0);
 382                         set->bits = (mode_t)~0;
 383                 } else {
 384                         set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
 385                         set->bits = mask;
 386                 }
 387
 388                 if (oparg == '+')
 389                         set->cmd2 |= CMD2_SET;
 390                 else if (oparg == '-')
 391                         set->cmd2 |= CMD2_CLR;
 392                 else if (oparg == '=')
 393                         set->cmd2 |= CMD2_SET|CMD2_CLR;
 394                 break;
 395         }
 396         return (set + 1);
 397 }
 398
 399 #ifdef SETMODE_DEBUG
 400 static void
 401 dumpmode(BITCMD *set)
 402 {
 403         for (; set->cmd; ++set)
 404                 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
 405                     set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
 406                     set->cmd2 & CMD2_CLR ? " CLR" : "",
 407                     set->cmd2 & CMD2_SET ? " SET" : "",
 408                     set->cmd2 & CMD2_UBITS ? " UBITS" : "",
 409                     set->cmd2 & CMD2_GBITS ? " GBITS" : "",
 410                     set->cmd2 & CMD2_OBITS ? " OBITS" : "");
 411 }
 412 #endif
 413
 414 #ifndef BUILDING_VARIANT
 415 /*
 416  * Given an array of bitcmd structures, compress by compacting consecutive
 417  * '+', '-' and 'X' commands into at most 3 commands, one of each.  The 'u',
 418  * 'g' and 'o' commands continue to be separate.  They could probably be
 419  * compacted, but it's not worth the effort.
 420  */
 421 __private_extern__ void
 422 compress_mode(BITCMD *set)
 423 {
 424         BITCMD *nset;
 425         int setbits, clrbits, Xbits, op;
 426
 427         for (nset = set;;) {
 428                 /* Copy over any 'u', 'g' and 'o' commands. */
 429                 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
 430                         *set++ = *nset++;
 431                         if (!op)
 432                                 return;
 433                 }
 434
 435                 for (setbits = clrbits = Xbits = 0;; nset++) {
 436                         if ((op = nset->cmd) == '-') {
 437                                 clrbits |= nset->bits;
 438                                 setbits &= ~nset->bits;
 439                                 Xbits &= ~nset->bits;
 440                         } else if (op == '+') {
 441                                 setbits |= nset->bits;
 442                                 clrbits &= ~nset->bits;
 443                                 Xbits &= ~nset->bits;
 444                         } else if (op == 'X')
 445                                 Xbits |= nset->bits & ~setbits;
 446                         else
 447                                 break;
 448                 }
 449                 if (clrbits) {
 450                         set->cmd = '-';
 451                         set->cmd2 = 0;
 452                         set->bits = clrbits;
 453                         set++;
 454                 }
 455                 if (setbits) {
 456                         set->cmd = '+';
 457                         set->cmd2 = 0;
 458                         set->bits = setbits;
 459                         set++;
 460                 }
 461                 if (Xbits) {
 462                         set->cmd = 'X';
 463                         set->cmd2 = 0;
 464                         set->bits = Xbits;
 465                         set++;
 466                 }
 467         }
 468 }
 469 #endif /* BUILDING_VARIANT */