1 /* $OpenBSD: setmode.c,v 1.12 2003/06/02 20:18:34 millert Exp $ */ 2 /* $NetBSD: setmode.c,v 1.15 1997/02/07 22:21:06 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1989, 1993, 1994 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Dave Borman at Cray Research, Inc. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94"; 39 #else 40 static char rcsid[] = "$OpenBSD: setmode.c,v 1.12 2003/06/02 20:18:34 millert Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 47 #include <ctype.h> 48 #include <errno.h> 49 #include <signal.h> 50 #include <stdlib.h> 51 #include <unistd.h> 52 53 #ifdef SETMODE_DEBUG 54 #include <stdio.h> 55 #endif 56 57 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 58 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 59 60 typedef struct bitcmd { 61 char cmd; 62 char cmd2; 63 mode_t bits; 64 } BITCMD; 65 66 #define CMD2_CLR 0x01 67 #define CMD2_SET 0x02 68 #define CMD2_GBITS 0x04 69 #define CMD2_OBITS 0x08 70 #define CMD2_UBITS 0x10 71 72 static BITCMD *addcmd(BITCMD *, int, int, int, u_int); 73 static void compress_mode(BITCMD *); 74 #ifdef SETMODE_DEBUG 75 static void dumpmode(BITCMD *); 76 #endif 77 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 register const BITCMD *set; 88 register 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 } 151 152 #define ADDCMD(a, b, c, d) \ 153 if (set >= endset) { \ 154 register BITCMD *newset; \ 155 setlen += SET_LEN_INCR; \ 156 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 157 if (!newset) { \ 158 if (saveset) \ 159 free(saveset); \ 160 saveset = NULL; \ 161 return (NULL); \ 162 } \ 163 set = newset + (set - saveset); \ 164 saveset = newset; \ 165 endset = newset + (setlen - 2); \ 166 } \ 167 set = addcmd(set, (a), (b), (c), (d)) 168 169 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 170 171 void * 172 setmode(p) 173 register const char *p; 174 { 175 register int perm, who; 176 register char op; 177 BITCMD *set, *saveset, *endset; 178 sigset_t sigset, sigoset; 179 mode_t mask; 180 int equalopdone, permXbits, setlen; 181 long perml; 182 183 if (!*p) 184 return (NULL); 185 186 /* 187 * Get a copy of the mask for the permissions that are mask relative. 188 * Flip the bits, we want what's not set. Since it's possible that 189 * the caller is opening files inside a signal handler, protect them 190 * as best we can. 191 */ 192 sigfillset(&sigset); 193 (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset); 194 (void)umask(mask = umask(0)); 195 mask = ~mask; 196 (void)sigprocmask(SIG_SETMASK, &sigoset, NULL); 197 198 setlen = SET_LEN + 2; 199 200 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 201 return (NULL); 202 saveset = set; 203 endset = set + (setlen - 2); 204 205 /* 206 * If an absolute number, get it and return; disallow non-octal digits 207 * or illegal bits. 208 */ 209 if (isdigit(*p)) { 210 perml = strtol(p, NULL, 8); 211 if (perml < 0 || (perml & ~(STANDARD_BITS|S_ISTXT))) { 212 free(saveset); 213 return (NULL); 214 } 215 perm = (mode_t)perml; 216 while (*++p) 217 if (*p < '0' || *p > '7') { 218 free(saveset); 219 return (NULL); 220 } 221 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 222 return (saveset); 223 } 224 225 /* 226 * Build list of structures to set/clear/copy bits as described by 227 * each clause of the symbolic mode. 228 */ 229 for (;;) { 230 /* First, find out which bits might be modified. */ 231 for (who = 0;; ++p) { 232 switch (*p) { 233 case 'a': 234 who |= STANDARD_BITS; 235 break; 236 case 'u': 237 who |= S_ISUID|S_IRWXU; 238 break; 239 case 'g': 240 who |= S_ISGID|S_IRWXG; 241 break; 242 case 'o': 243 who |= S_IRWXO; 244 break; 245 default: 246 goto getop; 247 } 248 } 249 250 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 251 free(saveset); 252 return (NULL); 253 } 254 if (op == '=') 255 equalopdone = 0; 256 257 who &= ~S_ISTXT; 258 for (perm = 0, permXbits = 0;; ++p) { 259 switch (*p) { 260 case 'r': 261 perm |= S_IRUSR|S_IRGRP|S_IROTH; 262 break; 263 case 's': 264 /* 265 * If specific bits where requested and 266 * only "other" bits ignore set-id. 267 */ 268 if (who == 0 || (who & ~S_IRWXO)) 269 perm |= S_ISUID|S_ISGID; 270 break; 271 case 't': 272 /* 273 * If specific bits where requested and 274 * only "other" bits ignore sticky. 275 */ 276 if (who == 0 || (who & ~S_IRWXO)) { 277 who |= S_ISTXT; 278 perm |= S_ISTXT; 279 } 280 break; 281 case 'w': 282 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 283 break; 284 case 'X': 285 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 286 break; 287 case 'x': 288 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 289 break; 290 case 'u': 291 case 'g': 292 case 'o': 293 /* 294 * When ever we hit 'u', 'g', or 'o', we have 295 * to flush out any partial mode that we have, 296 * and then do the copying of the mode bits. 297 */ 298 if (perm) { 299 ADDCMD(op, who, perm, mask); 300 perm = 0; 301 } 302 if (op == '=') 303 equalopdone = 1; 304 if (op == '+' && permXbits) { 305 ADDCMD('X', who, permXbits, mask); 306 permXbits = 0; 307 } 308 ADDCMD(*p, who, op, mask); 309 break; 310 311 default: 312 /* 313 * Add any permissions that we haven't already 314 * done. 315 */ 316 if (perm || (op == '=' && !equalopdone)) { 317 if (op == '=') 318 equalopdone = 1; 319 ADDCMD(op, who, perm, mask); 320 perm = 0; 321 } 322 if (permXbits) { 323 ADDCMD('X', who, permXbits, mask); 324 permXbits = 0; 325 } 326 goto apply; 327 } 328 } 329 330 apply: if (!*p) 331 break; 332 if (*p != ',') 333 goto getop; 334 ++p; 335 } 336 set->cmd = 0; 337 #ifdef SETMODE_DEBUG 338 (void)printf("Before compress_mode()\n"); 339 dumpmode(saveset); 340 #endif 341 compress_mode(saveset); 342 #ifdef SETMODE_DEBUG 343 (void)printf("After compress_mode()\n"); 344 dumpmode(saveset); 345 #endif 346 return (saveset); 347 } 348 349 static BITCMD * 350 addcmd(set, op, who, oparg, mask) 351 BITCMD *set; 352 register int oparg, who; 353 register int op; 354 u_int mask; 355 { 356 switch (op) { 357 case '=': 358 set->cmd = '-'; 359 set->bits = who ? who : STANDARD_BITS; 360 set++; 361 362 op = '+'; 363 /* FALLTHROUGH */ 364 case '+': 365 case '-': 366 case 'X': 367 set->cmd = op; 368 set->bits = (who ? who : mask) & oparg; 369 break; 370 371 case 'u': 372 case 'g': 373 case 'o': 374 set->cmd = op; 375 if (who) { 376 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 377 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 378 ((who & S_IROTH) ? CMD2_OBITS : 0); 379 set->bits = (mode_t)~0; 380 } else { 381 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 382 set->bits = mask; 383 } 384 385 if (oparg == '+') 386 set->cmd2 |= CMD2_SET; 387 else if (oparg == '-') 388 set->cmd2 |= CMD2_CLR; 389 else if (oparg == '=') 390 set->cmd2 |= CMD2_SET|CMD2_CLR; 391 break; 392 } 393 return (set + 1); 394 } 395 396 #ifdef SETMODE_DEBUG 397 static void 398 dumpmode(set) 399 register BITCMD *set; 400 { 401 for (; set->cmd; ++set) 402 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 403 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 404 set->cmd2 & CMD2_CLR ? " CLR" : "", 405 set->cmd2 & CMD2_SET ? " SET" : "", 406 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 407 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 408 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 409 } 410 #endif 411 412 /* 413 * Given an array of bitcmd structures, compress by compacting consecutive 414 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 415 * 'g' and 'o' commands continue to be separate. They could probably be 416 * compacted, but it's not worth the effort. 417 */ 418 static void 419 compress_mode(set) 420 register BITCMD *set; 421 { 422 register BITCMD *nset; 423 register int setbits, clrbits, Xbits, op; 424 425 for (nset = set;;) { 426 /* Copy over any 'u', 'g' and 'o' commands. */ 427 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 428 *set++ = *nset++; 429 if (!op) 430 return; 431 } 432 433 for (setbits = clrbits = Xbits = 0;; nset++) { 434 if ((op = nset->cmd) == '-') { 435 clrbits |= nset->bits; 436 setbits &= ~nset->bits; 437 Xbits &= ~nset->bits; 438 } else if (op == '+') { 439 setbits |= nset->bits; 440 clrbits &= ~nset->bits; 441 Xbits &= ~nset->bits; 442 } else if (op == 'X') 443 Xbits |= nset->bits & ~setbits; 444 else 445 break; 446 } 447 if (clrbits) { 448 set->cmd = '-'; 449 set->cmd2 = 0; 450 set->bits = clrbits; 451 set++; 452 } 453 if (setbits) { 454 set->cmd = '+'; 455 set->cmd2 = 0; 456 set->bits = setbits; 457 set++; 458 } 459 if (Xbits) { 460 set->cmd = 'X'; 461 set->cmd2 = 0; 462 set->bits = Xbits; 463 set++; 464 } 465 } 466 } 467