1 /* $OpenBSD: setmode.c,v 1.11 2002/02/19 19:39:36 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. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94"; 43 #else 44 static char rcsid[] = "$OpenBSD: setmode.c,v 1.11 2002/02/19 19:39:36 millert Exp $"; 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include <sys/types.h> 49 #include <sys/stat.h> 50 51 #include <ctype.h> 52 #include <errno.h> 53 #include <signal.h> 54 #include <stdlib.h> 55 #include <unistd.h> 56 57 #ifdef SETMODE_DEBUG 58 #include <stdio.h> 59 #endif 60 61 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 62 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 63 64 typedef struct bitcmd { 65 char cmd; 66 char cmd2; 67 mode_t bits; 68 } BITCMD; 69 70 #define CMD2_CLR 0x01 71 #define CMD2_SET 0x02 72 #define CMD2_GBITS 0x04 73 #define CMD2_OBITS 0x08 74 #define CMD2_UBITS 0x10 75 76 static BITCMD *addcmd(BITCMD *, int, int, int, u_int); 77 static void compress_mode(BITCMD *); 78 #ifdef SETMODE_DEBUG 79 static void dumpmode(BITCMD *); 80 #endif 81 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(const void *bbox, mode_t omode) 90 { 91 register const BITCMD *set; 92 register mode_t clrval, newmode, value; 93 94 set = (const BITCMD *)bbox; 95 newmode = omode; 96 for (value = 0;; set++) 97 switch(set->cmd) { 98 /* 99 * When copying the user, group or other bits around, we "know" 100 * where the bits are in the mode so that we can do shifts to 101 * copy them around. If we don't use shifts, it gets real 102 * grundgy with lots of single bit checks and bit sets. 103 */ 104 case 'u': 105 value = (newmode & S_IRWXU) >> 6; 106 goto common; 107 108 case 'g': 109 value = (newmode & S_IRWXG) >> 3; 110 goto common; 111 112 case 'o': 113 value = newmode & S_IRWXO; 114 common: if (set->cmd2 & CMD2_CLR) { 115 clrval = 116 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 117 if (set->cmd2 & CMD2_UBITS) 118 newmode &= ~((clrval<<6) & set->bits); 119 if (set->cmd2 & CMD2_GBITS) 120 newmode &= ~((clrval<<3) & set->bits); 121 if (set->cmd2 & CMD2_OBITS) 122 newmode &= ~(clrval & set->bits); 123 } 124 if (set->cmd2 & CMD2_SET) { 125 if (set->cmd2 & CMD2_UBITS) 126 newmode |= (value<<6) & set->bits; 127 if (set->cmd2 & CMD2_GBITS) 128 newmode |= (value<<3) & set->bits; 129 if (set->cmd2 & CMD2_OBITS) 130 newmode |= value & set->bits; 131 } 132 break; 133 134 case '+': 135 newmode |= set->bits; 136 break; 137 138 case '-': 139 newmode &= ~set->bits; 140 break; 141 142 case 'X': 143 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 144 newmode |= set->bits; 145 break; 146 147 case '\0': 148 default: 149 #ifdef SETMODE_DEBUG 150 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 151 #endif 152 return (newmode); 153 } 154 } 155 156 #define ADDCMD(a, b, c, d) \ 157 if (set >= endset) { \ 158 register BITCMD *newset; \ 159 setlen += SET_LEN_INCR; \ 160 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 161 if (!newset) { \ 162 if (saveset) \ 163 free(saveset); \ 164 saveset = NULL; \ 165 return (NULL); \ 166 } \ 167 set = newset + (set - saveset); \ 168 saveset = newset; \ 169 endset = newset + (setlen - 2); \ 170 } \ 171 set = addcmd(set, (a), (b), (c), (d)) 172 173 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 174 175 void * 176 setmode(p) 177 register const char *p; 178 { 179 register int perm, who; 180 register char op; 181 BITCMD *set, *saveset, *endset; 182 sigset_t sigset, sigoset; 183 mode_t mask; 184 int equalopdone, 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(*p)) { 214 perml = strtol(p, NULL, 8); 215 if (perml < 0 || (perml & ~(STANDARD_BITS|S_ISTXT))) { 216 free(saveset); 217 return (NULL); 218 } 219 perm = (mode_t)perml; 220 while (*++p) 221 if (*p < '0' || *p > '7') { 222 free(saveset); 223 return (NULL); 224 } 225 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 226 return (saveset); 227 } 228 229 /* 230 * Build list of structures to set/clear/copy bits as described by 231 * each clause of the symbolic mode. 232 */ 233 for (;;) { 234 /* First, find out which bits might be modified. */ 235 for (who = 0;; ++p) { 236 switch (*p) { 237 case 'a': 238 who |= STANDARD_BITS; 239 break; 240 case 'u': 241 who |= S_ISUID|S_IRWXU; 242 break; 243 case 'g': 244 who |= S_ISGID|S_IRWXG; 245 break; 246 case 'o': 247 who |= S_IRWXO; 248 break; 249 default: 250 goto getop; 251 } 252 } 253 254 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 255 free(saveset); 256 return (NULL); 257 } 258 if (op == '=') 259 equalopdone = 0; 260 261 who &= ~S_ISTXT; 262 for (perm = 0, permXbits = 0;; ++p) { 263 switch (*p) { 264 case 'r': 265 perm |= S_IRUSR|S_IRGRP|S_IROTH; 266 break; 267 case 's': 268 /* 269 * If specific bits where requested and 270 * only "other" bits ignore set-id. 271 */ 272 if (who == 0 || (who & ~S_IRWXO)) 273 perm |= S_ISUID|S_ISGID; 274 break; 275 case 't': 276 /* 277 * If specific bits where requested and 278 * only "other" bits ignore sticky. 279 */ 280 if (who == 0 || (who & ~S_IRWXO)) { 281 who |= S_ISTXT; 282 perm |= S_ISTXT; 283 } 284 break; 285 case 'w': 286 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 287 break; 288 case 'X': 289 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 290 break; 291 case 'x': 292 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 293 break; 294 case 'u': 295 case 'g': 296 case 'o': 297 /* 298 * When ever we hit 'u', 'g', or 'o', we have 299 * to flush out any partial mode that we have, 300 * and then do the copying of the mode bits. 301 */ 302 if (perm) { 303 ADDCMD(op, who, perm, mask); 304 perm = 0; 305 } 306 if (op == '=') 307 equalopdone = 1; 308 if (op == '+' && permXbits) { 309 ADDCMD('X', who, permXbits, mask); 310 permXbits = 0; 311 } 312 ADDCMD(*p, who, op, mask); 313 break; 314 315 default: 316 /* 317 * Add any permissions that we haven't already 318 * done. 319 */ 320 if (perm || (op == '=' && !equalopdone)) { 321 if (op == '=') 322 equalopdone = 1; 323 ADDCMD(op, who, perm, mask); 324 perm = 0; 325 } 326 if (permXbits) { 327 ADDCMD('X', who, permXbits, mask); 328 permXbits = 0; 329 } 330 goto apply; 331 } 332 } 333 334 apply: if (!*p) 335 break; 336 if (*p != ',') 337 goto getop; 338 ++p; 339 } 340 set->cmd = 0; 341 #ifdef SETMODE_DEBUG 342 (void)printf("Before compress_mode()\n"); 343 dumpmode(saveset); 344 #endif 345 compress_mode(saveset); 346 #ifdef SETMODE_DEBUG 347 (void)printf("After compress_mode()\n"); 348 dumpmode(saveset); 349 #endif 350 return (saveset); 351 } 352 353 static BITCMD * 354 addcmd(set, op, who, oparg, mask) 355 BITCMD *set; 356 register int oparg, who; 357 register int op; 358 u_int mask; 359 { 360 switch (op) { 361 case '=': 362 set->cmd = '-'; 363 set->bits = who ? who : STANDARD_BITS; 364 set++; 365 366 op = '+'; 367 /* FALLTHROUGH */ 368 case '+': 369 case '-': 370 case 'X': 371 set->cmd = op; 372 set->bits = (who ? who : mask) & oparg; 373 break; 374 375 case 'u': 376 case 'g': 377 case 'o': 378 set->cmd = op; 379 if (who) { 380 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 381 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 382 ((who & S_IROTH) ? CMD2_OBITS : 0); 383 set->bits = (mode_t)~0; 384 } else { 385 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 386 set->bits = mask; 387 } 388 389 if (oparg == '+') 390 set->cmd2 |= CMD2_SET; 391 else if (oparg == '-') 392 set->cmd2 |= CMD2_CLR; 393 else if (oparg == '=') 394 set->cmd2 |= CMD2_SET|CMD2_CLR; 395 break; 396 } 397 return (set + 1); 398 } 399 400 #ifdef SETMODE_DEBUG 401 static void 402 dumpmode(set) 403 register BITCMD *set; 404 { 405 for (; set->cmd; ++set) 406 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 407 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 408 set->cmd2 & CMD2_CLR ? " CLR" : "", 409 set->cmd2 & CMD2_SET ? " SET" : "", 410 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 411 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 412 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 413 } 414 #endif 415 416 /* 417 * Given an array of bitcmd structures, compress by compacting consecutive 418 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 419 * 'g' and 'o' commands continue to be separate. They could probably be 420 * compacted, but it's not worth the effort. 421 */ 422 static void 423 compress_mode(set) 424 register BITCMD *set; 425 { 426 register BITCMD *nset; 427 register int setbits, clrbits, Xbits, op; 428 429 for (nset = set;;) { 430 /* Copy over any 'u', 'g' and 'o' commands. */ 431 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 432 *set++ = *nset++; 433 if (!op) 434 return; 435 } 436 437 for (setbits = clrbits = Xbits = 0;; nset++) { 438 if ((op = nset->cmd) == '-') { 439 clrbits |= nset->bits; 440 setbits &= ~nset->bits; 441 Xbits &= ~nset->bits; 442 } else if (op == '+') { 443 setbits |= nset->bits; 444 clrbits &= ~nset->bits; 445 Xbits &= ~nset->bits; 446 } else if (op == 'X') 447 Xbits |= nset->bits & ~setbits; 448 else 449 break; 450 } 451 if (clrbits) { 452 set->cmd = '-'; 453 set->cmd2 = 0; 454 set->bits = clrbits; 455 set++; 456 } 457 if (setbits) { 458 set->cmd = '+'; 459 set->cmd2 = 0; 460 set->bits = setbits; 461 set++; 462 } 463 if (Xbits) { 464 set->cmd = 'X'; 465 set->cmd2 = 0; 466 set->bits = Xbits; 467 set++; 468 } 469 } 470 } 471