1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 /*static char *sccsid = "from: @(#)setmode.c 5.6 (Berkeley) 5/27/91";*/ 36 static char *rcsid = "$Id: setmode.c,v 1.6 1994/02/10 23:36:59 cgd Exp $"; 37 #endif /* LIBC_SCCS and not lint */ 38 39 #include <sys/types.h> 40 #include <sys/stat.h> 41 #include <signal.h> 42 #include <errno.h> 43 #include <stddef.h> 44 #ifdef SETMODE_DEBUG 45 #include <stdio.h> 46 #endif 47 #include <stdlib.h> 48 #include <ctype.h> 49 50 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 51 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 52 53 typedef struct bitcmd { 54 char cmd; 55 char cmd2; 56 mode_t bits; 57 } BITCMD; 58 59 #define CMD2_CLR 0x01 60 #define CMD2_SET 0x02 61 #define CMD2_GBITS 0x04 62 #define CMD2_OBITS 0x08 63 #define CMD2_UBITS 0x10 64 65 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 66 static int compress_mode __P((BITCMD *)); 67 #ifdef SETMODE_DEBUG 68 static void dumpmode __P((BITCMD *)); 69 #endif 70 71 /* 72 * Given the old mode and an array of bitcmd structures, apply the operations 73 * described in the bitcmd structures to the old mode, and return the new mode. 74 * Note that there is no '=' command; a strict assignment is just a '-' (clear 75 * bits) followed by a '+' (set bits). 76 */ 77 mode_t 78 getmode(bbox, omode) 79 void *bbox; 80 mode_t omode; 81 { 82 register BITCMD *set; 83 register mode_t newmode, value; 84 85 set = (BITCMD *)bbox; 86 newmode = omode; 87 for (value = 0;; set++) 88 switch(set->cmd) { 89 /* 90 * When copying the user, group or other bits around, we "know" 91 * where the bits are in the mode so that we can do shifts to 92 * copy them around. If we don't use shifts, it gets real 93 * grundgy with lots of single bit checks and bit sets. 94 */ 95 case 'u': 96 value = (newmode & S_IRWXU) >> 6; 97 goto common; 98 99 case 'g': 100 value = (newmode & S_IRWXG) >> 3; 101 goto common; 102 103 case 'o': 104 value = newmode & S_IRWXO; 105 common: if (set->cmd2 & CMD2_CLR) { 106 if (set->cmd2 & CMD2_UBITS) 107 newmode &= ~(S_IRWXU & set->bits); 108 if (set->cmd2 & CMD2_GBITS) 109 newmode &= ~(S_IRWXG & set->bits); 110 if (set->cmd2 & CMD2_OBITS) 111 newmode &= ~(S_IRWXO & set->bits); 112 } 113 if (set->cmd2 & CMD2_SET) { 114 if (set->cmd2 & CMD2_UBITS) 115 newmode |= (value<<6) & set->bits; 116 if (set->cmd2 & CMD2_GBITS) 117 newmode |= (value<<3) & set->bits; 118 if (set->cmd2 & CMD2_OBITS) 119 newmode |= value & set->bits; 120 } 121 break; 122 123 case '+': 124 newmode |= set->bits; 125 break; 126 127 case '-': 128 newmode &= ~set->bits; 129 break; 130 131 case 'X': 132 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 133 newmode |= set->bits; 134 break; 135 136 case '\0': 137 default: 138 #ifdef SETMODE_DEBUG 139 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 140 #endif 141 return (newmode); 142 } 143 } 144 145 #define ADDCMD(a, b, c, d) \ 146 if (set >= endset) { \ 147 register BITCMD *newset; \ 148 setlen += SET_LEN_INCR; \ 149 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 150 if (!saveset) \ 151 return (NULL); \ 152 set = newset + (set - saveset); \ 153 saveset = newset; \ 154 endset = newset + (setlen - 2); \ 155 } \ 156 set = addcmd(set, (a), (b), (c), (d)) 157 158 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 159 160 void * 161 setmode(p) 162 register char *p; 163 { 164 register int perm, who; 165 register char op; 166 BITCMD *set, *saveset, *endset; 167 sigset_t sigset, sigoset; 168 mode_t mask; 169 int permXbits, setlen; 170 171 if (!*p) 172 return (NULL); 173 174 /* 175 * Get a copy of the mask for the permissions that are mask relative. 176 * Flip the bits, we want what's not set. Since it's possible that 177 * the caller is opening files inside a signal handler, protect them 178 * as best we can. 179 */ 180 sigfillset(&sigset); 181 (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset); 182 (void)umask(mask = umask(0)); 183 mask = ~mask; 184 (void)sigprocmask(SIG_SETMASK, &sigoset, NULL); 185 186 setlen = SET_LEN + 2; 187 188 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 189 return (NULL); 190 saveset = set; 191 endset = set + (setlen - 2); 192 193 /* 194 * If an absolute number, get it and return; disallow non-octal digits 195 * or illegal bits. 196 */ 197 if (isdigit(*p)) { 198 perm = (mode_t)strtol(p, (char **)0, 8); 199 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 200 free(saveset); 201 return (NULL); 202 } 203 while (*++p) 204 if (*p < '0' || *p > '7') { 205 free(saveset); 206 return (NULL); 207 } 208 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 209 return (saveset); 210 } 211 212 /* 213 * Build list of structures to set/clear/copy bits as described by 214 * each clause of the symbolic mode. 215 */ 216 for (;;) { 217 /* First, find out which bits might be modified. */ 218 for (who = 0;; ++p) { 219 switch (*p) { 220 case 'a': 221 who |= STANDARD_BITS; 222 break; 223 case 'u': 224 who |= S_ISUID|S_IRWXU; 225 break; 226 case 'g': 227 who |= S_ISGID|S_IRWXG; 228 break; 229 case 'o': 230 who |= S_IRWXO; 231 break; 232 default: 233 goto getop; 234 } 235 } 236 237 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 238 free(saveset); 239 return (NULL); 240 } 241 242 who &= ~S_ISTXT; 243 for (perm = 0, permXbits = 0;; ++p) { 244 switch (*p) { 245 case 'r': 246 perm |= S_IRUSR|S_IRGRP|S_IROTH; 247 break; 248 case 's': 249 /* If only "other" bits ignore set-id. */ 250 if (who & ~S_IRWXO) 251 perm |= S_ISUID|S_ISGID; 252 break; 253 case 't': 254 /* If only "other" bits ignore sticky. */ 255 if (who & ~S_IRWXO) { 256 who |= S_ISTXT; 257 perm |= S_ISTXT; 258 } 259 break; 260 case 'w': 261 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 262 break; 263 case 'X': 264 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 265 break; 266 case 'x': 267 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 268 break; 269 case 'u': 270 case 'g': 271 case 'o': 272 /* 273 * When ever we hit 'u', 'g', or 'o', we have 274 * to flush out any partial mode that we have, 275 * and then do the copying of the mode bits. 276 */ 277 if (perm || op == '=') { 278 ADDCMD(op, who, perm, mask); 279 perm = 0; 280 } 281 if (op == '+' && permXbits) { 282 ADDCMD('X', who, permXbits, mask); 283 permXbits = 0; 284 } 285 ADDCMD(*p, who, op, mask); 286 break; 287 288 default: 289 /* 290 * Add any permissions that we haven't already 291 * done. 292 */ 293 if (perm || op == '=') { 294 ADDCMD(op, who, perm, mask); 295 perm = 0; 296 } 297 if (permXbits) { 298 ADDCMD('X', who, permXbits, mask); 299 permXbits = 0; 300 } 301 goto apply; 302 } 303 } 304 305 apply: if (!*p) 306 break; 307 if (*p != ',') 308 goto getop; 309 ++p; 310 } 311 set->cmd = 0; 312 #ifdef SETMODE_DEBUG 313 (void)printf("Before compress_mode()\n"); 314 dumpmode(saveset); 315 #endif 316 compress_mode(saveset); 317 #ifdef SETMODE_DEBUG 318 (void)printf("After compress_mode()\n"); 319 dumpmode(saveset); 320 #endif 321 return (saveset); 322 } 323 324 static BITCMD * 325 addcmd(set, op, who, oparg, mask) 326 BITCMD *set; 327 register int oparg, who; 328 register int op; 329 u_int mask; 330 { 331 switch (op) { 332 case '+': 333 case 'X': 334 set->cmd = op; 335 set->bits = (who ? who : mask) & oparg; 336 break; 337 338 case '-': 339 set->cmd = '-'; 340 set->bits = (who ? who : (S_IRWXU|S_IRWXG|S_IRWXO)) & oparg; 341 break; 342 343 case '=': 344 set->cmd = '-'; 345 if (!who) { 346 set->bits = STANDARD_BITS; 347 who = mask; 348 } else 349 set->bits = who; 350 set++; 351 352 set->cmd = '+'; 353 set->bits = who & oparg; 354 break; 355 case 'u': 356 case 'g': 357 case 'o': 358 set->cmd = op; 359 if (who) { 360 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 361 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 362 ((who & S_IROTH) ? CMD2_OBITS : 0); 363 set->bits = ~0; 364 } else { 365 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 366 set->bits = mask; 367 } 368 369 if (oparg == '+') 370 set->cmd2 |= CMD2_SET; 371 else if (oparg == '-') 372 set->cmd2 |= CMD2_CLR; 373 else if (oparg == '=') 374 set->cmd2 |= CMD2_SET|CMD2_CLR; 375 break; 376 } 377 return (set + 1); 378 } 379 380 #ifdef SETMODE_DEBUG 381 static void 382 dumpmode(set) 383 register BITCMD *set; 384 { 385 for (; set->cmd; ++set) 386 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 387 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 388 set->cmd2 & CMD2_CLR ? " CLR" : "", 389 set->cmd2 & CMD2_SET ? " SET" : "", 390 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 391 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 392 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 393 } 394 #endif 395 396 /* 397 * Given an array of bitcmd structures, compress by compacting consecutive 398 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 399 * 'g' and 'o' commands continue to be separate. They could probably be 400 * compacted, but it's not worth the effort. 401 */ 402 static int 403 compress_mode(set) 404 register BITCMD *set; 405 { 406 register BITCMD *nset; 407 register int setbits, clrbits, Xbits, op; 408 409 for (nset = set;;) { 410 /* Copy over any 'u', 'g' and 'o' commands. */ 411 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 412 *set++ = *nset++; 413 if (!op) 414 return; 415 } 416 417 for (setbits = clrbits = Xbits = 0;; nset++) { 418 if ((op = nset->cmd) == '-') { 419 clrbits |= nset->bits; 420 setbits &= ~nset->bits; 421 Xbits &= ~nset->bits; 422 } else if (op == '+') { 423 setbits |= nset->bits; 424 clrbits &= ~nset->bits; 425 Xbits &= ~nset->bits; 426 } else if (op == 'X') 427 Xbits |= nset->bits & ~setbits; 428 else 429 break; 430 } 431 if (clrbits) { 432 set->cmd = '-'; 433 set->cmd2 = 0; 434 set->bits = clrbits; 435 set++; 436 } 437 if (setbits) { 438 set->cmd = '+'; 439 set->cmd2 = 0; 440 set->bits = setbits; 441 set++; 442 } 443 if (Xbits) { 444 set->cmd = 'X'; 445 set->cmd2 = 0; 446 set->bits = Xbits; 447 set++; 448 } 449 } 450 } 451