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 * @(#)setmode.c 8.2 (Berkeley) 3/25/94 37 * $FreeBSD: src/lib/libc/gen/setmode.c,v 1.5.2.1 2001/03/05 09:34:10 obrien Exp $ 38 * $DragonFly: src/lib/libc/gen/setmode.c,v 1.2 2003/06/17 04:26:42 dillon Exp $ 39 */ 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 44 #include <ctype.h> 45 #include <signal.h> 46 #include <stddef.h> 47 #include <stdlib.h> 48 49 #ifdef SETMODE_DEBUG 50 #include <stdio.h> 51 #endif 52 53 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 54 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 55 56 typedef struct bitcmd { 57 char cmd; 58 char cmd2; 59 mode_t bits; 60 } BITCMD; 61 62 #define CMD2_CLR 0x01 63 #define CMD2_SET 0x02 64 #define CMD2_GBITS 0x04 65 #define CMD2_OBITS 0x08 66 #define CMD2_UBITS 0x10 67 68 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 69 static void compress_mode __P((BITCMD *)); 70 #ifdef SETMODE_DEBUG 71 static void dumpmode __P((BITCMD *)); 72 #endif 73 74 /* 75 * Given the old mode and an array of bitcmd structures, apply the operations 76 * described in the bitcmd structures to the old mode, and return the new mode. 77 * Note that there is no '=' command; a strict assignment is just a '-' (clear 78 * bits) followed by a '+' (set bits). 79 */ 80 mode_t 81 getmode(bbox, omode) 82 void *bbox; 83 mode_t omode; 84 { 85 register BITCMD *set; 86 register mode_t clrval, newmode, value; 87 88 set = (BITCMD *)bbox; 89 newmode = omode; 90 for (value = 0;; set++) 91 switch(set->cmd) { 92 /* 93 * When copying the user, group or other bits around, we "know" 94 * where the bits are in the mode so that we can do shifts to 95 * copy them around. If we don't use shifts, it gets real 96 * grundgy with lots of single bit checks and bit sets. 97 */ 98 case 'u': 99 value = (newmode & S_IRWXU) >> 6; 100 goto common; 101 102 case 'g': 103 value = (newmode & S_IRWXG) >> 3; 104 goto common; 105 106 case 'o': 107 value = newmode & S_IRWXO; 108 common: if (set->cmd2 & CMD2_CLR) { 109 clrval = 110 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 111 if (set->cmd2 & CMD2_UBITS) 112 newmode &= ~((clrval<<6) & set->bits); 113 if (set->cmd2 & CMD2_GBITS) 114 newmode &= ~((clrval<<3) & set->bits); 115 if (set->cmd2 & CMD2_OBITS) 116 newmode &= ~(clrval & set->bits); 117 } 118 if (set->cmd2 & CMD2_SET) { 119 if (set->cmd2 & CMD2_UBITS) 120 newmode |= (value<<6) & set->bits; 121 if (set->cmd2 & CMD2_GBITS) 122 newmode |= (value<<3) & set->bits; 123 if (set->cmd2 & CMD2_OBITS) 124 newmode |= value & set->bits; 125 } 126 break; 127 128 case '+': 129 newmode |= set->bits; 130 break; 131 132 case '-': 133 newmode &= ~set->bits; 134 break; 135 136 case 'X': 137 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 138 newmode |= set->bits; 139 break; 140 141 case '\0': 142 default: 143 #ifdef SETMODE_DEBUG 144 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 145 #endif 146 return (newmode); 147 } 148 } 149 150 #define ADDCMD(a, b, c, d) \ 151 if (set >= endset) { \ 152 register BITCMD *newset; \ 153 setlen += SET_LEN_INCR; \ 154 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 155 if (!saveset) \ 156 return (NULL); \ 157 set = newset + (set - saveset); \ 158 saveset = newset; \ 159 endset = newset + (setlen - 2); \ 160 } \ 161 set = addcmd(set, (a), (b), (c), (d)) 162 163 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 164 165 void * 166 setmode(p) 167 register char *p; 168 { 169 register int perm, who; 170 register char op; 171 BITCMD *set, *saveset, *endset; 172 sigset_t sigset, sigoset; 173 mode_t mask; 174 int equalopdone=0, permXbits, setlen; 175 176 if (!*p) 177 return (NULL); 178 179 /* 180 * Get a copy of the mask for the permissions that are mask relative. 181 * Flip the bits, we want what's not set. Since it's possible that 182 * the caller is opening files inside a signal handler, protect them 183 * as best we can. 184 */ 185 sigfillset(&sigset); 186 (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset); 187 (void)umask(mask = umask(0)); 188 mask = ~mask; 189 (void)sigprocmask(SIG_SETMASK, &sigoset, NULL); 190 191 setlen = SET_LEN + 2; 192 193 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 194 return (NULL); 195 saveset = set; 196 endset = set + (setlen - 2); 197 198 /* 199 * If an absolute number, get it and return; disallow non-octal digits 200 * or illegal bits. 201 */ 202 if (isdigit((unsigned char)*p)) { 203 perm = (mode_t)strtol(p, NULL, 8); 204 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 205 free(saveset); 206 return (NULL); 207 } 208 while (*++p) 209 if (*p < '0' || *p > '7') { 210 free(saveset); 211 return (NULL); 212 } 213 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 214 return (saveset); 215 } 216 217 /* 218 * Build list of structures to set/clear/copy bits as described by 219 * each clause of the symbolic mode. 220 */ 221 for (;;) { 222 /* First, find out which bits might be modified. */ 223 for (who = 0;; ++p) { 224 switch (*p) { 225 case 'a': 226 who |= STANDARD_BITS; 227 break; 228 case 'u': 229 who |= S_ISUID|S_IRWXU; 230 break; 231 case 'g': 232 who |= S_ISGID|S_IRWXG; 233 break; 234 case 'o': 235 who |= S_IRWXO; 236 break; 237 default: 238 goto getop; 239 } 240 } 241 242 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 243 free(saveset); 244 return (NULL); 245 } 246 if (op == '=') 247 equalopdone = 0; 248 249 who &= ~S_ISTXT; 250 for (perm = 0, permXbits = 0;; ++p) { 251 switch (*p) { 252 case 'r': 253 perm |= S_IRUSR|S_IRGRP|S_IROTH; 254 break; 255 case 's': 256 /* If only "other" bits ignore set-id. */ 257 if (!who || who & ~S_IRWXO) 258 perm |= S_ISUID|S_ISGID; 259 break; 260 case 't': 261 /* If only "other" bits ignore sticky. */ 262 if (!who || who & ~S_IRWXO) { 263 who |= S_ISTXT; 264 perm |= S_ISTXT; 265 } 266 break; 267 case 'w': 268 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 269 break; 270 case 'X': 271 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 272 break; 273 case 'x': 274 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 275 break; 276 case 'u': 277 case 'g': 278 case 'o': 279 /* 280 * When ever we hit 'u', 'g', or 'o', we have 281 * to flush out any partial mode that we have, 282 * and then do the copying of the mode bits. 283 */ 284 if (perm) { 285 ADDCMD(op, who, perm, mask); 286 perm = 0; 287 } 288 if (op == '=') 289 equalopdone = 1; 290 if (op == '+' && permXbits) { 291 ADDCMD('X', who, permXbits, mask); 292 permXbits = 0; 293 } 294 ADDCMD(*p, who, op, mask); 295 break; 296 297 default: 298 /* 299 * Add any permissions that we haven't already 300 * done. 301 */ 302 if (perm || (op == '=' && !equalopdone)) { 303 if (op == '=') 304 equalopdone = 1; 305 ADDCMD(op, who, perm, mask); 306 perm = 0; 307 } 308 if (permXbits) { 309 ADDCMD('X', who, permXbits, mask); 310 permXbits = 0; 311 } 312 goto apply; 313 } 314 } 315 316 apply: if (!*p) 317 break; 318 if (*p != ',') 319 goto getop; 320 ++p; 321 } 322 set->cmd = 0; 323 #ifdef SETMODE_DEBUG 324 (void)printf("Before compress_mode()\n"); 325 dumpmode(saveset); 326 #endif 327 compress_mode(saveset); 328 #ifdef SETMODE_DEBUG 329 (void)printf("After compress_mode()\n"); 330 dumpmode(saveset); 331 #endif 332 return (saveset); 333 } 334 335 static BITCMD * 336 addcmd(set, op, who, oparg, mask) 337 BITCMD *set; 338 register int oparg, who; 339 register int op; 340 u_int mask; 341 { 342 switch (op) { 343 case '=': 344 set->cmd = '-'; 345 set->bits = who ? who : STANDARD_BITS; 346 set++; 347 348 op = '+'; 349 /* FALLTHROUGH */ 350 case '+': 351 case '-': 352 case 'X': 353 set->cmd = op; 354 set->bits = (who ? who : mask) & oparg; 355 break; 356 357 case 'u': 358 case 'g': 359 case 'o': 360 set->cmd = op; 361 if (who) { 362 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 363 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 364 ((who & S_IROTH) ? CMD2_OBITS : 0); 365 set->bits = ~0; 366 } else { 367 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 368 set->bits = mask; 369 } 370 371 if (oparg == '+') 372 set->cmd2 |= CMD2_SET; 373 else if (oparg == '-') 374 set->cmd2 |= CMD2_CLR; 375 else if (oparg == '=') 376 set->cmd2 |= CMD2_SET|CMD2_CLR; 377 break; 378 } 379 return (set + 1); 380 } 381 382 #ifdef SETMODE_DEBUG 383 static void 384 dumpmode(set) 385 register BITCMD *set; 386 { 387 for (; set->cmd; ++set) 388 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 389 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 390 set->cmd2 & CMD2_CLR ? " CLR" : "", 391 set->cmd2 & CMD2_SET ? " SET" : "", 392 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 393 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 394 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 395 } 396 #endif 397 398 /* 399 * Given an array of bitcmd structures, compress by compacting consecutive 400 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 401 * 'g' and 'o' commands continue to be separate. They could probably be 402 * compacted, but it's not worth the effort. 403 */ 404 static void 405 compress_mode(set) 406 register BITCMD *set; 407 { 408 register BITCMD *nset; 409 register int setbits, clrbits, Xbits, op; 410 411 for (nset = set;;) { 412 /* Copy over any 'u', 'g' and 'o' commands. */ 413 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 414 *set++ = *nset++; 415 if (!op) 416 return; 417 } 418 419 for (setbits = clrbits = Xbits = 0;; nset++) { 420 if ((op = nset->cmd) == '-') { 421 clrbits |= nset->bits; 422 setbits &= ~nset->bits; 423 Xbits &= ~nset->bits; 424 } else if (op == '+') { 425 setbits |= nset->bits; 426 clrbits &= ~nset->bits; 427 Xbits &= ~nset->bits; 428 } else if (op == 'X') 429 Xbits |= nset->bits & ~setbits; 430 else 431 break; 432 } 433 if (clrbits) { 434 set->cmd = '-'; 435 set->cmd2 = 0; 436 set->bits = clrbits; 437 set++; 438 } 439 if (setbits) { 440 set->cmd = '+'; 441 set->cmd2 = 0; 442 set->bits = setbits; 443 set++; 444 } 445 if (Xbits) { 446 set->cmd = 'X'; 447 set->cmd2 = 0; 448 set->bits = Xbits; 449 set++; 450 } 451 } 452 } 453