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 1.5 2005/01/31 22:29:15 dillon Exp $ 39 */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 45 #include <ctype.h> 46 #include <signal.h> 47 #include <stddef.h> 48 #include <stdlib.h> 49 50 #ifdef SETMODE_DEBUG 51 #include <stdio.h> 52 #endif 53 #include "un-namespace.h" 54 55 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 56 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 57 58 typedef struct bitcmd { 59 char cmd; 60 char cmd2; 61 mode_t bits; 62 } BITCMD; 63 64 #define CMD2_CLR 0x01 65 #define CMD2_SET 0x02 66 #define CMD2_GBITS 0x04 67 #define CMD2_OBITS 0x08 68 #define CMD2_UBITS 0x10 69 70 static BITCMD *addcmd (BITCMD *, int, int, int, u_int); 71 static void compress_mode (BITCMD *); 72 #ifdef SETMODE_DEBUG 73 static void dumpmode (BITCMD *); 74 #endif 75 76 /* 77 * Given the old mode and an array of bitcmd structures, apply the operations 78 * described in the bitcmd structures to the old mode, and return the new mode. 79 * Note that there is no '=' command; a strict assignment is just a '-' (clear 80 * bits) followed by a '+' (set bits). 81 */ 82 mode_t 83 getmode(bbox, omode) 84 void *bbox; 85 mode_t omode; 86 { 87 BITCMD *set; 88 mode_t clrval, newmode, value; 89 90 set = (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 BITCMD *newset; \ 155 setlen += SET_LEN_INCR; \ 156 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 157 if (!saveset) \ 158 return (NULL); \ 159 set = newset + (set - saveset); \ 160 saveset = newset; \ 161 endset = newset + (setlen - 2); \ 162 } \ 163 set = addcmd(set, (a), (b), (c), (d)) 164 165 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 166 167 void * 168 setmode(p) 169 char *p; 170 { 171 int perm, who; 172 char op; 173 BITCMD *set, *saveset, *endset; 174 sigset_t sigset, sigoset; 175 mode_t mask; 176 int equalopdone=0, permXbits, setlen; 177 178 if (!*p) 179 return (NULL); 180 181 /* 182 * Get a copy of the mask for the permissions that are mask relative. 183 * Flip the bits, we want what's not set. Since it's possible that 184 * the caller is opening files inside a signal handler, protect them 185 * as best we can. 186 */ 187 sigfillset(&sigset); 188 (void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset); 189 (void)umask(mask = umask(0)); 190 mask = ~mask; 191 (void)_sigprocmask(SIG_SETMASK, &sigoset, NULL); 192 193 setlen = SET_LEN + 2; 194 195 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 196 return (NULL); 197 saveset = set; 198 endset = set + (setlen - 2); 199 200 /* 201 * If an absolute number, get it and return; disallow non-octal digits 202 * or illegal bits. 203 */ 204 if (isdigit((unsigned char)*p)) { 205 perm = (mode_t)strtol(p, NULL, 8); 206 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 207 free(saveset); 208 return (NULL); 209 } 210 while (*++p) 211 if (*p < '0' || *p > '7') { 212 free(saveset); 213 return (NULL); 214 } 215 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 216 return (saveset); 217 } 218 219 /* 220 * Build list of structures to set/clear/copy bits as described by 221 * each clause of the symbolic mode. 222 */ 223 for (;;) { 224 /* First, find out which bits might be modified. */ 225 for (who = 0;; ++p) { 226 switch (*p) { 227 case 'a': 228 who |= STANDARD_BITS; 229 break; 230 case 'u': 231 who |= S_ISUID|S_IRWXU; 232 break; 233 case 'g': 234 who |= S_ISGID|S_IRWXG; 235 break; 236 case 'o': 237 who |= S_IRWXO; 238 break; 239 default: 240 goto getop; 241 } 242 } 243 244 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 245 free(saveset); 246 return (NULL); 247 } 248 if (op == '=') 249 equalopdone = 0; 250 251 who &= ~S_ISTXT; 252 for (perm = 0, permXbits = 0;; ++p) { 253 switch (*p) { 254 case 'r': 255 perm |= S_IRUSR|S_IRGRP|S_IROTH; 256 break; 257 case 's': 258 /* If only "other" bits ignore set-id. */ 259 if (!who || who & ~S_IRWXO) 260 perm |= S_ISUID|S_ISGID; 261 break; 262 case 't': 263 /* If only "other" bits ignore sticky. */ 264 if (!who || who & ~S_IRWXO) { 265 who |= S_ISTXT; 266 perm |= S_ISTXT; 267 } 268 break; 269 case 'w': 270 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 271 break; 272 case 'X': 273 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 274 break; 275 case 'x': 276 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 277 break; 278 case 'u': 279 case 'g': 280 case 'o': 281 /* 282 * When ever we hit 'u', 'g', or 'o', we have 283 * to flush out any partial mode that we have, 284 * and then do the copying of the mode bits. 285 */ 286 if (perm) { 287 ADDCMD(op, who, perm, mask); 288 perm = 0; 289 } 290 if (op == '=') 291 equalopdone = 1; 292 if (op == '+' && permXbits) { 293 ADDCMD('X', who, permXbits, mask); 294 permXbits = 0; 295 } 296 ADDCMD(*p, who, op, mask); 297 break; 298 299 default: 300 /* 301 * Add any permissions that we haven't already 302 * done. 303 */ 304 if (perm || (op == '=' && !equalopdone)) { 305 if (op == '=') 306 equalopdone = 1; 307 ADDCMD(op, who, perm, mask); 308 perm = 0; 309 } 310 if (permXbits) { 311 ADDCMD('X', who, permXbits, mask); 312 permXbits = 0; 313 } 314 goto apply; 315 } 316 } 317 318 apply: if (!*p) 319 break; 320 if (*p != ',') 321 goto getop; 322 ++p; 323 } 324 set->cmd = 0; 325 #ifdef SETMODE_DEBUG 326 (void)printf("Before compress_mode()\n"); 327 dumpmode(saveset); 328 #endif 329 compress_mode(saveset); 330 #ifdef SETMODE_DEBUG 331 (void)printf("After compress_mode()\n"); 332 dumpmode(saveset); 333 #endif 334 return (saveset); 335 } 336 337 static BITCMD * 338 addcmd(set, op, who, oparg, mask) 339 BITCMD *set; 340 int oparg, who; 341 int op; 342 u_int mask; 343 { 344 switch (op) { 345 case '=': 346 set->cmd = '-'; 347 set->bits = who ? who : STANDARD_BITS; 348 set++; 349 350 op = '+'; 351 /* FALLTHROUGH */ 352 case '+': 353 case '-': 354 case 'X': 355 set->cmd = op; 356 set->bits = (who ? who : mask) & oparg; 357 break; 358 359 case 'u': 360 case 'g': 361 case 'o': 362 set->cmd = op; 363 if (who) { 364 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 365 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 366 ((who & S_IROTH) ? CMD2_OBITS : 0); 367 set->bits = ~0; 368 } else { 369 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 370 set->bits = mask; 371 } 372 373 if (oparg == '+') 374 set->cmd2 |= CMD2_SET; 375 else if (oparg == '-') 376 set->cmd2 |= CMD2_CLR; 377 else if (oparg == '=') 378 set->cmd2 |= CMD2_SET|CMD2_CLR; 379 break; 380 } 381 return (set + 1); 382 } 383 384 #ifdef SETMODE_DEBUG 385 static void 386 dumpmode(set) 387 BITCMD *set; 388 { 389 for (; set->cmd; ++set) 390 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 391 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 392 set->cmd2 & CMD2_CLR ? " CLR" : "", 393 set->cmd2 & CMD2_SET ? " SET" : "", 394 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 395 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 396 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 397 } 398 #endif 399 400 /* 401 * Given an array of bitcmd structures, compress by compacting consecutive 402 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 403 * 'g' and 'o' commands continue to be separate. They could probably be 404 * compacted, but it's not worth the effort. 405 */ 406 static void 407 compress_mode(set) 408 BITCMD *set; 409 { 410 BITCMD *nset; 411 int setbits, clrbits, Xbits, op; 412 413 for (nset = set;;) { 414 /* Copy over any 'u', 'g' and 'o' commands. */ 415 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 416 *set++ = *nset++; 417 if (!op) 418 return; 419 } 420 421 for (setbits = clrbits = Xbits = 0;; nset++) { 422 if ((op = nset->cmd) == '-') { 423 clrbits |= nset->bits; 424 setbits &= ~nset->bits; 425 Xbits &= ~nset->bits; 426 } else if (op == '+') { 427 setbits |= nset->bits; 428 clrbits &= ~nset->bits; 429 Xbits &= ~nset->bits; 430 } else if (op == 'X') 431 Xbits |= nset->bits & ~setbits; 432 else 433 break; 434 } 435 if (clrbits) { 436 set->cmd = '-'; 437 set->cmd2 = 0; 438 set->bits = clrbits; 439 set++; 440 } 441 if (setbits) { 442 set->cmd = '+'; 443 set->cmd2 = 0; 444 set->bits = setbits; 445 set++; 446 } 447 if (Xbits) { 448 set->cmd = 'X'; 449 set->cmd2 = 0; 450 set->bits = Xbits; 451 set++; 452 } 453 } 454 } 455