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 1.7 2005/11/19 22:32:53 swildner 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 #include <unistd.h> 50 51 #ifdef SETMODE_DEBUG 52 #include <stdio.h> 53 #endif 54 #include "un-namespace.h" 55 56 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 57 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 58 59 typedef struct bitcmd { 60 char cmd; 61 char cmd2; 62 mode_t bits; 63 } BITCMD; 64 65 #define CMD2_CLR 0x01 66 #define CMD2_SET 0x02 67 #define CMD2_GBITS 0x04 68 #define CMD2_OBITS 0x08 69 #define CMD2_UBITS 0x10 70 71 static BITCMD *addcmd (BITCMD *, int, int, int, u_int); 72 static void compress_mode (BITCMD *); 73 #ifdef SETMODE_DEBUG 74 static void dumpmode (BITCMD *); 75 #endif 76 77 /* 78 * Given the old mode and an array of bitcmd structures, apply the operations 79 * described in the bitcmd structures to the old mode, and return the new mode. 80 * Note that there is no '=' command; a strict assignment is just a '-' (clear 81 * bits) followed by a '+' (set bits). 82 */ 83 mode_t 84 getmode(const void *bbox, mode_t omode) 85 { 86 BITCMD *set; 87 mode_t clrval, newmode, value; 88 89 set = (BITCMD *)bbox; 90 newmode = omode; 91 for (value = 0;; set++) 92 switch(set->cmd) { 93 /* 94 * When copying the user, group or other bits around, we "know" 95 * where the bits are in the mode so that we can do shifts to 96 * copy them around. If we don't use shifts, it gets real 97 * grundgy with lots of single bit checks and bit sets. 98 */ 99 case 'u': 100 value = (newmode & S_IRWXU) >> 6; 101 goto common; 102 103 case 'g': 104 value = (newmode & S_IRWXG) >> 3; 105 goto common; 106 107 case 'o': 108 value = newmode & S_IRWXO; 109 common: if (set->cmd2 & CMD2_CLR) { 110 clrval = 111 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 112 if (set->cmd2 & CMD2_UBITS) 113 newmode &= ~((clrval<<6) & set->bits); 114 if (set->cmd2 & CMD2_GBITS) 115 newmode &= ~((clrval<<3) & set->bits); 116 if (set->cmd2 & CMD2_OBITS) 117 newmode &= ~(clrval & set->bits); 118 } 119 if (set->cmd2 & CMD2_SET) { 120 if (set->cmd2 & CMD2_UBITS) 121 newmode |= (value<<6) & set->bits; 122 if (set->cmd2 & CMD2_GBITS) 123 newmode |= (value<<3) & set->bits; 124 if (set->cmd2 & CMD2_OBITS) 125 newmode |= value & set->bits; 126 } 127 break; 128 129 case '+': 130 newmode |= set->bits; 131 break; 132 133 case '-': 134 newmode &= ~set->bits; 135 break; 136 137 case 'X': 138 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 139 newmode |= set->bits; 140 break; 141 142 case '\0': 143 default: 144 #ifdef SETMODE_DEBUG 145 printf("getmode:%04o -> %04o\n", omode, newmode); 146 #endif 147 return (newmode); 148 } 149 } 150 151 #define ADDCMD(a, b, c, d) \ 152 if (set >= endset) { \ 153 BITCMD *newset; \ 154 setlen += SET_LEN_INCR; \ 155 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 156 if (!saveset) \ 157 return (NULL); \ 158 set = newset + (set - saveset); \ 159 saveset = newset; \ 160 endset = newset + (setlen - 2); \ 161 } \ 162 set = addcmd(set, (a), (b), (c), (d)) 163 164 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 165 166 void * 167 setmode(const char *p) 168 { 169 int perm, who; 170 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 _sigprocmask(SIG_BLOCK, &sigset, &sigoset); 187 umask(mask = umask(0)); 188 mask = ~mask; 189 _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 printf("Before compress_mode()\n"); 325 dumpmode(saveset); 326 #endif 327 compress_mode(saveset); 328 #ifdef SETMODE_DEBUG 329 printf("After compress_mode()\n"); 330 dumpmode(saveset); 331 #endif 332 return (saveset); 333 } 334 335 static BITCMD * 336 addcmd(BITCMD *set, int op, int who, int oparg, u_int mask) 337 { 338 switch (op) { 339 case '=': 340 set->cmd = '-'; 341 set->bits = who ? who : STANDARD_BITS; 342 set++; 343 344 op = '+'; 345 /* FALLTHROUGH */ 346 case '+': 347 case '-': 348 case 'X': 349 set->cmd = op; 350 set->bits = (who ? who : mask) & oparg; 351 break; 352 353 case 'u': 354 case 'g': 355 case 'o': 356 set->cmd = op; 357 if (who) { 358 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 359 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 360 ((who & S_IROTH) ? CMD2_OBITS : 0); 361 set->bits = ~0; 362 } else { 363 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 364 set->bits = mask; 365 } 366 367 if (oparg == '+') 368 set->cmd2 |= CMD2_SET; 369 else if (oparg == '-') 370 set->cmd2 |= CMD2_CLR; 371 else if (oparg == '=') 372 set->cmd2 |= CMD2_SET|CMD2_CLR; 373 break; 374 } 375 return (set + 1); 376 } 377 378 #ifdef SETMODE_DEBUG 379 static void 380 dumpmode(BITCMD *set) 381 { 382 for (; set->cmd; ++set) 383 printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 384 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 385 set->cmd2 & CMD2_CLR ? " CLR" : "", 386 set->cmd2 & CMD2_SET ? " SET" : "", 387 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 388 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 389 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 390 } 391 #endif 392 393 /* 394 * Given an array of bitcmd structures, compress by compacting consecutive 395 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 396 * 'g' and 'o' commands continue to be separate. They could probably be 397 * compacted, but it's not worth the effort. 398 */ 399 static void 400 compress_mode(BITCMD *set) 401 { 402 BITCMD *nset; 403 int setbits, clrbits, Xbits, op; 404 405 for (nset = set;;) { 406 /* Copy over any 'u', 'g' and 'o' commands. */ 407 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 408 *set++ = *nset++; 409 if (!op) 410 return; 411 } 412 413 for (setbits = clrbits = Xbits = 0;; nset++) { 414 if ((op = nset->cmd) == '-') { 415 clrbits |= nset->bits; 416 setbits &= ~nset->bits; 417 Xbits &= ~nset->bits; 418 } else if (op == '+') { 419 setbits |= nset->bits; 420 clrbits &= ~nset->bits; 421 Xbits &= ~nset->bits; 422 } else if (op == 'X') 423 Xbits |= nset->bits & ~setbits; 424 else 425 break; 426 } 427 if (clrbits) { 428 set->cmd = '-'; 429 set->cmd2 = 0; 430 set->bits = clrbits; 431 set++; 432 } 433 if (setbits) { 434 set->cmd = '+'; 435 set->cmd2 = 0; 436 set->bits = setbits; 437 set++; 438 } 439 if (Xbits) { 440 set->cmd = 'X'; 441 set->cmd2 = 0; 442 set->bits = Xbits; 443 set++; 444 } 445 } 446 } 447