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 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 48 #include <ctype.h> 49 #include <errno.h> 50 #include <signal.h> 51 #include <stddef.h> 52 #include <stdlib.h> 53 54 #ifdef SETMODE_DEBUG 55 #include <stdio.h> 56 #endif 57 58 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 59 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 60 61 typedef struct bitcmd { 62 char cmd; 63 char cmd2; 64 mode_t bits; 65 } BITCMD; 66 67 #define CMD2_CLR 0x01 68 #define CMD2_SET 0x02 69 #define CMD2_GBITS 0x04 70 #define CMD2_OBITS 0x08 71 #define CMD2_UBITS 0x10 72 73 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 74 static void compress_mode __P((BITCMD *)); 75 #ifdef SETMODE_DEBUG 76 static void dumpmode __P((BITCMD *)); 77 #endif 78 79 /* 80 * Given the old mode and an array of bitcmd structures, apply the operations 81 * described in the bitcmd structures to the old mode, and return the new mode. 82 * Note that there is no '=' command; a strict assignment is just a '-' (clear 83 * bits) followed by a '+' (set bits). 84 */ 85 mode_t 86 getmode(bbox, omode) 87 void *bbox; 88 mode_t omode; 89 { 90 register BITCMD *set; 91 register mode_t clrval, newmode, value; 92 93 set = (BITCMD *)bbox; 94 newmode = omode; 95 for (value = 0;; set++) 96 switch(set->cmd) { 97 /* 98 * When copying the user, group or other bits around, we "know" 99 * where the bits are in the mode so that we can do shifts to 100 * copy them around. If we don't use shifts, it gets real 101 * grundgy with lots of single bit checks and bit sets. 102 */ 103 case 'u': 104 value = (newmode & S_IRWXU) >> 6; 105 goto common; 106 107 case 'g': 108 value = (newmode & S_IRWXG) >> 3; 109 goto common; 110 111 case 'o': 112 value = newmode & S_IRWXO; 113 common: if (set->cmd2 & CMD2_CLR) { 114 clrval = 115 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 116 if (set->cmd2 & CMD2_UBITS) 117 newmode &= ~((clrval<<6) & set->bits); 118 if (set->cmd2 & CMD2_GBITS) 119 newmode &= ~((clrval<<3) & set->bits); 120 if (set->cmd2 & CMD2_OBITS) 121 newmode &= ~(clrval & set->bits); 122 } 123 if (set->cmd2 & CMD2_SET) { 124 if (set->cmd2 & CMD2_UBITS) 125 newmode |= (value<<6) & set->bits; 126 if (set->cmd2 & CMD2_GBITS) 127 newmode |= (value<<3) & set->bits; 128 if (set->cmd2 & CMD2_OBITS) 129 newmode |= value & set->bits; 130 } 131 break; 132 133 case '+': 134 newmode |= set->bits; 135 break; 136 137 case '-': 138 newmode &= ~set->bits; 139 break; 140 141 case 'X': 142 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 143 newmode |= set->bits; 144 break; 145 146 case '\0': 147 default: 148 #ifdef SETMODE_DEBUG 149 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 150 #endif 151 return (newmode); 152 } 153 } 154 155 #define ADDCMD(a, b, c, d) \ 156 if (set >= endset) { \ 157 register BITCMD *newset; \ 158 setlen += SET_LEN_INCR; \ 159 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 160 if (!saveset) \ 161 return (NULL); \ 162 set = newset + (set - saveset); \ 163 saveset = newset; \ 164 endset = newset + (setlen - 2); \ 165 } \ 166 set = addcmd(set, (a), (b), (c), (d)) 167 168 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 169 170 void * 171 setmode(p) 172 register char *p; 173 { 174 register int perm, who; 175 register char op; 176 BITCMD *set, *saveset, *endset; 177 sigset_t sigset, sigoset; 178 mode_t mask; 179 int equalopdone=0, permXbits, setlen; 180 181 if (!*p) 182 return (NULL); 183 184 /* 185 * Get a copy of the mask for the permissions that are mask relative. 186 * Flip the bits, we want what's not set. Since it's possible that 187 * the caller is opening files inside a signal handler, protect them 188 * as best we can. 189 */ 190 sigfillset(&sigset); 191 (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset); 192 (void)umask(mask = umask(0)); 193 mask = ~mask; 194 (void)sigprocmask(SIG_SETMASK, &sigoset, NULL); 195 196 setlen = SET_LEN + 2; 197 198 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 199 return (NULL); 200 saveset = set; 201 endset = set + (setlen - 2); 202 203 /* 204 * If an absolute number, get it and return; disallow non-octal digits 205 * or illegal bits. 206 */ 207 if (isdigit((unsigned char)*p)) { 208 perm = (mode_t)strtol(p, NULL, 8); 209 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 210 free(saveset); 211 return (NULL); 212 } 213 while (*++p) 214 if (*p < '0' || *p > '7') { 215 free(saveset); 216 return (NULL); 217 } 218 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 219 return (saveset); 220 } 221 222 /* 223 * Build list of structures to set/clear/copy bits as described by 224 * each clause of the symbolic mode. 225 */ 226 for (;;) { 227 /* First, find out which bits might be modified. */ 228 for (who = 0;; ++p) { 229 switch (*p) { 230 case 'a': 231 who |= STANDARD_BITS; 232 break; 233 case 'u': 234 who |= S_ISUID|S_IRWXU; 235 break; 236 case 'g': 237 who |= S_ISGID|S_IRWXG; 238 break; 239 case 'o': 240 who |= S_IRWXO; 241 break; 242 default: 243 goto getop; 244 } 245 } 246 247 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 248 free(saveset); 249 return (NULL); 250 } 251 if (op == '=') 252 equalopdone = 0; 253 254 who &= ~S_ISTXT; 255 for (perm = 0, permXbits = 0;; ++p) { 256 switch (*p) { 257 case 'r': 258 perm |= S_IRUSR|S_IRGRP|S_IROTH; 259 break; 260 case 's': 261 /* If only "other" bits ignore set-id. */ 262 if (!who || who & ~S_IRWXO) 263 perm |= S_ISUID|S_ISGID; 264 break; 265 case 't': 266 /* If only "other" bits ignore sticky. */ 267 if (!who || who & ~S_IRWXO) { 268 who |= S_ISTXT; 269 perm |= S_ISTXT; 270 } 271 break; 272 case 'w': 273 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 274 break; 275 case 'X': 276 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 277 break; 278 case 'x': 279 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 280 break; 281 case 'u': 282 case 'g': 283 case 'o': 284 /* 285 * When ever we hit 'u', 'g', or 'o', we have 286 * to flush out any partial mode that we have, 287 * and then do the copying of the mode bits. 288 */ 289 if (perm) { 290 ADDCMD(op, who, perm, mask); 291 perm = 0; 292 } 293 if (op == '=') 294 equalopdone = 1; 295 if (op == '+' && permXbits) { 296 ADDCMD('X', who, permXbits, mask); 297 permXbits = 0; 298 } 299 ADDCMD(*p, who, op, mask); 300 break; 301 302 default: 303 /* 304 * Add any permissions that we haven't already 305 * done. 306 */ 307 if (perm || (op == '=' && !equalopdone)) { 308 if (op == '=') 309 equalopdone = 1; 310 ADDCMD(op, who, perm, mask); 311 perm = 0; 312 } 313 if (permXbits) { 314 ADDCMD('X', who, permXbits, mask); 315 permXbits = 0; 316 } 317 goto apply; 318 } 319 } 320 321 apply: if (!*p) 322 break; 323 if (*p != ',') 324 goto getop; 325 ++p; 326 } 327 set->cmd = 0; 328 #ifdef SETMODE_DEBUG 329 (void)printf("Before compress_mode()\n"); 330 dumpmode(saveset); 331 #endif 332 compress_mode(saveset); 333 #ifdef SETMODE_DEBUG 334 (void)printf("After compress_mode()\n"); 335 dumpmode(saveset); 336 #endif 337 return (saveset); 338 } 339 340 static BITCMD * 341 addcmd(set, op, who, oparg, mask) 342 BITCMD *set; 343 register int oparg, who; 344 register int op; 345 u_int mask; 346 { 347 switch (op) { 348 case '=': 349 set->cmd = '-'; 350 set->bits = who ? who : STANDARD_BITS; 351 set++; 352 353 op = '+'; 354 /* FALLTHROUGH */ 355 case '+': 356 case '-': 357 case 'X': 358 set->cmd = op; 359 set->bits = (who ? who : mask) & oparg; 360 break; 361 362 case 'u': 363 case 'g': 364 case 'o': 365 set->cmd = op; 366 if (who) { 367 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 368 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 369 ((who & S_IROTH) ? CMD2_OBITS : 0); 370 set->bits = ~0; 371 } else { 372 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 373 set->bits = mask; 374 } 375 376 if (oparg == '+') 377 set->cmd2 |= CMD2_SET; 378 else if (oparg == '-') 379 set->cmd2 |= CMD2_CLR; 380 else if (oparg == '=') 381 set->cmd2 |= CMD2_SET|CMD2_CLR; 382 break; 383 } 384 return (set + 1); 385 } 386 387 #ifdef SETMODE_DEBUG 388 static void 389 dumpmode(set) 390 register BITCMD *set; 391 { 392 for (; set->cmd; ++set) 393 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 394 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 395 set->cmd2 & CMD2_CLR ? " CLR" : "", 396 set->cmd2 & CMD2_SET ? " SET" : "", 397 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 398 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 399 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 400 } 401 #endif 402 403 /* 404 * Given an array of bitcmd structures, compress by compacting consecutive 405 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 406 * 'g' and 'o' commands continue to be separate. They could probably be 407 * compacted, but it's not worth the effort. 408 */ 409 static void 410 compress_mode(set) 411 register BITCMD *set; 412 { 413 register BITCMD *nset; 414 register int setbits, clrbits, Xbits, op; 415 416 for (nset = set;;) { 417 /* Copy over any 'u', 'g' and 'o' commands. */ 418 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 419 *set++ = *nset++; 420 if (!op) 421 return; 422 } 423 424 for (setbits = clrbits = Xbits = 0;; nset++) { 425 if ((op = nset->cmd) == '-') { 426 clrbits |= nset->bits; 427 setbits &= ~nset->bits; 428 Xbits &= ~nset->bits; 429 } else if (op == '+') { 430 setbits |= nset->bits; 431 clrbits &= ~nset->bits; 432 Xbits &= ~nset->bits; 433 } else if (op == 'X') 434 Xbits |= nset->bits & ~setbits; 435 else 436 break; 437 } 438 if (clrbits) { 439 set->cmd = '-'; 440 set->cmd2 = 0; 441 set->bits = clrbits; 442 set++; 443 } 444 if (setbits) { 445 set->cmd = '+'; 446 set->cmd2 = 0; 447 set->bits = setbits; 448 set++; 449 } 450 if (Xbits) { 451 set->cmd = 'X'; 452 set->cmd2 = 0; 453 set->bits = Xbits; 454 set++; 455 } 456 } 457 } 458