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