1 /* $NetBSD: setmode.c,v 1.11 1995/03/04 01:55:58 cgd Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Dave Borman at Cray Research, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 #if 0 41 static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94"; 42 #else 43 static char rcsid[] = "$NetBSD: setmode.c,v 1.11 1995/03/04 01:55:58 cgd Exp $"; 44 #endif 45 #endif /* LIBC_SCCS and not lint */ 46 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 50 #include <ctype.h> 51 #include <errno.h> 52 #include <signal.h> 53 #include <stddef.h> 54 #include <stdlib.h> 55 56 #ifdef SETMODE_DEBUG 57 #include <stdio.h> 58 #endif 59 60 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 61 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 62 63 typedef struct bitcmd { 64 char cmd; 65 char cmd2; 66 mode_t bits; 67 } BITCMD; 68 69 #define CMD2_CLR 0x01 70 #define CMD2_SET 0x02 71 #define CMD2_GBITS 0x04 72 #define CMD2_OBITS 0x08 73 #define CMD2_UBITS 0x10 74 75 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 76 static int compress_mode __P((BITCMD *)); 77 #ifdef SETMODE_DEBUG 78 static void dumpmode __P((BITCMD *)); 79 #endif 80 81 /* 82 * Given the old mode and an array of bitcmd structures, apply the operations 83 * described in the bitcmd structures to the old mode, and return the new mode. 84 * Note that there is no '=' command; a strict assignment is just a '-' (clear 85 * bits) followed by a '+' (set bits). 86 */ 87 mode_t 88 getmode(bbox, omode) 89 void *bbox; 90 mode_t omode; 91 { 92 register BITCMD *set; 93 register mode_t clrval, newmode, value; 94 95 set = (BITCMD *)bbox; 96 newmode = omode; 97 for (value = 0;; set++) 98 switch(set->cmd) { 99 /* 100 * When copying the user, group or other bits around, we "know" 101 * where the bits are in the mode so that we can do shifts to 102 * copy them around. If we don't use shifts, it gets real 103 * grundgy with lots of single bit checks and bit sets. 104 */ 105 case 'u': 106 value = (newmode & S_IRWXU) >> 6; 107 goto common; 108 109 case 'g': 110 value = (newmode & S_IRWXG) >> 3; 111 goto common; 112 113 case 'o': 114 value = newmode & S_IRWXO; 115 common: if (set->cmd2 & CMD2_CLR) { 116 clrval = 117 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 118 if (set->cmd2 & CMD2_UBITS) 119 newmode &= ~((clrval<<6) & set->bits); 120 if (set->cmd2 & CMD2_GBITS) 121 newmode &= ~((clrval<<3) & set->bits); 122 if (set->cmd2 & CMD2_OBITS) 123 newmode &= ~(clrval & set->bits); 124 } 125 if (set->cmd2 & CMD2_SET) { 126 if (set->cmd2 & CMD2_UBITS) 127 newmode |= (value<<6) & set->bits; 128 if (set->cmd2 & CMD2_GBITS) 129 newmode |= (value<<3) & set->bits; 130 if (set->cmd2 & CMD2_OBITS) 131 newmode |= value & set->bits; 132 } 133 break; 134 135 case '+': 136 newmode |= set->bits; 137 break; 138 139 case '-': 140 newmode &= ~set->bits; 141 break; 142 143 case 'X': 144 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 145 newmode |= set->bits; 146 break; 147 148 case '\0': 149 default: 150 #ifdef SETMODE_DEBUG 151 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 152 #endif 153 return (newmode); 154 } 155 } 156 157 #define ADDCMD(a, b, c, d) \ 158 if (set >= endset) { \ 159 register BITCMD *newset; \ 160 setlen += SET_LEN_INCR; \ 161 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 162 if (!saveset) \ 163 return (NULL); \ 164 set = newset + (set - saveset); \ 165 saveset = newset; \ 166 endset = newset + (setlen - 2); \ 167 } \ 168 set = addcmd(set, (a), (b), (c), (d)) 169 170 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 171 172 void * 173 setmode(p) 174 register char *p; 175 { 176 register int perm, who; 177 register char op; 178 BITCMD *set, *saveset, *endset; 179 sigset_t sigset, sigoset; 180 mode_t mask; 181 int equalopdone, permXbits, setlen; 182 183 if (!*p) 184 return (NULL); 185 186 /* 187 * Get a copy of the mask for the permissions that are mask relative. 188 * Flip the bits, we want what's not set. Since it's possible that 189 * the caller is opening files inside a signal handler, protect them 190 * as best we can. 191 */ 192 sigfillset(&sigset); 193 (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset); 194 (void)umask(mask = umask(0)); 195 mask = ~mask; 196 (void)sigprocmask(SIG_SETMASK, &sigoset, NULL); 197 198 setlen = SET_LEN + 2; 199 200 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 201 return (NULL); 202 saveset = set; 203 endset = set + (setlen - 2); 204 205 /* 206 * If an absolute number, get it and return; disallow non-octal digits 207 * or illegal bits. 208 */ 209 if (isdigit(*p)) { 210 perm = (mode_t)strtol(p, NULL, 8); 211 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 212 free(saveset); 213 return (NULL); 214 } 215 while (*++p) 216 if (*p < '0' || *p > '7') { 217 free(saveset); 218 return (NULL); 219 } 220 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 221 return (saveset); 222 } 223 224 /* 225 * Build list of structures to set/clear/copy bits as described by 226 * each clause of the symbolic mode. 227 */ 228 for (;;) { 229 /* First, find out which bits might be modified. */ 230 for (who = 0;; ++p) { 231 switch (*p) { 232 case 'a': 233 who |= STANDARD_BITS; 234 break; 235 case 'u': 236 who |= S_ISUID|S_IRWXU; 237 break; 238 case 'g': 239 who |= S_ISGID|S_IRWXG; 240 break; 241 case 'o': 242 who |= S_IRWXO; 243 break; 244 default: 245 goto getop; 246 } 247 } 248 249 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 250 free(saveset); 251 return (NULL); 252 } 253 if (op == '=') 254 equalopdone = 0; 255 256 who &= ~S_ISTXT; 257 for (perm = 0, permXbits = 0;; ++p) { 258 switch (*p) { 259 case 'r': 260 perm |= S_IRUSR|S_IRGRP|S_IROTH; 261 break; 262 case 's': 263 /* If only "other" bits ignore set-id. */ 264 if (who & ~S_IRWXO) 265 perm |= S_ISUID|S_ISGID; 266 break; 267 case 't': 268 /* If only "other" bits ignore sticky. */ 269 if (who & ~S_IRWXO) { 270 who |= S_ISTXT; 271 perm |= S_ISTXT; 272 } 273 break; 274 case 'w': 275 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 276 break; 277 case 'X': 278 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 279 break; 280 case 'x': 281 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 282 break; 283 case 'u': 284 case 'g': 285 case 'o': 286 /* 287 * When ever we hit 'u', 'g', or 'o', we have 288 * to flush out any partial mode that we have, 289 * and then do the copying of the mode bits. 290 */ 291 if (perm) { 292 ADDCMD(op, who, perm, mask); 293 perm = 0; 294 } 295 if (op == '=') 296 equalopdone = 1; 297 if (op == '+' && permXbits) { 298 ADDCMD('X', who, permXbits, mask); 299 permXbits = 0; 300 } 301 ADDCMD(*p, who, op, mask); 302 break; 303 304 default: 305 /* 306 * Add any permissions that we haven't already 307 * done. 308 */ 309 if (perm || (op == '=' && !equalopdone)) { 310 if (op == '=') 311 equalopdone = 1; 312 ADDCMD(op, who, perm, mask); 313 perm = 0; 314 } 315 if (permXbits) { 316 ADDCMD('X', who, permXbits, mask); 317 permXbits = 0; 318 } 319 goto apply; 320 } 321 } 322 323 apply: if (!*p) 324 break; 325 if (*p != ',') 326 goto getop; 327 ++p; 328 } 329 set->cmd = 0; 330 #ifdef SETMODE_DEBUG 331 (void)printf("Before compress_mode()\n"); 332 dumpmode(saveset); 333 #endif 334 compress_mode(saveset); 335 #ifdef SETMODE_DEBUG 336 (void)printf("After compress_mode()\n"); 337 dumpmode(saveset); 338 #endif 339 return (saveset); 340 } 341 342 static BITCMD * 343 addcmd(set, op, who, oparg, mask) 344 BITCMD *set; 345 register int oparg, who; 346 register int op; 347 u_int mask; 348 { 349 switch (op) { 350 case '=': 351 set->cmd = '-'; 352 set->bits = who ? who : STANDARD_BITS; 353 set++; 354 355 op = '+'; 356 /* FALLTHROUGH */ 357 case '+': 358 case '-': 359 case 'X': 360 set->cmd = op; 361 set->bits = (who ? who : mask) & oparg; 362 break; 363 364 case 'u': 365 case 'g': 366 case 'o': 367 set->cmd = op; 368 if (who) { 369 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 370 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 371 ((who & S_IROTH) ? CMD2_OBITS : 0); 372 set->bits = ~0; 373 } else { 374 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 375 set->bits = mask; 376 } 377 378 if (oparg == '+') 379 set->cmd2 |= CMD2_SET; 380 else if (oparg == '-') 381 set->cmd2 |= CMD2_CLR; 382 else if (oparg == '=') 383 set->cmd2 |= CMD2_SET|CMD2_CLR; 384 break; 385 } 386 return (set + 1); 387 } 388 389 #ifdef SETMODE_DEBUG 390 static void 391 dumpmode(set) 392 register BITCMD *set; 393 { 394 for (; set->cmd; ++set) 395 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 396 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 397 set->cmd2 & CMD2_CLR ? " CLR" : "", 398 set->cmd2 & CMD2_SET ? " SET" : "", 399 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 400 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 401 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 402 } 403 #endif 404 405 /* 406 * Given an array of bitcmd structures, compress by compacting consecutive 407 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 408 * 'g' and 'o' commands continue to be separate. They could probably be 409 * compacted, but it's not worth the effort. 410 */ 411 static int 412 compress_mode(set) 413 register BITCMD *set; 414 { 415 register BITCMD *nset; 416 register int setbits, clrbits, Xbits, op; 417 418 for (nset = set;;) { 419 /* Copy over any 'u', 'g' and 'o' commands. */ 420 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 421 *set++ = *nset++; 422 if (!op) 423 return; 424 } 425 426 for (setbits = clrbits = Xbits = 0;; nset++) { 427 if ((op = nset->cmd) == '-') { 428 clrbits |= nset->bits; 429 setbits &= ~nset->bits; 430 Xbits &= ~nset->bits; 431 } else if (op == '+') { 432 setbits |= nset->bits; 433 clrbits &= ~nset->bits; 434 Xbits &= ~nset->bits; 435 } else if (op == 'X') 436 Xbits |= nset->bits & ~setbits; 437 else 438 break; 439 } 440 if (clrbits) { 441 set->cmd = '-'; 442 set->cmd2 = 0; 443 set->bits = clrbits; 444 set++; 445 } 446 if (setbits) { 447 set->cmd = '+'; 448 set->cmd2 = 0; 449 set->bits = setbits; 450 set++; 451 } 452 if (Xbits) { 453 set->cmd = 'X'; 454 set->cmd2 = 0; 455 set->bits = Xbits; 456 set++; 457 } 458 } 459 } 460