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