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 "namespace.h" 46 #include <sys/types.h> 47 #include <sys/stat.h> 48 49 #include <ctype.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 #include "un-namespace.h" 58 59 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 60 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 61 62 typedef struct bitcmd { 63 char cmd; 64 char cmd2; 65 mode_t bits; 66 } BITCMD; 67 68 #define CMD2_CLR 0x01 69 #define CMD2_SET 0x02 70 #define CMD2_GBITS 0x04 71 #define CMD2_OBITS 0x08 72 #define CMD2_UBITS 0x10 73 74 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 75 static void compress_mode __P((BITCMD *)); 76 #ifdef SETMODE_DEBUG 77 static void dumpmode __P((BITCMD *)); 78 #endif 79 80 /* 81 * Given the old mode and an array of bitcmd structures, apply the operations 82 * described in the bitcmd structures to the old mode, and return the new mode. 83 * Note that there is no '=' command; a strict assignment is just a '-' (clear 84 * bits) followed by a '+' (set bits). 85 */ 86 mode_t 87 getmode(bbox, omode) 88 void *bbox; 89 mode_t omode; 90 { 91 register BITCMD *set; 92 register mode_t clrval, newmode, value; 93 94 set = (BITCMD *)bbox; 95 newmode = omode; 96 for (value = 0;; set++) 97 switch(set->cmd) { 98 /* 99 * When copying the user, group or other bits around, we "know" 100 * where the bits are in the mode so that we can do shifts to 101 * copy them around. If we don't use shifts, it gets real 102 * grundgy with lots of single bit checks and bit sets. 103 */ 104 case 'u': 105 value = (newmode & S_IRWXU) >> 6; 106 goto common; 107 108 case 'g': 109 value = (newmode & S_IRWXG) >> 3; 110 goto common; 111 112 case 'o': 113 value = newmode & S_IRWXO; 114 common: if (set->cmd2 & CMD2_CLR) { 115 clrval = 116 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 117 if (set->cmd2 & CMD2_UBITS) 118 newmode &= ~((clrval<<6) & set->bits); 119 if (set->cmd2 & CMD2_GBITS) 120 newmode &= ~((clrval<<3) & set->bits); 121 if (set->cmd2 & CMD2_OBITS) 122 newmode &= ~(clrval & set->bits); 123 } 124 if (set->cmd2 & CMD2_SET) { 125 if (set->cmd2 & CMD2_UBITS) 126 newmode |= (value<<6) & set->bits; 127 if (set->cmd2 & CMD2_GBITS) 128 newmode |= (value<<3) & set->bits; 129 if (set->cmd2 & CMD2_OBITS) 130 newmode |= value & set->bits; 131 } 132 break; 133 134 case '+': 135 newmode |= set->bits; 136 break; 137 138 case '-': 139 newmode &= ~set->bits; 140 break; 141 142 case 'X': 143 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 144 newmode |= set->bits; 145 break; 146 147 case '\0': 148 default: 149 #ifdef SETMODE_DEBUG 150 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 151 #endif 152 return (newmode); 153 } 154 } 155 156 #define ADDCMD(a, b, c, d) \ 157 if (set >= endset) { \ 158 register BITCMD *newset; \ 159 setlen += SET_LEN_INCR; \ 160 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 161 if (!saveset) \ 162 return (NULL); \ 163 set = newset + (set - saveset); \ 164 saveset = newset; \ 165 endset = newset + (setlen - 2); \ 166 } \ 167 set = addcmd(set, (a), (b), (c), (d)) 168 169 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 170 171 void * 172 setmode(p) 173 register char *p; 174 { 175 register int perm, who; 176 register char op; 177 BITCMD *set, *saveset, *endset; 178 sigset_t sigset, sigoset; 179 mode_t mask; 180 int equalopdone=0, permXbits, setlen; 181 182 if (!*p) 183 return (NULL); 184 185 /* 186 * Get a copy of the mask for the permissions that are mask relative. 187 * Flip the bits, we want what's not set. Since it's possible that 188 * the caller is opening files inside a signal handler, protect them 189 * as best we can. 190 */ 191 sigfillset(&sigset); 192 (void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset); 193 (void)umask(mask = umask(0)); 194 mask = ~mask; 195 (void)_sigprocmask(SIG_SETMASK, &sigoset, NULL); 196 197 setlen = SET_LEN + 2; 198 199 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 200 return (NULL); 201 saveset = set; 202 endset = set + (setlen - 2); 203 204 /* 205 * If an absolute number, get it and return; disallow non-octal digits 206 * or illegal bits. 207 */ 208 if (isdigit((unsigned char)*p)) { 209 perm = (mode_t)strtol(p, NULL, 8); 210 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 211 free(saveset); 212 return (NULL); 213 } 214 while (*++p) 215 if (*p < '0' || *p > '7') { 216 free(saveset); 217 return (NULL); 218 } 219 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 220 return (saveset); 221 } 222 223 /* 224 * Build list of structures to set/clear/copy bits as described by 225 * each clause of the symbolic mode. 226 */ 227 for (;;) { 228 /* First, find out which bits might be modified. */ 229 for (who = 0;; ++p) { 230 switch (*p) { 231 case 'a': 232 who |= STANDARD_BITS; 233 break; 234 case 'u': 235 who |= S_ISUID|S_IRWXU; 236 break; 237 case 'g': 238 who |= S_ISGID|S_IRWXG; 239 break; 240 case 'o': 241 who |= S_IRWXO; 242 break; 243 default: 244 goto getop; 245 } 246 } 247 248 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 249 free(saveset); 250 return (NULL); 251 } 252 if (op == '=') 253 equalopdone = 0; 254 255 who &= ~S_ISTXT; 256 for (perm = 0, permXbits = 0;; ++p) { 257 switch (*p) { 258 case 'r': 259 perm |= S_IRUSR|S_IRGRP|S_IROTH; 260 break; 261 case 's': 262 /* If only "other" bits ignore set-id. */ 263 if (!who || who & ~S_IRWXO) 264 perm |= S_ISUID|S_ISGID; 265 break; 266 case 't': 267 /* If only "other" bits ignore sticky. */ 268 if (!who || who & ~S_IRWXO) { 269 who |= S_ISTXT; 270 perm |= S_ISTXT; 271 } 272 break; 273 case 'w': 274 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 275 break; 276 case 'X': 277 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 278 break; 279 case 'x': 280 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 281 break; 282 case 'u': 283 case 'g': 284 case 'o': 285 /* 286 * When ever we hit 'u', 'g', or 'o', we have 287 * to flush out any partial mode that we have, 288 * and then do the copying of the mode bits. 289 */ 290 if (perm) { 291 ADDCMD(op, who, perm, mask); 292 perm = 0; 293 } 294 if (op == '=') 295 equalopdone = 1; 296 if (op == '+' && permXbits) { 297 ADDCMD('X', who, permXbits, mask); 298 permXbits = 0; 299 } 300 ADDCMD(*p, who, op, mask); 301 break; 302 303 default: 304 /* 305 * Add any permissions that we haven't already 306 * done. 307 */ 308 if (perm || (op == '=' && !equalopdone)) { 309 if (op == '=') 310 equalopdone = 1; 311 ADDCMD(op, who, perm, mask); 312 perm = 0; 313 } 314 if (permXbits) { 315 ADDCMD('X', who, permXbits, mask); 316 permXbits = 0; 317 } 318 goto apply; 319 } 320 } 321 322 apply: if (!*p) 323 break; 324 if (*p != ',') 325 goto getop; 326 ++p; 327 } 328 set->cmd = 0; 329 #ifdef SETMODE_DEBUG 330 (void)printf("Before compress_mode()\n"); 331 dumpmode(saveset); 332 #endif 333 compress_mode(saveset); 334 #ifdef SETMODE_DEBUG 335 (void)printf("After compress_mode()\n"); 336 dumpmode(saveset); 337 #endif 338 return (saveset); 339 } 340 341 static BITCMD * 342 addcmd(set, op, who, oparg, mask) 343 BITCMD *set; 344 register int oparg, who; 345 register int op; 346 u_int mask; 347 { 348 switch (op) { 349 case '=': 350 set->cmd = '-'; 351 set->bits = who ? who : STANDARD_BITS; 352 set++; 353 354 op = '+'; 355 /* FALLTHROUGH */ 356 case '+': 357 case '-': 358 case 'X': 359 set->cmd = op; 360 set->bits = (who ? who : mask) & oparg; 361 break; 362 363 case 'u': 364 case 'g': 365 case 'o': 366 set->cmd = op; 367 if (who) { 368 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 369 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 370 ((who & S_IROTH) ? CMD2_OBITS : 0); 371 set->bits = ~0; 372 } else { 373 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 374 set->bits = mask; 375 } 376 377 if (oparg == '+') 378 set->cmd2 |= CMD2_SET; 379 else if (oparg == '-') 380 set->cmd2 |= CMD2_CLR; 381 else if (oparg == '=') 382 set->cmd2 |= CMD2_SET|CMD2_CLR; 383 break; 384 } 385 return (set + 1); 386 } 387 388 #ifdef SETMODE_DEBUG 389 static void 390 dumpmode(set) 391 register BITCMD *set; 392 { 393 for (; set->cmd; ++set) 394 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 395 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 396 set->cmd2 & CMD2_CLR ? " CLR" : "", 397 set->cmd2 & CMD2_SET ? " SET" : "", 398 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 399 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 400 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 401 } 402 #endif 403 404 /* 405 * Given an array of bitcmd structures, compress by compacting consecutive 406 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 407 * 'g' and 'o' commands continue to be separate. They could probably be 408 * compacted, but it's not worth the effort. 409 */ 410 static void 411 compress_mode(set) 412 register BITCMD *set; 413 { 414 register BITCMD *nset; 415 register int setbits, clrbits, Xbits, op; 416 417 for (nset = set;;) { 418 /* Copy over any 'u', 'g' and 'o' commands. */ 419 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 420 *set++ = *nset++; 421 if (!op) 422 return; 423 } 424 425 for (setbits = clrbits = Xbits = 0;; nset++) { 426 if ((op = nset->cmd) == '-') { 427 clrbits |= nset->bits; 428 setbits &= ~nset->bits; 429 Xbits &= ~nset->bits; 430 } else if (op == '+') { 431 setbits |= nset->bits; 432 clrbits &= ~nset->bits; 433 Xbits &= ~nset->bits; 434 } else if (op == 'X') 435 Xbits |= nset->bits & ~setbits; 436 else 437 break; 438 } 439 if (clrbits) { 440 set->cmd = '-'; 441 set->cmd2 = 0; 442 set->bits = clrbits; 443 set++; 444 } 445 if (setbits) { 446 set->cmd = '+'; 447 set->cmd2 = 0; 448 set->bits = setbits; 449 set++; 450 } 451 if (Xbits) { 452 set->cmd = 'X'; 453 set->cmd2 = 0; 454 set->bits = Xbits; 455 set++; 456 } 457 } 458 } 459