1 /* 2 * Copyright (c) 1989, 1993 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 * %sccs.include.redist.c% 9 */ 10 11 #if defined(LIBC_SCCS) && !defined(lint) 12 static char sccsid[] = "@(#)setmode.c 8.1 (Berkeley) 06/04/93"; 13 #endif /* LIBC_SCCS and not lint */ 14 15 #include <sys/types.h> 16 #include <sys/stat.h> 17 #include <signal.h> 18 #include <errno.h> 19 #include <stddef.h> 20 #ifdef SETMODE_DEBUG 21 #include <stdio.h> 22 #endif 23 #include <stdlib.h> 24 #include <ctype.h> 25 26 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 27 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 28 29 typedef struct bitcmd { 30 char cmd; 31 char cmd2; 32 mode_t bits; 33 } BITCMD; 34 35 #define CMD2_CLR 0x01 36 #define CMD2_SET 0x02 37 #define CMD2_GBITS 0x04 38 #define CMD2_OBITS 0x08 39 #define CMD2_UBITS 0x10 40 41 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 42 static int compress_mode __P((BITCMD *)); 43 #ifdef SETMODE_DEBUG 44 static void dumpmode __P((BITCMD *)); 45 #endif 46 47 /* 48 * Given the old mode and an array of bitcmd structures, apply the operations 49 * described in the bitcmd structures to the old mode, and return the new mode. 50 * Note that there is no '=' command; a strict assignment is just a '-' (clear 51 * bits) followed by a '+' (set bits). 52 */ 53 mode_t 54 getmode(bbox, omode) 55 void *bbox; 56 mode_t omode; 57 { 58 register BITCMD *set; 59 register mode_t newmode, value; 60 61 set = (BITCMD *)bbox; 62 newmode = omode; 63 for (value = 0;; set++) 64 switch(set->cmd) { 65 /* 66 * When copying the user, group or other bits around, we "know" 67 * where the bits are in the mode so that we can do shifts to 68 * copy them around. If we don't use shifts, it gets real 69 * grundgy with lots of single bit checks and bit sets. 70 */ 71 case 'u': 72 value = (newmode & S_IRWXU) >> 6; 73 goto common; 74 75 case 'g': 76 value = (newmode & S_IRWXG) >> 3; 77 goto common; 78 79 case 'o': 80 value = newmode & S_IRWXO; 81 common: if (set->cmd2 & CMD2_CLR) { 82 if (set->cmd2 & CMD2_UBITS) 83 newmode &= ~(S_IRWXU & set->bits); 84 if (set->cmd2 & CMD2_GBITS) 85 newmode &= ~(S_IRWXG & set->bits); 86 if (set->cmd2 & CMD2_OBITS) 87 newmode &= ~(S_IRWXO & set->bits); 88 } 89 if (set->cmd2 & CMD2_SET) { 90 if (set->cmd2 & CMD2_UBITS) 91 newmode |= (value<<6) & set->bits; 92 if (set->cmd2 & CMD2_GBITS) 93 newmode |= (value<<3) & set->bits; 94 if (set->cmd2 & CMD2_OBITS) 95 newmode |= value & set->bits; 96 } 97 break; 98 99 case '+': 100 newmode |= set->bits; 101 break; 102 103 case '-': 104 newmode &= ~set->bits; 105 break; 106 107 case 'X': 108 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 109 newmode |= set->bits; 110 break; 111 112 case '\0': 113 default: 114 #ifdef SETMODE_DEBUG 115 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 116 #endif 117 return (newmode); 118 } 119 } 120 121 #define ADDCMD(a, b, c, d) \ 122 if (set >= endset) { \ 123 register BITCMD *newset; \ 124 setlen += SET_LEN_INCR; \ 125 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 126 if (!saveset) \ 127 return (NULL); \ 128 set = newset + (set - saveset); \ 129 saveset = newset; \ 130 endset = newset + (setlen - 2); \ 131 } \ 132 set = addcmd(set, (a), (b), (c), (d)) 133 134 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 135 136 void * 137 setmode(p) 138 register char *p; 139 { 140 register int perm, who; 141 register char op; 142 BITCMD *set, *saveset, *endset; 143 sigset_t sigset, sigoset; 144 mode_t mask; 145 int permXbits, setlen; 146 147 if (!*p) 148 return (NULL); 149 150 /* 151 * Get a copy of the mask for the permissions that are mask relative. 152 * Flip the bits, we want what's not set. Since it's possible that 153 * the caller is opening files inside a signal handler, protect them 154 * as best we can. 155 */ 156 sigfillset(&sigset); 157 (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset); 158 (void)umask(mask = umask(0)); 159 mask = ~mask; 160 (void)sigprocmask(SIG_SETMASK, &sigoset, NULL); 161 162 setlen = SET_LEN + 2; 163 164 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 165 return (NULL); 166 saveset = set; 167 endset = set + (setlen - 2); 168 169 /* 170 * If an absolute number, get it and return; disallow non-octal digits 171 * or illegal bits. 172 */ 173 if (isdigit(*p)) { 174 perm = (mode_t)strtol(p, (char **)0, 8); 175 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 176 free(saveset); 177 return (NULL); 178 } 179 while (*++p) 180 if (*p < '0' || *p > '7') { 181 free(saveset); 182 return (NULL); 183 } 184 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 185 return (saveset); 186 } 187 188 /* 189 * Build list of structures to set/clear/copy bits as described by 190 * each clause of the symbolic mode. 191 */ 192 for (;;) { 193 /* First, find out which bits might be modified. */ 194 for (who = 0;; ++p) { 195 switch (*p) { 196 case 'a': 197 who |= STANDARD_BITS; 198 break; 199 case 'u': 200 who |= S_ISUID|S_IRWXU; 201 break; 202 case 'g': 203 who |= S_ISGID|S_IRWXG; 204 break; 205 case 'o': 206 who |= S_IRWXO; 207 break; 208 default: 209 goto getop; 210 } 211 } 212 213 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 214 free(saveset); 215 return (NULL); 216 } 217 218 who &= ~S_ISTXT; 219 for (perm = 0, permXbits = 0;; ++p) { 220 switch (*p) { 221 case 'r': 222 perm |= S_IRUSR|S_IRGRP|S_IROTH; 223 break; 224 case 's': 225 /* If only "other" bits ignore set-id. */ 226 if (who & ~S_IRWXO) 227 perm |= S_ISUID|S_ISGID; 228 break; 229 case 't': 230 /* If only "other" bits ignore sticky. */ 231 if (who & ~S_IRWXO) { 232 who |= S_ISTXT; 233 perm |= S_ISTXT; 234 } 235 break; 236 case 'w': 237 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 238 break; 239 case 'X': 240 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 241 break; 242 case 'x': 243 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 244 break; 245 case 'u': 246 case 'g': 247 case 'o': 248 /* 249 * When ever we hit 'u', 'g', or 'o', we have 250 * to flush out any partial mode that we have, 251 * and then do the copying of the mode bits. 252 */ 253 if (perm || op == '=') { 254 ADDCMD(op, who, perm, mask); 255 perm = 0; 256 } 257 if (op == '+' && permXbits) { 258 ADDCMD('X', who, permXbits, mask); 259 permXbits = 0; 260 } 261 ADDCMD(*p, who, op, mask); 262 break; 263 264 default: 265 /* 266 * Add any permissions that we haven't already 267 * done. 268 */ 269 if (perm || op == '=') { 270 ADDCMD(op, who, perm, mask); 271 perm = 0; 272 } 273 if (permXbits) { 274 ADDCMD('X', who, permXbits, mask); 275 permXbits = 0; 276 } 277 goto apply; 278 } 279 } 280 281 apply: if (!*p) 282 break; 283 if (*p != ',') 284 goto getop; 285 ++p; 286 } 287 set->cmd = 0; 288 #ifdef SETMODE_DEBUG 289 (void)printf("Before compress_mode()\n"); 290 dumpmode(saveset); 291 #endif 292 compress_mode(saveset); 293 #ifdef SETMODE_DEBUG 294 (void)printf("After compress_mode()\n"); 295 dumpmode(saveset); 296 #endif 297 return (saveset); 298 } 299 300 static BITCMD * 301 addcmd(set, op, who, oparg, mask) 302 BITCMD *set; 303 register int oparg, who; 304 register int op; 305 u_int mask; 306 { 307 switch (op) { 308 case '+': 309 case 'X': 310 set->cmd = op; 311 set->bits = (who ? who : mask) & oparg; 312 break; 313 314 case '-': 315 set->cmd = '-'; 316 set->bits = (who ? who : (S_IRWXU|S_IRWXG|S_IRWXO)) & oparg; 317 break; 318 319 case '=': 320 set->cmd = '-'; 321 if (!who) { 322 set->bits = STANDARD_BITS; 323 who = mask; 324 } else 325 set->bits = who; 326 set++; 327 328 set->cmd = '+'; 329 set->bits = who & oparg; 330 break; 331 case 'u': 332 case 'g': 333 case 'o': 334 set->cmd = op; 335 if (who) { 336 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 337 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 338 ((who & S_IROTH) ? CMD2_OBITS : 0); 339 set->bits = ~0; 340 } else { 341 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 342 set->bits = mask; 343 } 344 345 if (oparg == '+') 346 set->cmd2 |= CMD2_SET; 347 else if (oparg == '-') 348 set->cmd2 |= CMD2_CLR; 349 else if (oparg == '=') 350 set->cmd2 |= CMD2_SET|CMD2_CLR; 351 break; 352 } 353 return (set + 1); 354 } 355 356 #ifdef SETMODE_DEBUG 357 static void 358 dumpmode(set) 359 register BITCMD *set; 360 { 361 for (; set->cmd; ++set) 362 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 363 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 364 set->cmd2 & CMD2_CLR ? " CLR" : "", 365 set->cmd2 & CMD2_SET ? " SET" : "", 366 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 367 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 368 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 369 } 370 #endif 371 372 /* 373 * Given an array of bitcmd structures, compress by compacting consecutive 374 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 375 * 'g' and 'o' commands continue to be separate. They could probably be 376 * compacted, but it's not worth the effort. 377 */ 378 static int 379 compress_mode(set) 380 register BITCMD *set; 381 { 382 register BITCMD *nset; 383 register int setbits, clrbits, Xbits, op; 384 385 for (nset = set;;) { 386 /* Copy over any 'u', 'g' and 'o' commands. */ 387 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 388 *set++ = *nset++; 389 if (!op) 390 return; 391 } 392 393 for (setbits = clrbits = Xbits = 0;; nset++) { 394 if ((op = nset->cmd) == '-') { 395 clrbits |= nset->bits; 396 setbits &= ~nset->bits; 397 Xbits &= ~nset->bits; 398 } else if (op == '+') { 399 setbits |= nset->bits; 400 clrbits &= ~nset->bits; 401 Xbits &= ~nset->bits; 402 } else if (op == 'X') 403 Xbits |= nset->bits & ~setbits; 404 else 405 break; 406 } 407 if (clrbits) { 408 set->cmd = '-'; 409 set->cmd2 = 0; 410 set->bits = clrbits; 411 set++; 412 } 413 if (setbits) { 414 set->cmd = '+'; 415 set->cmd2 = 0; 416 set->bits = setbits; 417 set++; 418 } 419 if (Xbits) { 420 set->cmd = 'X'; 421 set->cmd2 = 0; 422 set->bits = Xbits; 423 set++; 424 } 425 } 426 } 427