1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * 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 5.10 (Berkeley) 03/16/92"; 13 #endif /* LIBC_SCCS and not lint */ 14 15 #include <sys/types.h> 16 #include <sys/stat.h> 17 #include <errno.h> 18 #include <stddef.h> 19 #ifdef SETMODE_DEBUG 20 #include <stdio.h> 21 #endif 22 #include <stdlib.h> 23 #include <ctype.h> 24 25 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 26 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 27 28 typedef struct bitcmd { 29 char cmd; 30 char cmd2; 31 mode_t bits; 32 } BITCMD; 33 34 #define CMD2_CLR 0x01 35 #define CMD2_SET 0x02 36 #define CMD2_GBITS 0x04 37 #define CMD2_OBITS 0x08 38 #define CMD2_UBITS 0x10 39 40 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 41 static int compress_mode __P((BITCMD *)); 42 #ifdef SETMODE_DEBUG 43 static void dumpmode __P((BITCMD *)); 44 #endif 45 46 /* 47 * Given the old mode and an array of bitcmd structures, apply the operations 48 * described in the bitcmd structures to the old mode, and return the new mode. 49 * Note that there is no '=' command; a strict assignment is just a '-' (clear 50 * bits) followed by a '+' (set bits). 51 */ 52 mode_t 53 getmode(bbox, omode) 54 void *bbox; 55 mode_t omode; 56 { 57 register BITCMD *set; 58 register mode_t newmode, value; 59 60 set = (BITCMD *)bbox; 61 newmode = omode; 62 for (value = 0;; set++) 63 switch(set->cmd) { 64 /* 65 * When copying the user, group or other bits around, we "know" 66 * where the bits are in the mode so that we can do shifts to 67 * copy them around. If we don't use shifts, it gets real 68 * grundgy with lots of single bit checks and bit sets. 69 */ 70 case 'u': 71 value = (newmode & S_IRWXU) >> 6; 72 goto common; 73 74 case 'g': 75 value = (newmode & S_IRWXG) >> 3; 76 goto common; 77 78 case 'o': 79 value = newmode & S_IRWXO; 80 common: if (set->cmd2 & CMD2_CLR) { 81 if (set->cmd2 & CMD2_UBITS) 82 newmode &= ~(S_IRWXU & set->bits); 83 if (set->cmd2 & CMD2_GBITS) 84 newmode &= ~(S_IRWXG & set->bits); 85 if (set->cmd2 & CMD2_OBITS) 86 newmode &= ~(S_IRWXO & set->bits); 87 } 88 if (set->cmd2 & CMD2_SET) { 89 if (set->cmd2 & CMD2_UBITS) 90 newmode |= (value<<6) & set->bits; 91 if (set->cmd2 & CMD2_GBITS) 92 newmode |= (value<<3) & set->bits; 93 if (set->cmd2 & CMD2_OBITS) 94 newmode |= value & set->bits; 95 } 96 break; 97 98 case '+': 99 newmode |= set->bits; 100 break; 101 102 case '-': 103 newmode &= ~set->bits; 104 break; 105 106 case 'X': 107 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 108 newmode |= set->bits; 109 break; 110 111 case '\0': 112 default: 113 #ifdef SETMODE_DEBUG 114 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 115 #endif 116 return (newmode); 117 } 118 } 119 120 #define ADDCMD(a, b, c, d) \ 121 if (set >= endset) { \ 122 register BITCMD *newset; \ 123 setlen += SET_LEN_INCR; \ 124 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 125 if (!saveset) \ 126 return (NULL); \ 127 set = newset + (set - saveset); \ 128 saveset = newset; \ 129 endset = newset + (setlen - 2); \ 130 } \ 131 set = addcmd(set, (a), (b), (c), (d)) 132 133 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 134 135 void * 136 setmode(p) 137 register char *p; 138 { 139 register int perm, who; 140 register char op; 141 BITCMD *set, *saveset, *endset; 142 mode_t mask; 143 int permXbits, setlen; 144 145 if (!*p) 146 return (NULL); 147 148 /* 149 * Get a copy of the mask for the permissions that are mask relative. 150 * Flip the bits, we want what's not set. 151 */ 152 (void)umask(mask = umask(0)); 153 mask = ~mask; 154 155 setlen = SET_LEN + 2; 156 157 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 158 return (NULL); 159 saveset = set; 160 endset = set + (setlen - 2); 161 162 /* 163 * If an absolute number, get it and return; disallow non-octal digits 164 * or illegal bits. 165 */ 166 if (isdigit(*p)) { 167 perm = (mode_t)strtol(p, (char **)0, 8); 168 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 169 free(saveset); 170 return (NULL); 171 } 172 while (*++p) 173 if (*p < '0' || *p > '7') { 174 free(saveset); 175 return (NULL); 176 } 177 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 178 return (saveset); 179 } 180 181 /* 182 * Build list of structures to set/clear/copy bits as described by 183 * each clause of the symbolic mode. 184 */ 185 for (;;) { 186 /* First, find out which bits might be modified. */ 187 for (who = 0;; ++p) { 188 switch (*p) { 189 case 'a': 190 who |= STANDARD_BITS; 191 break; 192 case 'u': 193 who |= S_ISUID|S_IRWXU; 194 break; 195 case 'g': 196 who |= S_ISGID|S_IRWXG; 197 break; 198 case 'o': 199 who |= S_IRWXO; 200 break; 201 default: 202 goto getop; 203 } 204 } 205 206 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 207 free(saveset); 208 return (NULL); 209 } 210 211 who &= ~S_ISTXT; 212 for (perm = 0, permXbits = 0;; ++p) { 213 switch (*p) { 214 case 'r': 215 perm |= S_IRUSR|S_IRGRP|S_IROTH; 216 break; 217 case 's': 218 /* If only "other" bits ignore set-id. */ 219 if (who & ~S_IRWXO) 220 perm |= S_ISUID|S_ISGID; 221 break; 222 case 't': 223 /* If only "other" bits ignore sticky. */ 224 if (who & ~S_IRWXO) { 225 who |= S_ISTXT; 226 perm |= S_ISTXT; 227 } 228 break; 229 case 'w': 230 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 231 break; 232 case 'X': 233 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 234 break; 235 case 'x': 236 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 237 break; 238 case 'u': 239 case 'g': 240 case 'o': 241 /* 242 * When ever we hit 'u', 'g', or 'o', we have 243 * to flush out any partial mode that we have, 244 * and then do the copying of the mode bits. 245 */ 246 if (perm || op == '=') { 247 ADDCMD(op, who, perm, mask); 248 perm = 0; 249 } 250 if (op == '+' && permXbits) { 251 ADDCMD('X', who, permXbits, mask); 252 permXbits = 0; 253 } 254 ADDCMD(*p, who, op, mask); 255 break; 256 257 default: 258 /* 259 * Add any permissions that we haven't already 260 * done. 261 */ 262 if (perm || op == '=') { 263 ADDCMD(op, who, perm, mask); 264 perm = 0; 265 } 266 if (permXbits) { 267 ADDCMD('X', who, permXbits, mask); 268 permXbits = 0; 269 } 270 goto apply; 271 } 272 } 273 274 apply: if (!*p) 275 break; 276 if (*p != ',') 277 goto getop; 278 ++p; 279 } 280 set->cmd = 0; 281 #ifdef SETMODE_DEBUG 282 (void)printf("Before compress_mode()\n"); 283 dumpmode(saveset); 284 #endif 285 compress_mode(saveset); 286 #ifdef SETMODE_DEBUG 287 (void)printf("After compress_mode()\n"); 288 dumpmode(saveset); 289 #endif 290 return (saveset); 291 } 292 293 static BITCMD * 294 addcmd(set, op, who, oparg, mask) 295 BITCMD *set; 296 register int oparg, who; 297 register int op; 298 u_int mask; 299 { 300 switch (op) { 301 case '+': 302 case 'X': 303 set->cmd = op; 304 set->bits = (who ? who : mask) & oparg; 305 break; 306 307 case '-': 308 set->cmd = '-'; 309 set->bits = (who ? who : (S_IRWXU|S_IRWXG|S_IRWXO)) & oparg; 310 break; 311 312 case '=': 313 set->cmd = '-'; 314 if (!who) { 315 set->bits = STANDARD_BITS; 316 who = mask; 317 } else 318 set->bits = who; 319 set++; 320 321 set->cmd = '+'; 322 set->bits = who & oparg; 323 break; 324 case 'u': 325 case 'g': 326 case 'o': 327 set->cmd = op; 328 if (who) { 329 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 330 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 331 ((who & S_IROTH) ? CMD2_OBITS : 0); 332 set->bits = ~0; 333 } else { 334 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 335 set->bits = mask; 336 } 337 338 if (oparg == '+') 339 set->cmd2 |= CMD2_SET; 340 else if (oparg == '-') 341 set->cmd2 |= CMD2_CLR; 342 else if (oparg == '=') 343 set->cmd2 |= CMD2_SET|CMD2_CLR; 344 break; 345 } 346 return (set + 1); 347 } 348 349 #ifdef SETMODE_DEBUG 350 static void 351 dumpmode(set) 352 register BITCMD *set; 353 { 354 for (; set->cmd; ++set) 355 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 356 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 357 set->cmd2 & CMD2_CLR ? " CLR" : "", 358 set->cmd2 & CMD2_SET ? " SET" : "", 359 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 360 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 361 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 362 } 363 #endif 364 365 /* 366 * Given an array of bitcmd structures, compress by compacting consecutive 367 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 368 * 'g' and 'o' commands continue to be separate. They could probably be 369 * compacted, but it's not worth the effort. 370 */ 371 static int 372 compress_mode(set) 373 register BITCMD *set; 374 { 375 register BITCMD *nset; 376 register int setbits, clrbits, Xbits, op; 377 378 for (nset = set;;) { 379 /* Copy over any 'u', 'g' and 'o' commands. */ 380 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 381 *set++ = *nset++; 382 if (!op) 383 return; 384 } 385 386 for (setbits = clrbits = Xbits = 0;; nset++) { 387 if ((op = nset->cmd) == '-') { 388 clrbits |= nset->bits; 389 setbits &= ~nset->bits; 390 Xbits &= ~nset->bits; 391 } else if (op == '+') { 392 setbits |= nset->bits; 393 clrbits &= ~nset->bits; 394 Xbits &= ~nset->bits; 395 } else if (op == 'X') 396 Xbits |= nset->bits & ~setbits; 397 else 398 break; 399 } 400 if (clrbits) { 401 set->cmd = '-'; 402 set->cmd2 = 0; 403 set->bits = clrbits; 404 set++; 405 } 406 if (setbits) { 407 set->cmd = '+'; 408 set->cmd2 = 0; 409 set->bits = setbits; 410 set++; 411 } 412 if (Xbits) { 413 set->cmd = 'X'; 414 set->cmd2 = 0; 415 set->bits = Xbits; 416 set++; 417 } 418 } 419 } 420