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