1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)setmode.c 5.7 (Berkeley) 03/02/92"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/types.h> 13 #include <sys/stat.h> 14 #include <errno.h> 15 #define SETMODE_DEBUG 16 #ifdef SETMODE_DEBUG 17 #include <stdio.h> 18 #endif 19 #include <stdlib.h> 20 #include <ctype.h> 21 22 #define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 23 #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 24 25 typedef struct bitcmd { 26 char cmd; 27 char cmd2; 28 mode_t bits; 29 } BITCMD; 30 31 #define CMD2_CLR 0x01 32 #define CMD2_SET 0x02 33 #define CMD2_GBITS 0x04 34 #define CMD2_OBITS 0x08 35 #define CMD2_UBITS 0x10 36 37 static BITCMD *addcmd __P((BITCMD *, int, int, int, u_int)); 38 static int compress_mode __P((BITCMD *)); 39 #ifdef SETMODE_DEBUG 40 static void dumpmode __P((BITCMD *)); 41 #endif 42 43 /* 44 * Given the old mode and an array of bitcmd structures, apply the operations 45 * described in the bitcmd structures to the old mode, and return the new mode. 46 * Note that there is no '=' command; a strict assignment is just a '-' (clear 47 * bits) followed by a '+' (set bits). 48 */ 49 mode_t 50 getmode(bbox, omode) 51 void *bbox; 52 mode_t omode; 53 { 54 register BITCMD *set; 55 register mode_t newmode, value; 56 57 set = (BITCMD *)bbox; 58 newmode = omode; 59 for (value = 0;; set++) 60 switch(set->cmd) { 61 /* 62 * When copying the user, group or other bits around, we "know" 63 * where the bits are in the mode so that we can do shifts to 64 * copy them around. If we don't use shifts, it gets real 65 * grundgy with lots of single bit checks and bit sets. 66 */ 67 case 'u': 68 value = (newmode & S_IRWXU) >> 6; 69 goto common; 70 71 case 'g': 72 value = (newmode & S_IRWXG) >> 3; 73 goto common; 74 75 case 'o': 76 value = newmode & S_IRWXO; 77 common: if (set->cmd2 & CMD2_CLR) { 78 if (set->cmd2 & CMD2_UBITS) 79 newmode &= ~(S_IRWXU & set->bits); 80 if (set->cmd2 & CMD2_GBITS) 81 newmode &= ~(S_IRWXG & set->bits); 82 if (set->cmd2 & CMD2_OBITS) 83 newmode &= ~(S_IRWXO & set->bits); 84 } 85 if (set->cmd2 & CMD2_SET) { 86 if (set->cmd2 & CMD2_UBITS) 87 newmode |= (value<<6) & set->bits; 88 if (set->cmd2 & CMD2_GBITS) 89 newmode |= (value<<3) & set->bits; 90 if (set->cmd2 & CMD2_OBITS) 91 newmode |= value & set->bits; 92 } 93 break; 94 95 case '+': 96 newmode |= set->bits; 97 break; 98 99 case '-': 100 newmode &= ~set->bits; 101 break; 102 103 case 'X': 104 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 105 newmode |= set->bits; 106 break; 107 108 case '\0': 109 default: 110 #ifdef SETMODE_DEBUG 111 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 112 #endif 113 return (newmode); 114 } 115 } 116 117 #define ADDCMD(a, b, c, d) \ 118 if (set >= endset) { \ 119 register BITCMD *newset; \ 120 setlen += SET_LEN_INCR; \ 121 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 122 if (!saveset) \ 123 return (NULL); \ 124 set = newset + (set - saveset); \ 125 saveset = newset; \ 126 endset = newset + (setlen - 2); \ 127 } \ 128 set = addcmd(set, (a), (b), (c), (d)) 129 130 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 131 132 void * 133 setmode(p) 134 register char *p; 135 { 136 register int perm, who; 137 register char op; 138 BITCMD *set, *saveset, *endset; 139 mode_t mask; 140 int permXbits, setlen; 141 142 if (!*p) 143 return (NULL); 144 145 /* 146 * Get a copy of the mask for the permissions that are mask relative. 147 * Flip the bits, we want what's not set. 148 */ 149 (void)umask(mask = umask(0)); 150 mask = ~mask; 151 152 setlen = SET_LEN + 2; 153 154 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 155 return (NULL); 156 saveset = set; 157 endset = set + (setlen - 2); 158 159 /* 160 * If an absolute number, get it and return; disallow non-octal digits 161 * or illegal bits. 162 */ 163 if (isdigit(*p)) { 164 perm = (mode_t)strtol(p, (char **)0, 8); 165 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 166 free(saveset); 167 return (NULL); 168 } 169 while (*++p) 170 if (*p < '0' || *p > '7') { 171 free(saveset); 172 return (NULL); 173 } 174 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 175 return (saveset); 176 } 177 178 /* 179 * Build list of structures to set/clear/copy bits as described by 180 * each clause of the symbolic mode. 181 */ 182 for (;;) { 183 /* First, find out which bits might be modified. */ 184 for (who = 0;; ++p) { 185 switch (*p) { 186 case 'a': 187 who |= STANDARD_BITS; 188 break; 189 case 'u': 190 who |= S_ISUID|S_IRWXU; 191 break; 192 case 'g': 193 who |= S_ISGID|S_IRWXG; 194 break; 195 case 'o': 196 who |= S_IRWXO; 197 break; 198 default: 199 goto getop; 200 } 201 } 202 203 getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 204 free(saveset); 205 return (NULL); 206 } 207 208 who &= ~S_ISTXT; 209 for (perm = 0, permXbits = 0;; ++p) { 210 switch (*p) { 211 case 'r': 212 perm |= S_IRUSR|S_IRGRP|S_IROTH; 213 break; 214 case 's': 215 /* If only "other" bits ignore set-id. */ 216 if (who & ~S_IRWXO) 217 perm |= S_ISUID|S_ISGID; 218 break; 219 case 't': 220 /* If only "other" bits ignore sticky. */ 221 if (who & ~S_IRWXO) { 222 who |= S_ISTXT; 223 perm |= S_ISTXT; 224 } 225 break; 226 case 'w': 227 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 228 break; 229 case 'X': 230 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 231 break; 232 case 'x': 233 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 234 break; 235 case 'u': 236 case 'g': 237 case 'o': 238 /* 239 * When ever we hit 'u', 'g', or 'o', we have 240 * to flush out any partial mode that we have, 241 * and then do the copying of the mode bits. 242 */ 243 if (perm) { 244 ADDCMD(op, who, perm, mask); 245 perm = 0; 246 } 247 if (op == '+' && permXbits) { 248 ADDCMD('X', who, permXbits, mask); 249 permXbits = 0; 250 } 251 ADDCMD(*p, who, op, mask); 252 break; 253 254 default: 255 /* 256 * Add any permissions that we haven't already 257 * done. 258 */ 259 if (perm) { 260 ADDCMD(op, who, perm, mask); 261 perm = 0; 262 } 263 if (permXbits) { 264 ADDCMD('X', who, permXbits, mask); 265 permXbits = 0; 266 } 267 goto apply; 268 } 269 } 270 271 apply: if (!*p) 272 break; 273 if (*p != ',') 274 goto getop; 275 ++p; 276 } 277 set->cmd = 0; 278 #ifdef SETMODE_DEBUG 279 (void)printf("Before compress_mode()\n"); 280 dumpmode(saveset); 281 #endif 282 compress_mode(saveset); 283 #ifdef SETMODE_DEBUG 284 (void)printf("After compress_mode()\n"); 285 dumpmode(saveset); 286 #endif 287 return (saveset); 288 } 289 290 static BITCMD * 291 addcmd(set, op, who, oparg, mask) 292 BITCMD *set; 293 register int oparg, who; 294 register int op; 295 u_int mask; 296 { 297 switch (op) { 298 case '+': 299 case 'X': 300 set->cmd = op; 301 set->bits = (who ? who : mask) & oparg; 302 break; 303 304 case '-': 305 set->cmd = '-'; 306 set->bits = (who ? who : (S_IRWXU|S_IRWXG|S_IRWXO)) & oparg; 307 break; 308 309 case '=': 310 set->cmd = '-'; 311 if (!who) { 312 set->bits = STANDARD_BITS; 313 who = mask; 314 } else 315 set->bits = who; 316 set++; 317 318 set->cmd = '+'; 319 set->bits = who & oparg; 320 break; 321 case 'u': 322 case 'g': 323 case 'o': 324 set->cmd = op; 325 if (who) { 326 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 327 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 328 ((who & S_IROTH) ? CMD2_OBITS : 0); 329 set->bits = ~0; 330 } else { 331 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 332 set->bits = mask; 333 } 334 335 if (oparg == '+') 336 set->cmd2 |= CMD2_SET; 337 else if (oparg == '-') 338 set->cmd2 |= CMD2_CLR; 339 else if (oparg == '=') 340 set->cmd2 |= CMD2_SET|CMD2_CLR; 341 break; 342 } 343 return (set + 1); 344 } 345 346 #ifdef SETMODE_DEBUG 347 static void 348 dumpmode(set) 349 register BITCMD *set; 350 { 351 for (; set->cmd; ++set) 352 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 353 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 354 set->cmd2 & CMD2_CLR ? " CLR" : "", 355 set->cmd2 & CMD2_SET ? " SET" : "", 356 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 357 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 358 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 359 } 360 #endif 361 362 /* 363 * Given an array of bitcmd structures, compress by compacting consecutive 364 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 365 * 'g' and 'o' commands continue to be separate. They could probably be 366 * compacted, but it's not worth the effort. 367 */ 368 static int 369 compress_mode(set) 370 register BITCMD *set; 371 { 372 register BITCMD *nset; 373 register int setbits, clrbits, Xbits, op; 374 375 for (nset = set;;) { 376 /* Copy over any 'u', 'g' and 'o' commands. */ 377 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 378 *set++ = *nset++; 379 if (!op) 380 return; 381 } 382 383 for (setbits = clrbits = Xbits = 0;; nset++) { 384 if ((op = nset->cmd) == '-') { 385 clrbits |= nset->bits; 386 setbits &= ~nset->bits; 387 Xbits &= ~nset->bits; 388 } else if (op == '+') { 389 setbits |= nset->bits; 390 clrbits &= ~nset->bits; 391 Xbits &= ~nset->bits; 392 } else if (op == 'X') 393 Xbits |= nset->bits & ~setbits; 394 else 395 break; 396 } 397 if (clrbits) { 398 set->cmd = '-'; 399 set->cmd2 = 0; 400 set->bits = clrbits; 401 set++; 402 } 403 if (setbits) { 404 set->cmd = '+'; 405 set->cmd2 = 0; 406 set->bits = setbits; 407 set++; 408 } 409 if (Xbits) { 410 set->cmd = 'X'; 411 set->cmd2 = 0; 412 set->bits = Xbits; 413 set++; 414 } 415 } 416 } 417