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