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 5.4 (Berkeley) 01/09/91"; 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(set, omode) 43 register struct bitcmd *set; 44 mode_t omode; 45 { 46 register mode_t newmode, value; 47 48 newmode = omode; 49 for (value = 0;; set++) 50 switch(set->cmd) { 51 /* 52 * When copying the user, group or other bits around, we "know" 53 * where the bit are in the mode so that we can do shifts to 54 * copy them around. If we don't use shifts, it gets real 55 * grundgy with lots of single bit checks and bit sets. 56 */ 57 case 'u': 58 value = (newmode & S_IRWXU) >> 6; 59 goto common; 60 61 case 'g': 62 value = (newmode & S_IRWXG) >> 3; 63 goto common; 64 65 case 'o': 66 value = newmode & S_IRWXO; 67 common: 68 if (set->cmd2 & CMD2_CLR) { 69 if (set->cmd2 & CMD2_UBITS) 70 newmode &= ~(S_IRWXU & set->bits); 71 if (set->cmd2 & CMD2_GBITS) 72 newmode &= ~(S_IRWXG & set->bits); 73 if (set->cmd2 & CMD2_OBITS) 74 newmode &= ~(S_IRWXO & set->bits); 75 } 76 if (set->cmd2 & CMD2_SET) { 77 if (set->cmd2 & CMD2_UBITS) 78 newmode |= (value<<6) & set->bits; 79 if (set->cmd2 & CMD2_GBITS) 80 newmode |= (value<<3) & set->bits; 81 if (set->cmd2 & CMD2_OBITS) 82 newmode |= value & set->bits; 83 } 84 break; 85 86 case '+': 87 newmode |= set->bits; 88 break; 89 90 case '-': 91 newmode &= ~set->bits; 92 break; 93 94 case 'X': 95 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 96 newmode |= set->bits; 97 break; 98 99 case '\0': 100 default: 101 #ifdef SETMODE_DEBUG 102 (void)printf("getmode(, %04o) -> %04o\n", 103 omode, newmode); 104 #endif 105 return(newmode); 106 } 107 } 108 109 #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 110 111 static struct bitcmd * 112 addcmd(set, op, who, oparg, mask) 113 struct bitcmd *set; 114 register int oparg, who; 115 register int op; 116 mode_t mask; 117 { 118 switch (op) { 119 case '+': 120 case 'X': 121 set->cmd = op; 122 set->bits = (who ? who : mask) & oparg; 123 break; 124 125 case '-': 126 set->cmd = '-'; 127 set->bits = (who ? who : (S_IRWXU|S_IRWXG|S_IRWXO)) & oparg; 128 break; 129 130 case '=': 131 set->cmd = '-'; 132 if (!who) { 133 set->bits = STANDARD_BITS; 134 who = mask; 135 } else 136 set->bits = who; 137 set++; 138 139 set->cmd = '+'; 140 set->bits = who & oparg; 141 break; 142 case 'u': 143 case 'g': 144 case 'o': 145 set->cmd = op; 146 if (who) { 147 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 148 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 149 ((who & S_IROTH) ? CMD2_OBITS : 0); 150 set->bits = ~0; 151 } else { 152 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 153 set->bits = mask; 154 } 155 156 if (oparg == '+') 157 set->cmd2 |= CMD2_SET; 158 else if (oparg == '-') 159 set->cmd2 |= CMD2_CLR; 160 else if (oparg == '=') 161 set->cmd2 |= CMD2_SET|CMD2_CLR; 162 break; 163 } 164 return(set+1); 165 } 166 167 #define ADDCMD(a, b, c, d) \ 168 if (set >= endset) { \ 169 register struct bitcmd *newset; \ 170 setlen += SET_LEN_INCR; \ 171 newset = realloc(saveset, sizeof(struct bitcmd) * setlen); \ 172 if (!saveset) \ 173 return(NULL); \ 174 set = newset + (set - saveset); \ 175 saveset = newset; \ 176 endset = newset + (setlen - 2); \ 177 } \ 178 set = addcmd(set, (a), (b), (c), (d)) 179 180 struct bitcmd * 181 setmode(p) 182 register char *p; 183 { 184 register int perm, who; 185 register char op; 186 mode_t mask; 187 struct bitcmd *set, *saveset, *endset; 188 int permXbits, setlen; 189 190 /* 191 * Get a copy of the mask for the permissions that are mask relative. 192 * Flip the bits, we want what's not set. 193 */ 194 (void)umask(mask = umask(0)); 195 mask = ~mask; 196 197 setlen = SET_LEN + 2; 198 199 set = (struct bitcmd *)malloc((u_int)(sizeof(struct bitcmd) * setlen)); 200 if (!set) 201 return(NULL); 202 saveset = set; 203 endset = set + (setlen - 2); 204 205 /* 206 * If an absolute number, get it and return; disallow non-octal digits 207 * or illegal bits. 208 */ 209 if (isdigit(*p)) { 210 perm = (mode_t)strtol(p, (char **)0, 8); 211 if (perm & ~(STANDARD_BITS|S_ISTXT)) { 212 free(saveset); 213 return(NULL); 214 } 215 while (*++p) 216 if (*p < '0' || *p > '7') { 217 free(saveset); 218 return(NULL); 219 } 220 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 221 return(saveset); 222 } 223 224 if (!*p) { 225 free(saveset); 226 return(NULL); 227 } 228 /* 229 * Build list of structures to set/clear/copy bits as described by 230 * each clause of the symbolic mode. 231 */ 232 for (;;) { 233 /* First, find out which bits might be modified. */ 234 for (who = 0;; ++p) { 235 switch (*p) { 236 case 'a': 237 who |= STANDARD_BITS; 238 break; 239 case 'u': 240 who |= S_ISUID|S_IRWXU; 241 break; 242 case 'g': 243 who |= S_ISGID|S_IRWXG; 244 break; 245 case 'o': 246 who |= S_IRWXO; 247 break; 248 default: 249 goto getop; 250 } 251 } 252 getop: 253 254 if ((op = *p++) != '+' && op != '-' && op != '=') { 255 free(saveset); 256 return(NULL); 257 } 258 259 who &= ~S_ISTXT; 260 for (perm = 0, permXbits = 0;; ++p) { 261 switch (*p) { 262 case 'r': 263 perm |= S_IRUSR|S_IRGRP|S_IROTH; 264 break; 265 case 's': 266 /* If only "other" bits ignore set-id. */ 267 if (who & ~S_IRWXO) 268 perm |= S_ISUID|S_ISGID; 269 break; 270 case 't': 271 /* If only "other" bits ignore sticky. */ 272 if (who & ~S_IRWXO) { 273 who |= S_ISTXT; 274 perm |= S_ISTXT; 275 } 276 break; 277 case 'w': 278 perm |= S_IWUSR|S_IWGRP|S_IWOTH; 279 break; 280 case 'X': 281 permXbits = S_IXUSR|S_IXGRP|S_IXOTH; 282 break; 283 case 'x': 284 perm |= S_IXUSR|S_IXGRP|S_IXOTH; 285 break; 286 case 'u': 287 case 'g': 288 case 'o': 289 /* 290 * When ever we hit 'u', 'g', or 'o', we have 291 * to flush out any partial mode that we have, 292 * and then do the copying of the mode bits. 293 */ 294 if (perm) { 295 ADDCMD(op, who, perm, mask); 296 perm = 0; 297 } 298 if (op == '+' && permXbits) { 299 ADDCMD('X', who, permXbits, mask); 300 permXbits = 0; 301 } 302 ADDCMD(*p, who, op, mask); 303 break; 304 305 default: 306 /* 307 * Add any permissions that we haven't already 308 * done. 309 */ 310 if (perm) { 311 ADDCMD(op, who, perm, mask); 312 perm = 0; 313 } 314 if (permXbits) { 315 ADDCMD('X', who, permXbits, mask); 316 permXbits = 0; 317 } 318 goto apply; 319 } 320 } 321 322 apply: if (!*p) 323 break; 324 if (*p != ',') 325 goto getop; 326 ++p; 327 } 328 set->cmd = 0; 329 #ifdef SETMODE_DEBUG 330 (void)printf("Before compress_mode()\n"); 331 dumpmode(saveset); 332 #endif 333 compress_mode(saveset); 334 #ifdef SETMODE_DEBUG 335 (void)printf("After compress_mode()\n"); 336 dumpmode(saveset); 337 #endif 338 return(saveset); 339 } 340 341 #ifdef SETMODE_DEBUG 342 dumpmode(set) 343 register struct bitcmd *set; 344 { 345 for (; set->cmd; ++set) 346 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 347 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 348 set->cmd2 & CMD2_CLR ? " CLR" : "", 349 set->cmd2 & CMD2_SET ? " SET" : "", 350 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 351 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 352 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 353 } 354 #endif 355 356 /* 357 * Given an array of bitcmd structures, compress by compacting consecutive 358 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 359 * 'g' and 'o' commands continue to be separate. They could probably be 360 * compacted, but it's not worth the effort. 361 */ 362 static 363 compress_mode(set) 364 register struct bitcmd *set; 365 { 366 register struct bitcmd *nset; 367 register int setbits, clrbits, Xbits, op; 368 369 for (nset = set;;) { 370 /* Copy over any 'u', 'g' and 'o' commands. */ 371 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 372 *set++ = *nset++; 373 if (!op) 374 return; 375 } 376 377 for (setbits = clrbits = Xbits = 0;; nset++) { 378 if ((op = nset->cmd) == '-') { 379 clrbits |= nset->bits; 380 setbits &= ~nset->bits; 381 Xbits &= ~nset->bits; 382 } else if (op == '+') { 383 setbits |= nset->bits; 384 clrbits &= ~nset->bits; 385 Xbits &= ~nset->bits; 386 } else if (op == 'X') 387 Xbits |= nset->bits & ~setbits; 388 else 389 break; 390 } 391 if (clrbits) { 392 set->cmd = '-'; 393 set->cmd2 = 0; 394 set->bits = clrbits; 395 set++; 396 } 397 if (setbits) { 398 set->cmd = '+'; 399 set->cmd2 = 0; 400 set->bits = setbits; 401 set++; 402 } 403 if (Xbits) { 404 set->cmd = 'X'; 405 set->cmd2 = 0; 406 set->bits = Xbits; 407 set++; 408 } 409 } 410 } 411