1/* 2 * Copyright (c) 1989, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Dave Borman at Cray Research, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#if defined(LIBC_SCCS) && !defined(lint) 34static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94"; 35#endif /* LIBC_SCCS and not lint */ 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD: releng/10.2/lib/libc/gen/setmode.c 287872 2015-09-16 20:59:41Z delphij $"); 38 39#include "namespace.h" 40#include <sys/types.h> 41#include <sys/stat.h> 42 43#include <ctype.h> 44#include <errno.h> 45#include <limits.h> 46#include <signal.h> 47#include <stddef.h> 48#include <stdlib.h> 49#include <unistd.h> 50 51#ifdef SETMODE_DEBUG 52#include <stdio.h> 53#endif 54#include "un-namespace.h" 55#include "libc_private.h" 56 57#define SET_LEN 6 /* initial # of bitcmd struct to malloc */ 58#define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */ 59 60typedef struct bitcmd { 61 char cmd; 62 char cmd2; 63 mode_t bits; 64} BITCMD; 65 66#define CMD2_CLR 0x01 67#define CMD2_SET 0x02 68#define CMD2_GBITS 0x04 69#define CMD2_OBITS 0x08 70#define CMD2_UBITS 0x10 71 72static BITCMD *addcmd(BITCMD *, mode_t, mode_t, mode_t, mode_t); 73static void compress_mode(BITCMD *); 74#ifdef SETMODE_DEBUG 75static void dumpmode(BITCMD *); 76#endif 77 78/* 79 * Given the old mode and an array of bitcmd structures, apply the operations 80 * described in the bitcmd structures to the old mode, and return the new mode. 81 * Note that there is no '=' command; a strict assignment is just a '-' (clear 82 * bits) followed by a '+' (set bits). 83 */ 84mode_t 85getmode(const void *bbox, mode_t omode) 86{ 87 const BITCMD *set; 88 mode_t clrval, newmode, value; 89 90 set = (const BITCMD *)bbox; 91 newmode = omode; 92 for (value = 0;; set++) 93 switch(set->cmd) { 94 /* 95 * When copying the user, group or other bits around, we "know" 96 * where the bits are in the mode so that we can do shifts to 97 * copy them around. If we don't use shifts, it gets real 98 * grundgy with lots of single bit checks and bit sets. 99 */ 100 case 'u': 101 value = (newmode & S_IRWXU) >> 6; 102 goto common; 103 104 case 'g': 105 value = (newmode & S_IRWXG) >> 3; 106 goto common; 107 108 case 'o': 109 value = newmode & S_IRWXO; 110common: if (set->cmd2 & CMD2_CLR) { 111 clrval = 112 (set->cmd2 & CMD2_SET) ? S_IRWXO : value; 113 if (set->cmd2 & CMD2_UBITS) 114 newmode &= ~((clrval<<6) & set->bits); 115 if (set->cmd2 & CMD2_GBITS) 116 newmode &= ~((clrval<<3) & set->bits); 117 if (set->cmd2 & CMD2_OBITS) 118 newmode &= ~(clrval & set->bits); 119 } 120 if (set->cmd2 & CMD2_SET) { 121 if (set->cmd2 & CMD2_UBITS) 122 newmode |= (value<<6) & set->bits; 123 if (set->cmd2 & CMD2_GBITS) 124 newmode |= (value<<3) & set->bits; 125 if (set->cmd2 & CMD2_OBITS) 126 newmode |= value & set->bits; 127 } 128 break; 129 130 case '+': 131 newmode |= set->bits; 132 break; 133 134 case '-': 135 newmode &= ~set->bits; 136 break; 137 138 case 'X': 139 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH)) 140 newmode |= set->bits; 141 break; 142 143 case '\0': 144 default: 145#ifdef SETMODE_DEBUG 146 (void)printf("getmode:%04o -> %04o\n", omode, newmode); 147#endif 148 return (newmode); 149 } 150} 151 152#define ADDCMD(a, b, c, d) \ 153 if (set >= endset) { \ 154 BITCMD *newset; \ 155 setlen += SET_LEN_INCR; \ 156 newset = realloc(saveset, sizeof(BITCMD) * setlen); \ 157 if (newset == NULL) \ 158 goto out; \ 159 set = newset + (set - saveset); \ 160 saveset = newset; \ 161 endset = newset + (setlen - 2); \ 162 } \ 163 set = addcmd(set, (mode_t)(a), (mode_t)(b), (mode_t)(c), (d)) 164 165#define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO) 166 167void * 168setmode(const char *p) 169{ 170 int serrno; 171 char op, *ep; 172 BITCMD *set, *saveset, *endset; 173 sigset_t sigset, sigoset; 174 mode_t mask, perm, permXbits, who; 175 long perml; 176 int equalopdone; 177 int setlen; 178 179 if (!*p) { 180 errno = EINVAL; 181 return (NULL); 182 } 183 184 /* 185 * Get a copy of the mask for the permissions that are mask relative. 186 * Flip the bits, we want what's not set. Since it's possible that 187 * the caller is opening files inside a signal handler, protect them 188 * as best we can. 189 */ 190 sigfillset(&sigset); 191 (void)__libc_sigprocmask(SIG_BLOCK, &sigset, &sigoset); 192 (void)umask(mask = umask(0)); 193 mask = ~mask; 194 (void)__libc_sigprocmask(SIG_SETMASK, &sigoset, NULL); 195 196 setlen = SET_LEN + 2; 197 198 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL) 199 return (NULL); 200 saveset = set; 201 endset = set + (setlen - 2); 202 203 /* 204 * If an absolute number, get it and return; disallow non-octal digits 205 * or illegal bits. 206 */ 207 if (isdigit((unsigned char)*p)) { 208 errno = 0; 209 perml = strtol(p, &ep, 8); 210 if (*ep) { 211 errno = EINVAL; 212 goto out; 213 } 214 if (errno == ERANGE && (perml == LONG_MAX || perml == LONG_MIN)) 215 goto out; 216 if (perml & ~(STANDARD_BITS|S_ISTXT)) { 217 errno = EINVAL; 218 goto out; 219 } 220 perm = (mode_t)perml; 221 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask); 222 set->cmd = 0; 223 return (saveset); 224 } 225 226 /* 227 * Build list of structures to set/clear/copy bits as described by 228 * each clause of the symbolic mode. 229 */ 230 equalopdone = 0; 231 for (;;) { 232 /* First, find out which bits might be modified. */ 233 for (who = 0;; ++p) { 234 switch (*p) { 235 case 'a': 236 who |= STANDARD_BITS; 237 break; 238 case 'u': 239 who |= S_ISUID|S_IRWXU; 240 break; 241 case 'g': 242 who |= S_ISGID|S_IRWXG; 243 break; 244 case 'o': 245 who |= S_IRWXO; 246 break; 247 default: 248 goto getop; 249 } 250 } 251 252getop: if ((op = *p++) != '+' && op != '-' && op != '=') { 253 errno = EINVAL; 254 goto out; 255 } 256 if (op == '=') 257 equalopdone = 0; 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 || who & ~S_IRWXO) 268 perm |= S_ISUID|S_ISGID; 269 break; 270 case 't': 271 /* If only "other" bits ignore sticky. */ 272 if (!who || 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 == '=') 299 equalopdone = 1; 300 if (op == '+' && permXbits) { 301 ADDCMD('X', who, permXbits, mask); 302 permXbits = 0; 303 } 304 ADDCMD(*p, who, op, mask); 305 break; 306 307 default: 308 /* 309 * Add any permissions that we haven't already 310 * done. 311 */ 312 if (perm || (op == '=' && !equalopdone)) { 313 if (op == '=') 314 equalopdone = 1; 315 ADDCMD(op, who, perm, mask); 316 perm = 0; 317 } 318 if (permXbits) { 319 ADDCMD('X', who, permXbits, mask); 320 permXbits = 0; 321 } 322 goto apply; 323 } 324 } 325 326apply: if (!*p) 327 break; 328 if (*p != ',') 329 goto getop; 330 ++p; 331 } 332 set->cmd = 0; 333#ifdef SETMODE_DEBUG 334 (void)printf("Before compress_mode()\n"); 335 dumpmode(saveset); 336#endif 337 compress_mode(saveset); 338#ifdef SETMODE_DEBUG 339 (void)printf("After compress_mode()\n"); 340 dumpmode(saveset); 341#endif 342 return (saveset); 343out: 344 serrno = errno; 345 free(saveset); 346 errno = serrno; 347 return NULL; 348} 349 350static BITCMD * 351addcmd(BITCMD *set, mode_t op, mode_t who, mode_t oparg, mode_t mask) 352{ 353 switch (op) { 354 case '=': 355 set->cmd = '-'; 356 set->bits = who ? who : STANDARD_BITS; 357 set++; 358 359 op = '+'; 360 /* FALLTHROUGH */ 361 case '+': 362 case '-': 363 case 'X': 364 set->cmd = op; 365 set->bits = (who ? who : mask) & oparg; 366 break; 367 368 case 'u': 369 case 'g': 370 case 'o': 371 set->cmd = op; 372 if (who) { 373 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) | 374 ((who & S_IRGRP) ? CMD2_GBITS : 0) | 375 ((who & S_IROTH) ? CMD2_OBITS : 0); 376 set->bits = (mode_t)~0; 377 } else { 378 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS; 379 set->bits = mask; 380 } 381 382 if (oparg == '+') 383 set->cmd2 |= CMD2_SET; 384 else if (oparg == '-') 385 set->cmd2 |= CMD2_CLR; 386 else if (oparg == '=') 387 set->cmd2 |= CMD2_SET|CMD2_CLR; 388 break; 389 } 390 return (set + 1); 391} 392 393#ifdef SETMODE_DEBUG 394static void 395dumpmode(BITCMD *set) 396{ 397 for (; set->cmd; ++set) 398 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n", 399 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "", 400 set->cmd2 & CMD2_CLR ? " CLR" : "", 401 set->cmd2 & CMD2_SET ? " SET" : "", 402 set->cmd2 & CMD2_UBITS ? " UBITS" : "", 403 set->cmd2 & CMD2_GBITS ? " GBITS" : "", 404 set->cmd2 & CMD2_OBITS ? " OBITS" : ""); 405} 406#endif 407 408/* 409 * Given an array of bitcmd structures, compress by compacting consecutive 410 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u', 411 * 'g' and 'o' commands continue to be separate. They could probably be 412 * compacted, but it's not worth the effort. 413 */ 414static void 415compress_mode(BITCMD *set) 416{ 417 BITCMD *nset; 418 int setbits, clrbits, Xbits, op; 419 420 for (nset = set;;) { 421 /* Copy over any 'u', 'g' and 'o' commands. */ 422 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') { 423 *set++ = *nset++; 424 if (!op) 425 return; 426 } 427 428 for (setbits = clrbits = Xbits = 0;; nset++) { 429 if ((op = nset->cmd) == '-') { 430 clrbits |= nset->bits; 431 setbits &= ~nset->bits; 432 Xbits &= ~nset->bits; 433 } else if (op == '+') { 434 setbits |= nset->bits; 435 clrbits &= ~nset->bits; 436 Xbits &= ~nset->bits; 437 } else if (op == 'X') 438 Xbits |= nset->bits & ~setbits; 439 else 440 break; 441 } 442 if (clrbits) { 443 set->cmd = '-'; 444 set->cmd2 = 0; 445 set->bits = clrbits; 446 set++; 447 } 448 if (setbits) { 449 set->cmd = '+'; 450 set->cmd2 = 0; 451 set->bits = setbits; 452 set++; 453 } 454 if (Xbits) { 455 set->cmd = 'X'; 456 set->cmd2 = 0; 457 set->bits = Xbits; 458 set++; 459 } 460 } 461} 462