source: vendor/FreeBSD-libc/current/gen/setmode.c

Last change on this file was 2219, checked in by (none), 20 years ago

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Line 
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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94";
39#endif /* LIBC_SCCS and not lint */
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: src/lib/libc/gen/setmode.c,v 1.10 2005/04/08 21:15:38 stefanf Exp $");
42
43#include "namespace.h"
44#include <sys/types.h>
45#include <sys/stat.h>
46
47#include <ctype.h>
48#include <signal.h>
49#include <stddef.h>
50#include <stdlib.h>
51#include <unistd.h>
52
53#ifdef SETMODE_DEBUG
54#include <stdio.h>
55#endif
56#include "un-namespace.h"
57
58#define SET_LEN 6 /* initial # of bitcmd struct to malloc */
59#define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */
60
61typedef struct bitcmd {
62 char cmd;
63 char cmd2;
64 mode_t bits;
65} BITCMD;
66
67#define CMD2_CLR 0x01
68#define CMD2_SET 0x02
69#define CMD2_GBITS 0x04
70#define CMD2_OBITS 0x08
71#define CMD2_UBITS 0x10
72
73static BITCMD *addcmd(BITCMD *, int, int, int, u_int);
74static void compress_mode(BITCMD *);
75#ifdef SETMODE_DEBUG
76static void dumpmode(BITCMD *);
77#endif
78
79/*
80 * Given the old mode and an array of bitcmd structures, apply the operations
81 * described in the bitcmd structures to the old mode, and return the new mode.
82 * Note that there is no '=' command; a strict assignment is just a '-' (clear
83 * bits) followed by a '+' (set bits).
84 */
85mode_t
86getmode(const void *bbox, mode_t omode)
87{
88 const BITCMD *set;
89 mode_t clrval, newmode, value;
90
91 set = (const BITCMD *)bbox;
92 newmode = omode;
93 for (value = 0;; set++)
94 switch(set->cmd) {
95 /*
96 * When copying the user, group or other bits around, we "know"
97 * where the bits are in the mode so that we can do shifts to
98 * copy them around. If we don't use shifts, it gets real
99 * grundgy with lots of single bit checks and bit sets.
100 */
101 case 'u':
102 value = (newmode & S_IRWXU) >> 6;
103 goto common;
104
105 case 'g':
106 value = (newmode & S_IRWXG) >> 3;
107 goto common;
108
109 case 'o':
110 value = newmode & S_IRWXO;
111common: if (set->cmd2 & CMD2_CLR) {
112 clrval =
113 (set->cmd2 & CMD2_SET) ? S_IRWXO : value;
114 if (set->cmd2 & CMD2_UBITS)
115 newmode &= ~((clrval<<6) & set->bits);
116 if (set->cmd2 & CMD2_GBITS)
117 newmode &= ~((clrval<<3) & set->bits);
118 if (set->cmd2 & CMD2_OBITS)
119 newmode &= ~(clrval & set->bits);
120 }
121 if (set->cmd2 & CMD2_SET) {
122 if (set->cmd2 & CMD2_UBITS)
123 newmode |= (value<<6) & set->bits;
124 if (set->cmd2 & CMD2_GBITS)
125 newmode |= (value<<3) & set->bits;
126 if (set->cmd2 & CMD2_OBITS)
127 newmode |= value & set->bits;
128 }
129 break;
130
131 case '+':
132 newmode |= set->bits;
133 break;
134
135 case '-':
136 newmode &= ~set->bits;
137 break;
138
139 case 'X':
140 if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
141 newmode |= set->bits;
142 break;
143
144 case '\0':
145 default:
146#ifdef SETMODE_DEBUG
147 (void)printf("getmode:%04o -> %04o\n", omode, newmode);
148#endif
149 return (newmode);
150 }
151}
152
153#define ADDCMD(a, b, c, d) \
154 if (set >= endset) { \
155 BITCMD *newset; \
156 setlen += SET_LEN_INCR; \
157 newset = realloc(saveset, sizeof(BITCMD) * setlen); \
158 if (!newset) { \
159 if (saveset) \
160 free(saveset); \
161 saveset = NULL; \
162 return (NULL); \
163 } \
164 set = newset + (set - saveset); \
165 saveset = newset; \
166 endset = newset + (setlen - 2); \
167 } \
168 set = addcmd(set, (a), (b), (c), (d))
169
170#define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
171
172void *
173setmode(const char *p)
174{
175 int perm, who;
176 char op, *ep;
177 BITCMD *set, *saveset, *endset;
178 sigset_t sigset, sigoset;
179 mode_t mask;
180 int equalopdone=0, permXbits, setlen;
181 long perml;
182
183 if (!*p)
184 return (NULL);
185
186 /*
187 * Get a copy of the mask for the permissions that are mask relative.
188 * Flip the bits, we want what's not set. Since it's possible that
189 * the caller is opening files inside a signal handler, protect them
190 * as best we can.
191 */
192 sigfillset(&sigset);
193 (void)_sigprocmask(SIG_BLOCK, &sigset, &sigoset);
194 (void)umask(mask = umask(0));
195 mask = ~mask;
196 (void)_sigprocmask(SIG_SETMASK, &sigoset, NULL);
197
198 setlen = SET_LEN + 2;
199
200 if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL)
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((unsigned char)*p)) {
210 perml = strtol(p, &ep, 8);
211 if (*ep || perml < 0 || perml & ~(STANDARD_BITS|S_ISTXT)) {
212 free(saveset);
213 return (NULL);
214 }
215 perm = (mode_t)perml;
216 ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
217 set->cmd = 0;
218 return (saveset);
219 }
220
221 /*
222 * Build list of structures to set/clear/copy bits as described by
223 * each clause of the symbolic mode.
224 */
225 for (;;) {
226 /* First, find out which bits might be modified. */
227 for (who = 0;; ++p) {
228 switch (*p) {
229 case 'a':
230 who |= STANDARD_BITS;
231 break;
232 case 'u':
233 who |= S_ISUID|S_IRWXU;
234 break;
235 case 'g':
236 who |= S_ISGID|S_IRWXG;
237 break;
238 case 'o':
239 who |= S_IRWXO;
240 break;
241 default:
242 goto getop;
243 }
244 }
245
246getop: if ((op = *p++) != '+' && op != '-' && op != '=') {
247 free(saveset);
248 return (NULL);
249 }
250 if (op == '=')
251 equalopdone = 0;
252
253 who &= ~S_ISTXT;
254 for (perm = 0, permXbits = 0;; ++p) {
255 switch (*p) {
256 case 'r':
257 perm |= S_IRUSR|S_IRGRP|S_IROTH;
258 break;
259 case 's':
260 /* If only "other" bits ignore set-id. */
261 if (!who || who & ~S_IRWXO)
262 perm |= S_ISUID|S_ISGID;
263 break;
264 case 't':
265 /* If only "other" bits ignore sticky. */
266 if (!who || who & ~S_IRWXO) {
267 who |= S_ISTXT;
268 perm |= S_ISTXT;
269 }
270 break;
271 case 'w':
272 perm |= S_IWUSR|S_IWGRP|S_IWOTH;
273 break;
274 case 'X':
275 permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
276 break;
277 case 'x':
278 perm |= S_IXUSR|S_IXGRP|S_IXOTH;
279 break;
280 case 'u':
281 case 'g':
282 case 'o':
283 /*
284 * When ever we hit 'u', 'g', or 'o', we have
285 * to flush out any partial mode that we have,
286 * and then do the copying of the mode bits.
287 */
288 if (perm) {
289 ADDCMD(op, who, perm, mask);
290 perm = 0;
291 }
292 if (op == '=')
293 equalopdone = 1;
294 if (op == '+' && permXbits) {
295 ADDCMD('X', who, permXbits, mask);
296 permXbits = 0;
297 }
298 ADDCMD(*p, who, op, mask);
299 break;
300
301 default:
302 /*
303 * Add any permissions that we haven't already
304 * done.
305 */
306 if (perm || (op == '=' && !equalopdone)) {
307 if (op == '=')
308 equalopdone = 1;
309 ADDCMD(op, who, perm, mask);
310 perm = 0;
311 }
312 if (permXbits) {
313 ADDCMD('X', who, permXbits, mask);
314 permXbits = 0;
315 }
316 goto apply;
317 }
318 }
319
320apply: if (!*p)
321 break;
322 if (*p != ',')
323 goto getop;
324 ++p;
325 }
326 set->cmd = 0;
327#ifdef SETMODE_DEBUG
328 (void)printf("Before compress_mode()\n");
329 dumpmode(saveset);
330#endif
331 compress_mode(saveset);
332#ifdef SETMODE_DEBUG
333 (void)printf("After compress_mode()\n");
334 dumpmode(saveset);
335#endif
336 return (saveset);
337}
338
339static BITCMD *
340addcmd(BITCMD *set, int op, int who, int oparg, u_int mask)
341{
342 switch (op) {
343 case '=':
344 set->cmd = '-';
345 set->bits = who ? who : STANDARD_BITS;
346 set++;
347
348 op = '+';
349 /* FALLTHROUGH */
350 case '+':
351 case '-':
352 case 'X':
353 set->cmd = op;
354 set->bits = (who ? who : mask) & oparg;
355 break;
356
357 case 'u':
358 case 'g':
359 case 'o':
360 set->cmd = op;
361 if (who) {
362 set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
363 ((who & S_IRGRP) ? CMD2_GBITS : 0) |
364 ((who & S_IROTH) ? CMD2_OBITS : 0);
365 set->bits = (mode_t)~0;
366 } else {
367 set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
368 set->bits = mask;
369 }
370
371 if (oparg == '+')
372 set->cmd2 |= CMD2_SET;
373 else if (oparg == '-')
374 set->cmd2 |= CMD2_CLR;
375 else if (oparg == '=')
376 set->cmd2 |= CMD2_SET|CMD2_CLR;
377 break;
378 }
379 return (set + 1);
380}
381
382#ifdef SETMODE_DEBUG
383static void
384dumpmode(BITCMD *set)
385{
386 for (; set->cmd; ++set)
387 (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
388 set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
389 set->cmd2 & CMD2_CLR ? " CLR" : "",
390 set->cmd2 & CMD2_SET ? " SET" : "",
391 set->cmd2 & CMD2_UBITS ? " UBITS" : "",
392 set->cmd2 & CMD2_GBITS ? " GBITS" : "",
393 set->cmd2 & CMD2_OBITS ? " OBITS" : "");
394}
395#endif
396
397/*
398 * Given an array of bitcmd structures, compress by compacting consecutive
399 * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u',
400 * 'g' and 'o' commands continue to be separate. They could probably be
401 * compacted, but it's not worth the effort.
402 */
403static void
404compress_mode(BITCMD *set)
405{
406 BITCMD *nset;
407 int setbits, clrbits, Xbits, op;
408
409 for (nset = set;;) {
410 /* Copy over any 'u', 'g' and 'o' commands. */
411 while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
412 *set++ = *nset++;
413 if (!op)
414 return;
415 }
416
417 for (setbits = clrbits = Xbits = 0;; nset++) {
418 if ((op = nset->cmd) == '-') {
419 clrbits |= nset->bits;
420 setbits &= ~nset->bits;
421 Xbits &= ~nset->bits;
422 } else if (op == '+') {
423 setbits |= nset->bits;
424 clrbits &= ~nset->bits;
425 Xbits &= ~nset->bits;
426 } else if (op == 'X')
427 Xbits |= nset->bits & ~setbits;
428 else
429 break;
430 }
431 if (clrbits) {
432 set->cmd = '-';
433 set->cmd2 = 0;
434 set->bits = clrbits;
435 set++;
436 }
437 if (setbits) {
438 set->cmd = '+';
439 set->cmd2 = 0;
440 set->bits = setbits;
441 set++;
442 }
443 if (Xbits) {
444 set->cmd = 'X';
445 set->cmd2 = 0;
446 set->bits = Xbits;
447 set++;
448 }
449 }
450}
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