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- /* $OpenBSD: setmode.c,v 1.17 2005/08/08 08:05:34 espie Exp $ */
- /* $NetBSD: setmode.c,v 1.15 1997/02/07 22:21:06 christos Exp $ */
- /*
- * Copyright (c) 1989, 1993, 1994
- * The Regents of the University of California. All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Dave Borman at Cray Research, Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <ctype.h>
- #include <errno.h>
- #include <signal.h>
- #include <stdint.h>
- #include <stdlib.h>
- #include <unistd.h>
- #ifdef SETMODE_DEBUG
- #include <stdio.h>
- #endif
- __SCCSID("@(#)setmode.c 8.2 (Berkeley) 3/25/94");
- __RCSID("$MirOS: src/lib/libc/gen/setmode.c,v 1.15 2010/10/08 17:57:00 tg Exp $");
- #define SET_LEN 6 /* initial # of bitcmd struct to malloc */
- #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */
- #if !defined(S_ISTXT) && defined(S_ISVTX)
- #define S_ISTXT S_ISVTX
- #endif
- typedef struct bitcmd {
- mode_t bits;
- char cmd;
- char cmd2;
- } BITCMD;
- #define CMD2_CLR 0x01
- #define CMD2_SET 0x02
- #define CMD2_GBITS 0x04
- #define CMD2_OBITS 0x08
- #define CMD2_UBITS 0x10
- static BITCMD *addcmd(BITCMD *, int, int, int, u_int);
- static void compress_mode(BITCMD *);
- #ifdef SETMODE_DEBUG
- static void dumpmode(BITCMD *);
- #endif
- /*
- * Given the old mode and an array of bitcmd structures, apply the operations
- * described in the bitcmd structures to the old mode, and return the new mode.
- * Note that there is no '=' command; a strict assignment is just a '-' (clear
- * bits) followed by a '+' (set bits).
- */
- mode_t
- getmode(const void *bbox, mode_t omode)
- {
- const BITCMD *set;
- mode_t clrval, newmode, value;
- set = (const BITCMD *)bbox;
- newmode = omode;
- for (value = 0;; set++)
- switch(set->cmd) {
- /*
- * When copying the user, group or other bits around, we "know"
- * where the bits are in the mode so that we can do shifts to
- * copy them around. If we don't use shifts, it gets real
- * grundgy with lots of single bit checks and bit sets.
- */
- case 'u':
- value = (newmode & S_IRWXU) >> 6;
- goto common;
- case 'g':
- value = (newmode & S_IRWXG) >> 3;
- goto common;
- case 'o':
- value = newmode & S_IRWXO;
- common:
- if (set->cmd2 & CMD2_CLR) {
- clrval =
- (set->cmd2 & CMD2_SET) ? S_IRWXO : value;
- if (set->cmd2 & CMD2_UBITS)
- newmode &= ~((clrval<<6) & set->bits);
- if (set->cmd2 & CMD2_GBITS)
- newmode &= ~((clrval<<3) & set->bits);
- if (set->cmd2 & CMD2_OBITS)
- newmode &= ~(clrval & set->bits);
- }
- if (set->cmd2 & CMD2_SET) {
- if (set->cmd2 & CMD2_UBITS)
- newmode |= (value<<6) & set->bits;
- if (set->cmd2 & CMD2_GBITS)
- newmode |= (value<<3) & set->bits;
- if (set->cmd2 & CMD2_OBITS)
- newmode |= value & set->bits;
- }
- break;
- case '+':
- newmode |= set->bits;
- break;
- case '-':
- newmode &= ~set->bits;
- break;
- case 'X':
- if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
- newmode |= set->bits;
- break;
- case '\0':
- default:
- #ifdef SETMODE_DEBUG
- (void)printf("getmode:%04o -> %04o\n", omode, newmode);
- #endif
- return (newmode);
- }
- }
- #define notoktomul(a, b) ((a) && (b) && (SIZE_MAX / (a) < (b)))
- #define ADDCMD(a, b, c, d) \
- if (set >= endset) { \
- BITCMD *newset; \
- setlen += SET_LEN_INCR; \
- if (notoktomul(setlen, sizeof(BITCMD)) || \
- (newset = realloc(saveset, setlen * \
- sizeof(BITCMD))) == NULL) { \
- free(saveset); \
- return (NULL); \
- } \
- set = newset + (set - saveset); \
- saveset = newset; \
- endset = newset + (setlen - 2); \
- } \
- set = addcmd(set, (a), (b), (c), (d))
- #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
- void *
- setmode(const char *p)
- {
- int perm, who;
- char op, *ep;
- BITCMD *set, *saveset, *endset;
- sigset_t signset, sigoset;
- mode_t mask;
- int equalopdone = 0, permXbits, setlen;
- u_long perml;
- if (!*p)
- return (NULL);
- /*
- * Get a copy of the mask for the permissions that are mask relative.
- * Flip the bits, we want what's not set. Since it's possible that
- * the caller is opening files inside a signal handler, protect them
- * as best we can.
- */
- sigfillset(&signset);
- (void)sigprocmask(SIG_BLOCK, &signset, &sigoset);
- (void)umask(mask = umask(0));
- mask = ~mask;
- (void)sigprocmask(SIG_SETMASK, &sigoset, NULL);
- setlen = SET_LEN + 2;
-
- if (notoktomul(setlen, sizeof(BITCMD)) ||
- (set = malloc(setlen * sizeof(BITCMD))) == NULL)
- return (NULL);
- saveset = set;
- endset = set + (setlen - 2);
- /*
- * If an absolute number, get it and return; disallow non-octal digits
- * or illegal bits.
- */
- if (isdigit((unsigned char)*p)) {
- perml = strtoul(p, &ep, 8);
- /* The test on perml will also catch overflow. */
- if (*ep != '\0' || (perml & ~(STANDARD_BITS|S_ISTXT))) {
- free(saveset);
- errno = ERANGE;
- return (NULL);
- }
- perm = (mode_t)perml;
- ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
- set->cmd = 0;
- return (saveset);
- }
- /*
- * Build list of structures to set/clear/copy bits as described by
- * each clause of the symbolic mode.
- */
- for (;;) {
- /* First, find out which bits might be modified. */
- for (who = 0;; ++p) {
- switch (*p) {
- case 'a':
- who |= STANDARD_BITS;
- break;
- case 'u':
- who |= S_ISUID|S_IRWXU;
- break;
- case 'g':
- who |= S_ISGID|S_IRWXG;
- break;
- case 'o':
- who |= S_IRWXO;
- break;
- default:
- goto getop;
- }
- }
- getop:
- if ((op = *p++) != '+' && op != '-' && op != '=') {
- free(saveset);
- return (NULL);
- }
- if (op == '=')
- equalopdone = 0;
- who &= ~S_ISTXT;
- for (perm = 0, permXbits = 0;; ++p) {
- switch (*p) {
- case 'r':
- perm |= S_IRUSR|S_IRGRP|S_IROTH;
- break;
- case 's':
- /*
- * If specific bits where requested and
- * only "other" bits ignore set-id.
- */
- if (who == 0 || (who & ~S_IRWXO))
- perm |= S_ISUID|S_ISGID;
- break;
- case 't':
- /*
- * If specific bits where requested and
- * only "other" bits ignore sticky.
- */
- if (who == 0 || (who & ~S_IRWXO)) {
- who |= S_ISTXT;
- perm |= S_ISTXT;
- }
- break;
- case 'w':
- perm |= S_IWUSR|S_IWGRP|S_IWOTH;
- break;
- case 'X':
- permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
- break;
- case 'x':
- perm |= S_IXUSR|S_IXGRP|S_IXOTH;
- break;
- case 'u':
- case 'g':
- case 'o':
- /*
- * When ever we hit 'u', 'g', or 'o', we have
- * to flush out any partial mode that we have,
- * and then do the copying of the mode bits.
- */
- if (perm) {
- ADDCMD(op, who, perm, mask);
- perm = 0;
- }
- if (op == '=')
- equalopdone = 1;
- if (op == '+' && permXbits) {
- ADDCMD('X', who, permXbits, mask);
- permXbits = 0;
- }
- ADDCMD(*p, who, op, mask);
- break;
- default:
- /*
- * Add any permissions that we haven't already
- * done.
- */
- if (perm || (op == '=' && !equalopdone)) {
- if (op == '=')
- equalopdone = 1;
- ADDCMD(op, who, perm, mask);
- perm = 0;
- }
- if (permXbits) {
- ADDCMD('X', who, permXbits, mask);
- permXbits = 0;
- }
- goto apply;
- }
- }
- apply:
- if (!*p)
- break;
- if (*p != ',')
- goto getop;
- ++p;
- }
- set->cmd = 0;
- #ifdef SETMODE_DEBUG
- (void)printf("Before compress_mode()\n");
- dumpmode(saveset);
- #endif
- compress_mode(saveset);
- #ifdef SETMODE_DEBUG
- (void)printf("After compress_mode()\n");
- dumpmode(saveset);
- #endif
- return (saveset);
- }
- static BITCMD *
- addcmd(BITCMD *set, int op, int who, int oparg, u_int mask)
- {
- switch (op) {
- case '=':
- set->cmd = '-';
- set->bits = who ? who : STANDARD_BITS;
- set++;
- op = '+';
- /* FALLTHROUGH */
- case '+':
- case '-':
- case 'X':
- set->cmd = op;
- set->bits = (who ? who : (int)mask) & oparg;
- break;
- case 'u':
- case 'g':
- case 'o':
- set->cmd = op;
- if (who) {
- set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
- ((who & S_IRGRP) ? CMD2_GBITS : 0) |
- ((who & S_IROTH) ? CMD2_OBITS : 0);
- set->bits = (mode_t)~0;
- } else {
- set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
- set->bits = mask;
- }
-
- if (oparg == '+')
- set->cmd2 |= CMD2_SET;
- else if (oparg == '-')
- set->cmd2 |= CMD2_CLR;
- else if (oparg == '=')
- set->cmd2 |= CMD2_SET|CMD2_CLR;
- break;
- }
- return (set + 1);
- }
- #ifdef SETMODE_DEBUG
- static void
- dumpmode(BITCMD *set)
- {
- for (; set->cmd; ++set)
- (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
- set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
- set->cmd2 & CMD2_CLR ? " CLR" : "",
- set->cmd2 & CMD2_SET ? " SET" : "",
- set->cmd2 & CMD2_UBITS ? " UBITS" : "",
- set->cmd2 & CMD2_GBITS ? " GBITS" : "",
- set->cmd2 & CMD2_OBITS ? " OBITS" : "");
- }
- #endif
- /*
- * Given an array of bitcmd structures, compress by compacting consecutive
- * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u',
- * 'g' and 'o' commands continue to be separate. They could probably be
- * compacted, but it's not worth the effort.
- */
- static void
- compress_mode(BITCMD *set)
- {
- BITCMD *nset;
- int setbits, clrbits, Xbits, op;
- for (nset = set;;) {
- /* Copy over any 'u', 'g' and 'o' commands. */
- while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
- *set++ = *nset++;
- if (!op)
- return;
- }
- for (setbits = clrbits = Xbits = 0;; nset++) {
- if ((op = nset->cmd) == '-') {
- clrbits |= nset->bits;
- setbits &= ~nset->bits;
- Xbits &= ~nset->bits;
- } else if (op == '+') {
- setbits |= nset->bits;
- clrbits &= ~nset->bits;
- Xbits &= ~nset->bits;
- } else if (op == 'X')
- Xbits |= nset->bits & ~setbits;
- else
- break;
- }
- if (clrbits) {
- set->cmd = '-';
- set->cmd2 = 0;
- set->bits = clrbits;
- set++;
- }
- if (setbits) {
- set->cmd = '+';
- set->cmd2 = 0;
- set->bits = setbits;
- set++;
- }
- if (Xbits) {
- set->cmd = 'X';
- set->cmd2 = 0;
- set->bits = Xbits;
- set++;
- }
- }
- }
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