/* * 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. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *	This product includes software developed by the University of *	California, Berkeley and its contributors. * 4. 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. */#if defined(LIBC_SCCS) && !defined(lint)static char sccsid[] = "@(#)setmode.c	8.2 (Berkeley) 3/25/94";#endif /* LIBC_SCCS and not lint */#include <sys/types.h>#include <sys/stat.h>#include <ctype.h>#include <errno.h>#include <signal.h>#include <stddef.h>#include <stdlib.h>#ifdef SETMODE_DEBUG#include <stdio.h>#endif#define	SET_LEN	6		/* initial # of bitcmd struct to malloc */#define	SET_LEN_INCR 4		/* # of bitcmd structs to add as needed */typedef struct bitcmd {	char	cmd;	char	cmd2;	mode_t	bits;} BITCMD;#define	CMD2_CLR	0x01#define	CMD2_SET	0x02#define	CMD2_GBITS	0x04#define	CMD2_OBITS	0x08#define	CMD2_UBITS	0x10static BITCMD	*addcmd __P((BITCMD *, int, int, int, u_int));static int	 compress_mode __P((BITCMD *));#ifdef SETMODE_DEBUGstatic void	 dumpmode __P((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_tgetmode(bbox, omode)	void *bbox;	mode_t omode;{	register BITCMD *set;	register mode_t clrval, newmode, value;	set = (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	ADDCMD(a, b, c, d)						\	if (set >= endset) {						\		register BITCMD *newset;				\		setlen += SET_LEN_INCR;					\		newset = realloc(saveset, sizeof(BITCMD) * setlen);	\		if (!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(p)	register char *p;{	register int perm, who;	register char op;	BITCMD *set, *saveset, *endset;	sigset_t sigset, sigoset;	mode_t mask;	int equalopdone, permXbits, setlen;	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(&sigset);        (void)sigprocmask(SIG_BLOCK, &sigset, &sigoset);	(void)umask(mask = umask(0));	mask = ~mask;        (void)sigprocmask(SIG_SETMASK, &sigoset, NULL);	setlen = SET_LEN + 2;		if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == 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(*p)) {		perm = (mode_t)strtol(p, NULL, 8);		if (perm & ~(STANDARD_BITS|S_ISTXT)) {			free(saveset);			return (NULL);		}		while (*++p)			if (*p < '0' || *p > '7') {				free(saveset);				return (NULL);			}		ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);		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 only "other" bits ignore set-id. */				if (who & ~S_IRWXO)					perm |= S_ISUID|S_ISGID;				break;			case 't':				/* If only "other" bits ignore sticky. */				if (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(set, op, who, oparg, mask)	BITCMD *set;	register int oparg, who;	register int op;	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 : 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 = ~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_DEBUGstatic voiddumpmode(set)	register 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 intcompress_mode(set)	register BITCMD *set;{	register BITCMD *nset;	register 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++;		}	}}