kc3-lang/libbsd/src/setmode.c

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• Hash : 38829bdc
  Author :
  Date : 2008-07-09T09:07:03
  

  Add new setmode and getmode functions from FreeBSD

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• src/setmode.c

• /*
   * 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.
   * 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/cdefs.h>
  __FBSDID("$FreeBSD: src/lib/libc/gen/setmode.c,v 1.11 2007/01/09 00:27:55 imp Exp $");
  
  #include <sys/types.h>
  #include <sys/stat.h>
  
  #include <ctype.h>
  #include <signal.h>
  #include <stddef.h>
  #include <stdlib.h>
  #include <unistd.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	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	ADDCMD(a, b, c, d)						\
  	if (set >= endset) {						\
  		BITCMD *newset;						\
  		setlen += SET_LEN_INCR;					\
  		newset = realloc(saveset, sizeof(BITCMD) * setlen);	\
  		if (!newset) {						\
  			if (saveset)					\
  				free(saveset);				\
  			saveset = NULL;					\
  			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 sigset, sigoset;
  	mode_t mask;
  	int equalopdone=0, permXbits, setlen;
  	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(&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((unsigned char)*p)) {
  		perml = strtol(p, &ep, 8);
  		if (*ep || perml < 0 || perml & ~(STANDARD_BITS|S_ISTXT)) {
  			free(saveset);
  			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 only "other" bits ignore set-id. */
  				if (!who || who & ~S_IRWXO)
  					perm |= S_ISUID|S_ISGID;
  				break;
  			case 't':
  				/* If only "other" bits ignore sticky. */
  				if (!who || 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 : 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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