Add new setmode and getmode functions from FreeBSD

5 files changed, 573 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index f28a27c..74016bc 100644
--- a/Makefile
+++ b/Makefile
@@ -13,6 +13,7 @@ LIB_DIST := Makefile Versions libbsd.pc
 LIB_SRCS := arc4random.c bsd_getopt.c err.c fgetln.c heapsort.c \
 	    humanize_number.c inet_net_pton.c \
 	    hash/md5.c hash/md5hl.c \
+	    setmode.c \
 	    strlcat.c strlcpy.c fmtcheck.c progname.c vis.c unvis.c
 LIB_SRCS := $(patsubst %,src/%,$(LIB_SRCS))
 
@@ -23,7 +24,7 @@ LIB_GEN_SRCS := \
 LIB_INCLUDES := bsd/err.h bsd/getopt.h bsd/ip_icmp.h bsd/random.h bsd/queue.h bsd/md5.h bsd/string.h \
 		bsd/bsd.h bsd/cdefs.h bsd/stdlib.h vis.h libutil.h
 
-LIB_MANS := arc4random.3 strlcpy.3 fgetln.3 fmtcheck.3 md5.3
+LIB_MANS := arc4random.3 strlcpy.3 fgetln.3 fmtcheck.3 setmode.3 md5.3
 LIB_MANS := $(patsubst %,man/%,$(LIB_MANS))
 
 LIB_STATIC_OBJS = $(LIB_SRCS:%.c=%.o)
diff --git a/Versions b/Versions
index b4e8392..bb3e0a2 100644
--- a/Versions
+++ b/Versions
@@ -15,6 +15,10 @@ LIBBSD_0.0 {
     getprogname; setprogname;
     strlcpy;
     strlcat;
+
+    setmode;
+    getmode;
+
     vis; strvis; strvisx;
     unvis; strunvis; strunvisx;
     MD5Init;
diff --git a/include/bsd/stdlib.h b/include/bsd/stdlib.h
index f450e56..16376cb 100644
--- a/include/bsd/stdlib.h
+++ b/include/bsd/stdlib.h
@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 2005 Aurelien Jarno
  * Copyright (C) 2006 Robert Millan
+ * Copyright (C) 2008 Guillem Jover
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -28,6 +29,7 @@
 #ifndef LIBBSD_STDLIB_H
 #define LIBBSD_STDLIB_H
 
+#include <sys/stat.h>
 #include <stdlib.h>
 
 const char *fmtcheck (const char *, const char *);
@@ -37,4 +39,11 @@ void setprogname (char *);
 
 int heapsort (void *, size_t, size_t, int (*)(const void *, const void *));
 
+#ifndef S_ISTXT
+#define S_ISTXT S_ISVTX
+#endif
+
+mode_t getmode(const void *set, mode_t mode);
+void *setmode(const char *mode_str);
+
 #endif
diff --git a/man/setmode.3 b/man/setmode.3
new file mode 100644
index 0000000..94fd5d1
--- /dev/null
+++ b/man/setmode.3
@@ -0,0 +1,114 @@
+.\" Copyright (c) 1989, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" 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.
+.\"
+.\"     @(#)setmode.3	8.2 (Berkeley) 4/28/95
+.\" $FreeBSD: src/lib/libc/gen/setmode.3,v 1.12 2007/01/09 00:27:55 imp Exp $
+.\"
+.Dd April 28, 1995
+.Dt SETMODE 3
+.Os
+.Sh NAME
+.Nm getmode ,
+.Nm setmode
+.Nd modify mode bits
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In unistd.h
+.Ft mode_t
+.Fn getmode "const void *set" "mode_t mode"
+.Ft void *
+.Fn setmode "const char *mode_str"
+.Sh DESCRIPTION
+The
+.Fn getmode
+function
+returns a copy of the file permission bits
+.Fa mode
+as altered by the values pointed to by
+.Fa set .
+While only the mode bits are altered, other parts of the file mode
+may be examined.
+.Pp
+The
+.Fn setmode
+function
+takes an absolute (octal) or symbolic value, as described in
+.Xr chmod 1 ,
+as an argument
+and returns a pointer to mode values to be supplied to
+.Fn getmode .
+Because some of the symbolic values are relative to the file
+creation mask,
+.Fn setmode
+may call
+.Xr umask 2 .
+If this occurs, the file creation mask will be restored before
+.Fn setmode
+returns.
+If the calling program changes the value of its file creation mask
+after calling
+.Fn setmode ,
+.Fn setmode
+must be called again if
+.Fn getmode
+is to modify future file modes correctly.
+.Pp
+If the mode passed to
+.Fn setmode
+is invalid or if memory cannot be allocated for the return value,
+.Fn setmode
+returns
+.Dv NULL .
+.Pp
+The value returned from
+.Fn setmode
+is obtained from
+.Fn malloc
+and should be returned to the system with
+.Fn free
+when the program is done with it, generally after a call to
+.Fn getmode .
+.Sh ERRORS
+The
+.Fn setmode
+function
+may fail and set errno for any of the errors specified for the library
+routine
+.Xr malloc 3 .
+.Sh SEE ALSO
+.Xr chmod 1 ,
+.Xr stat 2 ,
+.Xr umask 2 ,
+.Xr malloc 3
+.Sh HISTORY
+The
+.Fn getmode
+and
+.Fn setmode
+functions first appeared in
+.Bx 4.4 .
diff --git a/src/setmode.c b/src/setmode.c
new file mode 100644
index 0000000..66f2924
--- /dev/null
+++ b/src/setmode.c
@@ -0,0 +1,444 @@
+/*
+ * 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++;
+		}
+	}
+}