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BSD 4_4 release
[unix-history] / usr / src / lib / libc / gen / setmode.c
/*
* Copyright (c) 1989, 1993
* 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 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <errno.h>
#include <stddef.h>
#ifdef SETMODE_DEBUG
#include <stdio.h>
#endif
#include <stdlib.h>
#include <ctype.h>
#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 __P((BITCMD *, int, int, int, u_int));
static int compress_mode __P((BITCMD *));
#ifdef SETMODE_DEBUG
static 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_t
getmode(bbox, omode)
void *bbox;
mode_t omode;
{
register BITCMD *set;
register mode_t 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) {
if (set->cmd2 & CMD2_UBITS)
newmode &= ~(S_IRWXU & set->bits);
if (set->cmd2 & CMD2_GBITS)
newmode &= ~(S_IRWXG & set->bits);
if (set->cmd2 & CMD2_OBITS)
newmode &= ~(S_IRWXO & 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 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, (char **)0, 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);
}
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 || op == '=') {
ADDCMD(op, who, perm, mask);
perm = 0;
}
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 == '=') {
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 '+':
case 'X':
set->cmd = op;
set->bits = (who ? who : mask) & oparg;
break;
case '-':
set->cmd = '-';
set->bits = (who ? who : (S_IRWXU|S_IRWXG|S_IRWXO)) & oparg;
break;
case '=':
set->cmd = '-';
if (!who) {
set->bits = STANDARD_BITS;
who = mask;
} else
set->bits = who;
set++;
set->cmd = '+';
set->bits = who & 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_DEBUG
static void
dumpmode(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 int
compress_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++;
}
}
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.