OpenSolaris_b135/cmd/chmod/common.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* Portions of this source code were derived from Berkeley 4.3 BSD
* under license from the Regents of the University of California.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Use of this object by a utility (so far chmod, mkdir and mkfifo use
* it) requires that the utility implement an error-processing routine
* named errmsg(), with a prototype as specified below.
*
* This is necessary because the mode-parsing code here makes use of such
* a routine, located in chmod.c. The error-reporting style of the
* utilities sharing this code differs enough that it is difficult to
* implement a common version of this routine to be used by all.
*/
/*
* Note that many convolutions are necessary
* due to the re-use of bits between locking
* and setgid
*/
#include <ctype.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <locale.h>
#include <string.h> /* strerror() */
#include <stdarg.h>
#define USER 05700 /* user's bits */
#define GROUP 02070 /* group's bits */
#define OTHER 00007 /* other's bits */
#define ALL 07777 /* all */
#define READ 00444 /* read permit */
#define WRITE 00222 /* write permit */
#define EXEC 00111 /* exec permit */
#define SETID 06000 /* set[ug]id */
#define LOCK 02000 /* lock permit */
#define STICKY 01000 /* sticky bit */
#define GROUP_RWX (GROUP & (READ | WRITE | EXEC))
#define WHO_EMPTY 0
static char *msp;
extern void
errmsg(int severity, int code, char *format, ...);
static int
what(void);
static mode_t
abs(mode_t mode, o_mode_t *group_clear_bits, o_mode_t *group_set_bits),
who(void);
mode_t
newmode_common(char *ms, mode_t new_mode, mode_t umsk, char *file, char *path,
o_mode_t *group_clear_bits, o_mode_t *group_set_bits);
/*
* Wrapper for newmode_common. This function is called by mkdir and
* mkfifo.
*/
mode_t
newmode(char *ms, mode_t new_mode, mode_t umsk, char *file, char *path)
{
o_mode_t tmp1, tmp2;
return (newmode_common(ms, new_mode, umsk, file, path, &tmp1, &tmp2));
}
/*
* We are parsing a comma-separated list of mode expressions of the form:
*
* [<who>] <op> [<perms>]
*/
/* ARGSUSED */
mode_t
newmode_common(char *ms, mode_t new_mode, mode_t umsk, char *file, char *path,
o_mode_t *group_clear_bits, o_mode_t *group_set_bits)
{
/*
* new_mode contains the mode value constructed by parsing the
* expression pointed to by ms
* old_mode contains the mode provided by the caller
* oper contains +|-|= information
* perms_msk contains rwx(slt) information
* umsk contains the umask value to be assumed.
* who_empty is non-zero if the <who> clause did not appear.
* who_msk contains USER|GROUP|OTHER information
*/
int oper; /* <op> */
int lcheck;
int scheck;
int xcheck;
int goon;
int operand_empty = 0;
int who_empty;
mode_t who_msk;
mode_t perms_msk;
mode_t old_mode = new_mode; /* save original mode */
mode_t grp_change;
msp = ms;
*group_clear_bits = 0;
*group_set_bits = 0;
if (isdigit(*msp))
return (abs(old_mode, group_clear_bits, group_set_bits));
do {
/*
* When <who> is empty, and <oper> == `=`, the umask is
* obeyed. So we need to make note of it here, for use
* later.
*/
if ((who_msk = who()) == WHO_EMPTY) {
who_empty = 1;
who_msk = ALL;
} else {
who_empty = 0;
}
while (oper = what()) {
/*
* this section processes permissions
*/
operand_empty++;
perms_msk = 0;
goon = 0;
lcheck = scheck = xcheck = 0;
switch (*msp) {
case 'u':
perms_msk = (new_mode & USER) >> 6;
goto dup;
case 'g':
perms_msk = (new_mode & GROUP) >> 3;
goto dup;
case 'o':
perms_msk = (new_mode & OTHER);
dup:
perms_msk &= (READ|WRITE|EXEC);
perms_msk |= (perms_msk << 3) |
(perms_msk << 6);
msp++;
goon = 1;
}
while (goon == 0) {
switch (*msp++) {
case 'r':
perms_msk |= READ;
continue;
case 'w':
perms_msk |= WRITE;
continue;
case 'x':
perms_msk |= EXEC;
xcheck = 1;
continue;
case 'X':
if (((old_mode & S_IFMT) == S_IFDIR) ||
(old_mode & EXEC)) {
perms_msk |= EXEC;
xcheck = 1;
}
continue;
case 'l':
perms_msk |= LOCK;
who_msk |= LOCK;
lcheck = 1;
continue;
case 's':
perms_msk |= SETID;
scheck = 1;
continue;
case 't':
perms_msk |= STICKY;
continue;
default:
msp--;
goon = 1;
}
}
perms_msk &= who_msk;
switch (oper) {
case '+':
if (who_empty) {
perms_msk &= ~umsk;
}
/* is group execution requested? */
if (xcheck == 1 &&
(perms_msk & GROUP & EXEC) ==
(GROUP & EXEC)) {
/* not locking, too! */
if (lcheck == 1 && !S_ISDIR(new_mode)) {
errmsg(1, 3,
gettext("Group execution "
"and locking not permitted "
"together\n"));
}
/*
* not if the file is already
* lockable.
*/
if (((new_mode & GROUP &
(LOCK | EXEC)) == LOCK) &&
!S_ISDIR(new_mode)) {
errmsg(2, 0,
gettext("%s: Group "
"execution not permitted "
"on a lockable file\n"),
path);
return (old_mode);
}
}
/* is setgid on execution requested? */
if (scheck == 1 && (perms_msk & GROUP & SETID)
== (GROUP & SETID)) {
/* not locking, too! */
if (lcheck == 1 &&
((perms_msk & GROUP & EXEC) ==
(GROUP & EXEC)) &&
!S_ISDIR(new_mode)) {
errmsg(1, 4,
gettext("Set-group-ID and "
"locking not permitted "
"together\n"));
}
/*
* not if the file is already
* lockable
*/
if (((new_mode & GROUP &
(LOCK | EXEC)) == LOCK) &&
!S_ISDIR(new_mode)) {
errmsg(2, 0,
gettext("%s: Set-group-ID "
"not permitted on a "
"lockable file\n"), path);
return (old_mode);
}
}
/* is setid on execution requested? */
if ((scheck == 1) &&
((new_mode & S_IFMT) != S_IFDIR)) {
/*
* the corresponding execution must
* be requested or already set
*/
if (((new_mode | perms_msk) &
who_msk & EXEC & (USER | GROUP)) !=
(who_msk & EXEC & (USER | GROUP))) {
errmsg(2, 0,
gettext("%s: Execute "
"permission required "
"for set-ID on "
"execution \n"),
path);
return (old_mode);
}
}
/* is locking requested? */
if (lcheck == 1) {
/*
* not if the file has group execution
* set.
* NOTE: this also covers files with
* setgid
*/
if ((new_mode & GROUP & EXEC) ==
(GROUP & EXEC) &&
!S_ISDIR(new_mode)) {
errmsg(2, 0,
gettext("%s: Locking not "
"permitted on "
"a group executable "
"file\n"),
path);
return (old_mode);
}
}
if ((grp_change = (perms_msk & GROUP_RWX) >> 3)
!= 0) {
*group_clear_bits &= ~grp_change;
*group_set_bits |= grp_change;
}
/* create new mode */
new_mode |= perms_msk;
break;
case '-':
if (who_empty) {
perms_msk &= ~umsk;
}
/* don't turn off locking, unless it's on */
if (lcheck == 1 && scheck == 0 &&
(new_mode & GROUP & (LOCK | EXEC)) !=
LOCK) {
perms_msk &= ~LOCK;
}
/* don't turn off setgid, unless it's on */
if (scheck == 1 &&
((new_mode & S_IFMT) != S_IFDIR) &&
lcheck == 0 &&
(new_mode & GROUP & (LOCK | EXEC)) ==
LOCK) {
perms_msk &= ~(GROUP & SETID);
}
/*
* if execution is being turned off and the
* corresponding setid is not, turn setid off,
* too & warn the user
*/
if (xcheck == 1 && scheck == 0 &&
((who_msk & GROUP) == GROUP ||
(who_msk & USER) == USER) &&
(new_mode & who_msk & (SETID | EXEC)) ==
(who_msk & (SETID | EXEC)) &&
!S_ISDIR(new_mode)) {
errmsg(2, 0,
gettext("%s: Corresponding set-ID "
"also disabled on file since "
"set-ID requires execute "
"permission\n"),
path);
if ((perms_msk & USER & SETID) !=
(USER & SETID) && (new_mode &
USER & (SETID | EXEC)) ==
(who_msk & USER &
(SETID | EXEC))) {
perms_msk |= USER & SETID;
}
if ((perms_msk & GROUP & SETID) !=
(GROUP & SETID) &&
(new_mode & GROUP &
(SETID | EXEC)) ==
(who_msk & GROUP &
(SETID | EXEC))) {
perms_msk |= GROUP & SETID;
}
}
if ((grp_change = (perms_msk & GROUP_RWX) >> 3)
!= 0) {
*group_clear_bits |= grp_change;
*group_set_bits &= ~grp_change;
}
/* create new mode */
new_mode &= ~perms_msk;
break;
case '=':
if (who_empty) {
perms_msk &= ~umsk;
}
/* is locking requested? */
if (lcheck == 1) {
/* not group execution, too! */
if ((perms_msk & GROUP & EXEC) ==
(GROUP & EXEC) &&
!S_ISDIR(new_mode)) {
errmsg(1, 3,
gettext("Group execution "
"and locking not "
"permitted together\n"));
}
/*
* if the file has group execution set,
* turn it off!
*/
if ((who_msk & GROUP) != GROUP) {
new_mode &= ~(GROUP & EXEC);
}
}
/*
* is setid on execution requested? the
* corresponding execution must be requested,
* too!
*/
if (scheck == 1 &&
(perms_msk & EXEC & (USER | GROUP)) !=
(who_msk & EXEC & (USER | GROUP)) &&
!S_ISDIR(new_mode)) {
errmsg(1, 2,
gettext("Execute permission "
"required for set-ID on "
"execution\n"));
}
/*
* The ISGID bit on directories will not be
* changed when the mode argument is a string
* with "=".
*/
if ((old_mode & S_IFMT) == S_IFDIR)
perms_msk = (perms_msk &
~S_ISGID) | (old_mode & S_ISGID);
/*
* create new mode:
* clear the who_msk bits
* set the perms_mks bits (which have
* been trimmed to fit the who_msk.
*/
if ((grp_change = (perms_msk & GROUP_RWX) >> 3)
!= 0) {
*group_clear_bits = GROUP_RWX >> 3;
*group_set_bits = grp_change;
}
new_mode &= ~who_msk;
new_mode |= perms_msk;
break;
}
}
} while (*msp++ == ',');
if (*--msp || operand_empty == 0) {
errmsg(1, 5, gettext("invalid mode\n"));
}
return (new_mode);
}
mode_t
abs(mode_t mode, o_mode_t *group_clear_bits, o_mode_t *group_set_bits)
{
int c;
mode_t i;
for (i = 0; (c = *msp) >= '0' && c <= '7'; msp++)
i = (mode_t)((i << 3) + (c - '0'));
if (*msp)
errmsg(1, 6, gettext("invalid mode\n"));
/*
* The ISGID bit on directories will not be changed when the mode argument is
* octal numeric. Only "g+s" and "g-s" arguments can change ISGID bit when
* applied to directories.
*/
*group_clear_bits = GROUP_RWX >> 3;
*group_set_bits = (i & GROUP_RWX) >> 3;
if ((mode & S_IFMT) == S_IFDIR)
return ((i & ~S_ISGID) | (mode & S_ISGID));
return (i);
}
static mode_t
who(void)
{
mode_t m;
m = WHO_EMPTY;
for (; ; msp++) {
switch (*msp) {
case 'u':
m |= USER;
continue;
case 'g':
m |= GROUP;
continue;
case 'o':
m |= OTHER;
continue;
case 'a':
m |= ALL;
continue;
default:
return (m);
}
}
}
static int
what(void)
{
switch (*msp) {
case '+':
case '-':
case '=':
return (*msp++);
}
return (0);
}