(acl_entries): Add fallback implementation for POSIX ACL

systems other than Linux.
(chmod_or_fchmod): New function: use fchmod when possible,
and chmod otherwise.
(file_has_acl): Add a POSIX ACL implementation, with a
Linux-specific subcase.
(copy_acl): Add: copy an acl and S_ISUID, S_ISGID, and
S_ISVTX from one file to another.  Fall back to fchmod/chmod when
acls are unsupported.
(set_acl): Add: set a file's acl and S_ISUID, S_ISGID, and
S_ISVTX to a defined value.  Fall back to fchmod/chmod when acls
are unsupported.
This commit is contained in:
Jim Meyering 2005-12-17 10:31:33 +00:00
parent 9566c9c9d3
commit 4a12f5ebcf

376
lib/acl.c
View File

@ -16,48 +16,394 @@
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Written by Paul Eggert. */
Written by Paul Eggert and Andreas Gruenbacher. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifndef S_ISLNK
# define S_ISLNK(Mode) 0
#endif
#ifdef HAVE_ACL_LIBACL_H
# include <acl/libacl.h>
#endif
#include "acl.h"
#include "error.h"
#include "quote.h"
#include <errno.h>
#ifndef ENOSYS
# define ENOSYS (-1)
#endif
#ifndef MIN_ACL_ENTRIES
# define MIN_ACL_ENTRIES 4
#ifndef ENOTSUP
# define ENOTSUP (-1)
#endif
/* Return 1 if FILE has a nontrivial access control list, 0 if not,
and -1 (setting errno) if an error is encountered. */
#if ENABLE_NLS
# include <libintl.h>
# define _(Text) gettext (Text)
#else
# define _(Text) Text
#endif
#ifndef HAVE_FCHMOD
# define HAVE_FCHMOD false
# define fchmod(fd, mode) (-1)
#endif
/* POSIX 1003.1e (draft 17) */
#ifndef HAVE_ACL_GET_FD
# define HAVE_ACL_GET_FD false
# define acl_get_fd(fd) (NULL)
#endif
/* POSIX 1003.1e (draft 17) */
#ifndef HAVE_ACL_SET_FD
# define HAVE_ACL_SET_FD false
# define acl_set_fd(fd, acl) (-1)
#endif
/* Linux-specific */
#ifndef HAVE_ACL_EXTENDED_FILE
# define HAVE_ACL_EXTENDED_FILE false
# define acl_extended_file(name) (-1)
#endif
/* Linux-specific */
#ifndef HAVE_ACL_FROM_MODE
# define HAVE_ACL_FROM_MODE false
# define acl_from_mode(mode) (NULL)
#endif
/* We detect presence of POSIX 1003.1e (draft 17 -- abandoned) support
by checking for HAVE_ACL_GET_FILE, HAVE_ACL_SET_FILE, and HAVE_ACL_FREE.
Systems that have acl_get_file, acl_set_file, and acl_free must also
have acl_to_text, acl_from_text, and acl_delete_def_file (all defined
in the draft); systems that don't would hit #error statements here. */
#if USE_ACL && HAVE_ACL_GET_FILE && !HAVE_ACL_ENTRIES
# ifndef HAVE_ACL_TO_TEXT
# error Must have acl_to_text (see POSIX 1003.1e draft 17).
# endif
/* Return the number of entries in ACL. Linux implements acl_entries
as a more efficient extension than using this workaround. */
static int
acl_entries (acl_t acl)
{
char *text = acl_to_text (acl, NULL), *t;
int entries;
if (text == NULL)
return -1;
for (entries = 0, t = text; ; t++, entries++) {
t = strchr (t, '\n');
if (t == NULL)
break;
}
acl_free (text);
return entries;
}
#endif
/* If DESC is a valid file descriptor use fchmod to change the
file's mode to MODE on systems that have fchown. On systems
that don't have fchown and if DESC is invalid, use chown on
NAME instead. */
int
file_has_acl (char const *file, struct stat const *filestat)
chmod_or_fchmod (const char *name, int desc, mode_t mode)
{
/* FIXME: This implementation should work on recent-enough versions
of HP-UX, Solaris, and Unixware, but it simply returns 0 with
POSIX 1003.1e (draft 17 -- abandoned), AIX, GNU/Linux, Irix, and
Tru64. Please see Samba's source/lib/sysacls.c file for
fix-related ideas. */
if (HAVE_FCHMOD && desc != -1)
return fchmod (desc, mode);
else
return chmod (name, mode);
}
#if HAVE_ACL && defined GETACLCNT
if (! S_ISLNK (filestat->st_mode))
/* Return 1 if NAME has a nontrivial access control list, 0 if
NAME only has no or a base access control list, and -1 on
error. SB must be set to the stat buffer of FILE. */
int
file_has_acl (char const *name, struct stat const *sb)
{
#if USE_ACL && HAVE_ACL && defined GETACLCNT
/* This implementation should work on recent-enough versions of HP-UX,
Solaris, and Unixware. */
# ifndef MIN_ACL_ENTRIES
# define MIN_ACL_ENTRIES 4
# endif
if (! S_ISLNK (sb->st_mode))
{
int n = acl (file, GETACLCNT, 0, NULL);
int n = acl (name, GETACLCNT, 0, NULL);
return n < 0 ? (errno == ENOSYS ? 0 : -1) : (MIN_ACL_ENTRIES < n);
}
#elif USE_ACL && HAVE_ACL_GET_FILE && HAVE_ACL_FREE
/* POSIX 1003.1e (draft 17 -- abandoned) specific version. */
if (! S_ISLNK (sb->st_mode))
{
int ret;
if (HAVE_ACL_EXTENDED_FILE)
ret = acl_extended_file (name);
else
{
acl_t acl = acl_get_file (name, ACL_TYPE_ACCESS);
if (acl)
{
ret = (3 < acl_entries (acl));
acl_free (acl);
if (ret == 0 && S_ISDIR (sb->st_mode))
{
acl = acl_get_file (name, ACL_TYPE_DEFAULT);
if (acl)
{
ret = (0 < acl_entries (acl));
acl_free (acl);
}
else
ret = -1;
}
}
else
ret = -1;
}
if (ret < 0)
return (errno == ENOSYS || errno == ENOTSUP) ? 0 : -1;
return ret;
}
#endif
/* FIXME: Add support for AIX, Irix, and Tru64. Please see Samba's
source/lib/sysacls.c file for fix-related ideas. */
return 0;
}
/* Copy access control lists from one file to another. If SOURCE_DESC is
a valid file descriptor, use file descriptor operations, else use
filename based operations on SRC_NAME. Likewise for DEST_DESC and
DEST_NAME.
If access control lists are not available, fchmod the target file to
MODE. Also sets the non-permission bits of the destination file
(S_ISUID, S_ISGID, S_ISVTX) to those from MODE if any are set.
System call return value semantics. */
int
copy_acl (const char *src_name, int source_desc, const char *dst_name,
int dest_desc, mode_t mode)
{
int ret;
#if USE_ACL && HAVE_ACL_GET_FILE && HAVE_ACL_SET_FILE && HAVE_ACL_FREE
/* POSIX 1003.1e (draft 17 -- abandoned) specific version. */
acl_t acl;
if (HAVE_ACL_GET_FD && source_desc != -1)
acl = acl_get_fd (source_desc);
else
acl = acl_get_file (src_name, ACL_TYPE_ACCESS);
if (acl == NULL)
{
if (errno == ENOSYS || errno == ENOTSUP)
return set_acl (dst_name, dest_desc, mode);
else
{
error (0, errno, "%s", quote (src_name));
return -1;
}
}
if (HAVE_ACL_SET_FD && dest_desc != -1)
ret = acl_set_fd (dest_desc, acl);
else
ret = acl_set_file (dst_name, ACL_TYPE_ACCESS, acl);
if (ret != 0)
{
int saved_errno = errno;
if (errno == ENOSYS || errno == ENOTSUP)
{
int n = acl_entries (acl);
acl_free (acl);
if (n == 3)
{
if (chmod_or_fchmod (dst_name, dest_desc, mode) != 0)
saved_errno = errno;
else
return 0;
}
else
chmod_or_fchmod (dst_name, dest_desc, mode);
}
else
{
acl_free (acl);
chmod_or_fchmod (dst_name, dest_desc, mode);
}
error (0, saved_errno, _("preserving permissions for %s"),
quote (dst_name));
return -1;
}
else
acl_free (acl);
if (mode & (S_ISUID | S_ISGID | S_ISVTX))
{
/* We did not call chmod so far, so the special bits have not yet
been set. */
if (chmod_or_fchmod (dst_name, dest_desc, mode) != 0)
{
error (0, errno, _("preserving permissions for %s"),
quote (dst_name));
return -1;
}
}
if (S_ISDIR (mode))
{
acl = acl_get_file (src_name, ACL_TYPE_DEFAULT);
if (acl == NULL)
{
error (0, errno, "%s", quote (src_name));
return -1;
}
if (acl_set_file (dst_name, ACL_TYPE_DEFAULT, acl))
{
error (0, errno, _("preserving permissions for %s"),
quote (dst_name));
acl_free (acl);
return -1;
}
else
acl_free (acl);
}
return 0;
#else
ret = chmod_or_fchmod (dst_name, dest_desc, mode);
if (ret != 0)
error (0, errno, _("preserving permissions for %s"), quote (dst_name));
return ret;
#endif
}
/* Set the access control lists of a file. If DESC is a valid file
descriptor, use file descriptor operations where available, else use
filename based operations on NAME. If access control lists are not
available, fchmod the target file to MODE. Also sets the
non-permission bits of the destination file (S_ISUID, S_ISGID, S_ISVTX)
to those from MODE if any are set. System call return value
semantics. */
int
set_acl (char const *name, int desc, mode_t mode)
{
#if USE_ACL && HAVE_ACL_SET_FILE && HAVE_ACL_FREE
/* POSIX 1003.1e draft 17 (abandoned) specific version. */
/* We must also have have_acl_from_text and acl_delete_def_file.
(acl_delete_def_file could be emulated with acl_init followed
by acl_set_file, but acl_set_file with an empty acl is
unspecified.) */
# ifndef HAVE_ACL_FROM_TEXT
# error Must have acl_from_text (see POSIX 1003.1e draft 17).
# endif
# ifndef HAVE_ACL_DELETE_DEF_FILE
# error Must have acl_delete_def_file (see POSIX 1003.1e draft 17).
# endif
acl_t acl;
int ret;
if (HAVE_ACL_FROM_MODE)
{
acl = acl_from_mode (mode);
if (!acl)
{
error (0, errno, "%s", quote (name));
return -1;
}
}
else
{
char acl_text[] = "u::---,g::---,o::---";
if (mode & S_IRUSR) acl_text[ 3] = 'r';
if (mode & S_IWUSR) acl_text[ 4] = 'w';
if (mode & S_IXUSR) acl_text[ 5] = 'x';
if (mode & S_IRGRP) acl_text[10] = 'r';
if (mode & S_IWGRP) acl_text[11] = 'w';
if (mode & S_IXGRP) acl_text[12] = 'x';
if (mode & S_IROTH) acl_text[17] = 'r';
if (mode & S_IWOTH) acl_text[18] = 'w';
if (mode & S_IXOTH) acl_text[19] = 'x';
acl = acl_from_text (acl_text);
if (!acl)
{
error (0, errno, "%s", quote (name));
return -1;
}
}
if (HAVE_ACL_SET_FD && desc != -1)
ret = acl_set_fd (desc, acl);
else
ret = acl_set_file (name, ACL_TYPE_ACCESS, acl);
if (ret != 0)
{
int saved_errno = errno;
acl_free (acl);
if (errno == ENOTSUP || errno == ENOSYS)
{
if (chmod_or_fchmod (name, desc, mode) != 0)
saved_errno = errno;
else
return 0;
}
error (0, saved_errno, _("setting permissions for %s"), quote (name));
return -1;
}
else
acl_free (acl);
if (S_ISDIR (mode) && acl_delete_def_file (name))
{
error (0, errno, _("setting permissions for %s"), quote (name));
return -1;
}
if (mode & (S_ISUID | S_ISGID | S_ISVTX))
{
/* We did not call chmod so far, so the special bits have not yet
been set. */
if (chmod_or_fchmod (name, desc, mode))
{
error (0, errno, _("preserving permissions for %s"), quote (name));
return -1;
}
}
return 0;
#else
int ret = chmod_or_fchmod (name, desc, mode);
if (ret)
error (0, errno, _("setting permissions for %s"), quote (name));
return ret;
#endif
}