292 lines
8.1 KiB
C
292 lines
8.1 KiB
C
/* Get permissions of a file. -*- coding: utf-8 -*-
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Copyright (C) 2002-2003, 2005-2024 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible. */
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#include <config.h>
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#include <string.h>
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#include "acl.h"
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#include "acl-internal.h"
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/* Read the permissions of a file into CTX. If DESC is a valid file descriptor,
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use file descriptor operations, else use filename based operations on NAME.
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MODE is the file mode obtained from a previous stat call.
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Return 0 if successful. Return -1 and set errno upon failure. */
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int
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get_permissions (const char *name, int desc, mode_t mode,
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struct permission_context *ctx)
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{
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memset (ctx, 0, sizeof *ctx);
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ctx->mode = mode;
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#if USE_ACL && HAVE_ACL_GET_FILE
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/* POSIX 1003.1e (draft 17 -- abandoned) specific version. */
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/* Linux, FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */
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# if !HAVE_ACL_TYPE_EXTENDED
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/* Linux, FreeBSD, IRIX, Tru64, Cygwin >= 2.5 */
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if (HAVE_ACL_GET_FD && desc != -1)
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ctx->acl = acl_get_fd (desc);
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else
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ctx->acl = acl_get_file (name, ACL_TYPE_ACCESS);
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if (ctx->acl == NULL)
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return acl_errno_valid (errno) ? -1 : 0;
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/* With POSIX ACLs, a file cannot have "no" acl; a file without
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extended permissions has a "minimal" acl which is equivalent to the
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file mode. */
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if (S_ISDIR (mode))
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{
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ctx->default_acl = acl_get_file (name, ACL_TYPE_DEFAULT);
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if (ctx->default_acl == NULL)
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return -1;
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}
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# if HAVE_ACL_TYPE_NFS4 /* FreeBSD */
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/* TODO (see set_permissions). */
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# endif
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# else /* HAVE_ACL_TYPE_EXTENDED */
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/* Mac OS X */
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/* On Mac OS X, acl_get_file (name, ACL_TYPE_ACCESS)
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and acl_get_file (name, ACL_TYPE_DEFAULT)
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always return NULL / EINVAL. You have to use
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acl_get_file (name, ACL_TYPE_EXTENDED)
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or acl_get_fd (open (name, ...))
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to retrieve an ACL.
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On the other hand,
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acl_set_file (name, ACL_TYPE_ACCESS, acl)
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and acl_set_file (name, ACL_TYPE_DEFAULT, acl)
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have the same effect as
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acl_set_file (name, ACL_TYPE_EXTENDED, acl):
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Each of these calls sets the file's ACL. */
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if (HAVE_ACL_GET_FD && desc != -1)
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ctx->acl = acl_get_fd (desc);
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else
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ctx->acl = acl_get_file (name, ACL_TYPE_EXTENDED);
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if (ctx->acl == NULL)
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return acl_errno_valid (errno) ? -1 : 0;
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# endif
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#elif USE_ACL && defined GETACL /* Solaris, Cygwin, not HP-UX */
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/* Solaris 2.5 through Solaris 10, Cygwin, and contemporaneous versions
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of Unixware. The acl() call returns the access and default ACL both
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at once. */
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# ifdef ACE_GETACL
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/* Solaris also has a different variant of ACLs, used in ZFS and NFSv4
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file systems (whereas the other ones are used in UFS file systems).
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There is an API
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pathconf (name, _PC_ACL_ENABLED)
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fpathconf (desc, _PC_ACL_ENABLED)
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that allows us to determine which of the two kinds of ACLs is supported
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for the given file. But some file systems may implement this call
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incorrectly, so better not use it.
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When fetching the source ACL, we simply fetch both ACL types.
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When setting the destination ACL, we try either ACL types, assuming
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that the kernel will translate the ACL from one form to the other.
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(See in <https://docs.oracle.com/cd/E86824_01/html/E54765/acl-2.html>
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the description of ENOTSUP.) */
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for (;;)
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{
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int ret;
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if (desc != -1)
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ret = facl (desc, ACE_GETACLCNT, 0, NULL);
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else
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ret = acl (name, ACE_GETACLCNT, 0, NULL);
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if (ret < 0)
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{
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if (errno == ENOSYS || errno == EINVAL)
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ret = 0;
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else
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return -1;
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}
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ctx->ace_count = ret;
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if (ctx->ace_count == 0)
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break;
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ctx->ace_entries = (ace_t *) malloc (ctx->ace_count * sizeof (ace_t));
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if (ctx->ace_entries == NULL)
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{
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errno = ENOMEM;
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return -1;
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}
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if (desc != -1)
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ret = facl (desc, ACE_GETACL, ctx->ace_count, ctx->ace_entries);
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else
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ret = acl (name, ACE_GETACL, ctx->ace_count, ctx->ace_entries);
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if (ret < 0)
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{
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if (errno == ENOSYS || errno == EINVAL)
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{
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free (ctx->ace_entries);
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ctx->ace_entries = NULL;
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ctx->ace_count = 0;
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break;
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}
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else
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return -1;
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}
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if (ret <= ctx->ace_count)
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{
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ctx->ace_count = ret;
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break;
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}
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/* Huh? The number of ACL entries has increased since the last call.
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Repeat. */
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free (ctx->ace_entries);
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ctx->ace_entries = NULL;
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}
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# endif
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for (;;)
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{
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int ret;
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if (desc != -1)
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ret = facl (desc, GETACLCNT, 0, NULL);
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else
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ret = acl (name, GETACLCNT, 0, NULL);
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if (ret < 0)
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{
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if (errno == ENOSYS || errno == ENOTSUP || errno == EOPNOTSUPP)
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ret = 0;
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else
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return -1;
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}
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ctx->count = ret;
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if (ctx->count == 0)
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break;
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ctx->entries = (aclent_t *) malloc (ctx->count * sizeof (aclent_t));
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if (ctx->entries == NULL)
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{
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errno = ENOMEM;
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return -1;
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}
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if (desc != -1)
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ret = facl (desc, GETACL, ctx->count, ctx->entries);
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else
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ret = acl (name, GETACL, ctx->count, ctx->entries);
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if (ret < 0)
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{
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if (errno == ENOSYS || errno == ENOTSUP || errno == EOPNOTSUPP)
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{
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free (ctx->entries);
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ctx->entries = NULL;
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ctx->count = 0;
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break;
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}
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else
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return -1;
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}
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if (ret <= ctx->count)
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{
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ctx->count = ret;
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break;
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}
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/* Huh? The number of ACL entries has increased since the last call.
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Repeat. */
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free (ctx->entries);
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ctx->entries = NULL;
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}
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#elif USE_ACL && HAVE_GETACL /* HP-UX */
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{
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int ret;
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if (desc != -1)
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ret = fgetacl (desc, NACLENTRIES, ctx->entries);
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else
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ret = getacl (name, NACLENTRIES, ctx->entries);
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if (ret < 0)
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{
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if (errno == ENOSYS || errno == EOPNOTSUPP || errno == ENOTSUP)
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ret = 0;
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else
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return -1;
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}
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else if (ret > NACLENTRIES)
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/* If NACLENTRIES cannot be trusted, use dynamic memory allocation. */
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abort ();
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ctx->count = ret;
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# if HAVE_ACLV_H
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ret = acl ((char *) name, ACL_GET, NACLVENTRIES, ctx->aclv_entries);
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if (ret < 0)
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{
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if (errno == ENOSYS || errno == EOPNOTSUPP || errno == EINVAL)
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ret = 0;
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else
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return -2;
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}
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else if (ret > NACLVENTRIES)
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/* If NACLVENTRIES cannot be trusted, use dynamic memory allocation. */
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abort ();
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ctx->aclv_count = ret;
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# endif
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}
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#elif USE_ACL && HAVE_ACLX_GET && ACL_AIX_WIP /* AIX */
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/* TODO (see set_permissions). */
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#elif USE_ACL && HAVE_STATACL /* older AIX */
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{
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int ret;
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if (desc != -1)
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ret = fstatacl (desc, STX_NORMAL, &ctx->u.a, sizeof ctx->u);
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else
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ret = statacl ((char *) name, STX_NORMAL, &ctx->u.a, sizeof ctx->u);
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if (ret == 0)
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ctx->have_u = true;
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}
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#elif USE_ACL && HAVE_ACLSORT /* NonStop Kernel */
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{
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int ret = acl ((char *) name, ACL_GET, NACLENTRIES, ctx->entries);
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if (ret < 0)
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return -1;
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else if (ret > NACLENTRIES)
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/* If NACLENTRIES cannot be trusted, use dynamic memory allocation. */
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abort ();
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ctx->count = ret;
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}
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#endif
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return 0;
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}
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