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/*
* Copyright (C) 2014 Colin Walters <walters@verbum.org>
*
* SPDX-License-Identifier: LGPL-2.0+
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "ostree-linuxfsutil.h"
#include "otutil.h"
#include <fcntl.h>
#include <sys/ioctl.h>
// This should be the only file including linux/fs.h; see
// https://sourceware.org/glibc/wiki/Release/2.36#Usage_of_.3Clinux.2Fmount.h.3E_and_.3Csys.2Fmount.h.3E
// https://github.com/ostreedev/ostree/issues/2685
#include <linux/fs.h>
#include <ext2fs/ext2_fs.h>
/**
* _ostree_linuxfs_fd_alter_immutable_flag:
* @fd: A file descriptor
* @new_immutable_state: Set this to %TRUE to make the file immutable, %FALSE to unset the flag
* @cancellable: Cancellable
* @error: GError
*
* Alter the immutable flag of object referred to by @fd; may be a
* regular file or a directory.
*
* If the operation is not supported by the underlying filesystem, or
* we are running without sufficient privileges, this function will
* silently do nothing.
*/
gboolean
_ostree_linuxfs_fd_alter_immutable_flag (int fd,
gboolean new_immutable_state,
GCancellable *cancellable,
GError **error)
{
static gint no_alter_immutable = 0;
if (g_atomic_int_get (&no_alter_immutable))
return TRUE;
int flags = 0;
int r = ioctl (fd, EXT2_IOC_GETFLAGS, &flags);
if (r == -1)
{
if (errno == EPERM)
g_atomic_int_set (&no_alter_immutable, 1);
else if (errno == EOPNOTSUPP || errno == ENOTTY)
;
else
return glnx_throw_errno_prefix (error, "ioctl(EXT2_IOC_GETFLAGS)");
}
else
{
gboolean prev_immutable_state = (flags & EXT2_IMMUTABLE_FL) > 0;
if (prev_immutable_state == new_immutable_state)
return TRUE; /* Nothing to do */
if (new_immutable_state)
flags |= EXT2_IMMUTABLE_FL;
else
flags &= ~EXT2_IMMUTABLE_FL;
r = ioctl (fd, EXT2_IOC_SETFLAGS, &flags);
if (r == -1)
{
if (errno == EPERM)
g_atomic_int_set (&no_alter_immutable, 1);
else if (errno == EOPNOTSUPP || errno == ENOTTY)
;
else
return glnx_throw_errno_prefix (error, "ioctl(EXT2_IOC_SETFLAGS)");
}
}
return TRUE;
}
/* Wrapper for FIFREEZE ioctl.
* This is split into a separate wrapped API for
* reasons around conflicts between glibc and linux/fs.h
* includes; see above.
*/
int
_ostree_linuxfs_filesystem_freeze (int fd)
{
return TEMP_FAILURE_RETRY (ioctl (fd, FIFREEZE, 0));
}
/* Wrapper for FITHAW ioctl. See above. */
int
_ostree_linuxfs_filesystem_thaw (int fd)
{
return TEMP_FAILURE_RETRY (ioctl (fd, FITHAW, 0));
}
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