ostree/src/libostree/ostree-linuxfsutil.c

134 lines
3.9 KiB
C

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
*
* Copyright (C) 2014 Colin Walters <walters@verbum.org>
*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include "ostree-linuxfsutil.h"
#include "otutil.h"
#include <fcntl.h>
#include <sys/ioctl.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)
{
gboolean ret = FALSE;
unsigned long flags;
int r;
static gint no_alter_immutable = 0;
if (g_atomic_int_get (&no_alter_immutable))
return TRUE;
r = ioctl (fd, EXT2_IOC_GETFLAGS, &flags);
if (r == -1)
{
int errsv = errno;
if (errsv == EPERM)
g_atomic_int_set (&no_alter_immutable, 1);
else if (errsv == EOPNOTSUPP || errsv == ENOTTY)
;
else
{
g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
"ioctl(EXT2_IOC_GETFLAGS): %s",
g_strerror (errsv));
goto out;
}
}
else
{
if (new_immutable_state)
flags |= EXT2_IMMUTABLE_FL;
else
flags &= ~EXT2_IMMUTABLE_FL;
r = ioctl (fd, EXT2_IOC_SETFLAGS, &flags);
if (r == -1)
{
int errsv = errno;
if (errsv == EPERM)
g_atomic_int_set (&no_alter_immutable, 1);
else if (errsv == EOPNOTSUPP || errsv == ENOTTY)
;
else
{
g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
"ioctl(EXT2_IOC_GETFLAGS): %s",
g_strerror (errsv));
goto out;
}
}
}
ret = TRUE;
out:
return ret;
}
gboolean
_ostree_linuxfs_alter_immutable_flag (GFile *path,
gboolean new_immutable_state,
GCancellable *cancellable,
GError **error)
{
gboolean ret = FALSE;
glnx_fd_close int fd = -1;
if (g_cancellable_set_error_if_cancelled (cancellable, error))
return FALSE;
fd = open (gs_file_get_path_cached (path), O_RDONLY|O_NONBLOCK|O_LARGEFILE);
if (fd == -1)
{
int errsv = errno;
g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
"open(%s): %s",
gs_file_get_path_cached (path),
g_strerror (errsv));
goto out;
}
if (!_ostree_linuxfs_fd_alter_immutable_flag (fd, new_immutable_state,
cancellable, error))
goto out;
ret = TRUE;
out:
return ret;
}