995 lines
28 KiB
C
995 lines
28 KiB
C
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
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*
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* Copyright (C) 2014,2015 Colin Walters <walters@verbum.org>.
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*
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* Portions derived from systemd:
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* Copyright 2010 Lennart Poettering
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include "config.h"
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <sys/ioctl.h>
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#include <sys/sendfile.h>
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#include <errno.h>
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/* See linux.git/fs/btrfs/ioctl.h */
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#define BTRFS_IOCTL_MAGIC 0x94
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#define BTRFS_IOC_CLONE _IOW(BTRFS_IOCTL_MAGIC, 9, int)
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#include <glnx-fdio.h>
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#include <glnx-dirfd.h>
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#include <glnx-alloca.h>
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#include <glnx-errors.h>
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#include <glnx-xattrs.h>
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#include <glnx-backport-autoptr.h>
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#include <glnx-local-alloc.h>
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#include <glnx-missing.h>
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/* Returns the number of chars needed to format variables of the
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* specified type as a decimal string. Adds in extra space for a
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* negative '-' prefix (hence works correctly on signed
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* types). Includes space for the trailing NUL. */
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#define DECIMAL_STR_MAX(type) \
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(2+(sizeof(type) <= 1 ? 3 : \
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sizeof(type) <= 2 ? 5 : \
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sizeof(type) <= 4 ? 10 : \
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sizeof(type) <= 8 ? 20 : sizeof(int[-2*(sizeof(type) > 8)])))
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/* An implementation of renameat2(..., RENAME_NOREPLACE)
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* with fallback to a non-atomic version.
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*/
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int
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glnx_renameat2_noreplace (int olddirfd, const char *oldpath,
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int newdirfd, const char *newpath)
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{
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#ifndef ENABLE_WRPSEUDO_COMPAT
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if (renameat2 (olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE) < 0)
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{
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if (errno == EINVAL || errno == ENOSYS)
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{
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/* Fall through */
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}
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else
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{
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return -1;
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}
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}
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else
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return TRUE;
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#endif
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if (linkat (olddirfd, oldpath, newdirfd, newpath, 0) < 0)
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return -1;
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if (unlinkat (olddirfd, oldpath, 0) < 0)
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return -1;
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return 0;
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}
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static gboolean
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rename_file_noreplace_at (int olddirfd, const char *oldpath,
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int newdirfd, const char *newpath,
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gboolean ignore_eexist,
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GError **error)
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{
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if (glnx_renameat2_noreplace (olddirfd, oldpath,
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newdirfd, newpath) < 0)
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{
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if (errno == EEXIST && ignore_eexist)
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{
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(void) unlinkat (olddirfd, oldpath, 0);
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return TRUE;
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}
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else
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return glnx_throw_errno (error);
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}
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return TRUE;
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}
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/* An implementation of renameat2(..., RENAME_EXCHANGE)
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* with fallback to a non-atomic version.
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*/
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int
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glnx_renameat2_exchange (int olddirfd, const char *oldpath,
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int newdirfd, const char *newpath)
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{
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#ifndef ENABLE_WRPSEUDO_COMPAT
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if (renameat2 (olddirfd, oldpath, newdirfd, newpath, RENAME_EXCHANGE) == 0)
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return 0;
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else
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{
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if (errno == ENOSYS || errno == EINVAL)
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{
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/* Fall through */
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}
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else
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{
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return -1;
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}
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}
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#endif
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/* Fallback */
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{ const char *old_tmp_name = glnx_strjoina (oldpath, ".XXXXXX");
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/* Move old out of the way */
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if (renameat (olddirfd, oldpath, olddirfd, old_tmp_name) < 0)
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return -1;
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/* Now move new into its place */
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if (renameat (newdirfd, newpath, olddirfd, oldpath) < 0)
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return -1;
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/* And finally old(tmp) into new */
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if (renameat (olddirfd, old_tmp_name, newdirfd, newpath) < 0)
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return -1;
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}
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return 0;
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}
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gboolean
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glnx_open_tmpfile_linkable_at (int dfd,
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const char *subpath,
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int flags,
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int *out_fd,
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char **out_path,
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GError **error)
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{
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glnx_fd_close int fd = -1;
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int count;
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/* Don't allow O_EXCL, as that has a special meaning for O_TMPFILE */
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g_return_val_if_fail ((flags & O_EXCL) == 0, FALSE);
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/* Creates a temporary file, that shall be renamed to "target"
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* later. If possible, this uses O_TMPFILE – in which case
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* "ret_path" will be returned as NULL. If not possible a the
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* tempoary path name used is returned in "ret_path". Use
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* link_tmpfile() below to rename the result after writing the file
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* in full. */
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#if defined(O_TMPFILE) && !defined(DISABLE_OTMPFILE) && !defined(ENABLE_WRPSEUDO_COMPAT)
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fd = openat (dfd, subpath, O_TMPFILE|flags, 0600);
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if (fd == -1 && !(errno == ENOSYS || errno == EISDIR || errno == EOPNOTSUPP))
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return glnx_throw_errno_prefix (error, "open(O_TMPFILE)");
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if (fd != -1)
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{
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*out_fd = fd;
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fd = -1;
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*out_path = NULL;
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return TRUE;
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}
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/* Fallthrough */
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#endif
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{ g_autofree char *tmp = g_strconcat (subpath, "/tmp.XXXXXX", NULL);
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const guint count_max = 100;
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for (count = 0; count < count_max; count++)
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{
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glnx_gen_temp_name (tmp);
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fd = openat (dfd, tmp, O_CREAT|O_EXCL|O_NOFOLLOW|O_NOCTTY|flags, 0600);
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if (fd < 0)
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{
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if (errno == EEXIST)
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continue;
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else
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return glnx_throw_errno_prefix (error, "Creating temp file");
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}
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else
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{
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*out_fd = fd;
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fd = -1;
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*out_path = g_steal_pointer (&tmp);
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return TRUE;
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}
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}
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}
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_EXISTS,
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"Exhausted %u attempts to create temporary file", count);
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return FALSE;
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}
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gboolean
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glnx_link_tmpfile_at (int dfd,
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GLnxLinkTmpfileReplaceMode mode,
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int fd,
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const char *tmpfile_path,
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int target_dfd,
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const char *target,
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GError **error)
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{
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const gboolean replace = (mode == GLNX_LINK_TMPFILE_REPLACE);
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const gboolean ignore_eexist = (mode == GLNX_LINK_TMPFILE_NOREPLACE_IGNORE_EXIST);
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g_return_val_if_fail (fd >= 0, FALSE);
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/* Unlike the original systemd code, this function also supports
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* replacing existing files.
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*/
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/* We have `tmpfile_path` for old systems without O_TMPFILE. */
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if (tmpfile_path)
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{
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if (replace)
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{
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/* We have a regular tempfile, we're overwriting - this is a
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* simple renameat().
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*/
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if (renameat (dfd, tmpfile_path, target_dfd, target) < 0)
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{
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int errsv = errno;
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(void) unlinkat (dfd, tmpfile_path, 0);
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errno = errsv;
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return glnx_throw_errno_prefix (error, "renameat");
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}
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}
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else
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{
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/* We need to use renameat2(..., NOREPLACE) or emulate it */
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if (!rename_file_noreplace_at (dfd, tmpfile_path, target_dfd, target,
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ignore_eexist,
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error))
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{
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(void) unlinkat (dfd, tmpfile_path, 0);
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return FALSE;
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}
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}
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}
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else
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{
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/* This case we have O_TMPFILE, so our reference to it is via /proc/self/fd */
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char proc_fd_path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
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sprintf (proc_fd_path, "/proc/self/fd/%i", fd);
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if (replace)
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{
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/* In this case, we had our temp file atomically hidden, but now
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* we need to make it visible in the FS so we can do a rename.
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* Ideally, linkat() would gain AT_REPLACE or so.
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*/
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/* TODO - avoid double alloca, we can just alloca a copy of
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* the pathname plus space for tmp.XXXXX */
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char *dnbuf = strdupa (target);
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const char *dn = dirname (dnbuf);
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char *tmpname_buf = glnx_strjoina (dn, "/tmp.XXXXXX");
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guint count;
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const guint count_max = 100;
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for (count = 0; count < count_max; count++)
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{
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glnx_gen_temp_name (tmpname_buf);
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if (linkat (AT_FDCWD, proc_fd_path, target_dfd, tmpname_buf, AT_SYMLINK_FOLLOW) < 0)
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{
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if (errno == EEXIST)
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continue;
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else
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return glnx_throw_errno_prefix (error, "linkat");
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}
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else
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break;
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}
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if (count == count_max)
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{
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g_set_error (error, G_IO_ERROR, G_IO_ERROR_EXISTS,
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"Exhausted %u attempts to create temporary file", count);
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}
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if (renameat (target_dfd, tmpname_buf, target_dfd, target) < 0)
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{
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/* This is currently the only case where we need to have
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* a cleanup unlinkat() still with O_TMPFILE.
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*/
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int errsv = errno;
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(void) unlinkat (target_dfd, tmpname_buf, 0);
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errno = errsv;
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return glnx_throw_errno_prefix (error, "renameat");
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}
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}
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else
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{
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if (linkat (AT_FDCWD, proc_fd_path, target_dfd, target, AT_SYMLINK_FOLLOW) < 0)
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{
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if (errno == EEXIST && mode == GLNX_LINK_TMPFILE_NOREPLACE_IGNORE_EXIST)
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;
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else
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return glnx_throw_errno_prefix (error, "linkat");
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}
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}
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}
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return TRUE;
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}
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static guint8*
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glnx_fd_readall_malloc (int fd,
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gsize *out_len,
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gboolean nul_terminate,
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GCancellable *cancellable,
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GError **error)
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{
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const guint maxreadlen = 4096;
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struct stat stbuf;
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if (TEMP_FAILURE_RETRY (fstat (fd, &stbuf)) < 0)
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return glnx_null_throw_errno (error);
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gsize buf_allocated;
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if (S_ISREG (stbuf.st_mode) && stbuf.st_size > 0)
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buf_allocated = stbuf.st_size;
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else
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buf_allocated = 16;
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g_autofree guint8* buf = g_malloc (buf_allocated);
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gsize buf_size = 0;
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while (TRUE)
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{
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gsize readlen = MIN (buf_allocated - buf_size, maxreadlen);
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if (g_cancellable_set_error_if_cancelled (cancellable, error))
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return FALSE;
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gssize bytes_read;
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do
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bytes_read = read (fd, buf + buf_size, readlen);
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while (G_UNLIKELY (bytes_read == -1 && errno == EINTR));
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if (G_UNLIKELY (bytes_read == -1))
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return glnx_null_throw_errno (error);
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if (bytes_read == 0)
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break;
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buf_size += bytes_read;
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if (buf_allocated - buf_size < maxreadlen)
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buf = g_realloc (buf, buf_allocated *= 2);
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}
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if (nul_terminate)
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{
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if (buf_allocated - buf_size == 0)
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buf = g_realloc (buf, buf_allocated + 1);
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buf[buf_size] = '\0';
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}
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*out_len = buf_size;
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return g_steal_pointer (&buf);
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}
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/**
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* glnx_fd_readall_bytes:
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* @fd: A file descriptor
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* @cancellable: Cancellable:
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* @error: Error
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*
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* Read all data from file descriptor @fd into a #GBytes. It's
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* recommended to only use this for small files.
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*
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* Returns: (transfer full): A newly allocated #GBytes
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*/
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GBytes *
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glnx_fd_readall_bytes (int fd,
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GCancellable *cancellable,
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GError **error)
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{
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gsize len;
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guint8 *buf = glnx_fd_readall_malloc (fd, &len, FALSE, cancellable, error);
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if (!buf)
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return NULL;
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return g_bytes_new_take (buf, len);
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}
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/**
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* glnx_fd_readall_utf8:
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* @fd: A file descriptor
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* @out_len: (out): Returned length
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* @cancellable: Cancellable:
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* @error: Error
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*
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* Read all data from file descriptor @fd, validating
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* the result as UTF-8.
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*
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* Returns: (transfer full): A string validated as UTF-8, or %NULL on error.
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*/
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char *
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glnx_fd_readall_utf8 (int fd,
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gsize *out_len,
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GCancellable *cancellable,
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GError **error)
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{
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gsize len;
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g_autofree guint8 *buf = glnx_fd_readall_malloc (fd, &len, TRUE, cancellable, error);
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if (!buf)
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return FALSE;
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if (!g_utf8_validate ((char*)buf, len, NULL))
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{
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g_set_error (error,
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G_IO_ERROR,
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G_IO_ERROR_INVALID_DATA,
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"Invalid UTF-8");
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return FALSE;
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}
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if (out_len)
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*out_len = len;
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return (char*)g_steal_pointer (&buf);
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}
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/**
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* glnx_file_get_contents_utf8_at:
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* @dfd: Directory file descriptor
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* @subpath: Path relative to @dfd
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* @out_len: (out) (allow-none): Optional length
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* @cancellable: Cancellable
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* @error: Error
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*
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* Read the entire contents of the file referred
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* to by @dfd and @subpath, validate the result as UTF-8.
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* The length is optionally stored in @out_len.
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*
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* Returns: (transfer full): UTF-8 validated text, or %NULL on error
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*/
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char *
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glnx_file_get_contents_utf8_at (int dfd,
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const char *subpath,
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gsize *out_len,
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GCancellable *cancellable,
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GError **error)
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{
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dfd = glnx_dirfd_canonicalize (dfd);
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glnx_fd_close int fd = TEMP_FAILURE_RETRY (openat (dfd, subpath, O_RDONLY | O_NOCTTY | O_CLOEXEC));
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if (G_UNLIKELY (fd == -1))
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return glnx_null_throw_errno_prefix (error, "open(%s)", subpath);
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gsize len;
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g_autofree char *buf = glnx_fd_readall_utf8 (fd, &len, cancellable, error);
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if (G_UNLIKELY(!buf))
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return FALSE;
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if (out_len)
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*out_len = len;
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return g_steal_pointer (&buf);
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}
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/**
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* glnx_readlinkat_malloc:
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* @dfd: Directory file descriptor
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* @subpath: Subpath
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* @cancellable: Cancellable
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* @error: Error
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*
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* Read the value of a symlink into a dynamically
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* allocated buffer.
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*/
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char *
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glnx_readlinkat_malloc (int dfd,
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const char *subpath,
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GCancellable *cancellable,
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GError **error)
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{
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size_t l = 100;
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dfd = glnx_dirfd_canonicalize (dfd);
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for (;;)
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{
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g_autofree char *c = NULL;
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ssize_t n;
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c = g_malloc (l);
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n = TEMP_FAILURE_RETRY (readlinkat (dfd, subpath, c, l-1));
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if (n < 0)
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return glnx_null_throw_errno (error);
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if ((size_t) n < l-1)
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{
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c[n] = 0;
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return g_steal_pointer (&c);
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}
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l *= 2;
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}
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g_assert_not_reached ();
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}
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static gboolean
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copy_symlink_at (int src_dfd,
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const char *src_subpath,
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const struct stat *src_stbuf,
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int dest_dfd,
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const char *dest_subpath,
|
||
GLnxFileCopyFlags copyflags,
|
||
GCancellable *cancellable,
|
||
GError **error)
|
||
{
|
||
g_autofree char *buf = glnx_readlinkat_malloc (src_dfd, src_subpath, cancellable, error);
|
||
if (!buf)
|
||
return FALSE;
|
||
|
||
if (TEMP_FAILURE_RETRY (symlinkat (buf, dest_dfd, dest_subpath)) != 0)
|
||
return glnx_throw_errno_prefix (error, "symlinkat");
|
||
|
||
if (!(copyflags & GLNX_FILE_COPY_NOXATTRS))
|
||
{
|
||
g_autoptr(GVariant) xattrs = NULL;
|
||
|
||
if (!glnx_dfd_name_get_all_xattrs (src_dfd, src_subpath, &xattrs,
|
||
cancellable, error))
|
||
return FALSE;
|
||
|
||
if (!glnx_dfd_name_set_all_xattrs (dest_dfd, dest_subpath, xattrs,
|
||
cancellable, error))
|
||
return FALSE;
|
||
}
|
||
|
||
if (TEMP_FAILURE_RETRY (fchownat (dest_dfd, dest_subpath,
|
||
src_stbuf->st_uid, src_stbuf->st_gid,
|
||
AT_SYMLINK_NOFOLLOW)) != 0)
|
||
return glnx_throw_errno (error);
|
||
|
||
return TRUE;
|
||
}
|
||
|
||
#define COPY_BUFFER_SIZE (16*1024)
|
||
|
||
/* Most of the code below is from systemd, but has been reindented to GNU style,
|
||
* and changed to use POSIX error conventions (return -1, set errno) to more
|
||
* conveniently fit in with the rest of libglnx.
|
||
*/
|
||
|
||
static int btrfs_reflink(int infd, int outfd) {
|
||
g_return_val_if_fail(infd >= 0, -1);
|
||
g_return_val_if_fail(outfd >= 0, -1);
|
||
|
||
return ioctl (outfd, BTRFS_IOC_CLONE, infd);
|
||
}
|
||
|
||
/* Like write(), but loop until @nbytes are written, or an error
|
||
* occurs.
|
||
*
|
||
* On error, -1 is returned an @errno is set. NOTE: This is an
|
||
* API change from previous versions of this function.
|
||
*/
|
||
int
|
||
glnx_loop_write(int fd, const void *buf, size_t nbytes)
|
||
{
|
||
const uint8_t *p = buf;
|
||
|
||
g_return_val_if_fail(fd >= 0, -1);
|
||
g_return_val_if_fail(buf, -1);
|
||
|
||
errno = 0;
|
||
|
||
while (nbytes > 0)
|
||
{
|
||
ssize_t k;
|
||
|
||
k = write(fd, p, nbytes);
|
||
if (k < 0)
|
||
{
|
||
if (errno == EINTR)
|
||
continue;
|
||
|
||
return -1;
|
||
}
|
||
|
||
if (k == 0) /* Can't really happen */
|
||
{
|
||
errno = EIO;
|
||
return -1;
|
||
}
|
||
|
||
p += k;
|
||
nbytes -= k;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Read from @fdf until EOF, writing to @fdt. If @try_reflink is %TRUE,
|
||
* attempt to use any "reflink" functionality; see e.g. https://lwn.net/Articles/331808/
|
||
*
|
||
* The file descriptor @fdf must refer to a regular file.
|
||
*
|
||
* If provided, @max_bytes specifies the maximum number of bytes to read from @fdf.
|
||
* On error, this function returns `-1` and @errno will be set.
|
||
*/
|
||
int
|
||
glnx_regfile_copy_bytes (int fdf, int fdt, off_t max_bytes, gboolean try_reflink)
|
||
{
|
||
bool try_sendfile = true;
|
||
int r;
|
||
|
||
g_return_val_if_fail (fdf >= 0, -1);
|
||
g_return_val_if_fail (fdt >= 0, -1);
|
||
g_return_val_if_fail (max_bytes >= -1, -1);
|
||
|
||
/* Try btrfs reflinks first. */
|
||
if (try_reflink && max_bytes == (off_t) -1)
|
||
{
|
||
r = btrfs_reflink(fdf, fdt);
|
||
if (r >= 0)
|
||
return 0;
|
||
/* Fall through */
|
||
}
|
||
|
||
while (TRUE)
|
||
{
|
||
size_t m = COPY_BUFFER_SIZE;
|
||
ssize_t n;
|
||
|
||
if (max_bytes != (off_t) -1)
|
||
{
|
||
if ((off_t) m > max_bytes)
|
||
m = (size_t) max_bytes;
|
||
}
|
||
|
||
/* First try sendfile(), unless we already tried */
|
||
if (try_sendfile)
|
||
{
|
||
n = sendfile (fdt, fdf, NULL, m);
|
||
if (n < 0)
|
||
{
|
||
if (errno != EINVAL && errno != ENOSYS)
|
||
return -1;
|
||
|
||
try_sendfile = false;
|
||
/* use fallback below */
|
||
}
|
||
else if (n == 0) /* EOF */
|
||
break;
|
||
else if (n > 0)
|
||
/* Succcess! */
|
||
goto next;
|
||
}
|
||
|
||
/* As a fallback just copy bits by hand */
|
||
{ char buf[m];
|
||
|
||
n = read (fdf, buf, m);
|
||
if (n < 0)
|
||
return -1;
|
||
if (n == 0) /* EOF */
|
||
break;
|
||
|
||
if (glnx_loop_write (fdt, buf, (size_t) n) < 0)
|
||
return -1;
|
||
}
|
||
|
||
next:
|
||
if (max_bytes != (off_t) -1)
|
||
{
|
||
g_assert(max_bytes >= n);
|
||
max_bytes -= n;
|
||
if (max_bytes == 0)
|
||
break;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/**
|
||
* glnx_file_copy_at:
|
||
* @src_dfd: Source directory fd
|
||
* @src_subpath: Subpath relative to @src_dfd
|
||
* @dest_dfd: Target directory fd
|
||
* @dest_subpath: Destination name
|
||
* @copyflags: Flags
|
||
* @cancellable: cancellable
|
||
* @error: Error
|
||
*
|
||
* Perform a full copy of the regular file or
|
||
* symbolic link from @src_subpath to @dest_subpath.
|
||
*
|
||
* If @src_subpath is anything other than a regular
|
||
* file or symbolic link, an error will be returned.
|
||
*/
|
||
gboolean
|
||
glnx_file_copy_at (int src_dfd,
|
||
const char *src_subpath,
|
||
struct stat *src_stbuf,
|
||
int dest_dfd,
|
||
const char *dest_subpath,
|
||
GLnxFileCopyFlags copyflags,
|
||
GCancellable *cancellable,
|
||
GError **error)
|
||
{
|
||
gboolean ret = FALSE;
|
||
int r;
|
||
int dest_open_flags;
|
||
struct timespec ts[2];
|
||
glnx_fd_close int src_fd = -1;
|
||
glnx_fd_close int dest_fd = -1;
|
||
struct stat local_stbuf;
|
||
|
||
if (g_cancellable_set_error_if_cancelled (cancellable, error))
|
||
goto out;
|
||
|
||
src_dfd = glnx_dirfd_canonicalize (src_dfd);
|
||
dest_dfd = glnx_dirfd_canonicalize (dest_dfd);
|
||
|
||
/* Automatically do stat() if no stat buffer was supplied */
|
||
if (!src_stbuf)
|
||
{
|
||
if (fstatat (src_dfd, src_subpath, &local_stbuf, AT_SYMLINK_NOFOLLOW) != 0)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
src_stbuf = &local_stbuf;
|
||
}
|
||
|
||
if (S_ISLNK (src_stbuf->st_mode))
|
||
{
|
||
return copy_symlink_at (src_dfd, src_subpath, src_stbuf,
|
||
dest_dfd, dest_subpath,
|
||
copyflags,
|
||
cancellable, error);
|
||
}
|
||
else if (!S_ISREG (src_stbuf->st_mode))
|
||
{
|
||
g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
|
||
"Cannot copy non-regular/non-symlink file: %s", src_subpath);
|
||
goto out;
|
||
}
|
||
|
||
src_fd = TEMP_FAILURE_RETRY (openat (src_dfd, src_subpath, O_RDONLY | O_CLOEXEC | O_NOCTTY | O_NOFOLLOW));
|
||
if (src_fd == -1)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
|
||
dest_open_flags = O_WRONLY | O_CREAT | O_CLOEXEC | O_NOCTTY;
|
||
if (!(copyflags & GLNX_FILE_COPY_OVERWRITE))
|
||
dest_open_flags |= O_EXCL;
|
||
else
|
||
dest_open_flags |= O_TRUNC;
|
||
|
||
dest_fd = TEMP_FAILURE_RETRY (openat (dest_dfd, dest_subpath, dest_open_flags, src_stbuf->st_mode));
|
||
if (dest_fd == -1)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
|
||
r = glnx_regfile_copy_bytes (src_fd, dest_fd, (off_t) -1, TRUE);
|
||
if (r < 0)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
|
||
if (fchown (dest_fd, src_stbuf->st_uid, src_stbuf->st_gid) != 0)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
|
||
if (fchmod (dest_fd, src_stbuf->st_mode & 07777) != 0)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
|
||
ts[0] = src_stbuf->st_atim;
|
||
ts[1] = src_stbuf->st_mtim;
|
||
(void) futimens (dest_fd, ts);
|
||
|
||
if (!(copyflags & GLNX_FILE_COPY_NOXATTRS))
|
||
{
|
||
g_autoptr(GVariant) xattrs = NULL;
|
||
|
||
if (!glnx_fd_get_all_xattrs (src_fd, &xattrs,
|
||
cancellable, error))
|
||
goto out;
|
||
|
||
if (!glnx_fd_set_all_xattrs (dest_fd, xattrs,
|
||
cancellable, error))
|
||
goto out;
|
||
}
|
||
|
||
if (copyflags & GLNX_FILE_COPY_DATASYNC)
|
||
{
|
||
if (fdatasync (dest_fd) < 0)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
}
|
||
|
||
r = close (dest_fd);
|
||
dest_fd = -1;
|
||
if (r < 0)
|
||
{
|
||
glnx_set_error_from_errno (error);
|
||
goto out;
|
||
}
|
||
|
||
ret = TRUE;
|
||
out:
|
||
if (!ret)
|
||
(void) unlinkat (dest_dfd, dest_subpath, 0);
|
||
return ret;
|
||
}
|
||
|
||
/**
|
||
* glnx_file_replace_contents_at:
|
||
* @dfd: Directory fd
|
||
* @subpath: Subpath
|
||
* @buf: (array len=len) (element-type guint8): File contents
|
||
* @len: Length (if `-1`, assume @buf is `NUL` terminated)
|
||
* @flags: Flags
|
||
* @cancellable: Cancellable
|
||
* @error: Error
|
||
*
|
||
* Create a new file, atomically replacing the contents of @subpath
|
||
* (relative to @dfd) with @buf. By default, if the file already
|
||
* existed, fdatasync() will be used before rename() to ensure stable
|
||
* contents. This and other behavior can be controlled via @flags.
|
||
*
|
||
* Note that no metadata from the existing file is preserved, such as
|
||
* uid/gid or extended attributes. The default mode will be `0666`,
|
||
* modified by umask.
|
||
*/
|
||
gboolean
|
||
glnx_file_replace_contents_at (int dfd,
|
||
const char *subpath,
|
||
const guint8 *buf,
|
||
gsize len,
|
||
GLnxFileReplaceFlags flags,
|
||
GCancellable *cancellable,
|
||
GError **error)
|
||
{
|
||
return glnx_file_replace_contents_with_perms_at (dfd, subpath, buf, len,
|
||
(mode_t) -1, (uid_t) -1, (gid_t) -1,
|
||
flags, cancellable, error);
|
||
}
|
||
|
||
/**
|
||
* glnx_file_replace_contents_with_perms_at:
|
||
* @dfd: Directory fd
|
||
* @subpath: Subpath
|
||
* @buf: (array len=len) (element-type guint8): File contents
|
||
* @len: Length (if `-1`, assume @buf is `NUL` terminated)
|
||
* @mode: File mode; if `-1`, use `0666 - umask`
|
||
* @flags: Flags
|
||
* @cancellable: Cancellable
|
||
* @error: Error
|
||
*
|
||
* Like glnx_file_replace_contents_at(), but also supports
|
||
* setting mode, and uid/gid.
|
||
*/
|
||
gboolean
|
||
glnx_file_replace_contents_with_perms_at (int dfd,
|
||
const char *subpath,
|
||
const guint8 *buf,
|
||
gsize len,
|
||
mode_t mode,
|
||
uid_t uid,
|
||
gid_t gid,
|
||
GLnxFileReplaceFlags flags,
|
||
GCancellable *cancellable,
|
||
GError **error)
|
||
{
|
||
int r;
|
||
char *dnbuf = strdupa (subpath);
|
||
const char *dn = dirname (dnbuf);
|
||
|
||
dfd = glnx_dirfd_canonicalize (dfd);
|
||
|
||
/* With O_TMPFILE we can't use umask, and we can't sanely query the
|
||
* umask...let's assume something relatively standard.
|
||
*/
|
||
if (mode == (mode_t) -1)
|
||
mode = 0644;
|
||
|
||
glnx_fd_close int fd = -1;
|
||
g_autofree char *tmpfile_path = NULL;
|
||
if (!glnx_open_tmpfile_linkable_at (dfd, dn, O_WRONLY | O_CLOEXEC,
|
||
&fd, &tmpfile_path,
|
||
error))
|
||
return FALSE;
|
||
|
||
if (len == -1)
|
||
len = strlen ((char*)buf);
|
||
|
||
/* Note that posix_fallocate does *not* set errno but returns it. */
|
||
if (len > 0)
|
||
{
|
||
r = posix_fallocate (fd, 0, len);
|
||
if (r != 0)
|
||
{
|
||
errno = r;
|
||
return glnx_throw_errno_prefix (error, "fallocate");
|
||
}
|
||
}
|
||
|
||
if (glnx_loop_write (fd, buf, len) < 0)
|
||
return glnx_throw_errno (error);
|
||
|
||
if (!(flags & GLNX_FILE_REPLACE_NODATASYNC))
|
||
{
|
||
struct stat stbuf;
|
||
gboolean do_sync;
|
||
|
||
if (fstatat (dfd, subpath, &stbuf, AT_SYMLINK_NOFOLLOW) != 0)
|
||
{
|
||
if (errno != ENOENT)
|
||
return glnx_throw_errno (error);
|
||
do_sync = (flags & GLNX_FILE_REPLACE_DATASYNC_NEW) > 0;
|
||
}
|
||
else
|
||
do_sync = TRUE;
|
||
|
||
if (do_sync)
|
||
{
|
||
if (fdatasync (fd) != 0)
|
||
return glnx_throw_errno_prefix (error, "fdatasync");
|
||
}
|
||
}
|
||
|
||
if (uid != (uid_t) -1)
|
||
{
|
||
if (fchown (fd, uid, gid) != 0)
|
||
return glnx_throw_errno (error);
|
||
}
|
||
|
||
if (fchmod (fd, mode) != 0)
|
||
return glnx_throw_errno (error);
|
||
|
||
if (!glnx_link_tmpfile_at (dfd, GLNX_LINK_TMPFILE_REPLACE,
|
||
fd, tmpfile_path, dfd, subpath, error))
|
||
return FALSE;
|
||
|
||
return TRUE;
|
||
}
|
||
|
||
/**
|
||
* glnx_stream_fstat:
|
||
* @stream: A stream containing a Unix file descriptor
|
||
* @stbuf: Memory location to write stat buffer
|
||
* @error:
|
||
*
|
||
* Some streams created via libgsystem are #GUnixInputStream; these do
|
||
* not support e.g. g_file_input_stream_query_info(). This function
|
||
* allows dropping to the raw unix fstat() call for these types of
|
||
* streams, while still conveniently wrapped with the normal GLib
|
||
* handling of @error.
|
||
*/
|
||
gboolean
|
||
glnx_stream_fstat (GFileDescriptorBased *stream,
|
||
struct stat *stbuf,
|
||
GError **error)
|
||
{
|
||
int fd = g_file_descriptor_based_get_fd (stream);
|
||
|
||
if (fstat (fd, stbuf) == -1)
|
||
return glnx_throw_errno_prefix (error, "fstat");
|
||
|
||
return TRUE;
|
||
}
|