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/*
* libdpkg - Debian packaging suite library routines
* atomic-file.c - atomic file helper functions
*
* Copyright © 2011-2014 Guillem Jover <guillem@debian.org>
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <compat.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <dpkg/i18n.h>
#include <dpkg/dpkg.h>
#include <dpkg/atomic-file.h>
#define ATOMIC_FILE_NEW_EXT "-new"
#define ATOMIC_FILE_OLD_EXT "-old"
struct atomic_file *
atomic_file_new(const char *filename, enum atomic_file_flags flags)
{
struct atomic_file *file;
file = m_malloc(sizeof(*file));
file->flags = flags;
file->fp = NULL;
file->name = m_strdup(filename);
file->name_new = str_fmt("%s%s", filename, ATOMIC_FILE_NEW_EXT);
return file;
}
void
atomic_file_open(struct atomic_file *file)
{
file->fp = fopen(file->name_new, "w");
if (file->fp == NULL)
ohshite(_("unable to create new file '%.250s'"),
file->name_new);
fchmod(fileno(file->fp), 0644);
push_cleanup(cu_closestream, ~ehflag_normaltidy, 1, file->fp);
}
void
atomic_file_sync(struct atomic_file *file)
{
if (ferror(file->fp))
ohshite(_("unable to write new file '%.250s'"), file->name_new);
if (fflush(file->fp))
ohshite(_("unable to flush new file '%.250s'"), file->name_new);
if (fsync(fileno(file->fp)))
ohshite(_("unable to sync new file '%.250s'"), file->name_new);
}
void
atomic_file_close(struct atomic_file *file)
{
pop_cleanup(ehflag_normaltidy); /* fopen */
if (fclose(file->fp))
ohshite(_("unable to close new file '%.250s'"), file->name_new);
}
static void
atomic_file_backup(struct atomic_file *file)
{
char *name_old;
name_old = str_fmt("%s%s", file->name, ATOMIC_FILE_OLD_EXT);
if (unlink(name_old) && errno != ENOENT)
ohshite(_("error removing old backup file '%s'"), name_old);
if (link(file->name, name_old) && errno != ENOENT)
ohshite(_("error creating new backup file '%s'"), name_old);
free(name_old);
}
void
atomic_file_remove(struct atomic_file *file)
{
if (unlink(file->name_new))
ohshite(_("cannot remove '%.250s'"), file->name_new);
if (unlink(file->name) && errno != ENOENT)
ohshite(_("cannot remove '%.250s'"), file->name);
}
void
atomic_file_commit(struct atomic_file *file)
{
if (file->flags & ATOMIC_FILE_BACKUP)
atomic_file_backup(file);
if (rename(file->name_new, file->name))
ohshite(_("error installing new file '%s'"), file->name);
}
void
atomic_file_free(struct atomic_file *file)
{
free(file->name_new);
free(file->name);
free(file);
}
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