diff options
Diffstat (limited to 'lib/dpkg/atomic-file.c')
| -rw-r--r-- | lib/dpkg/atomic-file.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/lib/dpkg/atomic-file.c b/lib/dpkg/atomic-file.c new file mode 100644 index 0000000..be7a33e --- /dev/null +++ b/lib/dpkg/atomic-file.c @@ -0,0 +1,132 @@ +/* + * 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/dir.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 && file->flags & ATOMIC_FILE_MKPATH) { + if (dir_make_path_parent(file->name, 0755) < 0) + ohshite(_("cannot create base directory for %s"), + file->name); + + 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); +} |