tweaks: move the backup code to a separate function
This change moves the code responsible for backup creation to a new, separate function, backup_file(). This function returns a boolean indicating whether saving the buffer should proceed or not. Signed-off-by: Michalis Kokologiannakis <michalis@mpi-sws.org>master
Michalis Kokologiannakis
Benno Schulenberg
parent
62ffc221aa
commit
ed76a045ae
308
src/files.c
308
src/files.c
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@ -1588,6 +1588,165 @@ int sync_file(FILE *thefile)
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return 0;
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return 0;
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}
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}
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#ifndef NANO_TINY
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/* Create a backup of an existing file. If the user did not request backups,
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* make a temporary one (trying first in the directory of the original file,
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* then in the user's home directory). Return TRUE if the save can proceed. */
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bool backup_file(char *realname, char **backupname)
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{
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bool second_attempt = FALSE;
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/* Whether a normal backup failed and we are resorting to a failsafe. */
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static struct timespec filetime[2];
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int backup_cflags, backup_fd, verdict;
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FILE *original = NULL, *backup_file = NULL;
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/* Remember the original file's access and modification times. */
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filetime[0].tv_sec = openfile->statinfo->st_atime;
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filetime[1].tv_sec = openfile->statinfo->st_mtime;
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statusbar(_("Making backup..."));
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/* If no backup directory was specified, we make a simple backup
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* by appending a tilde to the original file name. Otherwise,
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* we create a numbered backup in the specified directory. */
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if (!ISSET(MAKE_BACKUP)) {
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*backupname = charalloc(strlen(realname) + 8);
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sprintf(*backupname, "%s~XXXXXX", realname);
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backup_fd = mkstemp(*backupname);
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goto try_backup;
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} else if (backup_dir == NULL) {
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*backupname = charalloc(strlen(realname) + 2);
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sprintf(*backupname, "%s~", realname);
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} else {
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char *backuptemp = get_full_path(realname);
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/* If we have a valid absolute path, replace each slash
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* in this full path with an exclamation mark. Otherwise,
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* just use the file-name portion of the given path. */
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if (backuptemp) {
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for (int i = 0; backuptemp[i] != '\0'; i++)
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if (backuptemp[i] == '/')
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backuptemp[i] = '!';
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} else
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backuptemp = copy_of(tail(realname));
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*backupname = charalloc(strlen(backup_dir) + strlen(backuptemp) + 1);
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sprintf(*backupname, "%s%s", backup_dir, backuptemp);
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free(backuptemp);
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backuptemp = get_next_filename(*backupname, "~");
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free(*backupname);
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*backupname = backuptemp;
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/* If all numbered backup names are taken, the user must
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* be fond of backups. Thus, without one, do not go on. */
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if (**backupname == '\0') {
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statusline(ALERT, _("Too many existing backup files"));
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return FALSE;
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}
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}
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/* Now first try to delete an existing backup file. */
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if (unlink(*backupname) < 0 && errno != ENOENT && !ISSET(INSECURE_BACKUP))
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goto backup_error;
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if (ISSET(INSECURE_BACKUP))
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backup_cflags = O_WRONLY | O_CREAT | O_TRUNC;
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else
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backup_cflags = O_WRONLY | O_CREAT | O_EXCL;
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/* Create the backup file (or truncate the existing one). */
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backup_fd = open(*backupname, backup_cflags, S_IRUSR|S_IWUSR);
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try_backup:
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if (backup_fd >= 0)
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backup_file = fdopen(backup_fd, "wb");
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if (backup_file == NULL)
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goto backup_error;
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/* Try to change owner and group to those of the original file;
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* ignore errors, as a normal user cannot change the owner. */
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IGNORE_CALL_RESULT(fchown(backup_fd, openfile->statinfo->st_uid,
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openfile->statinfo->st_gid));
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/* Set the backup's permissions to those of the original file.
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* It is not a security issue if this fails, as we have created
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* the file with just read and write permission for the owner. */
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IGNORE_CALL_RESULT(fchmod(backup_fd, openfile->statinfo->st_mode));
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original = fopen(realname, "rb");
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/* If we can't read from the original file, go on, since saving
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* only the current buffer is better than saving nothing. */
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if (original == NULL) {
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statusline(ALERT, _("Error reading %s: %s"), realname, strerror(errno));
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fclose(backup_file);
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return TRUE;
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}
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/* Copy the existing file to the backup. */
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verdict = copy_file(original, backup_file, FALSE);
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if (verdict < 0) {
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fclose(backup_file);
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statusline(ALERT, _("Error reading %s: %s"), realname, strerror(errno));
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return FALSE;
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} else if (verdict > 0) {
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fclose(backup_file);
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goto backup_error;
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}
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/* Since this backup is a newly created file, explicitly sync it to
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* permanent storage before starting to write out the actual file. */
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if (sync_file(backup_file) != 0)
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goto backup_error;
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/* Set the backup's timestamps to those of the original file.
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* Failure is unimportant: saving the file apparently worked. */
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IGNORE_CALL_RESULT(futimens(backup_fd, filetime));
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if (fclose(backup_file) == 0)
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return TRUE;
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backup_error:
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get_homedir();
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/* If the first attempt of copying the file failed, try again to HOME. */
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if (!second_attempt && homedir) {
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unlink(*backupname);
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free(*backupname);
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*backupname = charalloc(strlen(homedir) + strlen(tail(realname)) + 9);
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sprintf(*backupname, "%s/%s~XXXXXX", homedir, tail(realname));
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backup_fd = mkstemp(*backupname);
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backup_file = NULL;
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if (ISSET(MAKE_BACKUP)) {
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warn_and_briefly_pause(_("Cannot make regular backup"));
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warn_and_briefly_pause(_("Trying again in your home directory"));
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currmenu = MMOST;
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}
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second_attempt = TRUE;
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goto try_backup;
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}
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/* If all attempts failed, notify the user, because if something goes
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* wrong during the save, the contents of the file might be lost. */
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warn_and_briefly_pause(_("Cannot make backup"));
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if (!user_wants_to_proceed()) {
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statusline(HUSH, _("Cannot write backup %s: %s"),
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*backupname, strerror(errno));
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return FALSE;
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}
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return TRUE;
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}
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#endif /* !NANO_TINY */
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/* Write the current buffer to disk. If thefile isn't NULL, we write to a
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/* Write the current buffer to disk. If thefile isn't NULL, we write to a
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* temporary file that is already open. If tmp is TRUE (when spell checking
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* temporary file that is already open. If tmp is TRUE (when spell checking
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* or emergency dumping, for example), we set the umask to disallow anyone else
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* or emergency dumping, for example), we set the umask to disallow anyone else
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@ -1606,8 +1765,6 @@ bool write_file(const char *name, FILE *thefile, bool tmp,
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/* The status fields filled in by statting the file. */
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/* The status fields filled in by statting the file. */
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char *backupname = NULL;
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char *backupname = NULL;
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/* The name of the backup file, in case we make one. */
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/* The name of the backup file, in case we make one. */
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bool second_attempt = FALSE;
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/* Whether a normal backup failed and we are resorting to a failsafe. */
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#endif
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#endif
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char *realname = real_dir_from_tilde(name);
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char *realname = real_dir_from_tilde(name);
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/* The filename after tilde expansion. */
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/* The filename after tilde expansion. */
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@ -1644,155 +1801,10 @@ bool write_file(const char *name, FILE *thefile, bool tmp,
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if (is_existing_file && openfile->statinfo &&
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if (is_existing_file && openfile->statinfo &&
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(openfile->statinfo->st_mtime == st.st_mtime ||
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(openfile->statinfo->st_mtime == st.st_mtime ||
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method != OVERWRITE || openfile->mark)) {
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method != OVERWRITE || openfile->mark)) {
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static struct timespec filetime[2];
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if (!backup_file(realname, &backupname))
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int backup_cflags, backup_fd, verdict;
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FILE *original = NULL, *backup_file = NULL;
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/* Remember the original file's access and modification times. */
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filetime[0].tv_sec = openfile->statinfo->st_atime;
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filetime[1].tv_sec = openfile->statinfo->st_mtime;
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statusbar(_("Making backup..."));
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/* If no backup directory was specified, we make a simple backup
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* by appending a tilde to the original file name. Otherwise,
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* we create a numbered backup in the specified directory. */
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if (!ISSET(MAKE_BACKUP)) {
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backupname = charalloc(strlen(realname) + 8);
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sprintf(backupname, "%s~XXXXXX", realname);
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backup_fd = mkstemp(backupname);
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goto try_backup;
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} else if (backup_dir == NULL) {
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backupname = charalloc(strlen(realname) + 2);
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sprintf(backupname, "%s~", realname);
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} else {
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char *backuptemp = get_full_path(realname);
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/* If we have a valid absolute path, replace each slash
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* in this full path with an exclamation mark. Otherwise,
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* just use the file-name portion of the given path. */
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if (backuptemp) {
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for (int i = 0; backuptemp[i] != '\0'; i++)
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if (backuptemp[i] == '/')
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backuptemp[i] = '!';
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} else
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backuptemp = copy_of(tail(realname));
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backupname = charalloc(strlen(backup_dir) + strlen(backuptemp) + 1);
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sprintf(backupname, "%s%s", backup_dir, backuptemp);
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free(backuptemp);
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backuptemp = get_next_filename(backupname, "~");
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free(backupname);
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backupname = backuptemp;
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/* If all numbered backup names are taken, the user must
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* be fond of backups. Thus, without one, do not go on. */
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if (*backupname == '\0') {
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statusline(ALERT, _("Too many existing backup files"));
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goto cleanup_and_exit;
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goto cleanup_and_exit;
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}
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}
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}
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/* Now first try to delete an existing backup file. */
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if (unlink(backupname) < 0 && errno != ENOENT && !ISSET(INSECURE_BACKUP))
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goto backup_error;
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if (ISSET(INSECURE_BACKUP))
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backup_cflags = O_WRONLY | O_CREAT | O_TRUNC;
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else
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backup_cflags = O_WRONLY | O_CREAT | O_EXCL;
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/* Create the backup file (or truncate the existing one). */
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backup_fd = open(backupname, backup_cflags, S_IRUSR|S_IWUSR);
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try_backup:
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if (backup_fd >= 0)
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backup_file = fdopen(backup_fd, "wb");
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if (backup_file == NULL)
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goto backup_error;
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/* Try to change owner and group to those of the original file;
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* ignore errors, as a normal user cannot change the owner. */
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IGNORE_CALL_RESULT(fchown(backup_fd, openfile->statinfo->st_uid,
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openfile->statinfo->st_gid));
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/* Set the backup's permissions to those of the original file.
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* It is not a security issue if this fails, as we have created
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* the file with just read and write permission for the owner. */
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IGNORE_CALL_RESULT(fchmod(backup_fd, openfile->statinfo->st_mode));
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original = fopen(realname, "rb");
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/* If we can't read from the original file, go on, since saving
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* only the current buffer is better than saving nothing. */
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if (original == NULL) {
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statusline(ALERT, _("Error reading %s: %s"), realname, strerror(errno));
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fclose(backup_file);
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goto save_the_file;
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}
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/* Copy the existing file to the backup. */
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verdict = copy_file(original, backup_file, FALSE);
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if (verdict < 0) {
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fclose(backup_file);
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statusline(ALERT, _("Error reading %s: %s"), realname, strerror(errno));
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goto cleanup_and_exit;
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} else if (verdict > 0) {
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fclose(backup_file);
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goto backup_error;
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}
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/* Since this backup is a newly created file, explicitly sync it to
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* permanent storage before starting to write out the actual file. */
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if (sync_file(backup_file) != 0)
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goto backup_error;
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/* Set the backup's timestamps to those of the original file.
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* Failure is unimportant: saving the file apparently worked. */
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IGNORE_CALL_RESULT(futimens(backup_fd, filetime));
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if (fclose(backup_file) == 0)
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goto save_the_file;
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backup_error:
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get_homedir();
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/* If the first attempt of copying the file failed, try again to HOME. */
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if (!second_attempt && homedir) {
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unlink(backupname);
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free(backupname);
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backupname = charalloc(strlen(homedir) + strlen(tail(realname)) + 9);
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sprintf(backupname, "%s/%s~XXXXXX", homedir, tail(realname));
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backup_fd = mkstemp(backupname);
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backup_file = NULL;
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if (ISSET(MAKE_BACKUP)) {
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warn_and_briefly_pause(_("Cannot make regular backup"));
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warn_and_briefly_pause(_("Trying again in your home directory"));
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currmenu = MMOST;
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}
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second_attempt = TRUE;
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goto try_backup;
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}
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/* If all attempts failed, notify the user, because if something goes
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* wrong during the save, the contents of the file might be lost. */
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warn_and_briefly_pause(_("Cannot make backup"));
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if (!user_wants_to_proceed()) {
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statusline(HUSH, _("Cannot write backup %s: %s"),
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backupname, strerror(errno));
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goto cleanup_and_exit;
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}
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}
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save_the_file:
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/* When prepending, first copy the existing file to a temporary file. */
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/* When prepending, first copy the existing file to a temporary file. */
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if (method == PREPEND) {
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if (method == PREPEND) {
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FILE *source = fopen(realname, "rb");
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FILE *source = fopen(realname, "rb");
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