backups: take an unlikely condition into account

Between the first stat (that sets 'realexists') and the second stat
(directly after), the file might have disappeared, which would mean
that current_stat would be NULL.  Prevent dereferencing this further
down.
This commit is contained in:
Benno Schulenberg 2016-05-21 13:50:14 +02:00
parent 8bf5e58f37
commit f9fe9a7d57

View File

@ -1801,9 +1801,9 @@ bool write_file(const char *name, FILE *f_open, bool tmp, append_type
* aren't appending, prepending, or writing a selection, we backup
* only if the file has not been modified by someone else since nano
* opened it. */
if (ISSET(BACKUP_FILE) && !tmp && realexists && ((append != OVERWRITE ||
openfile->mark_set) || (openfile->current_stat &&
openfile->current_stat->st_mtime == st.st_mtime))) {
if (ISSET(BACKUP_FILE) && !tmp && realexists && openfile->current_stat &&
(append != OVERWRITE || openfile->mark_set ||
openfile->current_stat->st_mtime == st.st_mtime)) {
int backup_fd;
FILE *backup_file;
char *backupname;