> On Dec 7, 2017, at 4:12 PM, Ben Pfaff <[email protected]> wrote:
>
> diff --git a/ovsdb/log.c b/ovsdb/log.c
> index 380f5e93d464..e6f66e668fe5 100644
> --- a/ovsdb/log.c
> +++ b/ovsdb/log.c
> ...
> @@ -53,12 +54,17 @@ struct ovsdb_log {
> * the new log into '*filep' and returns NULL; otherwise returns NULL and
> * stores NULL into '*filep'.
> *
> + * 'magic' is a short text string put at the beginning of every record and
> used
> + * to distinguish one kind of log file from another. For a conventional
> OVSDB
> + * log file, use OVSDB_MAGIC.
Since 'magic' is a string, it might be good to be explicit that "OVSDB_MAGIC"
is a #define.
> struct ovsdb_error *
> -ovsdb_log_open(const char *name, enum ovsdb_log_open_mode open_mode,
> +ovsdb_log_open(const char *name, const char *magic,
> + enum ovsdb_log_open_mode open_mode,
> int locking, struct ovsdb_log **filep)
> {
> struct lockfile *lockfile;
> @@ -118,10 +124,30 @@ ovsdb_log_open(const char *name, enum
> ovsdb_log_open_mode open_mode,
> goto error_unlock;
> }
>
> + if (!fstat(fd, &s)) {
> + if (s.st_size == 0) {
> + /* It's (probably) a new file so fsync() its parent directory to
> + * ensure that its directory entry is committed to disk. */
> + fsync_parent_dir(name);
> + } else if (s.st_size >= strlen(magic) && S_ISREG(s.st_mode)) {
> + /* Try to read the magic from the first log record. If it's not
> + * the magic we expect, this is the wrong kind of file, so reject
> + * it immediately. */
> + size_t magic_len = strlen(magic);
> + char *buf = xzalloc(magic_len + 1);
> + bool err = (read(fd, buf, magic_len) == magic_len
> + && strcmp(buf, magic));
It's probably hard to do much about it at this point, but if the new magic is a
substring of existing one (e.g., just "OVSDB"), then this will not catch it.
Probably not a big deal in practice, though.
> @@ -132,6 +158,7 @@ ovsdb_log_open(const char *name, enum ovsdb_log_open_mode
> open_mode,
>
> file = xmalloc(sizeof *file);
> file->name = xstrdup(name);
> + file->magic = xstrdup(magic);
I don't think this gets freed.
Acked-by: Justin Pettit <[email protected]>
--Justin
_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
