On 08/18/2015 05:10 PM, Max Reitz wrote: > Instead of returning a pointer to the filename, copy it into a buffer > specified by the caller. > > Signed-off-by: Max Reitz <mre...@redhat.com> > --- > block.c | 25 ++++++++++++++++++------- > include/block/block.h | 2 +- > monitor.c | 6 +++++- > 3 files changed, 24 insertions(+), 9 deletions(-)
Would it be better to just have bdrv_get_encrypted_filename() return a
g_malloc'd buffer, instead of making the caller do it? Then the buffer
can be g_strdup'd to the correct size, instead of over-allocating
PATH_MAX bytes when a smaller size will usually do.
>
> diff --git a/block.c b/block.c
> index d088ee0..41b0f85 100644
> --- a/block.c
> +++ b/block.c
> @@ -2760,10 +2760,13 @@ void bdrv_add_key(BlockDriverState *bs, const char
> *key, Error **errp)
> }
> } else {
> if (bdrv_key_required(bs)) {
> + char *enc_filename = g_malloc(PATH_MAX);
> + bdrv_get_encrypted_filename(bs, enc_filename, PATH_MAX);
> error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED,
> "'%s' (%s) is encrypted",
> bdrv_get_device_or_node_name(bs),
> - bdrv_get_encrypted_filename(bs));
> + enc_filename);
Should you assert(enc_filename) to prove we know we aren't calling
error_set("%s", NULL)? After all, bdrv_get_encrypted_filename() can
return NULL, but only if no encrypted name is available; while
bdrv_key_required() implies that an encrypted name is available.
> -const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
> +char *bdrv_get_encrypted_filename(BlockDriverState *bs, char *dest, size_t
> sz)
> {
> - if (bs->backing_hd && bs->backing_hd->encrypted)
> - return bs->backing_file;
> - else if (bs->encrypted)
> - return bs->filename;
> - else
> + if (sz > INT_MAX) {
> + sz = INT_MAX;
> + }
> +
> + if (bs->backing_hd && bs->backing_hd->encrypted) {
> + pstrcpy(dest, sz, bs->backing_file);
> + return dest;
Again, using g_strdup() here instead of making the caller pass in a
buffer might be nicer semantics (certainly fewer places that have to
pre-allocate g_malloc0(PATH_MAX) bytes).
> +++ b/monitor.c
> @@ -5292,10 +5292,14 @@ int monitor_read_bdrv_key_start(Monitor *mon,
> BlockDriverState *bs,
> BlockCompletionFunc *completion_cb,
> void *opaque)
> {
> + char *enc_filename;
> int err;
>
> + enc_filename = g_malloc(PATH_MAX);
> + bdrv_get_encrypted_filename(bs, enc_filename, PATH_MAX);
> monitor_printf(mon, "%s (%s) is encrypted.\n", bdrv_get_device_name(bs),
> - bdrv_get_encrypted_filename(bs));
> + enc_filename);
> + g_free(enc_filename);
And once again, an assert(enc_filename) might be nice to be sure we
aren't dealing with a NULL return.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature
