| Message ID | 1386954633-28905-17-git-send-email-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 13.12.2013 um 18:10 hat Max Reitz geschrieben: > There is no problem in giving no filename; in this case, it has to be > specified through the "image" option. > > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > block/blkdebug.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/block/blkdebug.c b/block/blkdebug.c > index 0c800ae..fdfc6b0 100644 > --- a/block/blkdebug.c > +++ b/block/blkdebug.c > @@ -327,8 +327,10 @@ static void blkdebug_parse_filename(const char *filename, QDict *options, > /* Parse the blkdebug: prefix */ > if (!strstart(filename, "blkdebug:", &filename)) { > /* There was no prefix; therefore, all options have to be already > - present in the QDict (except for the filename) */ > - qdict_put(options, "x-image", qstring_from_str(filename)); > + present in the QDict; if a filename is given, pass it */ > + if (filename) { filename can't be NULL here: For a non-NULL input, strstart() doesn't return NULL, and for a NULL string it segfaults... I don't think we have the segfault case here, because calling bdrv_parse_filename() without having a filename in the first place is quite pointless. I suspect giving no filename has been working even before this patch. > + qdict_put(options, "x-image", qstring_from_str(filename)); > + } > return; > } Having a test case in the commit would show what your intention was (and that the implementation doesn't do that). Kevin
On 13.12.2013 21:43, Kevin Wolf wrote: > Am 13.12.2013 um 18:10 hat Max Reitz geschrieben: >> There is no problem in giving no filename; in this case, it has to be >> specified through the "image" option. >> >> Signed-off-by: Max Reitz <mreitz@redhat.com> >> --- >> block/blkdebug.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/block/blkdebug.c b/block/blkdebug.c >> index 0c800ae..fdfc6b0 100644 >> --- a/block/blkdebug.c >> +++ b/block/blkdebug.c >> @@ -327,8 +327,10 @@ static void blkdebug_parse_filename(const char *filename, QDict *options, >> /* Parse the blkdebug: prefix */ >> if (!strstart(filename, "blkdebug:", &filename)) { >> /* There was no prefix; therefore, all options have to be already >> - present in the QDict (except for the filename) */ >> - qdict_put(options, "x-image", qstring_from_str(filename)); >> + present in the QDict; if a filename is given, pass it */ >> + if (filename) { > filename can't be NULL here: For a non-NULL input, strstart() doesn't > return NULL, and for a NULL string it segfaults... > > I don't think we have the segfault case here, because calling > bdrv_parse_filename() without having a filename in the first place is > quite pointless. I suspect giving no filename has been working even > before this patch. Right; for NULL input, that function isn't even called ("if (drv->bdrv_parse_filename && filename)" in bdrv_file_open()). Max >> + qdict_put(options, "x-image", qstring_from_str(filename)); >> + } >> return; >> } > Having a test case in the commit would show what your intention was (and > that the implementation doesn't do that). > > Kevin
diff --git a/block/blkdebug.c b/block/blkdebug.c index 0c800ae..fdfc6b0 100644 --- a/block/blkdebug.c +++ b/block/blkdebug.c @@ -327,8 +327,10 @@ static void blkdebug_parse_filename(const char *filename, QDict *options, /* Parse the blkdebug: prefix */ if (!strstart(filename, "blkdebug:", &filename)) { /* There was no prefix; therefore, all options have to be already - present in the QDict (except for the filename) */ - qdict_put(options, "x-image", qstring_from_str(filename)); + present in the QDict; if a filename is given, pass it */ + if (filename) { + qdict_put(options, "x-image", qstring_from_str(filename)); + } return; }
There is no problem in giving no filename; in this case, it has to be specified through the "image" option. Signed-off-by: Max Reitz <mreitz@redhat.com> --- block/blkdebug.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)