Am 28.06.2016 um 12:37 hat Tomáš Golembiovský geschrieben: > This is an attempt to fix small bug 1596870. > > When creating new disk backed by remote file accessed via HTTPS and the > backing file has zero length, qemu-img terminates with uniformative > error message: > > qemu-img: disk.qcow2: CURL: Error opening file: > > While it may not make much sense to operate on empty file, other block > backends (e.g. raw backend for regular files) seem to allow it. This > patch fixes it for the curl backend. > > Signed-off-by: Tomáš Golembiovský <[email protected]> > --- > block/curl.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/block/curl.c b/block/curl.c > index da9f5e8..ee6c5ea 100644 > --- a/block/curl.c > +++ b/block/curl.c > @@ -675,11 +675,17 @@ static int curl_open(BlockDriverState *bs, QDict > *options, int flags, > curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s); > if (curl_easy_perform(state->curl)) > goto out; > - curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d); > - if (d) > - s->len = (size_t)d; > - else if(!s->len) > + if (curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, > &d)) { > goto out; > + } > + if (d < 0) { > + pstrcpy(state->errmsg, CURL_ERROR_SIZE, > + "Received invalid file length."); > + goto out; > + }
Actually, it seems that d == -1 means that there is no information about the file length, so maybe the error message could be a bit more precise. A possible problem with the patch is that curl changed its behaviour in version 7.19.4. Before this version, it used to return 0 for a missing length, so we can't distinguish these cases on older versions. It's probably more common not to have the file length than having a zero-length file. Do we care about older versions? Commit 8a8f584 suggests that we did three years ago, it added an #if for a feature added in 7.19.4. Not sure if we do any more. RHEL 6 seems to be new enough. But if we do care, I guess we could do a similar #if that enables your code for newer curl versions and keeps erroring out for older versions. Any opinions on whether we still care about curl versions that old? > + s->len = (size_t)d; > + > if ((!strncasecmp(s->url, "http://";, strlen("http://";)) > || !strncasecmp(s->url, "https://";, strlen("https://";))) > && !s->accept_range) { Kevin
