From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49270) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ctzOt-0008Dl-DT for qemu-devel@nongnu.org; Fri, 31 Mar 2017 12:27:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ctzOr-0004CL-W5 for qemu-devel@nongnu.org; Fri, 31 Mar 2017 12:27:47 -0400 Date: Fri, 31 Mar 2017 12:27:38 -0400 From: Jeff Cody Message-ID: <20170331162738.GB28870@localhost.localdomain> References: <20170331152730.12514-1-eblake@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170331152730.12514-1-eblake@redhat.com> Subject: Re: [Qemu-devel] [PATCH for-2.9] rbd: Fix regression in legacy key/values containing escaped : List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, armbru@redhat.com, Alexandru.Avadanii@enea.com, Josh Durgin , Kevin Wolf , Max Reitz On Fri, Mar 31, 2017 at 10:27:30AM -0500, Eric Blake wrote: > Commit c7cacb3 accidentally broke legacy key-value parsing through > pseudo-filename parsing of -drive file=rbd://..., for any key that > contains an escaped ':'. Such a key is surprisingly common, thanks > to mon_host specifying a 'host:port' string. The break happens > because passing things from QDict through QemuOpts back to another > QDict requires that we pack our parsed key/value pairs into a string, > and then reparse that string, but the intermediate string that we > created ("key1=value1:key2=value2") lost the \: escaping that was > present in the original, so that we could no longer see which : were > used as separators vs. those used as part of the original input. > > Fix it by collecting the key/value pairs through a QList, and > sending that list on a round trip through a JSON QString (as in > '["key1","value1","key2","value2"]') on its way through QemuOpts, > rather than hand-rolling our own string. Since the string is only > handled internally, this was faster than creating a full-blown > struct of '[{"key1":"value1"},{"key2":"value2"}]', and safer at > guaranteeing order compared to '{"key1":"value1","key2":"value2"}'. > > It would be nicer if we didn't have to round-trip through QemuOpts > in the first place, but that's a much bigger task for later. > > Reproducer: > ./x86_64-softmmu/qemu-system-x86_64 -nodefaults -nographic -qmp stdio \ > -drive 'file=rbd:volumes/volume-ea141b5c-cdb3-4765-910d-e7008b209a70'\ > ':id=compute:key=AQAVkvxXAAAAABAA9ZxWFYdRmV+DSwKr7BKKXg=='\ > ':auth_supported=cephx\;none:mon_host=192.168.1.2\:6789'\ > ',format=raw,if=none,id=drive-virtio-disk0,'\ > 'serial=ea141b5c-cdb3-4765-910d-e7008b209a70,cache=writeback' > > Even without an RBD setup, this serves a test of whether we get > the incorrect parser error of: > qemu-system-x86_64: -drive file=rbd:...cache=writeback: conf option 6789 has no value > or the correct behavior of hanging while trying to connect to > the requested mon_host of 192.168.1.2:6789. > > Reported-by: Alexandru Avadanii > Signed-off-by: Eric Blake > --- > block/rbd.c | 83 +++++++++++++++++++++++++++++++------------------------------ > 1 file changed, 42 insertions(+), 41 deletions(-) > > diff --git a/block/rbd.c b/block/rbd.c > index 498322b..fbdb131 100644 > --- a/block/rbd.c > +++ b/block/rbd.c > @@ -20,6 +20,7 @@ > #include "crypto/secret.h" > #include "qemu/cutils.h" > #include "qapi/qmp/qstring.h" > +#include "qapi/qmp/qjson.h" > > /* > * When specifying the image filename use: > @@ -135,18 +136,16 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options, > Error **errp) > { > const char *start; > - char *p, *buf, *keypairs; > + char *p, *buf; > + QList *keypairs = NULL; > char *found_str; > - size_t max_keypair_size; > > if (!strstart(filename, "rbd:", &start)) { > error_setg(errp, "File name must start with 'rbd:'"); > return; > } > > - max_keypair_size = strlen(start) + 1; > buf = g_strdup(start); > - keypairs = g_malloc0(max_keypair_size); > p = buf; > > found_str = qemu_rbd_next_tok(p, '/', &p); > @@ -194,33 +193,30 @@ static void qemu_rbd_parse_filename(const char *filename, QDict *options, > } else if (!strcmp(name, "id")) { > qdict_put(options, "user" , qstring_from_str(value)); > } else { > - /* FIXME: This is pretty ugly, and not the right way to do this. > - * These should be contained in a structure, and then > - * passed explicitly as individual key/value pairs to > - * rados. Consider this legacy code that needs to be > - * updated. */ > - char *tmp = g_malloc0(max_keypair_size); > - /* only use a delimiter if it is not the first keypair found */ > - /* These are sets of unknown key/value pairs we'll pass along > - * to ceph */ > - if (keypairs[0]) { > - snprintf(tmp, max_keypair_size, ":%s=%s", name, value); > - pstrcat(keypairs, max_keypair_size, tmp); > - } else { > - snprintf(keypairs, max_keypair_size, "%s=%s", name, value); > + /* > + * We pass these internally to qemu_rbd_set_keypairs(), so > + * we can get away with the simpler list of [ "key1", > + * "value1", "key2", "value2" ] rather than a raw dict > + * { "key1": "value1", "key2": "value2" } where we can't > + * guarantee order, or even a more correct but complex > + * [ { "key1": "value1" }, { "key2": "value2" } ] > + */ > + if (!keypairs) { > + keypairs = qlist_new(); > } > - g_free(tmp); > + qlist_append(keypairs, qstring_from_str(name)); > + qlist_append(keypairs, qstring_from_str(value)); > } > } > > - if (keypairs[0]) { > - qdict_put(options, "=keyvalue-pairs", qstring_from_str(keypairs)); > + if (keypairs) { > + qdict_put(options, "=keyvalue-pairs", > + qobject_to_json(QOBJECT(keypairs))); > } > > - > done: > g_free(buf); > - g_free(keypairs); > + QDECREF(keypairs); > return; > } > > @@ -244,36 +240,41 @@ static int qemu_rbd_set_auth(rados_t cluster, const char *secretid, > return 0; > } > > -static int qemu_rbd_set_keypairs(rados_t cluster, const char *keypairs, > +static int qemu_rbd_set_keypairs(rados_t cluster, const char *keypairs_json, > Error **errp) > { > - char *p, *buf; > - char *name; > - char *value; > + QList *keypairs; > + QString *name; > + QString *value; > + const char *key; > + size_t remaining; > int ret = 0; > > - buf = g_strdup(keypairs); > - p = buf; > + if (!keypairs_json) { > + return ret; > + } > + keypairs = qobject_to_qlist(qobject_from_json(keypairs_json, > + &error_abort)); > + remaining = qlist_size(keypairs) / 2; > + assert(remaining); > > - while (p) { > - name = qemu_rbd_next_tok(p, '=', &p); > - if (!p) { > - error_setg(errp, "conf option %s has no value", name); > - ret = -EINVAL; > - break; > - } > + while (remaining--) { > + name = qobject_to_qstring(qlist_pop(keypairs)); > + value = qobject_to_qstring(qlist_pop(keypairs)); > + assert(name && value); We could just drop 'remaining' and break if !name && !value, and then assert(!name || !value). But this is fine too, of course. Thanks for the fix: Reviewed-by: Jeff Cody > + key = qstring_get_str(name); > > - value = qemu_rbd_next_tok(p, ':', &p); > - > - ret = rados_conf_set(cluster, name, value); > + ret = rados_conf_set(cluster, key, qstring_get_str(value)); > + QDECREF(name); > + QDECREF(value); > if (ret < 0) { > - error_setg_errno(errp, -ret, "invalid conf option %s", name); > + error_setg_errno(errp, -ret, "invalid conf option %s", key); > ret = -EINVAL; > break; > } > } > > - g_free(buf); > + QDECREF(keypairs); > return ret; > } > > -- > 2.9.3 >