Re: [libvirt] [PATCH] snapshot: avoid virsh crash with older servers

Commits 51082301, 16d7b39, and 521cc447 introduced support for 'virsh snapshot-list --from' when talking to a server older than 0.9.5, but broke support for plain 'virsh snapshot-list' for the same old server in the process. Because the code is not properly gated, we end up with a SIGSEGV during a strcmp with a NULL argument. * tools/virsh.c (cmdSnapshotList): Don't waste time on fallbacks when --from is not present. --- Caveat: I tested by manually setting ctl->useSnapshotOld=true in virsh.c, rather than actually loading an older libvirtd, but I'm confident that the results would be the same. tools/virsh.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/tools/virsh.c b/tools/virsh.c index abcfbff..0453b95 100644 --- a/tools/virsh.c +++ b/tools/virsh.c @@ -16740,10 +16740,10 @@ cmdSnapshotList(vshControl *ctl, const vshCmd *cmd) qsort(&names[0], actual, sizeof(char*), namesorter); - if (tree || ctl->useSnapshotOld) { + if (tree || (from&& ctl->useSnapshotOld)) { parents = vshCalloc(ctl, sizeof(char *), actual); for (i = (from&& !ctl->useSnapshotOld); i< actual; i++) { - if (ctl->useSnapshotOld&& STREQ(names[i], from)) { + if (from&& ctl->useSnapshotOld&& STREQ(names[i], from)) { start_index = i; continue; } @@ -16765,7 +16765,8 @@ cmdSnapshotList(vshControl *ctl, const vshCmd *cmd) char indentBuf[INDENT_BUFLEN]; for (i = 0 ; i< actual ; i++) { memset(indentBuf, '\0', sizeof(indentBuf)); - if (ctl->useSnapshotOld ? STREQ(names[i], from) : !parents[i]) + if ((from&& ctl->useSnapshotOld) ? STREQ(names[i], from) : + !parents[i]) cmdNodeListDevicesPrint(ctl, names, parents, @@ -16834,7 +16835,7 @@ cmdSnapshotList(vshControl *ctl, const vshCmd *cmd) } for (i = 0; i< actual; i++) { - if (ctl->useSnapshotOld&& + if (from&& ctl->useSnapshotOld&& (descendants ? !names[i] : STRNEQ_NULLABLE(parents[i], from))) continue;