esx: Disable libcurl's use of signals to fix a segfault

libcurl uses a SIGALRM in combination with sigsetjmp/siglongjmp to be
able to abort a DNS lookup when it takes too long. The problem with this
in a multi-threaded application is that the signal handler for SIGALRM
and the call to siglongjmp can be executed on a thread that is different
from the one that initially did the SIGALRM setup and the call to
sigsetjmp. In the reported case this triggered a segfault.

Disable libcurl's use of signals to avoid this situation. This has the
disadvantage of losing the ability to abort synchronous DNS lookups which
might result in libcurl getting stuck in a DNS lookup in the worst case.
When libcurl was build with an asynchronous DNS backend such as c-ares
then there is no problem because the timeout mechanism works without
signals here anyway.

Reported by Benjamin Wang.
This commit is contained in:
Matthias Bolte 2012-09-29 22:16:30 +02:00
parent 4bdc8606e6
commit 0821ea6b3c

View File

@ -330,6 +330,7 @@ esxVI_CURL_Connect(esxVI_CURL *curl, esxUtil_ParsedUri *parsedUri)
}
curl_easy_setopt(curl->handle, CURLOPT_USERAGENT, "libvirt-esx");
curl_easy_setopt(curl->handle, CURLOPT_NOSIGNAL, 1);
curl_easy_setopt(curl->handle, CURLOPT_HEADER, 0);
curl_easy_setopt(curl->handle, CURLOPT_FOLLOWLOCATION, 0);
curl_easy_setopt(curl->handle, CURLOPT_SSL_VERIFYPEER,