Re: [libvirt] [PATCH] esx: Disable libcurl's use of signals to fix a segfault

On 29.09.2012 22:17, Matthias Bolte wrote: > 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 DNS lookups which might result > in libcurl getting stuck in a DNS lookup in the worst case. > > Reported by Benjamin Wang. > --- > > src/esx/esx_vi.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/src/esx/esx_vi.c b/src/esx/esx_vi.c > index 275b858..125eaee 100644 > --- a/src/esx/esx_vi.c > +++ b/src/esx/esx_vi.c > @@ -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, > I think this is safe; From the version 7.10 curl can still timeout on DNS lookup even with CURLOPT_NOSIGNAL set: http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTNOSIGNAL So ACK. Michal