On Sat, May 25, 2019 at 03:30:18PM -0500, Eric Blake wrote:
On 5/25/19 3:22 PM, Eric Blake wrote:
On 5/25/19 1:33 PM, Richard W.M. Jones wrote:
I also made the code a bit more robust about closing the socket along error paths. --- generator/states-connect.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-)
assert (!h->sock); assert (h->argv); assert (h->argv[0]); - if (socketpair (AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, - sv) == -1) { + if (socketpair (AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0, sv) == -1) {
Is it any easier to keep SOCK_NONBLOCK here and then clear O_NONBLOCK in the child process? It may matter if we try to port to a system that lacks SOCK_CLOEXEC (SOCK_NONBLOCK and SOCK_CLOEXEC were added at the same time). But we can deal with portability when someone reports a problem. For now the patch looks fine.
Hmm. Your use of SOCK_CLOEXEC here made me look for other fds that we might inadvertently destroy or leak in a multi-threaded process that does fork/exec (or even if the program linking against libnbd does connect_command() in two separate threads on two different nbd objects). I found: lib/crypto.c: fp = fopen (pskfile, "r");
We need to use either fopen(pskfile, "re") (if libc is new-enough to support "e" for O_CLOEXEC) or raw open(O_CLOEXEC) + fdopen() instead.
Based on this I pushed: https://github.com/libguestfs/libnbd/commit/516113b955be557f234534ab28b641a1... I don't know if this will actually fail on old / non-supporting libc or if it will just get ignored? Also I pushed some APIs for URI support, based on the discussion of NBD URIs here: https://lists.debian.org/nbd/2019/05/msg00034.html Of course we can change / revert them if the final proposal is different. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/