search for: have_accept4

...5 @@ exit_status_to_nbd_error (int status, const char *cmd) */ int set_cloexec (int fd) { -#if defined SOCK_CLOEXEC && defined HAVE_MKOSTEMP && defined HAVE_PIPE2 +#if (defined SOCK_CLOEXEC && defined HAVE_MKOSTEMP && defined HAVE_PIPE2 && \ + defined HAVE_ACCEPT4) nbdkit_error ("prefer creating fds with CLOEXEC atomically set"); close (fd); errno = EBADF; return -1; #else -# if defined SOCK_CLOEXEC || defined HAVE_MKOSTEMP || defined HAVE_PIPE2 +# if (defined SOCK_CLOEXEC || defined HAVE_MKOSTEMP || defined HAVE_PIPE2 || \ + !def...

On Fri, Aug 02, 2019 at 02:26:11PM -0500, Eric Blake wrote: > Allow a plugin field to declare whether a parallel plugin can tolerate > windows where fds are not CLOEXEC, or must take precautions to avoid > leaking fds if the plugin may fork. For safety reasons, the flag > defaults to off, but many in-tree plugins can set it to on (most > commonly because they don't fork after

This is a major rewrite compared to my v1 series, where I've tried a lot harder to ensure that we still accommodate building on Haiku (although I have not actually yet fired up a Haiku VM to try it for myself). I also managed to make the sh plugin fully parallel, on capable platforms. See also my question on patch 10 on whether I've picked the best naming convention. Eric Blake (17):

...ckaddr (&data->addr, data->addrlen); handle_single_connection (data->sock, data->sock); @@ -299,12 +296,9 @@ accept_connection (int listen_sock) } thread_data->instance_num = instance_num++; - thread_data->addrlen = sizeof thread_data->addr; again: #ifdef HAVE_ACCEPT4 - thread_data->sock = accept4 (listen_sock, - &thread_data->addr, &thread_data->addrlen, - SOCK_CLOEXEC); + thread_data->sock = accept4 (listen_sock, NULL, NULL, SOCK_CLOEXEC); #else /* If we were fully parallel,...

...ff --git a/server/plugins.c b/server/plugins.c index 87daaf2..65f6817 100644 --- a/server/plugins.c +++ b/server/plugins.c @@ -71,7 +71,7 @@ plugin_thread_model (struct backend *b) #if !(defined SOCK_CLOEXEC && defined HAVE_MKOSTEMP && defined HAVE_PIPE2 && \ defined HAVE_ACCEPT4) if (thread_model > NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS) { - nbdkit_debug ("system lacks atomic CLOEXEC, serializing to avoid fd leaks"); + debug ("system lacks atomic CLOEXEC, serializing to avoid fd leaks"); thread_model = NBDKIT_THREAD_MODEL_SERIALIZE_...

...5b0 100644 --- a/server/plugins.c +++ b/server/plugins.c @@ -90,6 +90,15 @@ plugin_thread_model (struct backend *b) int thread_model = p->plugin._thread_model; int r; + /* For now, we leak fds on all platforms; once that is fixed, this + * restriction can be limited to only occur when !HAVE_ACCEPT4. + */ + if (p->plugin._thread_model > NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS && + p->plugin.fork_safe == 0) { + nbdkit_debug (".fork_safe not set, serializing to avoid fd leaks"); + thread_model = NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS; + } + if...

When I added .can_FOO caching in 1.16, I missed the case that the sh plugin itself was calling .can_flush twice in some situations (in order to default .can_fua). Then right after, I regressed it to call .can_zero twice (in order to default .can_fast_zero). I also missed that .thread_model could use better caching, because at the time, I did not add testsuite coverage. Fix that now. Eric Blake

The patches following do indeed allow you to compile nbdkit.exe, but it does not actually work yet. I'm posting this experimental series more as a work in progress and to get feedback. Note this does not require Windows itself to build or test. You can cross-compile it using mingw64-* packages on Fedora or Debian, and test it [spoiler alert: it fails] using Wine. Rich.