[Libguestfs] [RFC nbdkit PATCH] server: Allow --run with --vsock

Now that kernels support vsock loopback, we have no reason to forbid --vsock with --run. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- I'm hoping to commit something like this, but right now, the testsuite is failing more times than it succeeds, with: + port=1082294412 + nbdkit --vsock --port 1082294412 memory 1M --run 'sleep 1; nbdsh -u "$uri" -c "$check"' ... libnbd: debug: nbdsh: nbd_connect_uri: enter: uri="nbd+vsock://1:1082294412" libnbd: debug: nbdsh: nbd_connect_uri: event CmdConnectSockAddr: START -> CONNECT.START libnbd: debug: nbdsh: nbd_connect_uri: poll start: events=4 libnbd: debug: nbdsh: nbd_connect_uri: poll end: r=1 revents=c libnbd: debug: nbdsh: nbd_connect_uri: event NotifyWrite: CONNECT.START -> CONNECT.CONNECTING libnbd: debug: nbdsh: nbd_connect_uri: transition: CONNECT.CONNECTING -> DEAD libnbd: debug: nbdsh: nbd_connect_uri: leave: error="nbd_connect_uri: connect: Connection reset by peer" but when I try the same from the command line in isolation: $ ./nbdkit --vsock --port=12345 memory 1m --run 'nbdsh -u $uri -c "print(h.get_size())"' 1048576 I wonder if there is some sort of race where an existing vsock on a different port is interfering (since the test opens up a background server on one port before the one-liner attempt on a different port). docs/nbdkit-captive.pod | 3 ++- server/internal.h | 1 + server/captive.c | 46 +++++++++++++++++++++-------------------- server/main.c | 3 +-- tests/test-vsock.sh | 21 +++++++++++++------ 5 files changed, 43 insertions(+), 31 deletions(-) diff --git a/docs/nbdkit-captive.pod b/docs/nbdkit-captive.pod index 09628367..7f942f95 100644 --- a/docs/nbdkit-captive.pod +++ b/docs/nbdkit-captive.pod @@ -54,7 +54,8 @@ option to set the preferred export name, this is included in the URI. An older URL that refers to the nbdkit port or socket in a manner specific to certain tools. This form does not include an export name, -even if B<-e> was used. +even if B<-e> was used. This variable is empty when using vsock +loopback (when the B<--vsock> option is used, only C<$uri> is valid). Note there is some magic here, since qemu and guestfish URLs have a different format, so nbdkit tries to guess which you are running. If diff --git a/server/internal.h b/server/internal.h index 68c53366..1dd84ccb 100644 --- a/server/internal.h +++ b/server/internal.h @@ -129,6 +129,7 @@ extern bool tls_verify_peer; extern char *unixsocket; extern const char *user, *group; extern bool verbose; +extern bool vsock; extern int saved_stdin; extern int saved_stdout; diff --git a/server/captive.c b/server/captive.c index f8107604..a5b227c4 100644 --- a/server/captive.c +++ b/server/captive.c @@ -72,7 +72,7 @@ run_command (void) /* Construct $uri. */ fprintf (fp, "uri="); if (port) { - fprintf (fp, "nbd://localhost:"); + fprintf (fp, vsock ? "nbd+vsock://1:" : "nbd://localhost:"); shell_quote (port, fp); if (strcmp (exportname, "") != 0) { putc ('/', fp); @@ -99,29 +99,31 @@ run_command (void) * different syntax, so try to guess which one we need. */ fprintf (fp, "nbd="); - if (strstr (run, "guestfish")) { - if (port) { - fprintf (fp, "nbd://localhost:"); - shell_quote (port, fp); + if (!vsock) { + if (strstr (run, "guestfish")) { + if (port) { + fprintf (fp, "nbd://localhost:"); + shell_quote (port, fp); + } + else if (unixsocket) { + fprintf (fp, "nbd://\\?socket="); + shell_quote (unixsocket, fp); + } + else + abort (); } - else if (unixsocket) { - fprintf (fp, "nbd://\\?socket="); - shell_quote (unixsocket, fp); + else /* qemu */ { + if (port) { + fprintf (fp, "nbd:localhost:"); + shell_quote (port, fp); + } + else if (unixsocket) { + fprintf (fp, "nbd:unix:"); + shell_quote (unixsocket, fp); + } + else + abort (); } - else - abort (); - } - else /* qemu */ { - if (port) { - fprintf (fp, "nbd:localhost:"); - shell_quote (port, fp); - } - else if (unixsocket) { - fprintf (fp, "nbd:unix:"); - shell_quote (unixsocket, fp); - } - else - abort (); } putc ('\n', fp); diff --git a/server/main.c b/server/main.c index c432f5bd..dfa81a85 100644 --- a/server/main.c +++ b/server/main.c @@ -545,8 +545,7 @@ main (int argc, char *argv[]) (listen_stdin && run) || (listen_stdin && dump_plugin) || (vsock && unixsocket) || - (vsock && listen_stdin) || - (vsock && run)) { + (vsock && listen_stdin)) { fprintf (stderr, "%s: --dump-plugin, -p, --run, -s, -U or --vsock options " "cannot be used in this combination\n", diff --git a/tests/test-vsock.sh b/tests/test-vsock.sh index 54115e78..13c1c29d 100755 --- a/tests/test-vsock.sh +++ b/tests/test-vsock.sh @@ -57,16 +57,25 @@ files="vsock.pid" rm -f $files cleanup_fn rm -f $files -# Run nbdkit. -start_nbdkit -P vsock.pid --vsock --port $port memory 1M - -export port -nbdsh -c - <<'EOF' +# An nbdsh script for connecting to vsock +export connect=' import os # 1 = VMADDR_CID_LOCAL h.connect_vsock (1, int (os.environ["port"])) +' +export check=' size = h.get_size () assert size == 1048576 -EOF +' + +# Run nbdkit. +start_nbdkit -P vsock.pid --vsock --port $port memory 1M + +export port +nbdsh -c "$connect" -c "$check" + +# Repeat on a different port, testing interaction with --run +port=$((port + 1)) +nbdkit --vsock --port $port memory 1M --run 'nbdsh -u "$uri" -c "$check"' -- 2.27.0