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[Qemu-devel] [PULL 7/9] sockets: allow SocketAddress 'fd' to reference n
From: |
Daniel P . Berrangé |
Subject: |
[Qemu-devel] [PULL 7/9] sockets: allow SocketAddress 'fd' to reference numeric file descriptors |
Date: |
Mon, 12 Mar 2018 20:13:03 +0000 |
From: "Daniel P. Berrange" <address@hidden>
The SocketAddress 'fd' kind accepts the name of a file descriptor passed
to the monitor with the 'getfd' command. This makes it impossible to use
the 'fd' kind in cases where a monitor is not available. This can apply in
handling command line argv at startup, or simply if internal code wants to
use SocketAddress and pass a numeric FD it has acquired from elsewhere.
Fortunately the 'getfd' command mandated that the FD names must not start
with a leading digit. We can thus safely extend semantics of the
SocketAddress 'fd' kind, to allow a purely numeric name to reference an
file descriptor that QEMU already has open. There will be restrictions on
when each kind can be used.
In codepaths where we are handling a monitor command (ie cur_mon != NULL),
we will only support use of named file descriptors as before. Use of FD
numbers is still not permitted for monitor commands.
In codepaths where we are not handling a monitor command (ie cur_mon ==
NULL), we will not support named file descriptors. Instead we can reference
FD numers explicitly. This allows the app spawning QEMU to intentionally
"leak" a pre-opened socket to QEMU and reference that in a SocketAddress
definition, or for code inside QEMU to pass pre-opened FDs around.
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Marc-André Lureau <address@hidden>
Signed-off-by: Daniel P. Berrange <address@hidden>
---
qapi/sockets.json | 7 +++
tests/test-util-sockets.c | 112 +++++++++++++++++++++++++++++++++++++++++++---
util/qemu-sockets.c | 16 +++++--
3 files changed, 126 insertions(+), 9 deletions(-)
diff --git a/qapi/sockets.json b/qapi/sockets.json
index ac022c6ad0..fc81d8d5e8 100644
--- a/qapi/sockets.json
+++ b/qapi/sockets.json
@@ -123,6 +123,13 @@
#
# @unix: Unix domain socket
#
+# @vsock: VMCI address
+#
+# @fd: decimal is for file descriptor number, otherwise a file descriptor name.
+# Named file descriptors are permitted in monitor commands, in combination
+# with the 'getfd' command. Decimal file descriptors are permitted at
+# startup or other contexts where no monitor context is active.
+#
# Since: 2.9
##
{ 'enum': 'SocketAddressType',
diff --git a/tests/test-util-sockets.c b/tests/test-util-sockets.c
index 06eb0e4a28..acadd85e8f 100644
--- a/tests/test-util-sockets.c
+++ b/tests/test-util-sockets.c
@@ -73,7 +73,7 @@ Monitor *cur_mon;
void monitor_init(Chardev *chr, int flags) {}
-static void test_socket_fd_pass_good(void)
+static void test_socket_fd_pass_name_good(void)
{
SocketAddress addr;
int fd;
@@ -104,7 +104,7 @@ static void test_socket_fd_pass_good(void)
cur_mon = NULL;
}
-static void test_socket_fd_pass_bad(void)
+static void test_socket_fd_pass_name_bad(void)
{
SocketAddress addr;
Error *err = NULL;
@@ -134,6 +134,98 @@ static void test_socket_fd_pass_bad(void)
cur_mon = NULL;
}
+static void test_socket_fd_pass_name_nomon(void)
+{
+ SocketAddress addr;
+ Error *err = NULL;
+ int fd;
+
+ g_assert(cur_mon == NULL);
+
+ addr.type = SOCKET_ADDRESS_TYPE_FD;
+ addr.u.fd.str = g_strdup("myfd");
+
+ fd = socket_connect(&addr, &err);
+ g_assert_cmpint(fd, ==, -1);
+ error_free_or_abort(&err);
+
+ fd = socket_listen(&addr, &err);
+ g_assert_cmpint(fd, ==, -1);
+ error_free_or_abort(&err);
+
+ g_free(addr.u.fd.str);
+}
+
+
+static void test_socket_fd_pass_num_good(void)
+{
+ SocketAddress addr;
+ int fd, sfd;
+
+ g_assert(cur_mon == NULL);
+ sfd = qemu_socket(AF_INET, SOCK_STREAM, 0);
+ g_assert_cmpint(sfd, >, STDERR_FILENO);
+
+ addr.type = SOCKET_ADDRESS_TYPE_FD;
+ addr.u.fd.str = g_strdup_printf("%d", sfd);
+
+ fd = socket_connect(&addr, &error_abort);
+ g_assert_cmpint(fd, ==, sfd);
+
+ fd = socket_listen(&addr, &error_abort);
+ g_assert_cmpint(fd, ==, sfd);
+
+ g_free(addr.u.fd.str);
+ close(sfd);
+}
+
+static void test_socket_fd_pass_num_bad(void)
+{
+ SocketAddress addr;
+ Error *err = NULL;
+ int fd, sfd;
+
+ g_assert(cur_mon == NULL);
+ sfd = dup(STDOUT_FILENO);
+
+ addr.type = SOCKET_ADDRESS_TYPE_FD;
+ addr.u.fd.str = g_strdup_printf("%d", sfd);
+
+ fd = socket_connect(&addr, &err);
+ g_assert_cmpint(fd, ==, -1);
+ error_free_or_abort(&err);
+
+ fd = socket_listen(&addr, &err);
+ g_assert_cmpint(fd, ==, -1);
+ error_free_or_abort(&err);
+
+ g_free(addr.u.fd.str);
+ close(sfd);
+}
+
+static void test_socket_fd_pass_num_nocli(void)
+{
+ SocketAddress addr;
+ Error *err = NULL;
+ int fd;
+
+ cur_mon = g_malloc(1); /* Fake a monitor */
+
+ addr.type = SOCKET_ADDRESS_TYPE_FD;
+ addr.u.fd.str = g_strdup_printf("%d", STDOUT_FILENO);
+
+ fd = socket_connect(&addr, &err);
+ g_assert_cmpint(fd, ==, -1);
+ error_free_or_abort(&err);
+
+ fd = socket_listen(&addr, &err);
+ g_assert_cmpint(fd, ==, -1);
+ error_free_or_abort(&err);
+
+ g_free(addr.u.fd.str);
+}
+
+
int main(int argc, char **argv)
{
bool has_ipv4, has_ipv6;
@@ -156,10 +248,18 @@ int main(int argc, char **argv)
test_fd_is_socket_bad);
g_test_add_func("/util/socket/is-socket/good",
test_fd_is_socket_good);
- g_test_add_func("/socket/fd-pass/good",
- test_socket_fd_pass_good);
- g_test_add_func("/socket/fd-pass/bad",
- test_socket_fd_pass_bad);
+ g_test_add_func("/socket/fd-pass/name/good",
+ test_socket_fd_pass_name_good);
+ g_test_add_func("/socket/fd-pass/name/bad",
+ test_socket_fd_pass_name_bad);
+ g_test_add_func("/socket/fd-pass/name/nomon",
+ test_socket_fd_pass_name_nomon);
+ g_test_add_func("/socket/fd-pass/num/good",
+ test_socket_fd_pass_num_good);
+ g_test_add_func("/socket/fd-pass/num/bad",
+ test_socket_fd_pass_num_bad);
+ g_test_add_func("/socket/fd-pass/num/nocli",
+ test_socket_fd_pass_num_nocli);
}
return g_test_run();
diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 6dc4613855..8bd8bb64eb 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -1044,9 +1044,19 @@ fail:
static int socket_get_fd(const char *fdstr, Error **errp)
{
- int fd = monitor_get_fd(cur_mon, fdstr, errp);
- if (fd < 0) {
- return -1;
+ int fd;
+ if (cur_mon) {
+ fd = monitor_get_fd(cur_mon, fdstr, errp);
+ if (fd < 0) {
+ return -1;
+ }
+ } else {
+ if (qemu_strtoi(fdstr, NULL, 10, &fd) < 0) {
+ error_setg_errno(errp, errno,
+ "Unable to parse FD number %s",
+ fdstr);
+ return -1;
+ }
}
if (!fd_is_socket(fd)) {
error_setg(errp, "File descriptor '%s' is not a socket", fdstr);
--
2.14.3
- [Qemu-devel] [PULL 0/9] Socket next patches, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 6/9] sockets: check that the named file descriptor is a socket, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 5/9] sockets: move fd_is_socket() into common sockets code, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 1/9] char: don't silently skip tn3270 protocol init when TLS is enabled, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 4/9] sockets: strengthen test suite IP protocol availability checks, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 7/9] sockets: allow SocketAddress 'fd' to reference numeric file descriptors,
Daniel P . Berrangé <=
- [Qemu-devel] [PULL 3/9] sockets: pull code for testing IP availability out of specific test, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 2/9] cutils: add qemu_strtoi & qemu_strtoui parsers for int/unsigned int types, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 8/9] char: refactor parsing of socket address information, Daniel P . Berrangé, 2018/03/12
- [Qemu-devel] [PULL 9/9] char: allow passing pre-opened socket file descriptor at startup, Daniel P . Berrangé, 2018/03/12
- Re: [Qemu-devel] [PULL 0/9] Socket next patches, no-reply, 2018/03/12
- Re: [Qemu-devel] [PULL 0/9] Socket next patches, Peter Maydell, 2018/03/13