From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39737) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1evTp1-0004Fq-Nd for qemu-devel@nongnu.org; Mon, 12 Mar 2018 16:13:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1evTp0-00076u-0q for qemu-devel@nongnu.org; Mon, 12 Mar 2018 16:13:27 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51452 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1evToz-00076f-Qi for qemu-devel@nongnu.org; Mon, 12 Mar 2018 16:13:25 -0400 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Mon, 12 Mar 2018 20:13:03 +0000 Message-Id: <20180312201305.16972-8-berrange@redhat.com> In-Reply-To: <20180312201305.16972-1-berrange@redhat.com> References: <20180312201305.16972-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 7/9] sockets: allow SocketAddress 'fd' to reference numeric file descriptors List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Gerd Hoffmann , Markus Armbruster , Eric Blake , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini , Peter Maydell From: "Daniel P. Berrange" 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 i= n handling command line argv at startup, or simply if internal code wants t= o 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 !=3D NUL= L), 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 =3D=3D NULL), we will not support named file descriptors. Instead we can referen= ce 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 Reviewed-by: Marc-Andr=C3=A9 Lureau Signed-off-by: Daniel P. Berrange --- 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 descripto= r name. +# Named file descriptors are permitted in monitor commands, in comb= ination +# 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) {} =20 =20 -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 =3D NULL; } =20 -static void test_socket_fd_pass_bad(void) +static void test_socket_fd_pass_name_bad(void) { SocketAddress addr; Error *err =3D NULL; @@ -134,6 +134,98 @@ static void test_socket_fd_pass_bad(void) cur_mon =3D NULL; } =20 +static void test_socket_fd_pass_name_nomon(void) +{ + SocketAddress addr; + Error *err =3D NULL; + int fd; + + g_assert(cur_mon =3D=3D NULL); + + addr.type =3D SOCKET_ADDRESS_TYPE_FD; + addr.u.fd.str =3D g_strdup("myfd"); + + fd =3D socket_connect(&addr, &err); + g_assert_cmpint(fd, =3D=3D, -1); + error_free_or_abort(&err); + + fd =3D socket_listen(&addr, &err); + g_assert_cmpint(fd, =3D=3D, -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 =3D=3D NULL); + sfd =3D qemu_socket(AF_INET, SOCK_STREAM, 0); + g_assert_cmpint(sfd, >, STDERR_FILENO); + + addr.type =3D SOCKET_ADDRESS_TYPE_FD; + addr.u.fd.str =3D g_strdup_printf("%d", sfd); + + fd =3D socket_connect(&addr, &error_abort); + g_assert_cmpint(fd, =3D=3D, sfd); + + fd =3D socket_listen(&addr, &error_abort); + g_assert_cmpint(fd, =3D=3D, sfd); + + g_free(addr.u.fd.str); + close(sfd); +} + +static void test_socket_fd_pass_num_bad(void) +{ + SocketAddress addr; + Error *err =3D NULL; + int fd, sfd; + + g_assert(cur_mon =3D=3D NULL); + sfd =3D dup(STDOUT_FILENO); + + addr.type =3D SOCKET_ADDRESS_TYPE_FD; + addr.u.fd.str =3D g_strdup_printf("%d", sfd); + + fd =3D socket_connect(&addr, &err); + g_assert_cmpint(fd, =3D=3D, -1); + error_free_or_abort(&err); + + fd =3D socket_listen(&addr, &err); + g_assert_cmpint(fd, =3D=3D, -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 =3D NULL; + int fd; + + cur_mon =3D g_malloc(1); /* Fake a monitor */ + + addr.type =3D SOCKET_ADDRESS_TYPE_FD; + addr.u.fd.str =3D g_strdup_printf("%d", STDOUT_FILENO); + + fd =3D socket_connect(&addr, &err); + g_assert_cmpint(fd, =3D=3D, -1); + error_free_or_abort(&err); + + fd =3D socket_listen(&addr, &err); + g_assert_cmpint(fd, =3D=3D, -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); } =20 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: =20 static int socket_get_fd(const char *fdstr, Error **errp) { - int fd =3D monitor_get_fd(cur_mon, fdstr, errp); - if (fd < 0) { - return -1; + int fd; + if (cur_mon) { + fd =3D 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); --=20 2.14.3