From 776b97d3605ed0fc94443048fdf988c7725e38a9 Mon Sep 17 00:00:00 2001 From: xiaoqiang zhao Date: Sat, 16 May 2020 11:13:25 +0800 Subject: [PATCH] qemu-sockets: add abstract UNIX domain socket support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit unix_listen/connect_saddr now support abstract address types two aditional BOOL switches are introduced: tight: whether to set @addrlen to the minimal string length, or the maximum sun_path length. default is TRUE abstract: whether we use abstract address. default is FALSE cli example: -monitor unix:/tmp/unix.socket,abstract,tight=off OR -chardev socket,path=/tmp/unix.socket,id=unix1,abstract,tight=on Signed-off-by: xiaoqiang zhao Signed-off-by: Daniel P. Berrangé --- chardev/char-socket.c | 4 ++++ chardev/char.c | 7 +++++++ qapi/sockets.json | 8 +++++++- util/qemu-sockets.c | 39 ++++++++++++++++++++++++++++++++------- 4 files changed, 50 insertions(+), 8 deletions(-) diff --git a/chardev/char-socket.c b/chardev/char-socket.c index 232e0a8604..e77699db48 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -1380,6 +1380,8 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend, const char *host = qemu_opt_get(opts, "host"); const char *port = qemu_opt_get(opts, "port"); const char *fd = qemu_opt_get(opts, "fd"); + bool tight = qemu_opt_get_bool(opts, "tight", true); + bool abstract = qemu_opt_get_bool(opts, "abstract", false); SocketAddressLegacy *addr; ChardevSocket *sock; @@ -1431,6 +1433,8 @@ static void qemu_chr_parse_socket(QemuOpts *opts, ChardevBackend *backend, addr->type = SOCKET_ADDRESS_LEGACY_KIND_UNIX; q_unix = addr->u.q_unix.data = g_new0(UnixSocketAddress, 1); q_unix->path = g_strdup(path); + q_unix->tight = tight; + q_unix->abstract = abstract; } else if (host) { addr->type = SOCKET_ADDRESS_LEGACY_KIND_INET; addr->u.inet.data = g_new(InetSocketAddress, 1); diff --git a/chardev/char.c b/chardev/char.c index 0196e2887b..ea06c5ff4d 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -939,6 +939,13 @@ QemuOptsList qemu_chardev_opts = { },{ .name = "logappend", .type = QEMU_OPT_BOOL, + },{ + .name = "tight", + .type = QEMU_OPT_BOOL, + .def_value_str = "on", + },{ + .name = "abstract", + .type = QEMU_OPT_BOOL, }, { /* end of list */ } }, diff --git a/qapi/sockets.json b/qapi/sockets.json index ea933ed4b2..cbd6ef35d0 100644 --- a/qapi/sockets.json +++ b/qapi/sockets.json @@ -73,12 +73,18 @@ # Captures a socket address in the local ("Unix socket") namespace. # # @path: filesystem path to use +# @tight: pass a socket address length confined to the minimum length of the +# abstract string, rather than the full sockaddr_un record length +# (only matters for abstract sockets, default true). (Since 5.1) +# @abstract: whether this is an abstract address, default false. (Since 5.1) # # Since: 1.3 ## { 'struct': 'UnixSocketAddress', 'data': { - 'path': 'str' } } + 'path': 'str', + '*tight': 'bool', + '*abstract': 'bool' } } ## # @VsockSocketAddress: diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index 86c48b9fa5..b37d288866 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -863,6 +863,7 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, char *pathbuf = NULL; const char *path; size_t pathlen; + size_t addrlen; sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0); if (sock < 0) { @@ -879,9 +880,11 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, } pathlen = strlen(path); - if (pathlen > sizeof(un.sun_path)) { + if (pathlen > sizeof(un.sun_path) || + (saddr->abstract && pathlen > (sizeof(un.sun_path) - 1))) { error_setg(errp, "UNIX socket path '%s' is too long", path); error_append_hint(errp, "Path must be less than %zu bytes\n", + saddr->abstract ? sizeof(un.sun_path) - 1 : sizeof(un.sun_path)); goto err; } @@ -903,7 +906,7 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, close(fd); } - if (unlink(path) < 0 && errno != ENOENT) { + if (!saddr->abstract && unlink(path) < 0 && errno != ENOENT) { error_setg_errno(errp, errno, "Failed to unlink socket %s", path); goto err; @@ -911,9 +914,19 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, memset(&un, 0, sizeof(un)); un.sun_family = AF_UNIX; - memcpy(un.sun_path, path, pathlen); + addrlen = sizeof(un); - if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) { + if (saddr->abstract) { + un.sun_path[0] = '\0'; + memcpy(&un.sun_path[1], path, pathlen); + if (saddr->tight) { + addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + pathlen; + } + } else { + memcpy(un.sun_path, path, pathlen); + } + + if (bind(sock, (struct sockaddr *) &un, addrlen) < 0) { error_setg_errno(errp, errno, "Failed to bind socket to %s", path); goto err; } @@ -936,6 +949,7 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) struct sockaddr_un un; int sock, rc; size_t pathlen; + size_t addrlen; if (saddr->path == NULL) { error_setg(errp, "unix connect: no path specified"); @@ -949,21 +963,32 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) } pathlen = strlen(saddr->path); - if (pathlen > sizeof(un.sun_path)) { + if (pathlen > sizeof(un.sun_path) || + (saddr->abstract && pathlen > (sizeof(un.sun_path) - 1))) { error_setg(errp, "UNIX socket path '%s' is too long", saddr->path); error_append_hint(errp, "Path must be less than %zu bytes\n", + saddr->abstract ? sizeof(un.sun_path) - 1 : sizeof(un.sun_path)); goto err; } memset(&un, 0, sizeof(un)); un.sun_family = AF_UNIX; - memcpy(un.sun_path, saddr->path, pathlen); + addrlen = sizeof(un); + if (saddr->abstract) { + un.sun_path[0] = '\0'; + memcpy(&un.sun_path[1], saddr->path, pathlen); + if (saddr->tight) { + addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + pathlen; + } + } else { + memcpy(un.sun_path, saddr->path, pathlen); + } /* connect to peer */ do { rc = 0; - if (connect(sock, (struct sockaddr *) &un, sizeof(un)) < 0) { + if (connect(sock, (struct sockaddr *) &un, addrlen) < 0) { rc = -errno; } } while (rc == -EINTR);