The abstract socket namespace is a non-portable Linux extension. An attempt to use it elsewhere should fail with ENOENT (the abstract address looks like a "" pathname, which does not resolve). We report this failure like
Failed to connect socket abc: No such file or directory Tolerable, although ENOTSUP would be better. However, introspection lies: it has @abstract regardless of host support. Easy enough to fix: since Linux provides them since 2.2, 'if': 'defined(CONFIG_LINUX)' should do. The above failure becomes Parameter 'backend.data.addr.data.abstract' is unexpected I consider this an improvement. Signed-off-by: Markus Armbruster <arm...@redhat.com> --- qapi/sockets.json | 14 ++++++++------ chardev/char-socket.c | 10 ++++++++++ chardev/char.c | 2 ++ tests/test-util-sockets.c | 7 ++++--- util/qemu-sockets.c | 40 +++++++++++++++++++++++++++++---------- 5 files changed, 54 insertions(+), 19 deletions(-) diff --git a/qapi/sockets.json b/qapi/sockets.json index c0c640a5b0..db4019306a 100644 --- a/qapi/sockets.json +++ b/qapi/sockets.json @@ -74,18 +74,20 @@ # 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) +# @abstract: if true, this is a Linux abstract socket address. @path +# will be prefixed by a null byte, and optionally padded +# with null bytes. Defaults to false. (Since 5.1) +# @tight: if false, pad an abstract socket address with enough null +# bytes to make it fill struct sockaddr_un member sun_path. +# Defaults to true. (Since 5.1) # # Since: 1.3 ## { 'struct': 'UnixSocketAddress', 'data': { 'path': 'str', - '*tight': 'bool', - '*abstract': 'bool' } } + '*tight': { 'type': 'bool', 'if': 'defined(CONFIG_LINUX)' }, + '*abstract': { 'type': 'bool', 'if': 'defined(CONFIG_LINUX)' } } } ## # @VsockSocketAddress: diff --git a/chardev/char-socket.c b/chardev/char-socket.c index dc1cf86ecf..1d2b2efb13 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -444,14 +444,20 @@ static char *qemu_chr_socket_address(SocketChardev *s, const char *prefix) break; case SOCKET_ADDRESS_TYPE_UNIX: { +#ifdef CONFIG_LINUX UnixSocketAddress *sa = &s->addr->u.q_unix; +#endif return g_strdup_printf("%sunix:%s%s%s%s", prefix, s->addr->u.q_unix.path, +#ifdef CONFIG_LINUX sa->has_abstract && sa->abstract ? ",abstract" : "", sa->has_tight && sa->tight ? ",tight" : "", +#else + "", "", +#endif s->is_listen ? ",server" : ""); break; } @@ -1394,8 +1400,10 @@ 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"); +#ifdef CONFIG_LINUX bool tight = qemu_opt_get_bool(opts, "tight", true); bool abstract = qemu_opt_get_bool(opts, "abstract", false); +#endif SocketAddressLegacy *addr; ChardevSocket *sock; @@ -1447,10 +1455,12 @@ 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); +#ifdef CONFIG_LINUX q_unix->has_tight = true; q_unix->tight = tight; q_unix->has_abstract = true; q_unix->abstract = abstract; +#endif } 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 78553125d3..aa4282164a 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -928,6 +928,7 @@ QemuOptsList qemu_chardev_opts = { },{ .name = "logappend", .type = QEMU_OPT_BOOL, +#ifdef CONFIG_LINUX },{ .name = "tight", .type = QEMU_OPT_BOOL, @@ -935,6 +936,7 @@ QemuOptsList qemu_chardev_opts = { },{ .name = "abstract", .type = QEMU_OPT_BOOL, +#endif }, { /* end of list */ } }, diff --git a/tests/test-util-sockets.c b/tests/test-util-sockets.c index 7ecf95579b..67486055ed 100644 --- a/tests/test-util-sockets.c +++ b/tests/test-util-sockets.c @@ -229,7 +229,7 @@ static void test_socket_fd_pass_num_nocli(void) } #endif -#ifdef __linux__ +#ifdef CONFIG_LINUX #define ABSTRACT_SOCKET_VARIANTS 3 @@ -326,7 +326,8 @@ static void test_socket_unix_abstract(void) g_free(addr.u.q_unix.path); } -#endif + +#endif /* CONFIG_LINUX */ int main(int argc, char **argv) { @@ -368,7 +369,7 @@ int main(int argc, char **argv) #endif } -#ifdef __linux__ +#ifdef CONFIG_LINUX g_test_add_func("/util/socket/unix-abstract", test_socket_unix_abstract); #endif diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index 18c8de8cdb..f8553976e6 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -854,10 +854,29 @@ static int vsock_parse(VsockSocketAddress *addr, const char *str, #ifndef _WIN32 +static bool saddr_is_abstract(UnixSocketAddress *saddr) +{ +#ifdef CONFIG_LINUX + return saddr->abstract; +#else + return false; +#endif +} + +static bool saddr_is_tight(UnixSocketAddress *saddr) +{ +#ifdef CONFIG_LINUX + return !saddr->has_tight || saddr->tight; +#else + return false; +#endif +} + static int unix_listen_saddr(UnixSocketAddress *saddr, int num, Error **errp) { + bool abstract = saddr_is_abstract(saddr); struct sockaddr_un un; int sock, fd; char *pathbuf = NULL; @@ -871,7 +890,7 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, return -1; } - if (saddr->path[0] || saddr->abstract) { + if (saddr->path[0] || abstract) { path = saddr->path; } else { const char *tmpdir = getenv("TMPDIR"); @@ -881,10 +900,10 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, pathlen = strlen(path); if (pathlen > sizeof(un.sun_path) || - (saddr->abstract && pathlen > (sizeof(un.sun_path) - 1))) { + (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 : + abstract ? sizeof(un.sun_path) - 1 : sizeof(un.sun_path)); goto err; } @@ -906,7 +925,7 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, close(fd); } - if (!saddr->abstract && unlink(path) < 0 && errno != ENOENT) { + if (!abstract && unlink(path) < 0 && errno != ENOENT) { error_setg_errno(errp, errno, "Failed to unlink socket %s", path); goto err; @@ -916,10 +935,10 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, un.sun_family = AF_UNIX; addrlen = sizeof(un); - if (saddr->abstract) { + if (abstract) { un.sun_path[0] = '\0'; memcpy(&un.sun_path[1], path, pathlen); - if (!saddr->has_tight || saddr->tight) { + if (!saddr_is_tight(saddr)) { addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + pathlen; } } else { @@ -946,6 +965,7 @@ err: static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) { + bool abstract = saddr_is_abstract(saddr); struct sockaddr_un un; int sock, rc; size_t pathlen; @@ -964,10 +984,10 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) pathlen = strlen(saddr->path); if (pathlen > sizeof(un.sun_path) || - (saddr->abstract && pathlen > (sizeof(un.sun_path) - 1))) { + (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 : + abstract ? sizeof(un.sun_path) - 1 : sizeof(un.sun_path)); goto err; } @@ -976,10 +996,10 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) un.sun_family = AF_UNIX; addrlen = sizeof(un); - if (saddr->abstract) { + if (abstract) { un.sun_path[0] = '\0'; memcpy(&un.sun_path[1], saddr->path, pathlen); - if (!saddr->has_tight || saddr->tight) { + if (!saddr_is_tight(saddr)) { addrlen = offsetof(struct sockaddr_un, sun_path) + 1 + pathlen; } } else { -- 2.26.2