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sockets: Make abstract UnixSocketAddress depend on CONFIG_LINUX 

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.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Markus Armbruster 2020-11-02 10:44:22 +01:00 committed by Daniel P. Berrangé
parent ef298e3826
commit 8acefc79de
5 changed files with 50 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
chardev/char-socket.c
View File

@ -447,12 +447,14 @@ static char *qemu_chr_socket_address(SocketChardev *s, const char *prefix)
const char *tight = "", *abstract = "";
UnixSocketAddress *sa = &s->addr->u.q_unix;
#ifdef CONFIG_LINUX
if (sa->has_abstract && sa->abstract) {
abstract = ",abstract";
if (sa->has_tight && sa->tight) {
tight = ",tight";
}
}
#endif
return g_strdup_printf("%sunix:%s%s%s%s", prefix, sa->path,
abstract, tight,
@ -1398,8 +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;
@ -1451,10 +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);

2
chardev/char.c
View File

@ -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 */ }
},

14
qapi/sockets.json
View File

@ -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' } }
'*abstract': { 'type': 'bool', 'if': 'defined(CONFIG_LINUX)' },
'*tight': { 'type': 'bool', 'if': 'defined(CONFIG_LINUX)' } } }
##
# @VsockSocketAddress:

7
tests/test-util-sockets.c
View File

@ -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

40
util/qemu-sockets.c
View File

@ -860,10 +860,29 @@ 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;
@ -877,7 +896,7 @@ 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");
@ -887,10 +906,10 @@ 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;
}
@ -912,7 +931,7 @@ 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;
@ -922,10 +941,10 @@ 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 {
@ -952,6 +971,7 @@ 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;
@ -970,10 +990,10 @@ 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;
}
@ -982,10 +1002,10 @@ 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 {