qemu/tests/test-util-sockets.c
Peter Xu 62aa1d887f monitor: Fix unsafe sharing of @cur_mon among threads
@cur_mon is null unless the main thread is running monitor code, either
HMP code within monitor_read(), or QMP code within
monitor_qmp_dispatch().

Use of @cur_mon outside the main thread is therefore unsafe.

Most of its uses are in monitor command handlers.  These run in the main
thread.

However, there are also uses hiding elsewhere, such as in
error_vprintf(), and thus error_report(), making these functions unsafe
outside the main thread.  No such unsafe uses are known at this time.
Regardless, this is an unnecessary trap.  It's an ancient trap, though.

More recently, commit cf869d5317 "qmp: support out-of-band (oob)
execution" spiced things up: the monitor I/O thread assigns to @cur_mon
when executing commands out-of-band.  Having two threads save, set and
restore @cur_mon without synchronization is definitely unsafe.  We can
end up with @cur_mon null while the main thread runs monitor code, or
non-null while it runs non-monitor code.

We could fix this by making the I/O thread not mess with @cur_mon, but
that would leave the trap armed and ready.

Instead, make @cur_mon thread-local.  It's now reliably null unless the
thread is running monitor code.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[peterx: update subject and commit message written by Markus]
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180720033451.32710-1-peterx@redhat.com>
2018-07-23 14:00:03 +02:00

267 lines
6.6 KiB
C

/*
* Tests for util/qemu-sockets.c
*
* Copyright 2018 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/sockets.h"
#include "qapi/error.h"
#include "socket-helpers.h"
#include "monitor/monitor.h"
static void test_fd_is_socket_bad(void)
{
char *tmp = g_strdup("qemu-test-util-sockets-XXXXXX");
int fd = mkstemp(tmp);
if (fd != 0) {
unlink(tmp);
}
g_free(tmp);
g_assert(fd >= 0);
g_assert(!fd_is_socket(fd));
close(fd);
}
static void test_fd_is_socket_good(void)
{
int fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
g_assert(fd >= 0);
g_assert(fd_is_socket(fd));
close(fd);
}
static int mon_fd = -1;
static const char *mon_fdname;
int monitor_get_fd(Monitor *mon, const char *fdname, Error **errp)
{
g_assert(cur_mon);
g_assert(mon == cur_mon);
if (mon_fd == -1 || !g_str_equal(mon_fdname, fdname)) {
error_setg(errp, "No fd named %s", fdname);
return -1;
}
return dup(mon_fd);
}
/* Syms in libqemustub.a are discarded at .o file granularity.
* To replace monitor_get_fd() we must ensure everything in
* stubs/monitor.c is defined, to make sure monitor.o is discarded
* otherwise we get duplicate syms at link time.
*/
__thread Monitor *cur_mon;
void monitor_init(Chardev *chr, int flags) {}
static void test_socket_fd_pass_name_good(void)
{
SocketAddress addr;
int fd;
cur_mon = g_malloc(1); /* Fake a monitor */
mon_fdname = "myfd";
mon_fd = qemu_socket(AF_INET, SOCK_STREAM, 0);
g_assert_cmpint(mon_fd, >, STDERR_FILENO);
addr.type = SOCKET_ADDRESS_TYPE_FD;
addr.u.fd.str = g_strdup(mon_fdname);
fd = socket_connect(&addr, &error_abort);
g_assert_cmpint(fd, !=, -1);
g_assert_cmpint(fd, !=, mon_fd);
close(fd);
fd = socket_listen(&addr, &error_abort);
g_assert_cmpint(fd, !=, -1);
g_assert_cmpint(fd, !=, mon_fd);
close(fd);
g_free(addr.u.fd.str);
mon_fdname = NULL;
close(mon_fd);
mon_fd = -1;
g_free(cur_mon);
cur_mon = NULL;
}
static void test_socket_fd_pass_name_bad(void)
{
SocketAddress addr;
Error *err = NULL;
int fd;
cur_mon = g_malloc(1); /* Fake a monitor */
mon_fdname = "myfd";
mon_fd = dup(STDOUT_FILENO);
g_assert_cmpint(mon_fd, >, STDERR_FILENO);
addr.type = SOCKET_ADDRESS_TYPE_FD;
addr.u.fd.str = g_strdup(mon_fdname);
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);
mon_fdname = NULL;
close(mon_fd);
mon_fd = -1;
g_free(cur_mon);
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;
socket_init();
g_test_init(&argc, &argv, NULL);
/* We're creating actual IPv4/6 sockets, so we should
* check if the host running tests actually supports
* each protocol to avoid breaking tests on machines
* with either IPv4 or IPv6 disabled.
*/
if (socket_check_protocol_support(&has_ipv4, &has_ipv6) < 0) {
return 1;
}
if (has_ipv4) {
g_test_add_func("/util/socket/is-socket/bad",
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/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();
}