1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <fcntl.h>
#include <poll.h>
#include <pthread.h>
#include "sd-event.h"
#include "fd-util.h"
#include "json.h"
#include "rm-rf.h"
#include "strv.h"
#include "tmpfile-util.h"
#include "user-util.h"
#include "varlink.h"
/* Let's pick some high value, that is higher than the largest listen() backlog, but leaves enough room below
the typical RLIMIT_NOFILE value of 1024 so that we can process both sides of each socket in our
process. Or in other words: "OVERLOAD_CONNECTIONS * 2 + x < 1024" should hold, for some small x that
should cover any auxiliary fds, the listener server fds, stdin/stdout/stderr and whatever else. */
#define OVERLOAD_CONNECTIONS 333
static int n_done = 0;
static int block_write_fd = -1;
static int method_something(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
_cleanup_(json_variant_unrefp) JsonVariant *ret = NULL;
JsonVariant *a, *b;
int64_t x, y;
int r;
a = json_variant_by_key(parameters, "a");
if (!a)
return varlink_error(link, "io.test.BadParameters", NULL);
x = json_variant_integer(a);
b = json_variant_by_key(parameters, "b");
if (!b)
return varlink_error(link, "io.test.BadParameters", NULL);
y = json_variant_integer(b);
r = json_build(&ret, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("sum", JSON_BUILD_INTEGER(x + y))));
if (r < 0)
return r;
return varlink_reply(link, ret);
}
static int method_done(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
if (++n_done == 2)
sd_event_exit(varlink_get_event(link), EXIT_FAILURE);
return 0;
}
static int reply(Varlink *link, JsonVariant *parameters, const char *error_id, VarlinkReplyFlags flags, void *userdata) {
JsonVariant *sum;
sum = json_variant_by_key(parameters, "sum");
assert_se(json_variant_integer(sum) == 7+22);
if (++n_done == 2)
sd_event_exit(varlink_get_event(link), EXIT_FAILURE);
return 0;
}
static int on_connect(VarlinkServer *s, Varlink *link, void *userdata) {
uid_t uid = UID_INVALID;
assert_se(s);
assert_se(link);
assert_se(varlink_get_peer_uid(link, &uid) >= 0);
assert_se(getuid() == uid);
return 0;
}
static int overload_reply(Varlink *link, JsonVariant *parameters, const char *error_id, VarlinkReplyFlags flags, void *userdata) {
/* This method call reply should always be called with a disconnection, since the method call should
* be talking to an overloaded server */
log_debug("Over reply triggered with error: %s", strna(error_id));
assert_se(streq(error_id, VARLINK_ERROR_DISCONNECTED));
sd_event_exit(varlink_get_event(link), 0);
return 0;
}
static void flood_test(const char *address) {
_cleanup_(varlink_flush_close_unrefp) Varlink *c = NULL;
_cleanup_(sd_event_unrefp) sd_event *e = NULL;
_cleanup_free_ Varlink **connections = NULL;
size_t k;
char x = 'x';
log_debug("Flooding server...");
/* Block the main event loop while we flood */
assert_se(write(block_write_fd, &x, sizeof(x)) == sizeof(x));
assert_se(sd_event_default(&e) >= 0);
/* Flood the server with connections */
assert_se(connections = new0(Varlink*, OVERLOAD_CONNECTIONS));
for (k = 0; k < OVERLOAD_CONNECTIONS; k++) {
_cleanup_free_ char *t = NULL;
log_debug("connection %zu", k);
assert_se(varlink_connect_address(connections + k, address) >= 0);
assert_se(asprintf(&t, "flood-%zu", k) >= 0);
assert_se(varlink_set_description(connections[k], t) >= 0);
assert_se(varlink_attach_event(connections[k], e, k) >= 0);
assert_se(varlink_sendb(connections[k], "io.test.Rubbish", JSON_BUILD_OBJECT(JSON_BUILD_PAIR("id", JSON_BUILD_INTEGER(k)))) >= 0);
}
/* Then, create one more, which should fail */
log_debug("Creating overload connection...");
assert_se(varlink_connect_address(&c, address) >= 0);
assert_se(varlink_set_description(c, "overload-client") >= 0);
assert_se(varlink_attach_event(c, e, k) >= 0);
assert_se(varlink_bind_reply(c, overload_reply) >= 0);
assert_se(varlink_invokeb(c, "io.test.Overload", JSON_BUILD_OBJECT(JSON_BUILD_PAIR("foo", JSON_BUILD_CONST_STRING("bar")))) >= 0);
/* Unblock it */
log_debug("Unblocking server...");
block_write_fd = safe_close(block_write_fd);
/* This loop will terminate as soon as the overload reply callback is called */
assert_se(sd_event_loop(e) >= 0);
/* And close all connections again */
for (k = 0; k < OVERLOAD_CONNECTIONS; k++)
connections[k] = varlink_unref(connections[k]);
}
static void *thread(void *arg) {
_cleanup_(varlink_flush_close_unrefp) Varlink *c = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *i = NULL;
JsonVariant *o = NULL;
const char *e;
assert_se(json_build(&i, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("a", JSON_BUILD_INTEGER(88)),
JSON_BUILD_PAIR("b", JSON_BUILD_INTEGER(99)))) >= 0);
assert_se(varlink_connect_address(&c, arg) >= 0);
assert_se(varlink_set_description(c, "thread-client") >= 0);
assert_se(varlink_call(c, "io.test.DoSomething", i, &o, &e, NULL) >= 0);
assert_se(json_variant_integer(json_variant_by_key(o, "sum")) == 88 + 99);
assert_se(!e);
assert_se(varlink_callb(c, "io.test.IDontExist", &o, &e, NULL, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("x", JSON_BUILD_REAL(5.5)))) >= 0);
assert_se(streq_ptr(json_variant_string(json_variant_by_key(o, "method")), "io.test.IDontExist"));
assert_se(streq(e, VARLINK_ERROR_METHOD_NOT_FOUND));
flood_test(arg);
assert_se(varlink_send(c, "io.test.Done", NULL) >= 0);
return NULL;
}
static int block_fd_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
char c;
assert_se(fd_nonblock(fd, false) >= 0);
assert_se(read(fd, &c, sizeof(c)) == sizeof(c));
/* When a character is written to this pipe we'll block until the pipe is closed. */
assert_se(read(fd, &c, sizeof(c)) == 0);
assert_se(fd_nonblock(fd, true) >= 0);
assert_se(sd_event_source_set_enabled(s, SD_EVENT_OFF) >= 0);
return 0;
}
int main(int argc, char *argv[]) {
_cleanup_(sd_event_source_unrefp) sd_event_source *block_event = NULL;
_cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL;
_cleanup_(varlink_flush_close_unrefp) Varlink *c = NULL;
_cleanup_(rm_rf_physical_and_freep) char *tmpdir = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
_cleanup_(sd_event_unrefp) sd_event *e = NULL;
_cleanup_(close_pairp) int block_fds[2] = { -1, -1 };
pthread_t t;
const char *sp;
log_set_max_level(LOG_DEBUG);
log_open();
assert_se(mkdtemp_malloc("/tmp/varlink-test-XXXXXX", &tmpdir) >= 0);
sp = strjoina(tmpdir, "/socket");
assert_se(sd_event_default(&e) >= 0);
assert_se(pipe2(block_fds, O_NONBLOCK|O_CLOEXEC) >= 0);
assert_se(sd_event_add_io(e, &block_event, block_fds[0], EPOLLIN, block_fd_handler, NULL) >= 0);
assert_se(sd_event_source_set_priority(block_event, SD_EVENT_PRIORITY_IMPORTANT) >= 0);
block_write_fd = TAKE_FD(block_fds[1]);
assert_se(varlink_server_new(&s, VARLINK_SERVER_ACCOUNT_UID) >= 0);
assert_se(varlink_server_set_description(s, "our-server") >= 0);
assert_se(varlink_server_bind_method(s, "io.test.DoSomething", method_something) >= 0);
assert_se(varlink_server_bind_method(s, "io.test.Done", method_done) >= 0);
assert_se(varlink_server_bind_connect(s, on_connect) >= 0);
assert_se(varlink_server_listen_address(s, sp, 0600) >= 0);
assert_se(varlink_server_attach_event(s, e, 0) >= 0);
assert_se(varlink_server_set_connections_max(s, OVERLOAD_CONNECTIONS) >= 0);
assert_se(varlink_connect_address(&c, sp) >= 0);
assert_se(varlink_set_description(c, "main-client") >= 0);
assert_se(varlink_bind_reply(c, reply) >= 0);
assert_se(json_build(&v, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("a", JSON_BUILD_INTEGER(7)),
JSON_BUILD_PAIR("b", JSON_BUILD_INTEGER(22)))) >= 0);
assert_se(varlink_invoke(c, "io.test.DoSomething", v) >= 0);
assert_se(varlink_attach_event(c, e, 0) >= 0);
assert_se(pthread_create(&t, NULL, thread, (void*) sp) == 0);
assert_se(sd_event_loop(e) >= 0);
assert_se(pthread_join(t, NULL) == 0);
return 0;
}
|
