aboutsummaryrefslogtreecommitdiffhomepage
path: root/test/core/iomgr/fd_posix_test.c
blob: 62dc24d85a7a3baccae2bb27aedab656c2967abb (plain)
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
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "src/core/lib/iomgr/ev_posix.h"

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <unistd.h>

#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include <grpc/support/time.h>

#include "src/core/lib/iomgr/ev_posix.h"
#include "src/core/lib/iomgr/iomgr.h"
#include "src/core/lib/iomgr/socket_utils_posix.h"
#include "test/core/util/test_config.h"

static gpr_mu *g_mu;
static grpc_pollset *g_pollset;

/* buffer size used to send and receive data.
   1024 is the minimal value to set TCP send and receive buffer. */
#define BUF_SIZE 1024

/* Create a test socket with the right properties for testing.
   port is the TCP port to listen or connect to.
   Return a socket FD and sockaddr_in. */
static void create_test_socket(int port, int *socket_fd,
                               struct sockaddr_in *sin) {
  int fd;
  int one = 1;
  int buffer_size_bytes = BUF_SIZE;
  int flags;

  fd = socket(AF_INET, SOCK_STREAM, 0);
  setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
  /* Reset the size of socket send buffer to the minimal value to facilitate
     buffer filling up and triggering notify_on_write  */
  GPR_ASSERT(grpc_set_socket_sndbuf(fd, buffer_size_bytes) == GRPC_ERROR_NONE);
  GPR_ASSERT(grpc_set_socket_rcvbuf(fd, buffer_size_bytes) == GRPC_ERROR_NONE);
  /* Make fd non-blocking */
  flags = fcntl(fd, F_GETFL, 0);
  GPR_ASSERT(fcntl(fd, F_SETFL, flags | O_NONBLOCK) == 0);
  *socket_fd = fd;

  /* Use local address for test */
  sin->sin_family = AF_INET;
  sin->sin_addr.s_addr = htonl(0x7f000001);
  GPR_ASSERT(port >= 0 && port < 65536);
  sin->sin_port = htons((uint16_t)port);
}

/* Dummy gRPC callback */
void no_op_cb(void *arg, int success) {}

/* =======An upload server to test notify_on_read===========
   The server simply reads and counts a stream of bytes. */

/* An upload server. */
typedef struct {
  grpc_fd *em_fd;           /* listening fd */
  ssize_t read_bytes_total; /* total number of received bytes */
  int done;                 /* set to 1 when a server finishes serving */
  grpc_closure listen_closure;
} server;

static void server_init(server *sv) {
  sv->read_bytes_total = 0;
  sv->done = 0;
}

/* An upload session.
   Created when a new upload request arrives in the server. */
typedef struct {
  server *sv;              /* not owned by a single session */
  grpc_fd *em_fd;          /* fd to read upload bytes */
  char read_buf[BUF_SIZE]; /* buffer to store upload bytes */
  grpc_closure session_read_closure;
} session;

/* Called when an upload session can be safely shutdown.
   Close session FD and start to shutdown listen FD. */
static void session_shutdown_cb(grpc_exec_ctx *exec_ctx, void *arg, /*session */
                                bool success) {
  session *se = arg;
  server *sv = se->sv;
  grpc_fd_orphan(exec_ctx, se->em_fd, NULL, NULL, "a");
  gpr_free(se);
  /* Start to shutdown listen fd. */
  grpc_fd_shutdown(exec_ctx, sv->em_fd);
}

/* Called when data become readable in a session. */
static void session_read_cb(grpc_exec_ctx *exec_ctx, void *arg, /*session */
                            grpc_error *error) {
  session *se = arg;
  int fd = grpc_fd_wrapped_fd(se->em_fd);

  ssize_t read_once = 0;
  ssize_t read_total = 0;

  if (error != GRPC_ERROR_NONE) {
    session_shutdown_cb(exec_ctx, arg, 1);
    return;
  }

  do {
    read_once = read(fd, se->read_buf, BUF_SIZE);
    if (read_once > 0) read_total += read_once;
  } while (read_once > 0);
  se->sv->read_bytes_total += read_total;

  /* read() returns 0 to indicate the TCP connection was closed by the client.
     read(fd, read_buf, 0) also returns 0 which should never be called as such.
     It is possible to read nothing due to spurious edge event or data has
     been drained, In such a case, read() returns -1 and set errno to EAGAIN. */
  if (read_once == 0) {
    session_shutdown_cb(exec_ctx, arg, 1);
  } else if (read_once == -1) {
    if (errno == EAGAIN) {
      /* An edge triggered event is cached in the kernel until next poll.
         In the current single thread implementation, session_read_cb is called
         in the polling thread, such that polling only happens after this
         callback, and will catch read edge event if data is available again
         before notify_on_read.
         TODO(chenw): in multi-threaded version, callback and polling can be
         run in different threads. polling may catch a persist read edge event
         before notify_on_read is called.  */
      grpc_fd_notify_on_read(exec_ctx, se->em_fd, &se->session_read_closure);
    } else {
      gpr_log(GPR_ERROR, "Unhandled read error %s", strerror(errno));
      abort();
    }
  }
}

/* Called when the listen FD can be safely shutdown.
   Close listen FD and signal that server can be shutdown. */
static void listen_shutdown_cb(grpc_exec_ctx *exec_ctx, void *arg /*server */,
                               int success) {
  server *sv = arg;

  grpc_fd_orphan(exec_ctx, sv->em_fd, NULL, NULL, "b");

  gpr_mu_lock(g_mu);
  sv->done = 1;
  GPR_ASSERT(
      GRPC_LOG_IF_ERROR("pollset_kick", grpc_pollset_kick(g_pollset, NULL)));
  gpr_mu_unlock(g_mu);
}

/* Called when a new TCP connection request arrives in the listening port. */
static void listen_cb(grpc_exec_ctx *exec_ctx, void *arg, /*=sv_arg*/
                      grpc_error *error) {
  server *sv = arg;
  int fd;
  int flags;
  session *se;
  struct sockaddr_storage ss;
  socklen_t slen = sizeof(ss);
  grpc_fd *listen_em_fd = sv->em_fd;

  if (error != GRPC_ERROR_NONE) {
    listen_shutdown_cb(exec_ctx, arg, 1);
    return;
  }

  fd = accept(grpc_fd_wrapped_fd(listen_em_fd), (struct sockaddr *)&ss, &slen);
  GPR_ASSERT(fd >= 0);
  GPR_ASSERT(fd < FD_SETSIZE);
  flags = fcntl(fd, F_GETFL, 0);
  fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  se = gpr_malloc(sizeof(*se));
  se->sv = sv;
  se->em_fd = grpc_fd_create(fd, "listener");
  grpc_pollset_add_fd(exec_ctx, g_pollset, se->em_fd);
  se->session_read_closure.cb = session_read_cb;
  se->session_read_closure.cb_arg = se;
  grpc_fd_notify_on_read(exec_ctx, se->em_fd, &se->session_read_closure);

  grpc_fd_notify_on_read(exec_ctx, listen_em_fd, &sv->listen_closure);
}

/* Max number of connections pending to be accepted by listen(). */
#define MAX_NUM_FD 1024

/* Start a test server, return the TCP listening port bound to listen_fd.
   listen_cb() is registered to be interested in reading from listen_fd.
   When connection request arrives, listen_cb() is called to accept the
   connection request. */
static int server_start(grpc_exec_ctx *exec_ctx, server *sv) {
  int port = 0;
  int fd;
  struct sockaddr_in sin;
  socklen_t addr_len;

  create_test_socket(port, &fd, &sin);
  addr_len = sizeof(sin);
  GPR_ASSERT(bind(fd, (struct sockaddr *)&sin, addr_len) == 0);
  GPR_ASSERT(getsockname(fd, (struct sockaddr *)&sin, &addr_len) == 0);
  port = ntohs(sin.sin_port);
  GPR_ASSERT(listen(fd, MAX_NUM_FD) == 0);

  sv->em_fd = grpc_fd_create(fd, "server");
  grpc_pollset_add_fd(exec_ctx, g_pollset, sv->em_fd);
  /* Register to be interested in reading from listen_fd. */
  sv->listen_closure.cb = listen_cb;
  sv->listen_closure.cb_arg = sv;
  grpc_fd_notify_on_read(exec_ctx, sv->em_fd, &sv->listen_closure);

  return port;
}

/* Wait and shutdown a sever. */
static void server_wait_and_shutdown(server *sv) {
  gpr_mu_lock(g_mu);
  while (!sv->done) {
    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
    grpc_pollset_worker *worker = NULL;
    GPR_ASSERT(GRPC_LOG_IF_ERROR(
        "pollset_work",
        grpc_pollset_work(&exec_ctx, g_pollset, &worker,
                          gpr_now(GPR_CLOCK_MONOTONIC),
                          gpr_inf_future(GPR_CLOCK_MONOTONIC))));
    gpr_mu_unlock(g_mu);
    grpc_exec_ctx_finish(&exec_ctx);
    gpr_mu_lock(g_mu);
  }
  gpr_mu_unlock(g_mu);
}

/* ===An upload client to test notify_on_write=== */

/* Client write buffer size */
#define CLIENT_WRITE_BUF_SIZE 10
/* Total number of times that the client fills up the write buffer */
#define CLIENT_TOTAL_WRITE_CNT 3

/* An upload client. */
typedef struct {
  grpc_fd *em_fd;
  char write_buf[CLIENT_WRITE_BUF_SIZE];
  ssize_t write_bytes_total;
  /* Number of times that the client fills up the write buffer and calls
     notify_on_write to schedule another write. */
  int client_write_cnt;

  int done; /* set to 1 when a client finishes sending */
  grpc_closure write_closure;
} client;

static void client_init(client *cl) {
  memset(cl->write_buf, 0, sizeof(cl->write_buf));
  cl->write_bytes_total = 0;
  cl->client_write_cnt = 0;
  cl->done = 0;
}

/* Called when a client upload session is ready to shutdown. */
static void client_session_shutdown_cb(grpc_exec_ctx *exec_ctx,
                                       void *arg /*client */, int success) {
  client *cl = arg;
  grpc_fd_orphan(exec_ctx, cl->em_fd, NULL, NULL, "c");
  cl->done = 1;
  GPR_ASSERT(
      GRPC_LOG_IF_ERROR("pollset_kick", grpc_pollset_kick(g_pollset, NULL)));
}

/* Write as much as possible, then register notify_on_write. */
static void client_session_write(grpc_exec_ctx *exec_ctx, void *arg, /*client */
                                 grpc_error *error) {
  client *cl = arg;
  int fd = grpc_fd_wrapped_fd(cl->em_fd);
  ssize_t write_once = 0;

  if (error != GRPC_ERROR_NONE) {
    gpr_mu_lock(g_mu);
    client_session_shutdown_cb(exec_ctx, arg, 1);
    gpr_mu_unlock(g_mu);
    return;
  }

  do {
    write_once = write(fd, cl->write_buf, CLIENT_WRITE_BUF_SIZE);
    if (write_once > 0) cl->write_bytes_total += write_once;
  } while (write_once > 0);

  if (errno == EAGAIN) {
    gpr_mu_lock(g_mu);
    if (cl->client_write_cnt < CLIENT_TOTAL_WRITE_CNT) {
      cl->write_closure.cb = client_session_write;
      cl->write_closure.cb_arg = cl;
      grpc_fd_notify_on_write(exec_ctx, cl->em_fd, &cl->write_closure);
      cl->client_write_cnt++;
    } else {
      client_session_shutdown_cb(exec_ctx, arg, 1);
    }
    gpr_mu_unlock(g_mu);
  } else {
    gpr_log(GPR_ERROR, "unknown errno %s", strerror(errno));
    abort();
  }
}

/* Start a client to send a stream of bytes. */
static void client_start(grpc_exec_ctx *exec_ctx, client *cl, int port) {
  int fd;
  struct sockaddr_in sin;
  create_test_socket(port, &fd, &sin);
  if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)) == -1) {
    if (errno == EINPROGRESS) {
      struct pollfd pfd;
      pfd.fd = fd;
      pfd.events = POLLOUT;
      pfd.revents = 0;
      if (poll(&pfd, 1, -1) == -1) {
        gpr_log(GPR_ERROR, "poll() failed during connect; errno=%d", errno);
        abort();
      }
    } else {
      gpr_log(GPR_ERROR, "Failed to connect to the server (errno=%d)", errno);
      abort();
    }
  }

  cl->em_fd = grpc_fd_create(fd, "client");
  grpc_pollset_add_fd(exec_ctx, g_pollset, cl->em_fd);

  client_session_write(exec_ctx, cl, GRPC_ERROR_NONE);
}

/* Wait for the signal to shutdown a client. */
static void client_wait_and_shutdown(client *cl) {
  gpr_mu_lock(g_mu);
  while (!cl->done) {
    grpc_pollset_worker *worker = NULL;
    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
    GPR_ASSERT(GRPC_LOG_IF_ERROR(
        "pollset_work",
        grpc_pollset_work(&exec_ctx, g_pollset, &worker,
                          gpr_now(GPR_CLOCK_MONOTONIC),
                          gpr_inf_future(GPR_CLOCK_MONOTONIC))));
    gpr_mu_unlock(g_mu);
    grpc_exec_ctx_finish(&exec_ctx);
    gpr_mu_lock(g_mu);
  }
  gpr_mu_unlock(g_mu);
}

/* Test grpc_fd. Start an upload server and client, upload a stream of
   bytes from the client to the server, and verify that the total number of
   sent bytes is equal to the total number of received bytes. */
static void test_grpc_fd(void) {
  server sv;
  client cl;
  int port;
  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;

  server_init(&sv);
  port = server_start(&exec_ctx, &sv);
  client_init(&cl);
  client_start(&exec_ctx, &cl, port);
  grpc_exec_ctx_finish(&exec_ctx);
  client_wait_and_shutdown(&cl);
  server_wait_and_shutdown(&sv);
  GPR_ASSERT(sv.read_bytes_total == cl.write_bytes_total);
  gpr_log(GPR_INFO, "Total read bytes %" PRIdPTR, sv.read_bytes_total);
}

typedef struct fd_change_data {
  grpc_iomgr_cb_func cb_that_ran;
} fd_change_data;

void init_change_data(fd_change_data *fdc) { fdc->cb_that_ran = NULL; }

void destroy_change_data(fd_change_data *fdc) {}

static void first_read_callback(grpc_exec_ctx *exec_ctx,
                                void *arg /* fd_change_data */,
                                grpc_error *error) {
  fd_change_data *fdc = arg;

  gpr_mu_lock(g_mu);
  fdc->cb_that_ran = first_read_callback;
  GPR_ASSERT(
      GRPC_LOG_IF_ERROR("pollset_kick", grpc_pollset_kick(g_pollset, NULL)));
  gpr_mu_unlock(g_mu);
}

static void second_read_callback(grpc_exec_ctx *exec_ctx,
                                 void *arg /* fd_change_data */,
                                 grpc_error *error) {
  fd_change_data *fdc = arg;

  gpr_mu_lock(g_mu);
  fdc->cb_that_ran = second_read_callback;
  GPR_ASSERT(
      GRPC_LOG_IF_ERROR("pollset_kick", grpc_pollset_kick(g_pollset, NULL)));
  gpr_mu_unlock(g_mu);
}

/* Test that changing the callback we use for notify_on_read actually works.
   Note that we have two different but almost identical callbacks above -- the
   point is to have two different function pointers and two different data
   pointers and make sure that changing both really works. */
static void test_grpc_fd_change(void) {
  grpc_fd *em_fd;
  fd_change_data a, b;
  int flags;
  int sv[2];
  char data;
  ssize_t result;
  grpc_closure first_closure;
  grpc_closure second_closure;
  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;

  first_closure.cb = first_read_callback;
  first_closure.cb_arg = &a;
  second_closure.cb = second_read_callback;
  second_closure.cb_arg = &b;

  init_change_data(&a);
  init_change_data(&b);

  GPR_ASSERT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == 0);
  flags = fcntl(sv[0], F_GETFL, 0);
  GPR_ASSERT(fcntl(sv[0], F_SETFL, flags | O_NONBLOCK) == 0);
  flags = fcntl(sv[1], F_GETFL, 0);
  GPR_ASSERT(fcntl(sv[1], F_SETFL, flags | O_NONBLOCK) == 0);

  em_fd = grpc_fd_create(sv[0], "test_grpc_fd_change");
  grpc_pollset_add_fd(&exec_ctx, g_pollset, em_fd);

  /* Register the first callback, then make its FD readable */
  grpc_fd_notify_on_read(&exec_ctx, em_fd, &first_closure);
  data = 0;
  result = write(sv[1], &data, 1);
  GPR_ASSERT(result == 1);

  /* And now wait for it to run. */
  gpr_mu_lock(g_mu);
  while (a.cb_that_ran == NULL) {
    grpc_pollset_worker *worker = NULL;
    GPR_ASSERT(GRPC_LOG_IF_ERROR(
        "pollset_work",
        grpc_pollset_work(&exec_ctx, g_pollset, &worker,
                          gpr_now(GPR_CLOCK_MONOTONIC),
                          gpr_inf_future(GPR_CLOCK_MONOTONIC))));
    gpr_mu_unlock(g_mu);
    grpc_exec_ctx_finish(&exec_ctx);
    gpr_mu_lock(g_mu);
  }
  GPR_ASSERT(a.cb_that_ran == first_read_callback);
  gpr_mu_unlock(g_mu);

  /* And drain the socket so we can generate a new read edge */
  result = read(sv[0], &data, 1);
  GPR_ASSERT(result == 1);

  /* Now register a second callback with distinct change data, and do the same
     thing again. */
  grpc_fd_notify_on_read(&exec_ctx, em_fd, &second_closure);
  data = 0;
  result = write(sv[1], &data, 1);
  GPR_ASSERT(result == 1);

  gpr_mu_lock(g_mu);
  while (b.cb_that_ran == NULL) {
    grpc_pollset_worker *worker = NULL;
    GPR_ASSERT(GRPC_LOG_IF_ERROR(
        "pollset_work",
        grpc_pollset_work(&exec_ctx, g_pollset, &worker,
                          gpr_now(GPR_CLOCK_MONOTONIC),
                          gpr_inf_future(GPR_CLOCK_MONOTONIC))));
    gpr_mu_unlock(g_mu);
    grpc_exec_ctx_finish(&exec_ctx);
    gpr_mu_lock(g_mu);
  }
  /* Except now we verify that second_read_callback ran instead */
  GPR_ASSERT(b.cb_that_ran == second_read_callback);
  gpr_mu_unlock(g_mu);

  grpc_fd_orphan(&exec_ctx, em_fd, NULL, NULL, "d");
  grpc_exec_ctx_finish(&exec_ctx);
  destroy_change_data(&a);
  destroy_change_data(&b);
  close(sv[1]);
}

static void destroy_pollset(grpc_exec_ctx *exec_ctx, void *p,
                            grpc_error *error) {
  grpc_pollset_destroy(p);
}

int main(int argc, char **argv) {
  grpc_closure destroyed;
  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
  grpc_test_init(argc, argv);
  grpc_iomgr_init();
  g_pollset = gpr_malloc(grpc_pollset_size());
  grpc_pollset_init(g_pollset, &g_mu);
  test_grpc_fd();
  test_grpc_fd_change();
  grpc_closure_init(&destroyed, destroy_pollset, g_pollset);
  grpc_pollset_shutdown(&exec_ctx, g_pollset, &destroyed);
  grpc_exec_ctx_finish(&exec_ctx);
  gpr_free(g_pollset);
  grpc_iomgr_shutdown();
  return 0;
}