multi: add curl_multi_wakeup()

This commit adds curl_multi_wakeup() which was previously in the TODO
list under the curl_multi_unblock name.

On some platforms and with some configurations this feature might not be
available or can fail, in these cases a new error code
(CURLM_WAKEUP_FAILURE) is returned from curl_multi_wakeup().

Fixes #4418
Closes #4608

9 files changed, 485 insertions, 3 deletions

diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index 23215655b..c45bced5b 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -179,7 +179,7 @@ test1525 test1526 test1527 test1528 test1529 test1530 test1531 test1532 \
 test1533 test1534 test1535 test1536 test1537 test1538 \
 test1540 test1541 \
 test1550 test1551 test1552 test1553 test1554 test1555 test1556 test1557 \
-test1558 test1559 test1560 test1561 test1562 test1563 \
+test1558 test1559 test1560 test1561 test1562 test1563 test1564 test1565 \
 \
 test1590 test1591 test1592 test1593 test1594 test1595 test1596 \
 \
diff --git a/tests/data/test1135 b/tests/data/test1135
index eca6860fb..37a55427f 100644
--- a/tests/data/test1135
+++ b/tests/data/test1135
@@ -92,6 +92,7 @@ CURL_EXTERN CURLMcode curl_multi_remove_handle(CURLM *multi_handle,
 CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
 CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
 CURL_EXTERN CURLMcode curl_multi_poll(CURLM *multi_handle,
+CURL_EXTERN CURLMcode curl_multi_wakeup(CURLM *multi_handle);
 CURL_EXTERN CURLMcode curl_multi_perform(CURLM *multi_handle,
 CURL_EXTERN CURLMcode curl_multi_cleanup(CURLM *multi_handle);
 CURL_EXTERN CURLMsg *curl_multi_info_read(CURLM *multi_handle,
diff --git a/tests/data/test1538 b/tests/data/test1538
index 36f53040b..3b22ebc27 100644
--- a/tests/data/test1538
+++ b/tests/data/test1538
@@ -139,7 +139,8 @@ m5: Invalid socket argument
 m6: Unknown option
 m7: The easy handle is already added to a multi handle
 m8: API function called from within callback
-m9: Unknown error
+m9: Wakeup is unavailable or failed
+m10: Unknown error
 s0: No error
 s1: Unknown share option
 s2: Share currently in use
diff --git a/tests/data/test1564 b/tests/data/test1564
new file mode 100644
index 000000000..279665bd1
--- /dev/null
+++ b/tests/data/test1564
@@ -0,0 +1,31 @@
+<testcase>
+<info>
+<keywords>
+multi
+wakeup
+</keywords>
+</info>
+
+# Server-side
+<reply>
+</reply>
+
+# Client-side
+<client>
+<server>
+none
+</server>
+<tool>
+lib1564
+</tool>
+<name>
+wakeup before poll with no easy handles
+</name>
+<command>
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+</verify>
+</testcase>
diff --git a/tests/data/test1565 b/tests/data/test1565
new file mode 100644
index 000000000..f554e0f34
--- /dev/null
+++ b/tests/data/test1565
@@ -0,0 +1,41 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+multi
+multi-threaded
+wakeup
+</keywords>
+</info>
+
+# Server-side
+<reply>
+<data nocheck="yes">
+HTTP/1.1 200 OK
+Content-Length: 3
+
+OK
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+<tool>
+lib1565
+</tool>
+<name>
+wakeup from another thread
+</name>
+<command>
+http://%HOSTIP:%HTTPPORT/1
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+</verify>
+</testcase>
diff --git a/tests/libtest/Makefile.inc b/tests/libtest/Makefile.inc
index 9ba72d7de..374a66747 100644
--- a/tests/libtest/Makefile.inc
+++ b/tests/libtest/Makefile.inc
@@ -31,7 +31,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect                \
  lib1534 lib1535 lib1536 lib1537 lib1538 \
  lib1540 lib1541 \
  lib1550 lib1551 lib1552 lib1553 lib1554 lib1555 lib1556 lib1557 \
- lib1558 lib1559 lib1560 \
+ lib1558 lib1559 lib1560 lib1564 lib1565 \
  lib1591 lib1592 lib1593 lib1594 lib1596 \
  lib1900 lib1905 lib1906 lib1907 \
  lib2033
@@ -536,6 +536,14 @@ lib1559_LDADD = $(TESTUTIL_LIBS)
 lib1560_SOURCES = lib1560.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1560_LDADD = $(TESTUTIL_LIBS)
 
+lib1564_SOURCES = lib1564.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1564_LDADD = $(TESTUTIL_LIBS)
+lib1564_CPPFLAGS = $(AM_CPPFLAGS)
+
+lib1565_SOURCES = lib1565.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1565_LDADD = $(TESTUTIL_LIBS)
+lib1565_CPPFLAGS = $(AM_CPPFLAGS)
+
 lib1591_SOURCES = lib1591.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1591_LDADD = $(TESTUTIL_LIBS)
 lib1591_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1591
diff --git a/tests/libtest/lib1564.c b/tests/libtest/lib1564.c
new file mode 100644
index 000000000..225c8c6d7
--- /dev/null
+++ b/tests/libtest/lib1564.c
@@ -0,0 +1,142 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "test.h"
+
+#include "testutil.h"
+#include "warnless.h"
+#include "memdebug.h"
+
+#define TEST_HANG_TIMEOUT 60 * 1000
+#define WAKEUP_NUM 1234567
+
+int test(char *URL)
+{
+  CURLM *multi = NULL;
+  int numfds;
+  int i;
+  int res = 0;
+  struct timeval time_before_wait, time_after_wait;
+
+  (void)URL;
+
+  start_test_timing();
+
+  global_init(CURL_GLOBAL_ALL);
+
+  multi_init(multi);
+
+  /* no wakeup */
+
+  time_before_wait = tutil_tvnow();
+  multi_poll(multi, NULL, 0, 1000, &numfds);
+  time_after_wait = tutil_tvnow();
+
+  if(tutil_tvdiff(time_after_wait, time_before_wait) < 500) {
+    fprintf(stderr, "%s:%d curl_multi_poll returned too early\n",
+            __FILE__, __LINE__);
+    res = TEST_ERR_MAJOR_BAD;
+    goto test_cleanup;
+  }
+
+  abort_on_test_timeout();
+
+  /* try a single wakeup */
+
+  multi_wakeup(multi);
+
+  time_before_wait = tutil_tvnow();
+  multi_poll(multi, NULL, 0, 1000, &numfds);
+  time_after_wait = tutil_tvnow();
+
+  if(tutil_tvdiff(time_after_wait, time_before_wait) > 500) {
+    fprintf(stderr, "%s:%d curl_multi_poll returned too late\n",
+            __FILE__, __LINE__);
+    res = TEST_ERR_MAJOR_BAD;
+    goto test_cleanup;
+  }
+
+  abort_on_test_timeout();
+
+  /* previous wakeup should not wake up this */
+
+  time_before_wait = tutil_tvnow();
+  multi_poll(multi, NULL, 0, 1000, &numfds);
+  time_after_wait = tutil_tvnow();
+
+  if(tutil_tvdiff(time_after_wait, time_before_wait) < 500) {
+    fprintf(stderr, "%s:%d curl_multi_poll returned too early\n",
+            __FILE__, __LINE__);
+    res = TEST_ERR_MAJOR_BAD;
+    goto test_cleanup;
+  }
+
+  abort_on_test_timeout();
+
+  /* try lots of wakeup */
+
+  for(i = 0; i < WAKEUP_NUM; ++i)
+    multi_wakeup(multi);
+
+  time_before_wait = tutil_tvnow();
+  multi_poll(multi, NULL, 0, 1000, &numfds);
+  time_after_wait = tutil_tvnow();
+
+  if(tutil_tvdiff(time_after_wait, time_before_wait) > 500) {
+    fprintf(stderr, "%s:%d curl_multi_poll returned too late\n",
+            __FILE__, __LINE__);
+    res = TEST_ERR_MAJOR_BAD;
+    goto test_cleanup;
+  }
+
+  abort_on_test_timeout();
+
+#if !defined(WIN32) && !defined(_WIN32) && !defined(__WIN32__) \
+    && !defined(__CYGWIN__)
+  /* Even lots of previous wakeups should not wake up this.
+
+     On Windows (particularly when using MinGW), the socketpair
+     used for curl_multi_wakeup() is really asynchronous,
+     meaning when it's called a lot, it can take some time
+     before all of the data can be read. Sometimes it can wake
+     up more than one curl_multi_poll() call. */
+
+  time_before_wait = tutil_tvnow();
+  multi_poll(multi, NULL, 0, 1000, &numfds);
+  time_after_wait = tutil_tvnow();
+
+  if(tutil_tvdiff(time_after_wait, time_before_wait) < 500) {
+    fprintf(stderr, "%s:%d curl_multi_poll returned too early\n",
+            __FILE__, __LINE__);
+    res = TEST_ERR_MAJOR_BAD;
+    goto test_cleanup;
+  }
+
+  abort_on_test_timeout();
+#endif
+
+test_cleanup:
+
+  curl_multi_cleanup(multi);
+  curl_global_cleanup();
+
+  return res;
+}
diff --git a/tests/libtest/lib1565.c b/tests/libtest/lib1565.c
new file mode 100644
index 000000000..b2fa40aaa
--- /dev/null
+++ b/tests/libtest/lib1565.c
@@ -0,0 +1,204 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "test.h"
+
+#include "testutil.h"
+#include "warnless.h"
+#include "memdebug.h"
+
+#ifdef HAVE_PTHREAD_H
+#include <pthread.h>
+#include <unistd.h>
+
+#define TEST_HANG_TIMEOUT 60 * 1000
+#define CONN_NUM 3
+#define TIME_BETWEEN_START_SECS 2
+
+static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+static CURL *pending_handles[CONN_NUM];
+static int pending_num = 0;
+static int test_failure = 0;
+
+static CURLM *multi = NULL;
+static const char *url;
+
+static void *run_thread(void *ptr)
+{
+  CURL *easy = NULL;
+  int res = 0;
+  int i;
+
+  (void)ptr;
+
+  for(i = 0; i < CONN_NUM; i++) {
+    sleep(TIME_BETWEEN_START_SECS);
+
+    easy_init(easy);
+
+    easy_setopt(easy, CURLOPT_URL, url);
+    easy_setopt(easy, CURLOPT_VERBOSE, 0L);
+
+    pthread_mutex_lock(&lock);
+
+    if(test_failure) {
+      pthread_mutex_unlock(&lock);
+      goto test_cleanup;
+    }
+
+    pending_handles[pending_num] = easy;
+    pending_num++;
+    easy = NULL;
+
+    pthread_mutex_unlock(&lock);
+
+    multi_wakeup(multi);
+  }
+
+test_cleanup:
+
+  curl_easy_cleanup(easy);
+
+  pthread_mutex_lock(&lock);
+
+  if(!test_failure)
+    test_failure = res;
+
+  pthread_mutex_unlock(&lock);
+
+  return NULL;
+}
+
+int test(char *URL)
+{
+  int still_running;
+  int num;
+  int i;
+  int res = 0;
+  CURL *started_handles[CONN_NUM];
+  int started_num = 0;
+  int finished_num = 0;
+  pthread_t tid = 0;
+  struct CURLMsg *message;
+
+  start_test_timing();
+
+  global_init(CURL_GLOBAL_ALL);
+
+  multi_init(multi);
+
+  url = URL;
+
+  res = pthread_create(&tid, NULL, run_thread, NULL);
+  if(0 != res) {
+    fprintf(stderr, "%s:%d Couldn't create thread, errno %d\n",
+            __FILE__, __LINE__, res);
+    goto test_cleanup;
+  }
+
+  while(1) {
+    multi_perform(multi, &still_running);
+
+    abort_on_test_timeout();
+
+    while((message = curl_multi_info_read(multi, &num)) != NULL) {
+      if(message->msg == CURLMSG_DONE) {
+        res = message->data.result;
+        if(res)
+          goto test_cleanup;
+        multi_remove_handle(multi, message->easy_handle);
+        finished_num++;
+      }
+      else {
+        fprintf(stderr, "%s:%d Got an unexpected message from curl: %i\n",
+              __FILE__, __LINE__, (int)message->msg);
+        res = TEST_ERR_MAJOR_BAD;
+        goto test_cleanup;
+      }
+
+      abort_on_test_timeout();
+    }
+
+    if(CONN_NUM == finished_num)
+      break;
+
+    multi_poll(multi, NULL, 0, TEST_HANG_TIMEOUT, &num);
+
+    abort_on_test_timeout();
+
+    pthread_mutex_lock(&lock);
+
+    while(pending_num > 0) {
+      res_multi_add_handle(multi, pending_handles[pending_num - 1]);
+      if(res) {
+        pthread_mutex_unlock(&lock);
+        goto test_cleanup;
+      }
+
+      started_handles[started_num] = pending_handles[pending_num - 1];
+      started_num++;
+      pending_num--;
+    }
+
+    pthread_mutex_unlock(&lock);
+
+    abort_on_test_timeout();
+  }
+
+  if(CONN_NUM != started_num) {
+    fprintf(stderr, "%s:%d Not all connections started: %d of %d\n",
+            __FILE__, __LINE__, started_num, CONN_NUM);
+    goto test_cleanup;
+  }
+
+  if(CONN_NUM != finished_num) {
+    fprintf(stderr, "%s:%d Not all connections finished: %d of %d\n",
+            __FILE__, __LINE__, started_num, CONN_NUM);
+    goto test_cleanup;
+  }
+
+test_cleanup:
+
+  pthread_mutex_lock(&lock);
+  if(!test_failure)
+    test_failure = res;
+  pthread_mutex_unlock(&lock);
+
+  if(0 != tid)
+    pthread_join(tid, NULL);
+
+  curl_multi_cleanup(multi);
+  for(i = 0; i < pending_num; i++)
+    curl_easy_cleanup(pending_handles[i]);
+  for(i = 0; i < started_num; i++)
+    curl_easy_cleanup(started_handles[i]);
+  curl_global_cleanup();
+
+  return test_failure;
+}
+
+#else /* without pthread, this test doesn't work */
+int test(char *URL)
+{
+  (void)URL;
+  return 0;
+}
+#endif
diff --git a/tests/libtest/test.h b/tests/libtest/test.h
index bb1acca0e..3c8323de4 100644
--- a/tests/libtest/test.h
+++ b/tests/libtest/test.h
@@ -355,6 +355,60 @@ extern int unitfail;
 
 /* ---------------------------------------------------------------- */
 
+#define exe_multi_poll(A,B,C,D,E,Y,Z) do {                          \
+  CURLMcode ec;                                                     \
+  if((ec = curl_multi_poll((A), (B), (C), (D), (E))) != CURLM_OK) { \
+    fprintf(stderr, "%s:%d curl_multi_poll() failed, "              \
+            "with code %d (%s)\n",                                  \
+            (Y), (Z), (int)ec, curl_multi_strerror(ec));            \
+    res = (int)ec;                                                  \
+  }                                                                 \
+  else if(*((E)) < 0) {                                             \
+    fprintf(stderr, "%s:%d curl_multi_poll() succeeded, "           \
+            "but returned invalid numfds value (%d)\n",             \
+            (Y), (Z), (int)*((E)));                                 \
+    res = TEST_ERR_NUM_HANDLES;                                     \
+  }                                                                 \
+} WHILE_FALSE
+
+#define res_multi_poll(A, B, C, D, E) \
+  exe_multi_poll((A), (B), (C), (D), (E), (__FILE__), (__LINE__))
+
+#define chk_multi_poll(A, B, C, D, E, Y, Z) do {     \
+  exe_multi_poll((A), (B), (C), (D), (E), (Y), (Z)); \
+  if(res)                                            \
+    goto test_cleanup;                               \
+} WHILE_FALSE
+
+#define multi_poll(A, B, C, D, E) \
+  chk_multi_poll((A), (B), (C), (D), (E), (__FILE__), (__LINE__))
+
+/* ---------------------------------------------------------------- */
+
+#define exe_multi_wakeup(A,Y,Z) do {                     \
+  CURLMcode ec;                                          \
+  if((ec = curl_multi_wakeup((A))) != CURLM_OK) {        \
+    fprintf(stderr, "%s:%d curl_multi_wakeup() failed, " \
+            "with code %d (%s)\n",                       \
+            (Y), (Z), (int)ec, curl_multi_strerror(ec)); \
+    res = (int)ec;                                       \
+  }                                                      \
+} WHILE_FALSE
+
+#define res_multi_wakeup(A) \
+  exe_multi_wakeup((A), (__FILE__), (__LINE__))
+
+#define chk_multi_wakeup(A, Y, Z) do { \
+  exe_multi_wakeup((A), (Y), (Z));     \
+  if(res)                              \
+    goto test_cleanup;                 \
+} WHILE_FALSE
+
+#define multi_wakeup(A) \
+  chk_multi_wakeup((A), (__FILE__), (__LINE__))
+
+/* ---------------------------------------------------------------- */
+
 #define exe_select_test(A, B, C, D, E, Y, Z) do {               \
     int ec;                                                     \
     if(select_wrapper((A), (B), (C), (D), (E)) == -1) {         \