1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24 /*
25 * See https://github.com/curl/curl/issues/3371
26 *
27 * This test case checks whether curl_multi_remove_handle() cancels
28 * asynchronous DNS resolvers without blocking where possible. Obviously, it
29 * only tests whichever resolver cURL is actually built with.
30 */
31
32 /* We're willing to wait a very generous two seconds for the removal. This is
33 as low as we can go while still easily supporting SIGALRM timing for the
34 non-threaded blocking resolver. It doesn't matter that much because when
35 the test passes, we never wait this long. We set it much higher to avoid
36 issues when running on overloaded CI machines. */
37 #define TEST_HANG_TIMEOUT 60 * 1000
38
39 #include "test.h"
40 #include "testutil.h"
41
42 #include <sys/stat.h>
43
test(char * URL)44 CURLcode test(char *URL)
45 {
46 int stillRunning;
47 CURLM *multiHandle = NULL;
48 CURL *curl = NULL;
49 CURLcode res = CURLE_OK;
50 CURLMcode mres;
51 int timeout;
52
53 global_init(CURL_GLOBAL_ALL);
54
55 multi_init(multiHandle);
56
57 easy_init(curl);
58
59 easy_setopt(curl, CURLOPT_VERBOSE, 1L);
60 easy_setopt(curl, CURLOPT_URL, URL);
61
62 /* Set a DNS server that hopefully will not respond when using c-ares. */
63 if(curl_easy_setopt(curl, CURLOPT_DNS_SERVERS, "0.0.0.0") == CURLE_OK)
64 /* Since we could set the DNS server, presume we are working with a
65 resolver that can be cancelled (i.e. c-ares). Thus,
66 curl_multi_remove_handle() should not block even when the resolver
67 request is outstanding. So, set a request timeout _longer_ than the
68 test hang timeout so we will fail if the handle removal call incorrectly
69 blocks. */
70 timeout = TEST_HANG_TIMEOUT * 2;
71 else {
72 /* If we can't set the DNS server, presume that we are configured to use a
73 resolver that can't be cancelled (i.e. the threaded resolver or the
74 non-threaded blocking resolver). So, we just test that the
75 curl_multi_remove_handle() call does finish well within our test
76 timeout.
77
78 But, it is very unlikely that the resolver request will take any time at
79 all because we haven't been able to configure the resolver to use an
80 non-responsive DNS server. At least we exercise the flow.
81 */
82 fprintf(stderr,
83 "CURLOPT_DNS_SERVERS not supported; "
84 "assuming curl_multi_remove_handle() will block\n");
85 timeout = TEST_HANG_TIMEOUT / 2;
86 }
87
88 /* Setting a timeout on the request should ensure that even if we have to
89 wait for the resolver during curl_multi_remove_handle(), it won't take
90 longer than this, because the resolver request inherits its timeout from
91 this. */
92 easy_setopt(curl, CURLOPT_TIMEOUT_MS, timeout);
93
94 multi_add_handle(multiHandle, curl);
95
96 /* This should move the handle from INIT => CONNECT => WAITRESOLVE. */
97 fprintf(stderr, "curl_multi_perform()...\n");
98 multi_perform(multiHandle, &stillRunning);
99 fprintf(stderr, "curl_multi_perform() succeeded\n");
100
101 /* Start measuring how long it takes to remove the handle. */
102 fprintf(stderr, "curl_multi_remove_handle()...\n");
103 start_test_timing();
104 mres = curl_multi_remove_handle(multiHandle, curl);
105 if(mres) {
106 fprintf(stderr, "curl_multi_remove_handle() failed, with code %d\n", mres);
107 res = TEST_ERR_MULTI;
108 goto test_cleanup;
109 }
110 fprintf(stderr, "curl_multi_remove_handle() succeeded\n");
111
112 /* Fail the test if it took too long to remove. This happens after the fact,
113 and says "it seems that it would have run forever", which isn't true, but
114 it's close enough, and simple to do. */
115 abort_on_test_timeout();
116
117 test_cleanup:
118 curl_easy_cleanup(curl);
119 curl_multi_cleanup(multiHandle);
120 curl_global_cleanup();
121
122 return res;
123 }
124
