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c2fe4e58ad
curlhttpsrc uses a single thread running the gst_curl_http_src_curl_multi_loop() function to handle receiving data and messages from libcurl. Each instance of curlhttpsrc adds an entry into a queue in GstCurlHttpSrcMultiTaskContext and waits for the multi_loop to perform the HTTP request. Valgrind has shown up race conditions and memory leaks: 1. gst_curl_http_src_change_state() does not wait for the multi_loop to complete before going to the NULL state, which means that an instance of GstCurlHttpSrc can be released while gst_curl_http_src_curl_multi_loop() still has a reference to it. 2. if multiple elements try to be removed from the queue at once, only the last one is deleted. 3. source->caps is leaked 4. curl multi_handle is leaked 5. leak of curl_handle if URI not set 6. leak of http_headers when reusing element 7. null pointer dereference in negotiate caps 8. double-free of the default user-agent string 9. leak of multi_task_context.task This commit changes the logic so that each element has a connection status, which is used by the multi_loop to decide when to remove an element from its queue. An instance of curlhttpsrc will not enter the NULL state until its reference has been removed from the queue. When shutting down the curl multi loop, the memory allocated from the call to curl_multi_init() is now released. When gstadaptivedemux uses a URI source element, it will re-use it for multiple requests, moving it between READY and PLAYING between each request. curlhttpsrc was leaking the http_headers structure in this use case. The gst_curl_http_src_negotiate_caps() function extracts the "response-headers" field from the http_headers, but did not check that this field might be NULL. If the user-agent property is set, the global user-agent string was freed. This caused a double-free error if the user-agent is ever set a second time during the execution of the process. There are situations within curlhttpsrc where the code needs both the global multi_task_context mutex and the per-element buffer_mutex. To avoid deadlocks, it is vital that the order in which these are requested is always the same. This commit modifies the locking order to always be in the order: 1. multi_task_context.task_rec_mutex 2. buffer_mutex Fixes #876
66 lines
2.7 KiB
C
66 lines
2.7 KiB
C
/*
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* GstCurlHttpSrc
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* Copyright 2017 British Broadcasting Corporation - Research and Development
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*
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* Author: Sam Hurst <samuelh@rd.bbc.co.uk>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* Alternatively, the contents of this file may be used under the
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* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
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* which case the following provisions apply instead of the ones
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* mentioned above:
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifndef GSTCURLQUEUE_H_
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#define GSTCURLQUEUE_H_
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#include "gstcurlhttpsrc.h"
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struct _GstCurlHttpSrcQueueElement
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{
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GstCurlHttpSrc *p;
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volatile gint running;
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GstCurlHttpSrcQueueElement *next;
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};
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gboolean gst_curl_http_src_add_queue_item (GstCurlHttpSrcQueueElement **queue,
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GstCurlHttpSrc *s);
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gboolean gst_curl_http_src_remove_queue_item (
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GstCurlHttpSrcQueueElement **queue, GstCurlHttpSrc *s);
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gboolean gst_curl_http_src_remove_queue_handle (
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GstCurlHttpSrcQueueElement **queue, CURL *handle, CURLcode result);
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#endif /* GSTCURLQUEUE_H_ */
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