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c1e5258497
After PR #1498 added read locking to channelstorage_cpp_map_name_id, if ARI channels/externalMedia was called with a custom channel id AND the cpp_map_name_id channel storage backend is in use, a deadlock can occur when hanging up the channel. It's actually triggered in channel.c:__ast_channel_alloc_ap() when it gets a write lock on the channelstorage driver then subsequently does a lookup for channel uniqueid which now does a read lock. This is an invalid operation and causes the lock state to get "bad". When the channels try to hang up, a write lock is attempted again which hangs and causes the deadlock. Now instead of the cpp_map_name_id channelstorage driver "get" APIs automatically performing a read lock, they take a "lock" parameter which allows a caller who already has a write lock to indicate that the "get" API must not attempt its own lock. This prevents the state from getting mesed up. The ao2_legacy driver uses the ao2 container's recursive mutex so doesn't have this issue but since it also implements the common channelstorage API, it needed its "get" implementations updated to take the lock parameter. They just don't use it. Resolves: #1578
99 lines
4.3 KiB
C
99 lines
4.3 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2024, Sangoma Technologies Corporation
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*
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* George Joseph <gjoseph@sangoma.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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#ifndef CHANNELSTORAGE_H_
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#define CHANNELSTORAGE_H_
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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#include "asterisk.h"
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#include "asterisk/channel.h"
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#include "asterisk/channel_internal.h"
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#define AST_CHANNELSTORAGE_DEFAULT_TYPE "ao2_legacy"
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struct ast_channelstorage_driver {
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const char *driver_name;
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struct ast_channelstorage_instance* (*open_instance)(const char *instance_name);
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};
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int ast_channelstorage_register_driver(
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const struct ast_channelstorage_driver *driver_name);
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const struct ast_channelstorage_driver *ast_channelstorage_get_driver(
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const char *driver_name);
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struct ast_channelstorage_driver_pvt;
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struct ast_channelstorage_instance {
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struct ast_channelstorage_driver_pvt *handle;
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void *lock_handle;
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void (*close_instance)(struct ast_channelstorage_instance *driver);
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int (*insert)(struct ast_channelstorage_instance *driver, struct ast_channel *chan, int flags, int lock);
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int (*remove)(struct ast_channelstorage_instance *driver, struct ast_channel *chan, int lock);
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void (*rdlock)(struct ast_channelstorage_instance *driver);
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void (*wrlock)(struct ast_channelstorage_instance *driver);
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void (*unlock)(struct ast_channelstorage_instance *driver);
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int (*active_channels)(struct ast_channelstorage_instance *driver, int rdlock);
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struct ast_channel *(*callback)(struct ast_channelstorage_instance *driver, ao2_callback_data_fn *cb_fn,
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void *arg, void *data, int ao2_flags, int rdlock);
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struct ast_channel *(*get_by_name_prefix)(struct ast_channelstorage_instance *driver, const char *name, size_t len, int rdlock);
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struct ast_channel *(*get_by_name_prefix_or_uniqueid)(struct ast_channelstorage_instance *driver, const char *name, size_t len, int rdlock);
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struct ast_channel *(*get_by_exten)(struct ast_channelstorage_instance *driver, const char *exten, const char *context, int rdlock);
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struct ast_channel *(*get_by_uniqueid)(struct ast_channelstorage_instance *driver, const char *uniqueid, int rdlock);
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struct ast_channel_iterator *(*iterator_all_new)(struct ast_channelstorage_instance *driver);
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struct ast_channel_iterator *(*iterator_by_exten_new)
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(struct ast_channelstorage_instance *driver, const char *exten, const char *context);
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struct ast_channel_iterator *(*iterator_by_name_new)
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(struct ast_channelstorage_instance *driver, const char *driver_name, size_t name_len);
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struct ast_channel *(*iterator_next)(struct ast_channelstorage_instance *driver, struct ast_channel_iterator *i);
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struct ast_channel_iterator *(*iterator_destroy)(
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struct ast_channelstorage_instance *driver, struct ast_channel_iterator *i);
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char name[0];
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};
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#define CHANNELSTORAGE_API(_instance, _func, ...) \
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(_instance)->_func((_instance), ##__VA_ARGS__)
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int ast_channelstorage_init(void);
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struct ast_channelstorage_instance *ast_channelstorage_open(
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const struct ast_channelstorage_driver *storage_driver, const char *instance_name);
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void ast_channelstorage_close(struct ast_channelstorage_instance *storage_instance);
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int channelstorage_exten_cb(void *obj, void *arg, void *data, int flags);
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struct ast_channel *channelstorage_by_exten(struct ast_channelstorage_instance *driver,
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const char *exten, const char *context, int rdlock);
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int channelstorage_name_cb(void *obj, void *arg, void *data, int flags);
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struct ast_channel *channelstorage_by_name_or_uniqueid(struct ast_channelstorage_instance *driver,
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const char *name, int rdlock);
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struct ast_channel *channelstorage_by_name_prefix_or_uniqueid(struct ast_channelstorage_instance *driver,
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const char *name, size_t name_len, int rdlock);
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int channelstorage_uniqueid_cb(void *obj, void *arg, void *data, int flags);
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struct ast_channel *channelstorage_by_uniqueid(struct ast_channelstorage_instance *driver,
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const char *uniqueid, int rdlock);
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#if defined(__cplusplus) || defined(c_plusplus)
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}
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#endif
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#endif /* CHANNELSTORAGE_H_ */
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