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/*
* Copyright (C) 2009 Tobias Brunner
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup thread thread
* @{ @ingroup threading
*/
#ifndef THREADING_THREAD_H_
#define THREADING_THREAD_H_
typedef struct thread_t thread_t;
#ifdef __APPLE__
/* thread_create is a syscall used to create Mach kernel threads and although
* there are no errors or warnings during compilation or linkage the dynamic
* linker does not use our implementation, therefore we rename it here
*/
#define thread_create(main, arg) strongswan_thread_create(main, arg)
/* on Mac OS X 10.5 several system calls we use are no cancellation points.
* fortunately, select isn't one of them, so we wrap some of the others with
* calls to select(2).
*/
#include <sys/socket.h>
#include <sys/select.h>
#define WRAP_WITH_SELECT(func, socket, ...)\
fd_set rfds; FD_ZERO(&rfds); FD_SET(socket, &rfds);\
if (select(socket + 1, &rfds, NULL, NULL, NULL) <= 0) { return -1; }\
return func(socket, __VA_ARGS__)
static inline int cancellable_accept(int socket, struct sockaddr *address,
socklen_t *address_len)
{
WRAP_WITH_SELECT(accept, socket, address, address_len);
}
#define accept cancellable_accept
static inline int cancellable_recvfrom(int socket, void *buffer, size_t length,
int flags, struct sockaddr *address, socklen_t *address_len)
{
WRAP_WITH_SELECT(recvfrom, socket, buffer, length, flags, address, address_len);
}
#define recvfrom cancellable_recvfrom
#endif /* __APPLE__ */
/**
* Main function of a thread.
*
* @param arg argument provided to constructor
* @return value provided to threads joining the terminating thread
*/
typedef void *(*thread_main_t)(void *arg);
/**
* Cleanup callback function for a thread.
*
* @param arg argument provided to thread_cleanup_push
*/
typedef void (*thread_cleanup_t)(void *arg);
/**
* Thread wrapper implements simple, portable and advanced thread functions.
*
* @note All threads other than the main thread need either to be joined or
* detached by calling the corresponding method.
*/
struct thread_t {
/**
* Cancel this thread.
*/
void (*cancel)(thread_t *this);
/**
* Send a signal to this thread.
*
* @param sig the signal to be sent to this thread
*/
void (*kill)(thread_t *this, int sig);
/**
* Detach this thread, this automatically destroys the thread object after
* the thread returned from its main function.
*
* @note Calling detach is like calling destroy on other objects.
*/
void (*detach)(thread_t *this);
/**
* Join this thread, this automatically destroys the thread object
* afterwards.
*
* @note Calling join is like calling destroy on other objects.
*
* @return the value returned from the thread's main function or
* a call to exit.
*/
void *(*join)(thread_t *this);
};
/**
* Create a new thread instance.
*
* @param main thread main function
* @param arg argument provided to the main function
* @return thread instance
*/
thread_t *thread_create(thread_main_t main, void *arg);
/**
* Get a thread object for the current thread.
*
* @return thread instance
*/
thread_t *thread_current();
/**
* Get the human-readable ID of the current thread.
*
* The IDs are assigned incrementally starting from 1.
*
* @return human-readable ID
*/
u_int thread_current_id();
/**
* Push a function onto the current thread's cleanup handler stack.
* The callback function is called whenever the thread is cancelled, exits or
* thread_cleanup_pop is called with TRUE as execute argument.
*
* @param cleanup function called on thread exit
* @param arg argument provided to the callback
*/
void thread_cleanup_push(thread_cleanup_t cleanup, void *arg);
/**
* Remove the top function from the current thread's cleanup handler stack
* and optionally execute it.
*
* @param execute TRUE to execute the function
*/
void thread_cleanup_pop(bool execute);
/**
* Enable or disable the cancelability of the current thread. The current
* value is returned.
*
* @param enable TRUE to enable cancelability
* @return the current state of the cancelability
*/
bool thread_cancelability(bool enable);
/**
* Force creation of a cancellation point in the calling thread.
*
* This temporarily enables thread cancelability, tests for a pending
* cancellation request and then disables cancelability again if it was
* disabled before the call to thread_cancellation_point().
*/
void thread_cancellation_point();
/**
* Exit the current thread.
*
* @param val value provided to threads joining the current thread
*/
void thread_exit(void *val);
/**
* Called by the main thread to initialize the thread management.
*/
void threads_init();
/**
* Called by the main thread to deinitialize the thread management.
*/
void threads_deinit();
#ifdef __APPLE__
/*
* While select() is a cancellation point, it seems that OS X does not honor
* pending cancellation points when entering the function. We manually test for
* and honor pending cancellation requests, but this obviously can't prevent
* some race conditions where the the cancellation happens after the check,
* but before the select.
*/
static inline int precancellable_select(int nfds, fd_set *restrict readfds,
fd_set *restrict writefds, fd_set *restrict errorfds,
struct timeval *restrict timeout)
{
if (thread_cancelability(TRUE))
{
thread_cancellation_point();
}
else
{
thread_cancelability(FALSE);
}
return select(nfds, readfds, writefds, errorfds, timeout);
}
#define select precancellable_select
#endif /* __APPLE__ */
#endif /** THREADING_THREAD_H_ @} */
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