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Diffstat (limited to 'main-loop.h')
| -rw-r--r-- | main-loop.h | 306 |
1 files changed, 0 insertions, 306 deletions
diff --git a/main-loop.h b/main-loop.h deleted file mode 100644 index e8059c3d0a..0000000000 --- a/main-loop.h +++ /dev/null @@ -1,306 +0,0 @@ -/* - * QEMU System Emulator - * - * Copyright (c) 2003-2008 Fabrice Bellard - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN - * THE SOFTWARE. - */ - -#ifndef QEMU_MAIN_LOOP_H -#define QEMU_MAIN_LOOP_H 1 - -#include "block/aio.h" - -#define SIG_IPI SIGUSR1 - -/** - * qemu_init_main_loop: Set up the process so that it can run the main loop. - * - * This includes setting up signal handlers. It should be called before - * any other threads are created. In addition, threads other than the - * main one should block signals that are trapped by the main loop. - * For simplicity, you can consider these signals to be safe: SIGUSR1, - * SIGUSR2, thread signals (SIGFPE, SIGILL, SIGSEGV, SIGBUS) and real-time - * signals if available. Remember that Windows in practice does not have - * signals, though. - * - * In the case of QEMU tools, this will also start/initialize timers. - */ -int qemu_init_main_loop(void); - -/** - * main_loop_wait: Run one iteration of the main loop. - * - * If @nonblocking is true, poll for events, otherwise suspend until - * one actually occurs. The main loop usually consists of a loop that - * repeatedly calls main_loop_wait(false). - * - * Main loop services include file descriptor callbacks, bottom halves - * and timers (defined in qemu-timer.h). Bottom halves are similar to timers - * that execute immediately, but have a lower overhead and scheduling them - * is wait-free, thread-safe and signal-safe. - * - * It is sometimes useful to put a whole program in a coroutine. In this - * case, the coroutine actually should be started from within the main loop, - * so that the main loop can run whenever the coroutine yields. To do this, - * you can use a bottom half to enter the coroutine as soon as the main loop - * starts: - * - * void enter_co_bh(void *opaque) { - * QEMUCoroutine *co = opaque; - * qemu_coroutine_enter(co, NULL); - * } - * - * ... - * QEMUCoroutine *co = qemu_coroutine_create(coroutine_entry); - * QEMUBH *start_bh = qemu_bh_new(enter_co_bh, co); - * qemu_bh_schedule(start_bh); - * while (...) { - * main_loop_wait(false); - * } - * - * (In the future we may provide a wrapper for this). - * - * @nonblocking: Whether the caller should block until an event occurs. - */ -int main_loop_wait(int nonblocking); - -/** - * qemu_notify_event: Force processing of pending events. - * - * Similar to signaling a condition variable, qemu_notify_event forces - * main_loop_wait to look at pending events and exit. The caller of - * main_loop_wait will usually call it again very soon, so qemu_notify_event - * also has the side effect of recalculating the sets of file descriptors - * that the main loop waits for. - * - * Calling qemu_notify_event is rarely necessary, because main loop - * services (bottom halves and timers) call it themselves. One notable - * exception occurs when using qemu_set_fd_handler2 (see below). - */ -void qemu_notify_event(void); - -#ifdef _WIN32 -/* return TRUE if no sleep should be done afterwards */ -typedef int PollingFunc(void *opaque); - -/** - * qemu_add_polling_cb: Register a Windows-specific polling callback - * - * Currently, under Windows some events are polled rather than waited for. - * Polling callbacks do not ensure that @func is called timely, because - * the main loop might wait for an arbitrarily long time. If possible, - * you should instead create a separate thread that does a blocking poll - * and set a Win32 event object. The event can then be passed to - * qemu_add_wait_object. - * - * Polling callbacks really have nothing Windows specific in them, but - * as they are a hack and are currently not necessary under POSIX systems, - * they are only available when QEMU is running under Windows. - * - * @func: The function that does the polling, and returns 1 to force - * immediate completion of main_loop_wait. - * @opaque: A pointer-size value that is passed to @func. - */ -int qemu_add_polling_cb(PollingFunc *func, void *opaque); - -/** - * qemu_del_polling_cb: Unregister a Windows-specific polling callback - * - * This function removes a callback that was registered with - * qemu_add_polling_cb. - * - * @func: The function that was passed to qemu_add_polling_cb. - * @opaque: A pointer-size value that was passed to qemu_add_polling_cb. - */ -void qemu_del_polling_cb(PollingFunc *func, void *opaque); - -/* Wait objects handling */ -typedef void WaitObjectFunc(void *opaque); - -/** - * qemu_add_wait_object: Register a callback for a Windows handle - * - * Under Windows, the iohandler mechanism can only be used with sockets. - * QEMU must use the WaitForMultipleObjects API to wait on other handles. - * This function registers a #HANDLE with QEMU, so that it will be included - * in the main loop's calls to WaitForMultipleObjects. When the handle - * is in a signaled state, QEMU will call @func. - * - * @handle: The Windows handle to be observed. - * @func: A function to be called when @handle is in a signaled state. - * @opaque: A pointer-size value that is passed to @func. - */ -int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); - -/** - * qemu_del_wait_object: Unregister a callback for a Windows handle - * - * This function removes a callback that was registered with - * qemu_add_wait_object. - * - * @func: The function that was passed to qemu_add_wait_object. - * @opaque: A pointer-size value that was passed to qemu_add_wait_object. - */ -void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); -#endif - -/* async I/O support */ - -typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size); -typedef int IOCanReadHandler(void *opaque); - -/** - * qemu_set_fd_handler2: Register a file descriptor with the main loop - * - * This function tells the main loop to wake up whenever one of the - * following conditions is true: - * - * 1) if @fd_write is not %NULL, when the file descriptor is writable; - * - * 2) if @fd_read is not %NULL, when the file descriptor is readable. - * - * @fd_read_poll can be used to disable the @fd_read callback temporarily. - * This is useful to avoid calling qemu_set_fd_handler2 every time the - * client becomes interested in reading (or dually, stops being interested). - * A typical example is when @fd is a listening socket and you want to bound - * the number of active clients. Remember to call qemu_notify_event whenever - * the condition may change from %false to %true. - * - * The callbacks that are set up by qemu_set_fd_handler2 are level-triggered. - * If @fd_read does not read from @fd, or @fd_write does not write to @fd - * until its buffers are full, they will be called again on the next - * iteration. - * - * @fd: The file descriptor to be observed. Under Windows it must be - * a #SOCKET. - * - * @fd_read_poll: A function that returns 1 if the @fd_read callback - * should be fired. If the function returns 0, the main loop will not - * end its iteration even if @fd becomes readable. - * - * @fd_read: A level-triggered callback that is fired if @fd is readable - * at the beginning of a main loop iteration, or if it becomes readable - * during one. - * - * @fd_write: A level-triggered callback that is fired when @fd is writable - * at the beginning of a main loop iteration, or if it becomes writable - * during one. - * - * @opaque: A pointer-sized value that is passed to @fd_read_poll, - * @fd_read and @fd_write. - */ -int qemu_set_fd_handler2(int fd, - IOCanReadHandler *fd_read_poll, - IOHandler *fd_read, - IOHandler *fd_write, - void *opaque); - -/** - * qemu_set_fd_handler: Register a file descriptor with the main loop - * - * This function tells the main loop to wake up whenever one of the - * following conditions is true: - * - * 1) if @fd_write is not %NULL, when the file descriptor is writable; - * - * 2) if @fd_read is not %NULL, when the file descriptor is readable. - * - * The callbacks that are set up by qemu_set_fd_handler are level-triggered. - * If @fd_read does not read from @fd, or @fd_write does not write to @fd - * until its buffers are full, they will be called again on the next - * iteration. - * - * @fd: The file descriptor to be observed. Under Windows it must be - * a #SOCKET. - * - * @fd_read: A level-triggered callback that is fired if @fd is readable - * at the beginning of a main loop iteration, or if it becomes readable - * during one. - * - * @fd_write: A level-triggered callback that is fired when @fd is writable - * at the beginning of a main loop iteration, or if it becomes writable - * during one. - * - * @opaque: A pointer-sized value that is passed to @fd_read and @fd_write. - */ -int qemu_set_fd_handler(int fd, - IOHandler *fd_read, - IOHandler *fd_write, - void *opaque); - -#ifdef CONFIG_POSIX -/** - * qemu_add_child_watch: Register a child process for reaping. - * - * Under POSIX systems, a parent process must read the exit status of - * its child processes using waitpid, or the operating system will not - * free some of the resources attached to that process. - * - * This function directs the QEMU main loop to observe a child process - * and call waitpid as soon as it exits; the watch is then removed - * automatically. It is useful whenever QEMU forks a child process - * but will find out about its termination by other means such as a - * "broken pipe". - * - * @pid: The pid that QEMU should observe. - */ -int qemu_add_child_watch(pid_t pid); -#endif - -/** - * qemu_mutex_lock_iothread: Lock the main loop mutex. - * - * This function locks the main loop mutex. The mutex is taken by - * qemu_init_main_loop and always taken except while waiting on - * external events (such as with select). The mutex should be taken - * by threads other than the main loop thread when calling - * qemu_bh_new(), qemu_set_fd_handler() and basically all other - * functions documented in this file. - * - * NOTE: tools currently are single-threaded and qemu_mutex_lock_iothread - * is a no-op there. - */ -void qemu_mutex_lock_iothread(void); - -/** - * qemu_mutex_unlock_iothread: Unlock the main loop mutex. - * - * This function unlocks the main loop mutex. The mutex is taken by - * qemu_init_main_loop and always taken except while waiting on - * external events (such as with select). The mutex should be unlocked - * as soon as possible by threads other than the main loop thread, - * because it prevents the main loop from processing callbacks, - * including timers and bottom halves. - * - * NOTE: tools currently are single-threaded and qemu_mutex_unlock_iothread - * is a no-op there. - */ -void qemu_mutex_unlock_iothread(void); - -/* internal interfaces */ - -void qemu_fd_register(int fd); -void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds); -void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int rc); - -QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque); -void qemu_bh_schedule_idle(QEMUBH *bh); - -#endif |