diff options
Diffstat (limited to 'src/lib/thread/compat_winthreads.c')
| -rw-r--r-- | src/lib/thread/compat_winthreads.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/src/lib/thread/compat_winthreads.c b/src/lib/thread/compat_winthreads.c new file mode 100644 index 0000000000..7f9877d21e --- /dev/null +++ b/src/lib/thread/compat_winthreads.c @@ -0,0 +1,223 @@ +/* Copyright (c) 2003-2004, Roger Dingledine + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2018, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file compat_winthreads.c + * + * \brief Implementation for the windows-based multithreading backend + * functions. + */ + +#ifdef _WIN32 + +#include <windows.h> +#include <process.h> +#include "lib/thread/threads.h" +#include "lib/log/torlog.h" +#include "lib/log/util_bug.h" +#include "lib/log/win32err.h" + +/* This value is more or less total cargo-cult */ +#define SPIN_COUNT 2000 + +/** Minimalist interface to run a void function in the background. On + * Unix calls fork, on win32 calls beginthread. Returns -1 on failure. + * func should not return, but rather should call spawn_exit. + * + * NOTE: if <b>data</b> is used, it should not be allocated on the stack, + * since in a multithreaded environment, there is no way to be sure that + * the caller's stack will still be around when the called function is + * running. + */ +int +spawn_func(void (*func)(void *), void *data) +{ + int rv; + rv = (int)_beginthread(func, 0, data); + if (rv == (int)-1) + return -1; + return 0; +} + +/** End the current thread/process. + */ +void +spawn_exit(void) +{ + _endthread(); + // LCOV_EXCL_START + //we should never get here. my compiler thinks that _endthread returns, this + //is an attempt to fool it. + tor_assert(0); + _exit(0); // exit ok: unreachable. + // LCOV_EXCL_STOP +} + +unsigned long +tor_get_thread_id(void) +{ + return (unsigned long)GetCurrentThreadId(); +} + +int +tor_cond_init(tor_cond_t *cond) +{ + memset(cond, 0, sizeof(tor_cond_t)); + if (InitializeCriticalSectionAndSpinCount(&cond->lock, SPIN_COUNT)==0) { + return -1; + } + if ((cond->event = CreateEvent(NULL,TRUE,FALSE,NULL)) == NULL) { + DeleteCriticalSection(&cond->lock); + return -1; + } + cond->n_waiting = cond->n_to_wake = cond->generation = 0; + return 0; +} +void +tor_cond_uninit(tor_cond_t *cond) +{ + DeleteCriticalSection(&cond->lock); + CloseHandle(cond->event); +} + +static void +tor_cond_signal_impl(tor_cond_t *cond, int broadcast) +{ + EnterCriticalSection(&cond->lock); + if (broadcast) + cond->n_to_wake = cond->n_waiting; + else + ++cond->n_to_wake; + cond->generation++; + SetEvent(cond->event); + LeaveCriticalSection(&cond->lock); +} +void +tor_cond_signal_one(tor_cond_t *cond) +{ + tor_cond_signal_impl(cond, 0); +} +void +tor_cond_signal_all(tor_cond_t *cond) +{ + tor_cond_signal_impl(cond, 1); +} + +int +tor_threadlocal_init(tor_threadlocal_t *threadlocal) +{ + threadlocal->index = TlsAlloc(); + return (threadlocal->index == TLS_OUT_OF_INDEXES) ? -1 : 0; +} + +void +tor_threadlocal_destroy(tor_threadlocal_t *threadlocal) +{ + TlsFree(threadlocal->index); + memset(threadlocal, 0, sizeof(tor_threadlocal_t)); +} + +void * +tor_threadlocal_get(tor_threadlocal_t *threadlocal) +{ + void *value = TlsGetValue(threadlocal->index); + if (value == NULL) { + DWORD err = GetLastError(); + if (err != ERROR_SUCCESS) { + char *msg = format_win32_error(err); + log_err(LD_GENERAL, "Error retrieving thread-local value: %s", msg); + tor_free(msg); + tor_assert(err == ERROR_SUCCESS); + } + } + return value; +} + +void +tor_threadlocal_set(tor_threadlocal_t *threadlocal, void *value) +{ + BOOL ok = TlsSetValue(threadlocal->index, value); + if (!ok) { + DWORD err = GetLastError(); + char *msg = format_win32_error(err); + log_err(LD_GENERAL, "Error adjusting thread-local value: %s", msg); + tor_free(msg); + tor_assert(ok); + } +} + +int +tor_cond_wait(tor_cond_t *cond, tor_mutex_t *lock_, const struct timeval *tv) +{ + CRITICAL_SECTION *lock = &lock_->mutex; + int generation_at_start; + int waiting = 1; + int result = -1; + DWORD ms = INFINITE, ms_orig = INFINITE, startTime, endTime; + if (tv) + ms_orig = ms = tv->tv_sec*1000 + (tv->tv_usec+999)/1000; + + EnterCriticalSection(&cond->lock); + ++cond->n_waiting; + generation_at_start = cond->generation; + LeaveCriticalSection(&cond->lock); + + LeaveCriticalSection(lock); + + startTime = GetTickCount(); + do { + DWORD res; + res = WaitForSingleObject(cond->event, ms); + EnterCriticalSection(&cond->lock); + if (cond->n_to_wake && + cond->generation != generation_at_start) { + --cond->n_to_wake; + --cond->n_waiting; + result = 0; + waiting = 0; + goto out; + } else if (res != WAIT_OBJECT_0) { + result = (res==WAIT_TIMEOUT) ? 1 : -1; + --cond->n_waiting; + waiting = 0; + goto out; + } else if (ms != INFINITE) { + endTime = GetTickCount(); + if (startTime + ms_orig <= endTime) { + result = 1; /* Timeout */ + --cond->n_waiting; + waiting = 0; + goto out; + } else { + ms = startTime + ms_orig - endTime; + } + } + /* If we make it here, we are still waiting. */ + if (cond->n_to_wake == 0) { + /* There is nobody else who should wake up; reset + * the event. */ + ResetEvent(cond->event); + } + out: + LeaveCriticalSection(&cond->lock); + } while (waiting); + + EnterCriticalSection(lock); + + EnterCriticalSection(&cond->lock); + if (!cond->n_waiting) + ResetEvent(cond->event); + LeaveCriticalSection(&cond->lock); + + return result; +} + +void +tor_threads_init(void) +{ + set_main_thread(); +} + +#endif /* defined(_WIN32) */ |