Extract the locking and logging code

The locking code gets its own module, since it's more fundamental
than the higher-level locking code.

Extracting the logging code was the whole point here. :)

6 files changed, 259 insertions, 0 deletions

diff --git a/src/lib/lock/.may_include b/src/lib/lock/.may_include
new file mode 100644
index 0000000000..9522e3af49
--- /dev/null
+++ b/src/lib/lock/.may_include
@@ -0,0 +1,5 @@
+orconfig.h
+lib/cc/*.h
+lib/err/*.h
+lib/lock/*.h
+lib/malloc/*.h
diff --git a/src/lib/lock/compat_mutex.c b/src/lib/lock/compat_mutex.c
new file mode 100644
index 0000000000..e0f6224a83
--- /dev/null
+++ b/src/lib/lock/compat_mutex.c
@@ -0,0 +1,34 @@
+/* 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 */
+
+#include "lib/lock/compat_mutex.h"
+#include "lib/malloc/util_malloc.h"
+
+/** Return a newly allocated, ready-for-use mutex. */
+tor_mutex_t *
+tor_mutex_new(void)
+{
+  tor_mutex_t *m = tor_malloc_zero(sizeof(tor_mutex_t));
+  tor_mutex_init(m);
+  return m;
+}
+/** Return a newly allocated, ready-for-use mutex.  This one might be
+ * non-recursive, if that's faster. */
+tor_mutex_t *
+tor_mutex_new_nonrecursive(void)
+{
+  tor_mutex_t *m = tor_malloc_zero(sizeof(tor_mutex_t));
+  tor_mutex_init_nonrecursive(m);
+  return m;
+}
+/** Release all storage and system resources held by <b>m</b>. */
+void
+tor_mutex_free_(tor_mutex_t *m)
+{
+  if (!m)
+    return;
+  tor_mutex_uninit(m);
+  tor_free(m);
+}
diff --git a/src/lib/lock/compat_mutex.h b/src/lib/lock/compat_mutex.h
new file mode 100644
index 0000000000..92978086ac
--- /dev/null
+++ b/src/lib/lock/compat_mutex.h
@@ -0,0 +1,60 @@
+/* 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 */
+
+#ifndef TOR_COMPAT_MUTEX_H
+#define TOR_COMPAT_MUTEX_H
+
+#include "orconfig.h"
+#include "lib/cc/torint.h"
+#include "lib/malloc/util_malloc.h"
+
+#if defined(HAVE_PTHREAD_H) && !defined(_WIN32)
+#include <pthread.h>
+#endif
+
+#if defined(_WIN32)
+#include <windows.h>
+#endif
+
+#if defined(_WIN32)
+#define USE_WIN32_THREADS
+#elif defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_CREATE)
+#define USE_PTHREADS
+#else
+#error "No threading system was found"
+#endif /* defined(_WIN32) || ... */
+
+/* Because we use threads instead of processes on most platforms (Windows,
+ * Linux, etc), we need locking for them.  On platforms with poor thread
+ * support or broken gethostbyname_r, these functions are no-ops. */
+
+/** A generic lock structure for multithreaded builds. */
+typedef struct tor_mutex_t {
+#if defined(USE_WIN32_THREADS)
+  /** Windows-only: on windows, we implement locks with CRITICAL_SECTIONS. */
+  CRITICAL_SECTION mutex;
+#elif defined(USE_PTHREADS)
+  /** Pthreads-only: with pthreads, we implement locks with
+   * pthread_mutex_t. */
+  pthread_mutex_t mutex;
+#else
+  /** No-threads only: Dummy variable so that tor_mutex_t takes up space. */
+  int _unused;
+#endif /* defined(USE_WIN32_MUTEX) || ... */
+} tor_mutex_t;
+
+tor_mutex_t *tor_mutex_new(void);
+tor_mutex_t *tor_mutex_new_nonrecursive(void);
+void tor_mutex_init(tor_mutex_t *m);
+void tor_mutex_init_nonrecursive(tor_mutex_t *m);
+void tor_mutex_acquire(tor_mutex_t *m);
+void tor_mutex_release(tor_mutex_t *m);
+void tor_mutex_free_(tor_mutex_t *m);
+#define tor_mutex_free(m) FREE_AND_NULL(tor_mutex_t, tor_mutex_free_, (m))
+void tor_mutex_uninit(tor_mutex_t *m);
+
+void tor_locking_init(void);
+
+#endif /* !defined(TOR_COMPAT_MUTEX_H) */
diff --git a/src/lib/lock/compat_mutex_pthreads.c b/src/lib/lock/compat_mutex_pthreads.c
new file mode 100644
index 0000000000..390da4fb81
--- /dev/null
+++ b/src/lib/lock/compat_mutex_pthreads.c
@@ -0,0 +1,97 @@
+/* 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 */
+
+#include "lib/lock/compat_mutex.h"
+#include "lib/cc/compat_compiler.h"
+#include "lib/err/torerr.h"
+
+/** A mutex attribute that we're going to use to tell pthreads that we want
+ * "recursive" mutexes (i.e., once we can re-lock if we're already holding
+ * them.) */
+static pthread_mutexattr_t attr_recursive;
+static int attr_initialized = 0;
+
+void
+tor_locking_init(void)
+{
+  if (!attr_initialized) {
+    pthread_mutexattr_init(&attr_recursive);
+    pthread_mutexattr_settype(&attr_recursive, PTHREAD_MUTEX_RECURSIVE);
+    attr_initialized = 1;
+  }
+}
+
+/** Initialize <b>mutex</b> so it can be locked.  Every mutex must be set
+ * up with tor_mutex_init() or tor_mutex_new(); not both. */
+void
+tor_mutex_init(tor_mutex_t *mutex)
+{
+  if (PREDICT_UNLIKELY(!attr_initialized))
+    tor_locking_init(); // LCOV_EXCL_LINE
+  const int err = pthread_mutex_init(&mutex->mutex, &attr_recursive);
+  if (PREDICT_UNLIKELY(err)) {
+    // LCOV_EXCL_START
+    raw_assert_unreached_msg("Error creating a mutex.");
+    // LCOV_EXCL_STOP
+  }
+}
+
+/** As tor_mutex_init, but initialize a mutex suitable that may be
+ * non-recursive, if the OS supports that. */
+void
+tor_mutex_init_nonrecursive(tor_mutex_t *mutex)
+{
+  int err;
+  if (!attr_initialized)
+    tor_locking_init(); // LCOV_EXCL_LINE
+  err = pthread_mutex_init(&mutex->mutex, NULL);
+  if (PREDICT_UNLIKELY(err)) {
+    // LCOV_EXCL_START
+    raw_assert_unreached_msg("Error creating a mutex.");
+    // LCOV_EXCL_STOP
+  }
+}
+
+/** Wait until <b>m</b> is free, then acquire it. */
+void
+tor_mutex_acquire(tor_mutex_t *m)
+{
+  int err;
+  raw_assert(m);
+  err = pthread_mutex_lock(&m->mutex);
+  if (PREDICT_UNLIKELY(err)) {
+    // LCOV_EXCL_START
+    raw_assert_unreached_msg("Error locking a mutex.");
+    // LCOV_EXCL_STOP
+  }
+}
+/** Release the lock <b>m</b> so another thread can have it. */
+void
+tor_mutex_release(tor_mutex_t *m)
+{
+  int err;
+  raw_assert(m);
+  err = pthread_mutex_unlock(&m->mutex);
+  if (PREDICT_UNLIKELY(err)) {
+    // LCOV_EXCL_START
+    raw_assert_unreached_msg("Error unlocking a mutex.");
+    // LCOV_EXCL_STOP
+  }
+}
+/** Clean up the mutex <b>m</b> so that it no longer uses any system
+ * resources.  Does not free <b>m</b>.  This function must only be called on
+ * mutexes from tor_mutex_init(). */
+void
+tor_mutex_uninit(tor_mutex_t *m)
+{
+  int err;
+  raw_assert(m);
+  err = pthread_mutex_destroy(&m->mutex);
+  if (PREDICT_UNLIKELY(err)) {
+    // LCOV_EXCL_START
+    raw_assert_unreached_msg("Error destroying a mutex.");
+    // LCOV_EXCL_STOP
+  }
+}
diff --git a/src/lib/lock/compat_mutex_winthreads.c b/src/lib/lock/compat_mutex_winthreads.c
new file mode 100644
index 0000000000..c92eb62913
--- /dev/null
+++ b/src/lib/lock/compat_mutex_winthreads.c
@@ -0,0 +1,39 @@
+/* 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 */
+
+#include "lib/lock/compat_mutex.h"
+
+void
+tor_locking_init(void)
+{
+}
+
+void
+tor_mutex_init(tor_mutex_t *m)
+{
+  InitializeCriticalSection(&m->mutex);
+}
+void
+tor_mutex_init_nonrecursive(tor_mutex_t *m)
+{
+  InitializeCriticalSection(&m->mutex);
+}
+
+void
+tor_mutex_uninit(tor_mutex_t *m)
+{
+  DeleteCriticalSection(&m->mutex);
+}
+void
+tor_mutex_acquire(tor_mutex_t *m)
+{
+  raw_assert(m);
+  EnterCriticalSection(&m->mutex);
+}
+void
+tor_mutex_release(tor_mutex_t *m)
+{
+  LeaveCriticalSection(&m->mutex);
+}
diff --git a/src/lib/lock/include.am b/src/lib/lock/include.am
new file mode 100644
index 0000000000..4e6f444347
--- /dev/null
+++ b/src/lib/lock/include.am
@@ -0,0 +1,24 @@
+
+noinst_LIBRARIES += src/lib/libtor-lock.a
+
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += src/lib/libtor-lock-testing.a
+endif
+
+src_lib_libtor_lock_a_SOURCES =			\
+	src/lib/lock/compat_mutex.c
+
+if THREADS_PTHREADS
+src_lib_libtor_lock_a_SOURCES += src/lib/lock/compat_mutex_pthreads.c
+endif
+if THREADS_WIN32
+src_lib_libtor_lock_a_SOURCES += src/lib/lock/compat_mutex_winthreads.c
+endif
+
+src_lib_libtor_lock_testing_a_SOURCES = \
+	$(src_lib_libtor_lock_a_SOURCES)
+src_lib_libtor_lock_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
+src_lib_libtor_lock_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
+noinst_HEADERS +=					\
+	src/lib/lock/compat_mutex.h