msm8976-common: Build libc_shim from source

Change-Id: I040c3023f81322140d153cb14be9578457777ac2

libc_shim/Android.mk

@@ -0,0 +1,31 @@
+#
+# Copyright (C) 2017 The LineageOS Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+    bionic/bionic_time_conversions.cpp \
+    bionic/pthread_cond.cpp
+
+LOCAL_SHARED_LIBRARIES := libc
+
+LOCAL_MODULE := libc_shim
+LOCAL_MODULE_TAGS := optional
+
+LOCAL_32_BIT_ONLY := true
+
+include $(BUILD_SHARED_LIBRARY)

libc_shim/bionic/bionic_time_conversions.cpp

@@ -0,0 +1,17 @@
+#include "private/bionic_time_conversions.h"
+
+#define NS_PER_S 1000000000
+
+bool timespec_from_absolute_timespec(timespec& ts, const timespec& abs_ts, clockid_t clock) {
+  clock_gettime(clock, &ts);
+  ts.tv_sec = abs_ts.tv_sec - ts.tv_sec;
+  ts.tv_nsec = abs_ts.tv_nsec - ts.tv_nsec;
+  if (ts.tv_nsec < 0) {
+    ts.tv_sec--;
+    ts.tv_nsec += NS_PER_S;
+  }
+  if (ts.tv_nsec < 0 || ts.tv_sec < 0) {
+    return false;
+  }
+  return true;
+}

libc_shim/bionic/pthread_cond.cpp

@@ -0,0 +1,79 @@
+#include <pthread.h>
+
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <linux/futex.h>
+#include <errno.h>
+#include <stdatomic.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "private/bionic_futex.h"
+#include "private/bionic_time_conversions.h"
+
+#define COND_SHARED_MASK 0x0001
+#define COND_CLOCK_MASK 0x0002
+
+#define COND_IS_SHARED(c) (((c) & COND_SHARED_MASK) != 0)
+#define COND_GET_CLOCK(c) (((c) & COND_CLOCK_MASK) >> 1)
+
+struct pthread_cond_internal_t {
+  atomic_uint state;
+
+  bool process_shared() {
+    return COND_IS_SHARED(atomic_load_explicit(&state, memory_order_relaxed));
+  }
+
+  int get_clock() {
+    return COND_GET_CLOCK(atomic_load_explicit(&state, memory_order_relaxed));
+  }
+
+#if defined(__LP64__)
+  char __reserved[44];
+#endif
+};
+
+static pthread_cond_internal_t* __get_internal_cond(pthread_cond_t* cond_interface) {
+  return reinterpret_cast<pthread_cond_internal_t*>(cond_interface);
+}
+
+static int __pthread_cond_timedwait_relative(pthread_cond_internal_t* cond, pthread_mutex_t* mutex,
+                                             const timespec* rel_timeout_or_null) {
+  unsigned int old_state = atomic_load_explicit(&cond->state, memory_order_relaxed);
+
+  pthread_mutex_unlock(mutex);
+  int status = __futex_wait_ex(&cond->state, cond->process_shared(), old_state, rel_timeout_or_null);
+  pthread_mutex_lock(mutex);
+
+  if (status == -ETIMEDOUT) {
+    return ETIMEDOUT;
+  }
+  return 0;
+}
+
+static int __pthread_cond_timedwait(pthread_cond_internal_t* cond, pthread_mutex_t* mutex,
+                                    const timespec* abs_timeout_or_null, clockid_t clock) {
+  timespec ts;
+  timespec* rel_timeout = NULL;
+
+  if (abs_timeout_or_null != NULL) {
+    rel_timeout = &ts;
+    if (!timespec_from_absolute_timespec(*rel_timeout, *abs_timeout_or_null, clock)) {
+      return ETIMEDOUT;
+    }
+  }
+
+  return __pthread_cond_timedwait_relative(cond, mutex, rel_timeout);
+}
+
+int pthread_cond_timedwait(pthread_cond_t *cond_interface, pthread_mutex_t * mutex,
+                           const timespec *abstime) {
+
+  pthread_cond_internal_t* cond = __get_internal_cond(cond_interface);
+  return __pthread_cond_timedwait(cond, mutex, abstime, cond->get_clock());
+}
+
+int pthread_cond_wait(pthread_cond_t* cond_interface, pthread_mutex_t* mutex) {
+  pthread_cond_internal_t* cond = __get_internal_cond(cond_interface);
+  return __pthread_cond_timedwait(cond, mutex, NULL, cond->get_clock());
+}

libc_shim/private/bionic_futex.h

@@ -0,0 +1,14 @@
+static inline __always_inline int __futex(volatile void* ftx, int op, int value, const struct timespec* timeout) {
+  // Our generated syscall assembler sets errno, but our callers (pthread functions) don't want to.
+  int saved_errno = errno;
+  int result = syscall(__NR_futex, ftx, op, value, timeout);
+  if (__predict_false(result == -1)) {
+    result = -errno;
+    errno = saved_errno;
+  }
+  return result;
+}
+
+static inline int __futex_wait_ex(volatile void* ftx, bool shared, int value, const struct timespec* timeout) {
+  return __futex(ftx, shared ? FUTEX_WAIT : FUTEX_WAIT_PRIVATE, value, timeout);
+}

libc_shim/private/bionic_time_conversions.h

@@ -0,0 +1,3 @@
+#include <time.h>
+
+bool timespec_from_absolute_timespec(timespec& ts, const timespec& abs_ts, clockid_t clock);

msm8976.mk

@@ -105,8 +105,8 @@ PRODUCT_PACKAGES += \
     Gello
 
 # Camera
-PRODUCT_COPY_FILES += \
-    $(LOCAL_PATH)/prebuilt/libc_shim.so:system/lib/libc_shim.so
+PRODUCT_PACKAGES += \
+    libc_shim
 
 # Display
 PRODUCT_PACKAGES += \