sigchain: use libasync_safe logging.

__android_log_write doesn't have async safe guarantees. Use
libasync_safe, which has the added benefit of setting the abort message
for fatal errors.

Bug: http://b/67632085
Test: treehugger
Change-Id: I4d710753fddbce43fca44485443c446ed745ec30

4 files changed, 49 insertions, 44 deletions

diff --git a/sigchainlib/Android.bp b/sigchainlib/Android.bp
index 1f490cd3b9..a151d7a6bc 100644
--- a/sigchainlib/Android.bp
+++ b/sigchainlib/Android.bp
@@ -35,7 +35,7 @@ cc_library {
         },
 
         android: {
-            shared_libs: ["liblog"],
+            whole_static_libs: ["libasync_safe"],
         },
     },
     // Sigchainlib is whole-statically linked into binaries. For Android.mk-based binaries,
@@ -56,7 +56,7 @@ cc_library_static {
     srcs: ["sigchain_dummy.cc"],
     target: {
         android: {
-            shared_libs: ["liblog"],
+            whole_static_libs: ["libasync_safe"],
         },
     },
 }
diff --git a/sigchainlib/log.h b/sigchainlib/log.h
new file mode 100644
index 0000000000..d689930c1e
--- /dev/null
+++ b/sigchainlib/log.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2018 The Android Open Source 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.
+ */
+
+#ifndef ART_SIGCHAINLIB_LOG_H_
+#define ART_SIGCHAINLIB_LOG_H_
+
+#if defined(__ANDROID__)
+
+#include <async_safe/log.h>
+
+#define log(...) async_safe_format_log(ANDROID_LOG_ERROR, "libsigchain", __VA_ARGS__)
+#define fatal async_safe_fatal
+
+#else
+
+#include <stdarg.h>
+#include <stdio.h>
+
+static void log(const char* format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  vprintf(format, ap);
+  va_end(ap);
+
+  printf("\n");
+}
+
+#define fatal(...) log(__VA_ARGS__); abort()
+
+#endif
+
+#endif  // ART_SIGCHAINLIB_LOG_H_
diff --git a/sigchainlib/sigchain.cc b/sigchainlib/sigchain.cc
index 3127c5cfbd..2e5f46ca69 100644
--- a/sigchainlib/sigchain.cc
+++ b/sigchainlib/sigchain.cc
@@ -14,13 +14,6 @@
  * limitations under the License.
  */
 
-#ifdef ART_TARGET_ANDROID
-#include <android/log.h>
-#else
-#include <stdarg.h>
-#include <iostream>
-#endif
-
 #include <dlfcn.h>
 #include <errno.h>
 #include <pthread.h>
@@ -35,6 +28,7 @@
 #include <type_traits>
 #include <utility>
 
+#include "log.h"
 #include "sigchain.h"
 
 #if defined(__APPLE__)
@@ -65,21 +59,6 @@
 //               doesn't have SA_RESTART, and raise the signal to avoid restarting syscalls that are
 //               expected to be interrupted?
 
-static void log(const char* format, ...) {
-  char buf[256];
-  va_list ap;
-  va_start(ap, format);
-  vsnprintf(buf, sizeof(buf), format, ap);
-#ifdef ART_TARGET_ANDROID
-  __android_log_write(ANDROID_LOG_ERROR, "libsigchain", buf);
-#else
-  std::cout << buf << "\n";
-#endif
-  va_end(ap);
-}
-
-#define fatal(...) log(__VA_ARGS__); abort()
-
 #if defined(__BIONIC__) && !defined(__LP64__) && !defined(__mips__)
 static int sigismember(const sigset64_t* sigset, int signum) {
   return sigismember64(sigset, signum);
diff --git a/sigchainlib/sigchain_dummy.cc b/sigchainlib/sigchain_dummy.cc
index edce965e33..c274530987 100644
--- a/sigchainlib/sigchain_dummy.cc
+++ b/sigchainlib/sigchain_dummy.cc
@@ -17,13 +17,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#ifdef ART_TARGET_ANDROID
-#include <android/log.h>
-#else
-#include <stdarg.h>
-#include <iostream>
-#endif
-
+#include "log.h"
 #include "sigchain.h"
 
 #define ATTRIBUTE_UNUSED __attribute__((__unused__))
@@ -33,19 +27,6 @@
 #pragma GCC diagnostic ignored "-Wunknown-pragmas"
 #pragma GCC diagnostic ignored "-Wmissing-noreturn"
 
-static void log(const char* format, ...) {
-  char buf[256];
-  va_list ap;
-  va_start(ap, format);
-  vsnprintf(buf, sizeof(buf), format, ap);
-#ifdef ART_TARGET_ANDROID
-  __android_log_write(ANDROID_LOG_ERROR, "libsigchain", buf);
-#else
-  std::cout << buf << "\n";
-#endif
-  va_end(ap);
-}
-
 namespace art {
 
 extern "C" void EnsureFrontOfChain(int signal ATTRIBUTE_UNUSED) {