[compiler-rt] a1f6ff2 - [scudo][standalone] Fix Android logging

[Kostya Kortchinsky via llvm-commits]

Author: Kostya Kortchinsky
Date: 2020-01-28T11:03:39-08:00
New Revision: a1f6ff26814b86fdd7dfc9083bbefe5cf1790ab8

URL: https://github.com/llvm/llvm-project/commit/a1f6ff26814b86fdd7dfc9083bbefe5cf1790ab8
DIFF: https://github.com/llvm/llvm-project/commit/a1f6ff26814b86fdd7dfc9083bbefe5cf1790ab8.diff

LOG: [scudo][standalone] Fix Android logging

Summary:
Zygote & children's stderr is lost, so use Bionic's provided allocation
free syslog function for `outputRaw`. Get rid of the mutex as it's not
vital and could cause issues with `fork`.

Reviewers: cferris, pcc, eugenis, hctim, morehouse

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D73561

Added: 
    

Modified: 
    compiler-rt/lib/scudo/standalone/linux.cpp

Removed: 
    


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diff  --git a/compiler-rt/lib/scudo/standalone/linux.cpp b/compiler-rt/lib/scudo/standalone/linux.cpp
index 3b7562844d72..040e1f039efa 100644
--- a/compiler-rt/lib/scudo/standalone/linux.cpp
+++ b/compiler-rt/lib/scudo/standalone/linux.cpp
@@ -164,10 +164,17 @@ bool getRandom(void *Buffer, uptr Length, UNUSED bool Blocking) {
   return (ReadBytes == static_cast<ssize_t>(Length));
 }
 
+// Allocation free syslog-like API.
+extern "C" WEAK int async_safe_write_log(int pri, const char *tag,
+                                         const char *msg);
+
 void outputRaw(const char *Buffer) {
-  static HybridMutex Mutex;
-  ScopedLock L(Mutex);
-  write(2, Buffer, strlen(Buffer));
+  if (&async_safe_write_log) {
+    constexpr s32 AndroidLogInfo = 4;
+    async_safe_write_log(AndroidLogInfo, "scudo", Buffer);
+  } else {
+    write(2, Buffer, strlen(Buffer));
+  }
 }
 
 extern "C" WEAK void android_set_abort_message(const char *);