commit 4ff5bae056a55a2fe6f778f31743871f65c8b8e6
author Josh Gao <jmgao@google.com> Thu Jun 01 12:19:53 2017 -0700
committer Josh Gao <jmgao@google.com> Thu Jun 01 12:42:44 2017 -0700
tree 9453ac0ed689d7084b73ede163d29dd3a5d274d0
parent 7ec1b9e56b7edf4c145eb60cc48086652ffb6efd

debuggerd_client: increase pipe buffer size to max.

If a process tries to dump itself (e.g. system_server during ANRs),
crash_dump will block trying to write to its pipe if it's not
sufficiently large. Increase the pipe size to the max, and add a test
to make sure that it's always at least 1MB (the default value).

Bug: http://b/38427757
Test: debuggerd_test
Change-Id: Iddb0cb1e5ce9e687efa9e94c2748a1edfe09f119

debuggerd/client/debuggerd_client.cpp

diff --git a/debuggerd/client/debuggerd_client.cpp b/debuggerd/client/debuggerd_client.cpp
index c357fd6..cb7cbbe 100644
--- a/debuggerd/client/debuggerd_client.cpp
+++ b/debuggerd/client/debuggerd_client.cpp
@@ -28,7 +28,9 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/parseint.h>
 #include <android-base/stringprintf.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <cutils/sockets.h>
 
@@ -117,6 +119,20 @@
     return false;
   }
 
+  std::string pipe_size_str;
+  int pipe_buffer_size = 1024 * 1024;
+  if (android::base::ReadFileToString("/proc/sys/fs/pipe-max-size", &pipe_size_str)) {
+    pipe_size_str = android::base::Trim(pipe_size_str);
+
+    if (!android::base::ParseInt(pipe_size_str.c_str(), &pipe_buffer_size, 0)) {
+      LOG(FATAL) << "failed to parse pipe max size '" << pipe_size_str << "'";
+    }
+  }
+
+  if (fcntl(pipe_read.get(), F_SETPIPE_SZ, pipe_buffer_size) != pipe_buffer_size) {
+    PLOG(ERROR) << "failed to set pipe buffer size";
+  }
+
   if (send_fd(set_timeout(sockfd), &req, sizeof(req), std::move(pipe_write)) != sizeof(req)) {
     PLOG(ERROR) << "libdebuggerd_client: failed to send output fd to tombstoned";
     return false;

debuggerd/debuggerd_test.cpp

diff --git a/debuggerd/debuggerd_test.cpp b/debuggerd/debuggerd_test.cpp
index 8c00b76..9008b95 100644
--- a/debuggerd/debuggerd_test.cpp
+++ b/debuggerd/debuggerd_test.cpp
@@ -119,6 +119,8 @@
     FAIL() << "failed to set pipe size: " << strerror(errno);
   }
 
+  ASSERT_GE(pipe_buffer_size, 1024 * 1024);
+
   if (send_fd(intercept_fd->get(), &req, sizeof(req), std::move(output_pipe_write)) != sizeof(req)) {
     FAIL() << "failed to send output fd to tombstoned: " << strerror(errno);
   }