commit 920fddc90af0866883be9a2c6d8e7ef34f30cef9
author Yifan Hong <elsk@google.com> Tue Oct 01 19:26:58 2019 -0700
committer Yifan Hong <elsk@google.com> Tue Oct 01 19:43:33 2019 -0700
tree e0a00402d9215b6b61502d31dc2747e3769b6009
parent 4e63bdd1f84f3dc659d958116df122bd8cd432cb

Fix fds libdm_test

Failed because of double free of fds.
Test: run it

Change-Id: I25d7d590ca52d57fb14a5483ff8751127f6a48a6

fs_mgr/libdm/include/libdm/loop_control.h

diff --git a/fs_mgr/libdm/include/libdm/loop_control.h b/fs_mgr/libdm/include/libdm/loop_control.h
index eeed6b5..ad53c11 100644
--- a/fs_mgr/libdm/include/libdm/loop_control.h
+++ b/fs_mgr/libdm/include/libdm/loop_control.h
@@ -64,7 +64,8 @@
   public:
     // Create a loop device for the given file descriptor. It is closed when
     // LoopDevice is destroyed only if auto_close is true.
-    LoopDevice(int fd, const std::chrono::milliseconds& timeout_ms, bool auto_close = false);
+    LoopDevice(android::base::borrowed_fd fd, const std::chrono::milliseconds& timeout_ms,
+               bool auto_close = false);
     // Create a loop device for the given file path. It will be opened for
     // reading and writing and closed when the loop device is detached.
     LoopDevice(const std::string& path, const std::chrono::milliseconds& timeout_ms);
@@ -81,8 +82,8 @@
   private:
     void Init(const std::chrono::milliseconds& timeout_ms);
 
-    android::base::unique_fd fd_;
-    bool owns_fd_;
+    android::base::borrowed_fd fd_;
+    android::base::unique_fd owned_fd_;
     std::string device_;
     LoopControl control_;
     bool valid_ = false;

fs_mgr/libdm/loop_control.cpp

diff --git a/fs_mgr/libdm/loop_control.cpp b/fs_mgr/libdm/loop_control.cpp
index edc9a45..2e40a18 100644
--- a/fs_mgr/libdm/loop_control.cpp
+++ b/fs_mgr/libdm/loop_control.cpp
@@ -133,18 +133,23 @@
     return true;
 }
 
-LoopDevice::LoopDevice(int fd, const std::chrono::milliseconds& timeout_ms, bool auto_close)
-    : fd_(fd), owns_fd_(auto_close) {
+LoopDevice::LoopDevice(android::base::borrowed_fd fd, const std::chrono::milliseconds& timeout_ms,
+                       bool auto_close)
+    : fd_(fd), owned_fd_(-1) {
+    if (auto_close) {
+        owned_fd_.reset(fd.get());
+    }
     Init(timeout_ms);
 }
 
 LoopDevice::LoopDevice(const std::string& path, const std::chrono::milliseconds& timeout_ms)
-    : fd_(-1), owns_fd_(true) {
-    fd_.reset(open(path.c_str(), O_RDWR | O_CLOEXEC));
-    if (fd_ < -1) {
+    : fd_(-1), owned_fd_(-1) {
+    owned_fd_.reset(open(path.c_str(), O_RDWR | O_CLOEXEC));
+    if (owned_fd_ == -1) {
         PLOG(ERROR) << "open failed for " << path;
         return;
     }
+    fd_ = owned_fd_;
     Init(timeout_ms);
 }
 
@@ -152,13 +157,10 @@
     if (valid()) {
         control_.Detach(device_);
     }
-    if (!owns_fd_) {
-        (void)fd_.release();
-    }
 }
 
 void LoopDevice::Init(const std::chrono::milliseconds& timeout_ms) {
-    valid_ = control_.Attach(fd_, timeout_ms, &device_);
+    valid_ = control_.Attach(fd_.get(), timeout_ms, &device_);
 }
 
 }  // namespace dm