commit 0fade37afd60c3f0e387172e03759e055f831d30
author Roman Stratiienko <r.stratiienko@gmail.com> Sat Feb 20 13:59:55 2021 +0200
committer Roman Stratiienko <r.stratiienko@gmail.com> Sat Jul 24 17:59:09 2021 +0300
tree 247fb23bfac5a18ce8dc8d90efffa3166845b36d
parent 5128715b42e6713b98244bd05f218b8800a39b74

drm_hwcomposer: Rework autofd

Motivation:

Current implementation of UniqueFd can be used in a different ways,
making analytical tracking of FD lifecycle much harder than it may be.
Keep this part clean is very important, since any wrong code may open
a hard-to-detect runtime bugs and fd leaks, which may accidentally slip
into the production.

Implementation:

1. Combine UniqueFd anf OutputFd into single class.
2. Reduce the API to be minimal and sufficient.
3. Document the API and use cases.
4. Move to utils/UniqueFd.h.
5. dup(fd) was replaced with fcntl(fd, F_DUPFD_CLOEXEC)) to
   address clang-tidy findings. Find more information at [1]

[1]: https://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-dup.html

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>

drm/DrmDevice.cpp

diff --git a/drm/DrmDevice.cpp b/drm/DrmDevice.cpp
index d9198d4..abc8edc 100644
--- a/drm/DrmDevice.cpp
+++ b/drm/DrmDevice.cpp
@@ -122,7 +122,7 @@
 
 std::tuple<int, int> DrmDevice::Init(const char *path, int num_displays) {
   /* TODO: Use drmOpenControl here instead */
-  fd_.Set(open(path, O_RDWR | O_CLOEXEC));
+  fd_ = UniqueFd(open(path, O_RDWR | O_CLOEXEC));
   if (fd() < 0) {
     ALOGE("Failed to open dri %s: %s", path, strerror(errno));
     return std::make_tuple(-ENODEV, 0);
@@ -585,9 +585,9 @@
 }
 
 std::string DrmDevice::GetName() const {
-  auto *ver = drmGetVersion(fd_.get());
+  auto *ver = drmGetVersion(fd());
   if (!ver) {
-    ALOGW("Failed to get drm version for fd=%d", fd_.get());
+    ALOGW("Failed to get drm version for fd=%d", fd());
     return "generic";
   }
 

drm/DrmDevice.h

diff --git a/drm/DrmDevice.h b/drm/DrmDevice.h
index c92004b..dfca263 100644
--- a/drm/DrmDevice.h
+++ b/drm/DrmDevice.h
@@ -28,6 +28,7 @@
 #include "DrmEventListener.h"
 #include "DrmFbImporter.h"
 #include "DrmPlane.h"
+#include "utils/UniqueFd.h"
 
 namespace android {
 
@@ -42,7 +43,7 @@
   std::tuple<int, int> Init(const char *path, int num_displays);
 
   int fd() const {
-    return fd_.get();
+    return fd_.Get();
   }
 
   const std::vector<std::unique_ptr<DrmConnector>> &connectors() const {

drm/DrmEventListener.cpp

diff --git a/drm/DrmEventListener.cpp b/drm/DrmEventListener.cpp
index a6eee47..b303653 100644
--- a/drm/DrmEventListener.cpp
+++ b/drm/DrmEventListener.cpp
@@ -39,11 +39,11 @@
 }
 
 int DrmEventListener::Init() {
-  uevent_fd_.Set(
+  uevent_fd_ = UniqueFd(
       socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT));
-  if (uevent_fd_.get() < 0) {
+  if (!uevent_fd_) {
     ALOGE("Failed to open uevent socket: %s", strerror(errno));
-    return uevent_fd_.get();
+    return -errno;
   }
 
   struct sockaddr_nl addr {};
@@ -51,7 +51,7 @@
   addr.nl_pid = 0;
   addr.nl_groups = 0xFFFFFFFF;
 
-  int ret = bind(uevent_fd_.get(), (struct sockaddr *)&addr, sizeof(addr));
+  int ret = bind(uevent_fd_.Get(), (struct sockaddr *)&addr, sizeof(addr));
   if (ret) {
     ALOGE("Failed to bind uevent socket: %s", strerror(errno));
     return -errno;
@@ -60,8 +60,8 @@
   // NOLINTNEXTLINE(readability-isolate-declaration)
   FD_ZERO(&fds_);
   FD_SET(drm_->fd(), &fds_);
-  FD_SET(uevent_fd_.get(), &fds_);
-  max_fd_ = std::max(drm_->fd(), uevent_fd_.get());
+  FD_SET(uevent_fd_.Get(), &fds_);
+  max_fd_ = std::max(drm_->fd(), uevent_fd_.Get());
 
   return InitWorker();
 }
@@ -96,7 +96,7 @@
     ALOGE("Failed to get monotonic clock on hotplug %d", ret);
 
   while (true) {
-    ret = read(uevent_fd_.get(), &buffer, sizeof(buffer));
+    ret = read(uevent_fd_.Get(), &buffer, sizeof(buffer));
     if (ret == 0)
       return;
 
@@ -139,7 +139,7 @@
     drmHandleEvent(drm_->fd(), &event_context);
   }
 
-  if (FD_ISSET(uevent_fd_.get(), &fds_))
+  if (FD_ISSET(uevent_fd_.Get(), &fds_))
     UEventHandler();
 }
 }  // namespace android

drm/DrmEventListener.h

diff --git a/drm/DrmEventListener.h b/drm/DrmEventListener.h
index c880a8c..f1f7310 100644
--- a/drm/DrmEventListener.h
+++ b/drm/DrmEventListener.h
@@ -17,7 +17,7 @@
 #ifndef ANDROID_DRM_EVENT_LISTENER_H_
 #define ANDROID_DRM_EVENT_LISTENER_H_
 
-#include "autofd.h"
+#include "utils/UniqueFd.h"
 #include "utils/Worker.h"
 
 namespace android {