libbinder: build ParcelFileDescriptor on Trusty

Adds ParcelFileDescriptor.cpp to the Trusty build
which in turn compiles some extra related code from
Parcel.cpp. This code uses fcntl(...O_DUPFD_CLOEXEC...)
to duplicate file descriptors which is not available
on Trusty (or other OSes), so we abstract the relevant
calls to that function in a wrapper in OS.cpp.

Bug: 224644083
Test: m
Test: build on Trusty
Change-Id: I2e0ee517e7c7b55458a6ee6db977985aab4d7c58

1 files changed, 19 insertions, 8 deletions

diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 8b5d11800f..888757214d 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -48,6 +48,7 @@
 #include <utils/String8.h>
 #include <utils/misc.h>
 
+#include "OS.h"
 #include "RpcState.h"
 #include "Static.h"
 #include "Utils.h"
@@ -1477,9 +1478,9 @@ status_t Parcel::writeFileDescriptor(int fd, bool takeOwnership) {
 
 status_t Parcel::writeDupFileDescriptor(int fd)
 {
-    int dupFd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
-    if (dupFd < 0) {
-        return -errno;
+    int dupFd;
+    if (status_t err = dupFileDescriptor(fd, &dupFd); err != OK) {
+        return err;
     }
     status_t err = writeFileDescriptor(dupFd, true /*takeOwnership*/);
     if (err != OK) {
@@ -1496,9 +1497,9 @@ status_t Parcel::writeParcelFileDescriptor(int fd, bool takeOwnership)
 
 status_t Parcel::writeDupParcelFileDescriptor(int fd)
 {
-    int dupFd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
-    if (dupFd < 0) {
-        return -errno;
+    int dupFd;
+    if (status_t err = dupFileDescriptor(fd, &dupFd); err != OK) {
+        return err;
     }
     status_t err = writeParcelFileDescriptor(dupFd, true /*takeOwnership*/);
     if (err != OK) {
@@ -2295,7 +2296,12 @@ status_t Parcel::readUniqueFileDescriptor(base::unique_fd* val) const
         return BAD_TYPE;
     }
 
-    val->reset(fcntl(got, F_DUPFD_CLOEXEC, 0));
+    int dupFd;
+    if (status_t err = dupFileDescriptor(got, &dupFd); err != OK) {
+        return BAD_VALUE;
+    }
+
+    val->reset(dupFd);
 
     if (val->get() < 0) {
         return BAD_VALUE;
@@ -2312,7 +2318,12 @@ status_t Parcel::readUniqueParcelFileDescriptor(base::unique_fd* val) const
         return BAD_TYPE;
     }
 
-    val->reset(fcntl(got, F_DUPFD_CLOEXEC, 0));
+    int dupFd;
+    if (status_t err = dupFileDescriptor(got, &dupFd); err != OK) {
+        return BAD_VALUE;
+    }
+
+    val->reset(dupFd);
 
     if (val->get() < 0) {
         return BAD_VALUE;