Zygote: Add fdsToIgnore

Add file descriptors that should be ignored in the file descriptor
table check.

Use this to ignore the pipe file descriptors when starting an app
with invoke-with (wrapper).

Bug: 32607405
Test: m
Test: Device boots
Test: Apps start
Test: adb root && adb shell setprop wrap.com.android.calculator2 logwrapper && adb shell am start -S -n com.android.calculator2/.Calculator
Change-Id: I4a30dfc9382d3172cc815bd41b17a123799354f6

2 files changed, 10 insertions, 4 deletions

diff --git a/core/java/com/android/internal/os/Zygote.java b/core/java/com/android/internal/os/Zygote.java
index 293de3d71332..e1e0a21eb7f5 100644
--- a/core/java/com/android/internal/os/Zygote.java
+++ b/core/java/com/android/internal/os/Zygote.java
@@ -85,6 +85,9 @@ public final class Zygote {
      * file descriptor numbers that are to be closed by the child
      * (and replaced by /dev/null) after forking.  An integer value
      * of -1 in any entry in the array means "ignore this one".
+     * @param fdsToIgnore null-ok an array of ints, either null or holding
+     * one or more POSIX file descriptor numbers that are to be ignored
+     * in the file descriptor table check.
      * @param instructionSet null-ok the instruction set to use.
      * @param appDataDir null-ok the data directory of the app.
      *
@@ -93,11 +96,11 @@ public final class Zygote {
      */
     public static int forkAndSpecialize(int uid, int gid, int[] gids, int debugFlags,
           int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose,
-          String instructionSet, String appDataDir) {
+          int[] fdsToIgnore, String instructionSet, String appDataDir) {
         VM_HOOKS.preFork();
         int pid = nativeForkAndSpecialize(
                   uid, gid, gids, debugFlags, rlimits, mountExternal, seInfo, niceName, fdsToClose,
-                  instructionSet, appDataDir);
+                  fdsToIgnore, instructionSet, appDataDir);
         // Enable tracing as soon as possible for the child process.
         if (pid == 0) {
             Trace.setTracingEnabled(true);
@@ -111,7 +114,7 @@ public final class Zygote {
 
     native private static int nativeForkAndSpecialize(int uid, int gid, int[] gids,int debugFlags,
           int[][] rlimits, int mountExternal, String seInfo, String niceName, int[] fdsToClose,
-          String instructionSet, String appDataDir);
+          int[] fdsToIgnore, String instructionSet, String appDataDir);
 
     /**
      * Special method to start the system server process. In addition to the
diff --git a/core/java/com/android/internal/os/ZygoteConnection.java b/core/java/com/android/internal/os/ZygoteConnection.java
index 44c6e8557c2c..ec80303f714a 100644
--- a/core/java/com/android/internal/os/ZygoteConnection.java
+++ b/core/java/com/android/internal/os/ZygoteConnection.java
@@ -193,11 +193,14 @@ class ZygoteConnection {
                 rlimits = parsedArgs.rlimits.toArray(intArray2d);
             }
 
+            int[] fdsToIgnore = null;
+
             if (parsedArgs.invokeWith != null) {
                 FileDescriptor[] pipeFds = Os.pipe2(O_CLOEXEC);
                 childPipeFd = pipeFds[1];
                 serverPipeFd = pipeFds[0];
                 Os.fcntlInt(childPipeFd, F_SETFD, 0);
+                fdsToIgnore = new int[] { childPipeFd.getInt$(), serverPipeFd.getInt$() };
             }
 
             /**
@@ -230,7 +233,7 @@ class ZygoteConnection {
 
             pid = Zygote.forkAndSpecialize(parsedArgs.uid, parsedArgs.gid, parsedArgs.gids,
                     parsedArgs.debugFlags, rlimits, parsedArgs.mountExternal, parsedArgs.seInfo,
-                    parsedArgs.niceName, fdsToClose, parsedArgs.instructionSet,
+                    parsedArgs.niceName, fdsToClose, fdsToIgnore, parsedArgs.instructionSet,
                     parsedArgs.appDataDir);
         } catch (ErrnoException ex) {
             logAndPrintError(newStderr, "Exception creating pipe", ex);