Add runtime option -Xbootclasspathfds: for pre-opened fds

The new option allows the client to pass a pre-opened fds to the
runtime. The number of elements must match the number of BCP jars
specified in -Xbootclasspath. An fd of negative number is a valid
option, in such case the runtime will still open the jar in the
corresponding path in -Xbootclasspath.

Example: -Xbootclasspathfds:10:11:-1:12

The option is currently only used in "unstarted runtime", but will also
be used elsewhere in the follow-up changes.

Bug: 187327262
Test: patch odrefresh to use the option, no longer seeing such openat(2)
Test: m test-art-host-gtest

Change-Id: I1bebbd80136419c03ac1309a8cb8229a0fd69838

1 files changed, 8 insertions, 0 deletions

diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 35b7055275..d54ef6bd30 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -1394,6 +1394,13 @@ bool Runtime::Init(RuntimeArgumentMap&& runtime_options_in) {
     }
   }
 
+  boot_class_path_fds_ = runtime_options.ReleaseOrDefault(Opt::BootClassPathFds);
+  if (!boot_class_path_fds_.empty() && boot_class_path_fds_.size() != boot_class_path_.size()) {
+    LOG(ERROR) << "Number of FDs specified in -Xbootclasspathfds must match the number of JARs in "
+               << "-Xbootclasspath.";
+    return false;
+  }
+
   class_path_string_ = runtime_options.ReleaseOrDefault(Opt::ClassPath);
   properties_ = runtime_options.ReleaseOrDefault(Opt::PropertiesList);
 
@@ -1517,6 +1524,7 @@ bool Runtime::Init(RuntimeArgumentMap&& runtime_options_in) {
                        runtime_options.GetOrDefault(Opt::NonMovingSpaceCapacity),
                        GetBootClassPath(),
                        GetBootClassPathLocations(),
+                       GetBootClassPathFds(),
                        image_locations_,
                        instruction_set_,
                        // Override the collector type to CC if the read barrier config.