Add a new flag --sandbox_writable_path, which asks the sandbox to make an

existing directory writable when running actions.

RELNOTES: Added a new flag --sandbox_writable_path, which asks the sandbox to
make an existing directory writable when running actions.
PiperOrigin-RevId: 157971858

2 files changed, 16 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/sandbox/SandboxOptions.java b/src/main/java/com/google/devtools/build/lib/sandbox/SandboxOptions.java
index 437d1ae4a1..3c074aaf70 100644
--- a/src/main/java/com/google/devtools/build/lib/sandbox/SandboxOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/sandbox/SandboxOptions.java
@@ -133,6 +133,16 @@ public class SandboxOptions extends OptionsBase {
   public List<String> sandboxTmpfsPath;
 
   @Option(
+      name = "sandbox_writable_path",
+      allowMultiple = true,
+      defaultValue = "",
+      category = "config",
+      help = "For sandboxed actions, make an existing directory writable in the sandbox"
+          + " (if supported by the sandboxing implementation, ignored otherwise)."
+  )
+  public List<String> sandboxWritablePath;
+
+  @Option(
     name = "sandbox_add_mount_pair",
     allowMultiple = true,
     converter = MountPairConverter.class,
diff --git a/src/main/java/com/google/devtools/build/lib/sandbox/SandboxStrategy.java b/src/main/java/com/google/devtools/build/lib/sandbox/SandboxStrategy.java
index c0ab7fd0fd..b80066bb56 100644
--- a/src/main/java/com/google/devtools/build/lib/sandbox/SandboxStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/sandbox/SandboxStrategy.java
@@ -201,6 +201,12 @@ abstract class SandboxStrategy implements SandboxedSpawnActionContext {
       // needed directory if it doesn't exist yet.
       writablePaths.add(sandboxExecRoot.getRelative(env.get("TEST_TMPDIR")));
     }
+
+    FileSystem fileSystem = sandboxExecRoot.getFileSystem();
+    for (String writablePath : sandboxOptions.sandboxWritablePath) {
+      writablePaths.add(fileSystem.getPath(writablePath));
+    }
+
     return writablePaths.build();
   }