From a336b835ee0831ba5fe2f4e8f9b1773eff68416b Mon Sep 17 00:00:00 2001
From: Maksim Denisov <denisov.maksim@huawei.com>
Date: Fri, 12 Jul 2024 11:08:15 +0200
Subject: Store newly spliced executables as copies.

During multithreaded splicing, the main process can be forked (inheriting open file descriptors). In this case, the executable file saved using hardlinking becomes inaccessible. To prevent this, executables must be stored as copies made in a child process.
---
 src/buildtool/storage/local_cas.tpp | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/buildtool/storage/local_cas.tpp b/src/buildtool/storage/local_cas.tpp
index e0cb3883..97ecf1a3 100644
--- a/src/buildtool/storage/local_cas.tpp
+++ b/src/buildtool/storage/local_cas.tpp
@@ -78,8 +78,16 @@ requires(kIsLocalGeneration) auto LocalCAS<kDoGlobalUplink>::LocalUplinkBlob(
     }
 
     // Uplink blob from older generation to the latest generation.
-    return blob_path_latest.has_value() or
-           latest.StoreBlob</*kOwner=*/true>(*blob_path, is_executable);
+    if (spliced and is_executable) {
+        // During multithreaded splicing, the main process can be forked
+        // (inheriting open file descriptors). In this case, an executable file
+        // saved using hardlinking becomes inaccessible. To prevent this,
+        // executables must be stored as copies made in a child process.
+        return latest.StoreBlob</*kOwner=*/false>(*blob_path, is_executable)
+            .has_value();
+    }
+    return latest.StoreBlob</*kOwner=*/true>(*blob_path, is_executable)
+        .has_value();
 }
 
 template <bool kDoGlobalUplink>
-- 
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