From 0359d6d12314e46e45f16cccca7e0b38046d2e1c Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Thu, 13 Oct 2022 21:35:16 +0200 Subject: [PATCH] Fix error display if execve() in the builder fails After we've send "\2\n" to the parent, we can't send a serialized exception anymore. It will show up garbled like $ nix-build --store /tmp/nix --expr 'derivation { name = "foo"; system = "x86_64-linux"; builder = "/foo/bar"; }' this derivation will be built: /nix/store/xmdip0z5x1zqpp6gnxld3vqng7zbpapp-foo.drv building '/nix/store/xmdip0z5x1zqpp6gnxld3vqng7zbpapp-foo.drv'... ErrorErrorEexecuting '/foo/bar': No such file or directory error: builder for '/nix/store/xmdip0z5x1zqpp6gnxld3vqng7zbpapp-foo.drv' failed with exit code 1 --- src/libstore/build/local-derivation-goal.cc | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc index 18b682e13..5cea3b590 100644 --- a/src/libstore/build/local-derivation-goal.cc +++ b/src/libstore/build/local-derivation-goal.cc @@ -1594,6 +1594,8 @@ void LocalDerivationGoal::runChild() /* Warning: in the child we should absolutely not make any SQLite calls! */ + bool sendException = true; + try { /* child */ commonChildInit(builderOut); @@ -2050,6 +2052,8 @@ void LocalDerivationGoal::runChild() /* Indicate that we managed to set up the build environment. */ writeFull(STDERR_FILENO, std::string("\2\n")); + sendException = false; + /* Execute the program. This should not return. */ if (drv->isBuiltin()) { try { @@ -2103,10 +2107,13 @@ void LocalDerivationGoal::runChild() throw SysError("executing '%1%'", drv->builder); } catch (Error & e) { - writeFull(STDERR_FILENO, "\1\n"); - FdSink sink(STDERR_FILENO); - sink << e; - sink.flush(); + if (sendException) { + writeFull(STDERR_FILENO, "\1\n"); + FdSink sink(STDERR_FILENO); + sink << e; + sink.flush(); + } else + std::cerr << e.msg(); _exit(1); } }