[sanitizer_common] child_stdin_fd_ should only be set on posix_spawn path (#171508)
#170809 added the child_stdin_fd_ field on SymbolizerProcess to allow
the parent process to hold on to the read in of the child's stdin pipe.
This was to avoid SIGPIPE.
However, the `StartSubprocess` path still closes the stdin fd in the
parent here:
https://github.com/llvm/llvm-project/blob/7f5ed91684c808444ede24eb01ad9af73b5806e5/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp#L525-L535
This could cause a double-close of this fd (problematic in the case of
fd reuse).
This moves the `child_stdin_fd_` field to only be initialized on the
posix_spawn path. This should ensure #170809 only truly affects Darwin.
NOKEYCHECK=True
GitOrigin-RevId: 926cbddc185e035a4266f25203e81eec8960f114
diff --git a/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp b/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
index 29c73e3..ab6aee7 100644
--- a/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
+++ b/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cpp
@@ -176,6 +176,10 @@
internal_close(outfd[1]);
return false;
}
+
+ // We intentionally hold on to the read-end so that we don't get a SIGPIPE
+ child_stdin_fd_ = outfd[0];
+
# else // SANITIZER_APPLE
UNIMPLEMENTED();
# endif // SANITIZER_APPLE
@@ -192,9 +196,6 @@
input_fd_ = infd[0];
output_fd_ = outfd[1];
- // We intentionally hold on to the read-end so that we don't get a SIGPIPE
- child_stdin_fd_ = outfd[0];
-
CHECK_GT(pid, 0);
// Check that symbolizer subprocess started successfully.
