git: 3358108a38f0 - main - llvm: Support: don't block signals around close if it can be avoided

The branch main has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=3358108a38f0efc7e7a143aeda80c941946fef77

commit 3358108a38f0efc7e7a143aeda80c941946fef77
Author:     Mateusz Guzik <mjg@FreeBSD.org>
AuthorDate: 2023-12-29 18:51:56 +0000
Commit:     Mateusz Guzik <mjg@FreeBSD.org>
CommitDate: 2023-12-29 18:52:12 +0000

    llvm: Support: don't block signals around close if it can be avoided
    
    Signal blocking originally showed up in 51c2afc4b65b2782 ("Support:
    Don't call close again if we get EINTR"), but it was overzealous --
    there are systems where the error is known to be fine.
    
    This commit elides signal blocking for said systems (the list is
    incomplete though).
    
    Note close() can still fail for other reasons (like ENOSPC), in which
    case an error will be returned while the fd slot is cleared up.
    
    Reviewed by: dim
    Differential Revision: https://reviews.freebsd.org/D42984
---
 .../llvm-project/llvm/lib/Support/Unix/Process.inc   | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/contrib/llvm-project/llvm/lib/Support/Unix/Process.inc b/contrib/llvm-project/llvm/lib/Support/Unix/Process.inc
index 2babf07944bf..c8b15cb759df 100644
--- a/contrib/llvm-project/llvm/lib/Support/Unix/Process.inc
+++ b/contrib/llvm-project/llvm/lib/Support/Unix/Process.inc
@@ -235,6 +235,25 @@ std::error_code Process::FixupStandardFileDescriptors() {
   return std::error_code();
 }
 
+// Close a file descriptor while being mindful of EINTR.
+//
+// On Unix systems closing a file descriptor usually starts with removing it
+// from the fd table (or an equivalent structure). This means any error
+// generated past that point will still result in the entry being cleared.
+//
+// Make sure to not bubble up EINTR as there is nothing to do in that case.
+// XXX what about other errors?
+#if defined(__linux__) || defined(__DragonFly__) || defined(__FreeBSD__) || \
+    defined(__NetBSD__) || defined(__OpenBSD__)
+std::error_code Process::SafelyCloseFileDescriptor(int FD) {
+  int EC = 0;
+  if (::close(FD) < 0) {
+    if (errno != EINTR)
+      EC = errno;
+  }
+  return std::error_code(EC, std::generic_category());
+}
+#else
 std::error_code Process::SafelyCloseFileDescriptor(int FD) {
   // Create a signal set filled with *all* signals.
   sigset_t FullSet, SavedSet;
@@ -269,6 +288,7 @@ std::error_code Process::SafelyCloseFileDescriptor(int FD) {
     return std::error_code(ErrnoFromClose, std::generic_category());
   return std::error_code(EC, std::generic_category());
 }
+#endif
 
 bool Process::StandardInIsUserInput() {
   return FileDescriptorIsDisplayed(STDIN_FILENO);