[flang-commits] [flang] e5a4f73 - [flang][runtime] OPEN write-only files

[Peter Klausler via flang-commits]

Author: Peter Klausler
Date: 2022-06-03T18:09:40-07:00
New Revision: e5a4f730dafd9a6dc2371d6e414540fa0fd15460

URL: https://github.com/llvm/llvm-project/commit/e5a4f730dafd9a6dc2371d6e414540fa0fd15460
DIFF: https://github.com/llvm/llvm-project/commit/e5a4f730dafd9a6dc2371d6e414540fa0fd15460.diff

LOG: [flang][runtime] OPEN write-only files

If a file being opened with no ACTION= is write-only then cope with
it rather than defaulting prematurely to treating it as read-only.

Differential Revision: https://reviews.llvm.org/D127015

Added: 
    

Modified: 
    flang/runtime/file.cpp

Removed: 
    


################################################################################
diff  --git a/flang/runtime/file.cpp b/flang/runtime/file.cpp
index 6a86c9ddfc5d..fa040b417c31 100644
--- a/flang/runtime/file.cpp
+++ b/flang/runtime/file.cpp
@@ -97,12 +97,18 @@ void OpenFile::Open(OpenStatus status, std::optional<Action> action,
       flags |= O_TRUNC;
     }
     if (!action) {
-      // Try to open read/write, back off to read-only on failure
+      // Try to open read/write, back off to read-only or even write-only
+      // on failure
       fd_ = ::open(path_.get(), flags | O_RDWR, 0600);
       if (fd_ >= 0) {
         action = Action::ReadWrite;
       } else {
-        action = Action::Read;
+        fd_ = ::open(path_.get(), flags | O_RDONLY, 0600);
+        if (fd_ >= 0) {
+          action = Action::Read;
+        } else {
+          action = Action::Write;
+        }
       }
     }
     if (fd_ < 0) {