Support outputting to /dev/null.
When writing to a non regular file we cannot rename to it. Since we
have to write, we may as well create a temporary file to avoid trying
to create an unique file in /dev when trying to write to /dev/null.
llvm-svn: 291485
diff --git a/llvm/lib/Support/FileOutputBuffer.cpp b/llvm/lib/Support/FileOutputBuffer.cpp
index 2c7bf04..57e5a8d 100644
--- a/llvm/lib/Support/FileOutputBuffer.cpp
+++ b/llvm/lib/Support/FileOutputBuffer.cpp
@@ -15,6 +15,7 @@
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/Errc.h"
+#include "llvm/Support/Path.h"
#include "llvm/Support/Signals.h"
#include <system_error>
@@ -28,8 +29,10 @@
namespace llvm {
FileOutputBuffer::FileOutputBuffer(std::unique_ptr<mapped_file_region> R,
- StringRef Path, StringRef TmpPath)
- : Region(std::move(R)), FinalPath(Path), TempPath(TmpPath) {}
+ StringRef Path, StringRef TmpPath,
+ bool IsRegular)
+ : Region(std::move(R)), FinalPath(Path), TempPath(TmpPath),
+ IsRegular(IsRegular) {}
FileOutputBuffer::~FileOutputBuffer() {
// Close the mapping before deleting the temp file, so that the removal
@@ -40,9 +43,10 @@
ErrorOr<std::unique_ptr<FileOutputBuffer>>
FileOutputBuffer::create(StringRef FilePath, size_t Size, unsigned Flags) {
- // If file already exists, it must be a regular file (to be mappable).
+ // Check file is not a regular file, in which case we cannot remove it.
sys::fs::file_status Stat;
std::error_code EC = sys::fs::status(FilePath, Stat);
+ bool IsRegular = true;
switch (Stat.type()) {
case sys::fs::file_type::file_not_found:
// If file does not exist, we'll create one.
@@ -56,25 +60,34 @@
default:
if (EC)
return EC;
- else
- return make_error_code(errc::operation_not_permitted);
+ IsRegular = false;
}
- // Delete target file.
- EC = sys::fs::remove(FilePath);
- if (EC)
- return EC;
+ if (IsRegular) {
+ // Delete target file.
+ EC = sys::fs::remove(FilePath);
+ if (EC)
+ return EC;
+ }
- unsigned Mode = sys::fs::all_read | sys::fs::all_write;
- // If requested, make the output file executable.
- if (Flags & F_executable)
- Mode |= sys::fs::all_exe;
-
- // Create new file in same directory but with random name.
SmallString<128> TempFilePath;
int FD;
- EC = sys::fs::createUniqueFile(Twine(FilePath) + ".tmp%%%%%%%", FD,
- TempFilePath, Mode);
+ if (IsRegular) {
+ unsigned Mode = sys::fs::all_read | sys::fs::all_write;
+ // If requested, make the output file executable.
+ if (Flags & F_executable)
+ Mode |= sys::fs::all_exe;
+ // Create new file in same directory but with random name.
+ EC = sys::fs::createUniqueFile(Twine(FilePath) + ".tmp%%%%%%%", FD,
+ TempFilePath, Mode);
+ } else {
+ // Create a temporary file. Since this is a special file, we will not move
+ // it and the new file can be in another filesystem. This avoids trying to
+ // create a temporary file in /dev when outputting to /dev/null for example.
+ EC = sys::fs::createTemporaryFile(sys::path::filename(FilePath), "", FD,
+ TempFilePath);
+ }
+
if (EC)
return EC;
@@ -99,8 +112,8 @@
if (Ret)
return std::error_code(errno, std::generic_category());
- std::unique_ptr<FileOutputBuffer> Buf(
- new FileOutputBuffer(std::move(MappedFile), FilePath, TempFilePath));
+ std::unique_ptr<FileOutputBuffer> Buf(new FileOutputBuffer(
+ std::move(MappedFile), FilePath, TempFilePath, IsRegular));
return std::move(Buf);
}
@@ -108,10 +121,19 @@
// Unmap buffer, letting OS flush dirty pages to file on disk.
Region.reset();
+ std::error_code EC;
+ if (IsRegular) {
+ // Rename file to final name.
+ EC = sys::fs::rename(Twine(TempPath), Twine(FinalPath));
+ sys::DontRemoveFileOnSignal(TempPath);
+ } else {
+ EC = sys::fs::copy_file(TempPath, FinalPath);
+ std::error_code RMEC = sys::fs::remove(TempPath);
+ sys::DontRemoveFileOnSignal(TempPath);
+ if (RMEC)
+ return RMEC;
+ }
- // Rename file to final name.
- std::error_code EC = sys::fs::rename(Twine(TempPath), Twine(FinalPath));
- sys::DontRemoveFileOnSignal(TempPath);
return EC;
}
} // namespace