[newlib-cygwin] Cygwin: Have tmpfile(3) use O_TMPFILE
Corinna Vinschen
corinna@sourceware.org
Fri Feb 12 09:18:42 GMT 2021
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=62ee6581a5701342c17790116f847e9d40c387d7
commit 62ee6581a5701342c17790116f847e9d40c387d7
Author: Mark Geisert <mark@maxrnd.com>
Date: Wed Feb 10 22:53:05 2021 -0800
Cygwin: Have tmpfile(3) use O_TMPFILE
Per discussion on cygwin-developers, a Cygwin tmpfile(3) implementation
has been added to syscalls.cc. This overrides the one supplied by
newlib. Then the open(2) flag O_TMPFILE was added to the open call that
tmpfile internally makes.
This v2 patch removes O_CREAT from open() call as O_TMPFILE obviates it.
Note that open() takes a directory's path but returns an fd to a file.
Diff:
---
winsup/cygwin/release/3.2.0 | 4 ++++
winsup/cygwin/syscalls.cc | 19 +++++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/winsup/cygwin/release/3.2.0 b/winsup/cygwin/release/3.2.0
index f748a9bc8..d02d16863 100644
--- a/winsup/cygwin/release/3.2.0
+++ b/winsup/cygwin/release/3.2.0
@@ -19,6 +19,10 @@ What changed:
- A few FAQ updates.
+- Have tmpfile(3) make use of Win32 FILE_ATTRIBUTE_TEMPORARY via open(2)
+ flag O_TMPFILE.
+ Addresses: https://cygwin.com/pipermail/cygwin/2021-January/247304.html
+
Bug Fixes
---------
diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index 52a020f07..d04b2d9b3 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -5225,3 +5225,22 @@ pipe2 (int filedes[2], int mode)
syscall_printf ("%R = pipe2([%d, %d], %y)", res, read, write, mode);
return res;
}
+
+extern "C" FILE *
+tmpfile (void)
+{
+ char *dir = getenv ("TMPDIR");
+ if (!dir)
+ dir = P_tmpdir;
+ int fd = open (dir, O_RDWR | O_BINARY | O_TMPFILE, S_IRUSR | S_IWUSR);
+ if (fd < 0)
+ return NULL;
+ FILE *fp = fdopen (fd, "wb+");
+ int e = errno;
+ if (!fp)
+ close (fd); // ..will remove tmp file
+ set_errno (e);
+ return fp;
+}
+
+EXPORT_ALIAS (tmpfile, tmpfile64)
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