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. --- winsup/cygwin/release/3.2.0 | 4 ++++ winsup/cygwin/syscalls.cc | 17 +++++++++++++++++ 2 files changed, 21 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..4cda69033 100644 --- a/winsup/cygwin/syscalls.cc +++ b/winsup/cygwin/syscalls.cc @@ -5225,3 +5225,20 @@ 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; +} -- 2.30.0
