* [PATCH v2] Cygwin: Have tmpfile(3) use O_TMPFILE
@ 2021-02-11 6:53 Mark Geisert
2021-02-12 9:20 ` Corinna Vinschen
0 siblings, 1 reply; 3+ messages in thread
From: Mark Geisert @ 2021-02-11 6:53 UTC (permalink / raw)
To: cygwin-patches
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
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] Cygwin: Have tmpfile(3) use O_TMPFILE
2021-02-11 6:53 [PATCH v2] Cygwin: Have tmpfile(3) use O_TMPFILE Mark Geisert
@ 2021-02-12 9:20 ` Corinna Vinschen
2021-02-12 10:15 ` Mark Geisert
0 siblings, 1 reply; 3+ messages in thread
From: Corinna Vinschen @ 2021-02-12 9:20 UTC (permalink / raw)
To: cygwin-patches
On Feb 10 22:53, Mark Geisert wrote:
> 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;
> +}
The patch was missing the EXPORT_ALIAS for tmpfile64, as outlined in
https://cygwin.com/pipermail/cygwin-developers/2021-February/012039.html
I added this to the patch and pushed it.
Thanks,
Corinna
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2021-02-11 6:53 [PATCH v2] Cygwin: Have tmpfile(3) use O_TMPFILE Mark Geisert
2021-02-12 9:20 ` Corinna Vinschen
2021-02-12 10:15 ` Mark Geisert
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