This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH] Implement tmpfile with O_TMPFILE (bug 21530)
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 26 Jun 2017 11:53:47 -0300
- Subject: Re: [PATCH] Implement tmpfile with O_TMPFILE (bug 21530)
- Authentication-results: sourceware.org; auth=none
- References: <mvmbmpbotr9.fsf@suse.de>
On 26/06/2017 08:47, Andreas Schwab wrote:
> If the kernel or the file system does not support O_TMPFILE fall back to
> creating a temporary file based on tmpnam.
>
> [BZ #21530]
> * stdio-common/tmpfile.c (tmpfile) [O_TMPFILE]: Try opening an
> unnamed file first.
> ---
> stdio-common/tmpfile.c | 51 ++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 37 insertions(+), 14 deletions(-)
I would prefer to compartmentalize Linuxism to linux sysdep folder, something
like:
diff --git a/include/stdio.h b/include/stdio.h
index f68f633..92fc0e2 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -181,5 +181,8 @@ libc_hidden_proto (__obstack_vprintf_chk)
extern FILE * __fmemopen (void *buf, size_t len, const char *mode);
libc_hidden_proto (__fmemopen)
+extern int __gen_tempfd (int flags);
+libc_hidden_proto (__gen_tempfd)
+
# endif /* not _ISOMAC */
#endif /* stdio.h */
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 01a6dd0..cc6bb8f 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -39,7 +39,7 @@ routines := \
flockfile ftrylockfile funlockfile \
isoc99_scanf isoc99_vscanf isoc99_fscanf isoc99_vfscanf isoc99_sscanf \
isoc99_vsscanf \
- psiginfo
+ psiginfo gentempfd
aux := errlist siglist printf-parsemb printf-parsewc fxprintf
diff --git a/stdio-common/gentempfd.c b/stdio-common/gentempfd.c
new file mode 100644
index 0000000..d40c57d
--- /dev/null
+++ b/stdio-common/gentempfd.c
@@ -0,0 +1,26 @@
+/* Generate a temporary file descriptor. Generic/POSIX version.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+
+int
+__gen_tempfd (int flags)
+{
+ return -1;
+}
+libc_hidden_def (__gen_tempfd)
diff --git a/stdio-common/tmpfile.c b/stdio-common/tmpfile.c
index e6030be..012659b 100644
--- a/stdio-common/tmpfile.c
+++ b/stdio-common/tmpfile.c
@@ -26,7 +26,6 @@
# define tmpfile __new_tmpfile
#endif
-
/* This returns a new stream opened on a temporary file (generated
by tmpnam). The file is opened with mode "w+b" (binary read/write).
If we couldn't generate a unique filename or the file couldn't
@@ -34,23 +33,34 @@
FILE *
tmpfile (void)
{
- char buf[FILENAME_MAX];
int fd;
FILE *f;
-
- if (__path_search (buf, FILENAME_MAX, NULL, "tmpf", 0))
- return NULL;
int flags = 0;
#ifdef FLAGS
flags = FLAGS;
#endif
- fd = __gen_tempname (buf, 0, flags, __GT_FILE);
+
+ /* First try a system specific method. */
+ fd = __gen_tempfd (flags);
+
if (fd < 0)
- return NULL;
+ {
+ char buf[FILENAME_MAX];
- /* Note that this relies on the Unix semantics that
- a file is not really removed until it is closed. */
- (void) __unlink (buf);
+ if (__path_search (buf, sizeof buf, NULL, "tmpf", 0))
+ return NULL;
+
+ fd = __gen_tempname (buf, 0, flags, __GT_FILE);
+ if (fd < 0)
+ return NULL;
+
+ /* Note that this relies on the Unix semantics that
+ a file is not really removed until it is closed. */
+ (void) __unlink (buf);
+ }
+
+ if (fd < 0)
+ return NULL;
if ((f = __fdopen (fd, "w+b")) == NULL)
__close (fd);
diff --git a/sysdeps/unix/sysv/linux/gentempfd.c b/sysdeps/unix/sysv/linux/gentempfd.c
new file mode 100644
index 0000000..902cbe2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/gentempfd.c
@@ -0,0 +1,34 @@
+/* Generate a temporary file descriptor. Linux version.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+
+int
+__gen_tempfd (int flags)
+{
+ int fd = __open (P_tmpdir, O_RDWR | O_TMPFILE | O_EXCL | flags,
+ S_IRUSR | S_IWUSR);
+ if (fd < 0 && errno == ENOENT && strcmp (P_tmpdir, "/tmp") != 0)
+ fd = __open ("/tmp", O_RDWR | O_TMPFILE | O_EXCL | flags,
+ S_IRUSR | S_IWUSR);
+
+ return fd;
+}
+libc_hidden_def (__gen_tempfd)