From e0d2eb5a798613f9c24ad0056da86c8cfd19043d Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 26 Jun 2017 11:52:14 -0300 Subject: [PATCH] linux: Implement tmpfile with O_TMPFILE (BZ#21530) This patch adds O_TMPFILE support to tmpfile on Linux. This is similar to the previous suggestion by Andreas Schwab [1] with the difference the file descriptor creation is parameterized to compartmentalize Linux only open flags (O_TMPFILE) on sysdeps. Checked on x86_64-linux-gnu. Adhemerval Zanella Andreas Schwab [BZ #21530] * include/stdio.h (__gen_tempfd): New function. * stdio-common/Makefile (routines): Add gentempfd. * stdio-common/gentempfd.c: New file. * sysdeps/unix/sysv/linux/gentempfd.c: Likewise. * stdio-common/tmpfile.c (tmpfile): First try to use a system specific unnamed file first. [1] https://sourceware.org/ml/libc-alpha/2017-06/msg01293.html --- ChangeLog | 11 ++++++++++ include/stdio.h | 3 +++ stdio-common/Makefile | 2 +- stdio-common/gentempfd.c | 26 ++++++++++++++++++++++ stdio-common/tmpfile.c | 26 ++++++++++++++-------- sysdeps/unix/sysv/linux/gentempfd.c | 34 +++++++++++++++++++++++++++++ 6 files changed, 92 insertions(+), 10 deletions(-) create mode 100644 stdio-common/gentempfd.c create mode 100644 sysdeps/unix/sysv/linux/gentempfd.c diff --git a/ChangeLog b/ChangeLog index 785b7e9e10..4f8a12ca7c 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,14 @@ +2017-09-01 Adhemerval Zanella + Andreas Schwab + + [BZ #21530] + * include/stdio.h (__gen_tempfd): New function. + * stdio-common/Makefile (routines): Add gentempfd. + * stdio-common/gentempfd.c: New file. + * sysdeps/unix/sysv/linux/gentempfd.c: Likewise. + * stdio-common/tmpfile.c (tmpfile): First try to use a system specific + unnamed file first. + 2017-09-01 Florian Weimer [BZ #21915] diff --git a/include/stdio.h b/include/stdio.h index 509447c528..87e0e10797 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -191,5 +191,8 @@ 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 397e0c2579..2c3c2e5d11 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 0000000000..d40c57dd89 --- /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 + . */ + +#include + +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 e6030be0af..c5cbb688f4 100644 --- a/stdio-common/tmpfile.c +++ b/stdio-common/tmpfile.c @@ -34,23 +34,31 @@ 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]; + + 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); + /* Note that this relies on the Unix semantics that + a file is not really removed until it is closed. */ + (void) __unlink (buf); + } 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 0000000000..902cbe286e --- /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 + . */ + +#include +#include +#include + +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) -- 2.43.5