From 2726b8f439601389d4e01839982d3a01cd51849d Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Wed, 7 Oct 2009 13:36:45 -0600 Subject: [PATCH] utimens: add lutimens interface Wraps utimensat(,AT_SYMLINK_NOFOLLOW) or lutimes, when supported; otherwise fail with ENOSYS. Allows coreutils' copy.c to preserve symlink timestamps on more systems. Note that cygwin's lstat changes atime of symlinks, but mtime can reliably be set. * lib/utimens.c (lutimens): New function. * m4/utimens.m4 (gl_UTIMENS): Check for lutimes. * lib/utimens.h (lutimens): Declare new interface. * tests/test-utimens.c (main): Enhance test. * tests/test-lutimens.h (test_lutimens): New file. * modules/utimens-tests (Files): Distribute it. (Depends-on): Add symlink. (configure.ac): Check for usleep. Signed-off-by: Eric Blake --- ChangeLog | 10 ++++ lib/utimens.c | 60 ++++++++++++++++++++ lib/utimens.h | 1 + m4/utimens.m4 | 8 +-- modules/utimens-tests | 3 + tests/test-lutimens.h | 152 ++++++++++++++++++++++++++++++++++++++++++++++++++ tests/test-utimens.c | 13 ++++- 7 files changed, 242 insertions(+), 5 deletions(-) create mode 100644 tests/test-lutimens.h diff --git a/ChangeLog b/ChangeLog index ffbfe70ba..39cc9bd8a 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,15 @@ 2009-10-10 Eric Blake + utimens: add lutimens interface + * lib/utimens.c (lutimens): New function. + * m4/utimens.m4 (gl_UTIMENS): Check for lutimes. + * lib/utimens.h (lutimens): Declare new interface. + * tests/test-utimens.c (main): Enhance test. + * tests/test-lutimens.h (test_lutimens): New file. + * modules/utimens-tests (Files): Distribute it. + (Depends-on): Add symlink. + (configure.ac): Check for usleep. + utimens: validate futimens usage * lib/utimens.c (gl_futimens): Require valid fd up front, using fewer syscalls on failure later on. Avoid compiler warning on diff --git a/lib/utimens.c b/lib/utimens.c index b1ac350c3..eb5102ee8 100644 --- a/lib/utimens.c +++ b/lib/utimens.c @@ -207,3 +207,63 @@ utimens (char const *file, struct timespec const timespec[2]) { return gl_futimens (-1, file, timespec); } + +/* Set the access and modification time stamps of the symlink FILE to + be TIMESPEC[0] and TIMESPEC[1], respectively. Fail with ENOSYS if + the platform does not support changing symlink timestamps. */ +int +lutimens (char const *file _UNUSED_PARAMETER_, + struct timespec const timespec[2] _UNUSED_PARAMETER_) +{ + /* The Linux kernel did not support symlink timestamps until + utimensat, in version 2.6.22, so we don't need to mimic + gl_futimens' worry about buggy NFS clients. But we do have to + worry about bogus return values. */ + +#if HAVE_UTIMENSAT + { + int result = utimensat (AT_FDCWD, file, timespec, AT_SYMLINK_NOFOLLOW); +# ifdef __linux__ + /* Work around a kernel bug: + http://bugzilla.redhat.com/442352 + http://bugzilla.redhat.com/449910 + It appears that utimensat can mistakenly return 280 rather + than -1 upon ENOSYS failure. + FIXME: remove in 2010 or whenever the offending kernels + are no longer in common use. */ + if (0 < result) + errno = ENOSYS; +# endif + + if (result == 0 || errno != ENOSYS) + return result; + } +#endif /* HAVE_UTIMENSAT */ + + /* The platform lacks an interface to set file timestamps with + nanosecond resolution, so do the best we can, discarding any + fractional part of the timestamp. */ +#if HAVE_LUTIMES + { + struct timeval timeval[2]; + struct timeval const *t; + if (timespec) + { + timeval[0].tv_sec = timespec[0].tv_sec; + timeval[0].tv_usec = timespec[0].tv_nsec / 1000; + timeval[1].tv_sec = timespec[1].tv_sec; + timeval[1].tv_usec = timespec[1].tv_nsec / 1000; + t = timeval; + } + else + t = NULL; + + return lutimes (file, t); + } +#endif /* HAVE_LUTIMES */ + + /* Out of luck. Symlink timestamps can't be changed. We won't + bother changing the timestamps if FILE was not a symlink. */ + errno = ENOSYS; + return -1; +} diff --git a/lib/utimens.h b/lib/utimens.h index 169521da7..8b3ccef5e 100644 --- a/lib/utimens.h +++ b/lib/utimens.h @@ -1,3 +1,4 @@ #include int gl_futimens (int, char const *, struct timespec const [2]); int utimens (char const *, struct timespec const [2]); +int lutimens (char const *, struct timespec const [2]); diff --git a/m4/utimens.m4 b/m4/utimens.m4 index 01a3184ce..381d087d2 100644 --- a/m4/utimens.m4 +++ b/m4/utimens.m4 @@ -1,10 +1,10 @@ -dnl Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Free Software -dnl Foundation, Inc. +dnl Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free +dnl Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. -dnl serial 2 +dnl serial 3 AC_DEFUN([gl_UTIMENS], [ @@ -14,5 +14,5 @@ AC_DEFUN([gl_UTIMENS], AC_REQUIRE([gl_FUNC_UTIMES]) AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC]) AC_REQUIRE([gl_CHECK_TYPE_STRUCT_UTIMBUF]) - AC_CHECK_FUNCS_ONCE([futimes futimesat futimens utimensat]) + AC_CHECK_FUNCS_ONCE([futimes futimesat futimens utimensat lutimes]) ]) diff --git a/modules/utimens-tests b/modules/utimens-tests index 9163b0453..85b9f657c 100644 --- a/modules/utimens-tests +++ b/modules/utimens-tests @@ -1,15 +1,18 @@ Files: tests/test-futimens.h +tests/test-lutimens.h tests/test-utimens.h tests/test-utimens.c Depends-on: stat-time stdbool +symlink timespec utimecmp configure.ac: +AC_CHECK_FUNCS_ONCE([usleep]) Makefile.am: TESTS += test-utimens diff --git a/tests/test-lutimens.h b/tests/test-lutimens.h new file mode 100644 index 000000000..18cf75fa2 --- /dev/null +++ b/tests/test-lutimens.h @@ -0,0 +1,152 @@ +/* Test of file timestamp modification functions. + Copyright (C) 2009 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +/* This file assumes that BASE and ASSERT are already defined. */ + +#ifndef GL_TEST_UTIMENS +# define GL_TEST_UTIMENS + +#include +#include +#include +#include + +#include "stat-time.h" +#include "timespec.h" +#include "utimecmp.h" + +enum { + BILLION = 1000 * 1000 * 1000, + + Y2K = 946684800, /* Jan 1, 2000, in seconds since epoch. */ + + /* Bogus positive and negative tv_nsec values closest to valid + range, but without colliding with UTIME_NOW or UTIME_OMIT. */ + UTIME_BOGUS_POS = BILLION + ((UTIME_NOW == BILLION || UTIME_OMIT == BILLION) + ? (1 + (UTIME_NOW == BILLION + 1) + + (UTIME_OMIT == BILLION + 1)) + : 0), + UTIME_BOGUS_NEG = -1 - ((UTIME_NOW == -1 || UTIME_OMIT == -1) + ? (1 + (UTIME_NOW == -2) + (UTIME_OMIT == -2)) + : 0) +}; + +#endif /* GL_TEST_UTIMENS */ + +/* This function is designed to test both lutimens(a,b) and + utimensat(AT_FDCWD,a,b,AT_SYMLINK_NOFOLLOW). FUNC is the function + to test. If PRINT, warn before skipping tests with status 77. */ +static int +test_lutimens (int (*func) (char const *, struct timespec const *), bool print) +{ + int result; + struct stat st1; + struct stat st2; + bool atime_supported = true; + + if (symlink ("nowhere", BASE "link")) + { + if (print) + fputs ("skipping test: symlinks not supported on this file system\n", + stderr); + return 77; + } + errno = 0; + result = func (BASE "link", NULL); + if (result == -1 && errno == ENOSYS) + { + ASSERT (unlink (BASE "link") == 0); + if (print) + fputs ("skipping test: " + "setting symlink time not supported on this file system\n", + stderr); + return 77; + } + ASSERT (!result); + ASSERT (lstat (BASE "link", &st1) == 0); +#if HAVE_USLEEP + /* On Cygwin, the mere act of lstat changes symlink atime, even + though POSIX says that only readlink is allowed to do that. + Sleeping for one millisecond is enough to expose this. Platforms + without usleep either don't have symlinks, or are immune. */ + usleep (1000); +#endif + ASSERT (lstat (BASE "link", &st2) == 0); + if (st1.st_atime != st2.st_atime + || get_stat_atime_ns (&st1) != get_stat_atime_ns (&st2)) + atime_supported = false; + + /* Invalid arguments. */ + errno = 0; + ASSERT (func ("no_such", NULL) == -1); + ASSERT (errno == ENOENT); + errno = 0; + ASSERT (func ("", NULL) == -1); + ASSERT (errno == ENOENT); + { + struct timespec ts[2] = { { Y2K, UTIME_BOGUS_POS }, { Y2K, 0 } }; + errno = 0; + ASSERT (func (BASE "link", ts) == -1); + ASSERT (errno == EINVAL); + } + { + struct timespec ts[2] = { { Y2K, 0 }, { Y2K, UTIME_BOGUS_NEG } }; + errno = 0; + ASSERT (func (BASE "link", ts) == -1); + ASSERT (errno == EINVAL); + } + ASSERT (lstat (BASE "link", &st2) == 0); + if (atime_supported) + { + ASSERT (st1.st_atime == st2.st_atime); + ASSERT (get_stat_atime_ns (&st1) == get_stat_atime_ns (&st2)); + } + ASSERT (utimecmp (BASE "link", &st1, &st2, 0) == 0); + + /* Set both times. */ + { + struct timespec ts[2] = { { Y2K, BILLION / 2 - 1 }, { Y2K, BILLION - 1 } }; + ASSERT (func (BASE "link", ts) == 0); + ASSERT (lstat (BASE "link", &st2) == 0); + if (atime_supported) + { + ASSERT (st2.st_atime == Y2K); + ASSERT (0 <= get_stat_atime_ns (&st2)); + ASSERT (get_stat_atime_ns (&st2) < BILLION / 2); + } + ASSERT (st2.st_mtime == Y2K); + ASSERT (0 <= get_stat_mtime_ns (&st2)); + ASSERT (get_stat_mtime_ns (&st2) < BILLION); + } + + /* Play with UTIME_OMIT, UTIME_NOW. */ + { + struct timespec ts[2] = { { BILLION, UTIME_OMIT }, { 0, UTIME_NOW } }; + ASSERT (func (BASE "link", ts) == 0); + ASSERT (lstat (BASE "link", &st2) == 0); + if (atime_supported) + { + ASSERT (st2.st_atime == Y2K); + ASSERT (0 <= get_stat_atime_ns (&st2)); + ASSERT (get_stat_atime_ns (&st2) < BILLION / 2); + } + ASSERT (utimecmp (BASE "link", &st1, &st2, 0) <= 0); + } + + /* Cleanup. */ + ASSERT (unlink (BASE "link") == 0); + return 0; +} diff --git a/tests/test-utimens.c b/tests/test-utimens.c index 5734a570a..0b00fadb4 100644 --- a/tests/test-utimens.c +++ b/tests/test-utimens.c @@ -39,6 +39,7 @@ #define BASE "test-utimens.t" #include "test-futimens.h" +#include "test-lutimens.h" #include "test-utimens.h" /* Wrap gl_futimens to behave like futimens. */ @@ -70,10 +71,20 @@ do_fdutimens (char const *name, struct timespec const times[2]) int main () { + int result1; + int result2; + /* Clean up any trash from prior testsuite runs. */ ASSERT (system ("rm -rf " BASE "*") == 0); ASSERT (test_utimens (utimens) == 0); ASSERT (test_utimens (do_fdutimens) == 0); - return test_futimens (do_futimens, true); + result1 = test_futimens (do_futimens, true); + if (result1) + ASSERT (result1 == 77); + /* Print only one skip message. */ + result2 = test_lutimens (lutimens, result1 == 0); + if (result2) + ASSERT (result2 == 77); + return result1 | result2; } -- 2.11.0