diff options
Diffstat (limited to 'lib/utimens.c')
| -rw-r--r-- | lib/utimens.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/lib/utimens.c b/lib/utimens.c new file mode 100644 index 0000000..7e3175a --- /dev/null +++ b/lib/utimens.c @@ -0,0 +1,189 @@ +/* Set file access and modification times. + + Copyright (C) 2003, 2004, 2005, 2006, 2007 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, 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, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Paul Eggert. */ + +/* derived from a function in touch.c */ + +#include <config.h> + +#include "utimens.h" + +#include <errno.h> +#include <fcntl.h> +#include <sys/time.h> +#include <unistd.h> + +#if HAVE_UTIME_H +# include <utime.h> +#endif + +/* Some systems (even some that do have <utime.h>) don't declare this + structure anywhere. */ +#ifndef HAVE_STRUCT_UTIMBUF +struct utimbuf +{ + long actime; + long modtime; +}; +#endif + +/* Some systems don't have ENOSYS. */ +#ifndef ENOSYS +# ifdef ENOTSUP +# define ENOSYS ENOTSUP +# else +/* Some systems don't have ENOTSUP either. */ +# define ENOSYS EINVAL +# endif +#endif + +#ifndef __attribute__ +# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__ +# define __attribute__(x) +# endif +#endif + +#ifndef ATTRIBUTE_UNUSED +# define ATTRIBUTE_UNUSED __attribute__ ((__unused__)) +#endif + +/* Set the access and modification time stamps of FD (a.k.a. FILE) to be + TIMESPEC[0] and TIMESPEC[1], respectively. + FD must be either negative -- in which case it is ignored -- + or a file descriptor that is open on FILE. + If FD is nonnegative, then FILE can be NULL, which means + use just futimes (or equivalent) instead of utimes (or equivalent), + and fail if on an old system without futimes (or equivalent). + If TIMESPEC is null, set the time stamps to the current time. + Return 0 on success, -1 (setting errno) on failure. */ + +int +gl_futimens (int fd ATTRIBUTE_UNUSED, + char const *file, struct timespec const timespec[2]) +{ + /* Some Linux-based NFS clients are buggy, and mishandle time stamps + of files in NFS file systems in some cases. We have no + configure-time test for this, but please see + <http://bugs.gentoo.org/show_bug.cgi?id=132673> for references to + some of the problems with Linux 2.6.16. If this affects you, + compile with -DHAVE_BUGGY_NFS_TIME_STAMPS; this is reported to + help in some cases, albeit at a cost in performance. But you + really should upgrade your kernel to a fixed version, since the + problem affects many applications. */ + +#if HAVE_BUGGY_NFS_TIME_STAMPS + if (fd < 0) + sync (); + else + fsync (fd); +#endif + + /* There's currently no interface to set file timestamps with + nanosecond resolution, so do the best we can, discarding any + fractional part of the timestamp. */ +#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES + 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; + + + if (fd < 0) + { +# if HAVE_FUTIMESAT + return futimesat (AT_FDCWD, file, t); +# endif + } + else + { + /* If futimesat or futimes fails here, don't try to speed things + up by returning right away. glibc can incorrectly fail with + errno == ENOENT if /proc isn't mounted. Also, Mandrake 10.0 + in high security mode doesn't allow ordinary users to read + /proc/self, so glibc incorrectly fails with errno == EACCES. + If errno == EIO, EPERM, or EROFS, it's probably safe to fail + right away, but these cases are rare enough that they're not + worth optimizing, and who knows what other messed-up systems + are out there? So play it safe and fall back on the code + below. */ +# if HAVE_FUTIMESAT + if (futimesat (fd, NULL, t) == 0) + return 0; +# elif HAVE_FUTIMES + if (futimes (fd, t) == 0) + return 0; +# endif + } +#endif + + if (!file) + { +#if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES)) + errno = ENOSYS; +#endif + + /* Prefer EBADF to ENOSYS if both error numbers apply. */ + if (errno == ENOSYS) + { + int fd2 = dup (fd); + int dup_errno = errno; + if (0 <= fd2) + close (fd2); + errno = (fd2 < 0 && dup_errno == EBADF ? EBADF : ENOSYS); + } + + return -1; + } + +#if HAVE_WORKING_UTIMES + return utimes (file, t); +#else + { + struct utimbuf utimbuf; + struct utimbuf const *ut; + if (timespec) + { + utimbuf.actime = timespec[0].tv_sec; + utimbuf.modtime = timespec[1].tv_sec; + ut = &utimbuf; + } + else + ut = NULL; + + return utime (file, ut); + } +#endif +} + +/* Set the access and modification time stamps of FILE to be + TIMESPEC[0] and TIMESPEC[1], respectively. */ +int +utimens (char const *file, struct timespec const timespec[2]) +{ + return gl_futimens (-1, file, timespec); +} |