X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Futimens.c;h=44a33c1d791f73336f6ec69edb1049b244a1503f;hb=5191b3546cfb6c163228c23f214e325ddf60d46f;hp=bdb5a25ae61856a490232eaedbd1cbfa41091a94;hpb=41c44a66101c6c14b4e7f151247d517579760ba9;p=gnulib.git diff --git a/lib/utimens.c b/lib/utimens.c index bdb5a25ae..44a33c1d7 100644 --- a/lib/utimens.c +++ b/lib/utimens.c @@ -1,6 +1,6 @@ /* Set file access and modification times. - Copyright (C) 2003-2010 Free Software Foundation, Inc. + Copyright (C) 2003-2013 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 @@ -21,6 +21,7 @@ #include +#define _GL_UTIMENS_INLINE _GL_EXTERN_INLINE #include "utimens.h" #include @@ -89,10 +90,12 @@ validate_timespec (struct timespec timespec[2]) assert (timespec); if ((timespec[0].tv_nsec != UTIME_NOW && timespec[0].tv_nsec != UTIME_OMIT - && (timespec[0].tv_nsec < 0 || 1000000000 <= timespec[0].tv_nsec)) + && ! (0 <= timespec[0].tv_nsec + && timespec[0].tv_nsec < TIMESPEC_RESOLUTION)) || (timespec[1].tv_nsec != UTIME_NOW && timespec[1].tv_nsec != UTIME_OMIT - && (timespec[1].tv_nsec < 0 || 1000000000 <= timespec[1].tv_nsec))) + && ! (0 <= timespec[1].tv_nsec + && timespec[1].tv_nsec < TIMESPEC_RESOLUTION))) { errno = EINVAL; return -1; @@ -164,7 +167,7 @@ update_timespec (struct stat const *statbuf, struct timespec *ts[2]) Return 0 on success, -1 (setting errno) on failure. */ int -fdutimens (char const *file, int fd, struct timespec const timespec[2]) +fdutimens (int fd, char const *file, struct timespec const timespec[2]) { struct timespec adjusted_timespec[2]; struct timespec *ts = timespec ? adjusted_timespec : NULL; @@ -180,18 +183,13 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2]) if (adjustment_needed < 0) return -1; - /* Require that at least one of FD or FILE are valid. Works around + /* Require that at least one of FD or FILE are potentially valid, to avoid a Linux bug where futimens (AT_FDCWD, NULL) changes "." rather than failing. */ - if (!file) + if (fd < 0 && !file) { - if (fd < 0) - { - errno = EBADF; - return -1; - } - if (dup2 (fd, fd) != fd) - return -1; + errno = EBADF; + return -1; } /* Some Linux-based NFS clients are buggy, and mishandle time stamps @@ -220,15 +218,19 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2]) if (0 <= utimensat_works_really) { int result; -# if __linux__ +# if __linux__ || __sun /* As recently as Linux kernel 2.6.32 (Dec 2009), several file systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT, but work if both times are either explicitly specified or UTIME_NOW. Work around it with a preparatory [f]stat prior to calling futimens/utimensat; fortunately, there is not much timing impact due to the extra syscall even on file systems - where UTIME_OMIT would have worked. FIXME: Simplify this in - 2012, when file system bugs are no longer common. */ + where UTIME_OMIT would have worked. + + The same bug occurs in Solaris 11.1 (Apr 2013). + + FIXME: Simplify this for Linux in 2016 and for Solaris in + 2024, when file system bugs are no longer common. */ if (adjustment_needed == 2) { if (fd < 0 ? stat (file, &st) : fstat (fd, &st)) @@ -240,7 +242,7 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2]) /* Note that st is good, in case utimensat gives ENOSYS. */ adjustment_needed++; } -# endif /* __linux__ */ +# endif # if HAVE_UTIMENSAT if (fd < 0) { @@ -300,7 +302,7 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2]) { #if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES struct timeval timeval[2]; - struct timeval const *t; + struct timeval *t; if (ts) { timeval[0].tv_sec = ts[0].tv_sec; @@ -330,12 +332,53 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2]) 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 && !FUTIMESAT_NULL_BUG - if (futimesat (fd, NULL, t) == 0) - return 0; -# elif HAVE_FUTIMES + +# if (HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG) || HAVE_FUTIMES +# if HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG +# undef futimes +# define futimes(fd, t) futimesat (fd, NULL, t) +# endif if (futimes (fd, t) == 0) - return 0; + { +# if __linux__ && __GLIBC__ + /* Work around a longstanding glibc bug, still present as + of 2010-12-27. On older Linux kernels that lack both + utimensat and utimes, glibc's futimes rounds instead of + truncating when falling back on utime. The same bug + occurs in futimesat with a null 2nd arg. */ + if (t) + { + bool abig = 500000 <= t[0].tv_usec; + bool mbig = 500000 <= t[1].tv_usec; + if ((abig | mbig) && fstat (fd, &st) == 0) + { + /* If these two subtractions overflow, they'll + track the overflows inside the buggy glibc. */ + time_t adiff = st.st_atime - t[0].tv_sec; + time_t mdiff = st.st_mtime - t[1].tv_sec; + + struct timeval *tt = NULL; + struct timeval truncated_timeval[2]; + truncated_timeval[0] = t[0]; + truncated_timeval[1] = t[1]; + if (abig && adiff == 1 && get_stat_atime_ns (&st) == 0) + { + tt = truncated_timeval; + tt[0].tv_usec = 0; + } + if (mbig && mdiff == 1 && get_stat_mtime_ns (&st) == 0) + { + tt = truncated_timeval; + tt[1].tv_usec = 0; + } + if (tt) + futimes (fd, tt); + } + } +# endif + + return 0; + } # endif } #endif /* HAVE_FUTIMESAT || HAVE_WORKING_UTIMES */ @@ -370,28 +413,12 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2]) } } -/* 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, char const *file, struct timespec const timespec[2]) -{ - return fdutimens (file, fd, timespec); -} - /* 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 fdutimens (file, -1, timespec); + return fdutimens (-1, file, timespec); } /* Set the access and modification time stamps of FILE to be @@ -417,22 +444,26 @@ lutimens (char const *file, struct timespec const timespec[2]) /* 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 + fdutimens' worry about buggy NFS clients. But we do have to worry about bogus return values. */ #if HAVE_UTIMENSAT if (0 <= lutimensat_works_really) { int result; -# if __linux__ +# if __linux__ || __sun /* As recently as Linux kernel 2.6.32 (Dec 2009), several file systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT, but work if both times are either explicitly specified or UTIME_NOW. Work around it with a preparatory lstat prior to calling utimensat; fortunately, there is not much timing impact due to the extra syscall even on file systems where - UTIME_OMIT would have worked. FIXME: Simplify this in 2012, - when file system bugs are no longer common. */ + UTIME_OMIT would have worked. + + The same bug occurs in Solaris 11.1 (Apr 2013). + + FIXME: Simplify this for Linux in 2016 and for Solaris in + 2024, when file system bugs are no longer common. */ if (adjustment_needed == 2) { if (lstat (file, &st)) @@ -444,7 +475,7 @@ lutimens (char const *file, struct timespec const timespec[2]) /* Note that st is good, in case utimensat gives ENOSYS. */ adjustment_needed++; } -# endif /* __linux__ */ +# endif result = utimensat (AT_FDCWD, file, ts, AT_SYMLINK_NOFOLLOW); # ifdef __linux__ /* Work around a kernel bug: @@ -484,7 +515,7 @@ lutimens (char const *file, struct timespec const timespec[2]) #if HAVE_LUTIMES && !HAVE_UTIMENSAT { struct timeval timeval[2]; - struct timeval const *t; + struct timeval *t; int result; if (ts) { @@ -507,7 +538,7 @@ lutimens (char const *file, struct timespec const timespec[2]) if (!(adjustment_needed || REPLACE_FUNC_STAT_FILE) && lstat (file, &st)) return -1; if (!S_ISLNK (st.st_mode)) - return fdutimens (file, -1, ts); + return fdutimens (-1, file, ts); errno = ENOSYS; return -1; }