Exemplo n.º 1
0
int
fdutimens (int fd, char const *file, struct timespec const timespec[2])
{
    struct timespec adjusted_timespec[2];
    struct timespec *ts = timespec ? adjusted_timespec : NULL;
    int adjustment_needed = 0;
    struct stat st;

    if (ts)
    {
        adjusted_timespec[0] = timespec[0];
        adjusted_timespec[1] = timespec[1];
        adjustment_needed = validate_timespec (ts);
    }
    if (adjustment_needed < 0)
        return -1;

    /* 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 (fd < 0 && !file)
    {
        errno = EBADF;
        return -1;
    }

    /* 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

    /* POSIX 2008 added two interfaces to set file timestamps with
       nanosecond resolution; newer Linux implements both functions via
       a single syscall.  We provide a fallback for ENOSYS (for example,
       compiling against Linux 2.6.25 kernel headers and glibc 2.7, but
       running on Linux 2.6.18 kernel).  */
#if HAVE_UTIMENSAT || HAVE_FUTIMENS
    if (0 <= utimensat_works_really)
    {
        int result;
# if __linux__
        /* 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.  */
        if (adjustment_needed == 2)
        {
            if (fd < 0 ? stat (file, &st) : fstat (fd, &st))
                return -1;
            if (ts[0].tv_nsec == UTIME_OMIT)
                ts[0] = get_stat_atime (&st);
            else if (ts[1].tv_nsec == UTIME_OMIT)
                ts[1] = get_stat_mtime (&st);
            /* Note that st is good, in case utimensat gives ENOSYS.  */
            adjustment_needed++;
        }
# endif /* __linux__ */
# if HAVE_UTIMENSAT
        if (fd < 0)
        {
            result = utimensat (AT_FDCWD, file, ts, 0);
#  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 /* __linux__ */
            if (result == 0 || errno != ENOSYS)
            {
                utimensat_works_really = 1;
                return result;
            }
        }
# endif /* HAVE_UTIMENSAT */
# if HAVE_FUTIMENS
        if (0 <= fd)
        {
            result = futimens (fd, ts);
#  ifdef __linux__
            /* Work around the same bug as above.  */
            if (0 < result)
                errno = ENOSYS;
#  endif /* __linux__ */
            if (result == 0 || errno != ENOSYS)
            {
                utimensat_works_really = 1;
                return result;
            }
        }
# endif /* HAVE_FUTIMENS */
    }
    utimensat_works_really = -1;
    lutimensat_works_really = -1;
#endif /* HAVE_UTIMENSAT || HAVE_FUTIMENS */

    /* 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 (adjustment_needed || (REPLACE_FUNC_STAT_FILE && fd < 0))
    {
        if (adjustment_needed != 3
                && (fd < 0 ? stat (file, &st) : fstat (fd, &st)))
            return -1;
        if (ts && update_timespec (&st, &ts))
            return 0;
    }

    {
#if HAVE_FUTIMESAT || HAVE_WORKING_UTIMES
        struct timeval timeval[2];
        struct timeval *t;
        if (ts)
        {
            timeval[0].tv_sec = ts[0].tv_sec;
            timeval[0].tv_usec = ts[0].tv_nsec / 1000;
            timeval[1].tv_sec = ts[1].tv_sec;
            timeval[1].tv_usec = ts[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 && !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)
            {
#  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 */

        if (!file)
        {
#if ! ((HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG)          \
        || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
            errno = ENOSYS;
#endif
            return -1;
        }

#if HAVE_WORKING_UTIMES
        return utimes (file, t);
#else
        {
            struct utimbuf utimbuf;
            struct utimbuf *ut;
            if (ts)
            {
                utimbuf.actime = ts[0].tv_sec;
                utimbuf.modtime = ts[1].tv_sec;
                ut = &utimbuf;
            }
            else
                ut = NULL;

            return utime (file, ut);
        }
#endif /* !HAVE_WORKING_UTIMES */
    }
}
Exemplo n.º 2
0
/* Set the access and modification time stamps of FILE to be
   TIMESPEC[0] and TIMESPEC[1], respectively, without dereferencing
   symlinks.  Fail with ENOSYS if the platform does not support
   changing symlink timestamps, but FILE was a symlink.  */
int
lutimens (char const *file, struct timespec const timespec[2])
{
    struct timespec adjusted_timespec[2];
    struct timespec *ts = timespec ? adjusted_timespec : NULL;
    int adjustment_needed = 0;
    struct stat st;

    if (ts)
    {
        adjusted_timespec[0] = timespec[0];
        adjusted_timespec[1] = timespec[1];
        adjustment_needed = validate_timespec (ts);
    }
    if (adjustment_needed < 0)
        return -1;

    /* The Linux kernel did not support symlink timestamps until
       utimensat, in version 2.6.22, so we don't need to mimic
       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__
        /* 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.  */
        if (adjustment_needed == 2)
        {
            if (lstat (file, &st))
                return -1;
            if (ts[0].tv_nsec == UTIME_OMIT)
                ts[0] = get_stat_atime (&st);
            else if (ts[1].tv_nsec == UTIME_OMIT)
                ts[1] = get_stat_mtime (&st);
            /* Note that st is good, in case utimensat gives ENOSYS.  */
            adjustment_needed++;
        }
# endif /* __linux__ */
        result = utimensat (AT_FDCWD, file, ts, 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)
        {
            utimensat_works_really = 1;
            lutimensat_works_really = 1;
            return result;
        }
    }
    lutimensat_works_really = -1;
#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 (adjustment_needed || REPLACE_FUNC_STAT_FILE)
    {
        if (adjustment_needed != 3 && lstat (file, &st))
            return -1;
        if (ts && update_timespec (&st, &ts))
            return 0;
    }

    /* On Linux, lutimes is a thin wrapper around utimensat, so there is
       no point trying lutimes if utimensat failed with ENOSYS.  */
#if HAVE_LUTIMES && !HAVE_UTIMENSAT
    {
        struct timeval timeval[2];
        struct timeval *t;
        int result;
        if (ts)
        {
            timeval[0].tv_sec = ts[0].tv_sec;
            timeval[0].tv_usec = ts[0].tv_nsec / 1000;
            timeval[1].tv_sec = ts[1].tv_sec;
            timeval[1].tv_usec = ts[1].tv_nsec / 1000;
            t = timeval;
        }
        else
            t = NULL;

        result = lutimes (file, t);
        if (result == 0 || errno != ENOSYS)
            return result;
    }
#endif /* HAVE_LUTIMES && !HAVE_UTIMENSAT */

    /* Out of luck for symlinks, but we still handle regular files.  */
    if (!(adjustment_needed || REPLACE_FUNC_STAT_FILE) && lstat (file, &st))
        return -1;
    if (!S_ISLNK (st.st_mode))
        return fdutimens (-1, file, ts);
    errno = ENOSYS;
    return -1;
}
Exemplo n.º 3
0
int
fdutimens (int fd, char const *file, struct timespec const timespec[2])
{
  struct timespec adjusted_timespec[2];
  struct timespec *ts = timespec ? adjusted_timespec : NULL;
  int adjustment_needed = 0;
  struct stat st;

  if (ts)
    {
      adjusted_timespec[0] = timespec[0];
      adjusted_timespec[1] = timespec[1];
      adjustment_needed = validate_timespec (ts);
    }
  if (adjustment_needed < 0)
    return -1;

  /* 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 (fd < 0 && !file)
    {
      errno = EBADF;
      return -1;
    }

  /* Some Linux-based NFS clients are buggy, and mishandle timestamps
     of files in NFS file systems in some cases.  We have no
     configure-time test for this, but please see
     <https://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

  /* POSIX 2008 added two interfaces to set file timestamps with
     nanosecond resolution; newer Linux implements both functions via
     a single syscall.  We provide a fallback for ENOSYS (for example,
     compiling against Linux 2.6.25 kernel headers and glibc 2.7, but
     running on Linux 2.6.18 kernel).  */
#if HAVE_UTIMENSAT || HAVE_FUTIMENS
  if (0 <= utimensat_works_really)
    {
      int result;
# 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.

         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))
            return -1;
          if (ts[0].tv_nsec == UTIME_OMIT)
            ts[0] = get_stat_atime (&st);
          else if (ts[1].tv_nsec == UTIME_OMIT)
            ts[1] = get_stat_mtime (&st);
          /* Note that st is good, in case utimensat gives ENOSYS.  */
          adjustment_needed++;
        }
# endif
# if HAVE_UTIMENSAT
      if (fd < 0)
        {
          result = utimensat (AT_FDCWD, file, ts, 0);
#  ifdef __linux__
          /* Work around a kernel bug:
             https://bugzilla.redhat.com/show_bug.cgi?id=442352
             https://bugzilla.redhat.com/show_bug.cgi?id=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 /* __linux__ */
          if (result == 0 || errno != ENOSYS)
            {
              utimensat_works_really = 1;
              return result;
            }
        }
# endif /* HAVE_UTIMENSAT */
# if HAVE_FUTIMENS
      if (0 <= fd)
        {
          result = futimens (fd, ts);
#  ifdef __linux__
          /* Work around the same bug as above.  */
          if (0 < result)
            errno = ENOSYS;
#  endif /* __linux__ */
          if (result == 0 || errno != ENOSYS)
            {
              utimensat_works_really = 1;
              return result;
            }
        }
# endif /* HAVE_FUTIMENS */
    }
  utimensat_works_really = -1;
  lutimensat_works_really = -1;
#endif /* HAVE_UTIMENSAT || HAVE_FUTIMENS */

#ifdef USE_SETFILETIME
  /* On native Windows, use SetFileTime(). See
     <https://msdn.microsoft.com/en-us/library/ms724933.aspx>
     <https://msdn.microsoft.com/en-us/library/ms724284.aspx>  */
  if (0 <= fd)
    {
      HANDLE handle;
      FILETIME current_time;
      FILETIME last_access_time;
      FILETIME last_write_time;

      handle = (HANDLE) _get_osfhandle (fd);
      if (handle == INVALID_HANDLE_VALUE)
        {
          errno = EBADF;
          return -1;
        }

      if (ts == NULL || ts[0].tv_nsec == UTIME_NOW || ts[1].tv_nsec == UTIME_NOW)
        {
          /* GetSystemTimeAsFileTime
             <https://msdn.microsoft.com/en-us/library/ms724397.aspx>.
             It would be overkill to use
             GetSystemTimePreciseAsFileTime
             <https://msdn.microsoft.com/en-us/library/hh706895.aspx>.  */
          GetSystemTimeAsFileTime (&current_time);
        }

      if (ts == NULL || ts[0].tv_nsec == UTIME_NOW)
        {
          last_access_time = current_time;
        }
      else if (ts[0].tv_nsec == UTIME_OMIT)
        {
          last_access_time.dwLowDateTime = 0;
          last_access_time.dwHighDateTime = 0;
        }
      else
        {
          ULONGLONG time_since_16010101 =
            (ULONGLONG) ts[0].tv_sec * 10000000 + ts[0].tv_nsec / 100 + 116444736000000000LL;
          last_access_time.dwLowDateTime = (DWORD) time_since_16010101;
          last_access_time.dwHighDateTime = time_since_16010101 >> 32;
        }

      if (ts == NULL || ts[1].tv_nsec == UTIME_NOW)
        {
          last_write_time = current_time;
        }
      else if (ts[1].tv_nsec == UTIME_OMIT)
        {
          last_write_time.dwLowDateTime = 0;
          last_write_time.dwHighDateTime = 0;
        }
      else
        {
          ULONGLONG time_since_16010101 =
            (ULONGLONG) ts[1].tv_sec * 10000000 + ts[1].tv_nsec / 100 + 116444736000000000LL;
          last_write_time.dwLowDateTime = (DWORD) time_since_16010101;
          last_write_time.dwHighDateTime = time_since_16010101 >> 32;
        }

      if (SetFileTime (handle, NULL, &last_access_time, &last_write_time))
        return 0;
      else
        {
          DWORD sft_error = GetLastError ();
          #if 0
          fprintf (stderr, "fdutimens SetFileTime error 0x%x\n", (unsigned int) sft_error);
          #endif
          switch (sft_error)
            {
            case ERROR_ACCESS_DENIED: /* fd was opened without O_RDWR */
              errno = EACCES; /* not specified by POSIX */
              break;
            default:
              errno = EINVAL;
              break;
            }
          return -1;
        }
    }