utimes.c

glibc 库, 不仅可以学习使用库函数,还可以学习函数的具体实现,是提高功力的好资料

/* Copyright (C) 1991-1995,1997,1999,2000,2006
	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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <sys/time.h>
#include <errno.h>
#include <stddef.h>
#include <hurd.h>

/* Change the access time of FILE to TVP[0] and
   the modification time of FILE to TVP[1].  */
int
__utimes (file, tvp)
     const char *file;
     const struct timeval tvp[2];
{
  union tv
  {
    struct timeval tv;
    time_value_t tvt;
  };
  const union tv *u = (const union tv *) tvp;
  union tv nulltv[2];
  error_t err;
  file_t port;

  if (tvp == NULL)
    {
      /* Setting the number of microseconds to `-1' tells the
         underlying filesystems to use the current time.  */
      nulltv[0].tvt.microseconds = nulltv[1].tvt.microseconds = -1;
      u = nulltv;
    }

  port = __file_name_lookup (file, 0, 0);
  if (port == MACH_PORT_NULL)
    return -1;
  err = __file_utimes (port, u[0].tvt, u[1].tvt);
  __mach_port_deallocate (__mach_task_self (), port);
  if (err)
    return __hurd_fail (err);
  return 0;
}
weak_alias (__utimes, utimes)