fstat.c

C语言库函数的原型,有用的拿去

/***
*fstat.c - return file status info
*
*       Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*       defines _fstat32() - return file status info
*
*******************************************************************************/

#include <cruntime.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdlib.h>
#include <msdos.h>
#include <io.h>
#include <internal.h>
#include <stddef.h>
#include <oscalls.h>
#include <stdio.h>
#include <mtdll.h>
#include <time.h>

#define IO_DEVNBR   0x3f

/***
*int _fstat32(fildes, buf) - fills supplied buffer with status info
*
*Purpose:
*       Fills the supplied buffer with status information on the
*       file represented by the specified file designator.
*       WARNING: the dev/rdev fields are zero for files.  This is
*       incompatible with DOS 3 version of this routine.
*
*       Note: We cannot directly use the file time stamps returned in the
*       BY_HANDLE_FILE_INFORMATION structure. The values are supposedly in
*       system time and system time is ambiguously defined (it is UTC for
*       Windows NT, local time for Win32S and probably local time for
*       Win32C). Therefore, these values must be converted to local time
*       before than can be used.
*
*Entry:
*       int fildes   - file descriptor
*       struct stat *buf - buffer to store result in
*
*Exit:
*       fills in buffer pointed to by buf
*       returns 0 if successful
*       returns -1 and sets errno if unsuccessful
*
*Exceptions:
*
*******************************************************************************/

#ifdef _USE_INT64

int __cdecl _fstat32i64 (
        int fildes,
        struct _stat32i64 *buf
        )

#else  /* _USE_INT64 */

int __cdecl _fstat32 (
        int fildes,
        struct _stat32 *buf
        )

#endif  /* _USE_INT64 */
{
        int isdev;          /* 0 for a file, 1 for a device */
        int retval = 0;     /* assume good return */
        BY_HANDLE_FILE_INFORMATION bhfi;
        FILETIME LocalFTime;
        SYSTEMTIME SystemTime;

        _VALIDATE_CLEAR_OSSERR_RETURN( (buf != NULL), EINVAL, -1 );
        memset(buf, 0, sizeof(*buf));

        _CHECK_FH_CLEAR_OSSERR_RETURN( fildes, EBADF, -1 );
        _VALIDATE_CLEAR_OSSERR_RETURN((fildes >= 0 && (unsigned)fildes < (unsigned)_nhandle), EBADF, -1);
        _VALIDATE_CLEAR_OSSERR_RETURN((_osfile(fildes) & FOPEN), EBADF, -1);

        /* Lock the file */
        _lock_fh(fildes);
        __try {
            if ( !(_osfile(fildes) & FOPEN) ) {
                errno = EBADF;
                retval = -1;
                _ASSERTE(("Invalid file descriptor. File possibly closed by a different thread",0));
                goto done;
            }

        /* Find out what kind of handle underlies filedes
         */
        isdev = GetFileType((HANDLE)_osfhnd(fildes)) & ~FILE_TYPE_REMOTE;

        if ( isdev != FILE_TYPE_DISK ) {

            /* not a disk file. probably a device or pipe
             */
            if ( (isdev == FILE_TYPE_CHAR) || (isdev == FILE_TYPE_PIPE) ) {
                /* treat pipes and devices similarly. no further info is
                 * available from any API, so set the fields as reasonably
                 * as possible and return.
                 */
                if ( isdev == FILE_TYPE_CHAR )
                    buf->st_mode = _S_IFCHR;
                else
                    buf->st_mode = _S_IFIFO;

                buf->st_rdev = buf->st_dev = (_dev_t)fildes;
                buf->st_nlink = 1;
                buf->st_uid = buf->st_gid = buf->st_ino = 0;
                buf->st_atime = buf->st_mtime = buf->st_ctime = 0;
                if ( isdev == FILE_TYPE_CHAR ) {
#ifdef _USE_INT64
                    buf->st_size = 0i64;
#else  /* _USE_INT64 */
                    buf->st_size = 0;
#endif  /* _USE_INT64 */
                }
                else {
                    unsigned long ulAvail;
                    int rc;
                    rc = PeekNamedPipe((HANDLE)_osfhnd(fildes),
                                       NULL,
                                       0,
                                       NULL,
                                       &ulAvail,
                                       NULL);

                    if (rc) {
                        buf->st_size = (_off_t)ulAvail;
                    }
                    else {
                        buf->st_size = (_off_t)0;
                    }
                }

                goto done;
            }
            else if ( isdev == FILE_TYPE_UNKNOWN ) {
                errno = EBADF;
                retval = -1;
                goto done;      /* join common return code */
            }
            else {
                /* according to the documentation, this cannot happen, but
                 * play it safe anyway.
                 */
                _dosmaperr(GetLastError());
                retval = -1;
                goto done;
            }
        }


        /* set the common fields
         */
        buf->st_ino = buf->st_uid = buf->st_gid = buf->st_mode = 0;
        buf->st_nlink = 1;

        /* use the file handle to get all the info about the file
         */
        if ( !GetFileInformationByHandle((HANDLE)_osfhnd(fildes), &bhfi) ) {
            _dosmaperr(GetLastError());
            retval = -1;
            goto done;
        }

        if ( bhfi.dwFileAttributes & FILE_ATTRIBUTE_READONLY )
            buf->st_mode |= (_S_IREAD + (_S_IREAD >> 3) + (_S_IREAD >> 6));
        else
            buf->st_mode |= ((_S_IREAD|_S_IWRITE) + ((_S_IREAD|_S_IWRITE) >> 3)
              + ((_S_IREAD|_S_IWRITE) >> 6));

        /* set file date fields
         */
        if ( bhfi.ftLastWriteTime.dwLowDateTime ||
             bhfi.ftLastWriteTime.dwHighDateTime )
        {

            if ( !FileTimeToLocalFileTime( &(bhfi.ftLastWriteTime), &LocalFTime )
                 || !FileTimeToSystemTime( &LocalFTime, &SystemTime ) )
            {
                retval = -1;
                goto done;
            }

            buf->st_mtime = __loctotime32_t(SystemTime.wYear,
                                            SystemTime.wMonth,
                                            SystemTime.wDay,
                                            SystemTime.wHour,
                                            SystemTime.wMinute,
                                            SystemTime.wSecond,
                                            -1);
        } else
            buf->st_mtime = 0 ;

        if ( bhfi.ftLastAccessTime.dwLowDateTime ||
             bhfi.ftLastAccessTime.dwHighDateTime )
        {

            if ( !FileTimeToLocalFileTime( &(bhfi.ftLastAccessTime),
                                           &LocalFTime ) ||
                 !FileTimeToSystemTime( &LocalFTime, &SystemTime ) )
            {
                retval = -1;
                goto done;
            }

            buf->st_atime = __loctotime32_t(SystemTime.wYear,
                                            SystemTime.wMonth,
                                            SystemTime.wDay,
                                            SystemTime.wHour,
                                            SystemTime.wMinute,
                                            SystemTime.wSecond,
                                            -1);
        }
        else
            buf->st_atime = buf->st_mtime;

        if ( bhfi.ftCreationTime.dwLowDateTime ||
             bhfi.ftCreationTime.dwHighDateTime )
        {

            if ( !FileTimeToLocalFileTime( &(bhfi.ftCreationTime),
                                           &LocalFTime ) ||
                 !FileTimeToSystemTime( &LocalFTime, &SystemTime ) )
            {
                retval = -1;
                goto done;
            }

            buf->st_ctime = __loctotime32_t(SystemTime.wYear,
                                            SystemTime.wMonth,
                                            SystemTime.wDay,
                                            SystemTime.wHour,
                                            SystemTime.wMinute,
                                            SystemTime.wSecond,
                                            -1);
        }
        else
            buf->st_ctime = buf->st_mtime;

#ifdef _USE_INT64
        buf->st_size = ((__int64)(bhfi.nFileSizeHigh)) * (0x100000000i64) +
                       (__int64)(bhfi.nFileSizeLow);
#else  /* _USE_INT64 */
        buf->st_size = bhfi.nFileSizeLow;
#endif  /* _USE_INT64 */

        buf->st_mode |= _S_IFREG;

        /* On DOS, this field contains the drive number, but
         * the drive number is not available on this platform.
         * Also, for UNC network names, there is no drive number.
         */
        buf->st_rdev = buf->st_dev = 0;

/* Common return code */

done:
        ; }
        __finally {
            _unlock_fh(fildes);
        }

        return(retval);
}