open.c

C标准库源代码

#pragma data_seg()

/* Mac definitions for ioDenyModes */

#define MAC_PERMRD 0x0001
#define MAC_PERMWR 0x0002
#define MAC_DENYRD 0x0010
#define MAC_DENYWR 0x0020


/***
*int _open(path, flag, pmode) - open or create a file
*
*Purpose:
*       Opens the file and prepares for subsequent reading or writing.
*       the flag argument specifies how to open the file:
*         _O_APPEND -   reposition file ptr to end before every write
*         _O_BINARY -   open in binary mode
*         _O_CREAT -    create a new file* no effect if file already exists
*         _O_EXCL -     return error if file exists, only use with O_CREAT
*         _O_RDONLY -   open for reading only
*         _O_RDWR -     open for reading and writing
*         _O_TEXT -     open in text mode
*         _O_TRUNC -    open and truncate to 0 length (must have write permission)
*         _O_WRONLY -   open for writing only
*       exactly one of _O_RDONLY, _O_WRONLY, _O_RDWR must be given
*
*       The pmode argument is only required when _O_CREAT is specified.  Its
*       flag settings:
*         _S_IWRITE -   writing permitted
*         _S_IREAD -    reading permitted
*         _S_IREAD | _S_IWRITE - both reading and writing permitted
*       The current file-permission masks is applied to pmode before
*       setting the permission (see umask).
*
*       Note, the _creat() function also uses this function but setting up the
*       correct arguments and calling _open().
*
*Entry:
*       char *path - file name
*       int flag - flags for _open()
*       int pmode - permission mode for new files
*
*Exit:
*       returns file handle of open file if successful
*       returns -1 (and sets errno) if fails
*
*Exceptions:
*
*******************************************************************************/

int __cdecl _open (
        const char *path,
        int oflag,
        ...
        )
{
        va_list ap;

        va_start(ap, oflag);
        /* default sharing mode is DENY NONE */
        return _sopen(path, oflag, _SH_DENYNO, va_arg(ap, int));
}

/***
*void __mopen(stpath, fh, ioPermssn, ioDenyModes) - MAC open a file with sharing
*
*Purpose:
*       Worker routine to open a file on the MAC.  It only opens the file.
*  If local open fails it will try AppleShare oepn.
*
*Entry:
*       char *stpath -  file to open (Pascal string)
*       int fh - file handle to use
*       int ioPermssn - persmission modes flags
*       int ioDenyModes -       Deny mode flags
*
*Exit:
*       returns TRUE if successful and sets errno & _osfhnd[fh] &
*                       _osfile[fh] if successful
*
*Exceptions:
*
*******************************************************************************/

int __cdecl __mopen (
        char *stpath,
        int fh,
        int ioPermssn,
        int ioDenyModes
        )
{
        HParamBlockRec parm;
        OSErr osErr;
        char sz[256];
        char buf[10];
        char *pch;

        //if starts with full path, test the availability of the volume
        memcpy(sz, stpath, (*stpath+1));
        _p2cstr(sz);

        if (*sz != ':' && (pch = strchr(sz, ':')) != NULL)
        {
                *(pch+1) = '\0';
                _c2pstr(sz);
                memset(&parm, 0, sizeof(HParamBlockRec));
                memset(buf, 0, 10);
                parm.ioParam.ioNamePtr = sz;
                parm.ioParam.ioBuffer = buf;
                parm.ioParam.ioReqCount = 6;
                osErr = PBHGetVolParmsSync(&parm);

                if (!osErr)
                {
                        if (!(buf[4]&0x8000))
                        {
                                parm.ioParam.ioNamePtr = stpath;
                                parm.ioParam.ioVRefNum = 0;
                                goto local;
                        }
                }
                else
                {
                        _dosmaperr(osErr);
                        return osErr;
                }
        }

        /* try to open the file using Appleshare calls*/
        parm.ioParam.ioNamePtr = stpath;
        parm.ioParam.ioVRefNum = 0;
        parm.accessParam.ioDenyModes = (unsigned char)ioDenyModes;
        _osperm[fh] = (unsigned char)ioDenyModes;
        parm.fileParam.ioDirID = 0;
        parm.ioParam.ioMisc = NULL;
        osErr = PBHOpenDenySync(&parm);

        if (osErr == paramErr)
        {
local:
                /* Try local open */
                parm.ioParam.ioPermssn = ioPermssn;
                _osperm[fh] = (unsigned char)ioPermssn;
                osErr = PBHOpenDFSync(&parm);
        }

        if (!osErr)
        {
                _osfile[fh] |= FOPEN;
                _osfhnd[fh] = parm.ioParam.ioRefNum;
        }
        else
        {
                _dosmaperr(osErr);
        }

        return osErr;
}

/***
*int _sopen(path, oflag, shflag, pmode) - open a file with sharing
*
*Purpose:
*       Opens the file with possible file sharing.
*       shflag defines the sharing flags:
*         _SH_DENYRW -  deny read and write access to the file
*         _SH_DENYNO -  permit read and write access
*
*       Other flags are the same as _open().
*
*       SOPEN is the routine used when file sharing is desired.
*
*Entry:
*       char *path - file to open (C string)
*       int oflag -     open flag
*       int shflag -    sharing flag
*       int pmode -     permission mode (needed only when creating file)
*
*Exit:
*       returns file handle for the opened file
*       returns -1 and sets errno if fails.
*
*Exceptions:
*
*******************************************************************************/

int _cdecl _sopen (
        const char *path,
        int oflag,
        int shflag,
        ...
        )
{

        int fh;         /* handle of opened file */
        OSErr osErr = 0;
        unsigned char ioPermssn;
        short int ioDenyModes;
        ParamBlockRec parm;
        int pmode;
        va_list ap;                     /* variable argument (pmode) */
        char lpath[256];

        if (!*path)
        {
                errno = ENOENT;
                return -1;
        }

        strcpy(lpath,path);
        _c2pstr(lpath);

        /* get a file handle*/
        for (fh = 0; fh <_nfile; fh++)
        {
                if (!(_osfile[fh] & FOPEN))
                {
                        break;
                }
        }

        if (fh >= _nfile)
        {
                errno = EMFILE;
                _macerrno = 0;
                return -1;
        }

        _osfile[fh] = 0;
                _osfileflags[fh] = 0;

        /* figure out binary/text mode */

        switch (oflag  & (_O_BINARY | _O_TEXT))
        {
                case _O_BINARY:
                        break;

                case _O_TEXT:
                        _osfile[fh] = (unsigned char)FTEXT;
                        break;

                case _O_TEXT | _O_BINARY:
                        errno = EINVAL;
                        return -1;

                default:
                        if (_fmode != _O_BINARY)
                        {
                                _osfile[fh] = (unsigned char)FTEXT;
                        }
                        break;
        }

        /* figure out read/write modes */

        switch (oflag & (_O_RDWR | _O_RDONLY | _O_WRONLY))
        {
                case _O_RDONLY:
                        ioPermssn = fsRdPerm;
                        _osfile[fh] |= FRDONLY;
                        if (oflag & _O_TRUNC)
                        {
                                errno = EINVAL;
                                return -1;
                        }
                        ioDenyModes = MAC_PERMRD;
                        break;

                case _O_WRONLY:
                        ioPermssn = fsRdWrShPerm;
                        _osfile[fh] |= FWRONLY;
                        ioDenyModes = MAC_PERMWR;
                        break;

                case _O_RDWR:
                        ioPermssn  = fsRdWrPerm;
                        ioDenyModes = MAC_PERMRD | MAC_PERMWR;
                        break;

                default:
                        errno = EINVAL;
                        return -1;
        }

        switch (shflag)
        {
                case _SH_DENYRD:
                        ioDenyModes |= MAC_DENYRD;
                        break;

                case _SH_DENYWR:
                        ioDenyModes |= MAC_DENYWR;
                        break;

                case _SH_DENYRW:
                        ioDenyModes |= MAC_DENYRD | MAC_DENYWR;
                        break;

                case _SH_DENYNO:
                        if (ioPermssn == fsRdWrPerm)
                        {
                                ioPermssn = fsRdWrShPerm;
                        }
                        break;

                default:
                        errno = EINVAL;
                        return -1;
        }

        if (!(oflag & _O_CREAT && oflag & _O_EXCL))
        {
                /* try to open the file */
                if (!__mopen(lpath, fh, ioPermssn, ioDenyModes))
                {
                        oflag &= ~_O_CREAT;     /*file open - no need to create*/
                }
        }

        /* Didn't work try creating the file if requested */
        if (oflag & _O_CREAT)
        {
                /* reset errno from mopen, since we can try create*/
                errno = 0;
                va_start(ap, shflag);
                pmode = va_arg(ap, int);
                pmode &= ~_umaskval;
                if (!(pmode & (_S_IREAD | _S_IWRITE)))
                {
                        errno = EINVAL;
                        return -1;
                }
                parm.fileParam.ioNamePtr = lpath;
                parm.fileParam.ioVRefNum = 0;
                osErr = PBCreateSync(&parm);
                if (!osErr)
                {
                        parm.fileParam.ioFDirIndex = 0;
                        PBGetFInfoSync(&parm);
                        parm.fileParam.ioFlFndrInfo.fdType = (_osfile[fh] & FTEXT ? 'TEXT' : '    ');
                        parm.fileParam.ioFlFndrInfo.fdCreator = '    ';
                        PBSetFInfoSync(&parm);
                }
                else
                {
                        if (osErr == dupFNErr && oflag & _O_EXCL)
                        {
                                errno = EEXIST; /*special case normally returns EACCES*/
                                _macerrno = osErr;
                        }
                        else
                        {
                                _dosmaperr(osErr);
                        }
                        return -1;
                }
                if (osErr = __mopen(lpath, fh, ioPermssn, ioDenyModes))
                {
                        _dosmaperr(osErr);
                        return -1;
                }
                else if (!(pmode & _S_IWRITE))
                {
                        PBSetFLockSync(&parm);
                }
        }
        if (!(_osfile[fh] & FOPEN))
        {
                goto ErrExit;
        }

        parm.ioParam.ioRefNum = _osfhnd[fh];

        /* Truncate file */
        if (oflag & _O_TRUNC)
        {
                parm.ioParam.ioMisc = 0;
                osErr = PBSetEOFSync(&parm);
                if (osErr)
                {
                        _dosmaperr(osErr);
                        goto ErrExit;
                }
        }

        /* get vol reference */
        parm.volumeParam.ioVolIndex = -1;
        parm.ioParam.ioNamePtr = lpath;
        parm.ioParam.ioVRefNum = 0;
        osErr = PBGetVInfoSync(&parm);
        if (osErr)
        {
                _dosmaperr(osErr);
                goto ErrExit;
        }
        _osVRefNum[fh] = parm.volumeParam.ioVRefNum;

        if (oflag & _O_APPEND)
        {
                _osfile[fh] |= FAPPEND;
        }

        if (oflag & _O_TEMPORARY)
        {
                _osfileflags[fh] |= FTEMP;
        }
        return fh;                      /* return handle */


ErrExit:
        if (_osfile[fh] & FOPEN)
        {
                PBCloseSync(&parm);
                _osfile[fh] = 0;
        }
        return -1;
}


#endif  /* _MAC */