source: buchla-68k/libcio/open.c@ f261cc8

/*
   =============================================================================
        open.c -- open a file for the Buchla 700 C I/O library functions
        Version 11 -- 1988-01-31 -- D.N. Lynx Crowe
   =============================================================================
*/

#include "ram.h"

static struct device condev  = { 2, 2, 1, 0, _nopo,   CON_DEV };
static struct device filedev = { 1, 1, 0, 1, _fileop,      -1 };

/*
   =============================================================================
        device table:  contains names and pointers to device control structures
   =============================================================================
*/

static struct devtabl devtabl[] = {

        { "con:", &condev  },   /* console device */
        { "CON:", &condev  },

        {      0, &filedev }    /* this MUST be the last entry */
};

/*
   =============================================================================
        open(name, flag, mode) -- Opens file 'name' with flags 'flag'
        and access mode 'mode'.  File will be ASCII unless opened with O_RAW.
        Returns a file descriptor (small positive integer) if successful, or
        FAILURE (-1) if an error occurred.
   =============================================================================
*/

int16_t open(int8_t *name, uint16_t flags)
{
        register struct devtabl *dp;
        register struct channel *chp;
        register struct device  *dev;
        int16_t fd;
        uint16_t mdmask;

        /* search for a free channel */

        for (chp = chantab, fd = 0 ; fd < MAXCHAN ; ++chp, ++fd)
                if (chp->c_close EQ _badfc)
                        goto fndchan;

        errno = EMFILE;         /* no channels available */
        return(FAILURE);

fndchan:        /* found a channel to use */

        for (dp = devtabl; dp->d_name; ++dp)     /* search for the device */
                if (strcmp(dp->d_name, name) EQ 0)
                        break;

        dev = dp->d_dev;
        mdmask = (flags & 3) + 1;

        if (mdmask & 1) {       /* see if device is readable */

                if ((chp->c_read = dev->d_read) EQ 0) {

                        errno = EACCES;         /* can't read */
                        return(FAILURE);
                }
        }

        if (mdmask & 2) {       /* see if device is writeable */

                if ((chp->c_write = dev->d_write) EQ 0) {

                        errno = EACCES;         /* can't write */
                        return(FAILURE);
                }
        }

        /* setup the channel table entries */

        chp->c_arg   = (io_arg)(int32_t)dp->d_dev->d_kind;
        chp->c_ioctl = dev->d_ioctl;
        chp->c_seek  = dev->d_seek;
        chp->c_close = _nopc;

        if ((*dev->d_open)(name, flags, chp, dp) < 0) { /* open */

                chp->c_close = _badfc;  /* couldn't open for some reason */
                return(FAILURE);
        }

        return(fd);
}

/*
   =============================================================================
        opena(name, flag, mode) -- Opens ASCII file 'name' with flags 'flags'
        Newline translation will be done.
        Returns a file descriptor (small positive integer) if successful, or
        FAILURE (-1) if an error occurred.
   =============================================================================
*/

int16_t opena(int8_t *name, uint16_t flags)
{
        return(open(name, flags));
}

/*
   =============================================================================
        openb(name, flag, mode) -- Opens binary file 'name' with flags 'flags'.
        No newline translation is done.
        Returns a file descriptor (small positive integer) if successful, or
        FAILURE (-1) if an error occurred.
   =============================================================================
*/

int16_t openb(int8_t *name, uint16_t flags)
{
        return(open(name, flags|O_RAW));
}

/*
   =============================================================================
        creat(name, mode) -- Creates file 'name'.
        The created file is initially open for writing only.  The file
        will be ASCII.
        Returns a file descriptor (small positive integer) if successful, or
        FAILURE (-1) if an error occurred.
   =============================================================================
*/

int16_t creat(int8_t *name)
{
        return(open(name, O_WRONLY|O_TRUNC|O_CREAT));
}

/*
   =============================================================================
        creata(name, mode) -- Creates ASCII file 'name'.
        The created file is initially open for writing only.
        Files created with creata() do newline translations.
        Returns a file descriptor (small positive integer) if successful, or
        FAILURE (-1) if an error occurred.
   =============================================================================
*/

int16_t creata(int8_t *name)
{
        return(open(name, O_WRONLY|O_TRUNC|O_CREAT));
}

/*
   =============================================================================
        creatb(name, mode) -- create binary file 'name'.
        The created file is initially open for writing only.
        Files created with creatb don't do newline translations.
        Returns a file descriptor (small positive integer) if successful, or
        FAILURE (-1) if an error occurred.
   =============================================================================
*/

int16_t creatb(int8_t *name)
{
        return(open(name, O_WRONLY|O_TRUNC|O_CREAT|O_RAW));
}

/*
   =============================================================================
        _fileop(name, flag, mode, chp, dp) -- Opens disk file 'name' with
        flags 'flag' in mode 'mode' with channel pointer 'chp' and
        device pointer 'dp'.  Returns SUCCESS (0) or FAILURE (-1).
   =============================================================================
*/

int16_t _fileop(int8_t *name, uint16_t flags, struct channel *chp, struct devtabl *dp)
{
        register struct fcb *fp;
        int8_t  tmpname[9], tmpext[4];

        (void)dp;

        /* search for an available fcb entry */

        for (fp = _fcbtab; fp < (_fcbtab + MAXDFILE); ++fp)
                if (fp->modefl EQ 0)
                        goto havefcb;

        errno = ENFILE;         /* no fcb space available for file */
        return (FAILURE);

havefcb:

        /* setup the initial fcb */

        if (_inifcb(fp, FilName(name, tmpname), FilExt(name, tmpext), flags)) {

                errno = EINVAL;         /* bad file name or flags */
                return(FAILURE);
        }

        if (_opfcb(fp))                 /* open the file */
                return(FAILURE);

        chp->c_arg   = fp;              /* allocate the channel */
        chp->c_close = _filecl;

        return(SUCCESS);
}