/*								-*-C-*-
 *	HUMBLE - Functions for hacking inferiors.
 */

#include "c-env.h"
#include "errno.h"
#include "sys/usysio.h"
#include "sys/usysig.h"
#include "sys/file.h"
#include "sysits.h"
#include "sys/humble.h"

#if !SYS_ITS
#error This is an ITS specific file!
#endif

/* Why the hell isn't there a .CALL version of this? */
static void uclose(ch)
  int ch;
{
#asm
	HRLZ 1,-1(17)
	LSH 1,5
	IOR 1,[.UCLOSE 0,]
	XCT 1
#endasm
}

/* The best source of unique sixbit words */
static int gensym()
{
#asm
	.GENSYM 1,
#endasm
}

/* Creates an inferior, returns an FD or -1 if failure */
int j_create()
{
    int fd, ufx, jname, val;

    USYS_BEG();

    if ((fd = _uiofd()) == -1 || !(ufx = _uiofx()))
	USYS_RETERR(EMFILE);

    _uiobsize[ufx] = 9;
    _uioflgs[ufx] |= _UIO_HANDPACK;	/* Block mode channel */

    do {
	jname = gensym();
	val = SYSCALL5("open", SC_IMC(_BIO), _uioch[ufx],
		       SC_SIX("usr"), SC_IMM(0), &jname);
    } while (val == _ENSMD);	/* Keep trying names until unique */

    if (val) USYS_RETERR(ENOENT);

    _openufx(ufx, (O_WRONLY | O_CREAT | O_TRUNC | O_BSIZE_9));
    _uioufx[fd] = ufx;
    USYS_RET(fd);
}

/* Kills the specified inferior.  Just like close() except it actually
 * destroys the job.  Can only be applied to the last open FD.
 */
int j_kill(fd)
  int fd;
{
    int ufx, val;

    USYS_BEG();

    if (fd < 0 || fd >= OPEN_MAX
	  || !(ufx = _uioufx[fd])
	  || _uiotype[ufx] != _DVUSR	/* Better be a job */
	  || _uionopen[ufx] != 1)	/* This better be the only FD */
	USYS_RETERR(EBADF);

    uclose(_uioch[ufx]);	/* Kill it */
    _uiozcnt[ufx] = 0;		/* Channel now closed, so forget these */

    val = close(fd);		/* Shut down rest of I/O system */
    USYS_RET(val);		/* Pass on any errors from close() */
}

/* Devour the TTY.  Always returns 0.  Can't possibly fail! */
/* (I suppose there should be a .CALL version of this, but...) */
int j_dtty()
{
#asm
	.DTTY
	SETZI 1,
#endasm
}

/* Allow an inferior to make use of the TTY.  Returns 0 if it wins, -1
 * if failure.
 * Possible errors:
 *  - Bad FD.
 *  - Job isn't an inferior.
 */
int j_atty(fd)
  int fd;
{
    int ufx;

    USYS_BEG();

    if (fd < 0 || fd >= OPEN_MAX
	  || !(ufx = _uioufx[fd])
	  || _uiotype[ufx] != _DVUSR)
	USYS_RETERR(EBADF);

    if (SYSCALL1("atty", _uiodnum[ufx]))
	USYS_RETERR(EBADF);

    USYS_RET(0);
}

/* Read a user variable.  Returns 0 if it wins, -1 if failure.
 * VAR is a user variable specifier.  LOC is where to store the result.
 * Possible errors:
 *  - Bad FD.
 *  - No such user variable.
 */
int j_vread(fd, var, loc)
  int fd, var, *loc;
{
    int ufx;

    USYS_BEG();

    if (fd < 0 || fd >= OPEN_MAX
	  || !(ufx = _uioufx[fd])
	  || _uiotype[ufx] != _DVUSR)
	USYS_RETERR(EBADF);

    if (SYSCALL3("usrvar", _uiodnum[ufx], &var, SC_VAL(loc)))
	USYS_RETERR(EINVAL);

    USYS_RET(0);
}

/* Write a user variable.  Returns 0 if it wins, -1 if failure.
 * VAR is a user variable specifier.  VAL is the new value.
 * Possible errors:
 *  - Bad FD.
 *  - No such user variable.
 *  - Can't write into this job.
 */
int j_vwrite(fd, var, val)
  int fd, var, val;
{
    int ufx;

    USYS_BEG();

    if (fd < 0 || fd >= OPEN_MAX
	  || !(ufx = _uioufx[fd])
	  || _uiotype[ufx] != _DVUSR)
	USYS_RETERR(EBADF);

    if (SYSCALL3("usrvar", _uiodnum[ufx], &var, &val))
	USYS_RETERR(EINVAL);

    USYS_RET(0);
}

/* Recover file position for file UFX after LOAD or PDUMP system call */
static void correct_pos(ufx)
  int ufx;
{
    int syspos;

    if (SYSCALL2("rfpntr", _uioch[ufx], SC_VAL(&syspos))) return;
    _uiopos[ufx] = ((_uioflgs[ufx] & _UIO_HANDPACK) ?
		    (syspos * _uiobword[ufx]) : syspos);
    _uiozcnt[ufx] = 0;
    _uiocnt[ufx] = 0;
    _uioeof[ufx] = 0;
    return;
}

/* Writes a PDUMP file for the job on the freshly opened file.
 * Returns 0 if we win and -1 if we lose.
 * Possible errors:
 *  - Bad FD for job.
 *  - File FD isn't open to DSK.
 *  - DSK or directory full, etc.
 */
int j_dump(job_fd, file_fd)
  int job_fd, file_fd;
{
    int job_ufx, file_ufx, state = 0;

    USYS_BEG();

    if (job_fd < 0 || job_fd >= OPEN_MAX
	    || !(job_ufx = _uioufx[job_fd])
	    || _uiotype[job_ufx] != _DVUSR
	    || file_fd < 0 || file_fd >= OPEN_MAX
	    || !(file_ufx = _uioufx[file_fd]))
	USYS_RETERR(EBADF);

    if (SYSCALL3("pdump", _uiodnum[job_ufx], _uioch[file_ufx], &state))
	USYS_RETERR(EIO);

    correct_pos(file_ufx);

    USYS_RET(0);
}

/* Loads a PDUMP or SBLK file into the job from the freshly opened file.
 * Returns 0 if we win and -1 if we lose.
 * Possible errors:
 *  - Bad FD for job.
 *  - File FD isn't open to DSK.
 *  - File is in the wrong format.
 */
int j_load(job_fd, file_fd)
  int job_fd, file_fd;
{
    int job_ufx, file_ufx;

    USYS_BEG();

    if (job_fd < 0 || job_fd >= OPEN_MAX
	    || !(job_ufx = _uioufx[job_fd])
	    || _uiotype[job_ufx] != _DVUSR
	    || file_fd < 0 || file_fd >= OPEN_MAX
	    || !(file_ufx = _uioufx[file_fd]))
	USYS_RETERR(EBADF);

    if (SYSCALL2("load", _uiodnum[job_ufx], _uioch[file_ufx]))
	USYS_RETERR(EIO);

    correct_pos(file_ufx);

    USYS_RET(0);
}