/*
 **********************************************************************
 *
 *  Component:	RDB servers
 *  Module:	servbkpt.c
 *
 *  Synopsis:	Management of breakpoints
 *
 * $Id$
 *
 **********************************************************************
 */

#include <sys/errno.h>
#include <assert.h>   
#include <rdbg/rdbg.h>
#include <rdbg/servrpc.h>

/*----- Macros -----*/

#define BKPT0(plst)	((BASE_BREAK*)(plst)->break_list)
#define BKPT_INCR	5	/* how many bkpt slots alloc at a time */

#define BKPT_OVER(plst,idx,addr,size) \
    ((plst)->break_list[idx].ee_loc + BREAK_SIZE > (UINT32) (addr) \
    &&  (plst)->break_list[idx].ee_loc < (UINT32) (addr) + (size))

#define BKPT_SLOTS \
	(sizeof ((xdr_break*) 0)->thread_list / \
	 sizeof ((xdr_break*) 0)->thread_list [0])


    /*
     *  BreakAlloc - alloc a breakpoint entry.
     *
     *  This is a generic routine to insert an entry in the
     *  breakpoint list. It returns the number of entry just
     *  created. It returns -1 if failed.
     */

    static int
BreakAlloc (PID_LIST* plst, Boolean normal)
{
    int		idx, len;
    xdr_break*	blst;

    if (!normal) {		/* want 0 entry */
	if (plst->break_list) {
	    return(0);		/* already there */
	}
	idx = 1;		/* force alloc below */
    } else {
	for (idx = 1; idx < (int)plst->break_alloc; idx++) {
	    if (plst->break_list[idx].type == BRKT_NONE) {
		    /* got a free one */
		memset(&plst->break_list[idx], 0, sizeof(xdr_break));
		return(idx);		/* found one */
	    }
	}
    }
	/* idx is the requested entry */

    if (idx >= (int)plst->break_alloc) { /* need more space */
	len = plst->break_alloc + BKPT_INCR;
	blst = (xdr_break*)Realloc(plst->break_list, len*sizeof(xdr_break));
	if (!blst) {
	    return(-1);		/* failed, no space */
	}
	plst->break_alloc = len;	/* got more */
	plst->break_list = blst;

	    /* Clear new space */
	memset(blst + len - BKPT_INCR, 0, BKPT_INCR * sizeof(xdr_break));
	idx = len - BKPT_INCR;		/* next available */
	if (!idx) {
	    idx = 1;			/* for normal cases */
	}
    }
    return(normal ? idx : 0);	/* return it */
}

    /*
     *  BreakSet - set a breakpoint in process
     *
     *  Returns the number or -1/errno.
     */

#ifdef DDEBUG
static const char* BreakTypes[] = {
    "NONE",   "INSTR", "READ",    "WRITE",
    "ACCESS", "EXEC",  "OS_CALL", "OS_SWITCH",
    "STEPEMUL"
};

#define BN_MAX		(sizeof BreakTypes / sizeof BreakTypes[0])
#define BREAK_NAME(t)	((unsigned) (t) < BN_MAX ? BreakTypes[t] : "???")
#endif

    int
BreakSet (PID_LIST* plst, int conn_idx, xdr_break* bkpt)
{
    int pid = plst->pid;
    int type = bkpt->type;
    void* addr = (void *) bkpt->ee_loc;
    int idx;
    int data;
    
    DPRINTF(("BreakSet: type %d (%s) at 0x%x th %d ee_type %d len %d "
	"pass %d curr %d list %d %d %d %d\n", type, BREAK_NAME(type),
	(int) addr,
	bkpt->thread_spec, bkpt->ee_type, bkpt->length, bkpt->pass_count,
	bkpt->curr_pass, bkpt->thread_list [0], bkpt->thread_list [1],
	bkpt->thread_list [2], bkpt->thread_list [3]));

    idx = BreakAlloc(plst, True); /* get entry */
    if (idx < 0) {		/* no memory */
        setErrno(ENOMEM);	/* set for safety */
	return -1;		/* return the error */
    }

    data = TgtPtrace(RPT_PEEKTEXT, pid, addr, 0, NULL); /* current */
    if (getErrno()) {
      return -1;		/* failed, return the error */
    }
    if (IS_BREAK(data)) {	/* There is already a break here */
      DPRINTF(("BreakSet: already have soft bkpt at %x\n", addr));
      if (type == BRKT_STEPEMUL) {
	++BKPT0 (plst)->pad1;
	return 1;	/* Any non-error value is OK */
      }
      setErrno(EBUSY);
      return -1;
    }

    TgtPtrace(RPT_POKETEXT, pid, addr, SET_BREAK(data), NULL);

    if (getErrno()) {
      return -1;
    }

    plst->break_list[idx] = *bkpt;
    plst->break_list[idx].ee_type = data; /* saved data */
	
    /* Inform other owners */
    if (type != BRKT_STEPEMUL) {
	TgtNotifyAll (plst - pid_list, BMSG_BREAK, 1 /*added*/, idx,
	    conn_idx, False);
    } else {
	++BKPT0 (plst)->pad1;
    }
	/* Return the number */
    setErrno(0);		/* Just in case */
    return idx;
}

    int
BreakSetAt (PID_LIST* plst, int conn_idx, unsigned long addr, break_type type)
{
    xdr_break xb;

    memset (&xb, 0, sizeof xb);
    xb.type = type;
    xb.ee_loc = addr;
    return BreakSet (plst, conn_idx, &xb);
}

/*----- Find a breakpoint by address -----*/

    int
BreakGetIndex(PID_LIST* plst, void* addr)
{
    int idx;
    int data = -1;

    if (!plst->break_alloc) {
        setErrno(EFAULT);
	return -1;
    }
    for (idx = 1; idx < (int)plst->break_alloc; idx++) {
	if ((u_long) addr == plst->break_list [idx].ee_loc) {
	    data = idx;
	    break;
        }              
    }
    return data;
}

/*----- Getting information about breakpoint -----*/

    /*
     *	If data > 0, fill "bkpt" with information about breakpoint
     *  and return the number of the next one.
     *  If data == 0, return the count of breakpoints.
     */

    int
BreakGet (const PID_LIST* plst, int data, xdr_break* bkpt)
{
    int idx;

    if (!data) {		/* just count them */
	for (idx = 1; idx < (int)plst->break_alloc; idx++) {
	    if (plst->break_list[idx].type != BRKT_NONE) {
		data++;
	    }
	}
	return data;	/* count */
    }
    if ((unsigned) data >= plst->break_alloc) {
	    /* out of range */
        setErrno(EFAULT);		/* closest match */
	return -1;
    }
	/* get it and say which is next */
    *bkpt = plst->break_list[data];
    for (idx = (int)data+1; idx < (int)plst->break_alloc; idx++) {
	if (plst->break_list[idx].type != BRKT_NONE) {
	    return idx;
	}
    }
    return 0;		/* otherwise returns 0 for no more */
}

/*----- Clearing bkpts -----*/

    /*
     *	BreakClear - clear one (if data != 0) or all breakpoints
     *  (if data == 0). Return the number of bkpts cleared.
     *  If (data == -1), remove step-emulation breakpoints.
     */

    int
BreakClear (PID_LIST* plst, int conn_idx, int data)
{
    int pid_idx = plst - pid_list;
    int idx;
    int cleared = 0;
    int clearStepEmul = 0;
    int terminated = PROC_TERMINATED (plst);
    int stepEmulCount = 0;

	/* break handle in data */
    if (!plst->break_alloc) {		/* there are no breaks */
	DPRINTF (("BreakClear: no bkpts defined.\n"));
	setErrno(EFAULT);		/* closest match */
	return -1;		/* return error */
    }
    if (!data) {				/* clear all */
	idx = 1;
	data = plst->break_alloc-1;

	    /* Inform other owners */
	DPRINTF (("BreakClear: clearing all bkpts.\n"));
	TgtNotifyAll (pid_idx, BMSG_BREAK, 0 /*clr*/, 0, conn_idx, False);

    } else if (data == -1) {		/* clear all step-emul bkpts */
	DPRINTF(("BreakClear: removing %d step-emul bkpts\n",
	    BKPT0 (plst)->pad1));

	stepEmulCount = BKPT0 (plst)->pad1;
	BKPT0 (plst)->pad1 = 0;

	clearStepEmul = 1;
	idx = 1;
	data = plst->break_alloc-1;
    } else if ((unsigned) data >= plst->break_alloc
	   ||  plst->break_list[data].type == BRKT_NONE) {

	    /* out of range */
	DPRINTF (("BreakClear: invalid bkpt %d\n", data));
	setErrno(EFAULT);		/* closest match */
	return -1;			/* return error */
    } else {
	idx = data;
	    /* Inform other owners */
	TgtNotifyAll (pid_idx, BMSG_BREAK, 0 /*clr*/, idx, conn_idx, False);
	DPRINTF (("BreakClear: clearing bkpt %d\n", data));
    }

    for (; idx <= data; idx++) {	/* clear each one */
	int type = plst->break_list[idx].type;

	if (clearStepEmul && type != BRKT_STEPEMUL) continue;

	if (type == BRKT_INSTR || (clearStepEmul && type == BRKT_STEPEMUL)) {
		/* just patch back */
	    char* addr = (char *)plst->break_list[idx].ee_loc;
	    int val;

	    if (BKPT0 (plst)->clr_step &&  BKPT0 (plst)->last_break == idx) {
		BKPT0 (plst)->clr_step = 0; /* not needed */
	    }
		/* Neighboring bytes can have breakpoints too... */
	    if (! terminated) {
		setErrno (0);
		val = TgtPtrace(RPT_PEEKTEXT, plst->pid, addr, 0, NULL);
		if (getErrno()) {
		    DPRINTF (("BreakClear: addr %x not readable!\n", addr));
		    setErrno (0);	/* Forget bkpt */
		} else {
		    assert (IS_BREAK (val));
		    val = ORG_BREAK (val, (int)plst->break_list[idx].ee_type);
		    TgtPtrace(RPT_POKETEXT, plst->pid, addr, val, NULL);
		    if (getErrno()) {
			DPRINTF (("BreakClear: addr %x not writable!\n", addr));
			setErrno (0);
		    }
		}
	    }
	    ++cleared;		/* indicate cleared */
	}
	memset(&plst->break_list[idx], 0, sizeof(xdr_break));
    }
    assert (!clearStepEmul || cleared <= stepEmulCount);
    if (stepEmulCount && cleared == 0) {
	DPRINTF (("BreakClear: all STEPEMUL bkpts were shared\n"));
	return 1;
    }
    return cleared;
}

/*----- Hiding of breakpoints -----*/

    /*
     *  PatchBreak - patch original data from break into data buffer.
     *
     * Notes:
     *  - this routine patches the original data under a break into the data
     *    buffer from a ptrace read/peek. 
     */

    static void
PatchBreak (char* buff, UINT32 bstart, int bsize, UINT32 dstart, char* dvalue)
{
    int		size = BREAK_SIZE; /* default size */

	/* Must deal with all sorts of unalignments
	 * (3 full overlaps, 3 unaligns)
	 */
    if (bsize < BREAK_SIZE) {
	    /* case where buffer is smaller than data */
	memcpy(buff, dvalue+(bstart-dstart), bsize); /* copy over */
	return;
    }
  	/* buffer larger than data.
	 * we need to see where break fits in buffer and whether
	 * we have part of it off the end. We set bstart to be the
	 * buffer offset, dtart to be the break data offset, and
	 * size to be the amount to copy
	 */
    if (dstart < bstart) {
	    /* break before actual buffer */
	dstart = bstart-dstart;	/* offset in data */
	size -= dstart;		/* amount to copy */
	bstart = 0;		/* offset in buffer */

    } else if (dstart + size > bstart + bsize) {
	    /* off end */
	bstart += bsize;		/* end of buffer */
	size -= (dstart + size) - bstart;
	bstart = bsize - size;	/* come back into buffer enough */
	dstart = 0;		/* start of data */

    } else {				/* normal case */
	bstart = dstart - bstart;	/* offset in buffer */
	dstart = 0;
    }
    memcpy(buff+bstart, dvalue+dstart, size);
}

    void
BreakHide (const PID_LIST* plst, void* addr, int data, void* addr2)
{
    int idx;

    if (!plst->break_list) 	/* no breaks exist, so skip this */
	return;

	/* if breakpoints, replace */

    for (idx = 1; idx < (int)plst->break_alloc; idx++) {
	int type = plst->break_list[idx].type;

	if (type != BRKT_INSTR && type != BRKT_STEPEMUL) {
	    continue;
	}
	    /* break, see if overlaps */
	if (BKPT_OVER (plst, idx, addr, data)) {

		/* overlaps, patch in old value */
	    PatchBreak((char *)addr2, (UINT32)addr, data, 
		plst->break_list[idx].ee_loc, 
		(char *)&plst->break_list[idx].ee_type);
	}
    }
}

/*----- Checking of breakpoint overwrites -----*/

    /*
     *  BreakOverwrite - check if memory write does not involve addresses
     *  having software breakpoints.
     */

    int
BreakOverwrite (const PID_LIST* plst, const char* addr, unsigned int size)
{
    int idx;

    if (!plst->break_list) { 	/* No breaks exist */
	return 0;
    }

    for (idx = 1; idx < (int)plst->break_alloc; idx++) {
	int type = plst->break_list[idx].type;

	    /* Consider only breakpoints involving modified memory */
	if (type != BRKT_INSTR && type != BRKT_STEPEMUL) {
	    continue;
	}
	if (BKPT_OVER (plst, idx, addr, size)) {
	    return -1;	/* overlaps */
	}
    }
    return 0;
}

/*----- Execution support -----*/

    /*
     *  BreakStepRange - Start stepping in a range.
     *
     *  Range is saved in breakpoint 0.
     */

    int
BreakStepRange (PID_LIST* plst, void* addr, int len)
{
    if (!plst->break_list) {
	    /* get list */
	if (BreakAlloc (plst, False) == -1) { /* must not be any memory */
	    setErrno(ENOMEM);	/* to be safe */
	    return -1;		/* fails */
	}
    }
    BKPT0 (plst)->range_start = (UINT32)addr;
    BKPT0 (plst)->range_end = (UINT32)addr+(len-1);
    return 0;
}

    /*
     *  If the Program Counter is changed, consider that the
     *  current breakpoint has not been reached yet.
     */

    void
BreakPcChanged (PID_LIST* plst)
{
    if (plst->break_list) {
	    /* clear break stuff */
	BKPT0 (plst)->clr_step = False;
    }
}

    /*
     *  BreakStepOff - prepare stepping off a breakpoint.
     */

    int
BreakStepOff (const PID_LIST* plst, void** paddr2)
{
    if (plst->break_list  &&  BKPT0 (plst)->clr_step) {

	    /* need clear then step off break */
	int last = BKPT0 (plst)->last_break;

	    /* clear break, step, then do exec */

	*paddr2 = (void*) plst->break_list[last].ee_type;

	    /* Need to clr_step after TgtPtrace() when wait() returns */
	return 1;
    }
    return 0;
}

    /*
     *	BreakSteppedOff - check if just stepped off a breakpoint
     *  and re-insert it into the code.
     */

    void
BreakSteppedOff (PID_LIST* plst)
{
    if (plst->break_list  &&  BKPT0 (plst)->clr_step) {
	int idx = BKPT0 (plst)->last_break;
	int data;

	BKPT0 (plst)->clr_step = 0;

	/*
	 *  Re-insert the breakpoint.
	 */
	data = TgtPtrace (RPT_PEEKTEXT, plst->pid,
			  (char *)plst->break_list [idx].ee_loc, 0, NULL);
	assert (! IS_BREAK (data));
	TgtPtrace (RPT_POKETEXT, plst->pid,
		   (char *)plst->break_list[idx].ee_loc,
		   (int) SET_BREAK (data), NULL);
    }
}


    /*
     *  Returns whether a thread matches a breakpoint.
     */

    static int
BreakThreadMatch (xdr_break* xb, int thread)
{
    int slot;

    if (thread < 0) return 1;	/* Break existence check only */

    if (xb->thread_list [0] == 0) return 1;	/* Universal break */

    for (slot = 0; slot < BKPT_SLOTS; ++slot) {
	if (xb->thread_list [slot] == 0) return 0;	/* End of list */
	if (xb->thread_list [slot] == thread) return 1;	/* Match */
    }
    return 0;		/* No matches found */
}


int
BreakAdjustPC (PID_LIST* plst)
{
	/* 
	 *  BREAK_ADJ is the value by which the Program Counter
	 *  has to be decremented after a software breakpoint
	 *  is hit. It must be defined and can be zero.
	 */
#if BREAK_ADJ
	/* subtract back if necessary */
    plst->regs.REG_PC -= BREAK_ADJ; /* now write back */
    TgtPtrace(RPT_SETREGS, plst->pid, (char *)&plst->regs, 0, NULL);
#else
    (void) plst;
#endif
    return 0;
}


/*
 *  Identify the current breakpoint. The process just stopped.
 */

    int
BreakIdentify (PID_LIST* plst, int adjust, int thread)
{
    int foreignBkpt = 0;
    int bidx;

    for (bidx = 1; bidx < (int) plst->break_alloc; bidx++) {
	int type = plst->break_list[bidx].type;

	if ((type == BRKT_INSTR || type == BRKT_STEPEMUL)
		&&  plst->regs.REG_PC - BREAK_ADJ
		== plst->break_list[bidx].ee_loc) {	/* found matching */
	    if (!BreakThreadMatch (&plst->break_list[bidx], thread)) {
		if (foreignBkpt == 0) {
		    foreignBkpt = bidx;
		}
		continue;
	    }
	    if (adjust) {
		BreakAdjustPC (plst);
	    }
	    return bidx;
	}
    }
    if (foreignBkpt) {
	if (adjust) {
	    BreakAdjustPC (plst);
	}
	return -foreignBkpt;
    }
    return 0;
}