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/*

 **********************************************************************

 *

 *  Component:  RDB servers

 *  Module:     servbkpt.c

 *

 *  Synopsis:   Management of breakpoints

 *

 * $Id: servbkpt.c,v 1.2 2001-09-27 12:02:01 chris Exp $

 *

 **********************************************************************

 */

#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;

}