source: rtems/c/src/librdbg/src/servtgt.c @ 4721cf1

/*
 **************************************************************************
 *
 *  Component:  RDB servers
 *  Module:     servtgt.c
 *
 **************************************************************************
 */


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

#ifdef DDEBUG
#define Ptrace  TgtDbgPtrace
#else
#define Ptrace  TgtRealPtrace
#endif

/* ----------------------------------------------------------------
   TgtBreakRestoreOrig - Restore original instruction at "addr"
                      just before single-stepping it.
   ---------------------------------------------------------------- */

int TgtBreakRestoreOrig (int pid, void *addr, void *addr2)
                /* Process identifier */
                /* Breakpoint address */
                /* Original instruction or bkpt number */
{
  int ret;
  int l;
  
  l = (long)Ptrace(RPT_PEEKTEXT, pid, addr, 0, NULL); /* assume ok */
  ret = ORG_BREAK (l, (UINT32) addr2);  /* reconstruct old instr */
  ret = Ptrace(RPT_POKETEXT, pid, addr, ret, NULL); /* poke back old */
  return ret;
}

/* -----------------------------------------------------------------------
   TgtBreakCancelStep - Restore the breakpoint at "addr" if the single-step
                has failed at the ptrace level.
   ----------------------------------------------------------------------- */

#define BKPT0(plst)     ((BASE_BREAK*)(plst)->break_list)

void TgtBreakCancelStep (PID_LIST* plst)
{
  assert (plst->break_list);
  assert (BKPT0 (plst)->clr_step);

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

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

/* -----------------------------------------------------------------------
   TgtCreateNew - add a new process into the process management lists.
   ----------------------------------------------------------------------- */

    void
TgtCreateNew(PID pid, int conn, INT32 child, char *name, Boolean spawn)
{
  int           idx;

  for (idx = 0; idx < pid_list_cnt; idx++)
    if (!pid_list[idx].pid)
      break;                    /* find empty */

  if (idx >= pid_list_cnt)
  {                             /* no empties, add more */
    PID_LIST    *tmp_pid_list = pid_list;

    pid_list_cnt += PID_LIST_INC;
    pid_list = (PID_LIST*) Realloc(pid_list,  /* get new or extend */
                                   pid_list_cnt * sizeof(PID_LIST));
    if (!pid_list)
    {                           /* out of memory */
      pid_list_cnt -= PID_LIST_INC;
      if (pid_list_cnt)
      {                         /* realloc failed - malloc again */
        pid_list = tmp_pid_list;
        /* above relies on old pointer being valid after failed realloc */
      }
      return;                   /* failed */
    }
    /* now clear newly added space */
    memset(pid_list+pid_list_cnt-PID_LIST_INC, 0,
        PID_LIST_INC * sizeof(PID_LIST));
    idx = pid_list_cnt - PID_LIST_INC;
  }
  else                          /* clear entry we found */
    memset(&pid_list[idx], 0, sizeof(PID_LIST));

  /* now fill in empty entry */
  pid_list[idx].pid = pid;
  pid_list[idx].running = 1;    /* we have not called wait yet */
  pid_list[idx].primary_conn = (UCHAR)conn; /* primary owner */
  if (conn != -1)
  {                             /* found caller */
    pid_list[idx].owners = 1;
    PIDMAP_SET (conn, idx);     /* mask in */
  }
  pid_list[idx].thread = (UINT32)-1; /* no thread for now */
  pid_list[idx].last_start = LAST_START; /* handle MiX bug */

  pid_list[idx].name = name  ? (char *)StrDup(name) : (char *)NULL;

}

/* -----------------------------------------------------------------------
   TgtNotifyWaitChange - send event to clients indicating child changed state.
   ----------------------------------------------------------------------- */

    void
TgtNotifyWaitChange( PID pid, int status, Boolean exclude)
{
  int           conn, idx;

  idx = FindPidEntry (pid);     /* locate the pid that changed */
  if (idx < 0)
  {
    DPRINTF(("TgtNotifyWaitChange: pid %d not in our list\n",
        (int) pid));
    return;                     /* not in our list */
  }
  pid_list[idx].running = 0;    /* not running */
  pid_list[idx].state = status; /* save status of stop/term */
  if (!pid_list[idx].owners && !STS_SIGNALLED(status))
    TgtDelete(&pid_list[idx], -1, 0);   /* terminated and no owners */
  else
  {                             /* normal cases */
    for (conn = 0; conn < conn_list_cnt; conn++)
    {                           /* now find all interested clients */
      if (!conn_list[conn].in_use       /* free entry */
      ||  ! PIDMAP_TEST (conn, idx))
        continue;               /* not using this pid */
      if (conn == exclude)
        continue;               /* do not do this one */
      TspSendWaitChange(conn, BMSG_WAIT, 1, pid, 0, False);/* notify of change */
    }
  }
}

/* -----------------------------------------------------------------------
   TgtNotifyAll - send a message to all clients interested in process.
   ----------------------------------------------------------------------- */

    void
    TgtNotifyAll( int pid_idx, BACK_MSG msg, UINT16 spec,
                  UINT32 context, int exclude, Boolean force)
{
  int           conn;

  DPRINTF(("TgtNotifyAll: msg %d (%s) for pid_idx=%d (%d,%d)\n",
        msg, BmsgNames [msg], pid_idx, exclude, force));
  for (conn = 0; conn < conn_list_cnt; conn++)
    if (conn_list[conn].in_use /* not free */
    &&  PIDMAP_TEST (conn, pid_idx))
    {
      if (conn != exclude)
        TspSendWaitChange(conn, msg, spec, pid_list[pid_idx].pid, context, 
                                force);
    }
}

/* -----------------------------------------------------------------------
   TgtDelete - mark process as now uncontrolled.

   Notes:
      - this function removes a process from the process list.
      - the notify argument indicates a message to send if needed.
   ----------------------------------------------------------------------- */

void TgtDelete(PID_LIST *plst, int conn_idx, BACK_MSG notify)
{
  int           idx = plst - pid_list, cnt, conn;

    /* found */
  cnt = pid_list[idx].owners;
  if (cnt)
  {                             /* some connections to break */
    for (conn = 0; cnt && conn < conn_list_cnt; conn++)
      if (conn_list[conn].in_use /* not free */
      &&  PIDMAP_TEST (conn, idx))
      {                         /* found one that uses it */
        PIDMAP_CLEAR (conn, idx);
        if (notify && conn != conn_idx)
          TspSendWaitChange(conn, notify, 0, plst->pid, 0, True);
        if (!--cnt)
          break;
      }
  }
  if (pid_list[idx].name)
    Free(pid_list[idx].name);   /* free string name back */
    /* Free breakpoint list */
  if (pid_list [idx].break_list != NULL) {
    Free (pid_list [idx].break_list);
  }
  pid_list[idx].pid = 0;        /* gone */
}


/* -----------------------------------------------------------------------
   TgtKillAndDelete - kill or detach process and remove entry.
   ----------------------------------------------------------------------- */

    int
TgtKillAndDelete( PID_LIST *plst, struct svc_req *rqstp, Boolean term)
{
  ptrace_in     pin;            /* used for ptrace call */
  ptrace_out    *pout;

  /* Remove breakpoints */
  if (plst->break_alloc > 0) {
    pin.pid = plst->pid;
    pin.addr.req = RPT_CLRBREAK;
    pin.data = 0;               /* clear all */
    pin.flags = PTRFLG_NON_OWNER;
    pout = RPCGENSRVNAME(ptrace_2_svc) (&pin, rqstp);
    if (pout->result < 0) {
      DPRINTF (("TgtKillAndDelete: RPT_CLRBREAK failed %d\n",
        getErrno()));
      return -1;
    }
  }

  if (term)
  {                             /* kill */
    pin.addr.ptrace_addr_data_in_u.address = 0;
    pin.data = -1;              /* Don't want notification from slave */
    pin.addr.req = RPT_KILL;
  }
  else
  {                             /* detach */
    pin.addr.ptrace_addr_data_in_u.address = 1;
    pin.data = 0;
    pin.addr.req = RPT_DETACH;
  }
  pin.pid = plst->pid;
  pin.flags = PTRFLG_FREE | PTRFLG_NON_OWNER;

  DPRINTF (("TgtKillAndDelete: ptrace_2_svc (%s (%d), %d)\n",
      PtraceName (pin.addr.req), pin.addr.req, pin.pid));

  pout = RPCGENSRVNAME(ptrace_2_svc) (&pin, rqstp);/* start it */
  if (pout->errNo == ESRCH && plst->pid)
    TgtDelete(plst, -1, BMSG_KILLED); /* only entry remains */
  return 0;
}

/* -----------------------------------------------------------------------
   TgtDetachCon - detach a connection's ownership of a process.
   ----------------------------------------------------------------------- */

    void
TgtDetachCon( int conn_idx, int pid_idx, Boolean delete)
{
  if ((unsigned) pid_idx >= pid_list_cnt
  ||  !pid_list[pid_idx].pid)
    return;                     /* not valid */
  if (PIDMAP_TEST (conn_idx, pid_idx))
  {                             /* if an owner, release control */
    PIDMAP_CLEAR (conn_idx, pid_idx);

    if (pid_list[pid_idx].owners)
      pid_list[pid_idx].owners--;
    if (pid_list[pid_idx].primary_conn == conn_idx)
      pid_list[pid_idx].primary_conn = NO_PRIMARY;
    if (delete
    &&  !pid_list[pid_idx].owners
    &&  PROC_TERMINATED (pid_list + pid_idx))
      TgtDelete(&pid_list[pid_idx], -1, 0); /* remove entry */
  }
}

/* -----------------------------------------------------------------------
   TgtHandleChildChange - decide what action to take after wait() returns.
                Used in the master only.
   ----------------------------------------------------------------------- */

#ifdef DDEBUG
static char* LastStartNames[] = {
  "NONE", "STEP", "CONT", "RANGE",
  "STEPOFF", "KILLED", "DETACHED"
};

char* GetLastStartName (int last_start)
{
    static char buf [32];

    strcpy (buf, LastStartNames [last_start & ~LAST_START]);
    if (last_start & LAST_START) {
        strcat (buf, "+START");
    }
    return buf;
}
#endif

Boolean TgtHandleChildChange(PID pid, int* status, int *unexp,
                             CPU_Exception_frame* ctx)
{                               /* return False if continue, else stop */
  int           idx, sig;
  int           bidx = 0;
  PID_LIST      *plst;
  unsigned long PC;
  BASE_BREAK    *base = NULL;   /* break_list[0] is really BASE_BREAK */
  int           hadStepEmul;
  int           origHadStepEmul;
  int           stopWanted;

  DPRINTF (("TgtHandleChildChange: pid %d status %x cap\n",
    (int) pid, *status));
  if (unexp)
    *unexp = 0;                 /* initialize to ok */

  /* first, find pid in question */
  idx = FindPidEntry (pid);
  if (idx < 0)
  {                             /* cannot locate this process */
    DPRINTF (("TgtHandleChildChange: unknown process (%s pid)\n",
      FindPidEntry (pid) >= 0 ? "stale" : "unknown"));
    if (unexp)
      *unexp = 1;               /* Unexpected change */
    return(False);              /* unknown: ignore (used to stop and notify) */
  }

    /* found */
  plst = &pid_list[idx];        /* pointer to entry */
  /* first we see if just stopped */

  /* copy ctxt */
  CtxToRegs(ctx, &(plst->regs));

  stopWanted = plst->stop_wanted;
  plst->stop_wanted = 0;        /* For the next time */

  hadStepEmul = BreakClear (plst, -1, -1) > 0;
  origHadStepEmul = hadStepEmul;  /* hadStepEmul is cleared if real bkpt met */

  if (STS_SIGNALLED (*status))
  {                             /* stopped, not terminated */
    sig = STS_GETSIG (*status); /* signal that stopped us */

    /* now, we read the registers and see what to do next */
    if (TgtPtrace(RPT_GETREGS, pid, (void *)&plst->regs, 0, NULL) < 0) {
        memset (&plst->regs, 0, sizeof plst->regs);
    }

    /* Get current thread */
    plst->thread = TgtPtrace(RPT_GETTARGETTHREAD, pid, NULL, 0, NULL);

    if (sig == SIGTRAP)
    {                           /* stopped from break/step */
      PC = plst->regs.REG_PC;
        /* Must check PC to see whether in situations where we had
                step emulation we are on a breakpoint or just
                have returned from an emulated single-step */
      if (BreakIdentify (plst, 0 /*no adjust*/, -1 /*no thread*/) > 0) {
        hadStepEmul = 0;
      }
      plst->is_step = hadStepEmul || IS_STEP(plst->regs)
        || plst->last_start == LAST_START;
      DPRINTF (("TgtHandleChildChange: %s last_start %s\n", plst->is_step
        ? "step": "break", GetLastStartName (plst->last_start)));

      if ((plst->is_step || origHadStepEmul || stopWanted)
      &&  (plst->last_start == LAST_STEP
      ||  plst->last_start == LAST_STEPOFF
      ||  plst->last_start == LAST_RANGE))
      {
        DPRINTF (("TgtHandleChildChange: restoring stepped-off bkpt\n"));
        BreakSteppedOff (plst);
      }

      if (plst->last_start == LAST_STEPOFF && (plst->is_step||origHadStepEmul))
      {                         /* stepped off break and now need cont */
        DPRINTF (("TgtHandleChildChange: auto-resuming after step-off\n"));
        plst->last_start = LAST_CONT; /* convert to normal cont */
        if (!stopWanted) {
          if (TgtPtrace(RPT_CONT, pid, (char *)1, 0, NULL))
            return True;                /* tell people */
          return(False);                /* wait for change */
        }
        DPRINTF (("TgtHandleChildChange: stop_wanted %d in step-off\n",
          stopWanted));
        *status = STS_MAKESIG (stopWanted);
        return True;    /* Stop and notify */
      }

      base = plst->break_list ? ((BASE_BREAK*)plst->break_list) :
                                ((BASE_BREAK*)NULL);
      /* now see if step in range */

      if (plst->last_start == LAST_RANGE /* step in range */
      &&  (plst->is_step || origHadStepEmul)    /* not a breakpoint */
      &&  PC >= base->range_start
      &&  PC <= base->range_end)
      {                         /* still in range, keep going */
        if (stopWanted) {
          DPRINTF (("TgtHandleChildChange: stop_wanted %d in step-range\n",
            stopWanted));
        } else {
          DPRINTF (("TgtHandleChildChange: Reservation at %x\n",
            plst->regs.REG_PC));
        }
      }
      if (!plst->is_step)               /* was break */
      {
        bidx = BreakIdentify (plst, 1 /*adjust*/, plst->thread);
        if (bidx == 0) {
          DPRINTF (("TgtHandleChildChange: forwarding bkpt to kernel\n"));
          if (unexp) {
            *unexp = 1;
          }
          return False;
        }
        if (bidx < 0) { /* Unwanted breakpoint, must step it off */
          ptrace_in pin;
          ptrace_out* out;
          if (origHadStepEmul)
          {
            DPRINTF (("TgtHandleChildChange: bkpt %x becomes step\n",
              plst->regs.REG_PC));
            bidx = -bidx;
            plst->is_step = 1;
            base->clr_step = plst->break_list [bidx].type == BRKT_INSTR;
            base->last_break = bidx;
            return True;
          }
          if (stopWanted) {
            DPRINTF (("TgtHandleChildChange: stop_wanted %d at bkpt %x\n",
              stopWanted, plst->regs.REG_PC));
              /* The PC has already been adjusted by BreakIdentify */
            *status = STS_MAKESIG (stopWanted);
            return True;
          }
            /* All the handling is done in ptrace_2_svc() so call it */
          bidx = -bidx;
          DPRINTF (("TgtHandleChildChange: last %d (%s) restarting bkpt %d\n",
            plst->last_start, GetLastStartName (plst->last_start), bidx));
          base->clr_step = 1;
          base->last_break = bidx; /* remember which one */
          plst->running = 0;    /* So that ptrace is accepted */
          pin.pid = plst->pid;

          if (plst->last_start == LAST_STEP) {
            pin.addr.req = RPT_SINGLESTEP;
          } else {
            pin.addr.req = RPT_CONT;
          }
          pin.addr.ptrace_addr_data_in_u.address = 1;
          pin.data = 0;
          pin.flags = PTRFLG_NON_OWNER;
          out = RPCGENSRVNAME(ptrace_2_svc) (&pin, NULL);
          if (out->result == 0) return False;   /* Continue waiting */
          DPRINTF(("TgtHandleChildChange: failed to restart bkpt!\n"));
            /* If something went wrong, just stop on breakpoint */
        }
      }
    }           /* else sig != SIGTRAP */

    /* finally, fill in stop info in break point array base */
    if (bidx > 0)
    {                           /* store break info */
        /* will need to get off the break for SW breakpoints only */
      base->clr_step = plst->break_list [bidx].type == BRKT_INSTR;
      base->last_break = bidx; /* remember which one */
    }
    else if (base)
    {                           /* clear break info */
      base->clr_step = False;   /* not stopped on break */
      base->last_break = 0;
    }
    /* decision to notify owner based on last_start */
  }                             /* stopped */
  else                          /* terminated */
  {
    if (plst->last_start == LAST_START)
    {                           /* spawn failed */
      TgtNotifyAll(idx, BMSG_EXEC_FAIL, 0, 0, -1, True);
      plst->running = False;    /* not running - dead */
      plst->state = *status;    /* contains errno in high word */
      return(False);
    }
 
    else if ((UCHAR)(plst->last_start & ~LAST_START) < (UCHAR)LAST_KILLED)
      plst->last_start = LAST_NONE; /* doesn't matter anymore */
    else
      return(False);            /* killed and detach already notified */
  }
  return(True);                 /* stop and notify */
}

#ifdef DDEBUG

/* -----------------------------------------------------------------------
   TgtDbgPtrace - debug version of ptrace.
   ----------------------------------------------------------------------- */

int TgtDbgPtrace(int request, PID pid, char *addr, int data, void *addr2)
{
  int           diag;

  DPRINTF (("TgtDbgPtrace: entered (%s (%d), %d, %x, %d, %x)\n",
      PtraceName (request), request, pid, (int) addr, data,
      (int) addr2));

  if (request == RPT_WRITETEXT || request == RPT_WRITEDATA) {
    int i;

    DPRINTF (("TgtDbgPtrace:"));
    if (rdb_debug) {
      for (i = 0; i < data && i < 16; ++i) {
        printf (" %02x", ((char*) addr2) [i] & 0xFF);
      }
      printf ("\n");
    }
  }

  diag = TgtRealPtrace (request, pid, addr, data, addr2);

  DPRINTF (("TgtDbgPtrace: returned %d (%x) errno %d\n",
      diag, diag, getErrno()));

  if (request == RPT_GETREGS || request == RPT_GETTHREADREGS
   || request == RPT_SETREGS || request == RPT_SETTHREADREGS)
  {
      /* Use DPRINTF() so as to have the id prefix */
    DPRINTF (("TgtDbgPtrace: (%s) PC = %x, SP = %x, FP = %x\n",
      PtraceName (request),
      ((xdr_regs*)addr)->REG_PC,
      ((xdr_regs*)addr)->REG_SP,
      ((xdr_regs*)addr)->REG_FP));
  }

  return(diag);
}
#endif                          /* DDEBUG */