clang-tests-external/gdb/7.5/gdb/remote.c

/* Remote target communications for serial-line targets in custom GDB protocol

   Copyright (C) 1988-2012 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* See the GDB User Guide for details of the GDB remote protocol.  */

#include "defs.h"
#include "gdb_string.h"
#include <ctype.h>
#include <fcntl.h>
#include "inferior.h"
#include "bfd.h"
#include "symfile.h"
#include "exceptions.h"
#include "target.h"
/*#include "terminal.h" */
#include "gdbcmd.h"
#include "objfiles.h"
#include "gdb-stabs.h"
#include "gdbthread.h"
#include "remote.h"
#include "regcache.h"
#include "value.h"
#include "gdb_assert.h"
#include "observer.h"
#include "solib.h"
#include "cli/cli-decode.h"
#include "cli/cli-setshow.h"
#include "target-descriptions.h"

#include <ctype.h>
#include <sys/time.h>

#include "event-loop.h"
#include "event-top.h"
#include "inf-loop.h"

#include <signal.h>
#include "serial.h"

#include "gdbcore.h" /* for exec_bfd */

#include "remote-fileio.h"
#include "gdb/fileio.h"
#include "gdb_stat.h"
#include "xml-support.h"

#include "memory-map.h"

#include "tracepoint.h"
#include "ax.h"
#include "ax-gdb.h"
#include "agent.h"

/* Temp hacks for tracepoint encoding migration.  */
static char *target_buf;
static long target_buf_size;

/* The size to align memory write packets, when practical.  The protocol
   does not guarantee any alignment, and gdb will generate short
   writes and unaligned writes, but even as a best-effort attempt this
   can improve bulk transfers.  For instance, if a write is misaligned
   relative to the target's data bus, the stub may need to make an extra
   round trip fetching data from the target.  This doesn't make a
   huge difference, but it's easy to do, so we try to be helpful.

   The alignment chosen is arbitrary; usually data bus width is
   important here, not the possibly larger cache line size.  */
enum { REMOTE_ALIGN_WRITES = 16 };

/* Prototypes for local functions.  */
static void cleanup_sigint_signal_handler (void *dummy);
static void initialize_sigint_signal_handler (void);
static int getpkt_sane (char **buf, long *sizeof_buf, int forever);
static int getpkt_or_notif_sane (char **buf, long *sizeof_buf,
				 int forever);

static void handle_remote_sigint (int);
static void handle_remote_sigint_twice (int);
static void async_remote_interrupt (gdb_client_data);
void async_remote_interrupt_twice (gdb_client_data);

static void remote_files_info (struct target_ops *ignore);

static void remote_prepare_to_store (struct regcache *regcache);

static void remote_open (char *name, int from_tty);

static void extended_remote_open (char *name, int from_tty);

static void remote_open_1 (char *, int, struct target_ops *, int extended_p);

static void remote_close (int quitting);

static void remote_mourn (struct target_ops *ops);

static void extended_remote_restart (void);

static void extended_remote_mourn (struct target_ops *);

static void remote_mourn_1 (struct target_ops *);

static void remote_send (char **buf, long *sizeof_buf_p);

static int readchar (int timeout);

static void remote_kill (struct target_ops *ops);

static int tohex (int nib);

static int remote_can_async_p (void);

static int remote_is_async_p (void);

static void remote_async (void (*callback) (enum inferior_event_type event_type,
					    void *context), void *context);

static void remote_detach (struct target_ops *ops, char *args, int from_tty);

static void remote_interrupt (int signo);

static void remote_interrupt_twice (int signo);

static void interrupt_query (void);

static void set_general_thread (struct ptid ptid);
static void set_continue_thread (struct ptid ptid);

static void get_offsets (void);

static void skip_frame (void);

static long read_frame (char **buf_p, long *sizeof_buf);

static int hexnumlen (ULONGEST num);

static void init_remote_ops (void);

static void init_extended_remote_ops (void);

static void remote_stop (ptid_t);

static int ishex (int ch, int *val);

static int stubhex (int ch);

static int hexnumstr (char *, ULONGEST);

static int hexnumnstr (char *, ULONGEST, int);

static CORE_ADDR remote_address_masked (CORE_ADDR);

static void print_packet (char *);

static void compare_sections_command (char *, int);

static void packet_command (char *, int);

static int stub_unpack_int (char *buff, int fieldlength);

static ptid_t remote_current_thread (ptid_t oldptid);

static void remote_find_new_threads (void);

static void record_currthread (ptid_t currthread);

static int fromhex (int a);

extern int hex2bin (const char *hex, gdb_byte *bin, int count);

extern int bin2hex (const gdb_byte *bin, char *hex, int count);

static int putpkt_binary (char *buf, int cnt);

static void check_binary_download (CORE_ADDR addr);

struct packet_config;

static void show_packet_config_cmd (struct packet_config *config);

static void update_packet_config (struct packet_config *config);

static void set_remote_protocol_packet_cmd (char *args, int from_tty,
					    struct cmd_list_element *c);

static void show_remote_protocol_packet_cmd (struct ui_file *file,
					     int from_tty,
					     struct cmd_list_element *c,
					     const char *value);

static char *write_ptid (char *buf, const char *endbuf, ptid_t ptid);
static ptid_t read_ptid (char *buf, char **obuf);

static void remote_set_permissions (void);

struct remote_state;
static int remote_get_trace_status (struct trace_status *ts);

static int remote_upload_tracepoints (struct uploaded_tp **utpp);

static int remote_upload_trace_state_variables (struct uploaded_tsv **utsvp);
  
static void remote_query_supported (void);

static void remote_check_symbols (struct objfile *objfile);

void _initialize_remote (void);

struct stop_reply;
static struct stop_reply *stop_reply_xmalloc (void);
static void stop_reply_xfree (struct stop_reply *);
static void do_stop_reply_xfree (void *arg);
static void remote_parse_stop_reply (char *buf, struct stop_reply *);
static void push_stop_reply (struct stop_reply *);
static void remote_get_pending_stop_replies (void);
static void discard_pending_stop_replies (int pid);
static int peek_stop_reply (ptid_t ptid);

static void remote_async_inferior_event_handler (gdb_client_data);
static void remote_async_get_pending_events_handler (gdb_client_data);

static void remote_terminal_ours (void);

static int remote_read_description_p (struct target_ops *target);

static void remote_console_output (char *msg);

static int remote_supports_cond_breakpoints (void);

static int remote_can_run_breakpoint_commands (void);

/* The non-stop remote protocol provisions for one pending stop reply.
   This is where we keep it until it is acknowledged.  */

static struct stop_reply *pending_stop_reply = NULL;

/* For "remote".  */

static struct cmd_list_element *remote_cmdlist;

/* For "set remote" and "show remote".  */

static struct cmd_list_element *remote_set_cmdlist;
static struct cmd_list_element *remote_show_cmdlist;

/* Description of the remote protocol state for the currently
   connected target.  This is per-target state, and independent of the
   selected architecture.  */

struct remote_state
{
  /* A buffer to use for incoming packets, and its current size.  The
     buffer is grown dynamically for larger incoming packets.
     Outgoing packets may also be constructed in this buffer.
     BUF_SIZE is always at least REMOTE_PACKET_SIZE;
     REMOTE_PACKET_SIZE should be used to limit the length of outgoing
     packets.  */
  char *buf;
  long buf_size;

  /* True if we're going through initial connection setup (finding out
     about the remote side's threads, relocating symbols, etc.).  */
  int starting_up;

  /* If we negotiated packet size explicitly (and thus can bypass
     heuristics for the largest packet size that will not overflow
     a buffer in the stub), this will be set to that packet size.
     Otherwise zero, meaning to use the guessed size.  */
  long explicit_packet_size;

  /* remote_wait is normally called when the target is running and
     waits for a stop reply packet.  But sometimes we need to call it
     when the target is already stopped.  We can send a "?" packet
     and have remote_wait read the response.  Or, if we already have
     the response, we can stash it in BUF and tell remote_wait to
     skip calling getpkt.  This flag is set when BUF contains a
     stop reply packet and the target is not waiting.  */
  int cached_wait_status;

  /* True, if in no ack mode.  That is, neither GDB nor the stub will
     expect acks from each other.  The connection is assumed to be
     reliable.  */
  int noack_mode;

  /* True if we're connected in extended remote mode.  */
  int extended;

  /* True if the stub reported support for multi-process
     extensions.  */
  int multi_process_aware;

  /* True if we resumed the target and we're waiting for the target to
     stop.  In the mean time, we can't start another command/query.
     The remote server wouldn't be ready to process it, so we'd
     timeout waiting for a reply that would never come and eventually
     we'd close the connection.  This can happen in asynchronous mode
     because we allow GDB commands while the target is running.  */
  int waiting_for_stop_reply;

  /* True if the stub reports support for non-stop mode.  */
  int non_stop_aware;

  /* True if the stub reports support for vCont;t.  */
  int support_vCont_t;

  /* True if the stub reports support for conditional tracepoints.  */
  int cond_tracepoints;

  /* True if the stub reports support for target-side breakpoint
     conditions.  */
  int cond_breakpoints;

  /* True if the stub reports support for target-side breakpoint
     commands.  */
  int breakpoint_commands;

  /* True if the stub reports support for fast tracepoints.  */
  int fast_tracepoints;

  /* True if the stub reports support for static tracepoints.  */
  int static_tracepoints;

  /* True if the stub reports support for installing tracepoint while
     tracing.  */
  int install_in_trace;

  /* True if the stub can continue running a trace while GDB is
     disconnected.  */
  int disconnected_tracing;

  /* True if the stub reports support for enabling and disabling
     tracepoints while a trace experiment is running.  */
  int enable_disable_tracepoints;

  /* True if the stub can collect strings using tracenz bytecode.  */
  int string_tracing;

  /* Nonzero if the user has pressed Ctrl-C, but the target hasn't
     responded to that.  */
  int ctrlc_pending_p;
};

/* Private data that we'll store in (struct thread_info)->private.  */
struct private_thread_info
{
  char *extra;
  int core;
};

static void
free_private_thread_info (struct private_thread_info *info)
{
  xfree (info->extra);
  xfree (info);
}

/* Returns true if the multi-process extensions are in effect.  */
static int
remote_multi_process_p (struct remote_state *rs)
{
  return rs->multi_process_aware;
}

/* This data could be associated with a target, but we do not always
   have access to the current target when we need it, so for now it is
   static.  This will be fine for as long as only one target is in use
   at a time.  */
static struct remote_state remote_state;

static struct remote_state *
get_remote_state_raw (void)
{
  return &remote_state;
}

/* Description of the remote protocol for a given architecture.  */

struct packet_reg
{
  long offset; /* Offset into G packet.  */
  long regnum; /* GDB's internal register number.  */
  LONGEST pnum; /* Remote protocol register number.  */
  int in_g_packet; /* Always part of G packet.  */
  /* long size in bytes;  == register_size (target_gdbarch, regnum);
     at present.  */
  /* char *name; == gdbarch_register_name (target_gdbarch, regnum);
     at present.  */
};

struct remote_arch_state
{
  /* Description of the remote protocol registers.  */
  long sizeof_g_packet;

  /* Description of the remote protocol registers indexed by REGNUM
     (making an array gdbarch_num_regs in size).  */
  struct packet_reg *regs;

  /* This is the size (in chars) of the first response to the ``g''
     packet.  It is used as a heuristic when determining the maximum
     size of memory-read and memory-write packets.  A target will
     typically only reserve a buffer large enough to hold the ``g''
     packet.  The size does not include packet overhead (headers and
     trailers).  */
  long actual_register_packet_size;

  /* This is the maximum size (in chars) of a non read/write packet.
     It is also used as a cap on the size of read/write packets.  */
  long remote_packet_size;
};

long sizeof_pkt = 2000;

/* Utility: generate error from an incoming stub packet.  */
static void
trace_error (char *buf)
{
  if (*buf++ != 'E')
    return;			/* not an error msg */
  switch (*buf)
    {
    case '1':			/* malformed packet error */
      if (*++buf == '0')	/*   general case: */
	error (_("remote.c: error in outgoing packet."));
      else
	error (_("remote.c: error in outgoing packet at field #%ld."),
	       strtol (buf, NULL, 16));
    case '2':
      error (_("trace API error 0x%s."), ++buf);
    default:
      error (_("Target returns error code '%s'."), buf);
    }
}

/* Utility: wait for reply from stub, while accepting "O" packets.  */
static char *
remote_get_noisy_reply (char **buf_p,
			long *sizeof_buf)
{
  do				/* Loop on reply from remote stub.  */
    {
      char *buf;

      QUIT;			/* Allow user to bail out with ^C.  */
      getpkt (buf_p, sizeof_buf, 0);
      buf = *buf_p;
      if (buf[0] == 'E')
	trace_error (buf);
      else if (strncmp (buf, "qRelocInsn:", strlen ("qRelocInsn:")) == 0)
	{
	  ULONGEST ul;
	  CORE_ADDR from, to, org_to;
	  char *p, *pp;
	  int adjusted_size = 0;
	  volatile struct gdb_exception ex;

	  p = buf + strlen ("qRelocInsn:");
	  pp = unpack_varlen_hex (p, &ul);
	  if (*pp != ';')
	    error (_("invalid qRelocInsn packet: %s"), buf);
	  from = ul;

	  p = pp + 1;
	  unpack_varlen_hex (p, &ul);
	  to = ul;

	  org_to = to;

	  TRY_CATCH (ex, RETURN_MASK_ALL)
	    {
	      gdbarch_relocate_instruction (target_gdbarch, &to, from);
	    }
	  if (ex.reason >= 0)
	    {
	      adjusted_size = to - org_to;

	      xsnprintf (buf, *sizeof_buf, "qRelocInsn:%x", adjusted_size);
	      putpkt (buf);
	    }
	  else if (ex.reason < 0 && ex.error == MEMORY_ERROR)
	    {
	      /* Propagate memory errors silently back to the target.
		 The stub may have limited the range of addresses we
		 can write to, for example.  */
	      putpkt ("E01");
	    }
	  else
	    {
	      /* Something unexpectedly bad happened.  Be verbose so
		 we can tell what, and propagate the error back to the
		 stub, so it doesn't get stuck waiting for a
		 response.  */
	      exception_fprintf (gdb_stderr, ex,
				 _("warning: relocating instruction: "));
	      putpkt ("E01");
	    }
	}
      else if (buf[0] == 'O' && buf[1] != 'K')
	remote_console_output (buf + 1);	/* 'O' message from stub */
      else
	return buf;		/* Here's the actual reply.  */
    }
  while (1);
}

/* Handle for retreving the remote protocol data from gdbarch.  */
static struct gdbarch_data *remote_gdbarch_data_handle;

static struct remote_arch_state *
get_remote_arch_state (void)
{
  return gdbarch_data (target_gdbarch, remote_gdbarch_data_handle);
}

/* Fetch the global remote target state.  */

static struct remote_state *
get_remote_state (void)
{
  /* Make sure that the remote architecture state has been
     initialized, because doing so might reallocate rs->buf.  Any
     function which calls getpkt also needs to be mindful of changes
     to rs->buf, but this call limits the number of places which run
     into trouble.  */
  get_remote_arch_state ();

  return get_remote_state_raw ();
}

static int
compare_pnums (const void *lhs_, const void *rhs_)
{
  const struct packet_reg * const *lhs = lhs_;
  const struct packet_reg * const *rhs = rhs_;

  if ((*lhs)->pnum < (*rhs)->pnum)
    return -1;
  else if ((*lhs)->pnum == (*rhs)->pnum)
    return 0;
  else
    return 1;
}

static int
map_regcache_remote_table (struct gdbarch *gdbarch, struct packet_reg *regs)
{
  int regnum, num_remote_regs, offset;
  struct packet_reg **remote_regs;

  for (regnum = 0; regnum < gdbarch_num_regs (gdbarch); regnum++)
    {
      struct packet_reg *r = &regs[regnum];

      if (register_size (gdbarch, regnum) == 0)
	/* Do not try to fetch zero-sized (placeholder) registers.  */
	r->pnum = -1;
      else
	r->pnum = gdbarch_remote_register_number (gdbarch, regnum);

      r->regnum = regnum;
    }

  /* Define the g/G packet format as the contents of each register
     with a remote protocol number, in order of ascending protocol
     number.  */

  remote_regs = alloca (gdbarch_num_regs (gdbarch)
			* sizeof (struct packet_reg *));
  for (num_remote_regs = 0, regnum = 0;
       regnum < gdbarch_num_regs (gdbarch);
       regnum++)
    if (regs[regnum].pnum != -1)
      remote_regs[num_remote_regs++] = &regs[regnum];

  qsort (remote_regs, num_remote_regs, sizeof (struct packet_reg *),
	 compare_pnums);

  for (regnum = 0, offset = 0; regnum < num_remote_regs; regnum++)
    {
      remote_regs[regnum]->in_g_packet = 1;
      remote_regs[regnum]->offset = offset;
      offset += register_size (gdbarch, remote_regs[regnum]->regnum);
    }

  return offset;
}

/* Given the architecture described by GDBARCH, return the remote
   protocol register's number and the register's offset in the g/G
   packets of GDB register REGNUM, in PNUM and POFFSET respectively.
   If the target does not have a mapping for REGNUM, return false,
   otherwise, return true.  */

int
remote_register_number_and_offset (struct gdbarch *gdbarch, int regnum,
				   int *pnum, int *poffset)
{
  int sizeof_g_packet;
  struct packet_reg *regs;
  struct cleanup *old_chain;

  gdb_assert (regnum < gdbarch_num_regs (gdbarch));

  regs = xcalloc (gdbarch_num_regs (gdbarch), sizeof (struct packet_reg));
  old_chain = make_cleanup (xfree, regs);

  sizeof_g_packet = map_regcache_remote_table (gdbarch, regs);

  *pnum = regs[regnum].pnum;
  *poffset = regs[regnum].offset;

  do_cleanups (old_chain);

  return *pnum != -1;
}

static void *
init_remote_state (struct gdbarch *gdbarch)
{
  struct remote_state *rs = get_remote_state_raw ();
  struct remote_arch_state *rsa;

  rsa = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct remote_arch_state);

  /* Use the architecture to build a regnum<->pnum table, which will be
     1:1 unless a feature set specifies otherwise.  */
  rsa->regs = GDBARCH_OBSTACK_CALLOC (gdbarch,
				      gdbarch_num_regs (gdbarch),
				      struct packet_reg);

  /* Record the maximum possible size of the g packet - it may turn out
     to be smaller.  */
  rsa->sizeof_g_packet = map_regcache_remote_table (gdbarch, rsa->regs);

  /* Default maximum number of characters in a packet body.  Many
     remote stubs have a hardwired buffer size of 400 bytes
     (c.f. BUFMAX in m68k-stub.c and i386-stub.c).  BUFMAX-1 is used
     as the maximum packet-size to ensure that the packet and an extra
     NUL character can always fit in the buffer.  This stops GDB
     trashing stubs that try to squeeze an extra NUL into what is
     already a full buffer (As of 1999-12-04 that was most stubs).  */
  rsa->remote_packet_size = 400 - 1;

  /* This one is filled in when a ``g'' packet is received.  */
  rsa->actual_register_packet_size = 0;

  /* Should rsa->sizeof_g_packet needs more space than the
     default, adjust the size accordingly.  Remember that each byte is
     encoded as two characters.  32 is the overhead for the packet
     header / footer.  NOTE: cagney/1999-10-26: I suspect that 8
     (``$NN:G...#NN'') is a better guess, the below has been padded a
     little.  */
  if (rsa->sizeof_g_packet > ((rsa->remote_packet_size - 32) / 2))
    rsa->remote_packet_size = (rsa->sizeof_g_packet * 2 + 32);

  /* Make sure that the packet buffer is plenty big enough for
     this architecture.  */
  if (rs->buf_size < rsa->remote_packet_size)
    {
      rs->buf_size = 2 * rsa->remote_packet_size;
      rs->buf = xrealloc (rs->buf, rs->buf_size);
    }

  return rsa;
}

/* Return the current allowed size of a remote packet.  This is
   inferred from the current architecture, and should be used to
   limit the length of outgoing packets.  */
static long
get_remote_packet_size (void)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();

  if (rs->explicit_packet_size)
    return rs->explicit_packet_size;

  return rsa->remote_packet_size;
}

static struct packet_reg *
packet_reg_from_regnum (struct remote_arch_state *rsa, long regnum)
{
  if (regnum < 0 && regnum >= gdbarch_num_regs (target_gdbarch))
    return NULL;
  else
    {
      struct packet_reg *r = &rsa->regs[regnum];

      gdb_assert (r->regnum == regnum);
      return r;
    }
}

static struct packet_reg *
packet_reg_from_pnum (struct remote_arch_state *rsa, LONGEST pnum)
{
  int i;

  for (i = 0; i < gdbarch_num_regs (target_gdbarch); i++)
    {
      struct packet_reg *r = &rsa->regs[i];

      if (r->pnum == pnum)
	return r;
    }
  return NULL;
}

/* FIXME: graces/2002-08-08: These variables should eventually be
   bound to an instance of the target object (as in gdbarch-tdep()),
   when such a thing exists.  */

/* This is set to the data address of the access causing the target
   to stop for a watchpoint.  */
static CORE_ADDR remote_watch_data_address;

/* This is non-zero if target stopped for a watchpoint.  */
static int remote_stopped_by_watchpoint_p;

static struct target_ops remote_ops;

static struct target_ops extended_remote_ops;

/* FIXME: cagney/1999-09-23: Even though getpkt was called with
   ``forever'' still use the normal timeout mechanism.  This is
   currently used by the ASYNC code to guarentee that target reads
   during the initial connect always time-out.  Once getpkt has been
   modified to return a timeout indication and, in turn
   remote_wait()/wait_for_inferior() have gained a timeout parameter
   this can go away.  */
static int wait_forever_enabled_p = 1;

/* Allow the user to specify what sequence to send to the remote
   when he requests a program interruption: Although ^C is usually
   what remote systems expect (this is the default, here), it is
   sometimes preferable to send a break.  On other systems such
   as the Linux kernel, a break followed by g, which is Magic SysRq g
   is required in order to interrupt the execution.  */
const char interrupt_sequence_control_c[] = "Ctrl-C";
const char interrupt_sequence_break[] = "BREAK";
const char interrupt_sequence_break_g[] = "BREAK-g";
static const char *const interrupt_sequence_modes[] =
  {
    interrupt_sequence_control_c,
    interrupt_sequence_break,
    interrupt_sequence_break_g,
    NULL
  };
static const char *interrupt_sequence_mode = interrupt_sequence_control_c;

static void
show_interrupt_sequence (struct ui_file *file, int from_tty,
			 struct cmd_list_element *c,
			 const char *value)
{
  if (interrupt_sequence_mode == interrupt_sequence_control_c)
    fprintf_filtered (file,
		      _("Send the ASCII ETX character (Ctrl-c) "
			"to the remote target to interrupt the "
			"execution of the program.\n"));
  else if (interrupt_sequence_mode == interrupt_sequence_break)
    fprintf_filtered (file,
		      _("send a break signal to the remote target "
			"to interrupt the execution of the program.\n"));
  else if (interrupt_sequence_mode == interrupt_sequence_break_g)
    fprintf_filtered (file,
		      _("Send a break signal and 'g' a.k.a. Magic SysRq g to "
			"the remote target to interrupt the execution "
			"of Linux kernel.\n"));
  else
    internal_error (__FILE__, __LINE__,
		    _("Invalid value for interrupt_sequence_mode: %s."),
		    interrupt_sequence_mode);
}

/* This boolean variable specifies whether interrupt_sequence is sent
   to the remote target when gdb connects to it.
   This is mostly needed when you debug the Linux kernel: The Linux kernel
   expects BREAK g which is Magic SysRq g for connecting gdb.  */
static int interrupt_on_connect = 0;

/* This variable is used to implement the "set/show remotebreak" commands.
   Since these commands are now deprecated in favor of "set/show remote
   interrupt-sequence", it no longer has any effect on the code.  */
static int remote_break;

static void
set_remotebreak (char *args, int from_tty, struct cmd_list_element *c)
{
  if (remote_break)
    interrupt_sequence_mode = interrupt_sequence_break;
  else
    interrupt_sequence_mode = interrupt_sequence_control_c;
}

static void
show_remotebreak (struct ui_file *file, int from_tty,
		  struct cmd_list_element *c,
		  const char *value)
{
}

/* Descriptor for I/O to remote machine.  Initialize it to NULL so that
   remote_open knows that we don't have a file open when the program
   starts.  */
static struct serial *remote_desc = NULL;

/* This variable sets the number of bits in an address that are to be
   sent in a memory ("M" or "m") packet.  Normally, after stripping
   leading zeros, the entire address would be sent.  This variable
   restricts the address to REMOTE_ADDRESS_SIZE bits.  HISTORY: The
   initial implementation of remote.c restricted the address sent in
   memory packets to ``host::sizeof long'' bytes - (typically 32
   bits).  Consequently, for 64 bit targets, the upper 32 bits of an
   address was never sent.  Since fixing this bug may cause a break in
   some remote targets this variable is principly provided to
   facilitate backward compatibility.  */

static int remote_address_size;

/* Temporary to track who currently owns the terminal.  See
   remote_terminal_* for more details.  */

static int remote_async_terminal_ours_p;

/* The executable file to use for "run" on the remote side.  */

static char *remote_exec_file = "";


/* User configurable variables for the number of characters in a
   memory read/write packet.  MIN (rsa->remote_packet_size,
   rsa->sizeof_g_packet) is the default.  Some targets need smaller
   values (fifo overruns, et.al.) and some users need larger values
   (speed up transfers).  The variables ``preferred_*'' (the user
   request), ``current_*'' (what was actually set) and ``forced_*''
   (Positive - a soft limit, negative - a hard limit).  */

struct memory_packet_config
{
  char *name;
  long size;
  int fixed_p;
};

/* Compute the current size of a read/write packet.  Since this makes
   use of ``actual_register_packet_size'' the computation is dynamic.  */

static long
get_memory_packet_size (struct memory_packet_config *config)
{
  struct remote_state *rs = get_remote_state ();
  struct remote_arch_state *rsa = get_remote_arch_state ();

  /* NOTE: The somewhat arbitrary 16k comes from the knowledge (folk
     law?) that some hosts don't cope very well with large alloca()
     calls.  Eventually the alloca() code will be replaced by calls to
     xmalloc() and make_cleanups() allowing this restriction to either
     be lifted or removed.  */
#ifndef MAX_REMOTE_PACKET_SIZE
#define MAX_REMOTE_PACKET_SIZE 16384
#endif
  /* NOTE: 20 ensures we can write at least one byte.  */
#ifndef MIN_REMOTE_PACKET_SIZE
#define MIN_REMOTE_PACKET_SIZE 20
#endif
  long what_they_get;
  if (config->fixed_p)
    {
      if (config->size <= 0)
	what_they_get = MAX_REMOTE_PACKET_SIZE;
      else
	what_they_get = config->size;
    }
  else
    {
      what_they_get = get_remote_packet_size ();
      /* Limit the packet to the size specified by the user.  */
      if (config->size > 0
	  && what_they_get > config->size)
	what_they_get = config->size;

      /* Limit it to the size of the targets ``g'' response unless we have
	 permission from the stub to use a larger packet size.  */
      if (rs->explicit_packet_size == 0
	  && rsa->actual_register_packet_size > 0
	  && what_they_get > rsa->actual_register_packet_size)
	what_they_get = rsa->actual_register_packet_size;
    }
  if (what_they_get > MAX_REMOTE_PACKET_SIZE)
    what_they_get = MAX_REMOTE_PACKET_SIZE;
  if (what_they_get < MIN_REMOTE_PACKET_SIZE)
    what_they_get = MIN_REMOTE_PACKET_SIZE;

  /* Make sure there is room in the global buffer for this packet
     (including its trailing NUL byte).  */
  if (rs->buf_size < what_they_get + 1)
    {
      rs->buf_size = 2 * what_they_get;
      rs->buf = xrealloc (rs->buf, 2 * what_they_get);
    }

  return what_they_get;
}

/* Update the size of a read/write packet.  If they user wants
   something really big then do a sanity check.  */

static void
set_memory_packet_size (char *args, struct memory_packet_config *config)
{
  int fixed_p = config->fixed_p;
  long size = config->size;

  if (args == NULL)
    error (_("Argument required (integer, `fixed' or `limited')."));
  else if (strcmp (args, "hard") == 0
      || strcmp (args, "fixed") == 0)
    fixed_p = 1;
  else if (strcmp (args, "soft") == 0
	   || strcmp (args, "limit") == 0)
    fixed_p = 0;
  else
    {
      char *end;

      size = strtoul (args, &end, 0);
      if (args == end)
	error (_("Invalid %s (bad syntax)."), config->name);
#if 0
      /* Instead of explicitly capping the size of a packet to
         MAX_REMOTE_PACKET_SIZE or dissallowing it, the user is
         instead allowed to set the size to something arbitrarily
         large.  */
      if (size > MAX_REMOTE_PACKET_SIZE)
	error (_("Invalid %s (too large)."), config->name);
#endif
    }
  /* Extra checks?  */
  if (fixed_p && !config->fixed_p)
    {
      if (! query (_("The target may not be able to correctly handle a %s\n"
		   "of %ld bytes. Change the packet size? "),
		   config->name, size))
	error (_("Packet size not changed."));
    }
  /* Update the config.  */
  config->fixed_p = fixed_p;
  config->size = size;
}

static void
show_memory_packet_size (struct memory_packet_config *config)
{
  printf_filtered (_("The %s is %ld. "), config->name, config->size);
  if (config->fixed_p)
    printf_filtered (_("Packets are fixed at %ld bytes.\n"),
		     get_memory_packet_size (config));
  else
    printf_filtered (_("Packets are limited to %ld bytes.\n"),
		     get_memory_packet_size (config));
}

static struct memory_packet_config memory_write_packet_config =
{
  "memory-write-packet-size",
};

static void
set_memory_write_packet_size (char *args, int from_tty)
{
  set_memory_packet_size (args, &memory_write_packet_config);
}

static void
show_memory_write_packet_size (char *args, int from_tty)
{
  show_memory_packet_size (&memory_write_packet_config);
}

static long
get_memory_write_packet_size (void)
{
  return get_memory_packet_size (&memory_write_packet_config);
}

static struct memory_packet_config memory_read_packet_config =
{
  "memory-read-packet-size",
};

static void
set_memory_read_packet_size (char *args, int from_tty)
{
  set_memory_packet_size (args, &memory_read_packet_config);
}

static void
show_memory_read_packet_size (char *args, int from_tty)
{
  show_memory_packet_size (&memory_read_packet_config);
}

static long
get_memory_read_packet_size (void)
{
  long size = get_memory_packet_size (&memory_read_packet_config);

  /* FIXME: cagney/1999-11-07: Functions like getpkt() need to get an
     extra buffer size argument before the memory read size can be
     increased beyond this.  */
  if (size > get_remote_packet_size ())
    size = get_remote_packet_size ();
  return size;
}


/* Generic configuration support for packets the stub optionally
   supports.  Allows the user to specify the use of the packet as well
   as allowing GDB to auto-detect support in the remote stub.  */

enum packet_support
  {
    PACKET_SUPPORT_UNKNOWN = 0,
    PACKET_ENABLE,
    PACKET_DISABLE
  };

struct packet_config
  {
    const char *name;
    const char *title;
    enum auto_boolean detect;
    enum packet_support support;
  };

/* Analyze a packet's return value and update the packet config
   accordingly.  */

enum packet_result
{
  PACKET_ERROR,
  PACKET_OK,
  PACKET_UNKNOWN
};

static void
update_packet_config (struct packet_config *config)
{
  switch (config->detect)
    {
    case AUTO_BOOLEAN_TRUE:
      config->support = PACKET_ENABLE;
      break;
    case AUTO_BOOLEAN_FALSE:
      config->support = PACKET_DISABLE;
      break;
    case AUTO_BOOLEAN_AUTO:
      config->support = PACKET_SUPPORT_UNKNOWN;
      break;
    }
}

static void
show_packet_config_cmd (struct packet_config *config)
{
  char *support = "internal-error";

  switch (config->support)
    {
    case PACKET_ENABLE:
      support = "enabled";
      break;
    case PACKET_DISABLE:
      support = "disabled";
      break;
    case PACKET_SUPPORT_UNKNOWN:
      support = "unknown";
      break;
    }
  switch (config->detect)
    {
    case AUTO_BOOLEAN_AUTO:
      printf_filtered (_("Support for the `%s' packet "
			 "is auto-detected, currently %s.\n"),
		       config->name, support);
      break;
    case AUTO_BOOLEAN_TRUE:
    case AUTO_BOOLEAN_FALSE:
      printf_filtered (_("Support for the `%s' packet is currently %s.\n"),
		       config->name, support);
      break;
    }
}

static void
add_packet_config_cmd (struct packet_config *config, const char *name,
		       const char *title, int legacy)
{
  char *set_doc;
  char *show_doc;
  char *cmd_name;

  config->name = name;
  config->title = title;
  config->detect = AUTO_BOOLEAN_AUTO;
  config->support = PACKET_SUPPORT_UNKNOWN;
  set_doc = xstrprintf ("Set use of remote protocol `%s' (%s) packet",
			name, title);
  show_doc = xstrprintf ("Show current use of remote "
			 "protocol `%s' (%s) packet",
			 name, title);
  /* set/show TITLE-packet {auto,on,off} */
  cmd_name = xstrprintf ("%s-packet", title);
  add_setshow_auto_boolean_cmd (cmd_name, class_obscure,
				&config->detect, set_doc,
				show_doc, NULL, /* help_doc */
				set_remote_protocol_packet_cmd,
				show_remote_protocol_packet_cmd,
				&remote_set_cmdlist, &remote_show_cmdlist);
  /* The command code copies the documentation strings.  */
  xfree (set_doc);
  xfree (show_doc);
  /* set/show remote NAME-packet {auto,on,off} -- legacy.  */
  if (legacy)
    {
      char *legacy_name;

      legacy_name = xstrprintf ("%s-packet", name);
      add_alias_cmd (legacy_name, cmd_name, class_obscure, 0,
		     &remote_set_cmdlist);
      add_alias_cmd (legacy_name, cmd_name, class_obscure, 0,
		     &remote_show_cmdlist);
    }
}

static enum packet_result
packet_check_result (const char *buf)
{
  if (buf[0] != '\0')
    {
      /* The stub recognized the packet request.  Check that the
	 operation succeeded.  */
      if (buf[0] == 'E'
	  && isxdigit (buf[1]) && isxdigit (buf[2])
	  && buf[3] == '\0')
	/* "Enn"  - definitly an error.  */
	return PACKET_ERROR;

      /* Always treat "E." as an error.  This will be used for
	 more verbose error messages, such as E.memtypes.  */
      if (buf[0] == 'E' && buf[1] == '.')
	return PACKET_ERROR;

      /* The packet may or may not be OK.  Just assume it is.  */
      return PACKET_OK;
    }
  else
    /* The stub does not support the packet.  */
    return PACKET_UNKNOWN;
}

static enum packet_result
packet_ok (const char *buf, struct packet_config *config)
{
  enum packet_result result;

  result = packet_check_result (buf);
  switch (result)
    {
    case PACKET_OK:
    case PACKET_ERROR:
      /* The stub recognized the packet request.  */
      switch (config->support)
	{
	case PACKET_SUPPORT_UNKNOWN:
	  if (remote_debug)
	    fprintf_unfiltered (gdb_stdlog,
				    "Packet %s (%s) is supported\n",
				    config->name, config->title);
	  config->support = PACKET_ENABLE;
	  break;
	case PACKET_DISABLE:
	  internal_error (__FILE__, __LINE__,
			  _("packet_ok: attempt to use a disabled packet"));
	  break;
	case PACKET_ENABLE:
	  break;
	}
      break;
    case PACKET_UNKNOWN:
      /* The stub does not support the packet.  */
      switch (config->support)
	{
	case PACKET_ENABLE:
	  if (config->detect == AUTO_BOOLEAN_AUTO)
	    /* If the stub previously indicated that the packet was
	       supported then there is a protocol error..  */
	    error (_("Protocol error: %s (%s) conflicting enabled responses."),
		   config->name, config->title);
	  else
	    /* The user set it wrong.  */
	    error (_("Enabled packet %s (%s) not recognized by stub"),
		   config->name, config->title);
	  break;
	case PACKET_SUPPORT_UNKNOWN:
	  if (remote_debug)
	    fprintf_unfiltered (gdb_stdlog,
				"Packet %s (%s) is NOT supported\n",
				config->name, config->title);
	  config->support = PACKET_DISABLE;
	  break;
	case PACKET_DISABLE:
	  break;
	}
      break;
    }

  return result;
}

enum {
  PACKET_vCont = 0,
  PACKET_X,
  PACKET_qSymbol,
  PACKET_P,
  PACKET_p,
  PACKET_Z0,
  PACKET_Z1,
  PACKET_Z2,
  PACKET_Z3,
  PACKET_Z4,
  PACKET_vFile_open,
  PACKET_vFile_pread,
  PACKET_vFile_pwrite,
  PACKET_vFile_close,
  PACKET_vFile_unlink,
  PACKET_vFile_readlink,
  PACKET_qXfer_auxv,
  PACKET_qXfer_features,
  PACKET_qXfer_libraries,
  PACKET_qXfer_libraries_svr4,
  PACKET_qXfer_memory_map,
  PACKET_qXfer_spu_read,
  PACKET_qXfer_spu_write,
  PACKET_qXfer_osdata,
  PACKET_qXfer_threads,
  PACKET_qXfer_statictrace_read,
  PACKET_qXfer_traceframe_info,
  PACKET_qXfer_uib,
  PACKET_qGetTIBAddr,
  PACKET_qGetTLSAddr,
  PACKET_qSupported,
  PACKET_QPassSignals,
  PACKET_QProgramSignals,
  PACKET_qSearch_memory,
  PACKET_vAttach,
  PACKET_vRun,
  PACKET_QStartNoAckMode,
  PACKET_vKill,
  PACKET_qXfer_siginfo_read,
  PACKET_qXfer_siginfo_write,
  PACKET_qAttached,
  PACKET_ConditionalTracepoints,
  PACKET_ConditionalBreakpoints,
  PACKET_BreakpointCommands,
  PACKET_FastTracepoints,
  PACKET_StaticTracepoints,
  PACKET_InstallInTrace,
  PACKET_bc,
  PACKET_bs,
  PACKET_TracepointSource,
  PACKET_QAllow,
  PACKET_qXfer_fdpic,
  PACKET_QDisableRandomization,
  PACKET_QAgent,
  PACKET_MAX
};

static struct packet_config remote_protocol_packets[PACKET_MAX];

static void
set_remote_protocol_packet_cmd (char *args, int from_tty,
				struct cmd_list_element *c)
{
  struct packet_config *packet;

  for (packet = remote_protocol_packets;
       packet < &remote_protocol_packets[PACKET_MAX];
       packet++)
    {
      if (&packet->detect == c->var)
	{
	  update_packet_config (packet);
	  return;
	}
    }
  internal_error (__FILE__, __LINE__, _("Could not find config for %s"),
		  c->name);
}

static void
show_remote_protocol_packet_cmd (struct ui_file *file, int from_tty,
				 struct cmd_list_element *c,
				 const char *value)
{
  struct packet_config *packet;

  for (packet = remote_protocol_packets;
       packet < &remote_protocol_packets[PACKET_MAX];
       packet++)
    {
      if (&packet->detect == c->var)
	{
	  show_packet_config_cmd (packet);
	  return;
	}
    }
  internal_error (__FILE__, __LINE__, _("Could not find config for %s"),
		  c->name);
}

/* Should we try one of the 'Z' requests?  */

enum Z_packet_type
{
  Z_PACKET_SOFTWARE_BP,
  Z_PACKET_HARDWARE_BP,
  Z_PACKET_WRITE_WP,
  Z_PACKET_READ_WP,
  Z_PACKET_ACCESS_WP,
  NR_Z_PACKET_TYPES
};

/* For compatibility with older distributions.  Provide a ``set remote
   Z-packet ...'' command that updates all the Z packet types.  */

static enum auto_boolean remote_Z_packet_detect;

static void
set_remote_protocol_Z_packet_cmd (char *args, int from_tty,
				  struct cmd_list_element *c)
{
  int i;

  for (i = 0; i < NR_Z_PACKET_TYPES; i++)
    {
      remote_protocol_packets[PACKET_Z0 + i].detect = remote_Z_packet_detect;
      update_packet_config (&remote_protocol_packets[PACKET_Z0 + i]);
    }
}

static void
show_remote_protocol_Z_packet_cmd (struct ui_file *file, int from_tty,
				   struct cmd_list_element *c,
				   const char *value)
{
  int i;

  for (i = 0; i < NR_Z_PACKET_TYPES; i++)
    {
      show_packet_config_cmd (&remote_protocol_packets[PACKET_Z0 + i]);
    }
}

/* Should we try the 'ThreadInfo' query packet?

   This variable (NOT available to the user: auto-detect only!)
   determines whether GDB will use the new, simpler "ThreadInfo"
   query or the older, more complex syntax for thread queries.
   This is an auto-detect variable (set to true at each connect,
   and set to false when the target fails to recognize it).  */

static int use_threadinfo_query;
static int use_threadextra_query;

/* Tokens for use by the asynchronous signal handlers for SIGINT.  */
static struct async_signal_handler *sigint_remote_twice_token;
static struct async_signal_handler *sigint_remote_token;


/* Asynchronous signal handle registered as event loop source for
   when we have pending events ready to be passed to the core.  */

static struct async_event_handler *remote_async_inferior_event_token;

/* Asynchronous signal handle registered as event loop source for when
   the remote sent us a %Stop notification.  The registered callback
   will do a vStopped sequence to pull the rest of the events out of
   the remote side into our event queue.  */

static struct async_event_handler *remote_async_get_pending_events_token;


static ptid_t magic_null_ptid;
static ptid_t not_sent_ptid;
static ptid_t any_thread_ptid;

/* These are the threads which we last sent to the remote system.  The
   TID member will be -1 for all or -2 for not sent yet.  */

static ptid_t general_thread;
static ptid_t continue_thread;

/* This the traceframe which we last selected on the remote system.
   It will be -1 if no traceframe is selected.  */
static int remote_traceframe_number = -1;

/* Find out if the stub attached to PID (and hence GDB should offer to
   detach instead of killing it when bailing out).  */

static int
remote_query_attached (int pid)
{
  struct remote_state *rs = get_remote_state ();
  size_t size = get_remote_packet_size ();

  if (remote_protocol_packets[PACKET_qAttached].support == PACKET_DISABLE)
    return 0;

  if (remote_multi_process_p (rs))
    xsnprintf (rs->buf, size, "qAttached:%x", pid);
  else
    xsnprintf (rs->buf, size, "qAttached");

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  switch (packet_ok (rs->buf,
		     &remote_protocol_packets[PACKET_qAttached]))
    {
    case PACKET_OK:
      if (strcmp (rs->buf, "1") == 0)
	return 1;
      break;
    case PACKET_ERROR:
      warning (_("Remote failure reply: %s"), rs->buf);
      break;
    case PACKET_UNKNOWN:
      break;
    }

  return 0;
}

/* Add PID to GDB's inferior table.  If FAKE_PID_P is true, then PID
   has been invented by GDB, instead of reported by the target.  Since
   we can be connected to a remote system before before knowing about
   any inferior, mark the target with execution when we find the first
   inferior.  If ATTACHED is 1, then we had just attached to this
   inferior.  If it is 0, then we just created this inferior.  If it
   is -1, then try querying the remote stub to find out if it had
   attached to the inferior or not.  */

static struct inferior *
remote_add_inferior (int fake_pid_p, int pid, int attached)
{
  struct inferior *inf;

  /* Check whether this process we're learning about is to be
     considered attached, or if is to be considered to have been
     spawned by the stub.  */
  if (attached == -1)
    attached = remote_query_attached (pid);

  if (gdbarch_has_global_solist (target_gdbarch))
    {
      /* If the target shares code across all inferiors, then every
	 attach adds a new inferior.  */
      inf = add_inferior (pid);

      /* ... and every inferior is bound to the same program space.
	 However, each inferior may still have its own address
	 space.  */
      inf->aspace = maybe_new_address_space ();
      inf->pspace = current_program_space;
    }
  else
    {
      /* In the traditional debugging scenario, there's a 1-1 match
	 between program/address spaces.  We simply bind the inferior
	 to the program space's address space.  */
      inf = current_inferior ();
      inferior_appeared (inf, pid);
    }

  inf->attach_flag = attached;
  inf->fake_pid_p = fake_pid_p;

  return inf;
}

/* Add thread PTID to GDB's thread list.  Tag it as executing/running
   according to RUNNING.  */

static void
remote_add_thread (ptid_t ptid, int running)
{
  add_thread (ptid);

  set_executing (ptid, running);
  set_running (ptid, running);
}

/* Come here when we learn about a thread id from the remote target.
   It may be the first time we hear about such thread, so take the
   opportunity to add it to GDB's thread list.  In case this is the
   first time we're noticing its corresponding inferior, add it to
   GDB's inferior list as well.  */

static void
remote_notice_new_inferior (ptid_t currthread, int running)
{
  /* If this is a new thread, add it to GDB's thread list.
     If we leave it up to WFI to do this, bad things will happen.  */

  if (in_thread_list (currthread) && is_exited (currthread))
    {
      /* We're seeing an event on a thread id we knew had exited.
	 This has to be a new thread reusing the old id.  Add it.  */
      remote_add_thread (currthread, running);
      return;
    }

  if (!in_thread_list (currthread))
    {
      struct inferior *inf = NULL;
      int pid = ptid_get_pid (currthread);

      if (ptid_is_pid (inferior_ptid)
	  && pid == ptid_get_pid (inferior_ptid))
	{
	  /* inferior_ptid has no thread member yet.  This can happen
	     with the vAttach -> remote_wait,"TAAthread:" path if the
	     stub doesn't support qC.  This is the first stop reported
	     after an attach, so this is the main thread.  Update the
	     ptid in the thread list.  */
	  if (in_thread_list (pid_to_ptid (pid)))
	    thread_change_ptid (inferior_ptid, currthread);
	  else
	    {
	      remote_add_thread (currthread, running);
	      inferior_ptid = currthread;
	    }
	  return;
	}

      if (ptid_equal (magic_null_ptid, inferior_ptid))
	{
	  /* inferior_ptid is not set yet.  This can happen with the
	     vRun -> remote_wait,"TAAthread:" path if the stub
	     doesn't support qC.  This is the first stop reported
	     after an attach, so this is the main thread.  Update the
	     ptid in the thread list.  */
	  thread_change_ptid (inferior_ptid, currthread);
	  return;
	}

      /* When connecting to a target remote, or to a target
	 extended-remote which already was debugging an inferior, we
	 may not know about it yet.  Add it before adding its child
	 thread, so notifications are emitted in a sensible order.  */
      if (!in_inferior_list (ptid_get_pid (currthread)))
	{
	  struct remote_state *rs = get_remote_state ();
	  int fake_pid_p = !remote_multi_process_p (rs);

	  inf = remote_add_inferior (fake_pid_p,
				     ptid_get_pid (currthread), -1);
	}

      /* This is really a new thread.  Add it.  */
      remote_add_thread (currthread, running);

      /* If we found a new inferior, let the common code do whatever
	 it needs to with it (e.g., read shared libraries, insert
	 breakpoints).  */
      if (inf != NULL)
	notice_new_inferior (currthread, running, 0);
    }
}

/* Return the private thread data, creating it if necessary.  */

static struct private_thread_info *
demand_private_info (ptid_t ptid)
{
  struct thread_info *info = find_thread_ptid (ptid);

  gdb_assert (info);

  if (!info->private)
    {
      info->private = xmalloc (sizeof (*(info->private)));
      info->private_dtor = free_private_thread_info;
      info->private->core = -1;
      info->private->extra = 0;
    }

  return info->private;
}

/* Call this function as a result of
   1) A halt indication (T packet) containing a thread id
   2) A direct query of currthread
   3) Successful execution of set thread */

static void
record_currthread (ptid_t currthread)
{
  general_thread = currthread;
}

static char *last_pass_packet;

/* If 'QPassSignals' is supported, tell the remote stub what signals
   it can simply pass through to the inferior without reporting.  */

static void
remote_pass_signals (int numsigs, unsigned char *pass_signals)
{
  if (remote_protocol_packets[PACKET_QPassSignals].support != PACKET_DISABLE)
    {
      char *pass_packet, *p;
      int count = 0, i;

      gdb_assert (numsigs < 256);
      for (i = 0; i < numsigs; i++)
	{
	  if (pass_signals[i])
	    count++;
	}
      pass_packet = xmalloc (count * 3 + strlen ("QPassSignals:") + 1);
      strcpy (pass_packet, "QPassSignals:");
      p = pass_packet + strlen (pass_packet);
      for (i = 0; i < numsigs; i++)
	{
	  if (pass_signals[i])
	    {
	      if (i >= 16)
		*p++ = tohex (i >> 4);
	      *p++ = tohex (i & 15);
	      if (count)
		*p++ = ';';
	      else
		break;
	      count--;
	    }
	}
      *p = 0;
      if (!last_pass_packet || strcmp (last_pass_packet, pass_packet))
	{
	  struct remote_state *rs = get_remote_state ();
	  char *buf = rs->buf;

	  putpkt (pass_packet);
	  getpkt (&rs->buf, &rs->buf_size, 0);
	  packet_ok (buf, &remote_protocol_packets[PACKET_QPassSignals]);
	  if (last_pass_packet)
	    xfree (last_pass_packet);
	  last_pass_packet = pass_packet;
	}
      else
	xfree (pass_packet);
    }
}

/* The last QProgramSignals packet sent to the target.  We bypass
   sending a new program signals list down to the target if the new
   packet is exactly the same as the last we sent.  IOW, we only let
   the target know about program signals list changes.  */

static char *last_program_signals_packet;

/* If 'QProgramSignals' is supported, tell the remote stub what
   signals it should pass through to the inferior when detaching.  */

static void
remote_program_signals (int numsigs, unsigned char *signals)
{
  if (remote_protocol_packets[PACKET_QProgramSignals].support != PACKET_DISABLE)
    {
      char *packet, *p;
      int count = 0, i;

      gdb_assert (numsigs < 256);
      for (i = 0; i < numsigs; i++)
	{
	  if (signals[i])
	    count++;
	}
      packet = xmalloc (count * 3 + strlen ("QProgramSignals:") + 1);
      strcpy (packet, "QProgramSignals:");
      p = packet + strlen (packet);
      for (i = 0; i < numsigs; i++)
	{
	  if (signal_pass_state (i))
	    {
	      if (i >= 16)
		*p++ = tohex (i >> 4);
	      *p++ = tohex (i & 15);
	      if (count)
		*p++ = ';';
	      else
		break;
	      count--;
	    }
	}
      *p = 0;
      if (!last_program_signals_packet
	  || strcmp (last_program_signals_packet, packet) != 0)
	{
	  struct remote_state *rs = get_remote_state ();
	  char *buf = rs->buf;

	  putpkt (packet);
	  getpkt (&rs->buf, &rs->buf_size, 0);
	  packet_ok (buf, &remote_protocol_packets[PACKET_QProgramSignals]);
	  xfree (last_program_signals_packet);
	  last_program_signals_packet = packet;
	}
      else
	xfree (packet);
    }
}

/* If PTID is MAGIC_NULL_PTID, don't set any thread.  If PTID is
   MINUS_ONE_PTID, set the thread to -1, so the stub returns the
   thread.  If GEN is set, set the general thread, if not, then set
   the step/continue thread.  */
static void
set_thread (struct ptid ptid, int gen)
{
  struct remote_state *rs = get_remote_state ();
  ptid_t state = gen ? general_thread : continue_thread;
  char *buf = rs->buf;
  char *endbuf = rs->buf + get_remote_packet_size ();

  if (ptid_equal (state, ptid))
    return;

  *buf++ = 'H';
  *buf++ = gen ? 'g' : 'c';
  if (ptid_equal (ptid, magic_null_ptid))
    xsnprintf (buf, endbuf - buf, "0");
  else if (ptid_equal (ptid, any_thread_ptid))
    xsnprintf (buf, endbuf - buf, "0");
  else if (ptid_equal (ptid, minus_one_ptid))
    xsnprintf (buf, endbuf - buf, "-1");
  else
    write_ptid (buf, endbuf, ptid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (gen)
    general_thread = ptid;
  else
    continue_thread = ptid;
}

static void
set_general_thread (struct ptid ptid)
{
  set_thread (ptid, 1);
}

static void
set_continue_thread (struct ptid ptid)
{
  set_thread (ptid, 0);
}

/* Change the remote current process.  Which thread within the process
   ends up selected isn't important, as long as it is the same process
   as what INFERIOR_PTID points to.

   This comes from that fact that there is no explicit notion of
   "selected process" in the protocol.  The selected process for
   general operations is the process the selected general thread
   belongs to.  */

static void
set_general_process (void)
{
  struct remote_state *rs = get_remote_state ();

  /* If the remote can't handle multiple processes, don't bother.  */
  if (!rs->extended || !remote_multi_process_p (rs))
    return;

  /* We only need to change the remote current thread if it's pointing
     at some other process.  */
  if (ptid_get_pid (general_thread) != ptid_get_pid (inferior_ptid))
    set_general_thread (inferior_ptid);
}


/*  Return nonzero if the thread PTID is still alive on the remote
    system.  */

static int
remote_thread_alive (struct target_ops *ops, ptid_t ptid)
{
  struct remote_state *rs = get_remote_state ();
  char *p, *endp;

  if (ptid_equal (ptid, magic_null_ptid))
    /* The main thread is always alive.  */
    return 1;

  if (ptid_get_pid (ptid) != 0 && ptid_get_tid (ptid) == 0)
    /* The main thread is always alive.  This can happen after a
       vAttach, if the remote side doesn't support
       multi-threading.  */
    return 1;

  p = rs->buf;
  endp = rs->buf + get_remote_packet_size ();

  *p++ = 'T';
  write_ptid (p, endp, ptid);

  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  return (rs->buf[0] == 'O' && rs->buf[1] == 'K');
}

/* About these extended threadlist and threadinfo packets.  They are
   variable length packets but, the fields within them are often fixed
   length.  They are redundent enough to send over UDP as is the
   remote protocol in general.  There is a matching unit test module
   in libstub.  */

#define OPAQUETHREADBYTES 8

/* a 64 bit opaque identifier */
typedef unsigned char threadref[OPAQUETHREADBYTES];

/* WARNING: This threadref data structure comes from the remote O.S.,
   libstub protocol encoding, and remote.c.  It is not particularly
   changable.  */

/* Right now, the internal structure is int. We want it to be bigger.
   Plan to fix this.  */

typedef int gdb_threadref;	/* Internal GDB thread reference.  */

/* gdb_ext_thread_info is an internal GDB data structure which is
   equivalent to the reply of the remote threadinfo packet.  */

struct gdb_ext_thread_info
  {
    threadref threadid;		/* External form of thread reference.  */
    int active;			/* Has state interesting to GDB?
				   regs, stack.  */
    char display[256];		/* Brief state display, name,
				   blocked/suspended.  */
    char shortname[32];		/* To be used to name threads.  */
    char more_display[256];	/* Long info, statistics, queue depth,
				   whatever.  */
  };

/* The volume of remote transfers can be limited by submitting
   a mask containing bits specifying the desired information.
   Use a union of these values as the 'selection' parameter to
   get_thread_info.  FIXME: Make these TAG names more thread specific.  */

#define TAG_THREADID 1
#define TAG_EXISTS 2
#define TAG_DISPLAY 4
#define TAG_THREADNAME 8
#define TAG_MOREDISPLAY 16

#define BUF_THREAD_ID_SIZE (OPAQUETHREADBYTES * 2)

char *unpack_varlen_hex (char *buff, ULONGEST *result);

static char *unpack_nibble (char *buf, int *val);

static char *pack_nibble (char *buf, int nibble);

static char *pack_hex_byte (char *pkt, int /* unsigned char */ byte);

static char *unpack_byte (char *buf, int *value);

static char *pack_int (char *buf, int value);

static char *unpack_int (char *buf, int *value);

static char *unpack_string (char *src, char *dest, int length);

static char *pack_threadid (char *pkt, threadref *id);

static char *unpack_threadid (char *inbuf, threadref *id);

void int_to_threadref (threadref *id, int value);

static int threadref_to_int (threadref *ref);

static void copy_threadref (threadref *dest, threadref *src);

static int threadmatch (threadref *dest, threadref *src);

static char *pack_threadinfo_request (char *pkt, int mode,
				      threadref *id);

static int remote_unpack_thread_info_response (char *pkt,
					       threadref *expectedref,
					       struct gdb_ext_thread_info
					       *info);


static int remote_get_threadinfo (threadref *threadid,
				  int fieldset,	/*TAG mask */
				  struct gdb_ext_thread_info *info);

static char *pack_threadlist_request (char *pkt, int startflag,
				      int threadcount,
				      threadref *nextthread);

static int parse_threadlist_response (char *pkt,
				      int result_limit,
				      threadref *original_echo,
				      threadref *resultlist,
				      int *doneflag);

static int remote_get_threadlist (int startflag,
				  threadref *nextthread,
				  int result_limit,
				  int *done,
				  int *result_count,
				  threadref *threadlist);

typedef int (*rmt_thread_action) (threadref *ref, void *context);

static int remote_threadlist_iterator (rmt_thread_action stepfunction,
				       void *context, int looplimit);

static int remote_newthread_step (threadref *ref, void *context);


/* Write a PTID to BUF.  ENDBUF points to one-passed-the-end of the
   buffer we're allowed to write to.  Returns
   BUF+CHARACTERS_WRITTEN.  */

static char *
write_ptid (char *buf, const char *endbuf, ptid_t ptid)
{
  int pid, tid;
  struct remote_state *rs = get_remote_state ();

  if (remote_multi_process_p (rs))
    {
      pid = ptid_get_pid (ptid);
      if (pid < 0)
	buf += xsnprintf (buf, endbuf - buf, "p-%x.", -pid);
      else
	buf += xsnprintf (buf, endbuf - buf, "p%x.", pid);
    }
  tid = ptid_get_tid (ptid);
  if (tid < 0)
    buf += xsnprintf (buf, endbuf - buf, "-%x", -tid);
  else
    buf += xsnprintf (buf, endbuf - buf, "%x", tid);

  return buf;
}

/* Extract a PTID from BUF.  If non-null, OBUF is set to the to one
   passed the last parsed char.  Returns null_ptid on error.  */

static ptid_t
read_ptid (char *buf, char **obuf)
{
  char *p = buf;
  char *pp;
  ULONGEST pid = 0, tid = 0;

  if (*p == 'p')
    {
      /* Multi-process ptid.  */
      pp = unpack_varlen_hex (p + 1, &pid);
      if (*pp != '.')
	error (_("invalid remote ptid: %s"), p);

      p = pp;
      pp = unpack_varlen_hex (p + 1, &tid);
      if (obuf)
	*obuf = pp;
      return ptid_build (pid, 0, tid);
    }

  /* No multi-process.  Just a tid.  */
  pp = unpack_varlen_hex (p, &tid);

  /* Since the stub is not sending a process id, then default to
     what's in inferior_ptid, unless it's null at this point.  If so,
     then since there's no way to know the pid of the reported
     threads, use the magic number.  */
  if (ptid_equal (inferior_ptid, null_ptid))
    pid = ptid_get_pid (magic_null_ptid);
  else
    pid = ptid_get_pid (inferior_ptid);

  if (obuf)
    *obuf = pp;
  return ptid_build (pid, 0, tid);
}

/* Encode 64 bits in 16 chars of hex.  */

static const char hexchars[] = "0123456789abcdef";

static int
ishex (int ch, int *val)
{
  if ((ch >= 'a') && (ch <= 'f'))
    {
      *val = ch - 'a' + 10;
      return 1;
    }
  if ((ch >= 'A') && (ch <= 'F'))
    {
      *val = ch - 'A' + 10;
      return 1;
    }
  if ((ch >= '0') && (ch <= '9'))
    {
      *val = ch - '0';
      return 1;
    }
  return 0;
}

static int
stubhex (int ch)
{
  if (ch >= 'a' && ch <= 'f')
    return ch - 'a' + 10;
  if (ch >= '0' && ch <= '9')
    return ch - '0';
  if (ch >= 'A' && ch <= 'F')
    return ch - 'A' + 10;
  return -1;
}

static int
stub_unpack_int (char *buff, int fieldlength)
{
  int nibble;
  int retval = 0;

  while (fieldlength)
    {
      nibble = stubhex (*buff++);
      retval |= nibble;
      fieldlength--;
      if (fieldlength)
	retval = retval << 4;
    }
  return retval;
}

char *
unpack_varlen_hex (char *buff,	/* packet to parse */
		   ULONGEST *result)
{
  int nibble;
  ULONGEST retval = 0;

  while (ishex (*buff, &nibble))
    {
      buff++;
      retval = retval << 4;
      retval |= nibble & 0x0f;
    }
  *result = retval;
  return buff;
}

static char *
unpack_nibble (char *buf, int *val)
{
  *val = fromhex (*buf++);
  return buf;
}

static char *
pack_nibble (char *buf, int nibble)
{
  *buf++ = hexchars[(nibble & 0x0f)];
  return buf;
}

static char *
pack_hex_byte (char *pkt, int byte)
{
  *pkt++ = hexchars[(byte >> 4) & 0xf];
  *pkt++ = hexchars[(byte & 0xf)];
  return pkt;
}

static char *
unpack_byte (char *buf, int *value)
{
  *value = stub_unpack_int (buf, 2);
  return buf + 2;
}

static char *
pack_int (char *buf, int value)
{
  buf = pack_hex_byte (buf, (value >> 24) & 0xff);
  buf = pack_hex_byte (buf, (value >> 16) & 0xff);
  buf = pack_hex_byte (buf, (value >> 8) & 0x0ff);
  buf = pack_hex_byte (buf, (value & 0xff));
  return buf;
}

static char *
unpack_int (char *buf, int *value)
{
  *value = stub_unpack_int (buf, 8);
  return buf + 8;
}

#if 0			/* Currently unused, uncomment when needed.  */
static char *pack_string (char *pkt, char *string);

static char *
pack_string (char *pkt, char *string)
{
  char ch;
  int len;

  len = strlen (string);
  if (len > 200)
    len = 200;		/* Bigger than most GDB packets, junk???  */
  pkt = pack_hex_byte (pkt, len);
  while (len-- > 0)
    {
      ch = *string++;
      if ((ch == '\0') || (ch == '#'))
	ch = '*';		/* Protect encapsulation.  */
      *pkt++ = ch;
    }
  return pkt;
}
#endif /* 0 (unused) */

static char *
unpack_string (char *src, char *dest, int length)
{
  while (length--)
    *dest++ = *src++;
  *dest = '\0';
  return src;
}

static char *
pack_threadid (char *pkt, threadref *id)
{
  char *limit;
  unsigned char *altid;

  altid = (unsigned char *) id;
  limit = pkt + BUF_THREAD_ID_SIZE;
  while (pkt < limit)
    pkt = pack_hex_byte (pkt, *altid++);
  return pkt;
}


static char *
unpack_threadid (char *inbuf, threadref *id)
{
  char *altref;
  char *limit = inbuf + BUF_THREAD_ID_SIZE;
  int x, y;

  altref = (char *) id;

  while (inbuf < limit)
    {
      x = stubhex (*inbuf++);
      y = stubhex (*inbuf++);
      *altref++ = (x << 4) | y;
    }
  return inbuf;
}

/* Externally, threadrefs are 64 bits but internally, they are still
   ints.  This is due to a mismatch of specifications.  We would like
   to use 64bit thread references internally.  This is an adapter
   function.  */

void
int_to_threadref (threadref *id, int value)
{
  unsigned char *scan;

  scan = (unsigned char *) id;
  {
    int i = 4;
    while (i--)
      *scan++ = 0;
  }
  *scan++ = (value >> 24) & 0xff;
  *scan++ = (value >> 16) & 0xff;
  *scan++ = (value >> 8) & 0xff;
  *scan++ = (value & 0xff);
}

static int
threadref_to_int (threadref *ref)
{
  int i, value = 0;
  unsigned char *scan;

  scan = *ref;
  scan += 4;
  i = 4;
  while (i-- > 0)
    value = (value << 8) | ((*scan++) & 0xff);
  return value;
}

static void
copy_threadref (threadref *dest, threadref *src)
{
  int i;
  unsigned char *csrc, *cdest;

  csrc = (unsigned char *) src;
  cdest = (unsigned char *) dest;
  i = 8;
  while (i--)
    *cdest++ = *csrc++;
}

static int
threadmatch (threadref *dest, threadref *src)
{
  /* Things are broken right now, so just assume we got a match.  */
#if 0
  unsigned char *srcp, *destp;
  int i, result;
  srcp = (char *) src;
  destp = (char *) dest;

  result = 1;
  while (i-- > 0)
    result &= (*srcp++ == *destp++) ? 1 : 0;
  return result;
#endif
  return 1;
}

/*
   threadid:1,        # always request threadid
   context_exists:2,
   display:4,
   unique_name:8,
   more_display:16
 */

/* Encoding:  'Q':8,'P':8,mask:32,threadid:64 */

static char *
pack_threadinfo_request (char *pkt, int mode, threadref *id)
{
  *pkt++ = 'q';				/* Info Query */
  *pkt++ = 'P';				/* process or thread info */
  pkt = pack_int (pkt, mode);		/* mode */
  pkt = pack_threadid (pkt, id);	/* threadid */
  *pkt = '\0';				/* terminate */
  return pkt;
}

/* These values tag the fields in a thread info response packet.  */
/* Tagging the fields allows us to request specific fields and to
   add more fields as time goes by.  */

#define TAG_THREADID 1		/* Echo the thread identifier.  */
#define TAG_EXISTS 2		/* Is this process defined enough to
				   fetch registers and its stack?  */
#define TAG_DISPLAY 4		/* A short thing maybe to put on a window */
#define TAG_THREADNAME 8	/* string, maps 1-to-1 with a thread is.  */
#define TAG_MOREDISPLAY 16	/* Whatever the kernel wants to say about
				   the process.  */

static int
remote_unpack_thread_info_response (char *pkt, threadref *expectedref,
				    struct gdb_ext_thread_info *info)
{
  struct remote_state *rs = get_remote_state ();
  int mask, length;
  int tag;
  threadref ref;
  char *limit = pkt + rs->buf_size; /* Plausible parsing limit.  */
  int retval = 1;

  /* info->threadid = 0; FIXME: implement zero_threadref.  */
  info->active = 0;
  info->display[0] = '\0';
  info->shortname[0] = '\0';
  info->more_display[0] = '\0';

  /* Assume the characters indicating the packet type have been
     stripped.  */
  pkt = unpack_int (pkt, &mask);	/* arg mask */
  pkt = unpack_threadid (pkt, &ref);

  if (mask == 0)
    warning (_("Incomplete response to threadinfo request."));
  if (!threadmatch (&ref, expectedref))
    {			/* This is an answer to a different request.  */
      warning (_("ERROR RMT Thread info mismatch."));
      return 0;
    }
  copy_threadref (&info->threadid, &ref);

  /* Loop on tagged fields , try to bail if somthing goes wrong.  */

  /* Packets are terminated with nulls.  */
  while ((pkt < limit) && mask && *pkt)
    {
      pkt = unpack_int (pkt, &tag);	/* tag */
      pkt = unpack_byte (pkt, &length);	/* length */
      if (!(tag & mask))		/* Tags out of synch with mask.  */
	{
	  warning (_("ERROR RMT: threadinfo tag mismatch."));
	  retval = 0;
	  break;
	}
      if (tag == TAG_THREADID)
	{
	  if (length != 16)
	    {
	      warning (_("ERROR RMT: length of threadid is not 16."));
	      retval = 0;
	      break;
	    }
	  pkt = unpack_threadid (pkt, &ref);
	  mask = mask & ~TAG_THREADID;
	  continue;
	}
      if (tag == TAG_EXISTS)
	{
	  info->active = stub_unpack_int (pkt, length);
	  pkt += length;
	  mask = mask & ~(TAG_EXISTS);
	  if (length > 8)
	    {
	      warning (_("ERROR RMT: 'exists' length too long."));
	      retval = 0;
	      break;
	    }
	  continue;
	}
      if (tag == TAG_THREADNAME)
	{
	  pkt = unpack_string (pkt, &info->shortname[0], length);
	  mask = mask & ~TAG_THREADNAME;
	  continue;
	}
      if (tag == TAG_DISPLAY)
	{
	  pkt = unpack_string (pkt, &info->display[0], length);
	  mask = mask & ~TAG_DISPLAY;
	  continue;
	}
      if (tag == TAG_MOREDISPLAY)
	{
	  pkt = unpack_string (pkt, &info->more_display[0], length);
	  mask = mask & ~TAG_MOREDISPLAY;
	  continue;
	}
      warning (_("ERROR RMT: unknown thread info tag."));
      break;			/* Not a tag we know about.  */
    }
  return retval;
}

static int
remote_get_threadinfo (threadref *threadid, int fieldset,	/* TAG mask */
		       struct gdb_ext_thread_info *info)
{
  struct remote_state *rs = get_remote_state ();
  int result;

  pack_threadinfo_request (rs->buf, fieldset, threadid);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (rs->buf[0] == '\0')
    return 0;

  result = remote_unpack_thread_info_response (rs->buf + 2,
					       threadid, info);
  return result;
}

/*    Format: i'Q':8,i"L":8,initflag:8,batchsize:16,lastthreadid:32   */

static char *
pack_threadlist_request (char *pkt, int startflag, int threadcount,
			 threadref *nextthread)
{
  *pkt++ = 'q';			/* info query packet */
  *pkt++ = 'L';			/* Process LIST or threadLIST request */
  pkt = pack_nibble (pkt, startflag);		/* initflag 1 bytes */
  pkt = pack_hex_byte (pkt, threadcount);	/* threadcount 2 bytes */
  pkt = pack_threadid (pkt, nextthread);	/* 64 bit thread identifier */
  *pkt = '\0';
  return pkt;
}

/* Encoding:   'q':8,'M':8,count:16,done:8,argthreadid:64,(threadid:64)* */

static int
parse_threadlist_response (char *pkt, int result_limit,
			   threadref *original_echo, threadref *resultlist,
			   int *doneflag)
{
  struct remote_state *rs = get_remote_state ();
  char *limit;
  int count, resultcount, done;

  resultcount = 0;
  /* Assume the 'q' and 'M chars have been stripped.  */
  limit = pkt + (rs->buf_size - BUF_THREAD_ID_SIZE);
  /* done parse past here */
  pkt = unpack_byte (pkt, &count);	/* count field */
  pkt = unpack_nibble (pkt, &done);
  /* The first threadid is the argument threadid.  */
  pkt = unpack_threadid (pkt, original_echo);	/* should match query packet */
  while ((count-- > 0) && (pkt < limit))
    {
      pkt = unpack_threadid (pkt, resultlist++);
      if (resultcount++ >= result_limit)
	break;
    }
  if (doneflag)
    *doneflag = done;
  return resultcount;
}

static int
remote_get_threadlist (int startflag, threadref *nextthread, int result_limit,
		       int *done, int *result_count, threadref *threadlist)
{
  struct remote_state *rs = get_remote_state ();
  static threadref echo_nextthread;
  int result = 1;

  /* Trancate result limit to be smaller than the packet size.  */
  if ((((result_limit + 1) * BUF_THREAD_ID_SIZE) + 10)
      >= get_remote_packet_size ())
    result_limit = (get_remote_packet_size () / BUF_THREAD_ID_SIZE) - 2;

  pack_threadlist_request (rs->buf, startflag, result_limit, nextthread);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);

  if (*rs->buf == '\0')
    return 0;
  else
    *result_count =
      parse_threadlist_response (rs->buf + 2, result_limit, &echo_nextthread,
                                 threadlist, done);

  if (!threadmatch (&echo_nextthread, nextthread))
    {
      /* FIXME: This is a good reason to drop the packet.  */
      /* Possably, there is a duplicate response.  */
      /* Possabilities :
         retransmit immediatly - race conditions
         retransmit after timeout - yes
         exit
         wait for packet, then exit
       */
      warning (_("HMM: threadlist did not echo arg thread, dropping it."));
      return 0;			/* I choose simply exiting.  */
    }
  if (*result_count <= 0)
    {
      if (*done != 1)
	{
	  warning (_("RMT ERROR : failed to get remote thread list."));
	  result = 0;
	}
      return result;		/* break; */
    }
  if (*result_count > result_limit)
    {
      *result_count = 0;
      warning (_("RMT ERROR: threadlist response longer than requested."));
      return 0;
    }
  return result;
}

/* This is the interface between remote and threads, remotes upper
   interface.  */

/* remote_find_new_threads retrieves the thread list and for each
   thread in the list, looks up the thread in GDB's internal list,
   adding the thread if it does not already exist.  This involves
   getting partial thread lists from the remote target so, polling the
   quit_flag is required.  */


/* About this many threadisds fit in a packet.  */

#define MAXTHREADLISTRESULTS 32

static int
remote_threadlist_iterator (rmt_thread_action stepfunction, void *context,
			    int looplimit)
{
  int done, i, result_count;
  int startflag = 1;
  int result = 1;
  int loopcount = 0;
  static threadref nextthread;
  static threadref resultthreadlist[MAXTHREADLISTRESULTS];

  done = 0;
  while (!done)
    {
      if (loopcount++ > looplimit)
	{
	  result = 0;
	  warning (_("Remote fetch threadlist -infinite loop-."));
	  break;
	}
      if (!remote_get_threadlist (startflag, &nextthread, MAXTHREADLISTRESULTS,
				  &done, &result_count, resultthreadlist))
	{
	  result = 0;
	  break;
	}
      /* Clear for later iterations.  */
      startflag = 0;
      /* Setup to resume next batch of thread references, set nextthread.  */
      if (result_count >= 1)
	copy_threadref (&nextthread, &resultthreadlist[result_count - 1]);
      i = 0;
      while (result_count--)
	if (!(result = (*stepfunction) (&resultthreadlist[i++], context)))
	  break;
    }
  return result;
}

static int
remote_newthread_step (threadref *ref, void *context)
{
  int pid = ptid_get_pid (inferior_ptid);
  ptid_t ptid = ptid_build (pid, 0, threadref_to_int (ref));

  if (!in_thread_list (ptid))
    add_thread (ptid);
  return 1;			/* continue iterator */
}

#define CRAZY_MAX_THREADS 1000

static ptid_t
remote_current_thread (ptid_t oldpid)
{
  struct remote_state *rs = get_remote_state ();

  putpkt ("qC");
  getpkt (&rs->buf, &rs->buf_size, 0);
  if (rs->buf[0] == 'Q' && rs->buf[1] == 'C')
    return read_ptid (&rs->buf[2], NULL);
  else
    return oldpid;
}

/* Find new threads for info threads command.
 * Original version, using John Metzler's thread protocol.
 */

static void
remote_find_new_threads (void)
{
  remote_threadlist_iterator (remote_newthread_step, 0,
			      CRAZY_MAX_THREADS);
}

#if defined(HAVE_LIBEXPAT)

typedef struct thread_item
{
  ptid_t ptid;
  char *extra;
  int core;
} thread_item_t;
DEF_VEC_O(thread_item_t);

struct threads_parsing_context
{
  VEC (thread_item_t) *items;
};

static void
start_thread (struct gdb_xml_parser *parser,
	      const struct gdb_xml_element *element,
	      void *user_data, VEC(gdb_xml_value_s) *attributes)
{
  struct threads_parsing_context *data = user_data;

  struct thread_item item;
  char *id;
  struct gdb_xml_value *attr;

  id = xml_find_attribute (attributes, "id")->value;
  item.ptid = read_ptid (id, NULL);

  attr = xml_find_attribute (attributes, "core");
  if (attr != NULL)
    item.core = *(ULONGEST *) attr->value;
  else
    item.core = -1;

  item.extra = 0;

  VEC_safe_push (thread_item_t, data->items, &item);
}

static void
end_thread (struct gdb_xml_parser *parser,
	    const struct gdb_xml_element *element,
	    void *user_data, const char *body_text)
{
  struct threads_parsing_context *data = user_data;

  if (body_text && *body_text)
    VEC_last (thread_item_t, data->items)->extra = xstrdup (body_text);
}

const struct gdb_xml_attribute thread_attributes[] = {
  { "id", GDB_XML_AF_NONE, NULL, NULL },
  { "core", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
  { NULL, GDB_XML_AF_NONE, NULL, NULL }
};

const struct gdb_xml_element thread_children[] = {
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

const struct gdb_xml_element threads_children[] = {
  { "thread", thread_attributes, thread_children,
    GDB_XML_EF_REPEATABLE | GDB_XML_EF_OPTIONAL,
    start_thread, end_thread },
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

const struct gdb_xml_element threads_elements[] = {
  { "threads", NULL, threads_children,
    GDB_XML_EF_NONE, NULL, NULL },
  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
};

/* Discard the contents of the constructed thread info context.  */

static void
clear_threads_parsing_context (void *p)
{
  struct threads_parsing_context *context = p;
  int i;
  struct thread_item *item;

  for (i = 0; VEC_iterate (thread_item_t, context->items, i, item); ++i)
    xfree (item->extra);

  VEC_free (thread_item_t, context->items);
}

#endif

/*
 * Find all threads for info threads command.
 * Uses new thread protocol contributed by Cisco.
 * Falls back and attempts to use the older method (above)
 * if the target doesn't respond to the new method.
 */

static void
remote_threads_info (struct target_ops *ops)
{
  struct remote_state *rs = get_remote_state ();
  char *bufp;
  ptid_t new_thread;

  if (remote_desc == 0)		/* paranoia */
    error (_("Command can only be used when connected to the remote target."));

#if defined(HAVE_LIBEXPAT)
  if (remote_protocol_packets[PACKET_qXfer_threads].support == PACKET_ENABLE)
    {
      char *xml = target_read_stralloc (&current_target,
					 TARGET_OBJECT_THREADS, NULL);

      struct cleanup *back_to = make_cleanup (xfree, xml);

      if (xml && *xml)
	{
	  struct threads_parsing_context context;

	  context.items = NULL;
	  make_cleanup (clear_threads_parsing_context, &context);

	  if (gdb_xml_parse_quick (_("threads"), "threads.dtd",
				   threads_elements, xml, &context) == 0)
	    {
	      int i;
	      struct thread_item *item;

	      for (i = 0;
		   VEC_iterate (thread_item_t, context.items, i, item);
		   ++i)
		{
		  if (!ptid_equal (item->ptid, null_ptid))
		    {
		      struct private_thread_info *info;
		      /* In non-stop mode, we assume new found threads
			 are running until proven otherwise with a
			 stop reply.  In all-stop, we can only get
			 here if all threads are stopped.  */
		      int running = non_stop ? 1 : 0;

		      remote_notice_new_inferior (item->ptid, running);

		      info = demand_private_info (item->ptid);
		      info->core = item->core;
		      info->extra = item->extra;
		      item->extra = NULL;
		    }
		}
	    }
	}

      do_cleanups (back_to);
      return;
    }
#endif

  if (use_threadinfo_query)
    {
      putpkt ("qfThreadInfo");
      getpkt (&rs->buf, &rs->buf_size, 0);
      bufp = rs->buf;
      if (bufp[0] != '\0')		/* q packet recognized */
	{
	  while (*bufp++ == 'm')	/* reply contains one or more TID */
	    {
	      do
		{
		  new_thread = read_ptid (bufp, &bufp);
		  if (!ptid_equal (new_thread, null_ptid))
		    {
		      /* In non-stop mode, we assume new found threads
			 are running until proven otherwise with a
			 stop reply.  In all-stop, we can only get
			 here if all threads are stopped.  */
		      int running = non_stop ? 1 : 0;

		      remote_notice_new_inferior (new_thread, running);
		    }
		}
	      while (*bufp++ == ',');	/* comma-separated list */
	      putpkt ("qsThreadInfo");
	      getpkt (&rs->buf, &rs->buf_size, 0);
	      bufp = rs->buf;
	    }
	  return;	/* done */
	}
    }

  /* Only qfThreadInfo is supported in non-stop mode.  */
  if (non_stop)
    return;

  /* Else fall back to old method based on jmetzler protocol.  */
  use_threadinfo_query = 0;
  remote_find_new_threads ();
  return;
}

/*
 * Collect a descriptive string about the given thread.
 * The target may say anything it wants to about the thread
 * (typically info about its blocked / runnable state, name, etc.).
 * This string will appear in the info threads display.
 *
 * Optional: targets are not required to implement this function.
 */

static char *
remote_threads_extra_info (struct thread_info *tp)
{
  struct remote_state *rs = get_remote_state ();
  int result;
  int set;
  threadref id;
  struct gdb_ext_thread_info threadinfo;
  static char display_buf[100];	/* arbitrary...  */
  int n = 0;                    /* position in display_buf */

  if (remote_desc == 0)		/* paranoia */
    internal_error (__FILE__, __LINE__,
		    _("remote_threads_extra_info"));

  if (ptid_equal (tp->ptid, magic_null_ptid)
      || (ptid_get_pid (tp->ptid) != 0 && ptid_get_tid (tp->ptid) == 0))
    /* This is the main thread which was added by GDB.  The remote
       server doesn't know about it.  */
    return NULL;

  if (remote_protocol_packets[PACKET_qXfer_threads].support == PACKET_ENABLE)
    {
      struct thread_info *info = find_thread_ptid (tp->ptid);

      if (info && info->private)
	return info->private->extra;
      else
	return NULL;
    }

  if (use_threadextra_query)
    {
      char *b = rs->buf;
      char *endb = rs->buf + get_remote_packet_size ();

      xsnprintf (b, endb - b, "qThreadExtraInfo,");
      b += strlen (b);
      write_ptid (b, endb, tp->ptid);

      putpkt (rs->buf);
      getpkt (&rs->buf, &rs->buf_size, 0);
      if (rs->buf[0] != 0)
	{
	  n = min (strlen (rs->buf) / 2, sizeof (display_buf));
	  result = hex2bin (rs->buf, (gdb_byte *) display_buf, n);
	  display_buf [result] = '\0';
	  return display_buf;
	}
    }

  /* If the above query fails, fall back to the old method.  */
  use_threadextra_query = 0;
  set = TAG_THREADID | TAG_EXISTS | TAG_THREADNAME
    | TAG_MOREDISPLAY | TAG_DISPLAY;
  int_to_threadref (&id, ptid_get_tid (tp->ptid));
  if (remote_get_threadinfo (&id, set, &threadinfo))
    if (threadinfo.active)
      {
	if (*threadinfo.shortname)
	  n += xsnprintf (&display_buf[0], sizeof (display_buf) - n,
			  " Name: %s,", threadinfo.shortname);
	if (*threadinfo.display)
	  n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
			  " State: %s,", threadinfo.display);
	if (*threadinfo.more_display)
	  n += xsnprintf (&display_buf[n], sizeof (display_buf) - n,
			  " Priority: %s", threadinfo.more_display);

	if (n > 0)
	  {
	    /* For purely cosmetic reasons, clear up trailing commas.  */
	    if (',' == display_buf[n-1])
	      display_buf[n-1] = ' ';
	    return display_buf;
	  }
      }
  return NULL;
}


static int
remote_static_tracepoint_marker_at (CORE_ADDR addr,
				    struct static_tracepoint_marker *marker)
{
  struct remote_state *rs = get_remote_state ();
  char *p = rs->buf;

  xsnprintf (p, get_remote_packet_size (), "qTSTMat:");
  p += strlen (p);
  p += hexnumstr (p, addr);
  putpkt (rs->buf);
  getpkt (&rs->buf, &rs->buf_size, 0);
  p = rs->buf;

  if (*p == 'E')
    error (_("Remote failure reply: %s"), p);

  if (*p++ == 'm')
    {
      parse_static_tracepoint_marker_definition (p, &p, marker);
      return 1;
    }

  return 0;
}

static VEC(static_tracepoint_marker_p) *
remote_static_tracepoint_markers_by_strid (const char *strid)
{
  struct remote_state *rs = get_remote_state ();
  VEC(static_tracepoint_marker_p) *markers = NULL;
  struct static_tracepoint_marker *marker = NULL;
  struct cleanup *old_chain;
  char *p;

  /* Ask for a first packet of static tracepoint marker
     definition.  */
  putpkt ("qTfSTM");
  getpkt (&rs->buf, &rs->buf_size, 0);
  p = rs->buf;
  if (*p == 'E')
    error (_("Remote failure reply: %s"), p);

  old_chain = make_cleanup (free_current_marker, &marker);

  while (*p++ == 'm')
    {
      if (marker == NULL)
	marker = XCNEW (struct static_tracepoint_marker);

      do
	{
	  parse_static_tracepoint_marker_definition (p, &p, marker);

	  if (strid == NULL || strcmp (strid, marker->str_id) == 0)
	    {
	      VEC_safe_push (static_tracepoint_marker_p,
			     markers, marker);
	      marker = NULL;
	    }
	  else
	    {
	      release_static_tracepoint_marker (marker);
	      memset (marker, 0, sizeof (*marker));
	    }
	}
      while (*p++ == ',');	/* comma-separated list */
      /* Ask for another packet of static tracepoint definition.  */
      putpkt ("qTsSTM");
      getpkt (&rs->buf, &rs->buf_size, 0);
      p = rs->buf;
    }

  do_cleanups (old_chain);
  return markers;
}


/* Implement the to_get_ada_task_ptid function for the remote targets.  */

static ptid_t
remote_get_ada_task_ptid (long lwp, long thread)
{
  return ptid_build (ptid_get_pid (inferior_ptid), 0, lwp);
}


/* Restart the remote side; this is an extended protocol operation.  */

static void
extended_remote_restart (void)
{
  struct remote_state *rs = get_remote_state ();

  /* Send the restart command; for reasons I don't understand the
     remote side really expects a number after the "R".  */
  xsnprintf (rs->buf, get_remote_packet_size (), "R%x", 0);
  putpkt (rs->buf);

  remote_fileio_reset ();
}

/* Clean up connection to a remote debugger.  */

static void
remote_close (int quitting)
{
  if (remote_desc == NULL)
    return; /* already closed */

  /* Make sure we leave stdin registered in the event loop, and we
     don't leave the async SIGINT signal handler installed.  */
  remote_terminal_ours ();

  serial_close (remote_desc);
  remote_desc = NULL;

  /* We don't have a connection to the remote stub anymore.  Get rid
     of all the inferiors and their threads we were controlling.
     Reset inferior_ptid to null_ptid first, as otherwise has_stack_frame
     will be unable to find the thread corresponding to (pid, 0, 0).  */
  inferior_ptid = null_ptid;
  discard_all_inferiors ();

  /* We're no longer interested in any of these events.  */
  discard_pending_stop_replies (-1);

  if (remote_async_inferior_event_token)
    delete_async_event_handler (&remote_async_inferior_event_token);
  if (remote_async_get_pending_events_token)
    delete_async_event_handler (&remote_async_get_pending_events_token);
}

/* Query the remote side for the text, data and bss offsets.  */

static void
get_offsets (void)
{
  struct remote_state *rs = get_remote_state ();
  char *buf;
  char *ptr;
  int lose, num_segments = 0, do_sections, do_segments;
  CORE_ADDR text_addr, data_addr, bss_addr, segments[2];
  struct section_offsets *offs;
  struct symfile_segment_data *data;

  if (symfile_objfile == NULL)
    return;

  putpkt ("qOffsets");
  getpkt (&rs->buf, &rs->buf_size, 0);
  buf = rs->buf;

  if (buf[0] == '\000')
    return;			/* Return silently.  Stub doesn't support
				   this command.  */
  if (buf[0] == 'E')
    {
      warning (_("Remote failure reply: %s"), buf);
      return;
    }

  /* Pick up each field in turn.  This used to be done with scanf, but
     scanf will make trouble if CORE_ADDR size doesn't match
     conversion directives correctly.  The following code will work
     with any size of CORE_ADDR.  */
  text_addr = data_addr = bss_addr = 0;
  ptr = buf;
  lose = 0;

  if (strncmp (ptr, "Text=", 5) == 0)
    {
      ptr += 5;
      /* Don't use strtol, could lose on big values.  */
      while (*ptr && *ptr != ';')
	text_addr = (text_addr << 4) + fromhex (*ptr++);

      if (strncmp (ptr, ";Data=", 6) == 0)
	{
	  ptr += 6;
	  while (*ptr && *ptr != ';')
	    data_addr = (data_addr << 4) + fromhex (*ptr++);
	}
      else
	lose = 1;

      if (!lose && strncmp (ptr, ";Bss=", 5) == 0)
	{
	  ptr += 5;
	  while (*ptr && *ptr != ';')
	    bss_addr = (bss_addr << 4) + fromhex (*ptr++);

	  if (bss_addr != data_addr)
	    warning (_("Target reported unsupported offsets: %s"), buf);
	}
      else
	lose = 1;
    }
  else if (strncmp (ptr, "TextSeg=", 8) == 0)
    {
      ptr += 8;
      /* Don't use strtol, could lose on big values.  */
      while (*ptr && *ptr != ';')
	text_addr = (text_addr << 4) + fromhex (*ptr++);
      num_segments = 1;

      if (strncmp (ptr, ";DataSeg=", 9) == 0)
	{
	  ptr += 9;
	  while (*ptr && *ptr != ';')
	    data_addr = (data_addr << 4) + fromhex (*ptr++);
	  num_segments++;
	}
    }
  else
    lose = 1;

  if (lose)
    error (_("Malformed response to offset query, %s"), buf);
  else if (*ptr != '\0')
    warning (_("Target reported unsupported offsets: %s"), buf);

  offs = ((struct section_offsets *)
	  alloca (SIZEOF_N_SECTION_OFFSETS (symfile_objfile->num_sections)));
  memcpy (offs, symfile_objfile->section_offsets,
	  SIZEOF_N_SECTION_OFFSETS (symfile_objfile->num_sections));

  data = get_symfile_segment_data (symfile_objfile->obfd);
  do_segments = (data != NULL);
  do_sections = num_segments == 0;

  if (num_segments > 0)
    {
      segments[0] = text_addr;
      segments[1] = data_addr;
    }
  /* If we have two segments, we can still try to relocate everything
     by assuming that the .text and .data offsets apply to the whole
     text and data segments.  Convert the offsets given in the packet
     to base addresses for symfile_map_offsets_to_segments.  */
  else if (data && data->num_segments == 2)
    {
      segments[0] = data->segment_bases[0] + text_addr;
      segments[1] = data->segment_bases[1] + data_addr;
      num_segments = 2;
    }
  /* If the object file has only one segment, assume that it is text
     rather than data; main programs with no writable data are rare,
     but programs with no code are useless.  Of course the code might
     have ended up in the data segment... to detect that we would need
     the permissions here.  */
  else if (data && data->num_segments == 1)
    {
      segments[0] = data->segment_bases[0] + text_addr;
      num_segments = 1;
    }
  /* There's no way to relocate by segment.  */
  else
    do_segments = 0;

  if (do_segments)
    {
      int ret = symfile_map_offsets_to_segments (symfile_objfile->obfd, data,
						 offs, num_segments, segments);

      if (ret == 0 && !do_sections)
	error (_("Can not handle qOffsets TextSeg "
		 "response with this symbol file"));

      if (ret > 0)
	do_sections = 0;
    }

  if (data)
    free_symfile_segment_data (data);

  if (do_sections)
    {
      offs->offsets[SECT_OFF_TEXT (symfile_objfile)] = text_addr;

      /* This is a temporary kludge to force data and bss to use the
	 same offsets because that's what nlmconv does now.  The real
	 solution requires changes to the stub and remote.c that I
	 don't have time to do right now.  */

      offs->offsets[SECT_OFF_DATA (symfile_objfile)] = data_addr;
      offs->offsets[SECT_OFF_BSS (symfile_objfile)] = data_addr;
    }

  objfile_relocate (symfile_objfile, offs);
}

/* Callback for iterate_over_threads.  Set the STOP_REQUESTED flags in
   threads we know are stopped already.  This is used during the
   initial remote connection in non-stop mode --- threads that are
   reported as already being stopped are left stopped.  */

static int
set_stop_requested_callback (struct thread_info *thread, void *data)
{
  /* If we have a stop reply for this thread, it must be stopped.  */
  if (peek_stop_reply (thread->ptid))
    set_stop_requested (thread->ptid, 1);

  return 0;
}

/* Send interrupt_sequence to remote target.  */
static void
send_interrupt_sequence (void)
{
  if (interrupt_sequence_mode == interrupt_sequence_control_c)
    serial_write (remote_desc, "\x03", 1);
  else if (interrupt_sequence_mode == interrupt_sequence_break)
    serial_send_break (remote_desc);
  else if (interrupt_sequence_mode == interrupt_sequence_break_g)
    {
      serial_send_break (remote_desc);
      serial_write (remote_desc, "g", 1);
    }
  else
    internal_error (__FILE__, __LINE__,
		    _("Invalid value for interrupt_sequence_mode: %s."),