/***************************************************************/
/*  mgdb: midipix-specific bits for gdb                        */
/*  Copyright (C) 2019  Z. Gilboa                              */
/*  Released under GPLv2 and GPLv3; see COPYING.MGDB.          */
/***************************************************************/

#include "defs.h"
#include "osabi.h"
#include "config.h"
#include "target.h"
#include "utils.h"
#include "inferior.h"
#include "inf-child.h"
#include "x86-nat.h"

#include <poll.h>
#include <unistd.h>
#include <stdint.h>
#include <stddef.h>
#include <pthread.h>
#include <sys/debug.h>

#define winnt_error(msg) \
	error("%s(): %s.",__FUNCTION__,msg)

#define winnt_perror(msg,pid) \
	error("%s(): %s (pid %d).",__FUNCTION__,msg,pid)

struct winnt_process {
	int	pfd;
	pid_t	pid;
};

static size_t          pcnt;
static winnt_process * plist;

static winnt_process * winnt_plist_expand (void)
{
	struct winnt_process * pnew;
	struct winnt_process * pold;
	size_t                 idx;

	if (!(pnew = (struct winnt_process *)calloc(pcnt+32, sizeof(*pnew))))
		return 0;

	memcpy(
		pnew,plist,
		pcnt*sizeof(*plist));

	pold  = plist;
	plist = pnew;
	pcnt += 32;

	free(pold);

	return pnew;
}

static int winnt_plist_add (pid_t pid, int pfd)
{
	struct winnt_process * pdbg;
	struct winnt_process * pcap;

	for (pdbg=plist, pcap=&plist[pcnt]; pdbg<pcap; pdbg++) {
		if (!pdbg->pid) {
			pdbg->pid = pid;
			pdbg->pfd = pfd;
			return 0;
		}
	}

	return winnt_plist_expand()
		? winnt_plist_add(pid,pfd)
		: -1;
}

static void winnt_plist_remove (pid_t pid)
{
	struct winnt_process * pdbg;
	struct winnt_process * pcap;

	for (pdbg=plist, pcap=&plist[pcnt]; pdbg<pcap; pdbg++) {
		if (pdbg->pid == pid) {
			pdbg->pid = 0;
			return;
		}
	}
}

static int winnt_pfd_from_pid (pid_t pid)
{
	winnt_process * pdbg;
	winnt_process * pcap;

	for (pdbg=plist, pcap=&plist[pcnt]; pdbg<pcap; pdbg++)
		if (pdbg->pid == pid)
			return pdbg->pfd;

	return -1;
}

static nfds_t winnt_poll_one_init (struct pollfd * pfds, pid_t pid)
{
	winnt_process * pdbg;
	winnt_process * pcap;

	for (pdbg=plist, pcap=&plist[pcnt]; pdbg<pcap; pdbg++) {
		if (pdbg->pid == pid) {
			pfds->fd     = pdbg->pfd;
			pfds->events = POLLIN;

			return 1;
		}
	}

	return 0;
}

static nfds_t winnt_poll_init (struct pollfd * pfds)
{
	winnt_process * pdbg;
	winnt_process * pcap;
	struct pollfd * pfd;

	for (pfd=pfds, pdbg=plist, pcap=&plist[pcnt]; pdbg<pcap; pdbg++) {
		if (pdbg->pid) {
			pfd->fd     = pdbg->pfd;
			pfd->events = POLLIN;
			pfd++;
		}
	}

	return pfd - pfds;
}

static void winnt_close (struct target_ops * t)
{
}

static void winnt_xclose (struct target_ops * t)
{
}

static void winnt_attach (struct target_ops * t, const char * args, int from_tty)
{
	pid_t	pid;
	int	pfd;

	if ((pid = parse_pid_to_attach(args)) < 0) {
		winnt_error ("cannot parse pid to attach");
	}


	if ((pfd = __dbg_attach(pid)) < 0) {
		winnt_perror ("cannot attach to process",pid);
	}


	if (__dbg_rbreak(pfd) < 0) {
		__dbg_detach(pfd);
		close(pfd);
		winnt_perror ("could not issue a breakpoint in process",pid);
	}


	if (winnt_plist_add(pid,pfd) < 0) {
		__dbg_detach(pfd);
		close(pfd);
		winnt_error ("could not expand debuggee list");
	}
}

static void winnt_detach (struct target_ops * t, const char * args, int from_tty)
{
	pid_t	pid;
	int	pfd;

	if ((pid = ptid_get_pid(inferior_ptid)) < 0)
		winnt_error ("cannot parse pid to detach");

	if ((pfd = winnt_pfd_from_pid(pid)) < 0)
		winnt_perror ("debuggee record does not exist",pid);

	if (__dbg_detach(pfd) < 0)
		winnt_perror ("could not attach from process",pid);

	if (close(pfd) < 0)
		winnt_perror ("failed to close process file descriptor",pid);

	winnt_plist_remove(pid);

	x86_cleanup_dregs();
}

static ptid_t winnt_wait(
	struct target_ops * t,
	ptid_t ptid,
	struct target_waitstatus * waitstatus,
	int target_options)
{
	struct __dbg_event      dbgevent;
	struct pollfd           pollfdbuf[512];
	struct pollfd *         pfds;
	struct pollfd *         pfd;
	nfds_t                  nfds,i;

	if (pcnt*sizeof(*pfds) < sizeof(pollfdbuf))
		pfds = pollfdbuf;
	else if (!(pfds = (struct pollfd *)calloc(pcnt,sizeof(*pfds))))
		return null_ptid;

	nfds = (ptid.pid > 0)
		? winnt_poll_one_init(pfds,ptid.pid)
		: winnt_poll_init(pfds);

	if (poll(pfds,nfds,-1) < 0)
		return null_ptid;

	for (i=0, pfd=0; i<nfds && !pfd; i++)
		if (pfds[i].revents & POLLIN)
			pfd = &pfds[i];

	if (!pfd)
		return null_ptid;

	if (__dbg_event_query_one(pfd->fd,&dbgevent) < 0)
		return null_ptid;

	return ptid_build(
		dbgevent.cpid ? dbgevent.cpid : dbgevent.syspid,
		0,
		dbgevent.ctid ? dbgevent.ctid : dbgevent.systid);
}

static void winnt_resume (
	struct target_ops * t,
	ptid_t ptid, int step,
	enum gdb_signal sig)
{
}

static void winnt_kill (struct target_ops * t)
{
	/* current_inferior() */
}

static void winnt_mourn_inferior (struct target_ops * t)
{
	/* update plist, etc. */
}

static void winnt_create_inferior(
	struct  target_ops * ops,
	char *  exec_file,
	char *  allargs,
	char ** in_env,
	int     from_tty)
{
	winnt_error("Not implemented");
}

static target_ops * winnt_target_alloc (void)
{
	target_ops * t = inf_child_target();

	t->to_attach_no_wait            = 1;
	t->to_has_thread_control        = 1;

	t->to_close                     = winnt_close;
	t->to_xclose                    = winnt_xclose;

	t->to_attach                    = winnt_attach;
	t->to_detach                    = winnt_detach;

	t->to_wait                      = winnt_wait;
	t->to_resume                    = winnt_resume;

	t->to_kill                      = winnt_kill;
	t->to_mourn_inferior            = winnt_mourn_inferior;
	t->to_create_inferior           = winnt_create_inferior;

	x86_use_watchpoints(t);

	return t;
}



extern initialize_file_ftype _initialize_winnt_nat;

void
_initialize_winnt_nat(void)
{
	add_target(winnt_target_alloc());
}