/*
 *
 * Copyright © 1999 Keith Packard
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of Keith Packard not be used in
 * advertising or publicity pertaining to distribution of the software without
 * specific, written prior permission.  Keith Packard makes no
 * representations about the suitability of this software for any purpose.  It
 * is provided "as is" without express or implied warranty.
 *
 * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#ifdef HAVE_CONFIG_H
#include <kdrive-config.h>
#endif
#include "kdrive.h"
#include <errno.h>
#include <signal.h>
#include <linux/vt.h>
#include <linux/kd.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <X11/keysym.h>
#include <linux/apm_bios.h>

/* These symbols are not defined on musl */
#if !defined(__uid_t) && !defined(__gid_t)
#define __uid_t uid_t
#define __gid_t gid_t
#endif

static int vtno;
int LinuxConsoleFd;
static int LinuxApmFd;
static int activeVT;
static Bool enabled;

static void LinuxVTRequest(int sig)
{
	kdSwitchPending = TRUE;
}

/* Check before chowning -- this avoids touching the file system */
static void LinuxCheckChown(char *file)
{
	struct stat st;
	__uid_t u;
	__gid_t g;

	if (stat(file, &st) < 0)
		return;
	u = getuid();
	g = getgid();
	if (st.st_uid != u || st.st_gid != g)
		chown(file, u, g);
}

static int LinuxInit(void)
{
	int fd = -1;
	LinuxApmFd = -1;
	char vtname[11];
	struct vt_stat vts;

	LinuxConsoleFd = -1;
	/* check if we're run with euid==0 */
	if (geteuid() != 0) {
		FatalError("LinuxInit: Server must be suid root\n");
	}

	if (kdVirtualTerminal >= 0)
		vtno = kdVirtualTerminal;
	else {
		if ((fd = open("/dev/tty0", O_WRONLY, 0)) < 0) {
			FatalError("LinuxInit: Cannot open /dev/tty0 (%s)\n",
				   strerror(errno));
		}
		if ((ioctl(fd, VT_OPENQRY, &vtno) < 0) || (vtno == -1)) {
			FatalError("xf86OpenConsole: Cannot find a free VT\n");
		}
	}
	close(fd);

	sprintf(vtname, "/dev/tty%d", vtno);	/* /dev/tty1-64 */

	if ((LinuxConsoleFd = open(vtname, O_RDWR | O_NDELAY, 0)) < 0) {
		FatalError("LinuxInit: Cannot open %s (%s)\n",
			   vtname, strerror(errno));
	}

	/* change ownership of the vt */
	LinuxCheckChown(vtname);

	/*
	 * the current VT device we're running on is not "console", we want
	 * to grab all consoles too
	 *
	 * Why is this needed?
	 */
	LinuxCheckChown("/dev/tty0");
	/*
	 * Linux doesn't switch to an active vt after the last close of a vt,
	 * so we do this ourselves by remembering which is active now.
	 */
	memset(&vts, '\0', sizeof(vts));	/* valgrind */
	if (ioctl(LinuxConsoleFd, VT_GETSTATE, &vts) == 0) {
		activeVT = vts.v_active;
	}

	return 1;
}

static void LinuxSetSwitchMode(int mode)
{
	struct sigaction act;
	struct vt_mode VT;

	if (ioctl(LinuxConsoleFd, VT_GETMODE, &VT) < 0) {
		FatalError("LinuxInit: VT_GETMODE failed\n");
	}

	if (mode == VT_PROCESS) {
		act.sa_handler = LinuxVTRequest;
		sigemptyset(&act.sa_mask);
		act.sa_flags = 0;
		sigaction(SIGUSR1, &act, 0);

		VT.mode = mode;
		VT.relsig = SIGUSR1;
		VT.acqsig = SIGUSR1;
	} else {
		act.sa_handler = SIG_IGN;
		sigemptyset(&act.sa_mask);
		act.sa_flags = 0;
		sigaction(SIGUSR1, &act, 0);

		VT.mode = mode;
		VT.relsig = 0;
		VT.acqsig = 0;
	}
	if (ioctl(LinuxConsoleFd, VT_SETMODE, &VT) < 0) {
		FatalError("LinuxInit: VT_SETMODE failed\n");
	}
}

static void
LinuxApmBlock(pointer blockData, OSTimePtr pTimeout, pointer pReadmask)
{
}

static Bool LinuxApmRunning;

static void LinuxApmWakeup(pointer blockData, int result, pointer pReadmask)
{
	fd_set *readmask = (fd_set *) pReadmask;

	if (result > 0 && LinuxApmFd >= 0 && FD_ISSET(LinuxApmFd, readmask)) {
		apm_event_t event;
		Bool running = LinuxApmRunning;
		int cmd = APM_IOC_SUSPEND;

		while (read(LinuxApmFd, &event, sizeof(event)) == sizeof(event)) {
			switch (event) {
			case APM_SYS_STANDBY:
			case APM_USER_STANDBY:
				running = FALSE;
				cmd = APM_IOC_STANDBY;
				break;
			case APM_SYS_SUSPEND:
			case APM_USER_SUSPEND:
			case APM_CRITICAL_SUSPEND:
				running = FALSE;
				cmd = APM_IOC_SUSPEND;
				break;
			case APM_NORMAL_RESUME:
			case APM_CRITICAL_RESUME:
			case APM_STANDBY_RESUME:
				running = TRUE;
				break;
			}
		}
		if (running && !LinuxApmRunning) {
			KdResume();
			LinuxApmRunning = TRUE;
		} else if (!running && LinuxApmRunning) {
			KdSuspend();
			LinuxApmRunning = FALSE;
			ioctl(LinuxApmFd, cmd, 0);
		}
	}
}

#ifdef FNONBLOCK
#define NOBLOCK FNONBLOCK
#else
#define NOBLOCK FNDELAY
#endif

static void LinuxEnable(void)
{
	if (enabled)
		return;
	if (kdSwitchPending) {
		kdSwitchPending = FALSE;
		ioctl(LinuxConsoleFd, VT_RELDISP, VT_ACKACQ);
	}
	/*
	 * Open the APM driver
	 */
	LinuxApmFd = open("/dev/apm_bios", 2);
	if (LinuxApmFd < 0 && errno == ENOENT)
		LinuxApmFd = open("/dev/misc/apm_bios", 2);
	if (LinuxApmFd >= 0) {
		LinuxApmRunning = TRUE;
		fcntl(LinuxApmFd, F_SETFL,
		      fcntl(LinuxApmFd, F_GETFL) | NOBLOCK);
		RegisterBlockAndWakeupHandlers(LinuxApmBlock, LinuxApmWakeup,
					       0);
		AddEnabledDevice(LinuxApmFd);
	}

	/*
	 * now get the VT
	 */
	LinuxSetSwitchMode(VT_AUTO);
	if (ioctl(LinuxConsoleFd, VT_ACTIVATE, vtno) != 0) {
		FatalError("LinuxInit: VT_ACTIVATE failed\n");
	}
	if (ioctl(LinuxConsoleFd, VT_WAITACTIVE, vtno) != 0) {
		FatalError("LinuxInit: VT_WAITACTIVE failed\n");
	}
	LinuxSetSwitchMode(VT_PROCESS);
	if (ioctl(LinuxConsoleFd, KDSETMODE, KD_GRAPHICS) < 0) {
		FatalError("LinuxInit: KDSETMODE KD_GRAPHICS failed\n");
	}
	enabled = TRUE;
}

static Bool LinuxSpecialKey(KeySym sym)
{
	struct vt_stat vts;
	int con;

	if (XK_F1 <= sym && sym <= XK_F12) {
		con = sym - XK_F1 + 1;
		memset(&vts, '\0', sizeof(vts));	/* valgrind */
		ioctl(LinuxConsoleFd, VT_GETSTATE, &vts);
		if (con != vts.v_active && (vts.v_state & (1 << con))) {
			ioctl(LinuxConsoleFd, VT_ACTIVATE, con);
			return TRUE;
		}
	}
	return FALSE;
}

static void LinuxDisable(void)
{
	ioctl(LinuxConsoleFd, KDSETMODE, KD_TEXT);	/* Back to text mode ... */
	if (kdSwitchPending) {
		kdSwitchPending = FALSE;
		ioctl(LinuxConsoleFd, VT_RELDISP, 1);
	}
	enabled = FALSE;
	if (LinuxApmFd >= 0) {
		RemoveBlockAndWakeupHandlers(LinuxApmBlock, LinuxApmWakeup, 0);
		RemoveEnabledDevice(LinuxApmFd);
		close(LinuxApmFd);
		LinuxApmFd = -1;
	}
}

static void LinuxFini(void)
{
	struct vt_mode VT;
	struct vt_stat vts;
	int fd;

	if (LinuxConsoleFd < 0)
		return;

	if (ioctl(LinuxConsoleFd, VT_GETMODE, &VT) != -1) {
		VT.mode = VT_AUTO;
		ioctl(LinuxConsoleFd, VT_SETMODE, &VT);	/* set dflt vt handling */
	}
	memset(&vts, '\0', sizeof(vts));	/* valgrind */
	ioctl(LinuxConsoleFd, VT_GETSTATE, &vts);
	if (vtno == vts.v_active) {
		/*
		 * Find a legal VT to switch to, either the one we started from
		 * or the lowest active one that isn't ours
		 */
		if (activeVT < 0 ||
		    activeVT == vts.v_active ||
		    !(vts.v_state & (1 << activeVT))) {
			for (activeVT = 1; activeVT < 16; activeVT++)
				if (activeVT != vtno
				    && (vts.v_state & (1 << activeVT)))
					break;
			if (activeVT == 16)
				activeVT = -1;
		}
		/*
		 * Perform a switch back to the active VT when we were started
		 */
		if (activeVT >= -1) {
			ioctl(LinuxConsoleFd, VT_ACTIVATE, activeVT);
			ioctl(LinuxConsoleFd, VT_WAITACTIVE, activeVT);
			activeVT = -1;
		}
	}
	close(LinuxConsoleFd);	/* make the vt-manager happy */
	fd = open("/dev/tty0", O_RDWR | O_NDELAY, 0);
	if (fd >= 0) {
		memset(&vts, '\0', sizeof(vts));	/* valgrind */
		ioctl(fd, VT_GETSTATE, &vts);
		if (ioctl(fd, VT_DISALLOCATE, vtno) < 0)
			fprintf(stderr,
				"Can't deallocate console %d errno %d\n", vtno,
				errno);
		close(fd);
	}
	return;
}

static const KdOsFuncs LinuxFuncs = {
	LinuxInit,
	LinuxEnable,
	LinuxSpecialKey,
	LinuxDisable,
	LinuxFini,
	0
};

void OsVendorInit(void)
{
	KdOsInit(&LinuxFuncs);
}