// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 */

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <termios.h>
#include "chan_user.h"
#include <os.h>
#include <um_malloc.h>
#include "xterm.h"

struct xterm_chan {
        int pid;
        int helper_pid;
        int chan_fd;
        char *title;
        int device;
        int raw;
        struct termios tt;
};

static void *xterm_init(char *str, int device, const struct chan_opts *opts)
{
        struct xterm_chan *data;

        data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
        if (data == NULL)
                return NULL;
        *data = ((struct xterm_chan) { .pid             = -1,
                                       .helper_pid      = -1,
                                       .chan_fd         = -1,
                                       .device          = device,
                                       .title           = opts->xterm_title,
                                       .raw             = opts->raw } );
        return data;
}

/* Only changed by xterm_setup, which is a setup */
static char *terminal_emulator = CONFIG_XTERM_CHAN_DEFAULT_EMULATOR;
static char *title_switch = "-T";
static char *exec_switch = "-e";

static int __init xterm_setup(char *line, int *add)
{
        *add = 0;
        terminal_emulator = line;

        line = strchr(line, ',');
        if (line == NULL)
                return 0;

        *line++ = '\0';
        if (*line)
                title_switch = line;

        line = strchr(line, ',');
        if (line == NULL)
                return 0;

        *line++ = '\0';
        if (*line)
                exec_switch = line;

        return 0;
}

__uml_setup("xterm=", xterm_setup,
"xterm=<terminal emulator>,<title switch>,<exec switch>\n"
"    Specifies an alternate terminal emulator to use for the debugger,\n"
"    consoles, and serial lines when they are attached to the xterm channel.\n"
"    The values are the terminal emulator binary, the switch it uses to set\n"
"    its title, and the switch it uses to execute a subprocess,\n"
"    respectively.  The title switch must have the form '<switch> title',\n"
"    not '<switch>=title'.  Similarly, the exec switch must have the form\n"
"    '<switch> command arg1 arg2 ...'.\n"
"    The default values are 'xterm=" CONFIG_XTERM_CHAN_DEFAULT_EMULATOR
     ",-T,-e'.\n"
"    Values for gnome-terminal are 'xterm=gnome-terminal,-t,--'.\n\n"
);

static int xterm_open(int input, int output, int primary, void *d,
                      char **dev_out)
{
        struct xterm_chan *data = d;
        int pid, fd, new, err;
        char title[256], file[] = "/tmp/xterm-pipeXXXXXX";
        char *argv[] = { terminal_emulator, title_switch, title, exec_switch,
                         OS_LIB_PATH "/uml/port-helper", "-uml-socket",
                         file, NULL };

        if (access(argv[4], X_OK) < 0)
                argv[4] = "port-helper";

        /* Ensure we are running on Xorg or Wayland. */
        if (!getenv("DISPLAY") && !getenv("WAYLAND_DISPLAY")) {
                printk(UM_KERN_ERR "xterm_open : neither $DISPLAY nor $WAYLAND_DISPLAY is set.\n");
                return -ENODEV;
        }

        /*
         * This business of getting a descriptor to a temp file,
         * deleting the file and closing the descriptor is just to get
         * a known-unused name for the Unix socket that we really
         * want.
         */
        fd = mkstemp(file);
        if (fd < 0) {
                err = -errno;
                printk(UM_KERN_ERR "xterm_open : mkstemp failed, errno = %d\n",
                       errno);
                return err;
        }

        if (unlink(file)) {
                err = -errno;
                printk(UM_KERN_ERR "xterm_open : unlink failed, errno = %d\n",
                       errno);
                close(fd);
                return err;
        }
        close(fd);

        fd = os_create_unix_socket(file, sizeof(file), 1);
        if (fd < 0) {
                printk(UM_KERN_ERR "xterm_open : create_unix_socket failed, "
                       "errno = %d\n", -fd);
                return fd;
        }

        sprintf(title, data->title, data->device);
        pid = run_helper(NULL, NULL, argv);
        if (pid < 0) {
                err = pid;
                printk(UM_KERN_ERR "xterm_open : run_helper failed, "
                       "errno = %d\n", -err);
                goto out_close1;
        }

        err = os_set_fd_block(fd, 0);
        if (err < 0) {
                printk(UM_KERN_ERR "xterm_open : failed to set descriptor "
                       "non-blocking, err = %d\n", -err);
                goto out_kill;
        }

        data->chan_fd = fd;
        new = xterm_fd(fd, &data->helper_pid);
        if (new < 0) {
                err = new;
                printk(UM_KERN_ERR "xterm_open : xterm_fd failed, err = %d\n",
                       -err);
                goto out_kill;
        }

        err = os_set_fd_block(new, 0);
        if (err) {
                printk(UM_KERN_ERR "xterm_open : failed to set xterm "
                       "descriptor non-blocking, err = %d\n", -err);
                goto out_close2;
        }

        CATCH_EINTR(err = tcgetattr(new, &data->tt));
        if (err) {
                new = err;
                goto out_close2;
        }

        if (data->raw) {
                err = raw(new);
                if (err) {
                        new = err;
                        goto out_close2;
                }
        }

        unlink(file);
        data->pid = pid;
        *dev_out = NULL;

        return new;

 out_close2:
        close(new);
 out_kill:
        os_kill_process(pid, 1);
 out_close1:
        close(fd);

        return err;
}

static void xterm_close(int fd, void *d)
{
        struct xterm_chan *data = d;

        if (data->pid != -1)
                os_kill_process(data->pid, 1);
        data->pid = -1;

        if (data->helper_pid != -1)
                os_kill_process(data->helper_pid, 0);
        data->helper_pid = -1;

        if (data->chan_fd != -1)
                os_close_file(data->chan_fd);
        os_close_file(fd);
}

const struct chan_ops xterm_ops = {
        .type           = "xterm",
        .init           = xterm_init,
        .open           = xterm_open,
        .close          = xterm_close,
        .read           = generic_read,
        .write          = generic_write,
        .console_write  = generic_console_write,
        .window_size    = generic_window_size,
        .free           = generic_free,
        .winch          = 1,
};