xterm.c

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/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#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;
    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,
                       .device      = device,
                       .title       = opts->xterm_title,
                       .raw         = opts->raw } );
    return data;
}

/* Only changed by xterm_setup, which is a setup */
static char *terminal_emulator = "xterm";
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=xterm,-T,-e'.  Values for gnome-terminal\n"
"    are 'xterm=gnome-terminal,-t,-x'.\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";

    /*
     * Check that DISPLAY is set, this doesn't guarantee the xterm
     * will work but w/o it we can be pretty sure it won't.
     */
    if (getenv("DISPLAY") == NULL) {
        printk(UM_KERN_ERR "xterm_open: $DISPLAY not 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;
    }

    new = xterm_fd(fd, &data->helper_pid);
    if (new < 0) {
        err = new;
        printk(UM_KERN_ERR "xterm_open : os_rcv_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;

    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,
};