hw/char/xen_console.c - qemu - Git at Google

 /*
  *  Copyright (C) International Business Machines  Corp., 2005
  *  Author(s): Anthony Liguori <aliguori@us.ibm.com>
  *
  *  Copyright (C) Red Hat 2007
  *
  *  Xen Console
  *
  *  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; under version 2 of the License.
  *
  *  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/>.
  */

 #include "qemu/osdep.h"
 #include <sys/select.h>
 #include <termios.h>

 #include "qapi/error.h"
 #include "sysemu/sysemu.h"
 #include "chardev/char-fe.h"
 #include "hw/xen/xen-legacy-backend.h"

 #include "hw/xen/interface/io/console.h"

 struct buffer {
     uint8_t *data;
     size_t consumed;
     size_t size;
     size_t capacity;
     size_t max_capacity;
 };

 struct XenConsole {
     struct XenLegacyDevice  xendev;  /* must be first */
     struct buffer     buffer;
     char              console[XEN_BUFSIZE];
     int               ring_ref;
     void              *sring;
     CharBackend       chr;
     int               backlog;
 };

 static void buffer_append(struct XenConsole *con)
 {
     struct buffer *buffer = &con->buffer;
     XENCONS_RING_IDX cons, prod, size;
     struct xencons_interface *intf = con->sring;

     cons = intf->out_cons;
     prod = intf->out_prod;
     xen_mb();

     size = prod - cons;
     if ((size == 0) || (size > sizeof(intf->out)))
         return;

     if ((buffer->capacity - buffer->size) < size) {
         buffer->capacity += (size + 1024);
         buffer->data = g_realloc(buffer->data, buffer->capacity);
     }

     while (cons != prod)
         buffer->data[buffer->size++] = intf->out[
             MASK_XENCONS_IDX(cons++, intf->out)];

     xen_mb();
     intf->out_cons = cons;
     xen_pv_send_notify(&con->xendev);

     if (buffer->max_capacity &&
         buffer->size > buffer->max_capacity) {
         /* Discard the middle of the data. */

         size_t over = buffer->size - buffer->max_capacity;
         uint8_t *maxpos = buffer->data + buffer->max_capacity;

         memmove(maxpos - over, maxpos, over);
         buffer->data = g_realloc(buffer->data, buffer->max_capacity);
         buffer->size = buffer->capacity = buffer->max_capacity;

         if (buffer->consumed > buffer->max_capacity - over)
             buffer->consumed = buffer->max_capacity - over;
     }
 }

 static void buffer_advance(struct buffer *buffer, size_t len)
 {
     buffer->consumed += len;
     if (buffer->consumed == buffer->size) {
         buffer->consumed = 0;
         buffer->size = 0;
     }
 }

 static int ring_free_bytes(struct XenConsole *con)
 {
     struct xencons_interface *intf = con->sring;
     XENCONS_RING_IDX cons, prod, space;

     cons = intf->in_cons;
     prod = intf->in_prod;
     xen_mb();

     space = prod - cons;
     if (space > sizeof(intf->in))
         return 0; /* ring is screwed: ignore it */

     return (sizeof(intf->in) - space);
 }

 static int xencons_can_receive(void *opaque)
 {
     struct XenConsole *con = opaque;
     return ring_free_bytes(con);
 }

 static void xencons_receive(void *opaque, const uint8_t *buf, int len)
 {
     struct XenConsole *con = opaque;
     struct xencons_interface *intf = con->sring;
     XENCONS_RING_IDX prod;
     int i, max;

     max = ring_free_bytes(con);
     /* The can_receive() func limits this, but check again anyway */
     if (max < len)
         len = max;

     prod = intf->in_prod;
     for (i = 0; i < len; i++) {
         intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
             buf[i];
     }
     xen_wmb();
     intf->in_prod = prod;
     xen_pv_send_notify(&con->xendev);
 }

 static void xencons_send(struct XenConsole *con)
 {
     ssize_t len, size;

     size = con->buffer.size - con->buffer.consumed;
     if (qemu_chr_fe_backend_connected(&con->chr)) {
         len = qemu_chr_fe_write(&con->chr,
                                 con->buffer.data + con->buffer.consumed,
                                 size);
     } else {
         len = size;
     }
     if (len < 1) {
         if (!con->backlog) {
             con->backlog = 1;
             xen_pv_printf(&con->xendev, 1,
                           "backlog piling up, nobody listening?\n");
         }
     } else {
         buffer_advance(&con->buffer, len);
         if (con->backlog && len == size) {
             con->backlog = 0;
             xen_pv_printf(&con->xendev, 1, "backlog is gone\n");
         }
     }
 }

 /* -------------------------------------------------------------------- */

 static int store_con_info(struct XenConsole *con)
 {
     Chardev *cs = qemu_chr_fe_get_driver(&con->chr);
     char *pts = NULL;
     char *dom_path;
     g_autoptr(GString) path = NULL;

     /* Only continue if we're talking to a pty. */
     if (!CHARDEV_IS_PTY(cs)) {
         return 0;
     }
     pts = cs->filename + 4;

     dom_path = qemu_xen_xs_get_domain_path(xenstore, xen_domid);
     if (!dom_path) {
         return 0;
     }

     path = g_string_new(dom_path);
     free(dom_path);

     if (con->xendev.dev) {
         g_string_append_printf(path, "/device/console/%d", con->xendev.dev);
     } else {
         g_string_append(path, "/console");
     }
     g_string_append(path, "/tty");

     if (xenstore_write_str(con->console, path->str, pts)) {
         fprintf(stderr, "xenstore_write_str for '%s' fail", path->str);
         return -1;
     }
     return 0;
 }

 static int con_init(struct XenLegacyDevice *xendev)
 {
     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
     char *type, *dom, label[32];
     int ret = 0;
     const char *output;

     /* setup */
     dom = qemu_xen_xs_get_domain_path(xenstore, con->xendev.dom);
     if (!xendev->dev) {
         snprintf(con->console, sizeof(con->console), "%s/console", dom);
     } else {
         snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev);
     }
     free(dom);

     type = xenstore_read_str(con->console, "type");
     if (!type || strcmp(type, "ioemu") != 0) {
         xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type);
         ret = -1;
         goto out;
     }

     output = xenstore_read_str(con->console, "output");

     /* no Xen override, use qemu output device */
     if (output == NULL) {
         if (con->xendev.dev) {
             qemu_chr_fe_init(&con->chr, serial_hd(con->xendev.dev),
                              &error_abort);
         }
     } else {
         snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
         qemu_chr_fe_init(&con->chr,
                          /*
                           * FIXME: sure we want to support implicit
                           * muxed monitors here?
                           */
                          qemu_chr_new_mux_mon(label, output, NULL),
                          &error_abort);
     }

     store_con_info(con);

 out:
     g_free(type);
     return ret;
 }

 static int con_initialise(struct XenLegacyDevice *xendev)
 {
     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
     int limit;

     if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
         return -1;
     if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
         return -1;
     if (xenstore_read_int(con->console, "limit", &limit) == 0)
         con->buffer.max_capacity = limit;

     if (!xendev->dev) {
         xen_pfn_t mfn = con->ring_ref;
         con->sring = qemu_xen_foreignmem_map(con->xendev.dom, NULL,
                                              PROT_READ | PROT_WRITE,
                                              1, &mfn, NULL);
     } else {
         con->sring = xen_be_map_grant_ref(xendev, con->ring_ref,
                                           PROT_READ | PROT_WRITE);
     }
     if (!con->sring)
         return -1;

     xen_be_bind_evtchn(&con->xendev);
     qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
                              xencons_receive, NULL, NULL, con, NULL, true);

     xen_pv_printf(xendev, 1,
                   "ring mfn %d, remote port %d, local port %d, limit %zd\n",
                   con->ring_ref,
                   con->xendev.remote_port,
                   con->xendev.local_port,
                   con->buffer.max_capacity);
     return 0;
 }

 static void con_disconnect(struct XenLegacyDevice *xendev)
 {
     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);

     qemu_chr_fe_deinit(&con->chr, false);
     xen_pv_unbind_evtchn(&con->xendev);

     if (con->sring) {
         if (!xendev->dev) {
             qemu_xen_foreignmem_unmap(con->sring, 1);
         } else {
             xen_be_unmap_grant_ref(xendev, con->sring, con->ring_ref);
         }
         con->sring = NULL;
     }
 }

 static void con_event(struct XenLegacyDevice *xendev)
 {
     struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);

     buffer_append(con);
     if (con->buffer.size - con->buffer.consumed)
         xencons_send(con);
 }

 /* -------------------------------------------------------------------- */

 struct XenDevOps xen_console_ops = {
     .size       = sizeof(struct XenConsole),
     .flags      = DEVOPS_FLAG_IGNORE_STATE|DEVOPS_FLAG_NEED_GNTDEV,
     .init       = con_init,
     .initialise = con_initialise,
     .event      = con_event,
     .disconnect = con_disconnect,
 };
	/*
	* Copyright (C) International Business Machines Corp., 2005
	* Author(s): Anthony Liguori <aliguori@us.ibm.com>
	*
	* Copyright (C) Red Hat 2007
	*
	* Xen Console
	*
	* 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; under version 2 of the License.
	*
	* 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/>.
	*/

	#include "qemu/osdep.h"
	#include <sys/select.h>
	#include <termios.h>

	#include "qapi/error.h"
	#include "sysemu/sysemu.h"
	#include "chardev/char-fe.h"
	#include "hw/xen/xen-legacy-backend.h"

	#include "hw/xen/interface/io/console.h"

	struct buffer {
	uint8_t *data;
	size_t consumed;
	size_t size;
	size_t capacity;
	size_t max_capacity;
	};

	struct XenConsole {
	struct XenLegacyDevice xendev; /* must be first */
	struct buffer buffer;
	char console[XEN_BUFSIZE];
	int ring_ref;
	void *sring;
	CharBackend chr;
	int backlog;
	};

	static void buffer_append(struct XenConsole *con)
	{
	struct buffer *buffer = &con->buffer;
	XENCONS_RING_IDX cons, prod, size;
	struct xencons_interface *intf = con->sring;

	cons = intf->out_cons;
	prod = intf->out_prod;
	xen_mb();

	size = prod - cons;
	if ((size == 0) \|\| (size > sizeof(intf->out)))
	return;

	if ((buffer->capacity - buffer->size) < size) {
	buffer->capacity += (size + 1024);
	buffer->data = g_realloc(buffer->data, buffer->capacity);
	}

	while (cons != prod)
	buffer->data[buffer->size++] = intf->out[
	MASK_XENCONS_IDX(cons++, intf->out)];

	xen_mb();
	intf->out_cons = cons;
	xen_pv_send_notify(&con->xendev);

	if (buffer->max_capacity &&
	buffer->size > buffer->max_capacity) {
	/* Discard the middle of the data. */

	size_t over = buffer->size - buffer->max_capacity;
	uint8_t *maxpos = buffer->data + buffer->max_capacity;

	memmove(maxpos - over, maxpos, over);
	buffer->data = g_realloc(buffer->data, buffer->max_capacity);
	buffer->size = buffer->capacity = buffer->max_capacity;

	if (buffer->consumed > buffer->max_capacity - over)
	buffer->consumed = buffer->max_capacity - over;
	}
	}

	static void buffer_advance(struct buffer *buffer, size_t len)
	{
	buffer->consumed += len;
	if (buffer->consumed == buffer->size) {
	buffer->consumed = 0;
	buffer->size = 0;
	}
	}

	static int ring_free_bytes(struct XenConsole *con)
	{
	struct xencons_interface *intf = con->sring;
	XENCONS_RING_IDX cons, prod, space;

	cons = intf->in_cons;
	prod = intf->in_prod;
	xen_mb();

	space = prod - cons;
	if (space > sizeof(intf->in))
	return 0; /* ring is screwed: ignore it */

	return (sizeof(intf->in) - space);
	}

	static int xencons_can_receive(void *opaque)
	{
	struct XenConsole *con = opaque;
	return ring_free_bytes(con);
	}

	static void xencons_receive(void opaque, const uint8_t buf, int len)
	{
	struct XenConsole *con = opaque;
	struct xencons_interface *intf = con->sring;
	XENCONS_RING_IDX prod;
	int i, max;

	max = ring_free_bytes(con);
	/* The can_receive() func limits this, but check again anyway */
	if (max < len)
	len = max;

	prod = intf->in_prod;
	for (i = 0; i < len; i++) {
	intf->in[MASK_XENCONS_IDX(prod++, intf->in)] =
	buf[i];
	}
	xen_wmb();
	intf->in_prod = prod;
	xen_pv_send_notify(&con->xendev);
	}

	static void xencons_send(struct XenConsole *con)
	{
	ssize_t len, size;

	size = con->buffer.size - con->buffer.consumed;
	if (qemu_chr_fe_backend_connected(&con->chr)) {
	len = qemu_chr_fe_write(&con->chr,
	con->buffer.data + con->buffer.consumed,
	size);
	} else {
	len = size;
	}
	if (len < 1) {
	if (!con->backlog) {
	con->backlog = 1;
	xen_pv_printf(&con->xendev, 1,
	"backlog piling up, nobody listening?\n");
	}
	} else {
	buffer_advance(&con->buffer, len);
	if (con->backlog && len == size) {
	con->backlog = 0;
	xen_pv_printf(&con->xendev, 1, "backlog is gone\n");
	}
	}
	}

	/* -------------------------------------------------------------------- */

	static int store_con_info(struct XenConsole *con)
	{
	Chardev *cs = qemu_chr_fe_get_driver(&con->chr);
	char *pts = NULL;
	char *dom_path;
	g_autoptr(GString) path = NULL;

	/* Only continue if we're talking to a pty. */
	if (!CHARDEV_IS_PTY(cs)) {
	return 0;
	}
	pts = cs->filename + 4;

	dom_path = qemu_xen_xs_get_domain_path(xenstore, xen_domid);
	if (!dom_path) {
	return 0;
	}

	path = g_string_new(dom_path);
	free(dom_path);

	if (con->xendev.dev) {
	g_string_append_printf(path, "/device/console/%d", con->xendev.dev);
	} else {
	g_string_append(path, "/console");
	}
	g_string_append(path, "/tty");

	if (xenstore_write_str(con->console, path->str, pts)) {
	fprintf(stderr, "xenstore_write_str for '%s' fail", path->str);
	return -1;
	}
	return 0;
	}

	static int con_init(struct XenLegacyDevice *xendev)
	{
	struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
	char type, dom, label[32];
	int ret = 0;
	const char *output;

	/* setup */
	dom = qemu_xen_xs_get_domain_path(xenstore, con->xendev.dom);
	if (!xendev->dev) {
	snprintf(con->console, sizeof(con->console), "%s/console", dom);
	} else {
	snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev);
	}
	free(dom);

	type = xenstore_read_str(con->console, "type");
	if (!type \|\| strcmp(type, "ioemu") != 0) {
	xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type);
	ret = -1;
	goto out;
	}

	output = xenstore_read_str(con->console, "output");

	/* no Xen override, use qemu output device */
	if (output == NULL) {
	if (con->xendev.dev) {
	qemu_chr_fe_init(&con->chr, serial_hd(con->xendev.dev),
	&error_abort);
	}
	} else {
	snprintf(label, sizeof(label), "xencons%d", con->xendev.dev);
	qemu_chr_fe_init(&con->chr,
	/*
	* FIXME: sure we want to support implicit
	* muxed monitors here?
	*/
	qemu_chr_new_mux_mon(label, output, NULL),
	&error_abort);
	}

	store_con_info(con);

	out:
	g_free(type);
	return ret;
	}

	static int con_initialise(struct XenLegacyDevice *xendev)
	{
	struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);
	int limit;

	if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1)
	return -1;
	if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1)
	return -1;
	if (xenstore_read_int(con->console, "limit", &limit) == 0)
	con->buffer.max_capacity = limit;

	if (!xendev->dev) {
	xen_pfn_t mfn = con->ring_ref;
	con->sring = qemu_xen_foreignmem_map(con->xendev.dom, NULL,
	PROT_READ \| PROT_WRITE,
	1, &mfn, NULL);
	} else {
	con->sring = xen_be_map_grant_ref(xendev, con->ring_ref,
	PROT_READ \| PROT_WRITE);
	}
	if (!con->sring)
	return -1;

	xen_be_bind_evtchn(&con->xendev);
	qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive,
	xencons_receive, NULL, NULL, con, NULL, true);

	xen_pv_printf(xendev, 1,
	"ring mfn %d, remote port %d, local port %d, limit %zd\n",
	con->ring_ref,
	con->xendev.remote_port,
	con->xendev.local_port,
	con->buffer.max_capacity);
	return 0;
	}

	static void con_disconnect(struct XenLegacyDevice *xendev)
	{
	struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);

	qemu_chr_fe_deinit(&con->chr, false);
	xen_pv_unbind_evtchn(&con->xendev);

	if (con->sring) {
	if (!xendev->dev) {
	qemu_xen_foreignmem_unmap(con->sring, 1);
	} else {
	xen_be_unmap_grant_ref(xendev, con->sring, con->ring_ref);
	}
	con->sring = NULL;
	}
	}

	static void con_event(struct XenLegacyDevice *xendev)
	{
	struct XenConsole *con = container_of(xendev, struct XenConsole, xendev);

	buffer_append(con);
	if (con->buffer.size - con->buffer.consumed)
	xencons_send(con);
	}

	/* -------------------------------------------------------------------- */

	struct XenDevOps xen_console_ops = {
	.size = sizeof(struct XenConsole),
	.flags = DEVOPS_FLAG_IGNORE_STATE\|DEVOPS_FLAG_NEED_GNTDEV,
	.init = con_init,
	.initialise = con_initialise,
	.event = con_event,
	.disconnect = con_disconnect,
	};