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qemu-ga: move channel/transport functionality into wrapper class

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This is mostly in preparation for the win32 port, which won't use
GIO channels for reasons that will be made clearer later. Here the
GAChannel class is just a loose wrapper around GIOChannel
calls/callbacks, but we also roll in the logic/configuration for
various channel types and managing unix socket connections, which makes
the abstraction much more complete and further aids in the win32 port
since isa-serial/unix-listen will not be supported initially.

There's also a bit of refactoring in the main logic to consolidate the
exit paths so we can do common cleanup for things like pid files, which
weren't always cleaned up previously.
This commit is contained in:
Michael Roth 2012-01-19 00:18:20 -06:00
parent 54383726dd
commit 125b310e1d
5 changed files with 355 additions and 233 deletions
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1
Makefile.objs
View File

@ -425,6 +425,7 @@ common-obj-y += qmp.o hmp.o
# guest agent
qga-nested-y = guest-agent-commands.o guest-agent-command-state.o
qga-nested-y += channel-posix.o
qga-obj-y = $(addprefix qga/, $(qga-nested-y))
qga-obj-y += qemu-ga.o qemu-sockets.o module.o qemu-option.o
qga-obj-$(CONFIG_WIN32) += oslib-win32.o

306
qemu-ga.c
View File

@ -15,9 +15,7 @@
#include <stdbool.h>
#include <glib.h>
#include <getopt.h>
#include <termios.h>
#include <syslog.h>
#include "qemu_socket.h"
#include "json-streamer.h"
#include "json-parser.h"
#include "qint.h"
@ -28,19 +26,15 @@
#include "qerror.h"
#include "error_int.h"
#include "qapi/qmp-core.h"
#include "qga/channel.h"
#define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent.0"
#define QGA_PIDFILE_DEFAULT "/var/run/qemu-ga.pid"
#define QGA_BAUDRATE_DEFAULT B38400 /* for isa-serial channels */
#define QGA_TIMEOUT_DEFAULT 30*1000 /* ms */
struct GAState {
JSONMessageParser parser;
GMainLoop *main_loop;
GIOChannel *conn_channel;
GIOChannel *listen_channel;
const char *path;
const char *method;
GAChannel *channel;
bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
GACommandState *command_state;
GLogLevelFlags log_level;
@ -59,7 +53,7 @@ static void quit_handler(int sig)
}
}
static void register_signal_handlers(void)
static gboolean register_signal_handlers(void)
{
struct sigaction sigact;
int ret;
@ -70,12 +64,14 @@ static void register_signal_handlers(void)
ret = sigaction(SIGINT, &sigact, NULL);
if (ret == -1) {
g_error("error configuring signal handler: %s", strerror(errno));
exit(EXIT_FAILURE);
return false;
}
ret = sigaction(SIGTERM, &sigact, NULL);
if (ret == -1) {
g_error("error configuring signal handler: %s", strerror(errno));
return false;
}
return true;
}
static void usage(const char *cmd)
@ -100,8 +96,6 @@ static void usage(const char *cmd)
, cmd, QGA_VERSION, QGA_VIRTIO_PATH_DEFAULT, QGA_PIDFILE_DEFAULT);
}
static void conn_channel_close(GAState *s);
static const char *ga_log_level_str(GLogLevelFlags level)
{
switch (level & G_LOG_LEVEL_MASK) {
@ -210,40 +204,13 @@ fail:
exit(EXIT_FAILURE);
}
static int conn_channel_send_buf(GIOChannel *channel, const char *buf,
gsize count)
static int send_response(GAState *s, QObject *payload)
{
GError *err = NULL;
gsize written = 0;
GIOStatus status;
while (count) {
status = g_io_channel_write_chars(channel, buf, count, &written, &err);
g_debug("sending data, count: %d", (int)count);
if (err != NULL) {
g_warning("error sending newline: %s", err->message);
return err->code;
}
if (status == G_IO_STATUS_ERROR || status == G_IO_STATUS_EOF) {
return -EPIPE;
}
if (status == G_IO_STATUS_NORMAL) {
count -= written;
}
}
return 0;
}
static int conn_channel_send_payload(GIOChannel *channel, QObject *payload)
{
int ret = 0;
const char *buf;
QString *payload_qstr;
GError *err = NULL;
GIOStatus status;
g_assert(payload && channel);
g_assert(payload && s->channel);
payload_qstr = qobject_to_json(payload);
if (!payload_qstr) {
@ -252,24 +219,13 @@ static int conn_channel_send_payload(GIOChannel *channel, QObject *payload)
qstring_append_chr(payload_qstr, '\n');
buf = qstring_get_str(payload_qstr);
ret = conn_channel_send_buf(channel, buf, strlen(buf));
if (ret) {
goto out_free;
}
g_io_channel_flush(channel, &err);
if (err != NULL) {
g_warning("error flushing payload: %s", err->message);
ret = err->code;
goto out_free;
}
out_free:
status = ga_channel_write_all(s->channel, buf, strlen(buf));
QDECREF(payload_qstr);
if (err) {
g_error_free(err);
if (status != G_IO_STATUS_NORMAL) {
return -EIO;
}
return ret;
return 0;
}
static void process_command(GAState *s, QDict *req)
@ -281,9 +237,9 @@ static void process_command(GAState *s, QDict *req)
g_debug("processing command");
rsp = qmp_dispatch(QOBJECT(req));
if (rsp) {
ret = conn_channel_send_payload(s->conn_channel, rsp);
ret = send_response(s, rsp);
if (ret) {
g_warning("error sending payload: %s", strerror(ret));
g_warning("error sending response: %s", strerror(ret));
}
qobject_decref(rsp);
} else {
@ -333,38 +289,42 @@ static void process_event(JSONMessageParser *parser, QList *tokens)
qdict_put_obj(qdict, "error", error_get_qobject(err));
error_free(err);
}
ret = conn_channel_send_payload(s->conn_channel, QOBJECT(qdict));
ret = send_response(s, QOBJECT(qdict));
if (ret) {
g_warning("error sending payload: %s", strerror(ret));
g_warning("error sending error response: %s", strerror(ret));
}
}
QDECREF(qdict);
}
static gboolean conn_channel_read(GIOChannel *channel, GIOCondition condition,
gpointer data)
/* false return signals GAChannel to close the current client connection */
static gboolean channel_event_cb(GIOCondition condition, gpointer data)
{
GAState *s = data;
gchar buf[1024];
gchar buf[QGA_READ_COUNT_DEFAULT+1];
gsize count;
GError *err = NULL;
memset(buf, 0, 1024);
GIOStatus status = g_io_channel_read_chars(channel, buf, 1024,
&count, &err);
GIOStatus status = ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count);
if (err != NULL) {
g_warning("error reading channel: %s", err->message);
conn_channel_close(s);
g_error_free(err);
return false;
}
switch (status) {
case G_IO_STATUS_ERROR:
g_warning("problem");
g_warning("error reading channel");
return false;
case G_IO_STATUS_NORMAL:
buf[count] = 0;
g_debug("read data, count: %d, data: %s", (int)count, buf);
json_message_parser_feed(&s->parser, (char *)buf, (int)count);
break;
case G_IO_STATUS_EOF:
g_debug("received EOF");
if (!s->virtio) {
return false;
}
case G_IO_STATUS_AGAIN:
/* virtio causes us to spin here when no process is attached to
* host-side chardev. sleep a bit to mitigate this
@ -373,180 +333,49 @@ static gboolean conn_channel_read(GIOChannel *channel, GIOCondition condition,
usleep(100*1000);
}
return true;
case G_IO_STATUS_EOF:
g_debug("received EOF");
conn_channel_close(s);
if (s->virtio) {
return true;
}
return false;
default:
g_warning("unknown channel read status, closing");
conn_channel_close(s);
return false;
}
return true;
}
static int conn_channel_add(GAState *s, int fd)
static gboolean channel_init(GAState *s, const gchar *method, const gchar *path)
{
GIOChannel *conn_channel;
GError *err = NULL;
GAChannelMethod channel_method;
g_assert(s && !s->conn_channel);
conn_channel = g_io_channel_unix_new(fd);
g_assert(conn_channel);
g_io_channel_set_encoding(conn_channel, NULL, &err);
if (err != NULL) {
g_warning("error setting channel encoding to binary");
g_error_free(err);
return -1;
}
g_io_add_watch(conn_channel, G_IO_IN | G_IO_HUP,
conn_channel_read, s);
s->conn_channel = conn_channel;
return 0;
}
static gboolean listen_channel_accept(GIOChannel *channel,
GIOCondition condition, gpointer data)
{
GAState *s = data;
g_assert(channel != NULL);
int ret, conn_fd;
bool accepted = false;
struct sockaddr_un addr;
socklen_t addrlen = sizeof(addr);
conn_fd = qemu_accept(g_io_channel_unix_get_fd(s->listen_channel),
(struct sockaddr *)&addr, &addrlen);
if (conn_fd == -1) {
g_warning("error converting fd to gsocket: %s", strerror(errno));
goto out;
}
fcntl(conn_fd, F_SETFL, O_NONBLOCK);
ret = conn_channel_add(s, conn_fd);
if (ret) {
g_warning("error setting up connection");
goto out;
}
accepted = true;
out:
/* only accept 1 connection at a time */
return !accepted;
}
/* start polling for readable events on listen fd, new==true
* indicates we should use the existing s->listen_channel
*/
static int listen_channel_add(GAState *s, int listen_fd, bool new)
{
if (new) {
s->listen_channel = g_io_channel_unix_new(listen_fd);
}
g_io_add_watch(s->listen_channel, G_IO_IN,
listen_channel_accept, s);
return 0;
}
/* cleanup state for closed connection/session, start accepting new
* connections if we're in listening mode
*/
static void conn_channel_close(GAState *s)
{
if (strcmp(s->method, "unix-listen") == 0) {
g_io_channel_shutdown(s->conn_channel, true, NULL);
listen_channel_add(s, 0, false);
} else if (strcmp(s->method, "virtio-serial") == 0) {
/* we spin on EOF for virtio-serial, so back off a bit. also,
* dont close the connection in this case, it'll resume normal
* operation when another process connects to host chardev
*/
usleep(100*1000);
goto out_noclose;
}
g_io_channel_unref(s->conn_channel);
s->conn_channel = NULL;
out_noclose:
return;
}
static void init_guest_agent(GAState *s)
{
struct termios tio;
int ret, fd;
if (s->method == NULL) {
/* try virtio-serial as our default */
s->method = "virtio-serial";
if (method == NULL) {
method = "virtio-serial";
}
if (s->path == NULL) {
if (strcmp(s->method, "virtio-serial") != 0) {
if (path == NULL) {
if (strcmp(method, "virtio-serial") != 0) {
g_critical("must specify a path for this channel");
exit(EXIT_FAILURE);
return false;
}
/* try the default path for the virtio-serial port */
s->path = QGA_VIRTIO_PATH_DEFAULT;
path = QGA_VIRTIO_PATH_DEFAULT;
}
if (strcmp(s->method, "virtio-serial") == 0) {
s->virtio = true;
fd = qemu_open(s->path, O_RDWR | O_NONBLOCK | O_ASYNC);
if (fd == -1) {
g_critical("error opening channel: %s", strerror(errno));
exit(EXIT_FAILURE);
}
ret = conn_channel_add(s, fd);
if (ret) {
g_critical("error adding channel to main loop");
exit(EXIT_FAILURE);
}
} else if (strcmp(s->method, "isa-serial") == 0) {
fd = qemu_open(s->path, O_RDWR | O_NOCTTY);
if (fd == -1) {
g_critical("error opening channel: %s", strerror(errno));
exit(EXIT_FAILURE);
}
tcgetattr(fd, &tio);
/* set up serial port for non-canonical, dumb byte streaming */
tio.c_iflag &= ~(IGNBRK | BRKINT | IGNPAR | PARMRK | INPCK | ISTRIP |
INLCR | IGNCR | ICRNL | IXON | IXOFF | IXANY |
IMAXBEL);
tio.c_oflag = 0;
tio.c_lflag = 0;
tio.c_cflag |= QGA_BAUDRATE_DEFAULT;
/* 1 available byte min or reads will block (we'll set non-blocking
* elsewhere, else we have to deal with read()=0 instead)
*/
tio.c_cc[VMIN] = 1;
tio.c_cc[VTIME] = 0;
/* flush everything waiting for read/xmit, it's garbage at this point */
tcflush(fd, TCIFLUSH);
tcsetattr(fd, TCSANOW, &tio);
ret = conn_channel_add(s, fd);
if (ret) {
g_error("error adding channel to main loop");
}
} else if (strcmp(s->method, "unix-listen") == 0) {
fd = unix_listen(s->path, NULL, strlen(s->path));
if (fd == -1) {
g_critical("error opening path: %s", strerror(errno));
exit(EXIT_FAILURE);
}
ret = listen_channel_add(s, fd, true);
if (ret) {
g_critical("error binding/listening to specified socket");
exit(EXIT_FAILURE);
}
if (strcmp(method, "virtio-serial") == 0) {
s->virtio = true; /* virtio requires special handling in some cases */
channel_method = GA_CHANNEL_VIRTIO_SERIAL;
} else if (strcmp(method, "isa-serial") == 0) {
channel_method = GA_CHANNEL_ISA_SERIAL;
} else if (strcmp(method, "unix-listen") == 0) {
channel_method = GA_CHANNEL_UNIX_LISTEN;
} else {
g_critical("unsupported channel method/type: %s", s->method);
exit(EXIT_FAILURE);
g_critical("unsupported channel method/type: %s", method);
return false;
}
json_message_parser_init(&s->parser, process_event);
s->main_loop = g_main_loop_new(NULL, false);
s->channel = ga_channel_new(channel_method, path, channel_event_cb, s);
if (!s->channel) {
g_critical("failed to create guest agent channel");
return false;
}
return true;
}
int main(int argc, char **argv)
@ -643,9 +472,6 @@ int main(int argc, char **argv)
}
s = g_malloc0(sizeof(GAState));
s->conn_channel = NULL;
s->path = path;
s->method = method;
s->log_file = log_file;
s->log_level = log_level;
g_log_set_default_handler(ga_log, s);
@ -654,15 +480,31 @@ int main(int argc, char **argv)
s->command_state = ga_command_state_new();
ga_command_state_init(s, s->command_state);
ga_command_state_init_all(s->command_state);
json_message_parser_init(&s->parser, process_event);
ga_state = s;
if (!register_signal_handlers()) {
g_critical("failed to register signal handlers");
goto out_bad;
}
init_guest_agent(ga_state);
register_signal_handlers();
s->main_loop = g_main_loop_new(NULL, false);
if (!channel_init(ga_state, method, path)) {
g_critical("failed to initialize guest agent channel");
goto out_bad;
}
g_main_loop_run(ga_state->main_loop);
ga_command_state_cleanup_all(ga_state->command_state);
unlink(pidfile);
ga_channel_free(ga_state->channel);
if (daemonize) {
unlink(pidfile);
}
return 0;
out_bad:
if (daemonize) {
unlink(pidfile);
}
return EXIT_FAILURE;
}

246
qga/channel-posix.c Normal file
View File

@ -0,0 +1,246 @@
#include <glib.h>
#include <termios.h>
#include "qemu_socket.h"
#include "qga/channel.h"
#define GA_CHANNEL_BAUDRATE_DEFAULT B38400 /* for isa-serial channels */
struct GAChannel {
GIOChannel *listen_channel;
GIOChannel *client_channel;
GAChannelMethod method;
GAChannelCallback event_cb;
gpointer user_data;
};
static int ga_channel_client_add(GAChannel *c, int fd);
static gboolean ga_channel_listen_accept(GIOChannel *channel,
GIOCondition condition, gpointer data)
{
GAChannel *c = data;
int ret, client_fd;
bool accepted = false;
struct sockaddr_un addr;
socklen_t addrlen = sizeof(addr);
g_assert(channel != NULL);
client_fd = qemu_accept(g_io_channel_unix_get_fd(channel),
(struct sockaddr *)&addr, &addrlen);
if (client_fd == -1) {
g_warning("error converting fd to gsocket: %s", strerror(errno));
goto out;
}
fcntl(client_fd, F_SETFL, O_NONBLOCK);
ret = ga_channel_client_add(c, client_fd);
if (ret) {
g_warning("error setting up connection");
goto out;
}
accepted = true;
out:
/* only accept 1 connection at a time */
return !accepted;
}
/* start polling for readable events on listen fd, new==true
* indicates we should use the existing s->listen_channel
*/
static void ga_channel_listen_add(GAChannel *c, int listen_fd, bool create)
{
if (create) {
c->listen_channel = g_io_channel_unix_new(listen_fd);
}
g_io_add_watch(c->listen_channel, G_IO_IN, ga_channel_listen_accept, c);
}
static void ga_channel_listen_close(GAChannel *c)
{
g_assert(c->method == GA_CHANNEL_UNIX_LISTEN);
g_assert(c->listen_channel);
g_io_channel_shutdown(c->listen_channel, true, NULL);
g_io_channel_unref(c->listen_channel);
c->listen_channel = NULL;
}
/* cleanup state for closed connection/session, start accepting new
* connections if we're in listening mode
*/
static void ga_channel_client_close(GAChannel *c)
{
g_assert(c->client_channel);
g_io_channel_shutdown(c->client_channel, true, NULL);
g_io_channel_unref(c->client_channel);
c->client_channel = NULL;
if (c->method == GA_CHANNEL_UNIX_LISTEN && c->listen_channel) {
ga_channel_listen_add(c, 0, false);
}
}
static gboolean ga_channel_client_event(GIOChannel *channel,
GIOCondition condition, gpointer data)
{
GAChannel *c = data;
gboolean client_cont;
g_assert(c);
if (c->event_cb) {
client_cont = c->event_cb(condition, c->user_data);
if (!client_cont) {
ga_channel_client_close(c);
return false;
}
}
return true;
}
static int ga_channel_client_add(GAChannel *c, int fd)
{
GIOChannel *client_channel;
GError *err = NULL;
g_assert(c && !c->client_channel);
client_channel = g_io_channel_unix_new(fd);
g_assert(client_channel);
g_io_channel_set_encoding(client_channel, NULL, &err);
if (err != NULL) {
g_warning("error setting channel encoding to binary");
g_error_free(err);
return -1;
}
g_io_add_watch(client_channel, G_IO_IN | G_IO_HUP,
ga_channel_client_event, c);
c->client_channel = client_channel;
return 0;
}
static gboolean ga_channel_open(GAChannel *c, const gchar *path, GAChannelMethod method)
{
int ret;
c->method = method;
switch (c->method) {
case GA_CHANNEL_VIRTIO_SERIAL: {
int fd = qemu_open(path, O_RDWR | O_NONBLOCK | O_ASYNC);
if (fd == -1) {
g_critical("error opening channel: %s", strerror(errno));
exit(EXIT_FAILURE);
}
ret = ga_channel_client_add(c, fd);
if (ret) {
g_critical("error adding channel to main loop");
return false;
}
break;
}
case GA_CHANNEL_ISA_SERIAL: {
struct termios tio;
int fd = qemu_open(path, O_RDWR | O_NOCTTY | O_NONBLOCK);
if (fd == -1) {
g_critical("error opening channel: %s", strerror(errno));
exit(EXIT_FAILURE);
}
tcgetattr(fd, &tio);
/* set up serial port for non-canonical, dumb byte streaming */
tio.c_iflag &= ~(IGNBRK | BRKINT | IGNPAR | PARMRK | INPCK | ISTRIP |
INLCR | IGNCR | ICRNL | IXON | IXOFF | IXANY |
IMAXBEL);
tio.c_oflag = 0;
tio.c_lflag = 0;
tio.c_cflag |= GA_CHANNEL_BAUDRATE_DEFAULT;
/* 1 available byte min or reads will block (we'll set non-blocking
* elsewhere, else we have to deal with read()=0 instead)
*/
tio.c_cc[VMIN] = 1;
tio.c_cc[VTIME] = 0;
/* flush everything waiting for read/xmit, it's garbage at this point */
tcflush(fd, TCIFLUSH);
tcsetattr(fd, TCSANOW, &tio);
ret = ga_channel_client_add(c, fd);
if (ret) {
g_error("error adding channel to main loop");
}
break;
}
case GA_CHANNEL_UNIX_LISTEN: {
int fd = unix_listen(path, NULL, strlen(path));
if (fd == -1) {
g_critical("error opening path: %s", strerror(errno));
return false;
}
ga_channel_listen_add(c, fd, true);
break;
}
default:
g_critical("error binding/listening to specified socket");
return false;
}
return true;
}
GIOStatus ga_channel_write_all(GAChannel *c, const gchar *buf, gsize size)
{
GError *err = NULL;
gsize written = 0;
GIOStatus status = G_IO_STATUS_NORMAL;
while (size) {
status = g_io_channel_write_chars(c->client_channel, buf, size,
&written, &err);
g_debug("sending data, count: %d", (int)size);
if (err != NULL) {
g_warning("error writing to channel: %s", err->message);
return G_IO_STATUS_ERROR;
}
if (status != G_IO_STATUS_NORMAL) {
break;
}
size -= written;
}
if (status == G_IO_STATUS_NORMAL) {
status = g_io_channel_flush(c->client_channel, &err);
if (err != NULL) {
g_warning("error flushing channel: %s", err->message);
return G_IO_STATUS_ERROR;
}
}
return status;
}
GIOStatus ga_channel_read(GAChannel *c, gchar *buf, gsize size, gsize *count)
{
return g_io_channel_read_chars(c->client_channel, buf, size, count, NULL);
}
GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path,
GAChannelCallback cb, gpointer opaque)
{
GAChannel *c = g_malloc0(sizeof(GAChannel));
c->event_cb = cb;
c->user_data = opaque;
if (!ga_channel_open(c, path, method)) {
g_critical("error opening channel");
ga_channel_free(c);
return NULL;
}
return c;
}
void ga_channel_free(GAChannel *c)
{
if (c->method == GA_CHANNEL_UNIX_LISTEN
&& c->listen_channel) {
ga_channel_listen_close(c);
}
if (c->client_channel) {
ga_channel_client_close(c);
}
g_free(c);
}

33
qga/channel.h Normal file
View File

@ -0,0 +1,33 @@
/*
* QEMU Guest Agent channel declarations
*
* Copyright IBM Corp. 2012
*
* Authors:
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef QGA_CHANNEL_H
#define QGA_CHANNEL_H
#include <glib.h>
typedef struct GAChannel GAChannel;
typedef enum {
GA_CHANNEL_VIRTIO_SERIAL,
GA_CHANNEL_ISA_SERIAL,
GA_CHANNEL_UNIX_LISTEN,
} GAChannelMethod;
typedef gboolean (*GAChannelCallback)(GIOCondition condition, gpointer opaque);
GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path,
GAChannelCallback cb, gpointer opaque);
void ga_channel_free(GAChannel *c);
GIOStatus ga_channel_read(GAChannel *c, gchar *buf, gsize size, gsize *count);
GIOStatus ga_channel_write_all(GAChannel *c, const gchar *buf, gsize size);
#endif

2
qga/guest-agent-core.h
View File

@ -14,7 +14,7 @@
#include "qemu-common.h"
#define QGA_VERSION "1.0"
#define QGA_READ_COUNT_DEFAULT 4 << 10
#define QGA_READ_COUNT_DEFAULT 4096
typedef struct GAState GAState;
typedef struct GACommandState GACommandState;