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Re: [Qemu-devel] [PATCH v5 2/5] guest agent: qemu-ga daemon


From: Luiz Capitulino
Subject: Re: [Qemu-devel] [PATCH v5 2/5] guest agent: qemu-ga daemon
Date: Fri, 17 Jun 2011 17:13:01 -0300

On Fri, 17 Jun 2011 14:21:31 -0500
Michael Roth <address@hidden> wrote:

> On 06/16/2011 01:42 PM, Luiz Capitulino wrote:
> > On Tue, 14 Jun 2011 15:06:22 -0500
> > Michael Roth<address@hidden>  wrote:
> >
> >> This is the actual guest daemon, it listens for requests over a
> >> virtio-serial/isa-serial/unix socket channel and routes them through
> >> to dispatch routines, and writes the results back to the channel in
> >> a manner similar to QMP.
> >>
> >> A shorthand invocation:
> >>
> >>    qemu-ga -d
> >>
> >> Is equivalent to:
> >>
> >>    qemu-ga -c virtio-serial -p /dev/virtio-ports/org.qemu.guest_agent \
> >>            -p /var/run/qemu-guest-agent.pid -d
> >>
> >> Signed-off-by: Michael Roth<address@hidden>
> >
> > Would be nice to have a more complete description, like explaining how to
> > do a simple test.
> >
> > And this can't be built...
> >
> >> ---
> >>   qemu-ga.c              |  631 
> >> ++++++++++++++++++++++++++++++++++++++++++++++++
> >>   qga/guest-agent-core.h |    4 +
> >>   2 files changed, 635 insertions(+), 0 deletions(-)
> >>   create mode 100644 qemu-ga.c
> >>
> >> diff --git a/qemu-ga.c b/qemu-ga.c
> >> new file mode 100644
> >> index 0000000..df08d8c
> >> --- /dev/null
> >> +++ b/qemu-ga.c
> >> @@ -0,0 +1,631 @@
> >> +/*
> >> + * QEMU Guest Agent
> >> + *
> >> + * Copyright IBM Corp. 2011
> >> + *
> >> + * Authors:
> >> + *  Adam Litke<address@hidden>
> >> + *  Michael Roth<address@hidden>
> >> + *
> >> + * This work is licensed under the terms of the GNU GPL, version 2 or 
> >> later.
> >> + * See the COPYING file in the top-level directory.
> >> + */
> >> +#include<stdlib.h>
> >> +#include<stdio.h>
> >> +#include<stdbool.h>
> >> +#include<glib.h>
> >> +#include<gio/gio.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"
> >> +#include "qjson.h"
> >> +#include "qga/guest-agent-core.h"
> >> +#include "qga-qmp-commands.h"
> >> +#include "module.h"
> >> +
> >> +#define QGA_VIRTIO_PATH_DEFAULT "/dev/virtio-ports/org.qemu.guest_agent"
> >> +#define QGA_PIDFILE_DEFAULT "/var/run/qemu-va.pid"
> >> +#define QGA_BAUDRATE_DEFAULT B38400 /* for isa-serial channels */
> >> +#define QGA_TIMEOUT_DEFAULT 30*1000 /* ms */
> >> +
> >> +struct GAState {
> >> +    const char *proxy_path;
> >
> > Where is this used?
> >
> 
> Nowhere actually. Will remove.
> 
> >> +    JSONMessageParser parser;
> >> +    GMainLoop *main_loop;
> >> +    guint conn_id;
> >> +    GSocket *conn_sock;
> >> +    GIOChannel *conn_channel;
> >> +    guint listen_id;
> >> +    GSocket *listen_sock;
> >> +    GIOChannel *listen_channel;
> >> +    const char *path;
> >> +    const char *method;
> >> +    bool virtio; /* fastpath to check for virtio to deal with poll() 
> >> quirks */
> >> +    GACommandState *command_state;
> >> +    GLogLevelFlags log_level;
> >> +    FILE *log_file;
> >> +    bool logging_enabled;
> >> +};
> >> +
> >> +static void usage(const char *cmd)
> >> +{
> >> +    printf(
> >> +"Usage: %s -c<channel_opts>\n"
> >> +"QEMU Guest Agent %s\n"
> >> +"\n"
> >> +"  -c, --channel     channel method: one of unix-connect, virtio-serial, 
> >> or\n"
> >> +"                    isa-serial (virtio-serial is the default)\n"
> >> +"  -p, --path        channel path (%s is the default for virtio-serial)\n"
> >> +"  -l, --logfile     set logfile path, logs to stderr by default\n"
> >> +"  -f, --pidfile     specify pidfile (default is %s)\n"
> >> +"  -v, --verbose     log extra debugging information\n"
> >> +"  -V, --version     print version information and exit\n"
> >> +"  -d, --daemonize   become a daemon\n"
> >> +"  -h, --help        display this help and exit\n"
> >> +"\n"
> >> +"Report bugs to<address@hidden>\n"
> >> +    , 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) {
> >> +        case G_LOG_LEVEL_ERROR:
> >> +            return "error";
> >> +        case G_LOG_LEVEL_CRITICAL:
> >> +            return "critical";
> >> +        case G_LOG_LEVEL_WARNING:
> >> +            return "warning";
> >> +        case G_LOG_LEVEL_MESSAGE:
> >> +            return "message";
> >> +        case G_LOG_LEVEL_INFO:
> >> +            return "info";
> >> +        case G_LOG_LEVEL_DEBUG:
> >> +            return "debug";
> >> +        default:
> >> +            return "user";
> >> +    }
> >> +}
> >> +
> >> +bool ga_logging_enabled(GAState *s)
> >> +{
> >> +    return s->logging_enabled;
> >> +}
> >> +
> >> +void ga_disable_logging(GAState *s)
> >> +{
> >> +    s->logging_enabled = false;
> >> +}
> >> +
> >> +void ga_enable_logging(GAState *s)
> >> +{
> >> +    s->logging_enabled = true;
> >> +}
> >
> > Just to check I got this right, this is needed because of the fsfreeze
> > command, correct? Isn't it better to have a more descriptive name, like
> > fsfrozen?
> >
> > First I thought this was about a log file. Then I realized this was
> > probably about letting the user log in, but we don't seem to have this
> > functionality so I got confused.
> >
> 
> Yup, this is currently due to fsfreeze support. From the perspective of 
> the fsfreeze command the explicit "is_frozen" check makes more sense, 
> but the reason it affects other RPCs is because because we can't log 
> stuff in that state. If an RPC shoots itself in the foot by writing to a 
> frozen filesystem we don't really care so much, and up until recently 
> that case was handled with a pthread_cancel timeout mechanism (was 
> removed for the time being, will re-implement using a child process most 
> likely).
> 
> What we don't want to do is give a host a way to bypass the expectation 
> we set for guest owners by allowing RPCs to be logged. So that's what 
> the check is based on, rather than lower level details like *why* 
> logging is disabled. Also, I'd really like to avoid a precedence where a 
> single RPC can place restrictions on all the others, so the logging 
> aspect seemed general enough that it doesn't necessarily provide that 
> precedence.
> 
> This has come up a few times without any real consensus. I can probably 
> go either way, but I think the check for logging is easier to set 
> expectations with: "if logging is important from an auditing 
> perspective, don't execute this if logging is disabled". beyond that, 
> same behavior/symantics you'd get with anything that causes a write() on 
> a filesystem in a frozen state: block.

While I understand your arguments, I still find the current behavior
confusing: you issue a guest-open-file command and get a QgaLoggingFailed
error. The first question is: what does a log write fail have to do with me
opening a file? The second question is: what should I do? Try again? Give up?

IMHO, making fsfrozen a global state makes more sense. It's the true guest
state after all. This way a client will clearly know what's happening and
what it has to do in order to make its command successful.

Another possible solution is to have the same semantics of a non-blocking
I/O, that's, return EWOULDBLOCK. I find this less confusing than the
current error.

> 
> >> +
> >> +static void ga_log(const gchar *domain, GLogLevelFlags level,
> >> +                   const gchar *msg, gpointer opaque)
> >> +{
> >> +    GAState *s = opaque;
> >> +    GTimeVal time;
> >> +    const char *level_str = ga_log_level_str(level);
> >> +
> >> +    if (!ga_logging_enabled(s)) {
> >> +        return;
> >> +    }
> >> +
> >> +    level&= G_LOG_LEVEL_MASK;
> >> +    if (g_strcmp0(domain, "syslog") == 0) {
> >> +        syslog(LOG_INFO, "%s: %s", level_str, msg);
> >> +    } else if (level&  s->log_level) {
> >> +        g_get_current_time(&time);
> >> +        fprintf(s->log_file,
> >> +                "%lu.%lu: %s: %s\n", time.tv_sec, time.tv_usec, 
> >> level_str, msg);
> >> +        fflush(s->log_file);
> >> +    }
> >> +}
> >> +
> >> +static void become_daemon(const char *pidfile)
> >> +{
> >> +    pid_t pid, sid;
> >> +    int pidfd;
> >> +    char *pidstr = NULL;
> >> +
> >> +    pid = fork();
> >> +    if (pid<  0) {
> >> +        exit(EXIT_FAILURE);
> >> +    }
> >> +    if (pid>  0) {
> >> +        exit(EXIT_SUCCESS);
> >> +    }
> >> +
> >> +    pidfd = open(pidfile, O_CREAT|O_RDWR, S_IRUSR|S_IWUSR);
> >
> > O_WRONLY is enough.
> >
> >> +    if (!pidfd || lockf(pidfd, F_TLOCK, 0)) {
> >> +        g_error("Cannot lock pid file");
> >> +    }
> >
> > Are you sure we need lockf() here? I think using O_EXCL is enough for
> > pid files.
> >
> 
> O_EXCL + O_CREAT? Wouldn't we have issues if the pid file wasn't cleaned 
> up from a previous run?

Yes, but that's the intention (and that's how most daemons work afaik). The
only reason for a daemon not to cleanup its pid file is when it exists
abnormally. If this happens, then only the sysadmin can ensure that it's safe
to run another daemon instance.

We could add a -r (--override-existing-pid-file) option, but we should not
do it silently.

Btw, we need to implement a signal handler for SIGTERM.

> >> +
> >> +    if (ftruncate(pidfd, 0) || lseek(pidfd, 0, SEEK_SET)) {
> >> +        g_critical("Cannot truncate pid file");
> >> +        goto fail;
> >
> > You can use O_TRUNC and the file pointer is already positioned at the
> > beginning of the file, no need to call lseek().
> >
> >> +    }
> >> +    if (asprintf(&pidstr, "%d", getpid()) == -1) {
> >> +        g_critical("Cannot allocate memory");
> >> +        goto fail;
> >> +    }
> >> +    if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
> >> +        g_critical("Failed to write pid file");
> >> +        goto fail;
> >> +    }
> >
> > You're not freeing pidstr, nor closing the file (although I think you
> > do this because of the lockf() call()).
> >
> 
> pidstr gets free'd in the fail: block. And yeah, closing would give up 
> the lock prematurely.

pidstr leaks on a successful execution.

> 
> >> +
> >> +    umask(0);
> >> +    sid = setsid();
> >> +    if (sid<  0) {
> >> +        goto fail;
> >> +    }
> >> +    if ((chdir("/"))<  0) {
> >> +        goto fail;
> >> +    }
> >> +
> >> +    close(STDIN_FILENO);
> >> +    close(STDOUT_FILENO);
> >> +    close(STDERR_FILENO);
> >> +    return;
> >> +
> >> +fail:
> >> +    if (pidstr) {
> >> +        free(pidstr);
> >> +    }
> >
> > This check is not needed.
> >
> >> +    unlink(pidfile);
> >> +    g_error("failed to daemonize");
> >> +}
> >> +
> >> +static int conn_channel_send_payload(GIOChannel *channel, QObject 
> >> *payload)
> >> +{
> >> +    gsize count, written = 0;
> >> +    int ret;
> >> +    const char *buf;
> >> +    QString *payload_qstr;
> >> +    GIOStatus status;
> >> +    GError *err = NULL;
> >> +
> >> +    if (!payload || !channel) {
> >> +        ret = -EINVAL;
> >> +        goto out;
> >> +    }
> >
> > Just do "return -EINVAL" instead of using goto, but I wonder if this should
> > be an assert() instead.
> >
> 
> Yah, looks like it.
> 
> >> +
> >> +    payload_qstr = qobject_to_json(payload);
> >> +    if (!payload_qstr) {
> >> +        ret = -EINVAL;
> >> +        goto out;
> >> +    }
> >
> > return -EINVAL.
> >
> >> +
> >> +    buf = qstring_get_str(payload_qstr);
> >> +    count = strlen(buf);
> >> +
> >> +    while (count) {
> >> +        g_debug("sending data, count: %d", (int)count);
> >> +        status = g_io_channel_write_chars(channel, buf, 
> >> count,&written,&err);
> >> +        if (err != NULL) {
> >> +            g_warning("error writing payload to channel: %s", 
> >> err->message);
> >> +            ret = err->code;
> >> +            goto out_free;
> >> +        }
> >> +        if (status == G_IO_STATUS_NORMAL) {
> >> +            count -= written;
> >> +        } else if (status == G_IO_STATUS_ERROR || status == 
> >> G_IO_STATUS_EOF) {
> >> +            ret = -EPIPE;
> >> +            goto out_free;
> >> +        }
> >> +    }
> >> +
> >> +    status = g_io_channel_write_chars(channel, (char *)"\n", 
> >> 1,&written,&err);
> >> +    if (err != NULL) {
> >> +        g_warning("error sending newline: %s", err->message);
> >> +        ret = err->code;
> >> +        goto out_free;
> >> +    } else if (status == G_IO_STATUS_ERROR || status == G_IO_STATUS_EOF) {
> >> +        ret = -EPIPE;
> >> +        goto out_free;
> >> +    }
> >
> > This wants to be a function.
> >
> >> +
> >> +    g_io_channel_flush(channel,&err);
> >> +    if (err != NULL) {
> >> +        g_warning("error flushing payload: %s", err->message);
> >> +        ret = err->code;
> >> +        goto out_free;
> >> +    }
> >> +
> >> +    ret = 0;
> >> +
> >> +out_free:
> >> +    QDECREF(payload_qstr);
> >> +    if (err != NULL) {
> >> +        g_error_free(err);
> >> +    }
> >
> > No need to check against NULL.
> >
> >> +out:
> >> +    return ret;
> >> +}
> >> +
> >> +static void process_command(GAState *s, QDict *req)
> >> +{
> >> +    QObject *rsp = NULL;
> >> +    Error *err = NULL;
> >> +    int ret;
> >> +
> >> +    g_assert(req);
> >> +    g_debug("processing command");
> >> +    rsp = qmp_dispatch(QOBJECT(req));
> >> +    if (rsp) {
> >> +        if (err) {
> >
> > Apart from its initialization, 'err' is read only. Either, you want to
> > use qmp_dispatch_err() here or you have to modify qmp_dispatch() to also
> > accept an Error argument.
> >
> > If you want to send a "return" or "error" QMP kind of response, then you
> > have to do the latter.
> >
> 
> qmp_dispatch() does the Error -> QMP error conversion. The unused err is 
> cruft from when a seperate worker thread did the dispatch, will remove it.
> 
> >> +            g_warning("command failed: %s", error_get_pretty(err));
> >> +        }
> >> +        ret = conn_channel_send_payload(s->conn_channel, rsp);
> >> +        if (ret) {
> >> +            g_warning("error sending payload: %s", strerror(ret));
> >> +        }
> >> +        qobject_decref(rsp);
> >> +    } else {
> >> +        g_warning("error getting response");
> >> +        if (err) {
> >> +            g_warning("dispatch failed: %s", error_get_pretty(err));
> >> +        }
> >> +    }
> >> +}
> >> +
> >> +/* handle requests/control events coming in over the channel */
> >> +static void process_event(JSONMessageParser *parser, QList *tokens)
> >> +{
> >> +    GAState *s = container_of(parser, GAState, parser);
> >> +    QObject *obj;
> >> +    QDict *qdict;
> >> +    Error *err = NULL;
> >> +
> >> +    g_assert(s&&  parser);
> >> +
> >> +    g_debug("process_event: called");
> >> +    obj = json_parser_parse_err(tokens, NULL,&err);
> >> +    if (!obj || qobject_type(obj) != QTYPE_QDICT) {
> >> +        g_warning("failed to parse event");
> >
> > Two possible leaks here. You have to call qobject_decref() if obj != NULL
> > and there's a missing call to error_free(). But you don't use 'err' anyway,
> > so you could pass NULL there.
> >
> > Oh, btw, the guest agent doesn't seem to report errors back to its client...
> > Not even json error messages, is this intended?
> >
> 
> Hmm, yes it's intended, but I probably should send those to the client...
> 
> You do get non-parse errors though: missing arguments, etc.
> 
> I'll fix this to do what QMP does here.
> 
> >> +        return;
> >> +    } else {
> >> +        g_debug("parse successful");
> >> +        qdict = qobject_to_qdict(obj);
> >> +        g_assert(qdict);
> >> +    }
> >
> > Superfluous else clause.
> >
> >> +
> >> +    /* handle host->guest commands */
> >> +    if (qdict_haskey(qdict, "execute")) {
> >> +        process_command(s, qdict);
> >> +    } else {
> >> +        g_warning("unrecognized payload format, ignoring");
> >> +    }
> >> +
> >> +    QDECREF(qdict);
> >> +}
> >> +
> >> +static gboolean conn_channel_read(GIOChannel *channel, GIOCondition 
> >> condition,
> >> +                                  gpointer data)
> >> +{
> >> +    GAState *s = data;
> >> +    gchar buf[1024];
> >> +    gsize count;
> >> +    GError *err = NULL;
> >> +    memset(buf, 0, 1024);
> >> +    GIOStatus status = g_io_channel_read_chars(channel, buf, 1024,
> >> +&count,&err);
> >> +    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");
> >> +        return false;
> >> +    case G_IO_STATUS_NORMAL:
> >> +        g_debug("read data, count: %d, data: %s", (int)count, buf);
> >> +        json_message_parser_feed(&s->parser, (char *)buf, (int)count);
> >> +    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
> >> +         */
> >> +        if (s->virtio) {
> >> +            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)
> >> +{
> >> +    GIOChannel *conn_channel;
> >> +    guint conn_id;
> >> +    GError *err = NULL;
> >> +
> >> +    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;
> >> +    }
> >> +    conn_id = g_io_add_watch(conn_channel, G_IO_IN | G_IO_HUP,
> >> +                             conn_channel_read, s);
> >> +    if (err != NULL) {
> >> +        g_warning("error adding io watch: %s", err->message);
> >> +        g_error_free(err);
> >> +        return -1;
> >> +    }
> >> +    s->conn_channel = conn_channel;
> >> +    s->conn_id = conn_id;
> >> +    return 0;
> >> +}
> >> +
> >> +static gboolean listen_channel_accept(GIOChannel *channel,
> >> +                                      GIOCondition condition, gpointer 
> >> data)
> >> +{
> >> +    GAState *s = data;
> >> +    GError *err = NULL;
> >> +    g_assert(channel != NULL);
> >> +    int ret;
> >> +    bool accepted = false;
> >> +
> >> +    s->conn_sock = g_socket_accept(s->listen_sock, NULL,&err);
> >> +    if (err != NULL) {
> >> +        g_warning("error converting fd to gsocket: %s", err->message);
> >> +        g_error_free(err);
> >> +        goto out;
> >> +    }
> >> +    ret = conn_channel_add(s, g_socket_get_fd(s->conn_sock));
> >> +    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, listen_fd=0
> >> + * indicates we should use the existing s->listen_channel
> >> + */
> >> +static int listen_channel_add(GAState *s, int listen_fd)
> >> +{
> >> +    GError *err = NULL;
> >> +    guint listen_id;
> >> +
> >> +    if (listen_fd) {
> >> +        s->listen_channel = g_io_channel_unix_new(listen_fd);
> >> +        if (s->listen_sock) {
> >> +            g_object_unref(s->listen_sock);
> >> +        }
> >> +        s->listen_sock = g_socket_new_from_fd(listen_fd,&err);
> >> +        if (err != NULL) {
> >> +            g_warning("error converting fd to gsocket: %s", err->message);
> >> +            g_error_free(err);
> >> +            return -1;
> >> +        }
> >> +    }
> >> +    listen_id = g_io_add_watch(s->listen_channel, G_IO_IN,
> >> +                               listen_channel_accept, s);
> >> +    if (err != NULL) {
> >> +        g_warning("error adding io watch: %s", err->message);
> >> +        g_error_free(err);
> >> +        return -1;
> >> +    }
> >> +    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);
> >> +        g_object_unref(s->conn_sock);
> >> +        s->conn_sock = NULL;
> >> +        listen_channel_add(s, 0);
> >> +    } 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;
> >> +    s->conn_id = 0;
> >> +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 (s->path == NULL) {
> >> +        if (strcmp(s->method, "virtio-serial") != 0) {
> >> +            g_error("must specify a path for this channel");
> >> +        }
> >> +        /* try the default path for the virtio-serial port */
> >> +        s->path = QGA_VIRTIO_PATH_DEFAULT;
> >> +    }
> >> +
> >> +    if (strcmp(s->method, "virtio-serial") == 0) {
> >> +        s->virtio = true;
> >> +        fd = qemu_open(s->path, O_RDWR);
> >> +        if (fd == -1) {
> >> +            g_error("error opening channel: %s", strerror(errno));
> >> +        }
> >> +        ret = fcntl(fd, F_GETFL);
> >> +        if (ret<  0) {
> >> +            g_error("error getting channel flags: %s", strerror(errno));
> >> +        }
> >> +        ret = fcntl(fd, F_SETFL, ret | O_NONBLOCK | O_ASYNC);
> >> +        if (ret<  0) {
> >> +            g_error("error setting channel flags: %s", strerror(errno));
> >> +        }
> >> +        ret = conn_channel_add(s, fd);
> >> +        if (ret) {
> >> +            g_error("error adding channel to main loop");
> >> +        }
> >> +    } else if (strcmp(s->method, "isa-serial") == 0) {
> >> +        fd = qemu_open(s->path, O_RDWR | O_NOCTTY);
> >> +        if (fd == -1) {
> >> +            g_error("error opening channel: %s", strerror(errno));
> >> +        }
> >> +        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_error("error opening path: %s", strerror(errno));
> >> +        }
> >> +        ret = listen_channel_add(s, fd);
> >> +        if (ret) {
> >> +            g_error("error binding/listening to specified socket");
> >> +        }
> >> +    } else {
> >> +        g_error("unsupported channel method/type: %s", s->method);
> >> +    }
> >> +
> >> +    json_message_parser_init(&s->parser, process_event);
> >> +    s->main_loop = g_main_loop_new(NULL, false);
> >> +}
> >> +
> >> +int main(int argc, char **argv)
> >> +{
> >> +    const char *sopt = "hVvdc:p:l:f:";
> >> +    const char *method = NULL, *path = NULL, *pidfile = 
> >> QGA_PIDFILE_DEFAULT;
> >> +    struct option lopt[] = {
> >> +        { "help", 0, NULL, 'h' },
> >> +        { "version", 0, NULL, 'V' },
> >> +        { "logfile", 0, NULL, 'l' },
> >> +        { "pidfile", 0, NULL, 'f' },
> >> +        { "verbose", 0, NULL, 'v' },
> >> +        { "channel", 0, NULL, 'c' },
> >> +        { "path", 0, NULL, 'p' },
> >> +        { "daemonize", 0, NULL, 'd' },
> >> +        { NULL, 0, NULL, 0 }
> >> +    };
> >> +    int opt_ind = 0, ch, daemonize = 0;
> >> +    GLogLevelFlags log_level = G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL;
> >> +    FILE *log_file = stderr;
> >> +    GAState *s;
> >> +
> >> +    g_type_init();
> >> +    g_thread_init(NULL);
> >> +
> >> +    while ((ch = getopt_long(argc, argv, sopt, lopt,&opt_ind)) != -1) {
> >> +        switch (ch) {
> >> +        case 'c':
> >> +            method = optarg;
> >> +            break;
> >> +        case 'p':
> >> +            path = optarg;
> >> +            break;
> >> +        case 'l':
> >> +            log_file = fopen(optarg, "a");
> >> +            if (!log_file) {
> >> +                g_error("unable to open specified log file: %s",
> >> +                        strerror(errno));
> >> +            }
> >> +            break;
> >> +        case 'f':
> >> +            pidfile = optarg;
> >> +            break;
> >> +        case 'v':
> >> +            /* enable all log levels */
> >> +            log_level = G_LOG_LEVEL_MASK;
> >> +            break;
> >> +        case 'V':
> >> +            printf("QEMU Guest Agent %s\n", QGA_VERSION);
> >> +            return 0;
> >> +        case 'd':
> >> +            daemonize = 1;
> >> +            break;
> >> +        case 'h':
> >> +            usage(argv[0]);
> >> +            return 0;
> >> +        case '?':
> >> +            g_error("Unknown option, try '%s --help' for more 
> >> information.",
> >> +                    argv[0]);
> >> +        }
> >> +    }
> >> +
> >> +    if (daemonize) {
> >> +        g_debug("starting daemon");
> >> +        become_daemon(pidfile);
> >> +    }
> >> +
> >> +    s = g_malloc0(sizeof(GAState));
> >> +    s->conn_id = 0;
> >> +    s->conn_channel = NULL;
> >> +    s->path = path;
> >> +    s->method = method;
> >> +    s->command_state = ga_command_state_new();
> >> +    ga_command_state_init(s, s->command_state);
> >> +    ga_command_state_init_all(s->command_state);
> >> +    s->log_file = log_file;
> >> +    s->log_level = log_level;
> >> +    g_log_set_default_handler(ga_log, s);
> >> +    g_log_set_fatal_mask(NULL, G_LOG_LEVEL_ERROR);
> >> +    s->logging_enabled = true;
> >> +
> >> +    module_call_init(MODULE_INIT_QAPI);
> >> +    init_guest_agent(s);
> >> +
> >> +    g_main_loop_run(s->main_loop);
> >> +
> >> +    ga_command_state_cleanup_all(s->command_state);
> >> +
> >> +    return 0;
> >> +}
> >> diff --git a/qga/guest-agent-core.h b/qga/guest-agent-core.h
> >> index 688f120..66d1729 100644
> >> --- a/qga/guest-agent-core.h
> >> +++ b/qga/guest-agent-core.h
> >
> > No license text.
> >
> >> @@ -15,6 +15,7 @@
> >>
> >>   #define QGA_VERSION "1.0"
> >>
> >> +typedef struct GAState GAState;
> >>   typedef struct GACommandState GACommandState;
> >>
> >>   void ga_command_state_add(GACommandState *cs,
> >> @@ -23,3 +24,6 @@ void ga_command_state_add(GACommandState *cs,
> >>   void ga_command_state_init_all(GACommandState *cs);
> >>   void ga_command_state_cleanup_all(GACommandState *cs);
> >>   GACommandState *ga_command_state_new(void);
> >> +bool ga_logging_enabled(GAState *s);
> >> +void ga_disable_logging(GAState *s);
> >> +void ga_enable_logging(GAState *s);
> >
> 




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