qga/channel-win32.c - qemu - Git at Google

 #include "qemu/osdep.h"
 #include <windows.h>
 #include <io.h>
 #include "guest-agent-core.h"
 #include "channel.h"

 typedef struct GAChannelReadState {
     guint thread_id;
     uint8_t *buf;
     size_t buf_size;
     size_t cur; /* current buffer start */
     size_t pending; /* pending buffered bytes to read */
     OVERLAPPED ov;
     bool ov_pending; /* whether on async read is outstanding */
 } GAChannelReadState;

 struct GAChannel {
     HANDLE handle;
     GAChannelCallback cb;
     gpointer user_data;
     GAChannelReadState rstate;
     GIOCondition pending_events; /* TODO: use GAWatch.pollfd.revents */
     GSource *source;
 };

 typedef struct GAWatch {
     GSource source;
     GPollFD pollfd;
     GAChannel *channel;
     GIOCondition events_mask;
 } GAWatch;

 /*
  * Called by glib prior to polling to set up poll events if polling is needed.
  *
  */
 static gboolean ga_channel_prepare(GSource *source, gint *timeout_ms)
 {
     GAWatch *watch = (GAWatch *)source;
     GAChannel *c = (GAChannel *)watch->channel;
     GAChannelReadState *rs = &c->rstate;
     DWORD count_read, count_to_read = 0;
     bool success;
     GIOCondition new_events = 0;

     g_debug("prepare");
     /* go ahead and submit another read if there's room in the buffer
      * and no previous reads are outstanding
      */
     if (!rs->ov_pending) {
         if (rs->cur + rs->pending >= rs->buf_size) {
             if (rs->cur) {
                 memmove(rs->buf, rs->buf + rs->cur, rs->pending);
                 rs->cur = 0;
             }
         }
         count_to_read = rs->buf_size - rs->cur - rs->pending;
     }

     if (rs->ov_pending || count_to_read <= 0) {
             goto out;
     }

     /* submit the read */
     success = ReadFile(c->handle, rs->buf + rs->cur + rs->pending,
                        count_to_read, &count_read, &rs->ov);
     if (success) {
         rs->pending += count_read;
         rs->ov_pending = false;
     } else {
         if (GetLastError() == ERROR_IO_PENDING) {
             rs->ov_pending = true;
         } else {
             new_events |= G_IO_ERR;
         }
     }

 out:
     /* don't block forever, iterate the main loop every once in a while */
     *timeout_ms = 500;
     /* if there's data in the read buffer, or another event is pending,
      * skip polling and issue user cb.
      */
     if (rs->pending) {
         new_events |= G_IO_IN;
     }
     c->pending_events |= new_events;
     return !!c->pending_events;
 }

 /*
  * Called by glib after an outstanding read request is completed.
  */
 static gboolean ga_channel_check(GSource *source)
 {
     GAWatch *watch = (GAWatch *)source;
     GAChannel *c = (GAChannel *)watch->channel;
     GAChannelReadState *rs = &c->rstate;
     DWORD count_read, error;
     BOOL success;

     GIOCondition new_events = 0;

     g_debug("check");

     /* failing this implies we issued a read that completed immediately,
      * yet no data was placed into the buffer (and thus we did not skip
      * polling). but since EOF is not obtainable until we retrieve an
      * overlapped result, it must be the case that there was data placed
      * into the buffer, or an error was generated by Readfile(). in either
      * case, we should've skipped the polling for this round.
      */
     g_assert(rs->ov_pending);

     success = GetOverlappedResult(c->handle, &rs->ov, &count_read, FALSE);
     if (success) {
         g_debug("thread: overlapped result, count_read: %d", (int)count_read);
         rs->pending += count_read;
         new_events |= G_IO_IN;
     } else {
         error = GetLastError();
         if (error == 0 || error == ERROR_HANDLE_EOF ||
             error == ERROR_NO_SYSTEM_RESOURCES ||
             error == ERROR_OPERATION_ABORTED) {
             /* note: On WinXP SP3 with rhel6ga virtio-win-1.1.16 vioser drivers,
              * ENSR seems to be synonymous with when we'd normally expect
              * ERROR_HANDLE_EOF. So treat it as such. Microsoft's
              * recommendation for ERROR_NO_SYSTEM_RESOURCES is to
              * retry the read, so this happens to work out anyway. On newer
              * virtio-win driver, this seems to be replaced with EOA, so
              * handle that in the same fashion.
              */
             new_events |= G_IO_HUP;
         } else if (error != ERROR_IO_INCOMPLETE) {
             g_critical("error retrieving overlapped result: %d", (int)error);
             new_events |= G_IO_ERR;
         }
     }

     if (new_events) {
         rs->ov_pending = 0;
     }
     c->pending_events |= new_events;

     return !!c->pending_events;
 }

 /*
  * Called by glib after either prepare or check routines signal readiness
  */
 static gboolean ga_channel_dispatch(GSource *source, GSourceFunc unused,
                                     gpointer user_data)
 {
     GAWatch *watch = (GAWatch *)source;
     GAChannel *c = (GAChannel *)watch->channel;
     GAChannelReadState *rs = &c->rstate;
     gboolean success;

     g_debug("dispatch");
     success = c->cb(watch->pollfd.revents, c->user_data);

     if (c->pending_events & G_IO_ERR) {
         g_critical("channel error, removing source");
         return false;
     }

     /* TODO: replace rs->pending with watch->revents */
     c->pending_events &= ~G_IO_HUP;
     if (!rs->pending) {
         c->pending_events &= ~G_IO_IN;
     } else {
         c->pending_events = 0;
     }
     return success;
 }

 static void ga_channel_finalize(GSource *source)
 {
     g_debug("finalize");
 }

 GSourceFuncs ga_channel_watch_funcs = {
     ga_channel_prepare,
     ga_channel_check,
     ga_channel_dispatch,
     ga_channel_finalize
 };

 static GSource *ga_channel_create_watch(GAChannel *c)
 {
     GSource *source = g_source_new(&ga_channel_watch_funcs, sizeof(GAWatch));
     GAWatch *watch = (GAWatch *)source;

     watch->channel = c;
     watch->pollfd.fd = (gintptr) c->rstate.ov.hEvent;
     g_source_add_poll(source, &watch->pollfd);

     return source;
 }

 GIOStatus ga_channel_read(GAChannel *c, char *buf, size_t size, gsize *count)
 {
     GAChannelReadState *rs = &c->rstate;
     GIOStatus status;
     size_t to_read = 0;

     if (c->pending_events & G_IO_ERR) {
         return G_IO_STATUS_ERROR;
     }

     *count = to_read = MIN(size, rs->pending);
     if (to_read) {
         memcpy(buf, rs->buf + rs->cur, to_read);
         rs->cur += to_read;
         rs->pending -= to_read;
         status = G_IO_STATUS_NORMAL;
     } else {
         status = G_IO_STATUS_AGAIN;
     }

     return status;
 }

 static GIOStatus ga_channel_write(GAChannel *c, const char *buf, size_t size,
                                   size_t *count)
 {
     GIOStatus status;
     OVERLAPPED ov = {0};
     BOOL ret;
     DWORD written;

     ov.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
     ret = WriteFile(c->handle, buf, size, &written, &ov);
     if (!ret) {
         if (GetLastError() == ERROR_IO_PENDING) {
             /* write is pending */
             ret = GetOverlappedResult(c->handle, &ov, &written, TRUE);
             if (!ret) {
                 if (!GetLastError()) {
                     status = G_IO_STATUS_AGAIN;
                 } else {
                     status = G_IO_STATUS_ERROR;
                 }
             } else {
                 /* write is complete */
                 status = G_IO_STATUS_NORMAL;
                 *count = written;
             }
         } else {
             status = G_IO_STATUS_ERROR;
         }
     } else {
         /* write returned immediately */
         status = G_IO_STATUS_NORMAL;
         *count = written;
     }

     if (ov.hEvent) {
         CloseHandle(ov.hEvent);
         ov.hEvent = NULL;
     }
     return status;
 }

 GIOStatus ga_channel_write_all(GAChannel *c, const char *buf, size_t size)
 {
     GIOStatus status = G_IO_STATUS_NORMAL;
     size_t count = 0;

     while (size) {
         status = ga_channel_write(c, buf, size, &count);
         if (status == G_IO_STATUS_NORMAL) {
             size -= count;
             buf += count;
         } else if (status != G_IO_STATUS_AGAIN) {
             break;
         }
     }

     return status;
 }

 static gboolean ga_channel_open(GAChannel *c, GAChannelMethod method,
                                 const gchar *path)
 {
     COMMTIMEOUTS comTimeOut = {0};
     gchar newpath[MAXPATHLEN] = {0};
     comTimeOut.ReadIntervalTimeout = 1;

     if (method != GA_CHANNEL_VIRTIO_SERIAL && method != GA_CHANNEL_ISA_SERIAL) {
         g_critical("unsupported communication method");
         return false;
     }

     if (method == GA_CHANNEL_ISA_SERIAL) {
         snprintf(newpath, sizeof(newpath), "\\\\.\\%s", path);
     } else {
         g_strlcpy(newpath, path, sizeof(newpath));
     }

     c->handle = CreateFile(newpath, GENERIC_READ | GENERIC_WRITE, 0, NULL,
                            OPEN_EXISTING,
                            FILE_FLAG_NO_BUFFERING | FILE_FLAG_OVERLAPPED, NULL);
     if (c->handle == INVALID_HANDLE_VALUE) {
         g_autofree gchar *emsg = g_win32_error_message(GetLastError());
         g_critical("error opening path %s: %s", newpath, emsg);
         return false;
     }

     if (method == GA_CHANNEL_ISA_SERIAL
             && !SetCommTimeouts(c->handle, &comTimeOut)) {
         g_autofree gchar *emsg = g_win32_error_message(GetLastError());
         g_critical("error setting timeout for com port: %s", emsg);
         CloseHandle(c->handle);
         return false;
     }

     return true;
 }

 GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path,
                           int listen_fd, GAChannelCallback cb, gpointer opaque)
 {
     GAChannel *c = g_new0(GAChannel, 1);
     SECURITY_ATTRIBUTES sec_attrs;

     if (!ga_channel_open(c, method, path)) {
         g_critical("error opening channel");
         g_free(c);
         return NULL;
     }

     c->cb = cb;
     c->user_data = opaque;

     sec_attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
     sec_attrs.lpSecurityDescriptor = NULL;
     sec_attrs.bInheritHandle = false;

     c->rstate.buf_size = QGA_READ_COUNT_DEFAULT;
     c->rstate.buf = g_malloc(QGA_READ_COUNT_DEFAULT);
     c->rstate.ov.hEvent = CreateEvent(&sec_attrs, FALSE, FALSE, NULL);

     c->source = ga_channel_create_watch(c);
     g_source_attach(c->source, NULL);
     return c;
 }

 void ga_channel_free(GAChannel *c)
 {
     if (c->source) {
         g_source_destroy(c->source);
     }
     if (c->rstate.ov.hEvent) {
         CloseHandle(c->rstate.ov.hEvent);
     }
     g_free(c->rstate.buf);
     g_free(c);
 }
	#include "qemu/osdep.h"
	#include <windows.h>
	#include <io.h>
	#include "guest-agent-core.h"
	#include "channel.h"

	typedef struct GAChannelReadState {
	guint thread_id;
	uint8_t *buf;
	size_t buf_size;
	size_t cur; /* current buffer start */
	size_t pending; /* pending buffered bytes to read */
	OVERLAPPED ov;
	bool ov_pending; /* whether on async read is outstanding */
	} GAChannelReadState;

	struct GAChannel {
	HANDLE handle;
	GAChannelCallback cb;
	gpointer user_data;
	GAChannelReadState rstate;
	GIOCondition pending_events; /* TODO: use GAWatch.pollfd.revents */
	GSource *source;
	};

	typedef struct GAWatch {
	GSource source;
	GPollFD pollfd;
	GAChannel *channel;
	GIOCondition events_mask;
	} GAWatch;

	/*
	* Called by glib prior to polling to set up poll events if polling is needed.
	*
	*/
	static gboolean ga_channel_prepare(GSource source, gint timeout_ms)
	{
	GAWatch watch = (GAWatch )source;
	GAChannel c = (GAChannel )watch->channel;
	GAChannelReadState *rs = &c->rstate;
	DWORD count_read, count_to_read = 0;
	bool success;
	GIOCondition new_events = 0;

	g_debug("prepare");
	/* go ahead and submit another read if there's room in the buffer
	* and no previous reads are outstanding
	*/
	if (!rs->ov_pending) {
	if (rs->cur + rs->pending >= rs->buf_size) {
	if (rs->cur) {
	memmove(rs->buf, rs->buf + rs->cur, rs->pending);
	rs->cur = 0;
	}
	}
	count_to_read = rs->buf_size - rs->cur - rs->pending;
	}

	if (rs->ov_pending \|\| count_to_read <= 0) {
	goto out;
	}

	/* submit the read */
	success = ReadFile(c->handle, rs->buf + rs->cur + rs->pending,
	count_to_read, &count_read, &rs->ov);
	if (success) {
	rs->pending += count_read;
	rs->ov_pending = false;
	} else {
	if (GetLastError() == ERROR_IO_PENDING) {
	rs->ov_pending = true;
	} else {
	new_events \|= G_IO_ERR;
	}
	}

	out:
	/* don't block forever, iterate the main loop every once in a while */
	*timeout_ms = 500;
	/* if there's data in the read buffer, or another event is pending,
	* skip polling and issue user cb.
	*/
	if (rs->pending) {
	new_events \|= G_IO_IN;
	}
	c->pending_events \|= new_events;
	return !!c->pending_events;
	}

	/*
	* Called by glib after an outstanding read request is completed.
	*/
	static gboolean ga_channel_check(GSource *source)
	{
	GAWatch watch = (GAWatch )source;
	GAChannel c = (GAChannel )watch->channel;
	GAChannelReadState *rs = &c->rstate;
	DWORD count_read, error;
	BOOL success;

	GIOCondition new_events = 0;

	g_debug("check");

	/* failing this implies we issued a read that completed immediately,
	* yet no data was placed into the buffer (and thus we did not skip
	* polling). but since EOF is not obtainable until we retrieve an
	* overlapped result, it must be the case that there was data placed
	* into the buffer, or an error was generated by Readfile(). in either
	* case, we should've skipped the polling for this round.
	*/
	g_assert(rs->ov_pending);

	success = GetOverlappedResult(c->handle, &rs->ov, &count_read, FALSE);
	if (success) {
	g_debug("thread: overlapped result, count_read: %d", (int)count_read);
	rs->pending += count_read;
	new_events \|= G_IO_IN;
	} else {
	error = GetLastError();
	if (error == 0 \|\| error == ERROR_HANDLE_EOF \|\|
	error == ERROR_NO_SYSTEM_RESOURCES \|\|
	error == ERROR_OPERATION_ABORTED) {
	/* note: On WinXP SP3 with rhel6ga virtio-win-1.1.16 vioser drivers,
	* ENSR seems to be synonymous with when we'd normally expect
	* ERROR_HANDLE_EOF. So treat it as such. Microsoft's
	* recommendation for ERROR_NO_SYSTEM_RESOURCES is to
	* retry the read, so this happens to work out anyway. On newer
	* virtio-win driver, this seems to be replaced with EOA, so
	* handle that in the same fashion.
	*/
	new_events \|= G_IO_HUP;
	} else if (error != ERROR_IO_INCOMPLETE) {
	g_critical("error retrieving overlapped result: %d", (int)error);
	new_events \|= G_IO_ERR;
	}
	}

	if (new_events) {
	rs->ov_pending = 0;
	}
	c->pending_events \|= new_events;

	return !!c->pending_events;
	}

	/*
	* Called by glib after either prepare or check routines signal readiness
	*/
	static gboolean ga_channel_dispatch(GSource *source, GSourceFunc unused,
	gpointer user_data)
	{
	GAWatch watch = (GAWatch )source;
	GAChannel c = (GAChannel )watch->channel;
	GAChannelReadState *rs = &c->rstate;
	gboolean success;

	g_debug("dispatch");
	success = c->cb(watch->pollfd.revents, c->user_data);

	if (c->pending_events & G_IO_ERR) {
	g_critical("channel error, removing source");
	return false;
	}

	/* TODO: replace rs->pending with watch->revents */
	c->pending_events &= ~G_IO_HUP;
	if (!rs->pending) {
	c->pending_events &= ~G_IO_IN;
	} else {
	c->pending_events = 0;
	}
	return success;
	}

	static void ga_channel_finalize(GSource *source)
	{
	g_debug("finalize");
	}

	GSourceFuncs ga_channel_watch_funcs = {
	ga_channel_prepare,
	ga_channel_check,
	ga_channel_dispatch,
	ga_channel_finalize
	};

	static GSource ga_channel_create_watch(GAChannel c)
	{
	GSource *source = g_source_new(&ga_channel_watch_funcs, sizeof(GAWatch));
	GAWatch watch = (GAWatch )source;

	watch->channel = c;
	watch->pollfd.fd = (gintptr) c->rstate.ov.hEvent;
	g_source_add_poll(source, &watch->pollfd);

	return source;
	}

	GIOStatus ga_channel_read(GAChannel c, char buf, size_t size, gsize *count)
	{
	GAChannelReadState *rs = &c->rstate;
	GIOStatus status;
	size_t to_read = 0;

	if (c->pending_events & G_IO_ERR) {
	return G_IO_STATUS_ERROR;
	}

	*count = to_read = MIN(size, rs->pending);
	if (to_read) {
	memcpy(buf, rs->buf + rs->cur, to_read);
	rs->cur += to_read;
	rs->pending -= to_read;
	status = G_IO_STATUS_NORMAL;
	} else {
	status = G_IO_STATUS_AGAIN;
	}

	return status;
	}

	static GIOStatus ga_channel_write(GAChannel c, const char buf, size_t size,
	size_t *count)
	{
	GIOStatus status;
	OVERLAPPED ov = {0};
	BOOL ret;
	DWORD written;

	ov.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
	ret = WriteFile(c->handle, buf, size, &written, &ov);
	if (!ret) {
	if (GetLastError() == ERROR_IO_PENDING) {
	/* write is pending */
	ret = GetOverlappedResult(c->handle, &ov, &written, TRUE);
	if (!ret) {
	if (!GetLastError()) {
	status = G_IO_STATUS_AGAIN;
	} else {
	status = G_IO_STATUS_ERROR;
	}
	} else {
	/* write is complete */
	status = G_IO_STATUS_NORMAL;
	*count = written;
	}
	} else {
	status = G_IO_STATUS_ERROR;
	}
	} else {
	/* write returned immediately */
	status = G_IO_STATUS_NORMAL;
	*count = written;
	}

	if (ov.hEvent) {
	CloseHandle(ov.hEvent);
	ov.hEvent = NULL;
	}
	return status;
	}

	GIOStatus ga_channel_write_all(GAChannel c, const char buf, size_t size)
	{
	GIOStatus status = G_IO_STATUS_NORMAL;
	size_t count = 0;

	while (size) {
	status = ga_channel_write(c, buf, size, &count);
	if (status == G_IO_STATUS_NORMAL) {
	size -= count;
	buf += count;
	} else if (status != G_IO_STATUS_AGAIN) {
	break;
	}
	}

	return status;
	}

	static gboolean ga_channel_open(GAChannel *c, GAChannelMethod method,
	const gchar *path)
	{
	COMMTIMEOUTS comTimeOut = {0};
	gchar newpath[MAXPATHLEN] = {0};
	comTimeOut.ReadIntervalTimeout = 1;

	if (method != GA_CHANNEL_VIRTIO_SERIAL && method != GA_CHANNEL_ISA_SERIAL) {
	g_critical("unsupported communication method");
	return false;
	}

	if (method == GA_CHANNEL_ISA_SERIAL) {
	snprintf(newpath, sizeof(newpath), "\\\\.\\%s", path);
	} else {
	g_strlcpy(newpath, path, sizeof(newpath));
	}

	c->handle = CreateFile(newpath, GENERIC_READ \| GENERIC_WRITE, 0, NULL,
	OPEN_EXISTING,
	FILE_FLAG_NO_BUFFERING \| FILE_FLAG_OVERLAPPED, NULL);
	if (c->handle == INVALID_HANDLE_VALUE) {
	g_autofree gchar *emsg = g_win32_error_message(GetLastError());
	g_critical("error opening path %s: %s", newpath, emsg);
	return false;
	}

	if (method == GA_CHANNEL_ISA_SERIAL
	&& !SetCommTimeouts(c->handle, &comTimeOut)) {
	g_autofree gchar *emsg = g_win32_error_message(GetLastError());
	g_critical("error setting timeout for com port: %s", emsg);
	CloseHandle(c->handle);
	return false;
	}

	return true;
	}

	GAChannel ga_channel_new(GAChannelMethod method, const gchar path,
	int listen_fd, GAChannelCallback cb, gpointer opaque)
	{
	GAChannel *c = g_new0(GAChannel, 1);
	SECURITY_ATTRIBUTES sec_attrs;

	if (!ga_channel_open(c, method, path)) {
	g_critical("error opening channel");
	g_free(c);
	return NULL;
	}

	c->cb = cb;
	c->user_data = opaque;

	sec_attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
	sec_attrs.lpSecurityDescriptor = NULL;
	sec_attrs.bInheritHandle = false;

	c->rstate.buf_size = QGA_READ_COUNT_DEFAULT;
	c->rstate.buf = g_malloc(QGA_READ_COUNT_DEFAULT);
	c->rstate.ov.hEvent = CreateEvent(&sec_attrs, FALSE, FALSE, NULL);

	c->source = ga_channel_create_watch(c);
	g_source_attach(c->source, NULL);
	return c;
	}

	void ga_channel_free(GAChannel *c)
	{
	if (c->source) {
	g_source_destroy(c->source);
	}
	if (c->rstate.ov.hEvent) {
	CloseHandle(c->rstate.ov.hEvent);
	}
	g_free(c->rstate.buf);
	g_free(c);
	}