qga/channel-win32.c

   1 #include "qemu/osdep.h"
   2 #include <windows.h>
   3 #include <io.h>
   4 #include "guest-agent-core.h"
   5 #include "channel.h"
   6
   7 typedef struct GAChannelReadState {
   8     guint thread_id;
   9     uint8_t *buf;
  10     size_t buf_size;
  11     size_t cur; /* current buffer start */
  12     size_t pending; /* pending buffered bytes to read */
  13     OVERLAPPED ov;
  14     bool ov_pending; /* whether on async read is outstanding */
  15 } GAChannelReadState;
  16
  17 struct GAChannel {
  18     HANDLE handle;
  19     GAChannelCallback cb;
  20     gpointer user_data;
  21     GAChannelReadState rstate;
  22     GIOCondition pending_events; /* TODO: use GAWatch.pollfd.revents */
  23     GSource *source;
  24 };
  25
  26 typedef struct GAWatch {
  27     GSource source;
  28     GPollFD pollfd;
  29     GAChannel *channel;
  30     GIOCondition events_mask;
  31 } GAWatch;
  32
  33 /*
  34  * Called by glib prior to polling to set up poll events if polling is needed.
  35  *
  36  */
  37 static gboolean ga_channel_prepare(GSource *source, gint *timeout_ms)
  38 {
  39     GAWatch *watch = (GAWatch *)source;
  40     GAChannel *c = (GAChannel *)watch->channel;
  41     GAChannelReadState *rs = &c->rstate;
  42     DWORD count_read, count_to_read = 0;
  43     bool success;
  44     GIOCondition new_events = 0;
  45
  46     g_debug("prepare");
  47     /* go ahead and submit another read if there's room in the buffer
  48      * and no previous reads are outstanding
  49      */
  50     if (!rs->ov_pending) {
  51         if (rs->cur + rs->pending >= rs->buf_size) {
  52             if (rs->cur) {
  53                 memmove(rs->buf, rs->buf + rs->cur, rs->pending);
  54                 rs->cur = 0;
  55             }
  56         }
  57         count_to_read = rs->buf_size - rs->cur - rs->pending;
  58     }
  59
  60     if (rs->ov_pending || count_to_read <= 0) {
  61             goto out;
  62     }
  63
  64     /* submit the read */
  65     success = ReadFile(c->handle, rs->buf + rs->cur + rs->pending,
  66                        count_to_read, &count_read, &rs->ov);
  67     if (success) {
  68         rs->pending += count_read;
  69         rs->ov_pending = false;
  70     } else {
  71         if (GetLastError() == ERROR_IO_PENDING) {
  72             rs->ov_pending = true;
  73         } else {
  74             new_events |= G_IO_ERR;
  75         }
  76     }
  77
  78 out:
  79     /* don't block forever, iterate the main loop every once in a while */
  80     *timeout_ms = 500;
  81     /* if there's data in the read buffer, or another event is pending,
  82      * skip polling and issue user cb.
  83      */
  84     if (rs->pending) {
  85         new_events |= G_IO_IN;
  86     }
  87     c->pending_events |= new_events;
  88     return !!c->pending_events;
  89 }
  90
  91 /*
  92  * Called by glib after an outstanding read request is completed.
  93  */
  94 static gboolean ga_channel_check(GSource *source)
  95 {
  96     GAWatch *watch = (GAWatch *)source;
  97     GAChannel *c = (GAChannel *)watch->channel;
  98     GAChannelReadState *rs = &c->rstate;
  99     DWORD count_read, error;
 100     BOOL success;
 101
 102     GIOCondition new_events = 0;
 103
 104     g_debug("check");
 105
 106     /* failing this implies we issued a read that completed immediately,
 107      * yet no data was placed into the buffer (and thus we did not skip
 108      * polling). but since EOF is not obtainable until we retrieve an
 109      * overlapped result, it must be the case that there was data placed
 110      * into the buffer, or an error was generated by Readfile(). in either
 111      * case, we should've skipped the polling for this round.
 112      */
 113     g_assert(rs->ov_pending);
 114
 115     success = GetOverlappedResult(c->handle, &rs->ov, &count_read, FALSE);
 116     if (success) {
 117         g_debug("thread: overlapped result, count_read: %d", (int)count_read);
 118         rs->pending += count_read;
 119         new_events |= G_IO_IN;
 120     } else {
 121         error = GetLastError();
 122         if (error == 0 || error == ERROR_HANDLE_EOF ||
 123             error == ERROR_NO_SYSTEM_RESOURCES ||
 124             error == ERROR_OPERATION_ABORTED) {
 125             /* note: On WinXP SP3 with rhel6ga virtio-win-1.1.16 vioser drivers,
 126              * ENSR seems to be synonymous with when we'd normally expect
 127              * ERROR_HANDLE_EOF. So treat it as such. Microsoft's
 128              * recommendation for ERROR_NO_SYSTEM_RESOURCES is to
 129              * retry the read, so this happens to work out anyway. On newer
 130              * virtio-win driver, this seems to be replaced with EOA, so
 131              * handle that in the same fashion.
 132              */
 133             new_events |= G_IO_HUP;
 134         } else if (error != ERROR_IO_INCOMPLETE) {
 135             g_critical("error retrieving overlapped result: %d", (int)error);
 136             new_events |= G_IO_ERR;
 137         }
 138     }
 139
 140     if (new_events) {
 141         rs->ov_pending = 0;
 142     }
 143     c->pending_events |= new_events;
 144
 145     return !!c->pending_events;
 146 }
 147
 148 /*
 149  * Called by glib after either prepare or check routines signal readiness
 150  */
 151 static gboolean ga_channel_dispatch(GSource *source, GSourceFunc unused,
 152                                     gpointer user_data)
 153 {
 154     GAWatch *watch = (GAWatch *)source;
 155     GAChannel *c = (GAChannel *)watch->channel;
 156     GAChannelReadState *rs = &c->rstate;
 157     gboolean success;
 158
 159     g_debug("dispatch");
 160     success = c->cb(watch->pollfd.revents, c->user_data);
 161
 162     if (c->pending_events & G_IO_ERR) {
 163         g_critical("channel error, removing source");
 164         return false;
 165     }
 166
 167     /* TODO: replace rs->pending with watch->revents */
 168     c->pending_events &= ~G_IO_HUP;
 169     if (!rs->pending) {
 170         c->pending_events &= ~G_IO_IN;
 171     } else {
 172         c->pending_events = 0;
 173     }
 174     return success;
 175 }
 176
 177 static void ga_channel_finalize(GSource *source)
 178 {
 179     g_debug("finalize");
 180 }
 181
 182 GSourceFuncs ga_channel_watch_funcs = {
 183     ga_channel_prepare,
 184     ga_channel_check,
 185     ga_channel_dispatch,
 186     ga_channel_finalize
 187 };
 188
 189 static GSource *ga_channel_create_watch(GAChannel *c)
 190 {
 191     GSource *source = g_source_new(&ga_channel_watch_funcs, sizeof(GAWatch));
 192     GAWatch *watch = (GAWatch *)source;
 193
 194     watch->channel = c;
 195     watch->pollfd.fd = (gintptr) c->rstate.ov.hEvent;
 196     g_source_add_poll(source, &watch->pollfd);
 197
 198     return source;
 199 }
 200
 201 GIOStatus ga_channel_read(GAChannel *c, char *buf, size_t size, gsize *count)
 202 {
 203     GAChannelReadState *rs = &c->rstate;
 204     GIOStatus status;
 205     size_t to_read = 0;
 206
 207     if (c->pending_events & G_IO_ERR) {
 208         return G_IO_STATUS_ERROR;
 209     }
 210
 211     *count = to_read = MIN(size, rs->pending);
 212     if (to_read) {
 213         memcpy(buf, rs->buf + rs->cur, to_read);
 214         rs->cur += to_read;
 215         rs->pending -= to_read;
 216         status = G_IO_STATUS_NORMAL;
 217     } else {
 218         status = G_IO_STATUS_AGAIN;
 219     }
 220
 221     return status;
 222 }
 223
 224 static GIOStatus ga_channel_write(GAChannel *c, const char *buf, size_t size,
 225                                   size_t *count)
 226 {
 227     GIOStatus status;
 228     OVERLAPPED ov = {0};
 229     BOOL ret;
 230     DWORD written;
 231
 232     ov.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
 233     ret = WriteFile(c->handle, buf, size, &written, &ov);
 234     if (!ret) {
 235         if (GetLastError() == ERROR_IO_PENDING) {
 236             /* write is pending */
 237             ret = GetOverlappedResult(c->handle, &ov, &written, TRUE);
 238             if (!ret) {
 239                 if (!GetLastError()) {
 240                     status = G_IO_STATUS_AGAIN;
 241                 } else {
 242                     status = G_IO_STATUS_ERROR;
 243                 }
 244             } else {
 245                 /* write is complete */
 246                 status = G_IO_STATUS_NORMAL;
 247                 *count = written;
 248             }
 249         } else {
 250             status = G_IO_STATUS_ERROR;
 251         }
 252     } else {
 253         /* write returned immediately */
 254         status = G_IO_STATUS_NORMAL;
 255         *count = written;
 256     }
 257
 258     if (ov.hEvent) {
 259         CloseHandle(ov.hEvent);
 260         ov.hEvent = NULL;
 261     }
 262     return status;
 263 }
 264
 265 GIOStatus ga_channel_write_all(GAChannel *c, const char *buf, size_t size)
 266 {
 267     GIOStatus status = G_IO_STATUS_NORMAL;
 268     size_t count = 0;
 269
 270     while (size) {
 271         status = ga_channel_write(c, buf, size, &count);
 272         if (status == G_IO_STATUS_NORMAL) {
 273             size -= count;
 274             buf += count;
 275         } else if (status != G_IO_STATUS_AGAIN) {
 276             break;
 277         }
 278     }
 279
 280     return status;
 281 }
 282
 283 static gboolean ga_channel_open(GAChannel *c, GAChannelMethod method,
 284                                 const gchar *path)
 285 {
 286     COMMTIMEOUTS comTimeOut = {0};
 287     gchar newpath[MAXPATHLEN] = {0};
 288     comTimeOut.ReadIntervalTimeout = 1;
 289
 290     if (method != GA_CHANNEL_VIRTIO_SERIAL && method != GA_CHANNEL_ISA_SERIAL) {
 291         g_critical("unsupported communication method");
 292         return false;
 293     }
 294
 295     if (method == GA_CHANNEL_ISA_SERIAL) {
 296         snprintf(newpath, sizeof(newpath), "\\\\.\\%s", path);
 297     } else {
 298         g_strlcpy(newpath, path, sizeof(newpath));
 299     }
 300
 301     c->handle = CreateFile(newpath, GENERIC_READ | GENERIC_WRITE, 0, NULL,
 302                            OPEN_EXISTING,
 303                            FILE_FLAG_NO_BUFFERING | FILE_FLAG_OVERLAPPED, NULL);
 304     if (c->handle == INVALID_HANDLE_VALUE) {
 305         g_autofree gchar *emsg = g_win32_error_message(GetLastError());
 306         g_critical("error opening path %s: %s", newpath, emsg);
 307         return false;
 308     }
 309
 310     if (method == GA_CHANNEL_ISA_SERIAL
 311             && !SetCommTimeouts(c->handle, &comTimeOut)) {
 312         g_autofree gchar *emsg = g_win32_error_message(GetLastError());
 313         g_critical("error setting timeout for com port: %s", emsg);
 314         CloseHandle(c->handle);
 315         return false;
 316     }
 317
 318     return true;
 319 }
 320
 321 GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path,
 322                           int listen_fd, GAChannelCallback cb, gpointer opaque)
 323 {
 324     GAChannel *c = g_new0(GAChannel, 1);
 325     SECURITY_ATTRIBUTES sec_attrs;
 326
 327     if (!ga_channel_open(c, method, path)) {
 328         g_critical("error opening channel");
 329         g_free(c);
 330         return NULL;
 331     }
 332
 333     c->cb = cb;
 334     c->user_data = opaque;
 335
 336     sec_attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
 337     sec_attrs.lpSecurityDescriptor = NULL;
 338     sec_attrs.bInheritHandle = false;
 339
 340     c->rstate.buf_size = QGA_READ_COUNT_DEFAULT;
 341     c->rstate.buf = g_malloc(QGA_READ_COUNT_DEFAULT);
 342     c->rstate.ov.hEvent = CreateEvent(&sec_attrs, FALSE, FALSE, NULL);
 343
 344     c->source = ga_channel_create_watch(c);
 345     g_source_attach(c->source, NULL);
 346     return c;
 347 }
 348
 349 void ga_channel_free(GAChannel *c)
 350 {
 351     if (c->source) {
 352         g_source_destroy(c->source);
 353     }
 354     if (c->rstate.ov.hEvent) {
 355         CloseHandle(c->rstate.ov.hEvent);
 356     }
 357     g_free(c->rstate.buf);
 358     g_free(c);
 359 }