qga/channel-win32.c

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