lib/stream-windows.c

   1 /*
   2  * Copyright (c) 2016 Cloudbase Solutions Srl
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include <errno.h>
  19 #include <sys/types.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include "poll-loop.h"
  24 #include "dirs.h"
  25 #include "util.h"
  26 #include "stream-provider.h"
  27 #include "openvswitch/vlog.h"
  28
  29 VLOG_DEFINE_THIS_MODULE(stream_windows);
  30
  31 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
  32
  33 static void maybe_unlink_and_free(char *path);
  34
  35 /* Suggested buffer size at the creation of the named pipe for reading and
  36  * and writing operations. */
  37 #define BUFSIZE 65000
  38
  39 /* Default prefix of a local named pipe. */
  40 #define LOCAL_PREFIX "\\\\.\\pipe\\"
  41
  42 /* This function has the purpose to remove all the slashes received in s. */
  43 static char *
  44 remove_slashes(char *s)
  45 {
  46     char *p1, *p2;
  47     p1 = p2 = s;
  48
  49     while (*p1) {
  50         if ((*p1) == '\\' || (*p1) == '/') {
  51             p1++;
  52         } else {
  53             *p2 = *p1;
  54             p2++;
  55             p1++;
  56         }
  57     }
  58     *p2 = '\0';
  59     return s;
  60 }
  61
  62 /* Active named pipe. */
  63 struct windows_stream
  64 {
  65     struct stream stream;
  66     HANDLE fd;
  67     /* Overlapped operations used for reading/writing. */
  68     OVERLAPPED read;
  69     OVERLAPPED write;
  70     /* Flag to check if a reading/writing operation is pending. */
  71     bool read_pending;
  72     bool write_pending;
  73     /* Flag to check if fd is a server HANDLE.  In the case of a server handle
  74      * we have to issue a disconnect before closing the actual handle. */
  75     bool server;
  76     bool retry_connect;
  77     char *pipe_path;
  78 };
  79
  80 static struct windows_stream *
  81 stream_windows_cast(struct stream *stream)
  82 {
  83     stream_assert_class(stream, &windows_stream_class);
  84     return CONTAINER_OF(stream, struct windows_stream, stream);
  85 }
  86
  87 static HANDLE
  88 create_snpipe(char *path)
  89 {
  90     return CreateFile(path, GENERIC_READ | GENERIC_WRITE, 0, NULL,
  91                       OPEN_EXISTING,
  92                       FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED |
  93                       FILE_FLAG_NO_BUFFERING,
  94                       NULL);
  95 }
  96
  97 /* Active named pipe open. */
  98 static int
  99 windows_open(const char *name, char *suffix, struct stream **streamp,
 100              uint8_t dscp OVS_UNUSED)
 101 {
 102     char *connect_path;
 103     HANDLE npipe;
 104     DWORD mode = PIPE_READMODE_BYTE;
 105     char *path;
 106     FILE *file;
 107     bool retry = false;
 108     /* If the path does not contain a ':', assume it is relative to
 109      * OVS_RUNDIR. */
 110     if (!strchr(suffix, ':')) {
 111         path = xasprintf("%s/%s", ovs_rundir(), suffix);
 112     } else {
 113         path = xstrdup(suffix);
 114     }
 115
 116     /* In case of "unix:" argument, the assumption is that there is a file
 117      * created in the path (name). */
 118     file = fopen(path, "r");
 119     if (!file) {
 120         free(path);
 121         VLOG_DBG_RL(&rl, "%s: could not open %s (%s)", name, suffix,
 122                     ovs_strerror(errno));
 123         return ENOENT;
 124     } else {
 125         fclose(file);
 126     }
 127
 128     /* Valid pipe names do not have slashes.  The assumption is that the named
 129      * pipe was created with the name "path", with slashes removed and the
 130      * default prefix \\.\pipe\ appended.
 131      * Strip the slashes from the parameter name and append the default prefix.
 132      */
 133     connect_path = xasprintf("%s%s", LOCAL_PREFIX, remove_slashes(path));
 134     free(path);
 135
 136     /* Try to connect to the named pipe.  In case all pipe instances are
 137      * busy we set the retry flag to true and retry again during the
 138      * connect function.  Use overlapped flag and file no buffering to ensure
 139      * asynchronous operations. */
 140     npipe = create_snpipe(connect_path);
 141
 142     if (npipe == INVALID_HANDLE_VALUE && GetLastError() == ERROR_PIPE_BUSY) {
 143         retry = true;
 144     }
 145
 146     if (!retry && npipe == INVALID_HANDLE_VALUE) {
 147         VLOG_ERR_RL(&rl, "Could not connect to named pipe: %s",
 148                     ovs_lasterror_to_string());
 149         free(connect_path);
 150         return ENOENT;
 151     }
 152     if (!retry && !SetNamedPipeHandleState(npipe, &mode, NULL, NULL)) {
 153         VLOG_ERR_RL(&rl, "Could not set named pipe options: %s",
 154                     ovs_lasterror_to_string());
 155         free(connect_path);
 156         CloseHandle(npipe);
 157         return ENOENT;
 158     }
 159     struct windows_stream *s = xmalloc(sizeof *s);
 160     stream_init(&s->stream, &windows_stream_class, 0, name);
 161     s->pipe_path = connect_path;
 162     s->fd = npipe;
 163     /* This is an active stream. */
 164     s->server = false;
 165     /* Create events for reading and writing to be signaled later. */
 166     memset(&s->read, 0, sizeof(s->read));
 167     memset(&s->write, 0, sizeof(s->write));
 168     s->read.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 169     s->write.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 170     /* Initial read and write operations are not pending. */
 171     s->read_pending = false;
 172     s->write_pending = false;
 173     s->retry_connect = retry;
 174     *streamp = &s->stream;
 175     return 0;
 176 }
 177
 178 /* Active named pipe close. */
 179 static void
 180 windows_close(struct stream *stream)
 181 {
 182     struct windows_stream *s = stream_windows_cast(stream);
 183     /* Disconnect the named pipe in case it was created from a passive stream.
 184      */
 185     if (s->server) {
 186         DisconnectNamedPipe(s->fd);
 187     }
 188     CloseHandle(s->fd);
 189     CloseHandle(s->read.hEvent);
 190     CloseHandle(s->write.hEvent);
 191     if (s->pipe_path) {
 192         free(s->pipe_path);
 193     }
 194     free(s);
 195 }
 196
 197 /* Active named pipe connect. */
 198 static int
 199 windows_connect(struct stream *stream)
 200 {
 201     struct windows_stream *s = stream_windows_cast(stream);
 202
 203     if (!s->retry_connect) {
 204         return 0;
 205     } else {
 206         HANDLE npipe;
 207         npipe = create_snpipe(s->pipe_path);
 208         if (npipe == INVALID_HANDLE_VALUE) {
 209             if (GetLastError() == ERROR_PIPE_BUSY) {
 210                 return EAGAIN;
 211             } else {
 212                 s->retry_connect = false;
 213                 return ENOENT;
 214             }
 215         }
 216         s->retry_connect = false;
 217         s->fd = npipe;
 218         return 0;
 219     }
 220 }
 221
 222 /* Active named pipe receive. */
 223 static ssize_t
 224 windows_recv(struct stream *stream, void *buffer, size_t n)
 225 {
 226     struct windows_stream *s = stream_windows_cast(stream);
 227     ssize_t retval = 0;
 228     boolean result = false;
 229     DWORD last_error = 0;
 230     LPOVERLAPPED  ov = NULL;
 231     ov = &s->read;
 232
 233     /* If the read operation was pending, we verify its result. */
 234     if (s->read_pending) {
 235         if (!GetOverlappedResult(s->fd, ov, &(DWORD)retval, FALSE)) {
 236             last_error = GetLastError();
 237             if (last_error == ERROR_IO_INCOMPLETE) {
 238                 /* If the operation is still pending, retry again. */
 239                 s->read_pending = true;
 240                 return -EAGAIN;
 241             } else if (last_error == ERROR_PIPE_NOT_CONNECTED
 242                        || last_error == ERROR_BAD_PIPE
 243                        || last_error == ERROR_NO_DATA
 244                        || last_error == ERROR_BROKEN_PIPE) {
 245                 /* If the pipe was disconnected, return 0. */
 246                 return 0;
 247             } else {
 248                 VLOG_ERR_RL(&rl, "Could not receive data on named pipe. Last "
 249                             "error: %s", ovs_lasterror_to_string());
 250                 return -EINVAL;
 251             }
 252         }
 253         s->read_pending = false;
 254         return retval;
 255     }
 256
 257     result = ReadFile(s->fd, buffer, n, &(DWORD)retval, ov);
 258
 259     if (!result && GetLastError() == ERROR_IO_PENDING) {
 260         /* Mark the read operation as pending. */
 261         s->read_pending = true;
 262         return -EAGAIN;
 263     } else if (!result) {
 264         last_error = GetLastError();
 265         if (last_error == ERROR_PIPE_NOT_CONNECTED
 266             || last_error == ERROR_BAD_PIPE
 267             || last_error == ERROR_NO_DATA
 268             || last_error == ERROR_BROKEN_PIPE) {
 269             /* If the pipe was disconnected, return 0. */
 270             return 0;
 271         }
 272         VLOG_ERR_RL(&rl, "Could not receive data synchronous on named pipe."
 273                     "Last error: %s", ovs_lasterror_to_string());
 274         return -EINVAL;
 275     }
 276
 277     return retval;
 278 }
 279
 280 /* Active named pipe send. */
 281 static ssize_t
 282 windows_send(struct stream *stream, const void *buffer, size_t n)
 283 {
 284     struct windows_stream *s = stream_windows_cast(stream);
 285     ssize_t retval = 0;
 286     boolean result = false;
 287     DWORD last_error = 0;
 288     LPOVERLAPPED  ov = NULL;
 289     ov = &s->write;
 290
 291     /* If the send operation was pending, we verify the result. */
 292     if (s->write_pending) {
 293         if (!GetOverlappedResult(s->fd, ov, &(DWORD)retval, FALSE)) {
 294             last_error = GetLastError();
 295             if (last_error == ERROR_IO_INCOMPLETE) {
 296                 /* If the operation is still pending, retry again. */
 297                 s->write_pending = true;
 298                 return -EAGAIN;
 299             } else if (last_error == ERROR_PIPE_NOT_CONNECTED
 300                        || last_error == ERROR_BAD_PIPE
 301                        || last_error == ERROR_NO_DATA
 302                        || last_error == ERROR_BROKEN_PIPE) {
 303                 /* If the pipe was disconnected, return connection reset. */
 304                 return -WSAECONNRESET;
 305             } else {
 306                 VLOG_ERR_RL(&rl, "Could not send data on named pipe. Last "
 307                             "error: %s", ovs_lasterror_to_string());
 308                 return -EINVAL;
 309             }
 310         }
 311         s->write_pending = false;
 312         return retval;
 313     }
 314
 315     result = WriteFile(s->fd, buffer, n, &(DWORD)retval, ov);
 316     last_error = GetLastError();
 317     if (!result && GetLastError() == ERROR_IO_PENDING) {
 318         /* Mark the send operation as pending. */
 319         s->write_pending = true;
 320         return -EAGAIN;
 321     } else if (!result && (last_error == ERROR_PIPE_NOT_CONNECTED
 322                            || last_error == ERROR_BAD_PIPE
 323                            || last_error == ERROR_NO_DATA
 324                            || last_error == ERROR_BROKEN_PIPE)) {
 325         /* If the pipe was disconnected, return connection reset. */
 326         return -WSAECONNRESET;
 327     } else if (!result) {
 328         VLOG_ERR_RL(&rl, "Could not send data on synchronous named pipe. Last "
 329                     "error: %s", ovs_lasterror_to_string());
 330         return -EINVAL;
 331     }
 332     return (retval > 0 ? retval : -EAGAIN);
 333 }
 334
 335 /* Active named pipe wait. */
 336 static void
 337 windows_wait(struct stream *stream, enum stream_wait_type wait)
 338 {
 339     struct windows_stream *s = stream_windows_cast(stream);
 340     switch (wait) {
 341     case STREAM_SEND:
 342         poll_wevent_wait(s->write.hEvent);
 343         break;
 344
 345     case STREAM_CONNECT:
 346         poll_immediate_wake();
 347         break;
 348
 349     case STREAM_RECV:
 350         poll_wevent_wait(s->read.hEvent);
 351         break;
 352
 353     default:
 354         OVS_NOT_REACHED();
 355     }
 356 }
 357
 358 /* Passive named pipe. */
 359 const struct stream_class windows_stream_class = {
 360     "unix",                     /* name */
 361     false,                      /* needs_probes */
 362     windows_open,               /* open */
 363     windows_close,              /* close */
 364     windows_connect,            /* connect */
 365     windows_recv,               /* recv */
 366     windows_send,               /* send */
 367     NULL,                       /* run */
 368     NULL,                       /* run_wait */
 369     windows_wait,               /* wait */
 370 };
 371
 372 struct pwindows_pstream
 373 {
 374     struct pstream pstream;
 375     HANDLE fd;
 376     /* Unlink path to be deleted during close. */
 377     char *unlink_path;
 378     /* Overlapped operation used for connect. */
 379     OVERLAPPED connect;
 380     /* Flag to check if an operation is pending. */
 381     bool pending;
 382     /* String used to create the named pipe. */
 383     char *pipe_path;
 384 };
 385
 386 const struct pstream_class pwindows_pstream_class;
 387
 388 static struct pwindows_pstream *
 389 pwindows_pstream_cast(struct pstream *pstream)
 390 {
 391     pstream_assert_class(pstream, &pwindows_pstream_class);
 392     return CONTAINER_OF(pstream, struct pwindows_pstream, pstream);
 393 }
 394
 395 /* Create a named pipe with read/write access, overlapped, message mode for
 396  * writing, byte mode for reading and with a maximum of 64 active instances. */
 397 static HANDLE
 398 create_pnpipe(char *name)
 399 {
 400     SECURITY_ATTRIBUTES sa;
 401     sa.nLength = sizeof(sa);
 402     sa.lpSecurityDescriptor = NULL;
 403     sa.bInheritHandle = TRUE;
 404     if (strlen(name) > 256) {
 405         VLOG_ERR_RL(&rl, "Named pipe name too long.");
 406         return INVALID_HANDLE_VALUE;
 407     }
 408     return CreateNamedPipe(name, PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
 409                            PIPE_TYPE_MESSAGE | PIPE_READMODE_BYTE | PIPE_WAIT,
 410                            64, BUFSIZE, BUFSIZE, 0, &sa);
 411 }
 412
 413 /* Passive named pipe connect.  This function creates a new named pipe and
 414  * passes the old handle to the active stream. */
 415 static int
 416 pwindows_accept(struct pstream *pstream, struct stream **new_streamp)
 417 {
 418     struct pwindows_pstream *p = pwindows_pstream_cast(pstream);
 419     DWORD last_error = 0;
 420     DWORD cbRet;
 421     HANDLE npipe;
 422
 423     /* If the connect operation was pending, verify the result. */
 424     if (p->pending) {
 425         if (!GetOverlappedResult(p->fd, &p->connect, &cbRet, FALSE)) {
 426             last_error = GetLastError();
 427             if (last_error == ERROR_IO_INCOMPLETE) {
 428                 /* If the operation is still pending, retry again. */
 429                 p->pending = true;
 430                 return EAGAIN;
 431             } else {
 432                 VLOG_ERR_RL(&rl, "Could not connect named pipe. Last "
 433                             "error: %s", ovs_lasterror_to_string());
 434                 DisconnectNamedPipe(p->fd);
 435                 return EINVAL;
 436             }
 437         }
 438         p->pending = false;
 439     }
 440
 441     if (!p->pending && !ConnectNamedPipe(p->fd, &p->connect)) {
 442         last_error = GetLastError();
 443         if (last_error == ERROR_IO_PENDING) {
 444             /* Mark the accept operation as pending. */
 445             p->pending = true;
 446             return EAGAIN;
 447         } else if (last_error != ERROR_PIPE_CONNECTED) {
 448             VLOG_ERR_RL(&rl, "Could not connect synchronous named pipe. Last "
 449                         "error: %s", ovs_lasterror_to_string());
 450             DisconnectNamedPipe(p->fd);
 451             return EINVAL;
 452         } else {
 453             /* If the pipe is connected, signal an event. */
 454             SetEvent(&p->connect.hEvent);
 455         }
 456     }
 457
 458     npipe = create_pnpipe(p->pipe_path);
 459     if (npipe == INVALID_HANDLE_VALUE) {
 460         VLOG_ERR_RL(&rl, "Could not create a new named pipe after connect. ",
 461                     ovs_lasterror_to_string());
 462         return ENOENT;
 463     }
 464
 465     /* Give the handle p->fd to the new created active stream and specify it
 466      * was created by an active stream. */
 467     struct windows_stream *p_temp = xmalloc(sizeof *p_temp);
 468     stream_init(&p_temp->stream, &windows_stream_class, 0, "unix");
 469     p_temp->fd = p->fd;
 470     /* Specify it was created by a passive stream. */
 471     p_temp->server = true;
 472     /* Create events for read/write operations. */
 473     memset(&p_temp->read, 0, sizeof(p_temp->read));
 474     memset(&p_temp->write, 0, sizeof(p_temp->write));
 475     p_temp->read.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 476     p_temp->write.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 477     p_temp->read_pending = false;
 478     p_temp->write_pending = false;
 479     p_temp->retry_connect = false;
 480     p_temp->pipe_path = NULL;
 481     *new_streamp = &p_temp->stream;
 482
 483     /* The passive handle p->fd will be the new created handle. */
 484     p->fd = npipe;
 485     memset(&p->connect, 0, sizeof(p->connect));
 486     p->connect.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 487     p->pending = false;
 488     return 0;
 489 }
 490
 491 /* Passive named pipe close. */
 492 static void
 493 pwindows_close(struct pstream *pstream)
 494 {
 495     struct pwindows_pstream *p = pwindows_pstream_cast(pstream);
 496     DisconnectNamedPipe(p->fd);
 497     CloseHandle(p->fd);
 498     CloseHandle(p->connect.hEvent);
 499     maybe_unlink_and_free(p->unlink_path);
 500     free(p->pipe_path);
 501     free(p);
 502 }
 503
 504 /* Passive named pipe wait. */
 505 static void
 506 pwindows_wait(struct pstream *pstream)
 507 {
 508     struct pwindows_pstream *p = pwindows_pstream_cast(pstream);
 509     poll_wevent_wait(p->connect.hEvent);
 510 }
 511
 512 /* Passive named pipe. */
 513 static int
 514 pwindows_open(const char *name OVS_UNUSED, char *suffix,
 515               struct pstream **pstreamp, uint8_t dscp OVS_UNUSED)
 516 {
 517     char *bind_path;
 518     int error;
 519     HANDLE npipe;
 520     char *orig_path;
 521
 522     char *path;
 523     if (!strchr(suffix, ':')) {
 524         path = xasprintf("%s/%s", ovs_rundir(), suffix);
 525     } else {
 526         path = xstrdup(suffix);
 527     }
 528
 529     /* Try to create a file under the path location. */
 530     FILE *file = fopen(path, "w");
 531     if (!file) {
 532         free(path);
 533         error = errno;
 534         VLOG_DBG_RL(&rl, "could not open %s (%s)", path, ovs_strerror(error));
 535         return error;
 536     } else {
 537         fclose(file);
 538     }
 539
 540     orig_path = xstrdup(path);
 541     /* Strip slashes from path and create a named pipe using that newly created
 542      * string. */
 543     bind_path = xasprintf("%s%s", LOCAL_PREFIX, remove_slashes(path));
 544     free(path);
 545
 546     npipe = create_pnpipe(bind_path);
 547
 548     if (npipe == INVALID_HANDLE_VALUE) {
 549         VLOG_ERR_RL(&rl, "Could not create named pipe. Last error: %s",
 550                     ovs_lasterror_to_string());
 551         return ENOENT;
 552     }
 553
 554     struct pwindows_pstream *p = xmalloc(sizeof *p);
 555     pstream_init(&p->pstream, &pwindows_pstream_class, name);
 556     p->fd = npipe;
 557     p->unlink_path = orig_path;
 558     memset(&p->connect, 0, sizeof(p->connect));
 559     p->connect.hEvent = CreateEvent(NULL, TRUE, TRUE, NULL);
 560     p->pending = false;
 561     p->pipe_path = bind_path;
 562     *pstreamp = &p->pstream;
 563     return 0;
 564 }
 565
 566 const struct pstream_class pwindows_pstream_class = {
 567     "punix",
 568     false,                   /* probes */
 569     pwindows_open,           /* open */
 570     pwindows_close,          /* close */
 571     pwindows_accept,         /* accept */
 572     pwindows_wait,           /* wait */
 573 };
 574
 575 /* Helper functions. */
 576 static void
 577 maybe_unlink_and_free(char *path)
 578 {
 579     if (path) {
 580         fatal_signal_unlink_file_now(path);
 581         free(path);
 582     }
 583 }