lib/poll.c

   1 /* Emulation for poll(2)
   2    Contributed by Paolo Bonzini.
   3
   4    Copyright 2001-2003, 2006-2011 Free Software Foundation, Inc.
   5
   6    This file is part of gnulib.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License along
  19    with this program; if not, write to the Free Software Foundation,
  20    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  21
  22 /* Tell gcc not to warn about the (nfd < 0) tests, below.  */
  23 #if (__GNUC__ == 4 && 3 <= __GNUC_MINOR__) || 4 < __GNUC__
  24 # pragma GCC diagnostic ignored "-Wtype-limits"
  25 #endif
  26
  27 #include <config.h>
  28 #include <alloca.h>
  29
  30 #include <sys/types.h>
  31
  32 /* Specification.  */
  33 #include <poll.h>
  34
  35 #include <errno.h>
  36 #include <limits.h>
  37 #include <assert.h>
  38
  39 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  40 # define WIN32_NATIVE
  41 # include <winsock2.h>
  42 # include <windows.h>
  43 # include <io.h>
  44 # include <stdio.h>
  45 # include <conio.h>
  46 #else
  47 # include <sys/time.h>
  48 # include <sys/socket.h>
  49 # include <sys/select.h>
  50 # include <unistd.h>
  51 #endif
  52
  53 #ifdef HAVE_SYS_IOCTL_H
  54 # include <sys/ioctl.h>
  55 #endif
  56 #ifdef HAVE_SYS_FILIO_H
  57 # include <sys/filio.h>
  58 #endif
  59
  60 #include <time.h>
  61
  62 #ifndef INFTIM
  63 # define INFTIM (-1)
  64 #endif
  65
  66 /* BeOS does not have MSG_PEEK.  */
  67 #ifndef MSG_PEEK
  68 # define MSG_PEEK 0
  69 #endif
  70
  71 #ifdef WIN32_NATIVE
  72
  73 #define IsConsoleHandle(h) (((long) (h) & 3) == 3)
  74
  75 static BOOL
  76 IsSocketHandle (HANDLE h)
  77 {
  78   WSANETWORKEVENTS ev;
  79
  80   if (IsConsoleHandle (h))
  81     return FALSE;
  82
  83   /* Under Wine, it seems that getsockopt returns 0 for pipes too.
  84      WSAEnumNetworkEvents instead distinguishes the two correctly.  */
  85   ev.lNetworkEvents = 0xDEADBEEF;
  86   WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev);
  87   return ev.lNetworkEvents != 0xDEADBEEF;
  88 }
  89
  90 /* Declare data structures for ntdll functions.  */
  91 typedef struct _FILE_PIPE_LOCAL_INFORMATION {
  92   ULONG NamedPipeType;
  93   ULONG NamedPipeConfiguration;
  94   ULONG MaximumInstances;
  95   ULONG CurrentInstances;
  96   ULONG InboundQuota;
  97   ULONG ReadDataAvailable;
  98   ULONG OutboundQuota;
  99   ULONG WriteQuotaAvailable;
 100   ULONG NamedPipeState;
 101   ULONG NamedPipeEnd;
 102 } FILE_PIPE_LOCAL_INFORMATION, *PFILE_PIPE_LOCAL_INFORMATION;
 103
 104 typedef struct _IO_STATUS_BLOCK
 105 {
 106   union {
 107     DWORD Status;
 108     PVOID Pointer;
 109   } u;
 110   ULONG_PTR Information;
 111 } IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;
 112
 113 typedef enum _FILE_INFORMATION_CLASS {
 114   FilePipeLocalInformation = 24
 115 } FILE_INFORMATION_CLASS, *PFILE_INFORMATION_CLASS;
 116
 117 typedef DWORD (WINAPI *PNtQueryInformationFile)
 118          (HANDLE, IO_STATUS_BLOCK *, VOID *, ULONG, FILE_INFORMATION_CLASS);
 119
 120 # ifndef PIPE_BUF
 121 #  define PIPE_BUF      512
 122 # endif
 123
 124 /* Compute revents values for file handle H.  If some events cannot happen
 125    for the handle, eliminate them from *P_SOUGHT.  */
 126
 127 static int
 128 win32_compute_revents (HANDLE h, int *p_sought)
 129 {
 130   int i, ret, happened;
 131   INPUT_RECORD *irbuffer;
 132   DWORD avail, nbuffer;
 133   BOOL bRet;
 134   IO_STATUS_BLOCK iosb;
 135   FILE_PIPE_LOCAL_INFORMATION fpli;
 136   static PNtQueryInformationFile NtQueryInformationFile;
 137   static BOOL once_only;
 138
 139   switch (GetFileType (h))
 140     {
 141     case FILE_TYPE_PIPE:
 142       if (!once_only)
 143         {
 144           NtQueryInformationFile = (PNtQueryInformationFile)
 145             GetProcAddress (GetModuleHandle ("ntdll.dll"),
 146                             "NtQueryInformationFile");
 147           once_only = TRUE;
 148         }
 149
 150       happened = 0;
 151       if (PeekNamedPipe (h, NULL, 0, NULL, &avail, NULL) != 0)
 152         {
 153           if (avail)
 154             happened |= *p_sought & (POLLIN | POLLRDNORM);
 155         }
 156       else if (GetLastError () == ERROR_BROKEN_PIPE)
 157         happened |= POLLHUP;
 158
 159       else
 160         {
 161           /* It was the write-end of the pipe.  Check if it is writable.
 162              If NtQueryInformationFile fails, optimistically assume the pipe is
 163              writable.  This could happen on Win9x, where NtQueryInformationFile
 164              is not available, or if we inherit a pipe that doesn't permit
 165              FILE_READ_ATTRIBUTES access on the write end (I think this should
 166              not happen since WinXP SP2; WINE seems fine too).  Otherwise,
 167              ensure that enough space is available for atomic writes.  */
 168           memset (&iosb, 0, sizeof (iosb));
 169           memset (&fpli, 0, sizeof (fpli));
 170
 171           if (!NtQueryInformationFile
 172               || NtQueryInformationFile (h, &iosb, &fpli, sizeof (fpli),
 173                                          FilePipeLocalInformation)
 174               || fpli.WriteQuotaAvailable >= PIPE_BUF
 175               || (fpli.OutboundQuota < PIPE_BUF &&
 176                   fpli.WriteQuotaAvailable == fpli.OutboundQuota))
 177             happened |= *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);
 178         }
 179       return happened;
 180
 181     case FILE_TYPE_CHAR:
 182       ret = WaitForSingleObject (h, 0);
 183       if (!IsConsoleHandle (h))
 184         return ret == WAIT_OBJECT_0 ? *p_sought & ~(POLLPRI | POLLRDBAND) : 0;
 185
 186       nbuffer = avail = 0;
 187       bRet = GetNumberOfConsoleInputEvents (h, &nbuffer);
 188       if (bRet)
 189         {
 190           /* Input buffer.  */
 191           *p_sought &= POLLIN | POLLRDNORM;
 192           if (nbuffer == 0)
 193             return POLLHUP;
 194           if (!*p_sought)
 195             return 0;
 196
 197           irbuffer = (INPUT_RECORD *) alloca (nbuffer * sizeof (INPUT_RECORD));
 198           bRet = PeekConsoleInput (h, irbuffer, nbuffer, &avail);
 199           if (!bRet || avail == 0)
 200             return POLLHUP;
 201
 202           for (i = 0; i < avail; i++)
 203             if (irbuffer[i].EventType == KEY_EVENT)
 204               return *p_sought;
 205           return 0;
 206         }
 207       else
 208         {
 209           /* Screen buffer.  */
 210           *p_sought &= POLLOUT | POLLWRNORM | POLLWRBAND;
 211           return *p_sought;
 212         }
 213
 214     default:
 215       ret = WaitForSingleObject (h, 0);
 216       if (ret == WAIT_OBJECT_0)
 217         return *p_sought & ~(POLLPRI | POLLRDBAND);
 218
 219       return *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);
 220     }
 221 }
 222
 223 /* Convert fd_sets returned by select into revents values.  */
 224
 225 static int
 226 win32_compute_revents_socket (SOCKET h, int sought, long lNetworkEvents)
 227 {
 228   int happened = 0;
 229
 230   if ((lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE)) == FD_ACCEPT)
 231     happened |= (POLLIN | POLLRDNORM) & sought;
 232
 233   else if (lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE))
 234     {
 235       int r, error;
 236
 237       char data[64];
 238       WSASetLastError (0);
 239       r = recv (h, data, sizeof (data), MSG_PEEK);
 240       error = WSAGetLastError ();
 241       WSASetLastError (0);
 242
 243       if (r > 0 || error == WSAENOTCONN)
 244         happened |= (POLLIN | POLLRDNORM) & sought;
 245
 246       /* Distinguish hung-up sockets from other errors.  */
 247       else if (r == 0 || error == WSAESHUTDOWN || error == WSAECONNRESET
 248                || error == WSAECONNABORTED || error == WSAENETRESET)
 249         happened |= POLLHUP;
 250
 251       else
 252         happened |= POLLERR;
 253     }
 254
 255   if (lNetworkEvents & (FD_WRITE | FD_CONNECT))
 256     happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
 257
 258   if (lNetworkEvents & FD_OOB)
 259     happened |= (POLLPRI | POLLRDBAND) & sought;
 260
 261   return happened;
 262 }
 263
 264 #else /* !MinGW */
 265
 266 /* Convert select(2) returned fd_sets into poll(2) revents values.  */
 267 static int
 268 compute_revents (int fd, int sought, fd_set *rfds, fd_set *wfds, fd_set *efds)
 269 {
 270   int happened = 0;
 271   if (FD_ISSET (fd, rfds))
 272     {
 273       int r;
 274       int socket_errno;
 275
 276 # if defined __MACH__ && defined __APPLE__
 277       /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
 278          for some kinds of descriptors.  Detect if this descriptor is a
 279          connected socket, a server socket, or something else using a
 280          0-byte recv, and use ioctl(2) to detect POLLHUP.  */
 281       r = recv (fd, NULL, 0, MSG_PEEK);
 282       socket_errno = (r < 0) ? errno : 0;
 283       if (r == 0 || socket_errno == ENOTSOCK)
 284         ioctl (fd, FIONREAD, &r);
 285 # else
 286       char data[64];
 287       r = recv (fd, data, sizeof (data), MSG_PEEK);
 288       socket_errno = (r < 0) ? errno : 0;
 289 # endif
 290       if (r == 0)
 291         happened |= POLLHUP;
 292
 293       /* If the event happened on an unconnected server socket,
 294          that's fine. */
 295       else if (r > 0 || ( /* (r == -1) && */ socket_errno == ENOTCONN))
 296         happened |= (POLLIN | POLLRDNORM) & sought;
 297
 298       /* Distinguish hung-up sockets from other errors.  */
 299       else if (socket_errno == ESHUTDOWN || socket_errno == ECONNRESET
 300                || socket_errno == ECONNABORTED || socket_errno == ENETRESET)
 301         happened |= POLLHUP;
 302
 303       else
 304         happened |= POLLERR;
 305     }
 306
 307   if (FD_ISSET (fd, wfds))
 308     happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
 309
 310   if (FD_ISSET (fd, efds))
 311     happened |= (POLLPRI | POLLRDBAND) & sought;
 312
 313   return happened;
 314 }
 315 #endif /* !MinGW */
 316
 317 int
 318 poll (struct pollfd *pfd, nfds_t nfd, int timeout)
 319 {
 320 #ifndef WIN32_NATIVE
 321   fd_set rfds, wfds, efds;
 322   struct timeval tv;
 323   struct timeval *ptv;
 324   int maxfd, rc;
 325   nfds_t i;
 326
 327 # ifdef _SC_OPEN_MAX
 328   static int sc_open_max = -1;
 329
 330   if (nfd < 0
 331       || (nfd > sc_open_max
 332           && (sc_open_max != -1
 333               || nfd > (sc_open_max = sysconf (_SC_OPEN_MAX)))))
 334     {
 335       errno = EINVAL;
 336       return -1;
 337     }
 338 # else /* !_SC_OPEN_MAX */
 339 #  ifdef OPEN_MAX
 340   if (nfd < 0 || nfd > OPEN_MAX)
 341     {
 342       errno = EINVAL;
 343       return -1;
 344     }
 345 #  endif /* OPEN_MAX -- else, no check is needed */
 346 # endif /* !_SC_OPEN_MAX */
 347
 348   /* EFAULT is not necessary to implement, but let's do it in the
 349      simplest case. */
 350   if (!pfd)
 351     {
 352       errno = EFAULT;
 353       return -1;
 354     }
 355
 356   /* convert timeout number into a timeval structure */
 357   if (timeout == 0)
 358     {
 359       ptv = &tv;
 360       ptv->tv_sec = 0;
 361       ptv->tv_usec = 0;
 362     }
 363   else if (timeout > 0)
 364     {
 365       ptv = &tv;
 366       ptv->tv_sec = timeout / 1000;
 367       ptv->tv_usec = (timeout % 1000) * 1000;
 368     }
 369   else if (timeout == INFTIM)
 370     /* wait forever */
 371     ptv = NULL;
 372   else
 373     {
 374       errno = EINVAL;
 375       return -1;
 376     }
 377
 378   /* create fd sets and determine max fd */
 379   maxfd = -1;
 380   FD_ZERO (&rfds);
 381   FD_ZERO (&wfds);
 382   FD_ZERO (&efds);
 383   for (i = 0; i < nfd; i++)
 384     {
 385       if (pfd[i].fd < 0)
 386         continue;
 387
 388       if (pfd[i].events & (POLLIN | POLLRDNORM))
 389         FD_SET (pfd[i].fd, &rfds);
 390
 391       /* see select(2): "the only exceptional condition detectable
 392          is out-of-band data received on a socket", hence we push
 393          POLLWRBAND events onto wfds instead of efds. */
 394       if (pfd[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND))
 395         FD_SET (pfd[i].fd, &wfds);
 396       if (pfd[i].events & (POLLPRI | POLLRDBAND))
 397         FD_SET (pfd[i].fd, &efds);
 398       if (pfd[i].fd >= maxfd
 399           && (pfd[i].events & (POLLIN | POLLOUT | POLLPRI
 400                                | POLLRDNORM | POLLRDBAND
 401                                | POLLWRNORM | POLLWRBAND)))
 402         {
 403           maxfd = pfd[i].fd;
 404           if (maxfd > FD_SETSIZE)
 405             {
 406               errno = EOVERFLOW;
 407               return -1;
 408             }
 409         }
 410     }
 411
 412   /* examine fd sets */
 413   rc = select (maxfd + 1, &rfds, &wfds, &efds, ptv);
 414   if (rc < 0)
 415     return rc;
 416
 417   /* establish results */
 418   rc = 0;
 419   for (i = 0; i < nfd; i++)
 420     if (pfd[i].fd < 0)
 421       pfd[i].revents = 0;
 422     else
 423       {
 424         int happened = compute_revents (pfd[i].fd, pfd[i].events,
 425                                         &rfds, &wfds, &efds);
 426         if (happened)
 427           {
 428             pfd[i].revents = happened;
 429             rc++;
 430           }
 431       }
 432
 433   return rc;
 434 #else
 435   static struct timeval tv0;
 436   static HANDLE hEvent;
 437   WSANETWORKEVENTS ev;
 438   HANDLE h, handle_array[FD_SETSIZE + 2];
 439   DWORD ret, wait_timeout, nhandles;
 440   fd_set rfds, wfds, xfds;
 441   BOOL poll_again;
 442   MSG msg;
 443   int rc = 0;
 444   nfds_t i;
 445
 446   if (nfd < 0 || timeout < -1)
 447     {
 448       errno = EINVAL;
 449       return -1;
 450     }
 451
 452   if (!hEvent)
 453     hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
 454
 455   handle_array[0] = hEvent;
 456   nhandles = 1;
 457   FD_ZERO (&rfds);
 458   FD_ZERO (&wfds);
 459   FD_ZERO (&xfds);
 460
 461   /* Classify socket handles and create fd sets. */
 462   for (i = 0; i < nfd; i++)
 463     {
 464       int sought = pfd[i].events;
 465       pfd[i].revents = 0;
 466       if (pfd[i].fd < 0)
 467         continue;
 468       if (!(sought & (POLLIN | POLLRDNORM | POLLOUT | POLLWRNORM | POLLWRBAND
 469                       | POLLPRI | POLLRDBAND)))
 470         continue;
 471
 472       h = (HANDLE) _get_osfhandle (pfd[i].fd);
 473       assert (h != NULL);
 474       if (IsSocketHandle (h))
 475         {
 476           int requested = FD_CLOSE;
 477
 478           /* see above; socket handles are mapped onto select.  */
 479           if (sought & (POLLIN | POLLRDNORM))
 480             {
 481               requested |= FD_READ | FD_ACCEPT;
 482               FD_SET ((SOCKET) h, &rfds);
 483             }
 484           if (sought & (POLLOUT | POLLWRNORM | POLLWRBAND))
 485             {
 486               requested |= FD_WRITE | FD_CONNECT;
 487               FD_SET ((SOCKET) h, &wfds);
 488             }
 489           if (sought & (POLLPRI | POLLRDBAND))
 490             {
 491               requested |= FD_OOB;
 492               FD_SET ((SOCKET) h, &xfds);
 493             }
 494
 495           if (requested)
 496             WSAEventSelect ((SOCKET) h, hEvent, requested);
 497         }
 498       else
 499         {
 500           /* Poll now.  If we get an event, do not poll again.  Also,
 501              screen buffer handles are waitable, and they'll block until
 502              a character is available.  win32_compute_revents eliminates
 503              bits for the "wrong" direction. */
 504           pfd[i].revents = win32_compute_revents (h, &sought);
 505           if (sought)
 506             handle_array[nhandles++] = h;
 507           if (pfd[i].revents)
 508             timeout = 0;
 509         }
 510     }
 511
 512   if (select (0, &rfds, &wfds, &xfds, &tv0) > 0)
 513     {
 514       /* Do MsgWaitForMultipleObjects anyway to dispatch messages, but
 515          no need to call select again.  */
 516       poll_again = FALSE;
 517       wait_timeout = 0;
 518     }
 519   else
 520     {
 521       poll_again = TRUE;
 522       if (timeout == INFTIM)
 523         wait_timeout = INFINITE;
 524       else
 525         wait_timeout = timeout;
 526     }
 527
 528   for (;;)
 529     {
 530       ret = MsgWaitForMultipleObjects (nhandles, handle_array, FALSE,
 531                                        wait_timeout, QS_ALLINPUT);
 532
 533       if (ret == WAIT_OBJECT_0 + nhandles)
 534         {
 535           /* new input of some other kind */
 536           BOOL bRet;
 537           while ((bRet = PeekMessage (&msg, NULL, 0, 0, PM_REMOVE)) != 0)
 538             {
 539               TranslateMessage (&msg);
 540               DispatchMessage (&msg);
 541             }
 542         }
 543       else
 544         break;
 545     }
 546
 547   if (poll_again)
 548     select (0, &rfds, &wfds, &xfds, &tv0);
 549
 550   /* Place a sentinel at the end of the array.  */
 551   handle_array[nhandles] = NULL;
 552   nhandles = 1;
 553   for (i = 0; i < nfd; i++)
 554     {
 555       int happened;
 556
 557       if (pfd[i].fd < 0)
 558         continue;
 559       if (!(pfd[i].events & (POLLIN | POLLRDNORM |
 560                              POLLOUT | POLLWRNORM | POLLWRBAND)))
 561         continue;
 562
 563       h = (HANDLE) _get_osfhandle (pfd[i].fd);
 564       if (h != handle_array[nhandles])
 565         {
 566           /* It's a socket.  */
 567           WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev);
 568           WSAEventSelect ((SOCKET) h, 0, 0);
 569
 570           /* If we're lucky, WSAEnumNetworkEvents already provided a way
 571              to distinguish FD_READ and FD_ACCEPT; this saves a recv later.  */
 572           if (FD_ISSET ((SOCKET) h, &rfds)
 573               && !(ev.lNetworkEvents & (FD_READ | FD_ACCEPT)))
 574             ev.lNetworkEvents |= FD_READ | FD_ACCEPT;
 575           if (FD_ISSET ((SOCKET) h, &wfds))
 576             ev.lNetworkEvents |= FD_WRITE | FD_CONNECT;
 577           if (FD_ISSET ((SOCKET) h, &xfds))
 578             ev.lNetworkEvents |= FD_OOB;
 579
 580           happened = win32_compute_revents_socket ((SOCKET) h, pfd[i].events,
 581                                                    ev.lNetworkEvents);
 582         }
 583       else
 584         {
 585           /* Not a socket.  */
 586           int sought = pfd[i].events;
 587           happened = win32_compute_revents (h, &sought);
 588           nhandles++;
 589         }
 590
 591        if ((pfd[i].revents |= happened) != 0)
 592         rc++;
 593     }
 594
 595   return rc;
 596 #endif
 597 }