compat/poll/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, see <http://www.gnu.org/licenses/>.  */
  20
  21 /* To bump the minimum Windows version to Windows Vista */
  22 #include "git-compat-util.h"
  23
  24 /* Tell gcc not to warn about the (nfd < 0) tests, below.  */
  25 #if (__GNUC__ == 4 && 3 <= __GNUC_MINOR__) || 4 < __GNUC__
  26 # pragma GCC diagnostic ignored "-Wtype-limits"
  27 #endif
  28
  29 #if defined(WIN32)
  30 # include <malloc.h>
  31 #endif
  32
  33 #include <sys/types.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 # if defined (_MSC_VER) && !defined(_WIN32_WINNT)
  42 #  define _WIN32_WINNT 0x0502
  43 # endif
  44 # include <winsock2.h>
  45 # include <windows.h>
  46 # include <io.h>
  47 # include <stdio.h>
  48 # include <conio.h>
  49 #else
  50 # include <sys/time.h>
  51 # include <sys/socket.h>
  52 # ifndef NO_SYS_SELECT_H
  53 #  include <sys/select.h>
  54 # endif
  55 # include <unistd.h>
  56 #endif
  57
  58 /* Specification.  */
  59 #include "poll.h"
  60
  61 #ifdef HAVE_SYS_IOCTL_H
  62 # include <sys/ioctl.h>
  63 #endif
  64 #ifdef HAVE_SYS_FILIO_H
  65 # include <sys/filio.h>
  66 #endif
  67
  68 #include <time.h>
  69
  70 #ifndef INFTIM
  71 # define INFTIM (-1)
  72 #endif
  73
  74 /* BeOS does not have MSG_PEEK.  */
  75 #ifndef MSG_PEEK
  76 # define MSG_PEEK 0
  77 #endif
  78
  79 #ifdef WIN32_NATIVE
  80
  81 #define IsConsoleHandle(h) (((long) (intptr_t) (h) & 3) == 3)
  82
  83 static BOOL
  84 IsSocketHandle (HANDLE h)
  85 {
  86   WSANETWORKEVENTS ev;
  87
  88   if (IsConsoleHandle (h))
  89     return FALSE;
  90
  91   /* Under Wine, it seems that getsockopt returns 0 for pipes too.
  92      WSAEnumNetworkEvents instead distinguishes the two correctly.  */
  93   ev.lNetworkEvents = 0xDEADBEEF;
  94   WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev);
  95   return ev.lNetworkEvents != 0xDEADBEEF;
  96 }
  97
  98 /* Declare data structures for ntdll functions.  */
  99 typedef struct _FILE_PIPE_LOCAL_INFORMATION {
 100   ULONG NamedPipeType;
 101   ULONG NamedPipeConfiguration;
 102   ULONG MaximumInstances;
 103   ULONG CurrentInstances;
 104   ULONG InboundQuota;
 105   ULONG ReadDataAvailable;
 106   ULONG OutboundQuota;
 107   ULONG WriteQuotaAvailable;
 108   ULONG NamedPipeState;
 109   ULONG NamedPipeEnd;
 110 } FILE_PIPE_LOCAL_INFORMATION, *PFILE_PIPE_LOCAL_INFORMATION;
 111
 112 typedef struct _IO_STATUS_BLOCK
 113 {
 114   union {
 115     DWORD Status;
 116     PVOID Pointer;
 117   } u;
 118   ULONG_PTR Information;
 119 } IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;
 120
 121 typedef enum _FILE_INFORMATION_CLASS {
 122   FilePipeLocalInformation = 24
 123 } FILE_INFORMATION_CLASS, *PFILE_INFORMATION_CLASS;
 124
 125 typedef DWORD (WINAPI *PNtQueryInformationFile)
 126          (HANDLE, IO_STATUS_BLOCK *, VOID *, ULONG, FILE_INFORMATION_CLASS);
 127
 128 # ifndef PIPE_BUF
 129 #  define PIPE_BUF      512
 130 # endif
 131
 132 /* Compute revents values for file handle H.  If some events cannot happen
 133    for the handle, eliminate them from *P_SOUGHT.  */
 134
 135 static int
 136 win32_compute_revents (HANDLE h, int *p_sought)
 137 {
 138   int i, ret, happened;
 139   INPUT_RECORD *irbuffer;
 140   DWORD avail, nbuffer;
 141   BOOL bRet;
 142   IO_STATUS_BLOCK iosb;
 143   FILE_PIPE_LOCAL_INFORMATION fpli;
 144   static PNtQueryInformationFile NtQueryInformationFile;
 145   static BOOL once_only;
 146
 147   switch (GetFileType (h))
 148     {
 149     case FILE_TYPE_PIPE:
 150       if (!once_only)
 151         {
 152           NtQueryInformationFile = (PNtQueryInformationFile)(void (*)(void))
 153             GetProcAddress (GetModuleHandle ("ntdll.dll"),
 154                             "NtQueryInformationFile");
 155           once_only = TRUE;
 156         }
 157
 158       happened = 0;
 159       if (PeekNamedPipe (h, NULL, 0, NULL, &avail, NULL) != 0)
 160         {
 161           if (avail)
 162             happened |= *p_sought & (POLLIN | POLLRDNORM);
 163         }
 164       else if (GetLastError () == ERROR_BROKEN_PIPE)
 165         happened |= POLLHUP;
 166
 167       else
 168         {
 169           /* It was the write-end of the pipe.  Check if it is writable.
 170              If NtQueryInformationFile fails, optimistically assume the pipe is
 171              writable.  This could happen on Win9x, where NtQueryInformationFile
 172              is not available, or if we inherit a pipe that doesn't permit
 173              FILE_READ_ATTRIBUTES access on the write end (I think this should
 174              not happen since WinXP SP2; WINE seems fine too).  Otherwise,
 175              ensure that enough space is available for atomic writes.  */
 176           memset (&iosb, 0, sizeof (iosb));
 177           memset (&fpli, 0, sizeof (fpli));
 178
 179           if (!NtQueryInformationFile
 180               || NtQueryInformationFile (h, &iosb, &fpli, sizeof (fpli),
 181                                          FilePipeLocalInformation)
 182               || fpli.WriteQuotaAvailable >= PIPE_BUF
 183               || (fpli.OutboundQuota < PIPE_BUF &&
 184                   fpli.WriteQuotaAvailable == fpli.OutboundQuota))
 185             happened |= *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);
 186         }
 187       return happened;
 188
 189     case FILE_TYPE_CHAR:
 190       ret = WaitForSingleObject (h, 0);
 191       if (!IsConsoleHandle (h))
 192         return ret == WAIT_OBJECT_0 ? *p_sought & ~(POLLPRI | POLLRDBAND) : 0;
 193
 194       nbuffer = avail = 0;
 195       bRet = GetNumberOfConsoleInputEvents (h, &nbuffer);
 196       if (bRet)
 197         {
 198           /* Input buffer.  */
 199           *p_sought &= POLLIN | POLLRDNORM;
 200           if (nbuffer == 0)
 201             return POLLHUP;
 202           if (!*p_sought)
 203             return 0;
 204
 205           irbuffer = (INPUT_RECORD *) alloca (nbuffer * sizeof (INPUT_RECORD));
 206           bRet = PeekConsoleInput (h, irbuffer, nbuffer, &avail);
 207           if (!bRet || avail == 0)
 208             return POLLHUP;
 209
 210           for (i = 0; i < avail; i++)
 211             if (irbuffer[i].EventType == KEY_EVENT)
 212               return *p_sought;
 213           return 0;
 214         }
 215       else
 216         {
 217           /* Screen buffer.  */
 218           *p_sought &= POLLOUT | POLLWRNORM | POLLWRBAND;
 219           return *p_sought;
 220         }
 221
 222     default:
 223       ret = WaitForSingleObject (h, 0);
 224       if (ret == WAIT_OBJECT_0)
 225         return *p_sought & ~(POLLPRI | POLLRDBAND);
 226
 227       return *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);
 228     }
 229 }
 230
 231 /* Convert fd_sets returned by select into revents values.  */
 232
 233 static int
 234 win32_compute_revents_socket (SOCKET h, int sought, long lNetworkEvents)
 235 {
 236   int happened = 0;
 237
 238   if ((lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE)) == FD_ACCEPT)
 239     happened |= (POLLIN | POLLRDNORM) & sought;
 240
 241   else if (lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE))
 242     {
 243       int r, error;
 244
 245       char data[64];
 246       WSASetLastError (0);
 247       r = recv (h, data, sizeof (data), MSG_PEEK);
 248       error = WSAGetLastError ();
 249       WSASetLastError (0);
 250
 251       if (r > 0 || error == WSAENOTCONN)
 252         happened |= (POLLIN | POLLRDNORM) & sought;
 253
 254       /* Distinguish hung-up sockets from other errors.  */
 255       else if (r == 0 || error == WSAESHUTDOWN || error == WSAECONNRESET
 256                || error == WSAECONNABORTED || error == WSAENETRESET)
 257         happened |= POLLHUP;
 258
 259       else
 260         happened |= POLLERR;
 261     }
 262
 263   if (lNetworkEvents & (FD_WRITE | FD_CONNECT))
 264     happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
 265
 266   if (lNetworkEvents & FD_OOB)
 267     happened |= (POLLPRI | POLLRDBAND) & sought;
 268
 269   return happened;
 270 }
 271
 272 #else /* !MinGW */
 273
 274 /* Convert select(2) returned fd_sets into poll(2) revents values.  */
 275 static int
 276 compute_revents (int fd, int sought, fd_set *rfds, fd_set *wfds, fd_set *efds)
 277 {
 278   int happened = 0;
 279   if (FD_ISSET (fd, rfds))
 280     {
 281       int r;
 282       int socket_errno;
 283
 284 # if defined __MACH__ && defined __APPLE__
 285       /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
 286          for some kinds of descriptors.  Detect if this descriptor is a
 287          connected socket, a server socket, or something else using a
 288          0-byte recv, and use ioctl(2) to detect POLLHUP.  */
 289       r = recv (fd, NULL, 0, MSG_PEEK);
 290       socket_errno = (r < 0) ? errno : 0;
 291       if (r == 0 || socket_errno == ENOTSOCK)
 292         ioctl (fd, FIONREAD, &r);
 293 # else
 294       char data[64];
 295       r = recv (fd, data, sizeof (data), MSG_PEEK);
 296       socket_errno = (r < 0) ? errno : 0;
 297 # endif
 298       if (r == 0)
 299         happened |= POLLHUP;
 300
 301       /* If the event happened on an unconnected server socket,
 302          that's fine. */
 303       else if (r > 0 || ( /* (r == -1) && */ socket_errno == ENOTCONN))
 304         happened |= (POLLIN | POLLRDNORM) & sought;
 305
 306       /* Distinguish hung-up sockets from other errors.  */
 307       else if (socket_errno == ESHUTDOWN || socket_errno == ECONNRESET
 308                || socket_errno == ECONNABORTED || socket_errno == ENETRESET)
 309         happened |= POLLHUP;
 310
 311       /* some systems can't use recv() on non-socket, including HP NonStop */
 312       else if (/* (r == -1) && */ socket_errno == ENOTSOCK)
 313         happened |= (POLLIN | POLLRDNORM) & sought;
 314
 315       else
 316         happened |= POLLERR;
 317     }
 318
 319   if (FD_ISSET (fd, wfds))
 320     happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;
 321
 322   if (FD_ISSET (fd, efds))
 323     happened |= (POLLPRI | POLLRDBAND) & sought;
 324
 325   return happened;
 326 }
 327 #endif /* !MinGW */
 328
 329 int
 330 poll (struct pollfd *pfd, nfds_t nfd, int timeout)
 331 {
 332 #ifndef WIN32_NATIVE
 333   fd_set rfds, wfds, efds;
 334   struct timeval tv;
 335   struct timeval *ptv;
 336   int maxfd, rc;
 337   nfds_t i;
 338
 339 # ifdef _SC_OPEN_MAX
 340   static int sc_open_max = -1;
 341
 342   if (nfd < 0
 343       || (nfd > sc_open_max
 344           && (sc_open_max != -1
 345               || nfd > (sc_open_max = sysconf (_SC_OPEN_MAX)))))
 346     {
 347       errno = EINVAL;
 348       return -1;
 349     }
 350 # else /* !_SC_OPEN_MAX */
 351 #  ifdef OPEN_MAX
 352   if (nfd < 0 || nfd > OPEN_MAX)
 353     {
 354       errno = EINVAL;
 355       return -1;
 356     }
 357 #  endif /* OPEN_MAX -- else, no check is needed */
 358 # endif /* !_SC_OPEN_MAX */
 359
 360   /* EFAULT is not necessary to implement, but let's do it in the
 361      simplest case. */
 362   if (!pfd && nfd)
 363     {
 364       errno = EFAULT;
 365       return -1;
 366     }
 367
 368   /* convert timeout number into a timeval structure */
 369   if (timeout == 0)
 370     {
 371       ptv = &tv;
 372       ptv->tv_sec = 0;
 373       ptv->tv_usec = 0;
 374     }
 375   else if (timeout > 0)
 376     {
 377       ptv = &tv;
 378       ptv->tv_sec = timeout / 1000;
 379       ptv->tv_usec = (timeout % 1000) * 1000;
 380     }
 381   else if (timeout == INFTIM)
 382     /* wait forever */
 383     ptv = NULL;
 384   else
 385     {
 386       errno = EINVAL;
 387       return -1;
 388     }
 389
 390   /* create fd sets and determine max fd */
 391   maxfd = -1;
 392   FD_ZERO (&rfds);
 393   FD_ZERO (&wfds);
 394   FD_ZERO (&efds);
 395   for (i = 0; i < nfd; i++)
 396     {
 397       if (pfd[i].fd < 0)
 398         continue;
 399
 400       if (pfd[i].events & (POLLIN | POLLRDNORM))
 401         FD_SET (pfd[i].fd, &rfds);
 402
 403       /* see select(2): "the only exceptional condition detectable
 404          is out-of-band data received on a socket", hence we push
 405          POLLWRBAND events onto wfds instead of efds. */
 406       if (pfd[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND))
 407         FD_SET (pfd[i].fd, &wfds);
 408       if (pfd[i].events & (POLLPRI | POLLRDBAND))
 409         FD_SET (pfd[i].fd, &efds);
 410       if (pfd[i].fd >= maxfd
 411           && (pfd[i].events & (POLLIN | POLLOUT | POLLPRI
 412                                | POLLRDNORM | POLLRDBAND
 413                                | POLLWRNORM | POLLWRBAND)))
 414         {
 415           maxfd = pfd[i].fd;
 416           if (maxfd > FD_SETSIZE)
 417             {
 418               errno = EOVERFLOW;
 419               return -1;
 420             }
 421         }
 422     }
 423
 424   /* examine fd sets */
 425   rc = select (maxfd + 1, &rfds, &wfds, &efds, ptv);
 426   if (rc < 0)
 427     return rc;
 428
 429   /* establish results */
 430   rc = 0;
 431   for (i = 0; i < nfd; i++)
 432     if (pfd[i].fd < 0)
 433       pfd[i].revents = 0;
 434     else
 435       {
 436         int happened = compute_revents (pfd[i].fd, pfd[i].events,
 437                                         &rfds, &wfds, &efds);
 438         if (happened)
 439           {
 440             pfd[i].revents = happened;
 441             rc++;
 442           }
 443         else
 444           {
 445             pfd[i].revents = 0;
 446           }
 447       }
 448
 449   return rc;
 450 #else
 451   static struct timeval tv0;
 452   static HANDLE hEvent;
 453   WSANETWORKEVENTS ev;
 454   HANDLE h, handle_array[FD_SETSIZE + 2];
 455   DWORD ret, wait_timeout, nhandles, orig_timeout = 0;
 456   ULONGLONG start = 0;
 457   fd_set rfds, wfds, xfds;
 458   BOOL poll_again;
 459   MSG msg;
 460   int rc = 0;
 461   nfds_t i;
 462
 463   if (nfd < 0 || timeout < -1)
 464     {
 465       errno = EINVAL;
 466       return -1;
 467     }
 468
 469   if (timeout != INFTIM)
 470     {
 471       orig_timeout = timeout;
 472       start = GetTickCount64();
 473     }
 474
 475   if (!hEvent)
 476     hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
 477
 478 restart:
 479   handle_array[0] = hEvent;
 480   nhandles = 1;
 481   FD_ZERO (&rfds);
 482   FD_ZERO (&wfds);
 483   FD_ZERO (&xfds);
 484
 485   /* Classify socket handles and create fd sets. */
 486   for (i = 0; i < nfd; i++)
 487     {
 488       int sought = pfd[i].events;
 489       pfd[i].revents = 0;
 490       if (pfd[i].fd < 0)
 491         continue;
 492       if (!(sought & (POLLIN | POLLRDNORM | POLLOUT | POLLWRNORM | POLLWRBAND
 493                       | POLLPRI | POLLRDBAND)))
 494         continue;
 495
 496       h = (HANDLE) _get_osfhandle (pfd[i].fd);
 497       assert (h != NULL);
 498       if (IsSocketHandle (h))
 499         {
 500           int requested = FD_CLOSE;
 501
 502           /* see above; socket handles are mapped onto select.  */
 503           if (sought & (POLLIN | POLLRDNORM))
 504             {
 505               requested |= FD_READ | FD_ACCEPT;
 506               FD_SET ((SOCKET) h, &rfds);
 507             }
 508           if (sought & (POLLOUT | POLLWRNORM | POLLWRBAND))
 509             {
 510               requested |= FD_WRITE | FD_CONNECT;
 511               FD_SET ((SOCKET) h, &wfds);
 512             }
 513           if (sought & (POLLPRI | POLLRDBAND))
 514             {
 515               requested |= FD_OOB;
 516               FD_SET ((SOCKET) h, &xfds);
 517             }
 518
 519           if (requested)
 520             WSAEventSelect ((SOCKET) h, hEvent, requested);
 521         }
 522       else
 523         {
 524           /* Poll now.  If we get an event, do not poll again.  Also,
 525              screen buffer handles are waitable, and they'll block until
 526              a character is available.  win32_compute_revents eliminates
 527              bits for the "wrong" direction. */
 528           pfd[i].revents = win32_compute_revents (h, &sought);
 529           if (sought)
 530             handle_array[nhandles++] = h;
 531           if (pfd[i].revents)
 532             timeout = 0;
 533         }
 534     }
 535
 536   if (select (0, &rfds, &wfds, &xfds, &tv0) > 0)
 537     {
 538       /* Do MsgWaitForMultipleObjects anyway to dispatch messages, but
 539          no need to call select again.  */
 540       poll_again = FALSE;
 541       wait_timeout = 0;
 542     }
 543   else
 544     {
 545       poll_again = TRUE;
 546       if (timeout == INFTIM)
 547         wait_timeout = INFINITE;
 548       else
 549         wait_timeout = timeout;
 550     }
 551
 552   for (;;)
 553     {
 554       ret = MsgWaitForMultipleObjects (nhandles, handle_array, FALSE,
 555                                        wait_timeout, QS_ALLINPUT);
 556
 557       if (ret == WAIT_OBJECT_0 + nhandles)
 558         {
 559           /* new input of some other kind */
 560           BOOL bRet;
 561           while ((bRet = PeekMessage (&msg, NULL, 0, 0, PM_REMOVE)) != 0)
 562             {
 563               TranslateMessage (&msg);
 564               DispatchMessage (&msg);
 565             }
 566         }
 567       else
 568         break;
 569     }
 570
 571   if (poll_again)
 572     select (0, &rfds, &wfds, &xfds, &tv0);
 573
 574   /* Place a sentinel at the end of the array.  */
 575   handle_array[nhandles] = NULL;
 576   nhandles = 1;
 577   for (i = 0; i < nfd; i++)
 578     {
 579       int happened;
 580
 581       if (pfd[i].fd < 0)
 582         continue;
 583       if (!(pfd[i].events & (POLLIN | POLLRDNORM |
 584                              POLLOUT | POLLWRNORM | POLLWRBAND)))
 585         continue;
 586
 587       h = (HANDLE) _get_osfhandle (pfd[i].fd);
 588       if (h != handle_array[nhandles])
 589         {
 590           /* It's a socket.  */
 591           WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev);
 592           WSAEventSelect ((SOCKET) h, NULL, 0);
 593
 594           /* If we're lucky, WSAEnumNetworkEvents already provided a way
 595              to distinguish FD_READ and FD_ACCEPT; this saves a recv later.  */
 596           if (FD_ISSET ((SOCKET) h, &rfds)
 597               && !(ev.lNetworkEvents & (FD_READ | FD_ACCEPT)))
 598             ev.lNetworkEvents |= FD_READ | FD_ACCEPT;
 599           if (FD_ISSET ((SOCKET) h, &wfds))
 600             ev.lNetworkEvents |= FD_WRITE | FD_CONNECT;
 601           if (FD_ISSET ((SOCKET) h, &xfds))
 602             ev.lNetworkEvents |= FD_OOB;
 603
 604           happened = win32_compute_revents_socket ((SOCKET) h, pfd[i].events,
 605                                                    ev.lNetworkEvents);
 606         }
 607       else
 608         {
 609           /* Not a socket.  */
 610           int sought = pfd[i].events;
 611           happened = win32_compute_revents (h, &sought);
 612           nhandles++;
 613         }
 614
 615        if ((pfd[i].revents |= happened) != 0)
 616         rc++;
 617     }
 618
 619   if (!rc && orig_timeout && timeout != INFTIM)
 620     {
 621       ULONGLONG elapsed = GetTickCount64() - start;
 622       timeout = elapsed >= orig_timeout ? 0 : (int)(orig_timeout - elapsed);
 623     }
 624
 625   if (!rc && timeout)
 626     {
 627       SleepEx (1, TRUE);
 628       goto restart;
 629     }
 630
 631   return rc;
 632 #endif
 633 }