src/lwp/iomgr.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*******************************************************************\
  11 *                                                                   *
  12 *       Information Technology Center                               *
  13 *       Carnegie-Mellon University                                  *
  14 *                                                                   *
  15 *                                                                   *
  16 *                                                                   *
  17 \*******************************************************************/
  18
  19
  20 /*
  21         IO Manager routines & server process for VICE server.
  22 */
  23
  24 /* This controls the size of an fd_set; it must be defined early before
  25  * the system headers define that type and the macros that operate on it.
  26  * Its value should be as large as the maximum file descriptor limit we
  27  * are likely to run into on any platform.  Right now, that is 65536
  28  * which is the default hard fd limit on Solaris 9 */
  29 /* We don't do this on Windows because on that platform there is code
  30  * which allocates fd_set's on the stack (IOMGR_Sleep on Win9x, and
  31  * FDSetAnd on WinNT) */
  32 #ifndef _WIN32
  33 #define FD_SETSIZE 65536
  34 #endif
  35
  36 #include <afsconfig.h>
  37 #include <afs/param.h>
  38
  39 #include <roken.h>
  40
  41 #ifdef HAVE_SYS_SELECT_H
  42 #include <sys/select.h>
  43 #endif
  44
  45 #include <afs/opr.h>
  46
  47 #include "lwp.h"
  48 #include "timer.h"
  49
  50 typedef unsigned char bool;
  51 #define FALSE   0
  52 #define TRUE    1
  53
  54 #ifndef MIN
  55 #define MIN(a,b) (((a)>(b)) ? (b) : (a))
  56 #endif
  57
  58 #ifndef NSIG
  59 #define NSIG 8*sizeof(sigset_t)
  60 #endif
  61
  62 static int SignalSignals(void);
  63
  64 /********************************\
  65 *                                *
  66 *  Stuff for managing IoRequests *
  67 *                                *
  68 \********************************/
  69
  70 struct IoRequest {
  71
  72     /* Pid of process making request (for use in IOMGR_Cancel */
  73     PROCESS             pid;
  74
  75     /* Descriptor masks for requests */
  76     int                 nfds;
  77     fd_set              *readfds;
  78     fd_set              *writefds;
  79     fd_set              *exceptfds;
  80
  81     struct TM_Elem      timeout;
  82
  83     /* Result of select call */
  84     int                 result;
  85
  86     struct IoRequest    *next;  /* for iorFreeList */
  87
  88 };
  89
  90 /********************************\
  91 *                                *
  92 *  Stuff for managing signals    *
  93 *                                *
  94 \********************************/
  95
  96 #define badsig(signo)           (((signo) <= 0) || ((signo) >= NSIG))
  97 #define mysigmask(signo)                (1 << ((signo)-1))
  98
  99
 100 fd_set openMask;                /* mask of open files on an IOMGR abort */
 101 static afs_int32 sigsHandled;   /* sigmask(signo) is on if we handle signo */
 102 static int anySigsDelivered;            /* true if any have been delivered. */
 103 #ifndef AFS_NT40_ENV
 104 static struct sigaction oldActions[NSIG];       /* the old signal vectors */
 105 #endif
 106 static char *sigEvents[NSIG];           /* the event to do an LWP signal on */
 107 static int sigDelivered[NSIG];          /* True for signals delivered so far.
 108                                            This is an int array to make sure
 109                                            there are no conflicts when trying
 110                                            to write it */
 111 /* software 'signals' */
 112 #define NSOFTSIG                4
 113 static void *(*sigProc[NSOFTSIG])(void *);
 114 static void *sigRock[NSOFTSIG];
 115
 116
 117 static struct IoRequest *iorFreeList = 0;
 118
 119 static struct TM_Elem *Requests;        /* List of requests */
 120 static struct timeval iomgr_timeout;    /* global so signal handler can zap it */
 121
 122 /* stuff for debugging */
 123 static int iomgr_errno;
 124 static struct timeval iomgr_badtv;
 125 static PROCESS iomgr_badpid;
 126 static void SignalIO(int fds, fd_set *rfds, fd_set *wfds, fd_set *efs,
 127                     int code);
 128 static void SignalTimeout(int code, struct timeval *timeout);
 129
 130 /* fd_set pool managment.
 131  * Use the pool instead of creating fd_set's on the stack. fd_set's can be
 132  * 8K in size, so making three could put 24K in the limited space of an LWP
 133  * stack.
 134  */
 135 struct IOMGR_fd_set {
 136     struct IOMGR_fd_set *next;
 137 } *iomgrFreeFDSets = (struct IOMGR_fd_set*)0;
 138
 139 /* IOMGR_FreeFDSet
 140  * Return fd_set to the free list.
 141  */
 142 void IOMGR_FreeFDSet(fd_set *s)
 143 {
 144     struct IOMGR_fd_set *t = (struct IOMGR_fd_set *)s;
 145
 146     t->next = iomgrFreeFDSets;
 147     iomgrFreeFDSets = t;
 148 }
 149
 150 /* IOMGR_AllocFDSet
 151  * returns a zeroed fd_set or null if could not malloc one.
 152  */
 153 fd_set *IOMGR_AllocFDSet(void)
 154 {
 155     fd_set *t;
 156     if (iomgrFreeFDSets) {
 157         t = (fd_set *) iomgrFreeFDSets;
 158         iomgrFreeFDSets = iomgrFreeFDSets->next;
 159     }
 160     else {
 161         t = malloc(sizeof(fd_set));
 162     }
 163     if (!t)
 164         return NULL;
 165     else {
 166         FD_ZERO(t);
 167         return t;
 168     }
 169 }
 170
 171 #define FreeRequest(x) ((x)->next = iorFreeList, iorFreeList = (x))
 172
 173 static struct IoRequest *NewRequest(void)
 174 {
 175     struct IoRequest *request;
 176
 177     if ((request=iorFreeList)) {
 178         iorFreeList = (struct IoRequest *) (request->next);
 179         memset(request, 0, sizeof(struct IoRequest));
 180     } else request = calloc(1, sizeof(struct IoRequest));
 181
 182     return request;
 183 }
 184
 185 #define Purge(list) FOR_ALL_ELTS(req, list, { free(req->BackPointer); })
 186
 187
 188 /* FD_SET support routines. All assume the fd_set size is a multiple of an int
 189  * so we can at least do logical operations on ints instead of chars.
 190  *
 191  * For each routine, nfds is the highest bit set in either fd_set, starting
 192  * with no bits == 0.
 193  */
 194 #ifdef AFS_NT40_ENV
 195 #define FD_N_ZERO(A, x) FD_ZERO(x)
 196 #else
 197 #define FDS_P_POS (sizeof(int)*8)
 198 #define INTS_PER_FDS(x) (((x)+(FDS_P_POS-1)) / FDS_P_POS)
 199 #define FD_N_ZERO(nfds, x) memset((char*)(x), 0, (INTS_PER_FDS(nfds))*sizeof(int))
 200 #endif
 201
 202 /* On Linux without __USE_XOPEN, we have __fds_bits. With __USE_XOPEN, or
 203  * non-Linux, we have fds_bits. */
 204 #if defined(AFS_LINUX22_ENV) && (__GLIBC_MINOR__ > 0) && !defined(__USE_XOPEN)
 205 # define FDS_BITS __fds_bits
 206 #else
 207 # define FDS_BITS fds_bits
 208 #endif
 209
 210 /* FDSetCmp - returns 1 if any bits in fd_set1 are also set in fd_set2.
 211  * If nfds is 0, or one of the fd_sets is null return 0 (since there is no bit
 212  * set in both fd_sets).
 213  */
 214 static int FDSetCmp(int nfds, fd_set *fd_set1, fd_set *fd_set2)
 215 {
 216     unsigned int i, j;
 217
 218     if (fd_set1 == (fd_set*)0 || fd_set2 == (fd_set*)0)
 219         return 0;
 220
 221 #ifdef AFS_NT40_ENV
 222     if (fd_set1->fd_count == 0 || fd_set2->fd_count == 0)
 223         return 0;
 224
 225     for (i=0; i<fd_set1->fd_count; i++) {
 226         for (j=0; j<fd_set2->fd_count; j++) {
 227         if (fd_set1->fd_array[i] == fd_set2->fd_array[j])
 228             return 1;
 229         }
 230     }
 231 #else
 232     if (nfds == 0)
 233         return 0;
 234
 235     j = INTS_PER_FDS(nfds);
 236     for (i=0; i<j; i++) {
 237         if (fd_set1->FDS_BITS[i] & fd_set2->FDS_BITS[i])
 238             return 1;
 239     }
 240 #endif
 241     return 0;
 242 }
 243
 244 /* FDSetSet - set bits from fd_set2 into fd_set1
 245  */
 246 static void FDSetSet(int nfds, fd_set *fd_set1, fd_set *fd_set2)
 247 {
 248     unsigned int i;
 249 #ifndef AFS_NT40_ENV
 250     unsigned int n;
 251 #endif
 252
 253     if (fd_set1 == (fd_set*)0 || fd_set2 == (fd_set*)0)
 254         return;
 255
 256 #ifdef AFS_NT40_ENV
 257     if (fd_set2->fd_count==0)
 258         return;
 259
 260     for (i=0; i<fd_set2->fd_count; i++)
 261         FD_SET(fd_set2->fd_array[i], fd_set1);
 262 #else
 263     if (nfds == 0)
 264         return;
 265
 266     for (i = 0, n = INTS_PER_FDS(nfds); i < n; i++) {
 267         fd_set1->FDS_BITS[i] |= fd_set2->FDS_BITS[i];
 268     }
 269 #endif
 270 }
 271
 272 /* FDSetAnd - fd_set1  <- fd_set1 & fd_set2.
 273  */
 274 #ifdef AFS_NT40_ENV
 275 static void FDSetAnd(int nfds, fd_set *fd_set1, fd_set *fd_set2)
 276 {
 277     unsigned int i;
 278     fd_set tmpset;
 279
 280     if (fd_set1 == NULL || fd_set1->fd_count == 0)
 281         return;
 282
 283     if (fd_set2 == NULL || fd_set2->fd_count == 0) {
 284         FD_ZERO(fd_set1);
 285     }
 286     else {
 287         FD_ZERO(&tmpset);
 288         for (i=0; i<fd_set2->fd_count; i++) {
 289             if (FD_ISSET(fd_set2->fd_array[i], fd_set1))
 290                 FD_SET(fd_set2->fd_array[i], &tmpset);
 291         }
 292         *fd_set1 = tmpset;
 293     }
 294 }
 295 #else
 296 static void FDSetAnd(int nfds, fd_set *fd_set1, fd_set *fd_set2)
 297 {
 298     int i, n;
 299
 300     if (nfds == 0 || fd_set1 == (fd_set*)0 || fd_set2 == (fd_set*)0)
 301         return;
 302
 303     n = INTS_PER_FDS(nfds);
 304     for (i=0; i<n; i++) {
 305         fd_set1->FDS_BITS[i] &= fd_set2->FDS_BITS[i];
 306     }
 307 }
 308 #endif
 309
 310 /* FDSetEmpty - return true if fd_set is empty
 311  */
 312 static int FDSetEmpty(int nfds, fd_set *fds)
 313 {
 314 #ifndef AFS_NT40_ENV
 315     int i, n;
 316
 317     if (nfds == 0)
 318         return 1;
 319 #endif
 320     if (fds == (fd_set*)0)
 321         return 1;
 322
 323 #ifdef AFS_NT40_ENV
 324     if (fds->fd_count == 0)
 325         return 1;
 326     else
 327         return 0;
 328 #else
 329     n = INTS_PER_FDS(nfds);
 330
 331     for (i=n-1; i>=0; i--) {
 332         if (fds->FDS_BITS[i])
 333             break;
 334     }
 335
 336     if (i>=0)
 337         return 0;
 338     else
 339         return 1;
 340 #endif
 341 }
 342
 343 /* The IOMGR process */
 344
 345 /*
 346  * Important invariant: process->iomgrRequest is null iff request not in timer
 347  * queue.
 348  * also, request->pid is valid while request is in queue,
 349  * also, don't signal selector while request in queue, since selector frees
 350  *  request.
 351  */
 352
 353 /* These are not declared in IOMGR so that they don't use up 6K of stack. */
 354 static fd_set IOMGR_readfds, IOMGR_writefds, IOMGR_exceptfds;
 355 static int IOMGR_nfds = 0;
 356
 357 static void *IOMGR(void *dummy)
 358 {
 359     for (;;) {
 360         int code;
 361         struct TM_Elem *earliest;
 362         struct timeval timeout, junk;
 363         bool woke_someone;
 364
 365         FD_ZERO(&IOMGR_readfds);
 366         FD_ZERO(&IOMGR_writefds);
 367         FD_ZERO(&IOMGR_exceptfds);
 368         IOMGR_nfds = 0;
 369
 370         /* Wake up anyone who has expired or who has received a
 371            Unix signal between executions.  Keep going until we
 372            run out. */
 373         do {
 374             woke_someone = FALSE;
 375             /* Wake up anyone waiting on signals. */
 376             /* Note: SignalSignals() may yield! */
 377             if (anySigsDelivered && SignalSignals ())
 378                 woke_someone = TRUE;
 379             FT_GetTimeOfDay(&junk, 0);    /* force accurate time check */
 380             TM_Rescan(Requests);
 381             for (;;) {
 382                 struct IoRequest *req;
 383                 struct TM_Elem *expired;
 384                 expired = TM_GetExpired(Requests);
 385                 if (expired == NULL) break;
 386                 woke_someone = TRUE;
 387                 req = (struct IoRequest *) expired -> BackPointer;
 388 #ifdef DEBUG
 389                 if (lwp_debug != 0) puts("[Polling SELECT]");
 390 #endif /* DEBUG */
 391                 /* no data ready */
 392                 if (req->readfds)   FD_N_ZERO(req->nfds, req->readfds);
 393                 if (req->writefds)  FD_N_ZERO(req->nfds, req->writefds);
 394                 if (req->exceptfds) FD_N_ZERO(req->nfds, req->exceptfds);
 395                 req->nfds = 0;
 396                 req->result = 0; /* no fds ready */
 397                 TM_Remove(Requests, &req->timeout);
 398 #ifdef DEBUG
 399                 req -> timeout.Next = (struct TM_Elem *) 2;
 400                 req -> timeout.Prev = (struct TM_Elem *) 2;
 401 #endif /* DEBUG */
 402                 LWP_QSignal(req->pid);
 403                 req->pid->iomgrRequest = 0;
 404             }
 405
 406             if (woke_someone) LWP_DispatchProcess();
 407         } while (woke_someone);
 408
 409         /* Collect requests & update times */
 410         FD_ZERO(&IOMGR_readfds);
 411         FD_ZERO(&IOMGR_writefds);
 412         FD_ZERO(&IOMGR_exceptfds);
 413         IOMGR_nfds = 0;
 414
 415         FOR_ALL_ELTS(r, Requests, {
 416             struct IoRequest *req;
 417             req = (struct IoRequest *) r -> BackPointer;
 418             FDSetSet(req->nfds, &IOMGR_readfds,   req->readfds);
 419             FDSetSet(req->nfds, &IOMGR_writefds,  req->writefds);
 420             FDSetSet(req->nfds, &IOMGR_exceptfds, req->exceptfds);
 421             if (req->nfds > IOMGR_nfds)
 422                 IOMGR_nfds = req->nfds;
 423         })
 424         earliest = TM_GetEarliest(Requests);
 425         if (earliest != NULL) {
 426             timeout = earliest -> TimeLeft;
 427
 428
 429             /* Do select */
 430 #ifdef DEBUG
 431             if (lwp_debug != 0) {
 432 #ifdef AFS_NT40_ENV
 433                 int idbg;
 434                 printf("[Read Select:");
 435                 if (IOMGR_readfds.fd_count == 0)
 436                     printf(" none]\n");
 437                 else {
 438                     for (idbg=0; idbg<IOMGR_readfds.fd_count; idbg++)
 439                         printf(" %d", IOMGR_readfds.fd_array[idbg]);
 440                     printf("]\n");
 441                 }
 442                 printf("[Write Select:");
 443                 if (IOMGR_writefds.fd_count == 0)
 444                     printf(" none]\n");
 445                 else {
 446                     for (idbg=0; idbg<IOMGR_writefds.fd_count; idbg++)
 447                         printf(" %d", IOMGR_writefds.fd_array[idbg]);
 448                     printf("]\n");
 449                 }
 450                 printf("[Except Select:");
 451                 if (IOMGR_exceptfds.fd_count == 0)
 452                     printf(" none]\n");
 453                 else {
 454                     for (idbg=0; idbg<IOMGR_exceptfds.fd_count; idbg++)
 455                         printf(" %d", IOMGR_exceptfds.fd_array[idbg]);
 456                     printf("]\n");
 457                 }
 458 #else
 459                 /* Only prints first 32. */
 460                 printf("[select(%d, 0x%x, 0x%x, 0x%x, ", IOMGR_nfds,
 461                        *(int*)&IOMGR_readfds, *(int*)&IOMGR_writefds,
 462                        *(int*)&IOMGR_exceptfds);
 463 #endif /* AFS_NT40_ENV */
 464                 if (timeout.tv_sec == -1 && timeout.tv_usec == -1)
 465                     puts("INFINITE)]");
 466                 else
 467                     printf("<%d, %d>)]\n", timeout.tv_sec, timeout.tv_usec);
 468             }
 469 #endif /* DEBUG */
 470             iomgr_timeout = timeout;
 471             if (timeout.tv_sec == -1 && timeout.tv_usec == -1) {
 472                 /* infinite, sort of */
 473                 iomgr_timeout.tv_sec = 100000000;
 474                 iomgr_timeout.tv_usec = 0;
 475             }
 476 #if defined(AFS_NT40_ENV) || defined(AFS_LINUX24_ENV)
 477             /* On NT, signals don't interrupt a select call. So this can potentially
 478              * lead to long wait times before a signal is honored. To avoid this we
 479              * dont do select() for longer than IOMGR_MAXWAITTIME (5 secs) */
 480             /* Whereas Linux seems to sometimes "lose" signals */
 481             if (iomgr_timeout.tv_sec > (IOMGR_MAXWAITTIME - 1)) {
 482               iomgr_timeout.tv_sec = IOMGR_MAXWAITTIME;
 483               iomgr_timeout.tv_usec = 0;
 484             }
 485 #endif /* NT40 */
 486
 487             /* Check one last time for a signal delivery.  If one comes after
 488                this, the signal handler will set iomgr_timeout to zero, causing
 489                the select to return immediately.  The timer package won't return
 490                a zero timeval because all of those guys were handled above.
 491
 492                I'm assuming that the kernel masks signals while it's picking up
 493                the parameters to select.  This may a bad assumption.  -DN */
 494             if (anySigsDelivered)
 495                 continue;       /* go to the top and handle them. */
 496
 497 #ifdef AFS_NT40_ENV
 498             if (IOMGR_readfds.fd_count == 0 && IOMGR_writefds.fd_count == 0
 499                 && IOMGR_exceptfds.fd_count == 0) {
 500                 DWORD stime;
 501                 code = 0;
 502                 if (iomgr_timeout.tv_sec || iomgr_timeout.tv_usec) {
 503                     stime = iomgr_timeout.tv_sec * 1000
 504                         + iomgr_timeout.tv_usec/1000;
 505                     if (!stime)
 506                         stime = 1;
 507                     Sleep(stime);
 508                 }
 509             }
 510             else
 511 #endif
 512                 {    /* select runs much faster if 0's are passed instead of &0s */
 513                     code = select(IOMGR_nfds,
 514                                   (FDSetEmpty(IOMGR_nfds, &IOMGR_readfds)) ?
 515                                   (fd_set*)0 : &IOMGR_readfds,
 516                                   (FDSetEmpty(IOMGR_nfds, &IOMGR_writefds)) ?
 517                                   (fd_set*)0 : &IOMGR_writefds,
 518                                   (FDSetEmpty(IOMGR_nfds, &IOMGR_exceptfds)) ?
 519                                   (fd_set*)0 : &IOMGR_exceptfds,
 520                                   &iomgr_timeout);
 521                 }
 522
 523             if (code < 0) {
 524                int e=1;
 525
 526 #if defined(AFS_SUN_ENV)
 527                /* Tape drives on Sun boxes do not support select and return ENXIO */
 528                if (errno == ENXIO) e=0, code=1;
 529 #endif
 530 #if defined(AFS_SGI_ENV) || defined(AFS_SUN5_ENV) || defined(AFS_OSF_ENV) || defined(AFS_AIX32_ENV)
 531                /* For SGI and SVR4 - poll & select can return EAGAIN ... */
 532                if (errno == EAGAIN) e=0;
 533 #endif
 534 #if defined(AFS_SUN5_ENV)
 535                /* On sun4x_55, select doesn't block signal. It could be
 536                   interupted by a signal that changes iomgr_timeout, and
 537                   then select returns with EINVAL. In this case, we need
 538                   to retry.
 539                 */
 540                if (errno==EINVAL && anySigsDelivered)
 541                    e = 0;
 542 #endif /* AFS_SUN5_ENV */
 543
 544                if ((errno != EINTR) && e) {
 545 #ifndef AFS_NT40_ENV
 546                   int i;
 547                   for(i=0; i<FD_SETSIZE; i++) {
 548                      if (fcntl(i, F_GETFD, 0) < 0 && errno == EBADF)
 549                          FD_SET(i, &openMask);
 550                   }
 551 #endif
 552                   iomgr_errno = errno;
 553                   opr_abort();
 554                }
 555             }
 556
 557             /* See what happened */
 558             if (code > 0) {
 559                 /* Action -- wake up everyone involved */
 560                 SignalIO(IOMGR_nfds, &IOMGR_readfds, &IOMGR_writefds,
 561                          &IOMGR_exceptfds, code);
 562             }
 563             else if (code == 0
 564                 && (iomgr_timeout.tv_sec != 0 || iomgr_timeout.tv_usec != 0)) {
 565                 /* Real timeout only if signal handler hasn't set
 566                    iomgr_timeout to zero. */
 567
 568 #if defined(AFS_NT40_ENV) || defined(AFS_LINUX24_ENV)
 569                 /* On NT, real timeout only if above and if iomgr_timeout
 570                  * interval is equal to timeout interval (i.e., not adjusted
 571                  * to check for pseudo-signals).
 572                  */
 573                 /* And also for Linux as above */
 574                 if (iomgr_timeout.tv_sec  != timeout.tv_sec ||
 575                     iomgr_timeout.tv_usec != timeout.tv_usec) {
 576                     /* signal check interval timed out; not real timeout */
 577                     continue;
 578                 }
 579 #endif /* AFS_NT40_ENV */
 580                 FT_GetTimeOfDay(&junk, 0);
 581                 SignalTimeout(code, &timeout);
 582             }
 583         }
 584         LWP_DispatchProcess();
 585     }
 586     AFS_UNREACHED(return((void *)-1)); /* keeps compilers happy. */
 587 }
 588
 589 /************************\
 590 *                        *
 591 *  Signalling routines   *
 592 *                        *
 593 \************************/
 594
 595 static void SignalIO(int fds, fd_set *readfds, fd_set *writefds,
 596                      fd_set *exceptfds, int code)
 597 {
 598     int nfds;
 599     /* Look at everyone who's bit mask was affected */
 600     FOR_ALL_ELTS(r, Requests, {
 601         struct IoRequest *req;
 602         PROCESS pid;
 603         req = (struct IoRequest *) r -> BackPointer;
 604         nfds = MIN(fds, req->nfds);
 605         if (FDSetCmp(nfds, req->readfds, readfds) ||
 606             FDSetCmp(nfds, req->writefds, writefds) ||
 607             FDSetCmp(nfds, req->exceptfds, exceptfds)) {
 608             /* put ready fd's into request. */
 609             FDSetAnd(nfds, req->readfds, readfds);
 610             FDSetAnd(nfds, req->writefds, writefds);
 611             FDSetAnd(nfds, req->exceptfds, exceptfds);
 612             req -> result = code;
 613             TM_Remove(Requests, &req->timeout);
 614             LWP_QSignal(pid=req->pid);
 615             pid->iomgrRequest = 0;
 616         }
 617     })
 618 }
 619
 620 static void SignalTimeout(int code, struct timeval *timeout)
 621 {
 622     /* Find everyone who has specified timeout */
 623     FOR_ALL_ELTS(r, Requests, {
 624         struct IoRequest *req;
 625         PROCESS pid;
 626         req = (struct IoRequest *) r -> BackPointer;
 627         if (TM_eql(&r->TimeLeft, timeout)) {
 628             req -> result = code;
 629             TM_Remove(Requests, &req->timeout);
 630             LWP_QSignal(pid=req->pid);
 631             pid->iomgrRequest = 0;
 632         } else
 633             return;
 634     })
 635 }
 636
 637 /*****************************************************\
 638 *                                                     *
 639 *  Signal handling routine (not to be confused with   *
 640 *  signalling routines, above).                       *
 641 *                                                     *
 642 \*****************************************************/
 643 static void SigHandler (int signo)
 644 {
 645     if (badsig(signo) || (sigsHandled & mysigmask(signo)) == 0)
 646         return;         /* can't happen. */
 647     sigDelivered[signo] = TRUE;
 648     anySigsDelivered = TRUE;
 649     /* Make sure that the IOMGR process doesn't pause on the select. */
 650     iomgr_timeout.tv_sec = 0;
 651     iomgr_timeout.tv_usec = 0;
 652 }
 653
 654 /* Alright, this is the signal signalling routine.  It delivers LWP signals
 655    to LWPs waiting on Unix signals. NOW ALSO CAN YIELD!! */
 656 static int SignalSignals (void)
 657 {
 658     bool gotone = FALSE;
 659     int i;
 660     void *(*p)(void *);
 661     afs_int32 stackSize;
 662
 663     anySigsDelivered = FALSE;
 664
 665     /* handle software signals */
 666     stackSize = (AFS_LWP_MINSTACKSIZE < lwp_MaxStackSeen? lwp_MaxStackSeen : AFS_LWP_MINSTACKSIZE);
 667     for (i=0; i < NSOFTSIG; i++) {
 668         PROCESS pid;
 669         if ((p=sigProc[i])) /* This yields!!! */
 670             LWP_CreateProcess2(p, stackSize, LWP_NORMAL_PRIORITY,
 671                                sigRock[i], "SignalHandler", &pid);
 672         sigProc[i] = 0;
 673     }
 674
 675     for (i = 1; i < NSIG; ++i)  /* forall !badsig(i) */
 676         if ((sigsHandled & mysigmask(i)) && sigDelivered[i] == TRUE) {
 677             sigDelivered[i] = FALSE;
 678             LWP_NoYieldSignal (sigEvents[i]);
 679             gotone = TRUE;
 680         }
 681     return gotone;
 682 }
 683
 684
 685 /***************************\
 686 *                           *
 687 *  User-callable routines   *
 688 *                           *
 689 \***************************/
 690
 691
 692 /* Keep IOMGR process id */
 693 static PROCESS IOMGR_Id = NULL;
 694
 695 int IOMGR_SoftSig(void *(*aproc)(void *), void *arock)
 696 {
 697     int i;
 698     for (i=0;i<NSOFTSIG;i++) {
 699         if (sigProc[i] == 0) {
 700             /* a free entry */
 701             sigProc[i] = aproc;
 702             sigRock[i] = arock;
 703             anySigsDelivered = TRUE;
 704             iomgr_timeout.tv_sec = 0;
 705             iomgr_timeout.tv_usec = 0;
 706             return 0;
 707         }
 708     }
 709     return -1;
 710 }
 711
 712
 713 int IOMGR_Initialize(void)
 714 {
 715     PROCESS pid;
 716
 717     /* If lready initialized, just return */
 718     if (IOMGR_Id != NULL) return LWP_SUCCESS;
 719
 720     /* Init LWP if someone hasn't yet. */
 721     if (LWP_InitializeProcessSupport (LWP_NORMAL_PRIORITY, &pid) != LWP_SUCCESS)
 722         return -1;
 723
 724     /* Initialize request lists */
 725     if (TM_Init(&Requests) < 0) return -1;
 726
 727     /* Initialize signal handling stuff. */
 728     sigsHandled = 0;
 729     anySigsDelivered = TRUE; /* A soft signal may have happened before
 730         IOMGR_Initialize:  so force a check for signals regardless */
 731
 732     return LWP_CreateProcess(IOMGR, AFS_LWP_MINSTACKSIZE, 0, (void *) 0,
 733                              "IO MANAGER", &IOMGR_Id);
 734 }
 735
 736 int IOMGR_Finalize(void)
 737 {
 738     int status;
 739
 740     Purge(Requests)
 741     TM_Final(&Requests);
 742     status = LWP_DestroyProcess(IOMGR_Id);
 743     IOMGR_Id = NULL;
 744     return status;
 745 }
 746
 747 /* signal I/O for anyone who is waiting for a FD or a timeout; not too cheap,
 748  * since forces select and timeofday check */
 749 int IOMGR_Poll(void) {
 750     fd_set *readfds, *writefds, *exceptfds;
 751     afs_int32 code;
 752     struct timeval tv;
 753     int fds;
 754
 755     FT_GetTimeOfDay(&tv, 0);    /* force accurate time check */
 756     TM_Rescan(Requests);
 757     for (;;) {
 758         struct IoRequest *req;
 759         struct TM_Elem *expired;
 760         expired = TM_GetExpired(Requests);
 761         if (expired == NULL) break;
 762         req = (struct IoRequest *) expired -> BackPointer;
 763 #ifdef DEBUG
 764         if (lwp_debug != 0) puts("[Polling SELECT]");
 765 #endif /* DEBUG */
 766         /* no data ready */
 767         if (req->readfds)   FD_N_ZERO(req->nfds, req->readfds);
 768         if (req->writefds)  FD_N_ZERO(req->nfds, req->writefds);
 769         if (req->exceptfds) FD_N_ZERO(req->nfds, req->exceptfds);
 770         req->nfds = 0;
 771         req->result = 0; /* no fds ready */
 772         TM_Remove(Requests, &req->timeout);
 773 #ifdef DEBUG
 774         req -> timeout.Next = (struct TM_Elem *) 2;
 775         req -> timeout.Prev = (struct TM_Elem *) 2;
 776 #endif /* DEBUG */
 777         LWP_QSignal(req->pid);
 778         req->pid->iomgrRequest = 0;
 779     }
 780
 781     /* Collect requests & update times */
 782     readfds = IOMGR_AllocFDSet();
 783     writefds = IOMGR_AllocFDSet();
 784     exceptfds = IOMGR_AllocFDSet();
 785     if (!(readfds && writefds && exceptfds)) {
 786         fprintf(stderr, "IOMGR_Poll: Could not malloc space for fd_sets.\n");
 787         fflush(stderr);
 788     }
 789
 790     fds = 0;
 791
 792     FOR_ALL_ELTS(r, Requests, {
 793         struct IoRequest *req;
 794         req = (struct IoRequest *) r -> BackPointer;
 795         FDSetSet(req->nfds, readfds,   req->readfds);
 796         FDSetSet(req->nfds, writefds,  req->writefds);
 797         FDSetSet(req->nfds, exceptfds, req->exceptfds);
 798         if (fds < req->nfds)
 799             fds = req->nfds;
 800     })
 801
 802     tv.tv_sec = 0;
 803     tv.tv_usec = 0;
 804 #ifdef AFS_NT40_ENV
 805     code = -1;
 806     if (readfds->fd_count == 0 && writefds->fd_count == 0
 807         && exceptfds->fd_count == 0)
 808 #endif
 809         code = select(fds, readfds, writefds, exceptfds, &tv);
 810     if (code > 0) {
 811         SignalIO(fds, readfds, writefds, exceptfds, code);
 812     }
 813
 814     if (readfds) IOMGR_FreeFDSet(readfds);
 815     if (writefds) IOMGR_FreeFDSet(writefds);
 816     if (exceptfds) IOMGR_FreeFDSet(exceptfds);
 817
 818
 819     LWP_DispatchProcess();  /* make sure others run */
 820     LWP_DispatchProcess();
 821     return 0;
 822 }
 823
 824 int IOMGR_Select(int fds, fd_set *readfds, fd_set *writefds,
 825                  fd_set *exceptfds, struct timeval *timeout)
 826 {
 827     struct IoRequest *request;
 828     int result;
 829
 830 #ifndef AFS_NT40_ENV
 831     if(fds > FD_SETSIZE) {
 832         fprintf(stderr, "IOMGR_Select: fds=%d, more than max %d\n",
 833                 fds, FD_SETSIZE);
 834         fflush(stderr);
 835         opr_abort();
 836     }
 837 #endif
 838
 839     /* See if polling request. If so, handle right here */
 840     if (timeout != NULL) {
 841         if (timeout->tv_sec == 0 && timeout->tv_usec == 0) {
 842             int code;
 843 #ifdef DEBUG
 844             if (lwp_debug != 0) puts("[Polling SELECT]");
 845 #endif /* DEBUG */
 846 #if     defined(AFS_SGI_ENV) || defined(AFS_SUN5_ENV) || defined(AFS_OSF_ENV) || defined(AFS_AIX32_ENV) || defined(AFS_NT40_ENV)
 847 again:
 848 #endif
 849             code = select(fds, readfds, writefds, exceptfds, timeout);
 850 #if     defined(AFS_SGI_ENV) || defined(AFS_SUN5_ENV) || defined(AFS_OSF_ENV) || defined(AFS_AIX32_ENV)
 851             /*
 852              * For SGI and SVR4 - poll & select can return EAGAIN ...
 853              */
 854             /*
 855              * this is basically for SGI, but I believe stock SVR4 (Solaris?)
 856              * can also get this error return
 857              */
 858             if (code < 0 && errno == EAGAIN)
 859                 goto again;
 860 #endif
 861 #ifdef AFS_NT40_ENV
 862             if (code == SOCKET_ERROR) {
 863                 if (WSAGetLastError() == WSAEINPROGRESS)
 864                     goto again;
 865
 866                 code = -1;
 867             }
 868 #endif
 869             return (code > 1 ? 1 : code);
 870         }
 871     }
 872
 873     /* Construct request block & insert */
 874     request = NewRequest(); /* zeroes fd_set's */
 875     if (readfds && !FDSetEmpty(fds, readfds))
 876         request->readfds = readfds;
 877     if (writefds && !FDSetEmpty(fds, writefds))
 878         request->writefds = writefds;
 879     if (exceptfds && !FDSetEmpty(fds, exceptfds))
 880         request->exceptfds = exceptfds;
 881     request->nfds = fds;
 882
 883     if (timeout == NULL) {
 884         request -> timeout.TotalTime.tv_sec = -1;
 885         request -> timeout.TotalTime.tv_usec = -1;
 886     } else {
 887         request -> timeout.TotalTime = *timeout;
 888         /* check for bad request */
 889         if (timeout->tv_sec < 0 || timeout->tv_usec < 0 || timeout->tv_usec > 999999) {
 890             /* invalid arg */
 891             iomgr_badtv = *timeout;
 892             iomgr_badpid = LWP_ActiveProcess;
 893             /* now fixup request */
 894             if(request->timeout.TotalTime.tv_sec < 0)
 895                 request->timeout.TotalTime.tv_sec = 1;
 896             request->timeout.TotalTime.tv_usec = 100000;
 897         }
 898     }
 899
 900     request -> timeout.BackPointer = (char *) request;
 901
 902     /* Insert my PID in case of IOMGR_Cancel */
 903     request -> pid = LWP_ActiveProcess;
 904     LWP_ActiveProcess -> iomgrRequest = request;
 905
 906 #ifdef DEBUG
 907     request -> timeout.Next = (struct TM_Elem *) 1;
 908     request -> timeout.Prev = (struct TM_Elem *) 1;
 909 #endif /* DEBUG */
 910     TM_Insert(Requests, &request->timeout);
 911
 912     /* Wait for action */
 913     LWP_QWait();
 914
 915     /* Update parameters & return */
 916     result = request -> result;
 917
 918     FreeRequest(request);
 919     return (result > 1 ? 1 : result);
 920 }
 921
 922 int IOMGR_Cancel(PROCESS pid)
 923 {
 924     struct IoRequest *request;
 925
 926     if ((request = pid->iomgrRequest) == 0) return -1;  /* Pid not found */
 927
 928     if (request->readfds)   FD_N_ZERO(request->nfds, request->readfds);
 929     if (request->writefds)  FD_N_ZERO(request->nfds, request->writefds);
 930     if (request->exceptfds) FD_N_ZERO(request->nfds, request->exceptfds);
 931     request->nfds = 0;
 932
 933     request -> result = -2;
 934     TM_Remove(Requests, &request->timeout);
 935 #ifdef DEBUG
 936     request -> timeout.Next = (struct TM_Elem *) 5;
 937     request -> timeout.Prev = (struct TM_Elem *) 5;
 938 #endif /* DEBUG */
 939     LWP_QSignal(request->pid);
 940     pid->iomgrRequest = 0;
 941
 942     return 0;
 943 }
 944
 945 #ifndef AFS_NT40_ENV
 946 /* Cause delivery of signal signo to result in a LWP_SignalProcess of
 947    event. */
 948 int IOMGR_Signal (int signo, char *event)
 949 {
 950     struct sigaction sa;
 951
 952     if (badsig(signo))
 953         return LWP_EBADSIG;
 954     if (event == NULL)
 955         return LWP_EBADEVENT;
 956     sa.sa_handler = SigHandler;
 957     sigfillset(&sa.sa_mask);    /* mask all signals */
 958     sa.sa_flags = 0;
 959     sigsHandled |= mysigmask(signo);
 960     sigEvents[signo] = event;
 961     sigDelivered[signo] = FALSE;
 962     if (sigaction (signo, &sa, &oldActions[signo]) == -1)
 963         return LWP_ESYSTEM;
 964     return LWP_SUCCESS;
 965 }
 966
 967 /* Stop handling occurrences of signo. */
 968 int IOMGR_CancelSignal (int signo)
 969 {
 970     if (badsig(signo) || (sigsHandled & mysigmask(signo)) == 0)
 971         return LWP_EBADSIG;
 972     sigaction (signo, &oldActions[signo], NULL);
 973     sigsHandled &= ~mysigmask(signo);
 974     return LWP_SUCCESS;
 975 }
 976 #endif /* AFS_NT40_ENV */
 977 /* This routine calls select is a fashion that simulates the standard sleep routine */
 978 void IOMGR_Sleep (int seconds)
 979 {
 980     struct timeval timeout;
 981
 982     timeout.tv_sec = seconds;
 983     timeout.tv_usec = 0;
 984     IOMGR_Select(0, 0, 0, 0, &timeout);
 985 }