| /* |
| * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved. |
| * Copyright (c) 2016, SAP SE and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * This file contains implementations of NET_... functions. The NET_.. functions are |
| * wrappers for common file- and socket functions plus provisions for non-blocking IO. |
| * |
| * (basically, the layers remember all file descriptors waiting for a particular fd; |
| * all threads waiting on a certain fd can be woken up by sending them a signal; this |
| * is done e.g. when the fd is closed.) |
| * |
| * This was originally copied from the linux_close.c implementation. |
| * |
| * Side Note: This coding needs initialization. Under Linux this is done |
| * automatically via __attribute((constructor)), on AIX this is done manually |
| * (see aix_close_init). |
| * |
| */ |
| |
| /* |
| AIX needs a workaround for I/O cancellation, see: |
| http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/close.htm |
| ... |
| The close subroutine is blocked until all subroutines which use the file |
| descriptor return to usr space. For example, when a thread is calling close |
| and another thread is calling select with the same file descriptor, the |
| close subroutine does not return until the select call returns. |
| ... |
| */ |
| |
| #include <assert.h> |
| #include <limits.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <signal.h> |
| #include <pthread.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <sys/time.h> |
| #include <sys/resource.h> |
| #include <sys/uio.h> |
| #include <unistd.h> |
| #include <errno.h> |
| #include <sys/poll.h> |
| |
| /* |
| * Stack allocated by thread when doing blocking operation |
| */ |
| typedef struct threadEntry { |
| pthread_t thr; /* this thread */ |
| struct threadEntry *next; /* next thread */ |
| int intr; /* interrupted */ |
| } threadEntry_t; |
| |
| /* |
| * Heap allocated during initialized - one entry per fd |
| */ |
| typedef struct { |
| pthread_mutex_t lock; /* fd lock */ |
| threadEntry_t *threads; /* threads blocked on fd */ |
| } fdEntry_t; |
| |
| /* |
| * Signal to unblock thread |
| */ |
| static int sigWakeup = (SIGRTMAX - 1); |
| |
| /* |
| * fdTable holds one entry per file descriptor, up to a certain |
| * maximum. |
| * Theoretically, the number of possible file descriptors can get |
| * large, though usually it does not. Entries for small value file |
| * descriptors are kept in a simple table, which covers most scenarios. |
| * Entries for large value file descriptors are kept in an overflow |
| * table, which is organized as a sparse two dimensional array whose |
| * slabs are allocated on demand. This covers all corner cases while |
| * keeping memory consumption reasonable. |
| */ |
| |
| /* Base table for low value file descriptors */ |
| static fdEntry_t* fdTable = NULL; |
| /* Maximum size of base table (in number of entries). */ |
| static const int fdTableMaxSize = 0x1000; /* 4K */ |
| /* Actual size of base table (in number of entries) */ |
| static int fdTableLen = 0; |
| /* Max. theoretical number of file descriptors on system. */ |
| static int fdLimit = 0; |
| |
| /* Overflow table, should base table not be large enough. Organized as |
| * an array of n slabs, each holding 64k entries. |
| */ |
| static fdEntry_t** fdOverflowTable = NULL; |
| /* Number of slabs in the overflow table */ |
| static int fdOverflowTableLen = 0; |
| /* Number of entries in one slab */ |
| static const int fdOverflowTableSlabSize = 0x10000; /* 64k */ |
| pthread_mutex_t fdOverflowTableLock = PTHREAD_MUTEX_INITIALIZER; |
| |
| /* |
| * Null signal handler |
| */ |
| static void sig_wakeup(int sig) { |
| } |
| |
| /* |
| * Initialization routine (executed when library is loaded) |
| * Allocate fd tables and sets up signal handler. |
| * |
| * On AIX we don't have __attribute((constructor)) so we need to initialize |
| * manually (from JNI_OnLoad() in 'src/share/native/java/net/net_util.c') |
| */ |
| void aix_close_init() { |
| struct rlimit nbr_files; |
| sigset_t sigset; |
| struct sigaction sa; |
| int i = 0; |
| |
| /* Determine the maximum number of possible file descriptors. */ |
| if (-1 == getrlimit(RLIMIT_NOFILE, &nbr_files)) { |
| fprintf(stderr, "library initialization failed - " |
| "unable to get max # of allocated fds\n"); |
| abort(); |
| } |
| if (nbr_files.rlim_max != RLIM_INFINITY) { |
| fdLimit = nbr_files.rlim_max; |
| } else { |
| /* We just do not know. */ |
| fdLimit = INT_MAX; |
| } |
| |
| /* Allocate table for low value file descriptors. */ |
| fdTableLen = fdLimit < fdTableMaxSize ? fdLimit : fdTableMaxSize; |
| fdTable = (fdEntry_t*) calloc(fdTableLen, sizeof(fdEntry_t)); |
| if (fdTable == NULL) { |
| fprintf(stderr, "library initialization failed - " |
| "unable to allocate file descriptor table - out of memory"); |
| abort(); |
| } else { |
| for (i = 0; i < fdTableLen; i ++) { |
| pthread_mutex_init(&fdTable[i].lock, NULL); |
| } |
| } |
| |
| /* Allocate overflow table, if needed */ |
| if (fdLimit > fdTableMaxSize) { |
| fdOverflowTableLen = ((fdLimit - fdTableMaxSize) / fdOverflowTableSlabSize) + 1; |
| fdOverflowTable = (fdEntry_t**) calloc(fdOverflowTableLen, sizeof(fdEntry_t*)); |
| if (fdOverflowTable == NULL) { |
| fprintf(stderr, "library initialization failed - " |
| "unable to allocate file descriptor overflow table - out of memory"); |
| abort(); |
| } |
| } |
| |
| /* |
| * Setup the signal handler |
| */ |
| sa.sa_handler = sig_wakeup; |
| sa.sa_flags = 0; |
| sigemptyset(&sa.sa_mask); |
| sigaction(sigWakeup, &sa, NULL); |
| |
| sigemptyset(&sigset); |
| sigaddset(&sigset, sigWakeup); |
| sigprocmask(SIG_UNBLOCK, &sigset, NULL); |
| } |
| |
| /* |
| * Return the fd table for this fd. |
| */ |
| static inline fdEntry_t *getFdEntry(int fd) |
| { |
| fdEntry_t* result = NULL; |
| |
| if (fd < 0) { |
| return NULL; |
| } |
| |
| /* This should not happen. If it does, our assumption about |
| * max. fd value was wrong. */ |
| assert(fd < fdLimit); |
| |
| if (fd < fdTableMaxSize) { |
| /* fd is in base table. */ |
| assert(fd < fdTableLen); |
| result = &fdTable[fd]; |
| } else { |
| /* fd is in overflow table. */ |
| const int indexInOverflowTable = fd - fdTableMaxSize; |
| const int rootindex = indexInOverflowTable / fdOverflowTableSlabSize; |
| const int slabindex = indexInOverflowTable % fdOverflowTableSlabSize; |
| fdEntry_t* slab = NULL; |
| assert(rootindex < fdOverflowTableLen); |
| assert(slabindex < fdOverflowTableSlabSize); |
| pthread_mutex_lock(&fdOverflowTableLock); |
| /* Allocate new slab in overflow table if needed */ |
| if (fdOverflowTable[rootindex] == NULL) { |
| fdEntry_t* const newSlab = |
| (fdEntry_t*)calloc(fdOverflowTableSlabSize, sizeof(fdEntry_t)); |
| if (newSlab == NULL) { |
| fprintf(stderr, "Unable to allocate file descriptor overflow" |
| " table slab - out of memory"); |
| pthread_mutex_unlock(&fdOverflowTableLock); |
| abort(); |
| } else { |
| int i; |
| for (i = 0; i < fdOverflowTableSlabSize; i ++) { |
| pthread_mutex_init(&newSlab[i].lock, NULL); |
| } |
| fdOverflowTable[rootindex] = newSlab; |
| } |
| } |
| pthread_mutex_unlock(&fdOverflowTableLock); |
| slab = fdOverflowTable[rootindex]; |
| result = &slab[slabindex]; |
| } |
| |
| return result; |
| |
| } |
| |
| |
| /* |
| * Start a blocking operation :- |
| * Insert thread onto thread list for the fd. |
| */ |
| static inline void startOp(fdEntry_t *fdEntry, threadEntry_t *self) |
| { |
| self->thr = pthread_self(); |
| self->intr = 0; |
| |
| pthread_mutex_lock(&(fdEntry->lock)); |
| { |
| self->next = fdEntry->threads; |
| fdEntry->threads = self; |
| } |
| pthread_mutex_unlock(&(fdEntry->lock)); |
| } |
| |
| /* |
| * End a blocking operation :- |
| * Remove thread from thread list for the fd |
| * If fd has been interrupted then set errno to EBADF |
| */ |
| static inline void endOp |
| (fdEntry_t *fdEntry, threadEntry_t *self) |
| { |
| int orig_errno = errno; |
| pthread_mutex_lock(&(fdEntry->lock)); |
| { |
| threadEntry_t *curr, *prev=NULL; |
| curr = fdEntry->threads; |
| while (curr != NULL) { |
| if (curr == self) { |
| if (curr->intr) { |
| orig_errno = EBADF; |
| } |
| if (prev == NULL) { |
| fdEntry->threads = curr->next; |
| } else { |
| prev->next = curr->next; |
| } |
| break; |
| } |
| prev = curr; |
| curr = curr->next; |
| } |
| } |
| pthread_mutex_unlock(&(fdEntry->lock)); |
| errno = orig_errno; |
| } |
| |
| /* |
| * Close or dup2 a file descriptor ensuring that all threads blocked on |
| * the file descriptor are notified via a wakeup signal. |
| * |
| * fd1 < 0 => close(fd2) |
| * fd1 >= 0 => dup2(fd1, fd2) |
| * |
| * Returns -1 with errno set if operation fails. |
| */ |
| static int closefd(int fd1, int fd2) { |
| int rv, orig_errno; |
| fdEntry_t *fdEntry = getFdEntry(fd2); |
| if (fdEntry == NULL) { |
| errno = EBADF; |
| return -1; |
| } |
| |
| /* |
| * Lock the fd to hold-off additional I/O on this fd. |
| */ |
| pthread_mutex_lock(&(fdEntry->lock)); |
| |
| { |
| /* On fast machines we see that we enter dup2 before the |
| * accepting thread had a chance to get and process the signal. |
| * So in case we woke a thread up, give it some time to cope. |
| * Also see https://bugs.openjdk.java.net/browse/JDK-8006395 */ |
| int num_woken = 0; |
| |
| /* |
| * Send a wakeup signal to all threads blocked on this |
| * file descriptor. |
| */ |
| threadEntry_t *curr = fdEntry->threads; |
| while (curr != NULL) { |
| curr->intr = 1; |
| pthread_kill( curr->thr, sigWakeup ); |
| num_woken ++; |
| curr = curr->next; |
| } |
| |
| if (num_woken > 0) { |
| usleep(num_woken * 50); |
| } |
| |
| /* |
| * And close/dup the file descriptor |
| * (restart if interrupted by signal) |
| */ |
| do { |
| if (fd1 < 0) { |
| rv = close(fd2); |
| } else { |
| rv = dup2(fd1, fd2); |
| } |
| } while (rv == -1 && errno == EINTR); |
| } |
| |
| /* |
| * Unlock without destroying errno |
| */ |
| orig_errno = errno; |
| pthread_mutex_unlock(&(fdEntry->lock)); |
| errno = orig_errno; |
| |
| return rv; |
| } |
| |
| /* |
| * Wrapper for dup2 - same semantics as dup2 system call except |
| * that any threads blocked in an I/O system call on fd2 will be |
| * preempted and return -1/EBADF; |
| */ |
| int NET_Dup2(int fd, int fd2) { |
| if (fd < 0) { |
| errno = EBADF; |
| return -1; |
| } |
| return closefd(fd, fd2); |
| } |
| |
| /* |
| * Wrapper for close - same semantics as close system call |
| * except that any threads blocked in an I/O on fd will be |
| * preempted and the I/O system call will return -1/EBADF. |
| */ |
| int NET_SocketClose(int fd) { |
| return closefd(-1, fd); |
| } |
| |
| /************** Basic I/O operations here ***************/ |
| |
| /* |
| * Macro to perform a blocking IO operation. Restarts |
| * automatically if interrupted by signal (other than |
| * our wakeup signal) |
| */ |
| #define BLOCKING_IO_RETURN_INT(FD, FUNC) { \ |
| int ret; \ |
| threadEntry_t self; \ |
| fdEntry_t *fdEntry = getFdEntry(FD); \ |
| if (fdEntry == NULL) { \ |
| errno = EBADF; \ |
| return -1; \ |
| } \ |
| do { \ |
| startOp(fdEntry, &self); \ |
| ret = FUNC; \ |
| endOp(fdEntry, &self); \ |
| } while (ret == -1 && errno == EINTR); \ |
| return ret; \ |
| } |
| |
| int NET_Read(int s, void* buf, size_t len) { |
| BLOCKING_IO_RETURN_INT( s, recv(s, buf, len, 0) ); |
| } |
| |
| int NET_ReadV(int s, const struct iovec * vector, int count) { |
| BLOCKING_IO_RETURN_INT( s, readv(s, vector, count) ); |
| } |
| |
| int NET_RecvFrom(int s, void *buf, int len, unsigned int flags, |
| struct sockaddr *from, int *fromlen) { |
| socklen_t socklen = *fromlen; |
| BLOCKING_IO_RETURN_INT( s, recvfrom(s, buf, len, flags, from, &socklen) ); |
| *fromlen = socklen; |
| } |
| |
| int NET_Send(int s, void *msg, int len, unsigned int flags) { |
| BLOCKING_IO_RETURN_INT( s, send(s, msg, len, flags) ); |
| } |
| |
| int NET_WriteV(int s, const struct iovec * vector, int count) { |
| BLOCKING_IO_RETURN_INT( s, writev(s, vector, count) ); |
| } |
| |
| int NET_SendTo(int s, const void *msg, int len, unsigned int |
| flags, const struct sockaddr *to, int tolen) { |
| BLOCKING_IO_RETURN_INT( s, sendto(s, msg, len, flags, to, tolen) ); |
| } |
| |
| int NET_Accept(int s, struct sockaddr *addr, int *addrlen) { |
| socklen_t socklen = *addrlen; |
| BLOCKING_IO_RETURN_INT( s, accept(s, addr, &socklen) ); |
| *addrlen = socklen; |
| } |
| |
| int NET_Connect(int s, struct sockaddr *addr, int addrlen) { |
| int crc = -1, prc = -1; |
| threadEntry_t self; |
| fdEntry_t* fdEntry = getFdEntry(s); |
| |
| if (fdEntry == NULL) { |
| errno = EBADF; |
| return -1; |
| } |
| |
| /* On AIX, when the system call connect() is interrupted, the connection |
| * is not aborted and it will be established asynchronously by the kernel. |
| * Hence, no need to restart connect() when EINTR is received |
| */ |
| startOp(fdEntry, &self); |
| crc = connect(s, addr, addrlen); |
| endOp(fdEntry, &self); |
| |
| if (crc == -1 && errno == EINTR) { |
| struct pollfd s_pollfd; |
| int sockopt_arg = 0; |
| socklen_t len; |
| |
| s_pollfd.fd = s; |
| s_pollfd.events = POLLOUT | POLLERR; |
| |
| /* poll the file descriptor */ |
| do { |
| startOp(fdEntry, &self); |
| prc = poll(&s_pollfd, 1, -1); |
| endOp(fdEntry, &self); |
| } while (prc == -1 && errno == EINTR); |
| |
| if (prc < 0) |
| return prc; |
| |
| len = sizeof(sockopt_arg); |
| |
| /* Check whether the connection has been established */ |
| if (getsockopt(s, SOL_SOCKET, SO_ERROR, &sockopt_arg, &len) == -1) |
| return -1; |
| |
| if (sockopt_arg != 0 ) { |
| errno = sockopt_arg; |
| return -1; |
| } |
| } else { |
| return crc; |
| } |
| |
| /* At this point, fd is connected. Set successful return code */ |
| return 0; |
| } |
| |
| int NET_Poll(struct pollfd *ufds, unsigned int nfds, int timeout) { |
| BLOCKING_IO_RETURN_INT( ufds[0].fd, poll(ufds, nfds, timeout) ); |
| } |
| |
| /* |
| * Wrapper for poll(s, timeout). |
| * Auto restarts with adjusted timeout if interrupted by |
| * signal other than our wakeup signal. |
| */ |
| int NET_Timeout(int s, long timeout) { |
| long prevtime = 0, newtime; |
| struct timeval t; |
| fdEntry_t *fdEntry = getFdEntry(s); |
| |
| /* |
| * Check that fd hasn't been closed. |
| */ |
| if (fdEntry == NULL) { |
| errno = EBADF; |
| return -1; |
| } |
| |
| /* |
| * Pick up current time as may need to adjust timeout |
| */ |
| if (timeout > 0) { |
| gettimeofday(&t, NULL); |
| prevtime = t.tv_sec * 1000 + t.tv_usec / 1000; |
| } |
| |
| for(;;) { |
| struct pollfd pfd; |
| int rv; |
| threadEntry_t self; |
| |
| /* |
| * Poll the fd. If interrupted by our wakeup signal |
| * errno will be set to EBADF. |
| */ |
| pfd.fd = s; |
| pfd.events = POLLIN | POLLERR; |
| |
| startOp(fdEntry, &self); |
| rv = poll(&pfd, 1, timeout); |
| endOp(fdEntry, &self); |
| |
| /* |
| * If interrupted then adjust timeout. If timeout |
| * has expired return 0 (indicating timeout expired). |
| */ |
| if (rv < 0 && errno == EINTR) { |
| if (timeout > 0) { |
| gettimeofday(&t, NULL); |
| newtime = t.tv_sec * 1000 + t.tv_usec / 1000; |
| timeout -= newtime - prevtime; |
| if (timeout <= 0) { |
| return 0; |
| } |
| prevtime = newtime; |
| } |
| } else { |
| return rv; |
| } |
| |
| } |
| } |