blob: 8c070e4b76bd8b51015413abdf6d98acb1c28eef [file] [log] [blame]
/*
* 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).
*
*/
#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);
/*
* The fd table and the number of file descriptors
*/
static fdEntry_t *fdTable = NULL;
static int fdCount = 0;
/*
* 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;
/* Check already initialized */
if (fdCount > 0 && fdTable != NULL) {
return;
}
/*
* Allocate table based on the maximum number of
* file descriptors.
*/
if (-1 == getrlimit(RLIMIT_NOFILE, &nbr_files)) {
fprintf(stderr, "library initialization failed - "
"unable to get max # of allocated fds\n");
abort();
}
fdCount = nbr_files.rlim_max;
/*
* We have a conceptual problem here, when the number of files is
* unlimited. As a kind of workaround, we ensure the table is big
* enough for handle even a large number of files. Since SAP itself
* recommends a limit of 32000 files, we just use 64000 as 'infinity'.
*/
if (nbr_files.rlim_max == RLIM_INFINITY) {
fdCount = 64000;
}
fdTable = (fdEntry_t *)calloc(fdCount, sizeof(fdEntry_t));
if (fdTable == NULL) {
fprintf(stderr, "library initialization failed - "
"unable to allocate file descriptor table - out of memory");
abort();
}
{
int i;
for (i=0; i < fdCount; i++) {
pthread_mutex_init(&fdTable[i].lock, NULL);
}
}
/*
* 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 or NULL is fd out
* of range.
*/
static inline fdEntry_t *getFdEntry(int fd)
{
if (fd < 0 || fd >= fdCount) {
return NULL;
}
return &fdTable[fd];
}
/*
* 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_NonBlockingRead(int s, void* buf, size_t len) {
BLOCKING_IO_RETURN_INT(s, recv(s, buf, len, MSG_NONBLOCK));
}
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;
}
#ifndef USE_SELECT
int NET_Poll(struct pollfd *ufds, unsigned int nfds, int timeout) {
BLOCKING_IO_RETURN_INT( ufds[0].fd, poll(ufds, nfds, timeout) );
}
#else
int NET_Select(int s, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, struct timeval *timeout) {
BLOCKING_IO_RETURN_INT( s-1,
select(s, readfds, writefds, exceptfds, timeout) );
}
#endif
/*
* Wrapper for poll(s, timeout).
* Auto restarts with adjusted timeout if interrupted by
* signal other than our wakeup signal.
*/
int NET_Timeout0(int s, long timeout, long currentTime) {
long prevtime = currentTime, newtime;
struct timeval t;
fdEntry_t *fdEntry = getFdEntry(s);
/*
* Check that fd hasn't been closed.
*/
if (fdEntry == NULL) {
errno = EBADF;
return -1;
}
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;
}
}
}