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luasocket/src/usocket.c
Sam Roberts f63d616bc0 Use poll by default for socket.connect(), instead of select(). 
Connect timeouts are implemented by waiting on the new socket
descriptor. When select() is used for this, it imposes an arbitrary
limit on the number of connections that can be made, usually 1024-3.
Using poll() removes this limit on the number of simultaneous TCP
connections can be made using luasocket. The previous default
implementation using select() is available by defining SOCKET_SELECT.
Note that using socket.select() always uses select(), so it isn't
possible to wait on an arbitrary number of connections at once.
2012-04-11 13:45:59 -07:00

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/*=========================================================================*\
* Socket compatibilization module for Unix
* LuaSocket toolkit
*
* The code is now interrupt-safe.
* The penalty of calling select to avoid busy-wait is only paid when
* the I/O call fail in the first place.
*
* RCS ID: $Id$
\*=========================================================================*/
#include <string.h>
#include <signal.h>
#include "socket.h"
/*-------------------------------------------------------------------------*\
* Wait for readable/writable/connected socket with timeout
\*-------------------------------------------------------------------------*/
#ifndef SOCKET_SELECT
#include <sys/poll.h>
#define WAITFD_R POLLIN
#define WAITFD_W POLLOUT
#define WAITFD_C (POLLIN|POLLOUT)
int socket_waitfd(p_socket ps, int sw, p_timeout tm) {
int ret;
struct pollfd pfd;
pfd.fd = *ps;
pfd.events = sw;
pfd.revents = 0;
if (timeout_iszero(tm)) return IO_TIMEOUT; /* optimize timeout == 0 case */
do {
int t = (int)(timeout_getretry(tm)*1e3);
ret = poll(&pfd, 1, t >= 0? t: -1);
} while (ret == -1 && errno == EINTR);
if (ret == -1) return errno;
if (ret == 0) return IO_TIMEOUT;
if (sw == WAITFD_C && (pfd.revents & (POLLIN|POLLERR))) return IO_CLOSED;
return IO_DONE;
}
#else
#define WAITFD_R 1
#define WAITFD_W 2
#define WAITFD_C (WAITFD_R|WAITFD_W)
int socket_waitfd(p_socket ps, int sw, p_timeout tm) {
int ret;
fd_set rfds, wfds, *rp, *wp;
struct timeval tv, *tp;
double t;
if (timeout_iszero(tm)) return IO_TIMEOUT; /* optimize timeout == 0 case */
do {
/* must set bits within loop, because select may have modifed them */
rp = wp = NULL;
if (sw & WAITFD_R) { FD_ZERO(&rfds); FD_SET(*ps, &rfds); rp = &rfds; }
if (sw & WAITFD_W) { FD_ZERO(&wfds); FD_SET(*ps, &wfds); wp = &wfds; }
t = timeout_getretry(tm);
tp = NULL;
if (t >= 0.0) {
tv.tv_sec = (int)t;
tv.tv_usec = (int)((t-tv.tv_sec)*1.0e6);
tp = &tv;
}
ret = select(*ps+1, rp, wp, NULL, tp);
} while (ret == -1 && errno == EINTR);
if (ret == -1) return errno;
if (ret == 0) return IO_TIMEOUT;
if (sw == WAITFD_C && FD_ISSET(*ps, &rfds)) return IO_CLOSED;
return IO_DONE;
}
#endif
/*-------------------------------------------------------------------------*\
* Initializes module
\*-------------------------------------------------------------------------*/
int socket_open(void) {
/* instals a handler to ignore sigpipe or it will crash us */
signal(SIGPIPE, SIG_IGN);
return 1;
}
/*-------------------------------------------------------------------------*\
* Close module
\*-------------------------------------------------------------------------*/
int socket_close(void) {
return 1;
}
/*-------------------------------------------------------------------------*\
* Close and inutilize socket
\*-------------------------------------------------------------------------*/
void socket_destroy(p_socket ps) {
if (*ps != SOCKET_INVALID) {
socket_setblocking(ps);
close(*ps);
*ps = SOCKET_INVALID;
}
}
/*-------------------------------------------------------------------------*\
* Select with timeout control
\*-------------------------------------------------------------------------*/
int socket_select(t_socket n, fd_set *rfds, fd_set *wfds, fd_set *efds,
p_timeout tm) {
int ret;
do {
struct timeval tv;
double t = timeout_getretry(tm);
tv.tv_sec = (int) t;
tv.tv_usec = (int) ((t - tv.tv_sec) * 1.0e6);
/* timeout = 0 means no wait */
ret = select(n, rfds, wfds, efds, t >= 0.0 ? &tv: NULL);
} while (ret < 0 && errno == EINTR);
return ret;
}
/*-------------------------------------------------------------------------*\
* Creates and sets up a socket
\*-------------------------------------------------------------------------*/
int socket_create(p_socket ps, int domain, int type, int protocol) {
*ps = socket(domain, type, protocol);
if (*ps != SOCKET_INVALID) return IO_DONE;
else return errno;
}
/*-------------------------------------------------------------------------*\
* Binds or returns error message
\*-------------------------------------------------------------------------*/
int socket_bind(p_socket ps, SA *addr, socklen_t len) {
int err = IO_DONE;
socket_setblocking(ps);
if (bind(*ps, addr, len) < 0) err = errno;
socket_setnonblocking(ps);
return err;
}
/*-------------------------------------------------------------------------*\
*
\*-------------------------------------------------------------------------*/
int socket_listen(p_socket ps, int backlog) {
int err = IO_DONE;
socket_setblocking(ps);
if (listen(*ps, backlog)) err = errno;
socket_setnonblocking(ps);
return err;
}
/*-------------------------------------------------------------------------*\
*
\*-------------------------------------------------------------------------*/
void socket_shutdown(p_socket ps, int how) {
socket_setblocking(ps);
shutdown(*ps, how);
socket_setnonblocking(ps);
}
/*-------------------------------------------------------------------------*\
* Connects or returns error message
\*-------------------------------------------------------------------------*/
int socket_connect(p_socket ps, SA *addr, socklen_t len, p_timeout tm) {
int err;
/* avoid calling on closed sockets */
if (*ps == SOCKET_INVALID) return IO_CLOSED;
/* call connect until done or failed without being interrupted */
do if (connect(*ps, addr, len) == 0) return IO_DONE;
while ((err = errno) == EINTR);
/* if connection failed immediately, return error code */
if (err != EINPROGRESS && err != EAGAIN) return err;
/* zero timeout case optimization */
if (timeout_iszero(tm)) return IO_TIMEOUT;
/* wait until we have the result of the connection attempt or timeout */
err = socket_waitfd(ps, WAITFD_C, tm);
if (err == IO_CLOSED) {
if (recv(*ps, (char *) &err, 0, 0) == 0) return IO_DONE;
else return errno;
} else return err;
}
/*-------------------------------------------------------------------------*\
* Accept with timeout
\*-------------------------------------------------------------------------*/
int socket_accept(p_socket ps, p_socket pa, SA *addr, socklen_t *len, p_timeout tm) {
SA daddr;
socklen_t dlen = sizeof(daddr);
if (*ps == SOCKET_INVALID) return IO_CLOSED;
if (!addr) addr = &daddr;
if (!len) len = &dlen;
for ( ;; ) {
int err;
if ((*pa = accept(*ps, addr, len)) != SOCKET_INVALID) return IO_DONE;
err = errno;
if (err == EINTR) continue;
if (err != EAGAIN && err != ECONNABORTED) return err;
if ((err = socket_waitfd(ps, WAITFD_R, tm)) != IO_DONE) return err;
}
/* can't reach here */
return IO_UNKNOWN;
}
/*-------------------------------------------------------------------------*\
* Send with timeout
\*-------------------------------------------------------------------------*/
int socket_send(p_socket ps, const char *data, size_t count,
size_t *sent, p_timeout tm)
{
int err;
*sent = 0;
/* avoid making system calls on closed sockets */
if (*ps == SOCKET_INVALID) return IO_CLOSED;
/* loop until we send something or we give up on error */
for ( ;; ) {
long put = (long) send(*ps, data, count, 0);
/* if we sent anything, we are done */
if (put >= 0) {
*sent = put;
return IO_DONE;
}
err = errno;
/* EPIPE means the connection was closed */
if (err == EPIPE) return IO_CLOSED;
/* we call was interrupted, just try again */
if (err == EINTR) continue;
/* if failed fatal reason, report error */
if (err != EAGAIN) return err;
/* wait until we can send something or we timeout */
if ((err = socket_waitfd(ps, WAITFD_W, tm)) != IO_DONE) return err;
}
/* can't reach here */
return IO_UNKNOWN;
}
/*-------------------------------------------------------------------------*\
* Sendto with timeout
\*-------------------------------------------------------------------------*/
int socket_sendto(p_socket ps, const char *data, size_t count, size_t *sent,
SA *addr, socklen_t len, p_timeout tm)
{
int err;
*sent = 0;
if (*ps == SOCKET_INVALID) return IO_CLOSED;
for ( ;; ) {
long put = (long) sendto(*ps, data, count, 0, addr, len);
if (put >= 0) {
*sent = put;
return IO_DONE;
}
err = errno;
if (err == EPIPE) return IO_CLOSED;
if (err == EINTR) continue;
if (err != EAGAIN) return err;
if ((err = socket_waitfd(ps, WAITFD_W, tm)) != IO_DONE) return err;
}
return IO_UNKNOWN;
}
/*-------------------------------------------------------------------------*\
* Receive with timeout
\*-------------------------------------------------------------------------*/
int socket_recv(p_socket ps, char *data, size_t count, size_t *got, p_timeout tm) {
int err;
*got = 0;
if (*ps == SOCKET_INVALID) return IO_CLOSED;
for ( ;; ) {
long taken = (long) recv(*ps, data, count, 0);
if (taken > 0) {
*got = taken;
return IO_DONE;
}
err = errno;
if (taken == 0) return IO_CLOSED;
if (err == EINTR) continue;
if (err != EAGAIN) return err;
if ((err = socket_waitfd(ps, WAITFD_R, tm)) != IO_DONE) return err;
}
return IO_UNKNOWN;
}
/*-------------------------------------------------------------------------*\
* Recvfrom with timeout
\*-------------------------------------------------------------------------*/
int socket_recvfrom(p_socket ps, char *data, size_t count, size_t *got,
SA *addr, socklen_t *len, p_timeout tm) {
int err;
*got = 0;
if (*ps == SOCKET_INVALID) return IO_CLOSED;
for ( ;; ) {
long taken = (long) recvfrom(*ps, data, count, 0, addr, len);
if (taken > 0) {
*got = taken;
return IO_DONE;
}
err = errno;
if (taken == 0) return IO_CLOSED;
if (err == EINTR) continue;
if (err != EAGAIN) return err;
if ((err = socket_waitfd(ps, WAITFD_R, tm)) != IO_DONE) return err;
}
return IO_UNKNOWN;
}
/*-------------------------------------------------------------------------*\
* Put socket into blocking mode
\*-------------------------------------------------------------------------*/
void socket_setblocking(p_socket ps) {
int flags = fcntl(*ps, F_GETFL, 0);
flags &= (~(O_NONBLOCK));
fcntl(*ps, F_SETFL, flags);
}
/*-------------------------------------------------------------------------*\
* Put socket into non-blocking mode
\*-------------------------------------------------------------------------*/
void socket_setnonblocking(p_socket ps) {
int flags = fcntl(*ps, F_GETFL, 0);
flags |= O_NONBLOCK;
fcntl(*ps, F_SETFL, flags);
}
/*-------------------------------------------------------------------------*\
* DNS helpers
\*-------------------------------------------------------------------------*/
int socket_gethostbyaddr(const char *addr, socklen_t len, struct hostent **hp) {
*hp = gethostbyaddr(addr, len, AF_INET);
if (*hp) return IO_DONE;
else if (h_errno) return h_errno;
else if (errno) return errno;
else return IO_UNKNOWN;
}
int socket_gethostbyname(const char *addr, struct hostent **hp) {
*hp = gethostbyname(addr);
if (*hp) return IO_DONE;
else if (h_errno) return h_errno;
else if (errno) return errno;
else return IO_UNKNOWN;
}
/*-------------------------------------------------------------------------*\
* Error translation functions
* Make sure important error messages are standard
\*-------------------------------------------------------------------------*/
const char *socket_hoststrerror(int err) {
if (err <= 0) return io_strerror(err);
switch (err) {
case HOST_NOT_FOUND: return "host not found";
default: return hstrerror(err);
}
}
const char *socket_strerror(int err) {
if (err <= 0) return io_strerror(err);
switch (err) {
case EADDRINUSE: return "address already in use";
case EISCONN: return "already connected";
case EACCES: return "permission denied";
case ECONNREFUSED: return "connection refused";
case ECONNABORTED: return "closed";
case ECONNRESET: return "closed";
case ETIMEDOUT: return "timedout";
default: return strerror(errno);
}
}
const char *socket_ioerror(p_socket ps, int err) {
(void) ps;
return socket_strerror(err);
}
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