/*
* Wait for read or write events on a set of file descriptors. It uses poll()
* when a fine poll() is available, in order to avoid limits with FD_SETSIZE,
* otherwise select() is used. An error is returned if select() is being used
* and a file descriptor is too large for FD_SETSIZE.
*
* A negative timeout value makes this function wait indefinitely,
* unles no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
* When compiled with CURL_ACKNOWLEDGE_EINTR defined, EINTR condition
* is honored and function might exit early without awaiting timeout,
* otherwise EINTR will be ignored.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* [bitmask] = action as described below
*
* CURL_CSELECT_IN - first socket is readable
* CURL_CSELECT_IN2 - second socket is readable
* CURL_CSELECT_OUT - write socket is writable
* CURL_CSELECT_ERR - an error condition occurred
*/
int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
curl_socket_t readfd1,
curl_socket_t writefd, /* socket to write to */
long timeout_ms) /* milliseconds to wait */
{
#ifdef HAVE_POLL_FINE
struct pollfd pfd[3];
int num;
#else
struct timeval pending_tv;
struct timeval *ptimeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
struct timeval initial_tv = {0,0};
int pending_ms = 0;
int error;
int r;
int ret;
if((readfd0 == CURL_SOCKET_BAD) && (readfd1 == CURL_SOCKET_BAD) &&
(writefd == CURL_SOCKET_BAD)) {
/* no sockets, just wait */
r = Curl_wait_ms((int)timeout_ms);
return r;
}
/* Avoid initial timestamp, avoid curlx_tvnow() call, when elapsed
time in this function does not need to be measured. This happens
when function is called with a zero timeout or a negative timeout
value indicating a blocking call should be performed. */
if(timeout_ms > 0) {
pending_ms = (int)timeout_ms;
initial_tv = curlx_tvnow();
}
#ifdef HAVE_POLL_FINE
num = 0;
if(readfd0 != CURL_SOCKET_BAD) {
pfd[num].fd = readfd0;
pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
pfd[num].revents = 0;
num++;
}
if(readfd1 != CURL_SOCKET_BAD) {
pfd[num].fd = readfd1;
pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
pfd[num].revents = 0;
num++;
}
if(writefd != CURL_SOCKET_BAD) {
pfd[num].fd = writefd;
pfd[num].events = POLLWRNORM|POLLOUT;
pfd[num].revents = 0;
num++;
}
do {
if(timeout_ms < 0)
pending_ms = -1;
else if(!timeout_ms)
pending_ms = 0;
r = poll(pfd, num, pending_ms);
if(r != -1)
break;
error = SOCKERRNO;
if(error && error_not_EINTR)
break;
if(timeout_ms > 0) {
pending_ms = (int)(timeout_ms - elapsed_ms);
if(pending_ms <= 0) {
r = 0; /* Simulate a "call timed out" case */
break;
}
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
ret = 0;
num = 0;
if(readfd0 != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
ret |= CURL_CSELECT_IN;
if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
num++;
}
if(readfd1 != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
ret |= CURL_CSELECT_IN2;
if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
num++;
}
if(writefd != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLWRNORM|POLLOUT))
ret |= CURL_CSELECT_OUT;
if(pfd[num].revents & (POLLERR|POLLHUP|POLLNVAL))
ret |= CURL_CSELECT_ERR;
}
return ret;
#else /* HAVE_POLL_FINE */
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
FD_ZERO(&fds_read);
if(readfd0 != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd0);
FD_SET(readfd0, &fds_read);
FD_SET(readfd0, &fds_err);
maxfd = readfd0;
}
if(readfd1 != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd1);
FD_SET(readfd1, &fds_read);
FD_SET(readfd1, &fds_err);
if(readfd1 > maxfd)
maxfd = readfd1;
}
FD_ZERO(&fds_write);
if(writefd != CURL_SOCKET_BAD) {
VERIFY_SOCK(writefd);
FD_SET(writefd, &fds_write);
FD_SET(writefd, &fds_err);
if(writefd > maxfd)
maxfd = writefd;
}
ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
do {
if(timeout_ms > 0) {
pending_tv.tv_sec = pending_ms / 1000;
pending_tv.tv_usec = (pending_ms % 1000) * 1000;
}
else if(!timeout_ms) {
pending_tv.tv_sec = 0;
pending_tv.tv_usec = 0;
}
r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
if(r != -1)
break;
error = SOCKERRNO;
if(error && error_not_EINTR)
break;
if(timeout_ms > 0) {
pending_ms = timeout_ms - elapsed_ms;
if(pending_ms <= 0) {
r = 0; /* Simulate a "call timed out" case */
break;
}
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
ret = 0;
if(readfd0 != CURL_SOCKET_BAD) {
if(FD_ISSET(readfd0, &fds_read))
ret |= CURL_CSELECT_IN;
if(FD_ISSET(readfd0, &fds_err))
ret |= CURL_CSELECT_ERR;
}
if(readfd1 != CURL_SOCKET_BAD) {
if(FD_ISSET(readfd1, &fds_read))
ret |= CURL_CSELECT_IN2;
if(FD_ISSET(readfd1, &fds_err))
ret |= CURL_CSELECT_ERR;
}
if(writefd != CURL_SOCKET_BAD) {
if(FD_ISSET(writefd, &fds_write))
ret |= CURL_CSELECT_OUT;
if(FD_ISSET(writefd, &fds_err))
ret |= CURL_CSELECT_ERR;
}
return ret;
#endif /* HAVE_POLL_FINE */
}
/*
* This is a wrapper around poll(). If poll() does not exist, then
* select() is used instead. An error is returned if select() is
* being used and a file descriptor is too large for FD_SETSIZE.
* A negative timeout value makes this function wait indefinitely,
* unles no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
* When compiled with CURL_ACKNOWLEDGE_EINTR defined, EINTR condition
* is honored and function might exit early without awaiting timeout,
* otherwise EINTR will be ignored.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* N = number of structures with non zero revent fields
*/
int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
{
#ifndef HAVE_POLL_FINE
struct timeval pending_tv;
struct timeval *ptimeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
struct timeval initial_tv = {0,0};
bool fds_none = TRUE;
unsigned int i;
int pending_ms = 0;
int error;
int r;
if(ufds) {
for(i = 0; i < nfds; i++) {
if(ufds[i].fd != CURL_SOCKET_BAD) {
fds_none = FALSE;
break;
}
}
}
if(fds_none) {
r = Curl_wait_ms(timeout_ms);
return r;
}
/* Avoid initial timestamp, avoid curlx_tvnow() call, when elapsed
time in this function does not need to be measured. This happens
when function is called with a zero timeout or a negative timeout
value indicating a blocking call should be performed. */
if(timeout_ms > 0) {
pending_ms = timeout_ms;
initial_tv = curlx_tvnow();
}
#ifdef HAVE_POLL_FINE
do {
if(timeout_ms < 0)
pending_ms = -1;
else if(!timeout_ms)
pending_ms = 0;
r = poll(ufds, nfds, pending_ms);
if(r != -1)
break;
error = SOCKERRNO;
if(error && error_not_EINTR)
break;
if(timeout_ms > 0) {
pending_ms = timeout_ms - elapsed_ms;
if(pending_ms <= 0)
break;
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
for(i = 0; i < nfds; i++) {
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
if(ufds[i].revents & POLLHUP)
ufds[i].revents |= POLLIN;
if(ufds[i].revents & POLLERR)
ufds[i].revents |= (POLLIN|POLLOUT);
}
#else /* HAVE_POLL_FINE */
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
for(i = 0; i < nfds; i++) {
ufds[i].revents = 0;
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
VERIFY_SOCK(ufds[i].fd);
if(ufds[i].events & (POLLIN|POLLOUT|POLLPRI|
POLLRDNORM|POLLWRNORM|POLLRDBAND)) {
if(ufds[i].fd > maxfd)
maxfd = ufds[i].fd;
if(ufds[i].events & (POLLRDNORM|POLLIN))
FD_SET(ufds[i].fd, &fds_read);
if(ufds[i].events & (POLLWRNORM|POLLOUT))
FD_SET(ufds[i].fd, &fds_write);
if(ufds[i].events & (POLLRDBAND|POLLPRI))
FD_SET(ufds[i].fd, &fds_err);
}
}
ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
do {
if(timeout_ms > 0) {
pending_tv.tv_sec = pending_ms / 1000;
pending_tv.tv_usec = (pending_ms % 1000) * 1000;
}
else if(!timeout_ms) {
pending_tv.tv_sec = 0;
pending_tv.tv_usec = 0;
}
r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
if(r != -1)
break;
error = SOCKERRNO;
if(error && error_not_EINTR)
break;
if(timeout_ms > 0) {
pending_ms = timeout_ms - elapsed_ms;
if(pending_ms <= 0)
break;
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
r = 0;
for(i = 0; i < nfds; i++) {
ufds[i].revents = 0;
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
if(FD_ISSET(ufds[i].fd, &fds_read))
ufds[i].revents |= POLLIN;
if(FD_ISSET(ufds[i].fd, &fds_write))
ufds[i].revents |= POLLOUT;
if(FD_ISSET(ufds[i].fd, &fds_err))
ufds[i].revents |= POLLPRI;
if(ufds[i].revents != 0)
r++;
}
#endif /* HAVE_POLL_FINE */
return r;
}
/*
* Wait for read or write events on a set of file descriptors. It uses poll()
* when a fine poll() is available, in order to avoid limits with FD_SETSIZE,
* otherwise select() is used. An error is returned if select() is being used
* and a file descriptor is too large for FD_SETSIZE.
*
* A negative timeout value makes this function wait indefinitely,
* unles no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* [bitmask] = action as described below
*
* CURL_CSELECT_IN - first socket is readable
* CURL_CSELECT_IN2 - second socket is readable
* CURL_CSELECT_OUT - write socket is writable
* CURL_CSELECT_ERR - an error condition occurred
*/
int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */
curl_socket_t readfd1,
curl_socket_t writefd, /* socket to write to */
long timeout_ms) /* milliseconds to wait */
{
#ifdef HAVE_POLL_FINE
struct pollfd pfd[3];
int num;
#else
struct timeval pending_tv;
struct timeval *ptimeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
struct timeval initial_tv = {0,0};
int pending_ms = 0;
int error;
int r;
int ret;
if((readfd0 == CURL_SOCKET_BAD) && (readfd1 == CURL_SOCKET_BAD) &&
(writefd == CURL_SOCKET_BAD)) {
/* no sockets, just wait */
r = Curl_wait_ms((int)timeout_ms);
return r;
}
/* Avoid initial timestamp, avoid curlx_tvnow() call, when elapsed
time in this function does not need to be measured. This happens
when function is called with a zero timeout or a negative timeout
value indicating a blocking call should be performed. */
if(timeout_ms > 0) {
pending_ms = (int)timeout_ms;
initial_tv = curlx_tvnow();
}
#ifdef HAVE_POLL_FINE
num = 0;
if(readfd0 != CURL_SOCKET_BAD) {
pfd[num].fd = readfd0;
pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
pfd[num].revents = 0;
num++;
}
if(readfd1 != CURL_SOCKET_BAD) {
pfd[num].fd = readfd1;
pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI;
pfd[num].revents = 0;
num++;
}
if(writefd != CURL_SOCKET_BAD) {
pfd[num].fd = writefd;
pfd[num].events = POLLWRNORM|POLLOUT;
pfd[num].revents = 0;
num++;
}
do {
if(timeout_ms < 0)
pending_ms = -1;
else if(!timeout_ms)
pending_ms = 0;
r = poll(pfd, num, pending_ms);
if(r != -1)
break;
error = SOCKERRNO;
if(error && error_not_EINTR)
break;
if(timeout_ms > 0) {
pending_ms = (int)(timeout_ms - elapsed_ms);
if(pending_ms <= 0) {
r = 0; /* Simulate a "call timed out" case */
break;
}
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
ret = 0;
num = 0;
if(readfd0 != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
ret |= CURL_CSELECT_IN;
if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
num++;
}
if(readfd1 != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP))
ret |= CURL_CSELECT_IN2;
if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL))
ret |= CURL_CSELECT_ERR;
num++;
}
if(writefd != CURL_SOCKET_BAD) {
if(pfd[num].revents & (POLLWRNORM|POLLOUT))
ret |= CURL_CSELECT_OUT;
if(pfd[num].revents & (POLLERR|POLLHUP|POLLNVAL))
ret |= CURL_CSELECT_ERR;
}
return ret;
#else /* HAVE_POLL_FINE */
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
FD_ZERO(&fds_read);
if(readfd0 != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd0);
FD_SET(readfd0, &fds_read);
FD_SET(readfd0, &fds_err);
maxfd = readfd0;
}
if(readfd1 != CURL_SOCKET_BAD) {
VERIFY_SOCK(readfd1);
FD_SET(readfd1, &fds_read);
FD_SET(readfd1, &fds_err);
if(readfd1 > maxfd)
maxfd = readfd1;
}
FD_ZERO(&fds_write);
if(writefd != CURL_SOCKET_BAD) {
VERIFY_SOCK(writefd);
FD_SET(writefd, &fds_write);
FD_SET(writefd, &fds_err);
if(writefd > maxfd)
maxfd = writefd;
}
ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
do {
if(timeout_ms > 0) {
pending_tv.tv_sec = pending_ms / 1000;
pending_tv.tv_usec = (pending_ms % 1000) * 1000;
}
else if(!timeout_ms) {
pending_tv.tv_sec = 0;
pending_tv.tv_usec = 0;
}
/* WinSock select() must not be called with an fd_set that contains zero
fd flags, or it will return WSAEINVAL. But, it also can't be called
with no fd_sets at all! From the documentation:
Any two of the parameters, readfds, writefds, or exceptfds, can be
given as null. At least one must be non-null, and any non-null
descriptor set must contain at least one handle to a socket.
We know that we have at least one bit set in at least two fd_sets in
this case, but we may have no bits set in either fds_read or fd_write,
so check for that and handle it. Luckily, with WinSock, we can _also_
ask how many bits are set on an fd_set.
It is unclear why WinSock doesn't just handle this for us instead of
calling this an error.
Note also that WinSock ignores the first argument, so we don't worry
about the fact that maxfd is computed incorrectly with WinSock (since
curl_socket_t is unsigned in such cases and thus -1 is the largest
value).
*/
r = select((int)maxfd + 1,
#ifndef USE_WINSOCK
&fds_read,
&fds_write,
#else
fds_read.fd_count ? &fds_read : NULL,
fds_write.fd_count ? &fds_write : NULL,
#endif
&fds_err, ptimeout);
if(r != -1)
break;
error = SOCKERRNO;
if(error && error_not_EINTR)
break;
if(timeout_ms > 0) {
pending_ms = timeout_ms - elapsed_ms;
if(pending_ms <= 0) {
r = 0; /* Simulate a "call timed out" case */
break;
}
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
ret = 0;
if(readfd0 != CURL_SOCKET_BAD) {
if(FD_ISSET(readfd0, &fds_read))
ret |= CURL_CSELECT_IN;
if(FD_ISSET(readfd0, &fds_err))
ret |= CURL_CSELECT_ERR;
}
if(readfd1 != CURL_SOCKET_BAD) {
if(FD_ISSET(readfd1, &fds_read))
ret |= CURL_CSELECT_IN2;
if(FD_ISSET(readfd1, &fds_err))
ret |= CURL_CSELECT_ERR;
}
if(writefd != CURL_SOCKET_BAD) {
if(FD_ISSET(writefd, &fds_write))
ret |= CURL_CSELECT_OUT;
if(FD_ISSET(writefd, &fds_err))
ret |= CURL_CSELECT_ERR;
}
return ret;
#endif /* HAVE_POLL_FINE */
}
static CURLcode easy_transfer(struct Curl_multi *multi)
{
bool done = FALSE;
CURLMcode mcode = CURLM_OK;
CURLcode result = CURLE_OK;
struct curltime before;
int without_fds = 0; /* count number of consecutive returns from
curl_multi_wait() without any filedescriptors */
while(!done && !mcode) {
int still_running = 0;
int rc;
before = curlx_tvnow();
mcode = curl_multi_wait(multi, NULL, 0, 1000, &rc);
if(!mcode) {
if(!rc) {
struct curltime after = curlx_tvnow();
/* If it returns without any filedescriptor instantly, we need to
avoid busy-looping during periods where it has nothing particular
to wait for */
if(curlx_tvdiff(after, before) <= 10) {
without_fds++;
if(without_fds > 2) {
int sleep_ms = without_fds < 10 ? (1 << (without_fds - 1)) : 1000;
Curl_wait_ms(sleep_ms);
}
}
else
/* it wasn't "instant", restart counter */
without_fds = 0;
}
else
/* got file descriptor, restart counter */
without_fds = 0;
mcode = curl_multi_perform(multi, &still_running);
}
/* only read 'still_running' if curl_multi_perform() return OK */
if(!mcode && !still_running) {
CURLMsg *msg = curl_multi_info_read(multi, &rc);
if(msg) {
result = msg->data.result;
done = TRUE;
}
}
}
/* Make sure to return some kind of error if there was a multi problem */
if(mcode) {
result = (mcode == CURLM_OUT_OF_MEMORY) ? CURLE_OUT_OF_MEMORY :
/* The other multi errors should never happen, so return
something suitably generic */
CURLE_BAD_FUNCTION_ARGUMENT;
}
return result;
}
/*
* curl_easy_perform() is the external interface that performs a blocking
* transfer as previously setup.
*
* CONCEPT: This function creates a multi handle, adds the easy handle to it,
* runs curl_multi_perform() until the transfer is done, then detaches the
* easy handle, destroys the multi handle and returns the easy handle's return
* code.
*
* REALITY: it can't just create and destroy the multi handle that easily. It
* needs to keep it around since if this easy handle is used again by this
* function, the same multi handle must be re-used so that the same pools and
* caches can be used.
*/
CURLcode curl_easy_perform(CURL *easy)
{
CURLM *multi;
CURLMcode mcode;
CURLcode code = CURLE_OK;
CURLMsg *msg;
bool done = FALSE;
int rc;
struct SessionHandle *data = easy;
int without_fds = 0; /* count number of consecutive returns from
curl_multi_wait() without any filedescriptors */
struct timeval before;
if(!easy)
return CURLE_BAD_FUNCTION_ARGUMENT;
if(data->multi) {
failf(data, "easy handled already used in multi handle");
return CURLE_FAILED_INIT;
}
if(data->multi_easy)
multi = data->multi_easy;
else {
/* this multi handle will only ever have a single easy handled attached
to it, so make it use minimal hashes */
multi = Curl_multi_handle(1, 3);
if(!multi)
return CURLE_OUT_OF_MEMORY;
data->multi_easy = multi;
}
/* Copy the MAXCONNECTS option to the multi handle */
curl_multi_setopt(multi, CURLMOPT_MAXCONNECTS, data->set.maxconnects);
mcode = curl_multi_add_handle(multi, easy);
if(mcode) {
curl_multi_cleanup(multi);
if(mcode == CURLM_OUT_OF_MEMORY)
return CURLE_OUT_OF_MEMORY;
else
return CURLE_FAILED_INIT;
}
/* assign this after curl_multi_add_handle() since that function checks for
it and rejects this handle otherwise */
data->multi = multi;
while(!done && !mcode) {
int still_running;
int ret;
before = curlx_tvnow();
mcode = curl_multi_wait(multi, NULL, 0, 1000, &ret);
if(mcode == CURLM_OK) {
if(ret == -1) {
/* poll() failed not on EINTR, indicate a network problem */
code = CURLE_RECV_ERROR;
break;
}
else if(ret == 0) {
struct timeval after = curlx_tvnow();
/* If it returns without any filedescriptor instantly, we need to
avoid busy-looping during periods where it has nothing particular
to wait for */
if(curlx_tvdiff(after, before) <= 10) {
without_fds++;
if(without_fds > 2) {
int sleep_ms = without_fds * 50;
if(sleep_ms > 1000)
sleep_ms = 1000;
Curl_wait_ms(sleep_ms);
}
}
else
/* it wasn't "instant", restart counter */
without_fds = 0;
}
else
/* got file descriptor, restart counter */
without_fds = 0;
mcode = curl_multi_perform(multi, &still_running);
}
/* only read 'still_running' if curl_multi_perform() return OK */
if((mcode == CURLM_OK) && !still_running) {
msg = curl_multi_info_read(multi, &rc);
if(msg) {
code = msg->data.result;
done = TRUE;
}
}
}
/* ignoring the return code isn't nice, but atm we can't really handle
a failure here, room for future improvement! */
(void)curl_multi_remove_handle(multi, easy);
/* The multi handle is kept alive, owned by the easy handle */
return code;
}
/*
* This is a wrapper around poll(). If poll() does not exist, then
* select() is used instead. An error is returned if select() is
* being used and a file descriptor is too large for FD_SETSIZE.
* A negative timeout value makes this function wait indefinitely,
* unless no valid file descriptor is given, when this happens the
* negative timeout is ignored and the function times out immediately.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* N = number of structures with non zero revent fields
*/
int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
{
#ifndef HAVE_POLL_FINE
struct timeval pending_tv;
struct timeval *ptimeout;
fd_set fds_read;
fd_set fds_write;
fd_set fds_err;
curl_socket_t maxfd;
#endif
struct curltime initial_tv = {0, 0};
bool fds_none = TRUE;
unsigned int i;
int pending_ms = 0;
int error;
int r;
if(ufds) {
for(i = 0; i < nfds; i++) {
if(ufds[i].fd != CURL_SOCKET_BAD) {
fds_none = FALSE;
break;
}
}
}
if(fds_none) {
r = Curl_wait_ms(timeout_ms);
return r;
}
/* Avoid initial timestamp, avoid Curl_now() call, when elapsed
time in this function does not need to be measured. This happens
when function is called with a zero timeout or a negative timeout
value indicating a blocking call should be performed. */
if(timeout_ms > 0) {
pending_ms = timeout_ms;
initial_tv = Curl_now();
}
#ifdef HAVE_POLL_FINE
do {
if(timeout_ms < 0)
pending_ms = -1;
else if(!timeout_ms)
pending_ms = 0;
r = poll(ufds, nfds, pending_ms);
if(r != -1)
break;
error = SOCKERRNO;
if(error && ERROR_NOT_EINTR(error))
break;
if(timeout_ms > 0) {
pending_ms = (int)(timeout_ms - ELAPSED_MS());
if(pending_ms <= 0) {
r = 0; /* Simulate a "call timed out" case */
break;
}
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
for(i = 0; i < nfds; i++) {
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
if(ufds[i].revents & POLLHUP)
ufds[i].revents |= POLLIN;
if(ufds[i].revents & POLLERR)
ufds[i].revents |= (POLLIN|POLLOUT);
}
#else /* HAVE_POLL_FINE */
FD_ZERO(&fds_read);
FD_ZERO(&fds_write);
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
for(i = 0; i < nfds; i++) {
ufds[i].revents = 0;
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
VERIFY_SOCK(ufds[i].fd);
if(ufds[i].events & (POLLIN|POLLOUT|POLLPRI|
POLLRDNORM|POLLWRNORM|POLLRDBAND)) {
if(ufds[i].fd > maxfd)
maxfd = ufds[i].fd;
if(ufds[i].events & (POLLRDNORM|POLLIN))
FD_SET(ufds[i].fd, &fds_read);
if(ufds[i].events & (POLLWRNORM|POLLOUT))
FD_SET(ufds[i].fd, &fds_write);
if(ufds[i].events & (POLLRDBAND|POLLPRI))
FD_SET(ufds[i].fd, &fds_err);
}
}
#ifdef USE_WINSOCK
/* WinSock select() can't handle zero events. See the comment about this in
Curl_check_socket(). */
if(fds_read.fd_count == 0 && fds_write.fd_count == 0
&& fds_err.fd_count == 0) {
r = Curl_wait_ms(timeout_ms);
return r;
}
#endif
ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
do {
if(timeout_ms > 0) {
pending_tv.tv_sec = pending_ms / 1000;
pending_tv.tv_usec = (pending_ms % 1000) * 1000;
}
else if(!timeout_ms) {
pending_tv.tv_sec = 0;
pending_tv.tv_usec = 0;
}
#ifdef USE_WINSOCK
r = select((int)maxfd + 1,
/* WinSock select() can't handle fd_sets with zero bits set, so
don't give it such arguments. See the comment about this in
Curl_check_socket().
*/
fds_read.fd_count ? &fds_read : NULL,
fds_write.fd_count ? &fds_write : NULL,
fds_err.fd_count ? &fds_err : NULL, ptimeout);
#else
r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
#endif
if(r != -1)
break;
error = SOCKERRNO;
if(error && ERROR_NOT_EINTR(error))
break;
if(timeout_ms > 0) {
pending_ms = timeout_ms - ELAPSED_MS();
if(pending_ms <= 0) {
r = 0; /* Simulate a "call timed out" case */
break;
}
}
} while(r == -1);
if(r < 0)
return -1;
if(r == 0)
return 0;
r = 0;
for(i = 0; i < nfds; i++) {
ufds[i].revents = 0;
if(ufds[i].fd == CURL_SOCKET_BAD)
continue;
if(FD_ISSET(ufds[i].fd, &fds_read))
ufds[i].revents |= POLLIN;
if(FD_ISSET(ufds[i].fd, &fds_write))
ufds[i].revents |= POLLOUT;
if(FD_ISSET(ufds[i].fd, &fds_err))
ufds[i].revents |= POLLPRI;
if(ufds[i].revents != 0)
r++;
}
#endif /* HAVE_POLL_FINE */
return r;
}
