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-rw-r--r--lib/select.c126
1 files changed, 94 insertions, 32 deletions
diff --git a/lib/select.c b/lib/select.c
index 32261f2c0..1b0e8643a 100644
--- a/lib/select.c
+++ b/lib/select.c
@@ -51,6 +51,13 @@
#include "connect.h"
#include "select.h"
+#ifdef USE_WINSOCK
+# undef EINTR
+# define EINTR WSAEINTR
+# undef EINVAL
+# define EINVAL WSAEINVAL
+#endif
+
/* Winsock and TPF sockets are not in range [0..FD_SETSIZE-1] */
#if defined(USE_WINSOCK) || defined(TPF)
@@ -98,11 +105,19 @@ static void wait_ms(int timeout_ms)
/*
* This is an internal function used for waiting for read or write
- * events on single file descriptors. It attempts to replace select()
- * in order to avoid limits with FD_SETSIZE.
+ * events on a pair 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 will exit early without awaiting timeout,
+ * otherwise EINTR will be ignored.
*
* Return values:
- * -1 = system call error
+ * -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
* CSELECT_IN | CSELECT_OUT | CSELECT_ERR
*/
@@ -112,12 +127,15 @@ int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
struct pollfd pfd[2];
int num;
#else
- struct timeval timeout;
+ 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;
+ int pending_ms;
int r;
int ret;
@@ -126,23 +144,35 @@ int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
return 0;
}
+ pending_ms = timeout_ms;
+ initial_tv = curlx_tvnow();
+
#ifdef HAVE_POLL_FINE
num = 0;
if (readfd != CURL_SOCKET_BAD) {
pfd[num].fd = readfd;
pfd[num].events = POLLIN;
+ pfd[num].revents = 0;
num++;
}
if (writefd != CURL_SOCKET_BAD) {
pfd[num].fd = writefd;
pfd[num].events = POLLOUT;
+ pfd[num].revents = 0;
num++;
}
do {
- r = poll(pfd, num, timeout_ms);
- } while((r == -1) && (SOCKERRNO == EINTR));
+ if (timeout_ms < 0)
+ pending_ms = -1;
+ r = poll(pfd, num, pending_ms);
+ } while ((r == -1) && (SOCKERRNO != EINVAL) &&
+#ifdef CURL_ACKNOWLEDGE_EINTR
+ (SOCKERRNO != EINTR) &&
+#endif
+ ((timeout_ms < 0) ||
+ ((pending_ms = timeout_ms - curlx_tvdiff(curlx_tvnow(), initial_tv)) > 0)));
if (r < 0)
return -1;
@@ -176,9 +206,6 @@ int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
#else /* HAVE_POLL_FINE */
- timeout.tv_sec = timeout_ms / 1000;
- timeout.tv_usec = (timeout_ms % 1000) * 1000;
-
FD_ZERO(&fds_err);
maxfd = (curl_socket_t)-1;
@@ -199,9 +226,20 @@ int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
maxfd = writefd;
}
+ ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
+
do {
- r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, &timeout);
- } while((r == -1) && (SOCKERRNO == EINTR));
+ if (ptimeout) {
+ pending_tv.tv_sec = pending_ms / 1000;
+ pending_tv.tv_usec = (pending_ms % 1000) * 1000;
+ }
+ r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
+ } while ((r == -1) && (SOCKERRNO != EINVAL) &&
+#ifdef CURL_ACKNOWLEDGE_EINTR
+ (SOCKERRNO != EINTR) &&
+#endif
+ ((timeout_ms < 0) ||
+ ((pending_ms = timeout_ms - curlx_tvdiff(curlx_tvnow(), initial_tv)) > 0)));
if (r < 0)
return -1;
@@ -231,25 +269,33 @@ int Curl_select(curl_socket_t readfd, curl_socket_t writefd, int timeout_ms)
/*
* 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 too large for FD_SETSIZE.
+ * 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 will exit early without awaiting timeout,
+ * otherwise EINTR will be ignored.
*
* Return values:
* -1 = system call error or fd >= FD_SETSIZE
* 0 = timeout
- * 1 = number of structures with non zero revent fields
+ * 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 timeout;
+ 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;
bool fds_none = TRUE;
unsigned int i;
+ int pending_ms;
int r;
if (ufds) {
@@ -265,11 +311,21 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
return 0;
}
+ pending_ms = timeout_ms;
+ initial_tv = curlx_tvnow();
+
#ifdef HAVE_POLL_FINE
do {
- r = poll(ufds, nfds, timeout_ms);
- } while((r == -1) && (SOCKERRNO == EINTR));
+ if (timeout_ms < 0)
+ pending_ms = -1;
+ r = poll(ufds, nfds, pending_ms);
+ } while ((r == -1) && (SOCKERRNO != EINVAL) &&
+#ifdef CURL_ACKNOWLEDGE_EINTR
+ (SOCKERRNO != EINTR) &&
+#endif
+ ((timeout_ms < 0) ||
+ ((pending_ms = timeout_ms - curlx_tvdiff(curlx_tvnow(), initial_tv)) > 0)));
#else /* HAVE_POLL_FINE */
@@ -279,30 +335,36 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms)
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].fd > maxfd)
- maxfd = ufds[i].fd;
- if (ufds[i].events & POLLIN)
- FD_SET(ufds[i].fd, &fds_read);
- if (ufds[i].events & POLLOUT)
- FD_SET(ufds[i].fd, &fds_write);
- if (ufds[i].events & POLLERR)
- FD_SET(ufds[i].fd, &fds_err);
+ if (ufds[i].events & (POLLIN|POLLOUT|POLLERR)) {
+ if (ufds[i].fd > maxfd)
+ maxfd = ufds[i].fd;
+ if (ufds[i].events & POLLIN)
+ FD_SET(ufds[i].fd, &fds_read);
+ if (ufds[i].events & POLLOUT)
+ FD_SET(ufds[i].fd, &fds_write);
+ if (ufds[i].events & POLLERR)
+ FD_SET(ufds[i].fd, &fds_err);
+ }
}
- if (timeout_ms < 0) {
- ptimeout = NULL; /* wait forever */
- } else {
- timeout.tv_sec = timeout_ms / 1000;
- timeout.tv_usec = (timeout_ms % 1000) * 1000;
- ptimeout = &timeout;
- }
+ ptimeout = (timeout_ms < 0) ? NULL : &pending_tv;
do {
+ if (ptimeout) {
+ pending_tv.tv_sec = pending_ms / 1000;
+ pending_tv.tv_usec = (pending_ms % 1000) * 1000;
+ }
r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout);
- } while((r == -1) && (SOCKERRNO == EINTR));
+ } while ((r == -1) && (SOCKERRNO != EINVAL) &&
+#ifdef CURL_ACKNOWLEDGE_EINTR
+ (SOCKERRNO != EINTR) &&
+#endif
+ ((timeout_ms < 0) ||
+ ((pending_ms = timeout_ms - curlx_tvdiff(curlx_tvnow(), initial_tv)) > 0)));
if (r < 0)
return -1;
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-04 19:21:21 +0000