diff options
| -rw-r--r-- | lib/select.c | 164 | ||||
| -rw-r--r-- | lib/select.h | 6 |
2 files changed, 89 insertions, 81 deletions
diff --git a/lib/select.c b/lib/select.c index b372efff1..b9d7d6569 100644 --- a/lib/select.c +++ b/lib/select.c @@ -101,6 +101,76 @@ int Curl_wait_ms(int timeout_ms) } /* + * This is a wrapper around select() to aid in Windows compatibility. + * 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 signalled file descriptors + */ +int Curl_select(curl_socket_t maxfd, + fd_set *fds_read, + fd_set *fds_write, + fd_set *fds_err, + time_t timeout_ms) /* milliseconds to wait */ +{ + struct timeval pending_tv; + struct timeval *ptimeout; + int pending_ms = 0; + int r; + +#ifdef USE_WINSOCK + /* WinSock select() can't handle zero events. See the comment below. */ + if((!fds_read || fds_read->fd_count == 0) && + (!fds_write || fds_write->fd_count == 0) && + (!fds_err || fds_err->fd_count == 0)) { + r = Curl_wait_ms((int)timeout_ms); + return r; + } +#endif + + ptimeout = &pending_tv; + + if(timeout_ms < 0) { + ptimeout = NULL; + } + else if(timeout_ms > 0) { + pending_ms = (int)timeout_ms; + 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 + /* 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. + + It is unclear why WinSock doesn't just handle this for us instead of + calling this an error. + */ + r = select((int)maxfd + 1, + fds_read && fds_read->fd_count ? fds_read : NULL, + fds_write && fds_write->fd_count ? fds_write : NULL, + fds_err && fds_err->fd_count ? fds_err : NULL, ptimeout); +#else + r = select((int)maxfd + 1, fds_read, fds_write, fds_err, ptimeout); +#endif + + 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 @@ -127,16 +197,14 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */ { #ifdef HAVE_POLL_FINE struct pollfd pfd[3]; + int pending_ms = 0; 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 - int pending_ms = 0; int r; int ret; @@ -158,10 +226,6 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */ 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; - } - #ifdef HAVE_POLL_FINE num = 0; @@ -184,7 +248,9 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */ num++; } - if(timeout_ms < 0) + if(timeout_ms > 0) + pending_ms = (int)timeout_ms; + else if(timeout_ms < 0) pending_ms = -1; else if(!timeout_ms) pending_ms = 0; @@ -249,46 +315,17 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */ maxfd = writefd; } - ptimeout = (timeout_ms < 0) ? NULL : &pending_tv; - - 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 + /* 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). */ -#ifdef USE_WINSOCK - r = select((int)maxfd + 1, - fds_read.fd_count ? &fds_read : NULL, - fds_write.fd_count ? &fds_write : NULL, - &fds_err, ptimeout); -#else - r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout); -#endif + r = Curl_select(maxfd, &fds_read, &fds_write, &fds_err, timeout_ms); if(r < 0) return -1; @@ -336,9 +373,9 @@ int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */ */ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) { -#ifndef HAVE_POLL_FINE - struct timeval pending_tv; - struct timeval *ptimeout; +#ifdef HAVE_POLL_FINE + int pending_ms = 0; +#else fd_set fds_read; fd_set fds_write; fd_set fds_err; @@ -346,7 +383,6 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) #endif bool fds_none = TRUE; unsigned int i; - int pending_ms = 0; int r; if(ufds) { @@ -367,13 +403,11 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) 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; - } - #ifdef HAVE_POLL_FINE - if(timeout_ms < 0) + if(timeout_ms > 0) + pending_ms = timeout_ms; + else if(timeout_ms < 0) pending_ms = -1; else if(!timeout_ms) pending_ms = 0; @@ -418,39 +452,7 @@ int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) } } -#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; - - 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 + r = Curl_select(maxfd, &fds_read, &fds_write, &fds_err, timeout_ms); if(r < 0) return -1; diff --git a/lib/select.h b/lib/select.h index ec3021aac..56fe30367 100644 --- a/lib/select.h +++ b/lib/select.h @@ -72,6 +72,12 @@ struct pollfd therefore defined here */ #define CURL_CSELECT_IN2 (CURL_CSELECT_ERR << 1) +int Curl_select(curl_socket_t maxfd, + fd_set *fds_read, + fd_set *fds_write, + fd_set *fds_err, + time_t timeout_ms); + int Curl_socket_check(curl_socket_t readfd, curl_socket_t readfd2, curl_socket_t writefd, time_t timeout_ms); |