1 files changed, 110 insertions, 0 deletions
diff --git a/include/asterisk/select.h b/include/asterisk/select.h
new file mode 100644
index 000000000..fea8c7aff
--- /dev/null
+++ b/include/asterisk/select.h
@@ -0,0 +1,110 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2010, Digium, Inc.
+ *
+ * Tilghman Lesher <tlesher AT digium DOT com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!\file
+ * \brief Bitfield expansions for ast_select
+ */
+
+#ifndef __AST_SELECT_H
+#define __AST_SELECT_H
+
+#include <sys/select.h>
+#include <errno.h>
+#include "asterisk/utils.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern unsigned int ast_FD_SETSIZE;
+
+#if !defined(HAVE_VARIABLE_FDSET) && defined(CONFIGURE_RAN_AS_ROOT)
+#define ast_fdset fd_set
+#else
+typedef struct {
+	long fds_bits[4096 / sizeof(long)]; /* 32768 bits */
+} ast_fdset;
+
+#undef FD_ZERO
+#define FD_ZERO(a) \
+	do { \
+		long *bytes = (long *) a; \
+		int i; \
+		for (i = 0; i < sizeof(*(a)) / sizeof(long); i++) { \
+			bytes[i] = 0; \
+		} \
+	} while (0)
+#undef FD_SET
+#define FD_SET(fd, fds) \
+	do { \
+		long *bytes = (long *) fds; \
+		if (fd / sizeof(*bytes) + ((fd + 1) % sizeof(*bytes) ? 1 : 0) < sizeof(*(fds))) { \
+			bytes[fd / (sizeof(*bytes))] |= 1L << (fd % sizeof(*bytes)); \
+		} else { \
+			ast_log(LOG_ERROR, "FD %d exceeds the maximum size of ast_fdset!\n", fd); \
+		} \
+	} while (0)
+#endif /* HAVE_VARIABLE_FDSET */
+
+/*! \brief Waits for activity on a group of channels 
+ * \param nfds the maximum number of file descriptors in the sets
+ * \param rfds file descriptors to check for read availability
+ * \param wfds file descriptors to check for write availability
+ * \param efds file descriptors to check for exceptions (OOB data)
+ * \param tvp timeout while waiting for events
+ * This is the same as a standard select(), except it guarantees the
+ * behaviour where the passed struct timeval is updated with how much
+ * time was not slept while waiting for the specified events
+ */
+static inline int ast_select(int nfds, ast_fdset *rfds, ast_fdset *wfds, ast_fdset *efds, struct timeval *tvp)
+{
+#ifdef __linux__
+	ast_assert((unsigned int) nfds <= ast_FD_SETSIZE);
+	return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
+#else
+	int save_errno = 0;
+
+	ast_assert((unsigned int) nfds <= ast_FD_SETSIZE);
+	if (tvp) {
+		struct timeval tv, tvstart, tvend, tvlen;
+		int res;
+
+		tv = *tvp;
+		gettimeofday(&tvstart, NULL);
+		res = select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, tvp);
+		save_errno = errno;
+		gettimeofday(&tvend, NULL);
+		timersub(&tvend, &tvstart, &tvlen);
+		timersub(&tv, &tvlen, tvp);
+		if (tvp->tv_sec < 0 || (tvp->tv_sec == 0 && tvp->tv_usec < 0)) {
+			tvp->tv_sec = 0;
+			tvp->tv_usec = 0;
+		}
+		errno = save_errno;
+		return res;
+	}
+	else
+		return select(nfds, (fd_set *) rfds, (fd_set *) wfds, (fd_set *) efds, NULL);
+#endif
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __AST_SELECT_H */