libports: add poll() to libc

Implements poll() via select() for certain programs like OpenSSH
which need it.

(This implementation is actually based OpenSSHp's compat function.)

libports/lib/mk/libc.mk

@@ -14,7 +14,7 @@ SRC_CC = atexit.cc dummies.cc rlimit.cc sysctl.cc readlink.cc munmap.cc \
          issetugid.cc errno.cc gai_strerror.cc clock_gettime.cc \
          gettimeofday.cc malloc.cc progname.cc fd_alloc.cc file_operations.cc \
          plugin.cc plugin_registry.cc select.cc exit.cc environ.cc nanosleep.cc \
-         libc_mem_alloc.cc pread_pwrite.cc readv_writev.cc
+         libc_mem_alloc.cc pread_pwrite.cc readv_writev.cc poll.cc
 
 #
 # Files from string library that are not included in libc-raw_string because

libports/src/lib/libc/poll.cc

@@ -0,0 +1,130 @@
+/*
+ * \brief  poll() implementation
+ * \author Josef Soentgen
+ * \date   2012-07-12
+ *
+ * this 'poll()' implementation is based on OpenSSHp's and
+ * uses our 'select()' function internally.
+ */
+
+/*
+ * Copyright (C) 2010-2012 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#include <base/printf.h>
+#include <os/timed_semaphore.h>
+
+#include <libc-plugin/plugin_registry.h>
+#include <libc-plugin/plugin.h>
+
+#include <sys/select.h>
+#include <sys/poll.h>
+#include <stdlib.h>
+
+using namespace Libc;
+
+
+/**
+ * The poll function was taken from OpenSSH portable (bsd-poll.c) and adepted
+ * to better fit within Genode's libc.
+ *
+ * Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+extern "C" int
+__attribute__((weak))
+poll(struct pollfd fds[], nfds_t nfds, int timeout)
+{
+	nfds_t i;
+	int saved_errno, ret, fd, maxfd = 0;
+	fd_set *readfds = NULL, *writefds = NULL, *exceptfds = NULL;
+	size_t nmemb;
+	struct timeval tv, *tvp = NULL;
+
+	for (i = 0; i < nfds; i++) {
+		fd = fds[i].fd;
+		if (fd >= FD_SETSIZE) {
+			/*errno = EINVAL;*/
+			return -1;
+		}
+		maxfd = MAX(maxfd, fd);
+	}
+
+	nmemb = howmany(maxfd + 1 , NFDBITS);
+	if ((readfds = (fd_set *) calloc(nmemb, sizeof(fd_mask))) == NULL ||
+	    (writefds = (fd_set *) calloc(nmemb, sizeof(fd_mask))) == NULL ||
+	    (exceptfds = (fd_set *) calloc(nmemb, sizeof(fd_mask))) == NULL) {
+		/*saved_errno = ENOMEM;*/
+		ret = -1;
+		goto out;
+	}
+
+	/* populate event bit vectors for the events we're interested in */
+	for (i = 0; i < nfds; i++) {
+		fd = fds[i].fd;
+		if (fd == -1)
+			continue;
+		if (fds[i].events & POLLIN) {
+			FD_SET(fd, readfds);
+			FD_SET(fd, exceptfds);
+		}
+		if (fds[i].events & POLLOUT) {
+			FD_SET(fd, writefds);
+			FD_SET(fd, exceptfds);
+		}
+	}
+
+	/* poll timeout is msec, select is timeval (sec + usec) */
+	if (timeout >= 0) {
+		tv.tv_sec = timeout / 1000;
+		tv.tv_usec = (timeout % 1000) * 1000;
+		tvp = &tv;
+	}
+
+	ret = select(maxfd + 1, readfds, writefds, exceptfds, tvp);
+	/*saved_errno = errno;*/
+
+	/* scan through select results and set poll() flags */
+	for (i = 0; i < nfds; i++) {
+		fd = fds[i].fd;
+		fds[i].revents = 0;
+		if (fd == -1)
+			continue;
+		if (FD_ISSET(fd, readfds)) {
+			fds[i].revents |= POLLIN;
+		}
+		if (FD_ISSET(fd, writefds)) {
+			fds[i].revents |= POLLOUT;
+		}
+		if (FD_ISSET(fd, exceptfds)) {
+			fds[i].revents |= POLLERR;
+		}
+	}
+
+out:    
+	if (readfds != NULL)
+		free(readfds);
+	if (writefds != NULL)
+		free(writefds);
+	if (exceptfds != NULL)
+		free(exceptfds);
+	/*
+	if (ret == -1)
+		errno = saved_errno;
+	*/
+	return ret;
+}