From: Stefan Metzmacher <metze@samba.org>
Date: Thu, 12 Jan 2023 10:14:06 +0000 (+0100)
Subject: lib/util: add samba_socket_{poll,sock,poll_or_sock}_error()
X-Git-Tag: talloc-2.4.2~1196
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f8213ec871016cfa380b85334192cc72589ddb7f;p=thirdparty%2Fsamba.git

lib/util: add samba_socket_{poll,sock,poll_or_sock}_error()

These are copies of the static functions in lib/tsocket/tsocket_bsd.c,
which we will replace in the next commit.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
---

diff --git a/lib/util/util_net.c b/lib/util/util_net.c
index 8a34855b8fa..acaa76ea74e 100644
--- a/lib/util/util_net.c
+++ b/lib/util/util_net.c
@@ -27,6 +27,8 @@
 #include "system/network.h"
 #include "system/locale.h"
 #include "system/filesys.h"
+#include "system/select.h"
+#include "lib/util/select.h"
 #include "lib/util/util_net.h"
 
 #undef strcasecmp
@@ -1136,3 +1138,100 @@ bool samba_sockaddr_get_port(const struct samba_sockaddr *sa, uint16_t *port)
 #endif
 	return false;
 }
+
+int samba_socket_poll_error(int fd)
+{
+	struct pollfd pfd = {
+		.fd = fd,
+#ifdef POLLRDHUP
+		.events = POLLRDHUP, /* POLLERR and POLLHUP are not needed */
+#endif
+	};
+	int ret;
+
+	errno = 0;
+	ret = sys_poll_intr(&pfd, 1, 0);
+	if (ret == 0) {
+		return 0;
+	}
+	if (ret != 1) {
+		return POLLNVAL;
+	}
+
+	if (pfd.revents & POLLERR) {
+		return POLLERR;
+	}
+	if (pfd.revents & POLLHUP) {
+		return POLLHUP;
+	}
+#ifdef POLLRDHUP
+	if (pfd.revents & POLLRDHUP) {
+		return POLLRDHUP;
+	}
+#endif
+
+	/* should never be reached! */
+	return POLLNVAL;
+}
+
+int samba_socket_sock_error(int fd)
+{
+	int ret, error = 0;
+	socklen_t len = sizeof(error);
+
+	/*
+	 * if no data is available check if the socket is in error state. For
+	 * dgram sockets it's the way to return ICMP error messages of
+	 * connected sockets to the caller.
+	 */
+	ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len);
+	if (ret == -1) {
+		return ret;
+	}
+	if (error != 0) {
+		errno = error;
+		return -1;
+	}
+	return 0;
+}
+
+int samba_socket_poll_or_sock_error(int fd)
+{
+	int ret;
+	int poll_error = 0;
+
+	poll_error = samba_socket_poll_error(fd);
+	if (poll_error == 0) {
+		return 0;
+	}
+
+#ifdef POLLRDHUP
+	if (poll_error == POLLRDHUP) {
+		errno = ECONNRESET;
+		return -1;
+	}
+#endif
+
+	if (poll_error == POLLHUP) {
+		errno = EPIPE;
+		return -1;
+	}
+
+	/*
+	 * POLLERR and POLLNVAL fallback to
+	 * getsockopt(fd, SOL_SOCKET, SO_ERROR)
+	 * and force EPIPE as fallback.
+	 */
+
+	errno = 0;
+	ret = samba_socket_sock_error(fd);
+	if (ret == 0) {
+		errno = EPIPE;
+	}
+
+	if (errno == 0) {
+		errno = EPIPE;
+	}
+
+	return -1;
+}
diff --git a/lib/util/util_net.h b/lib/util/util_net.h
index c95d90907fa..1aed45a432c 100644
--- a/lib/util/util_net.h
+++ b/lib/util/util_net.h
@@ -128,4 +128,18 @@ bool sockaddr_storage_to_samba_sockaddr(
 bool samba_sockaddr_set_port(struct samba_sockaddr *sa, uint16_t port);
 bool samba_sockaddr_get_port(const struct samba_sockaddr *sa, uint16_t *port);
 
+/*
+ * check for POLLERR or POLL*HUP
+ */
+int samba_socket_poll_error(int fd);
+/*
+ * getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len)
+ */
+int samba_socket_sock_error(int fd);
+/*
+ * check for POLL*HUP and fallback to
+ * getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len)
+ */
+int samba_socket_poll_or_sock_error(int fd);
+
 #endif /* _SAMBA_UTIL_NET_H_ */