handle Manage_subdevs() for 'external' arrays

From: Dan Williams <dan.j.williams@intel.com>

1/ Block attempts to add/remove devices from container members
2/ Forward add/remove requests to containers

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 249 insertions, 0 deletions

diff --git a/msg.c b/msg.c
new file mode 100644
index 0000000..6082365
--- /dev/null
+++ b/msg.c
@@ -0,0 +1,249 @@
+/*
+ * Copyright (C) 2008 Intel Corporation
+ *
+ * 	mdmon socket / message handling
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include "mdadm.h"
+
+enum tx_rx_state {
+	TX_RX_START,
+	TX_RX_SEQ,
+	TX_RX_NUM_BYTES,
+	TX_RX_BUF,
+	TX_RX_END,
+	TX_RX_SUCCESS,
+	TX_RX_ERR,
+};
+
+const int start_magic = 0x5a5aa5a5;
+const int end_magic = 0xa5a55a5a;
+
+#define txrx(fd, buf, size, flags) (recv_send ? \
+	recv(fd, buf, size, flags) : \
+	send(fd, buf, size, flags))
+
+/* non-blocking send/receive with n second timeout */
+static enum tx_rx_state
+tx_rx_message(int fd, struct md_message *msg, int recv_send, int tmo)
+{
+	int d = recv_send ? 0 : start_magic;
+	int flags = recv_send ? 0 : MSG_NOSIGNAL;
+	enum tx_rx_state state = TX_RX_START;
+	void *buf = &d;
+	size_t size = sizeof(d);
+	off_t n = 0;
+	int rc;
+	int again;
+
+	do {
+		again = 0;
+		rc = txrx(fd, buf + n, size - n, flags);
+		if (rc <= 0) { /* error */
+			if (rc == -1 && errno == EAGAIN)
+				again = 1;
+			else
+				state = TX_RX_ERR;
+		} else if (rc + n == size) /* done */
+			switch (state) {
+			case TX_RX_START:
+				if (recv_send && d != start_magic)
+					state = TX_RX_ERR;
+				else {
+					state = TX_RX_SEQ;
+					buf = &msg->seq;
+					size = sizeof(msg->seq);
+					n = 0;
+				}
+				break;
+			case TX_RX_SEQ:
+				state = TX_RX_NUM_BYTES;
+				buf = &msg->num_bytes;
+				size = sizeof(msg->num_bytes);
+				n = 0;
+				break;
+			case TX_RX_NUM_BYTES:
+				if (msg->num_bytes >
+				    sizeof(union md_message_commands))
+					state = TX_RX_ERR;
+				else if (recv_send && msg->num_bytes) {
+					msg->buf = malloc(msg->num_bytes);
+					if (!msg->buf)
+						state = TX_RX_ERR;
+					else {
+						state = TX_RX_BUF;
+						buf = msg->buf;
+						size = msg->num_bytes;
+						n = 0;
+					}
+				} else if (!recv_send && msg->num_bytes) {
+					state = TX_RX_BUF;
+					buf = msg->buf;
+					size = msg->num_bytes;
+					n = 0;
+				} else {
+					d = recv_send ? 0 : end_magic;
+					state = TX_RX_END;
+					buf = &d;
+					size = sizeof(d);
+					n = 0;
+				}
+				break;
+			case TX_RX_BUF:
+				d = recv_send ? 0 : end_magic;
+				state = TX_RX_END;
+				buf = &d;
+				size = sizeof(d);
+				n = 0;
+				break;
+			case TX_RX_END:
+				if (recv_send && d != end_magic)
+					state = TX_RX_ERR;
+				else
+					state = TX_RX_SUCCESS;
+				break;
+			case TX_RX_ERR:
+			case TX_RX_SUCCESS:
+				break;
+			}
+		else /* continue */
+			n += rc;
+
+		if (again) {
+			fd_set set;
+			struct timeval timeout = { tmo, 0 };
+			struct timeval *ptmo = tmo ? &timeout : NULL;
+
+			FD_ZERO(&set);
+			FD_SET(fd, &set);
+
+			if (recv_send)
+				rc = select(fd + 1, &set, NULL, NULL, ptmo);
+			else
+				rc = select(fd + 1, NULL, &set, NULL, ptmo);
+
+			if (rc <= 0)
+				state = TX_RX_ERR;
+		}
+	} while (state < TX_RX_SUCCESS);
+
+	return state;
+}
+
+
+int receive_message(int fd, struct md_message *msg, int tmo)
+{
+	if (tx_rx_message(fd, msg, 1, tmo) == TX_RX_SUCCESS)
+		return 0;
+	else
+		return -1;
+}
+
+int send_message(int fd, struct md_message *msg, int tmo)
+{
+	if (tx_rx_message(fd, msg, 0, tmo) == TX_RX_SUCCESS)
+		return 0;
+	else
+		return -1;
+}
+
+int ack(int fd, int seq, int tmo)
+{
+	struct md_message msg = { .seq = seq, .num_bytes = 0 };
+
+	return send_message(fd, &msg, tmo);
+}
+
+int nack(int fd, int err, int tmo)
+{
+	struct md_message msg = { .seq = err, .num_bytes = 0 };
+
+	return send_message(fd, &msg, tmo);
+}
+
+int send_remove_device(int fd, dev_t rdev, int seq, int tmo)
+{
+	struct md_remove_device_cmd cmd = { .action = md_action_remove_device,
+					    .rdev = rdev
+					  };
+	struct md_message msg = { .seq = seq,
+				  .num_bytes = sizeof(cmd),
+				  .buf = &cmd
+				};
+
+	return send_message(fd, &msg, tmo);
+}
+
+int connect_monitor(char *devname)
+{
+	char path[100];
+	int sfd;
+	long fl;
+	struct sockaddr_un addr;
+
+	sprintf(path, "/var/run/mdadm/%s.sock", devname);
+	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
+	if (sfd < 0)
+		return -1;
+
+	addr.sun_family = PF_LOCAL;
+	strcpy(addr.sun_path, path);
+	if (connect(sfd, &addr, sizeof(addr)) < 0) {
+		close(sfd);
+		return -1;
+	}
+
+	fl = fcntl(sfd, F_GETFL, 0);
+	fl |= O_NONBLOCK;
+	fcntl(sfd, F_SETFL, fl);
+
+	return sfd;
+}
+
+int ping_monitor(char *devname)
+{
+	int sfd = connect_monitor(devname);
+	struct md_message msg;
+	int err = 0;
+
+	if (sfd < 0)
+		return sfd;
+
+	/* try to ping existing socket */
+	if (ack(sfd, 0, 0) != 0)
+		err = -1;
+
+	/* check the reply */
+	if (!err && receive_message(sfd, &msg, 0) != 0)
+		err = -1;
+
+	if (msg.seq != 0)
+		err = -1;
+
+	close(sfd);
+	return err;
+}