proto_common.c revision 220272 
1/*-
2 * Copyright (c) 2009-2010 The FreeBSD Foundation
3 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>
4 * All rights reserved.
5 *
6 * This software was developed by Pawel Jakub Dawidek under sponsorship from
7 * the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: head/sbin/hastd/proto_common.c 220272 2011-04-02 09:29:53Z pjd $");
33
34#include <sys/types.h>
35#include <sys/socket.h>
36
37#include <errno.h>
38#include <fcntl.h>
39#include <stdbool.h>
40#include <stdlib.h>
41#include <strings.h>
42#include <unistd.h>
43
44#include "pjdlog.h"
45#include "proto_impl.h"
46
47/* Maximum size of packet we want to use when sending data. */
48#ifndef MAX_SEND_SIZE
49#define	MAX_SEND_SIZE	32768
50#endif
51
52static bool
53blocking_socket(int sock)
54{
55	int flags;
56
57	flags = fcntl(sock, F_GETFL);
58	PJDLOG_ASSERT(flags >= 0);
59	return ((flags & O_NONBLOCK) == 0);
60}
61
62static int
63proto_descriptor_send(int sock, int fd)
64{
65	unsigned char ctrl[CMSG_SPACE(sizeof(fd))];
66	struct msghdr msg;
67	struct cmsghdr *cmsg;
68
69	PJDLOG_ASSERT(sock >= 0);
70	PJDLOG_ASSERT(fd >= 0);
71
72	bzero(&msg, sizeof(msg));
73	bzero(&ctrl, sizeof(ctrl));
74
75	msg.msg_iov = NULL;
76	msg.msg_iovlen = 0;
77	msg.msg_control = ctrl;
78	msg.msg_controllen = sizeof(ctrl);
79
80	cmsg = CMSG_FIRSTHDR(&msg);
81	cmsg->cmsg_level = SOL_SOCKET;
82	cmsg->cmsg_type = SCM_RIGHTS;
83	cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
84	bcopy(&fd, CMSG_DATA(cmsg), sizeof(fd));
85
86	if (sendmsg(sock, &msg, 0) == -1)
87		return (errno);
88
89	return (0);
90}
91
92int
93proto_common_send(int sock, const unsigned char *data, size_t size, int fd)
94{
95	ssize_t done;
96	size_t sendsize;
97
98	PJDLOG_ASSERT(sock >= 0);
99
100	if (data == NULL) {
101		/* The caller is just trying to decide about direction. */
102
103		PJDLOG_ASSERT(size == 0);
104
105		if (shutdown(sock, SHUT_RD) == -1)
106			return (errno);
107		return (0);
108	}
109
110	PJDLOG_ASSERT(data != NULL);
111	PJDLOG_ASSERT(size > 0);
112
113	do {
114		sendsize = size < MAX_SEND_SIZE ? size : MAX_SEND_SIZE;
115		done = send(sock, data, sendsize, MSG_NOSIGNAL);
116		if (done == 0) {
117			return (ENOTCONN);
118		} else if (done < 0) {
119			if (errno == EINTR)
120				continue;
121			/*
122			 * If this is blocking socket and we got EAGAIN, this
123			 * means the request timed out. Translate errno to
124			 * ETIMEDOUT, to give administrator a hint to
125			 * eventually increase timeout.
126			 */
127			if (errno == EAGAIN && blocking_socket(sock))
128				errno = ETIMEDOUT;
129			return (errno);
130		}
131		data += done;
132		size -= done;
133	} while (size > 0);
134
135	if (fd == -1)
136		return (0);
137	return (proto_descriptor_send(sock, fd));
138}
139
140static int
141proto_descriptor_recv(int sock, int *fdp)
142{
143	unsigned char ctrl[CMSG_SPACE(sizeof(*fdp))];
144	struct msghdr msg;
145	struct cmsghdr *cmsg;
146
147	PJDLOG_ASSERT(sock >= 0);
148	PJDLOG_ASSERT(fdp != NULL);
149
150	bzero(&msg, sizeof(msg));
151	bzero(&ctrl, sizeof(ctrl));
152
153	msg.msg_iov = NULL;
154	msg.msg_iovlen = 0;
155	msg.msg_control = ctrl;
156	msg.msg_controllen = sizeof(ctrl);
157
158	if (recvmsg(sock, &msg, 0) == -1)
159		return (errno);
160
161	cmsg = CMSG_FIRSTHDR(&msg);
162	if (cmsg->cmsg_level != SOL_SOCKET ||
163	    cmsg->cmsg_type != SCM_RIGHTS) {
164		return (EINVAL);
165	}
166	bcopy(CMSG_DATA(cmsg), fdp, sizeof(*fdp));
167
168	return (0);
169}
170
171int
172proto_common_recv(int sock, unsigned char *data, size_t size, int *fdp)
173{
174	ssize_t done;
175
176	PJDLOG_ASSERT(sock >= 0);
177
178	if (data == NULL) {
179		/* The caller is just trying to decide about direction. */
180
181		PJDLOG_ASSERT(size == 0);
182
183		if (shutdown(sock, SHUT_WR) == -1)
184			return (errno);
185		return (0);
186	}
187
188	PJDLOG_ASSERT(data != NULL);
189	PJDLOG_ASSERT(size > 0);
190
191	do {
192		done = recv(sock, data, size, MSG_WAITALL);
193	} while (done == -1 && errno == EINTR);
194	if (done == 0) {
195		return (ENOTCONN);
196	} else if (done < 0) {
197		/*
198		 * If this is blocking socket and we got EAGAIN, this
199		 * means the request timed out. Translate errno to
200		 * ETIMEDOUT, to give administrator a hint to
201		 * eventually increase timeout.
202		 */
203		if (errno == EAGAIN && blocking_socket(sock))
204			errno = ETIMEDOUT;
205		return (errno);
206	}
207	if (fdp == NULL)
208		return (0);
209	return (proto_descriptor_recv(sock, fdp));
210}
211