dbgport.c revision 330449 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2011 NetApp, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: stable/11/usr.sbin/bhyve/dbgport.c 330449 2018-03-05 07:26:05Z eadler $
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: stable/11/usr.sbin/bhyve/dbgport.c 330449 2018-03-05 07:26:05Z eadler $");
33
34#include <sys/types.h>
35#ifndef WITHOUT_CAPSICUM
36#include <sys/capsicum.h>
37#endif
38#include <sys/socket.h>
39#include <netinet/in.h>
40#include <netinet/tcp.h>
41#include <sys/uio.h>
42
43#include <err.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <sysexits.h>
47#include <fcntl.h>
48#include <unistd.h>
49#include <errno.h>
50
51#include "inout.h"
52#include "dbgport.h"
53#include "pci_lpc.h"
54
55#define	BVM_DBG_PORT	0x224
56#define	BVM_DBG_SIG	('B' << 8 | 'V')
57
58static int listen_fd, conn_fd;
59
60static struct sockaddr_in sin;
61
62static int
63dbg_handler(struct vmctx *ctx, int vcpu, int in, int port, int bytes,
64	    uint32_t *eax, void *arg)
65{
66	int nwritten, nread, printonce;
67	int on = 1;
68	char ch;
69
70	if (bytes == 2 && in) {
71		*eax = BVM_DBG_SIG;
72		return (0);
73	}
74
75	if (bytes != 4)
76		return (-1);
77
78again:
79	printonce = 0;
80	while (conn_fd < 0) {
81		if (!printonce) {
82			printf("Waiting for connection from gdb\r\n");
83			printonce = 1;
84		}
85		conn_fd = accept4(listen_fd, NULL, NULL, SOCK_NONBLOCK);
86		if (conn_fd >= 0) {
87			/* Avoid EPIPE after the client drops off. */
88			(void)setsockopt(conn_fd, SOL_SOCKET, SO_NOSIGPIPE,
89			    &on, sizeof(on));
90			/* Improve latency for one byte at a time tranfers. */
91			(void)setsockopt(conn_fd, IPPROTO_TCP, TCP_NODELAY,
92			    &on, sizeof(on));
93		} else if (errno != EINTR) {
94			perror("accept");
95		}
96	}
97
98	if (in) {
99		nread = read(conn_fd, &ch, 1);
100		if (nread == -1 && errno == EAGAIN)
101			*eax = -1;
102		else if (nread == 1)
103			*eax = ch;
104		else {
105			close(conn_fd);
106			conn_fd = -1;
107			goto again;
108		}
109	} else {
110		ch = *eax;
111		nwritten = write(conn_fd, &ch, 1);
112		if (nwritten != 1) {
113			close(conn_fd);
114			conn_fd = -1;
115			goto again;
116		}
117	}
118	return (0);
119}
120
121static struct inout_port dbgport = {
122	"bvmdbg",
123	BVM_DBG_PORT,
124	1,
125	IOPORT_F_INOUT,
126	dbg_handler
127};
128
129SYSRES_IO(BVM_DBG_PORT, 4);
130
131void
132init_dbgport(int sport)
133{
134	int reuse;
135#ifndef WITHOUT_CAPSICUM
136	cap_rights_t rights;
137#endif
138
139	conn_fd = -1;
140
141	if ((listen_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
142		perror("socket");
143		exit(1);
144	}
145
146	sin.sin_len = sizeof(sin);
147	sin.sin_family = AF_INET;
148	sin.sin_addr.s_addr = htonl(INADDR_ANY);
149	sin.sin_port = htons(sport);
150
151	reuse = 1;
152	if (setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &reuse,
153	    sizeof(reuse)) < 0) {
154		perror("setsockopt");
155		exit(1);
156	}
157
158	if (bind(listen_fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) {
159		perror("bind");
160		exit(1);
161	}
162
163	if (listen(listen_fd, 1) < 0) {
164		perror("listen");
165		exit(1);
166	}
167
168#ifndef WITHOUT_CAPSICUM
169	cap_rights_init(&rights, CAP_ACCEPT, CAP_READ, CAP_WRITE);
170	if (cap_rights_limit(listen_fd, &rights) == -1 && errno != ENOSYS)
171		errx(EX_OSERR, "Unable to apply rights for sandbox");
172#endif
173
174	register_inout(&dbgport);
175}
176