1/*
2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
5 */
6
7#include <errno.h>
8#include <string.h>
9#include <unistd.h>
10#include <sys/socket.h>
11#include <sys/uio.h>
12#include <sys/un.h>
13#include "mconsole.h"
14
15static struct mconsole_command commands[] = {
16	/*
17	 * With uts namespaces, uts information becomes process-specific, so
18	 * we need a process context.  If we try handling this in interrupt
19	 * context, we may hit an exiting process without a valid uts
20	 * namespace.
21	 */
22	{ "version", mconsole_version, MCONSOLE_PROC },
23	{ "halt", mconsole_halt, MCONSOLE_PROC },
24	{ "reboot", mconsole_reboot, MCONSOLE_PROC },
25	{ "config", mconsole_config, MCONSOLE_PROC },
26	{ "remove", mconsole_remove, MCONSOLE_PROC },
27	{ "sysrq", mconsole_sysrq, MCONSOLE_INTR },
28	{ "help", mconsole_help, MCONSOLE_INTR },
29	{ "cad", mconsole_cad, MCONSOLE_INTR },
30	{ "stop", mconsole_stop, MCONSOLE_PROC },
31	{ "go", mconsole_go, MCONSOLE_INTR },
32	{ "log", mconsole_log, MCONSOLE_INTR },
33	{ "proc", mconsole_proc, MCONSOLE_PROC },
34	{ "stack", mconsole_stack, MCONSOLE_INTR },
35};
36
37/* Initialized in mconsole_init, which is an initcall */
38char mconsole_socket_name[256];
39
40static int mconsole_reply_v0(struct mc_request *req, char *reply)
41{
42	struct iovec iov;
43	struct msghdr msg;
44
45	iov.iov_base = reply;
46	iov.iov_len = strlen(reply);
47
48	msg.msg_name = &(req->origin);
49	msg.msg_namelen = req->originlen;
50	msg.msg_iov = &iov;
51	msg.msg_iovlen = 1;
52	msg.msg_control = NULL;
53	msg.msg_controllen = 0;
54	msg.msg_flags = 0;
55
56	return sendmsg(req->originating_fd, &msg, 0);
57}
58
59static struct mconsole_command *mconsole_parse(struct mc_request *req)
60{
61	struct mconsole_command *cmd;
62	int i;
63
64	for (i = 0; i < ARRAY_SIZE(commands); i++) {
65		cmd = &commands[i];
66		if (!strncmp(req->request.data, cmd->command,
67			    strlen(cmd->command))) {
68			return cmd;
69		}
70	}
71	return NULL;
72}
73
74#define MIN(a,b) ((a)<(b) ? (a):(b))
75
76#define STRINGX(x) #x
77#define STRING(x) STRINGX(x)
78
79int mconsole_get_request(int fd, struct mc_request *req)
80{
81	int len;
82
83	req->originlen = sizeof(req->origin);
84	req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
85			    (struct sockaddr *) req->origin, &req->originlen);
86	if (req->len < 0)
87		return 0;
88
89	req->originating_fd = fd;
90
91	if (req->request.magic != MCONSOLE_MAGIC) {
92		/* Unversioned request */
93		len = MIN(sizeof(req->request.data) - 1,
94			  strlen((char *) &req->request));
95		memmove(req->request.data, &req->request, len);
96		req->request.data[len] = '\0';
97
98		req->request.magic = MCONSOLE_MAGIC;
99		req->request.version = 0;
100		req->request.len = len;
101
102		mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "
103				  "not supported by this driver");
104		return 0;
105	}
106
107	if (req->request.len >= MCONSOLE_MAX_DATA) {
108		mconsole_reply(req, "Request too large", 1, 0);
109		return 0;
110	}
111	if (req->request.version != MCONSOLE_VERSION) {
112		mconsole_reply(req, "This driver only supports version "
113			       STRING(MCONSOLE_VERSION) " clients", 1, 0);
114	}
115
116	req->request.data[req->request.len] = '\0';
117	req->cmd = mconsole_parse(req);
118	if (req->cmd == NULL) {
119		mconsole_reply(req, "Unknown command", 1, 0);
120		return 0;
121	}
122
123	return 1;
124}
125
126int mconsole_reply_len(struct mc_request *req, const char *str, int total,
127		       int err, int more)
128{
129	/*
130	 * XXX This is a stack consumption problem.  It'd be nice to
131	 * make it global and serialize access to it, but there are a
132	 * ton of callers to this function.
133	 */
134	struct mconsole_reply reply;
135	int len, n;
136
137	do {
138		reply.err = err;
139
140		/* err can only be true on the first packet */
141		err = 0;
142
143		len = MIN(total, MCONSOLE_MAX_DATA - 1);
144
145		if (len == total) reply.more = more;
146		else reply.more = 1;
147
148		memcpy(reply.data, str, len);
149		reply.data[len] = '\0';
150		total -= len;
151		str += len;
152		reply.len = len + 1;
153
154		len = sizeof(reply) + reply.len - sizeof(reply.data);
155
156		n = sendto(req->originating_fd, &reply, len, 0,
157			   (struct sockaddr *) req->origin, req->originlen);
158
159		if (n < 0)
160			return -errno;
161	} while (total > 0);
162	return 0;
163}
164
165int mconsole_reply(struct mc_request *req, const char *str, int err, int more)
166{
167	return mconsole_reply_len(req, str, strlen(str), err, more);
168}
169
170
171int mconsole_unlink_socket(void)
172{
173	unlink(mconsole_socket_name);
174	return 0;
175}
176
177static int notify_sock = -1;
178
179int mconsole_notify(char *sock_name, int type, const void *data, int len)
180{
181	struct sockaddr_un target;
182	struct mconsole_notify packet;
183	int n, err = 0;
184
185	lock_notify();
186	if (notify_sock < 0) {
187		notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);
188		if (notify_sock < 0) {
189			err = -errno;
190			printk(UM_KERN_ERR "mconsole_notify - socket failed, "
191			       "errno = %d\n", errno);
192		}
193	}
194	unlock_notify();
195
196	if (err)
197		return err;
198
199	target.sun_family = AF_UNIX;
200	strcpy(target.sun_path, sock_name);
201
202	packet.magic = MCONSOLE_MAGIC;
203	packet.version = MCONSOLE_VERSION;
204	packet.type = type;
205	len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;
206	packet.len = len;
207	memcpy(packet.data, data, len);
208
209	err = 0;
210	len = sizeof(packet) + packet.len - sizeof(packet.data);
211	n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,
212		   sizeof(target));
213	if (n < 0) {
214		err = -errno;
215		printk(UM_KERN_ERR "mconsole_notify - sendto failed, "
216		       "errno = %d\n", errno);
217	}
218	return err;
219}
220