1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
4 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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
15 static 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 */
38 char mconsole_socket_name[256];
39
40 static 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
59 static 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 #ifndef MIN
75 #define MIN(a,b) ((a)<(b) ? (a):(b))
76 #endif
77
78 #define STRINGX(x) #x
79 #define STRING(x) STRINGX(x)
80
81 int mconsole_get_request(int fd, struct mc_request *req)
82 {
83 int len;
84
85 req->originlen = sizeof(req->origin);
86 req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
87 (struct sockaddr *) req->origin, &req->originlen);
88 if (req->len < 0)
89 return 0;
90
91 req->originating_fd = fd;
92
93 if (req->request.magic != MCONSOLE_MAGIC) {
94 /* Unversioned request */
95 len = MIN(sizeof(req->request.data) - 1,
96 strlen((char *) &req->request));
97 memmove(req->request.data, &req->request, len);
98 req->request.data[len] = '\0';
99
100 req->request.magic = MCONSOLE_MAGIC;
101 req->request.version = 0;
102 req->request.len = len;
103
104 mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "
105 "not supported by this driver");
106 return 0;
107 }
108
109 if (req->request.len >= MCONSOLE_MAX_DATA) {
110 mconsole_reply(req, "Request too large", 1, 0);
111 return 0;
112 }
113 if (req->request.version != MCONSOLE_VERSION) {
114 mconsole_reply(req, "This driver only supports version "
115 STRING(MCONSOLE_VERSION) " clients", 1, 0);
116 }
117
118 req->request.data[req->request.len] = '\0';
119 req->cmd = mconsole_parse(req);
120 if (req->cmd == NULL) {
121 mconsole_reply(req, "Unknown command", 1, 0);
122 return 0;
123 }
124
125 return 1;
126 }
127
128 int mconsole_reply_len(struct mc_request *req, const char *str, int total,
129 int err, int more)
130 {
131 /*
132 * XXX This is a stack consumption problem. It'd be nice to
133 * make it global and serialize access to it, but there are a
134 * ton of callers to this function.
135 */
136 struct mconsole_reply reply;
137 int len, n;
138
139 do {
140 reply.err = err;
141
142 /* err can only be true on the first packet */
143 err = 0;
144
145 len = MIN(total, MCONSOLE_MAX_DATA - 1);
146
147 if (len == total) reply.more = more;
148 else reply.more = 1;
149
150 memcpy(reply.data, str, len);
151 reply.data[len] = '\0';
152 total -= len;
153 str += len;
154 reply.len = len + 1;
155
156 len = sizeof(reply) + reply.len - sizeof(reply.data);
157
158 n = sendto(req->originating_fd, &reply, len, 0,
159 (struct sockaddr *) req->origin, req->originlen);
160
161 if (n < 0)
162 return -errno;
163 } while (total > 0);
164 return 0;
165 }
166
167 int mconsole_reply(struct mc_request *req, const char *str, int err, int more)
168 {
169 return mconsole_reply_len(req, str, strlen(str), err, more);
170 }
171
172
173 int mconsole_unlink_socket(void)
174 {
175 unlink(mconsole_socket_name);
176 return 0;
177 }
178
179 static int notify_sock = -1;
180
181 int mconsole_notify(char *sock_name, int type, const void *data, int len)
182 {
183 struct sockaddr_un target;
184 struct mconsole_notify packet;
185 int n, err = 0;
186
187 lock_notify();
188 if (notify_sock < 0) {
189 notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);
190 if (notify_sock < 0) {
191 err = -errno;
192 printk(UM_KERN_ERR "mconsole_notify - socket failed, "
193 "errno = %d\n", errno);
194 }
195 }
196 unlock_notify();
197
198 if (err)
199 return err;
200
201 target.sun_family = AF_UNIX;
202 strcpy(target.sun_path, sock_name);
203
204 packet.magic = MCONSOLE_MAGIC;
205 packet.version = MCONSOLE_VERSION;
206 packet.type = type;
207 len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;
208 packet.len = len;
209 memcpy(packet.data, data, len);
210
211 err = 0;
212 len = sizeof(packet) + packet.len - sizeof(packet.data);
213 n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,
214 sizeof(target));
215 if (n < 0) {
216 err = -errno;
217 printk(UM_KERN_ERR "mconsole_notify - sendto failed, "
218 "errno = %d\n", errno);
219 }
220 return err;
221 }
222
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