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 #define MIN(a,b) ((a)<(b) ? (a):(b)) 75 76 #define STRINGX(x) #x 77 #define STRING(x) STRINGX(x) 78 79 int 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 } 125 126 int 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 } 164 165 int 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 } 169 170 171 int mconsole_unlink_socket(void) 172 { 173 unlink(mconsole_socket_name); 174 return 0; 175 } 176 177 static int notify_sock = -1; 178 179 int 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