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