// SPDX-License-Identifier: GPL-2.0/* * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) */ #include <errno.h>#include <string.h>#include <unistd.h>#include <sys/socket.h>#include <sys/uio.h>#include <sys/un.h>#include "mconsole.h" static struct mconsole_command commands[] = {	/*	 * With uts namespaces, uts information becomes process-specific, so	 * we need a process context.  If we try handling this in interrupt	 * context, we may hit an exiting process without a valid uts	 * namespace.	 */	{ "version", mconsole_version, MCONSOLE_PROC },	{ "halt", mconsole_halt, MCONSOLE_PROC },	{ "reboot", mconsole_reboot, MCONSOLE_PROC },	{ "config", mconsole_config, MCONSOLE_PROC },	{ "remove", mconsole_remove, MCONSOLE_PROC },	{ "sysrq", mconsole_sysrq, MCONSOLE_INTR },	{ "help", mconsole_help, MCONSOLE_INTR },	{ "cad", mconsole_cad, MCONSOLE_INTR },	{ "stop", mconsole_stop, MCONSOLE_PROC },	{ "go", mconsole_go, MCONSOLE_INTR },	{ "log", mconsole_log, MCONSOLE_INTR },	{ "proc", mconsole_proc, MCONSOLE_PROC },	{ "stack", mconsole_stack, MCONSOLE_INTR },}; /* Initialized in mconsole_init, which is an initcall */char mconsole_socket_name[256]; static int mconsole_reply_v0(struct mc_request *req, char *reply){	struct iovec iov;	struct msghdr msg; 	iov.iov_base = reply;	iov.iov_len = strlen(reply); 	msg.msg_name = &(req->origin);	msg.msg_namelen = req->originlen;	msg.msg_iov = &iov;	msg.msg_iovlen = 1;	msg.msg_control = NULL;	msg.msg_controllen = 0;	msg.msg_flags = 0; 	return sendmsg(req->originating_fd, &msg, 0);} static struct mconsole_command *mconsole_parse(struct mc_request *req){	struct mconsole_command *cmd;	int i; 	for (i = 0; i < ARRAY_SIZE(commands); i++) {		cmd = &commands[i];		if (!strncmp(req->request.data, cmd->command,			    strlen(cmd->command))) {			return cmd;		}	}	return NULL;} #ifndef MIN#define MIN(a,b) ((a)<(b) ? (a):(b))#endif #define STRINGX(x) #x#define STRING(x) STRINGX(x) int mconsole_get_request(int fd, struct mc_request *req){	int len; 	req->originlen = sizeof(req->origin);	req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,			    (struct sockaddr *) req->origin, &req->originlen);	if (req->len < 0)		return 0; 	req->originating_fd = fd; 	if (req->request.magic != MCONSOLE_MAGIC) {		/* Unversioned request */		len = MIN(sizeof(req->request.data) - 1,			  strlen((char *) &req->request));		memmove(req->request.data, &req->request, len);		req->request.data[len] = '\0'; 		req->request.magic = MCONSOLE_MAGIC;		req->request.version = 0;		req->request.len = len; 		mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "				  "not supported by this driver");		return 0;	} 	if (req->request.len >= MCONSOLE_MAX_DATA) {		mconsole_reply(req, "Request too large", 1, 0);		return 0;	}	if (req->request.version != MCONSOLE_VERSION) {		mconsole_reply(req, "This driver only supports version "			       STRING(MCONSOLE_VERSION) " clients", 1, 0);	} 	req->request.data[req->request.len] = '\0';	req->cmd = mconsole_parse(req);	if (req->cmd == NULL) {		mconsole_reply(req, "Unknown command", 1, 0);		return 0;	} 	return 1;} int mconsole_reply_len(struct mc_request *req, const char *str, int total,		       int err, int more){	/*	 * XXX This is a stack consumption problem.  It'd be nice to	 * make it global and serialize access to it, but there are a	 * ton of callers to this function.	 */	struct mconsole_reply reply;	int len, n; 	do {		reply.err = err; 		/* err can only be true on the first packet */		err = 0; 		len = MIN(total, MCONSOLE_MAX_DATA - 1); 		if (len == total) reply.more = more;		else reply.more = 1; 		memcpy(reply.data, str, len);		reply.data[len] = '\0';		total -= len;		str += len;		reply.len = len + 1; 		len = sizeof(reply) + reply.len - sizeof(reply.data); 		n = sendto(req->originating_fd, &reply, len, 0,			   (struct sockaddr *) req->origin, req->originlen); 		if (n < 0)			return -errno;	} while (total > 0);	return 0;} int mconsole_reply(struct mc_request *req, const char *str, int err, int more){	return mconsole_reply_len(req, str, strlen(str), err, more);}  int mconsole_unlink_socket(void){	unlink(mconsole_socket_name);	return 0;} static int notify_sock = -1; int mconsole_notify(char *sock_name, int type, const void *data, int len){	struct sockaddr_un target;	struct mconsole_notify packet;	int n, err = 0; 	lock_notify();	if (notify_sock < 0) {		notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);		if (notify_sock < 0) {			err = -errno;			printk(UM_KERN_ERR "mconsole_notify - socket failed, "			       "errno = %d\n", errno);		}	}	unlock_notify(); 	if (err)		return err; 	target.sun_family = AF_UNIX;	strcpy(target.sun_path, sock_name); 	packet.magic = MCONSOLE_MAGIC;	packet.version = MCONSOLE_VERSION;	packet.type = type;	len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;	packet.len = len;	memcpy(packet.data, data, len); 	err = 0;	len = sizeof(packet) + packet.len - sizeof(packet.data);	n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,		   sizeof(target));	if (n < 0) {		err = -errno;		printk(UM_KERN_ERR "mconsole_notify - sendto failed, "		       "errno = %d\n", errno);	}	return err;}