Line data    Source code

       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           0 : static int mconsole_reply_v0(struct mc_request *req, char *reply)
      41             : {
      42             :         struct iovec iov;
      43             :         struct msghdr msg;
      44             : 
      45           0 :         iov.iov_base = reply;
      46           0 :         iov.iov_len = strlen(reply);
      47             : 
      48           0 :         msg.msg_name = &(req->origin);
      49           0 :         msg.msg_namelen = req->originlen;
      50           0 :         msg.msg_iov = &iov;
      51           0 :         msg.msg_iovlen = 1;
      52           0 :         msg.msg_control = NULL;
      53           0 :         msg.msg_controllen = 0;
      54           0 :         msg.msg_flags = 0;
      55             : 
      56           0 :         return sendmsg(req->originating_fd, &msg, 0);
      57             : }
      58             : 
      59           0 : static struct mconsole_command *mconsole_parse(struct mc_request *req)
      60             : {
      61             :         struct mconsole_command *cmd;
      62             :         int i;
      63             : 
      64           0 :         for (i = 0; i < ARRAY_SIZE(commands); i++) {
      65           0 :                 cmd = &commands[i];
      66           0 :                 if (!strncmp(req->request.data, cmd->command,
      67           0 :                             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           0 : int mconsole_get_request(int fd, struct mc_request *req)
      80             : {
      81             :         int len;
      82             : 
      83           0 :         req->originlen = sizeof(req->origin);
      84           0 :         req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
      85           0 :                             (struct sockaddr *) req->origin, &req->originlen);
      86           0 :         if (req->len < 0)
      87             :                 return 0;
      88             : 
      89           0 :         req->originating_fd = fd;
      90             : 
      91           0 :         if (req->request.magic != MCONSOLE_MAGIC) {
      92             :                 /* Unversioned request */
      93           0 :                 len = MIN(sizeof(req->request.data) - 1,
      94             :                           strlen((char *) &req->request));
      95           0 :                 memmove(req->request.data, &req->request, len);
      96           0 :                 req->request.data[len] = '\0';
      97             : 
      98           0 :                 req->request.magic = MCONSOLE_MAGIC;
      99           0 :                 req->request.version = 0;
     100           0 :                 req->request.len = len;
     101             : 
     102           0 :                 mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "
     103             :                                   "not supported by this driver");
     104           0 :                 return 0;
     105             :         }
     106             : 
     107           0 :         if (req->request.len >= MCONSOLE_MAX_DATA) {
     108           0 :                 mconsole_reply(req, "Request too large", 1, 0);
     109           0 :                 return 0;
     110             :         }
     111           0 :         if (req->request.version != MCONSOLE_VERSION) {
     112           0 :                 mconsole_reply(req, "This driver only supports version "
     113             :                                STRING(MCONSOLE_VERSION) " clients", 1, 0);
     114             :         }
     115             : 
     116           0 :         req->request.data[req->request.len] = '\0';
     117           0 :         req->cmd = mconsole_parse(req);
     118           0 :         if (req->cmd == NULL) {
     119           0 :                 mconsole_reply(req, "Unknown command", 1, 0);
     120           0 :                 return 0;
     121             :         }
     122             : 
     123             :         return 1;
     124             : }
     125             : 
     126           0 : 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           0 :                 reply.err = err;
     139             : 
     140             :                 /* err can only be true on the first packet */
     141           0 :                 err = 0;
     142             : 
     143           0 :                 len = MIN(total, MCONSOLE_MAX_DATA - 1);
     144             : 
     145           0 :                 if (len == total) reply.more = more;
     146           0 :                 else reply.more = 1;
     147             : 
     148           0 :                 memcpy(reply.data, str, len);
     149           0 :                 reply.data[len] = '\0';
     150           0 :                 total -= len;
     151           0 :                 str += len;
     152           0 :                 reply.len = len + 1;
     153             : 
     154           0 :                 len = sizeof(reply) + reply.len - sizeof(reply.data);
     155             : 
     156           0 :                 n = sendto(req->originating_fd, &reply, len, 0,
     157           0 :                            (struct sockaddr *) req->origin, req->originlen);
     158             : 
     159           0 :                 if (n < 0)
     160           0 :                         return -errno;
     161           0 :         } while (total > 0);
     162             :         return 0;
     163             : }
     164             : 
     165           0 : int mconsole_reply(struct mc_request *req, const char *str, int err, int more)
     166             : {
     167           0 :         return mconsole_reply_len(req, str, strlen(str), err, more);
     168             : }
     169             : 
     170             : 
     171           1 : int mconsole_unlink_socket(void)
     172             : {
     173           1 :         unlink(mconsole_socket_name);
     174           1 :         return 0;
     175             : }
     176             : 
     177             : static int notify_sock = -1;
     178             : 
     179           0 : 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           0 :         int n, err = 0;
     184             : 
     185           0 :         lock_notify();
     186           0 :         if (notify_sock < 0) {
     187           0 :                 notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);
     188           0 :                 if (notify_sock < 0) {
     189           0 :                         err = -errno;
     190           0 :                         printk(UM_KERN_ERR "mconsole_notify - socket failed, "
     191             :                                "errno = %d\n", errno);
     192             :                 }
     193             :         }
     194           0 :         unlock_notify();
     195             : 
     196           0 :         if (err)
     197             :                 return err;
     198             : 
     199           0 :         target.sun_family = AF_UNIX;
     200           0 :         strcpy(target.sun_path, sock_name);
     201             : 
     202           0 :         packet.magic = MCONSOLE_MAGIC;
     203           0 :         packet.version = MCONSOLE_VERSION;
     204           0 :         packet.type = type;
     205           0 :         len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;
     206           0 :         packet.len = len;
     207           0 :         memcpy(packet.data, data, len);
     208             : 
     209           0 :         err = 0;
     210           0 :         len = sizeof(packet) + packet.len - sizeof(packet.data);
     211           0 :         n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,
     212             :                    sizeof(target));
     213           0 :         if (n < 0) {
     214           0 :                 err = -errno;
     215           0 :                 printk(UM_KERN_ERR "mconsole_notify - sendto failed, "
     216             :                        "errno = %d\n", errno);
     217             :         }
     218             :         return err;
     219             : }