arch/um/drivers/mconsole_user.c

   1 /*
   2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
   3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4  * Licensed under the GPL
   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 "kern_constants.h"
  14 #include "mconsole.h"
  15 #include "user.h"
  16
  17 static struct mconsole_command commands[] = {
  18         /*
  19          * With uts namespaces, uts information becomes process-specific, so
  20          * we need a process context.  If we try handling this in interrupt
  21          * context, we may hit an exiting process without a valid uts
  22          * namespace.
  23          */
  24         { "version", mconsole_version, MCONSOLE_PROC },
  25         { "halt", mconsole_halt, MCONSOLE_PROC },
  26         { "reboot", mconsole_reboot, MCONSOLE_PROC },
  27         { "config", mconsole_config, MCONSOLE_PROC },
  28         { "remove", mconsole_remove, MCONSOLE_PROC },
  29         { "sysrq", mconsole_sysrq, MCONSOLE_INTR },
  30         { "help", mconsole_help, MCONSOLE_INTR },
  31         { "cad", mconsole_cad, MCONSOLE_INTR },
  32         { "stop", mconsole_stop, MCONSOLE_PROC },
  33         { "go", mconsole_go, MCONSOLE_INTR },
  34         { "log", mconsole_log, MCONSOLE_INTR },
  35         { "proc", mconsole_proc, MCONSOLE_PROC },
  36         { "stack", mconsole_stack, MCONSOLE_INTR },
  37 };
  38
  39 /* Initialized in mconsole_init, which is an initcall */
  40 char mconsole_socket_name[256];
  41
  42 static int mconsole_reply_v0(struct mc_request *req, char *reply)
  43 {
  44         struct iovec iov;
  45         struct msghdr msg;
  46
  47         iov.iov_base = reply;
  48         iov.iov_len = strlen(reply);
  49
  50         msg.msg_name = &(req->origin);
  51         msg.msg_namelen = req->originlen;
  52         msg.msg_iov = &iov;
  53         msg.msg_iovlen = 1;
  54         msg.msg_control = NULL;
  55         msg.msg_controllen = 0;
  56         msg.msg_flags = 0;
  57
  58         return sendmsg(req->originating_fd, &msg, 0);
  59 }
  60
  61 static struct mconsole_command *mconsole_parse(struct mc_request *req)
  62 {
  63         struct mconsole_command *cmd;
  64         int i;
  65
  66         for (i = 0; i < ARRAY_SIZE(commands); i++) {
  67                 cmd = &commands[i];
  68                 if (!strncmp(req->request.data, cmd->command,
  69                             strlen(cmd->command))) {
  70                         return cmd;
  71                 }
  72         }
  73         return NULL;
  74 }
  75
  76 #define MIN(a,b) ((a)<(b) ? (a):(b))
  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 }