arch/um/drivers/mconsole_user.c

   1 /*
   2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
   3  * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
   4  * Licensed under the GPL
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <errno.h>
  10 #include <signal.h>
  11 #include <sys/socket.h>
  12 #include <sys/types.h>
  13 #include <sys/uio.h>
  14 #include <sys/un.h>
  15 #include <unistd.h>
  16 #include "user.h"
  17 #include "sysdep/ptrace.h"
  18 #include "mconsole.h"
  19 #include "os.h"
  20
  21 static struct mconsole_command commands[] = {
  22         /* With uts namespaces, uts information becomes process-specific, so
  23          * we need a process context.  If we try handling this in interrupt
  24          * context, we may hit an exiting process without a valid uts
  25          * namespace.
  26          */
  27         { "version", mconsole_version, MCONSOLE_PROC },
  28         { "halt", mconsole_halt, MCONSOLE_PROC },
  29         { "reboot", mconsole_reboot, MCONSOLE_PROC },
  30         { "config", mconsole_config, MCONSOLE_PROC },
  31         { "remove", mconsole_remove, MCONSOLE_PROC },
  32         { "sysrq", mconsole_sysrq, MCONSOLE_INTR },
  33         { "help", mconsole_help, MCONSOLE_INTR },
  34         { "cad", mconsole_cad, MCONSOLE_INTR },
  35         { "stop", mconsole_stop, MCONSOLE_PROC },
  36         { "go", mconsole_go, MCONSOLE_INTR },
  37         { "log", mconsole_log, MCONSOLE_INTR },
  38         { "proc", mconsole_proc, MCONSOLE_PROC },
  39         { "stack", mconsole_stack, MCONSOLE_INTR },
  40 };
  41
  42 /* Initialized in mconsole_init, which is an initcall */
  43 char mconsole_socket_name[256];
  44
  45 int mconsole_reply_v0(struct mc_request *req, char *reply)
  46 {
  47         struct iovec iov;
  48         struct msghdr msg;
  49
  50         iov.iov_base = reply;
  51         iov.iov_len = strlen(reply);
  52
  53         msg.msg_name = &(req->origin);
  54         msg.msg_namelen = req->originlen;
  55         msg.msg_iov = &iov;
  56         msg.msg_iovlen = 1;
  57         msg.msg_control = NULL;
  58         msg.msg_controllen = 0;
  59         msg.msg_flags = 0;
  60
  61         return sendmsg(req->originating_fd, &msg, 0);
  62 }
  63
  64 static struct mconsole_command *mconsole_parse(struct mc_request *req)
  65 {
  66         struct mconsole_command *cmd;
  67         int i;
  68
  69         for(i = 0; i < ARRAY_SIZE(commands); i++){
  70                 cmd = &commands[i];
  71                 if(!strncmp(req->request.data, cmd->command,
  72                             strlen(cmd->command))){
  73                         return cmd;
  74                 }
  75         }
  76         return NULL;
  77 }
  78
  79 #define MIN(a,b) ((a)<(b) ? (a):(b))
  80
  81 #define STRINGX(x) #x
  82 #define STRING(x) STRINGX(x)
  83
  84 int mconsole_get_request(int fd, struct mc_request *req)
  85 {
  86         int len;
  87
  88         req->originlen = sizeof(req->origin);
  89         req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
  90                             (struct sockaddr *) req->origin, &req->originlen);
  91         if (req->len < 0)
  92                 return 0;
  93
  94         req->originating_fd = fd;
  95
  96         if(req->request.magic != MCONSOLE_MAGIC){
  97                 /* Unversioned request */
  98                 len = MIN(sizeof(req->request.data) - 1,
  99                           strlen((char *) &req->request));
 100                 memmove(req->request.data, &req->request, len);
 101                 req->request.data[len] = '\0';
 102
 103                 req->request.magic = MCONSOLE_MAGIC;
 104                 req->request.version = 0;
 105                 req->request.len = len;
 106
 107                 mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "
 108                                   "not supported by this driver");
 109                 return(0);
 110         }
 111
 112         if(req->request.len >= MCONSOLE_MAX_DATA){
 113                 mconsole_reply(req, "Request too large", 1, 0);
 114                 return(0);
 115         }
 116         if(req->request.version != MCONSOLE_VERSION){
 117                 mconsole_reply(req, "This driver only supports version "
 118                                STRING(MCONSOLE_VERSION) " clients", 1, 0);
 119         }
 120
 121         req->request.data[req->request.len] = '\0';
 122         req->cmd = mconsole_parse(req);
 123         if(req->cmd == NULL){
 124                 mconsole_reply(req, "Unknown command", 1, 0);
 125                 return(0);
 126         }
 127
 128         return(1);
 129 }
 130
 131 int mconsole_reply_len(struct mc_request *req, const char *str, int total,
 132                        int err, int more)
 133 {
 134         /* XXX This is a stack consumption problem.  It'd be nice to
 135          * make it global and serialize access to it, but there are a
 136          * ton of callers to this function.
 137          */
 138         struct mconsole_reply reply;
 139         int len, n;
 140
 141         do {
 142                 reply.err = err;
 143
 144                 /* err can only be true on the first packet */
 145                 err = 0;
 146
 147                 len = MIN(total, MCONSOLE_MAX_DATA - 1);
 148
 149                 if(len == total) reply.more = more;
 150                 else reply.more = 1;
 151
 152                 memcpy(reply.data, str, len);
 153                 reply.data[len] = '\0';
 154                 total -= len;
 155                 str += len;
 156                 reply.len = len + 1;
 157
 158                 len = sizeof(reply) + reply.len - sizeof(reply.data);
 159
 160                 n = sendto(req->originating_fd, &reply, len, 0,
 161                            (struct sockaddr *) req->origin, req->originlen);
 162
 163                 if(n < 0) return(-errno);
 164         } while(total > 0);
 165         return(0);
 166 }
 167
 168 int mconsole_reply(struct mc_request *req, const char *str, int err, int more)
 169 {
 170         return mconsole_reply_len(req, str, strlen(str), err, more);
 171 }
 172
 173
 174 int mconsole_unlink_socket(void)
 175 {
 176         unlink(mconsole_socket_name);
 177         return 0;
 178 }
 179
 180 static int notify_sock = -1;
 181
 182 int mconsole_notify(char *sock_name, int type, const void *data, int len)
 183 {
 184         struct sockaddr_un target;
 185         struct mconsole_notify packet;
 186         int n, err = 0;
 187
 188         lock_notify();
 189         if(notify_sock < 0){
 190                 notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);
 191                 if(notify_sock < 0){
 192                         err = -errno;
 193                         printk("mconsole_notify - socket failed, errno = %d\n",
 194                                err);
 195                 }
 196         }
 197         unlock_notify();
 198
 199         if(err)
 200                 return(err);
 201
 202         target.sun_family = AF_UNIX;
 203         strcpy(target.sun_path, sock_name);
 204
 205         packet.magic = MCONSOLE_MAGIC;
 206         packet.version = MCONSOLE_VERSION;
 207         packet.type = type;
 208         len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;
 209         packet.len = len;
 210         memcpy(packet.data, data, len);
 211
 212         err = 0;
 213         len = sizeof(packet) + packet.len - sizeof(packet.data);
 214         n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,
 215                    sizeof(target));
 216         if(n < 0){
 217                 err = -errno;
 218                 printk("mconsole_notify - sendto failed, errno = %d\n", errno);
 219         }
 220         return(err);
 221 }
 222
 223 /*
 224  * Overrides for Emacs so that we follow Linus's tabbing style.
 225  * Emacs will notice this stuff at the end of the file and automatically
 226  * adjust the settings for this buffer only.  This must remain at the end
 227  * of the file.
 228  * ---------------------------------------------------------------------------
 229  * Local variables:
 230  * c-file-style: "linux"
 231  * End:
 232  */