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 "umid.h"
  20 #include "user_util.h"
  21
  22 static struct mconsole_command commands[] = {
  23         /* With uts namespaces, uts information becomes process-specific, so
  24          * we need a process context.  If we try handling this in interrupt
  25          * context, we may hit an exiting process without a valid uts
  26          * namespace.
  27          */
  28         { "version", mconsole_version, MCONSOLE_PROC },
  29         { "halt", mconsole_halt, MCONSOLE_PROC },
  30         { "reboot", mconsole_reboot, MCONSOLE_PROC },
  31         { "config", mconsole_config, MCONSOLE_PROC },
  32         { "remove", mconsole_remove, MCONSOLE_PROC },
  33         { "sysrq", mconsole_sysrq, MCONSOLE_INTR },
  34         { "help", mconsole_help, MCONSOLE_INTR },
  35         { "cad", mconsole_cad, MCONSOLE_INTR },
  36         { "stop", mconsole_stop, MCONSOLE_PROC },
  37         { "go", mconsole_go, MCONSOLE_INTR },
  38         { "log", mconsole_log, MCONSOLE_INTR },
  39         { "proc", mconsole_proc, MCONSOLE_PROC },
  40         { "stack", mconsole_stack, MCONSOLE_INTR },
  41 };
  42
  43 /* Initialized in mconsole_init, which is an initcall */
  44 char mconsole_socket_name[256];
  45
  46 int mconsole_reply_v0(struct mc_request *req, char *reply)
  47 {
  48         struct iovec iov;
  49         struct msghdr msg;
  50
  51         iov.iov_base = reply;
  52         iov.iov_len = strlen(reply);
  53
  54         msg.msg_name = &(req->origin);
  55         msg.msg_namelen = req->originlen;
  56         msg.msg_iov = &iov;
  57         msg.msg_iovlen = 1;
  58         msg.msg_control = NULL;
  59         msg.msg_controllen = 0;
  60         msg.msg_flags = 0;
  61
  62         return sendmsg(req->originating_fd, &msg, 0);
  63 }
  64
  65 static struct mconsole_command *mconsole_parse(struct mc_request *req)
  66 {
  67         struct mconsole_command *cmd;
  68         int i;
  69
  70         for(i = 0; i < ARRAY_SIZE(commands); i++){
  71                 cmd = &commands[i];
  72                 if(!strncmp(req->request.data, cmd->command,
  73                             strlen(cmd->command))){
  74                         return cmd;
  75                 }
  76         }
  77         return NULL;
  78 }
  79
  80 #define MIN(a,b) ((a)<(b) ? (a):(b))
  81
  82 #define STRINGX(x) #x
  83 #define STRING(x) STRINGX(x)
  84
  85 int mconsole_get_request(int fd, struct mc_request *req)
  86 {
  87         int len;
  88
  89         req->originlen = sizeof(req->origin);
  90         req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
  91                             (struct sockaddr *) req->origin, &req->originlen);
  92         if (req->len < 0)
  93                 return 0;
  94
  95         req->originating_fd = fd;
  96
  97         if(req->request.magic != MCONSOLE_MAGIC){
  98                 /* Unversioned request */
  99                 len = MIN(sizeof(req->request.data) - 1,
 100                           strlen((char *) &req->request));
 101                 memmove(req->request.data, &req->request, len);
 102                 req->request.data[len] = '\0';
 103
 104                 req->request.magic = MCONSOLE_MAGIC;
 105                 req->request.version = 0;
 106                 req->request.len = len;
 107
 108                 mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "
 109                                   "not supported by this driver");
 110                 return(0);
 111         }
 112
 113         if(req->request.len >= MCONSOLE_MAX_DATA){
 114                 mconsole_reply(req, "Request too large", 1, 0);
 115                 return(0);
 116         }
 117         if(req->request.version != MCONSOLE_VERSION){
 118                 mconsole_reply(req, "This driver only supports version "
 119                                STRING(MCONSOLE_VERSION) " clients", 1, 0);
 120         }
 121
 122         req->request.data[req->request.len] = '\0';
 123         req->cmd = mconsole_parse(req);
 124         if(req->cmd == NULL){
 125                 mconsole_reply(req, "Unknown command", 1, 0);
 126                 return(0);
 127         }
 128
 129         return(1);
 130 }
 131
 132 int mconsole_reply_len(struct mc_request *req, const char *str, int total,
 133                        int err, int more)
 134 {
 135         /* XXX This is a stack consumption problem.  It'd be nice to
 136          * make it global and serialize access to it, but there are a
 137          * ton of callers to this function.
 138          */
 139         struct mconsole_reply reply;
 140         int len, n;
 141
 142         do {
 143                 reply.err = err;
 144
 145                 /* err can only be true on the first packet */
 146                 err = 0;
 147
 148                 len = MIN(total, MCONSOLE_MAX_DATA - 1);
 149
 150                 if(len == total) reply.more = more;
 151                 else reply.more = 1;
 152
 153                 memcpy(reply.data, str, len);
 154                 reply.data[len] = '\0';
 155                 total -= len;
 156                 str += len;
 157                 reply.len = len + 1;
 158
 159                 len = sizeof(reply) + reply.len - sizeof(reply.data);
 160
 161                 n = sendto(req->originating_fd, &reply, len, 0,
 162                            (struct sockaddr *) req->origin, req->originlen);
 163
 164                 if(n < 0) return(-errno);
 165         } while(total > 0);
 166         return(0);
 167 }
 168
 169 int mconsole_reply(struct mc_request *req, const char *str, int err, int more)
 170 {
 171         return mconsole_reply_len(req, str, strlen(str), err, more);
 172 }
 173
 174
 175 int mconsole_unlink_socket(void)
 176 {
 177         unlink(mconsole_socket_name);
 178         return 0;
 179 }
 180
 181 static int notify_sock = -1;
 182
 183 int mconsole_notify(char *sock_name, int type, const void *data, int len)
 184 {
 185         struct sockaddr_un target;
 186         struct mconsole_notify packet;
 187         int n, err = 0;
 188
 189         lock_notify();
 190         if(notify_sock < 0){
 191                 notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);
 192                 if(notify_sock < 0){
 193                         err = -errno;
 194                         printk("mconsole_notify - socket failed, errno = %d\n",
 195                                err);
 196                 }
 197         }
 198         unlock_notify();
 199
 200         if(err)
 201                 return(err);
 202
 203         target.sun_family = AF_UNIX;
 204         strcpy(target.sun_path, sock_name);
 205
 206         packet.magic = MCONSOLE_MAGIC;
 207         packet.version = MCONSOLE_VERSION;
 208         packet.type = type;
 209         len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;
 210         packet.len = len;
 211         memcpy(packet.data, data, len);
 212
 213         err = 0;
 214         len = sizeof(packet) + packet.len - sizeof(packet.data);
 215         n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,
 216                    sizeof(target));
 217         if(n < 0){
 218                 err = -errno;
 219                 printk("mconsole_notify - sendto failed, errno = %d\n", errno);
 220         }
 221         return(err);
 222 }
 223
 224 /*
 225  * Overrides for Emacs so that we follow Linus's tabbing style.
 226  * Emacs will notice this stuff at the end of the file and automatically
 227  * adjust the settings for this buffer only.  This must remain at the end
 228  * of the file.
 229  * ---------------------------------------------------------------------------
 230  * Local variables:
 231  * c-file-style: "linux"
 232  * End:
 233  */