linux/arch/um/drivers/mconsole_user.c
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   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 "mconsole.h"
  14
  15static 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 */
  38char mconsole_socket_name[256];
  39
  40static int mconsole_reply_v0(struct mc_request *req, char *reply)
  41{
  42        struct iovec iov;
  43        struct msghdr msg;
  44
  45        iov.iov_base = reply;
  46        iov.iov_len = strlen(reply);
  47
  48        msg.msg_name = &(req->origin);
  49        msg.msg_namelen = req->originlen;
  50        msg.msg_iov = &iov;
  51        msg.msg_iovlen = 1;
  52        msg.msg_control = NULL;
  53        msg.msg_controllen = 0;
  54        msg.msg_flags = 0;
  55
  56        return sendmsg(req->originating_fd, &msg, 0);
  57}
  58
  59static struct mconsole_command *mconsole_parse(struct mc_request *req)
  60{
  61        struct mconsole_command *cmd;
  62        int i;
  63
  64        for (i = 0; i < ARRAY_SIZE(commands); i++) {
  65                cmd = &commands[i];
  66                if (!strncmp(req->request.data, cmd->command,
  67                            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
  79int mconsole_get_request(int fd, struct mc_request *req)
  80{
  81        int len;
  82
  83        req->originlen = sizeof(req->origin);
  84        req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
  85                            (struct sockaddr *) req->origin, &req->originlen);
  86        if (req->len < 0)
  87                return 0;
  88
  89        req->originating_fd = fd;
  90
  91        if (req->request.magic != MCONSOLE_MAGIC) {
  92                /* Unversioned request */
  93                len = MIN(sizeof(req->request.data) - 1,
  94                          strlen((char *) &req->request));
  95                memmove(req->request.data, &req->request, len);
  96                req->request.data[len] = '\0';
  97
  98                req->request.magic = MCONSOLE_MAGIC;
  99                req->request.version = 0;
 100                req->request.len = len;
 101
 102                mconsole_reply_v0(req, "ERR Version 0 mconsole clients are "
 103                                  "not supported by this driver");
 104                return 0;
 105        }
 106
 107        if (req->request.len >= MCONSOLE_MAX_DATA) {
 108                mconsole_reply(req, "Request too large", 1, 0);
 109                return 0;
 110        }
 111        if (req->request.version != MCONSOLE_VERSION) {
 112                mconsole_reply(req, "This driver only supports version "
 113                               STRING(MCONSOLE_VERSION) " clients", 1, 0);
 114        }
 115
 116        req->request.data[req->request.len] = '\0';
 117        req->cmd = mconsole_parse(req);
 118        if (req->cmd == NULL) {
 119                mconsole_reply(req, "Unknown command", 1, 0);
 120                return 0;
 121        }
 122
 123        return 1;
 124}
 125
 126int 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                reply.err = err;
 139
 140                /* err can only be true on the first packet */
 141                err = 0;
 142
 143                len = MIN(total, MCONSOLE_MAX_DATA - 1);
 144
 145                if (len == total) reply.more = more;
 146                else reply.more = 1;
 147
 148                memcpy(reply.data, str, len);
 149                reply.data[len] = '\0';
 150                total -= len;
 151                str += len;
 152                reply.len = len + 1;
 153
 154                len = sizeof(reply) + reply.len - sizeof(reply.data);
 155
 156                n = sendto(req->originating_fd, &reply, len, 0,
 157                           (struct sockaddr *) req->origin, req->originlen);
 158
 159                if (n < 0)
 160                        return -errno;
 161        } while (total > 0);
 162        return 0;
 163}
 164
 165int mconsole_reply(struct mc_request *req, const char *str, int err, int more)
 166{
 167        return mconsole_reply_len(req, str, strlen(str), err, more);
 168}
 169
 170
 171int mconsole_unlink_socket(void)
 172{
 173        unlink(mconsole_socket_name);
 174        return 0;
 175}
 176
 177static int notify_sock = -1;
 178
 179int mconsole_notify(char *sock_name, int type, const void *data, int len)
 180{
 181        struct sockaddr_un target;
 182        struct mconsole_notify packet;
 183        int n, err = 0;
 184
 185        lock_notify();
 186        if (notify_sock < 0) {
 187                notify_sock = socket(PF_UNIX, SOCK_DGRAM, 0);
 188                if (notify_sock < 0) {
 189                        err = -errno;
 190                        printk(UM_KERN_ERR "mconsole_notify - socket failed, "
 191                               "errno = %d\n", errno);
 192                }
 193        }
 194        unlock_notify();
 195
 196        if (err)
 197                return err;
 198
 199        target.sun_family = AF_UNIX;
 200        strcpy(target.sun_path, sock_name);
 201
 202        packet.magic = MCONSOLE_MAGIC;
 203        packet.version = MCONSOLE_VERSION;
 204        packet.type = type;
 205        len = (len > sizeof(packet.data)) ? sizeof(packet.data) : len;
 206        packet.len = len;
 207        memcpy(packet.data, data, len);
 208
 209        err = 0;
 210        len = sizeof(packet) + packet.len - sizeof(packet.data);
 211        n = sendto(notify_sock, &packet, len, 0, (struct sockaddr *) &target,
 212                   sizeof(target));
 213        if (n < 0) {
 214                err = -errno;
 215                printk(UM_KERN_ERR "mconsole_notify - sendto failed, "
 216                       "errno = %d\n", errno);
 217        }
 218        return err;
 219}
 220
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