cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

ivshmem-server.c (13501B)

      1/*
      2 * Copyright 6WIND S.A., 2014
      3 *
      4 * This work is licensed under the terms of the GNU GPL, version 2 or
      5 * (at your option) any later version.  See the COPYING file in the
      6 * top-level directory.
      7 */
      8#include "qemu/osdep.h"
      9#include "qemu/host-utils.h"
     10#include "qemu/sockets.h"
     11
     12#include <sys/socket.h>
     13#include <sys/un.h>
     14
     15#include "ivshmem-server.h"
     16
     17/* log a message on stdout if verbose=1 */
     18#define IVSHMEM_SERVER_DEBUG(server, fmt, ...) do { \
     19        if ((server)->verbose) {         \
     20            printf(fmt, ## __VA_ARGS__); \
     21        }                                \
     22    } while (0)
     23
     24/** maximum size of a huge page, used by ivshmem_server_ftruncate() */
     25#define IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE (1024 * 1024 * 1024)
     26
     27/** default listen backlog (number of sockets not accepted) */
     28#define IVSHMEM_SERVER_LISTEN_BACKLOG 10
     29
     30/* send message to a client unix socket */
     31static int
     32ivshmem_server_send_one_msg(int sock_fd, int64_t peer_id, int fd)
     33{
     34    int ret;
     35    struct msghdr msg;
     36    struct iovec iov[1];
     37    union {
     38        struct cmsghdr cmsg;
     39        char control[CMSG_SPACE(sizeof(int))];
     40    } msg_control;
     41    struct cmsghdr *cmsg;
     42
     43    peer_id = GINT64_TO_LE(peer_id);
     44    iov[0].iov_base = &peer_id;
     45    iov[0].iov_len = sizeof(peer_id);
     46
     47    memset(&msg, 0, sizeof(msg));
     48    msg.msg_iov = iov;
     49    msg.msg_iovlen = 1;
     50
     51    /* if fd is specified, add it in a cmsg */
     52    if (fd >= 0) {
     53        memset(&msg_control, 0, sizeof(msg_control));
     54        msg.msg_control = &msg_control;
     55        msg.msg_controllen = sizeof(msg_control);
     56        cmsg = CMSG_FIRSTHDR(&msg);
     57        cmsg->cmsg_level = SOL_SOCKET;
     58        cmsg->cmsg_type = SCM_RIGHTS;
     59        cmsg->cmsg_len = CMSG_LEN(sizeof(int));
     60        memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
     61    }
     62
     63    ret = sendmsg(sock_fd, &msg, 0);
     64    if (ret <= 0) {
     65        return -1;
     66    }
     67
     68    return 0;
     69}
     70
     71/* free a peer when the server advertises a disconnection or when the
     72 * server is freed */
     73static void
     74ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
     75{
     76    unsigned vector;
     77    IvshmemServerPeer *other_peer;
     78
     79    IVSHMEM_SERVER_DEBUG(server, "free peer %" PRId64 "\n", peer->id);
     80    close(peer->sock_fd);
     81    QTAILQ_REMOVE(&server->peer_list, peer, next);
     82
     83    /* advertise the deletion to other peers */
     84    QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
     85        ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id, -1);
     86    }
     87
     88    for (vector = 0; vector < peer->vectors_count; vector++) {
     89        event_notifier_cleanup(&peer->vectors[vector]);
     90    }
     91
     92    g_free(peer);
     93}
     94
     95/* send the peer id and the shm_fd just after a new client connection */
     96static int
     97ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
     98{
     99    int ret;
    100
    101    /* send our protocol version first */
    102    ret = ivshmem_server_send_one_msg(peer->sock_fd, IVSHMEM_PROTOCOL_VERSION,
    103                                      -1);
    104    if (ret < 0) {
    105        IVSHMEM_SERVER_DEBUG(server, "cannot send version: %s\n",
    106                             strerror(errno));
    107        return -1;
    108    }
    109
    110    /* send the peer id to the client */
    111    ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
    112    if (ret < 0) {
    113        IVSHMEM_SERVER_DEBUG(server, "cannot send peer id: %s\n",
    114                             strerror(errno));
    115        return -1;
    116    }
    117
    118    /* send the shm_fd */
    119    ret = ivshmem_server_send_one_msg(peer->sock_fd, -1, server->shm_fd);
    120    if (ret < 0) {
    121        IVSHMEM_SERVER_DEBUG(server, "cannot send shm fd: %s\n",
    122                             strerror(errno));
    123        return -1;
    124    }
    125
    126    return 0;
    127}
    128
    129/* handle message on listening unix socket (new client connection) */
    130static int
    131ivshmem_server_handle_new_conn(IvshmemServer *server)
    132{
    133    IvshmemServerPeer *peer, *other_peer;
    134    struct sockaddr_un unaddr;
    135    socklen_t unaddr_len;
    136    int newfd;
    137    unsigned i;
    138
    139    /* accept the incoming connection */
    140    unaddr_len = sizeof(unaddr);
    141    newfd = qemu_accept(server->sock_fd,
    142                        (struct sockaddr *)&unaddr, &unaddr_len);
    143
    144    if (newfd < 0) {
    145        IVSHMEM_SERVER_DEBUG(server, "cannot accept() %s\n", strerror(errno));
    146        return -1;
    147    }
    148
    149    qemu_set_nonblock(newfd);
    150    IVSHMEM_SERVER_DEBUG(server, "accept()=%d\n", newfd);
    151
    152    /* allocate new structure for this peer */
    153    peer = g_malloc0(sizeof(*peer));
    154    peer->sock_fd = newfd;
    155
    156    /* get an unused peer id */
    157    /* XXX: this could use id allocation such as Linux IDA, or simply
    158     * a free-list */
    159    for (i = 0; i < G_MAXUINT16; i++) {
    160        if (ivshmem_server_search_peer(server, server->cur_id) == NULL) {
    161            break;
    162        }
    163        server->cur_id++;
    164    }
    165    if (i == G_MAXUINT16) {
    166        IVSHMEM_SERVER_DEBUG(server, "cannot allocate new client id\n");
    167        close(newfd);
    168        g_free(peer);
    169        return -1;
    170    }
    171    peer->id = server->cur_id++;
    172
    173    /* create eventfd, one per vector */
    174    peer->vectors_count = server->n_vectors;
    175    for (i = 0; i < peer->vectors_count; i++) {
    176        if (event_notifier_init(&peer->vectors[i], FALSE) < 0) {
    177            IVSHMEM_SERVER_DEBUG(server, "cannot create eventfd\n");
    178            goto fail;
    179        }
    180    }
    181
    182    /* send peer id and shm fd */
    183    if (ivshmem_server_send_initial_info(server, peer) < 0) {
    184        IVSHMEM_SERVER_DEBUG(server, "cannot send initial info\n");
    185        goto fail;
    186    }
    187
    188    /* advertise the new peer to others */
    189    QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
    190        for (i = 0; i < peer->vectors_count; i++) {
    191            ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id,
    192                                        peer->vectors[i].wfd);
    193        }
    194    }
    195
    196    /* advertise the other peers to the new one */
    197    QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
    198        for (i = 0; i < peer->vectors_count; i++) {
    199            ivshmem_server_send_one_msg(peer->sock_fd, other_peer->id,
    200                                        other_peer->vectors[i].wfd);
    201        }
    202    }
    203
    204    /* advertise the new peer to itself */
    205    for (i = 0; i < peer->vectors_count; i++) {
    206        ivshmem_server_send_one_msg(peer->sock_fd, peer->id,
    207                                    event_notifier_get_fd(&peer->vectors[i]));
    208    }
    209
    210    QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
    211    IVSHMEM_SERVER_DEBUG(server, "new peer id = %" PRId64 "\n",
    212                         peer->id);
    213    return 0;
    214
    215fail:
    216    while (i--) {
    217        event_notifier_cleanup(&peer->vectors[i]);
    218    }
    219    close(newfd);
    220    g_free(peer);
    221    return -1;
    222}
    223
    224/* Try to ftruncate a file to next power of 2 of shmsize.
    225 * If it fails; all power of 2 above shmsize are tested until
    226 * we reach the maximum huge page size. This is useful
    227 * if the shm file is in a hugetlbfs that cannot be truncated to the
    228 * shm_size value. */
    229static int
    230ivshmem_server_ftruncate(int fd, unsigned shmsize)
    231{
    232    int ret;
    233    struct stat mapstat;
    234
    235    /* align shmsize to next power of 2 */
    236    shmsize = pow2ceil(shmsize);
    237
    238    if (fstat(fd, &mapstat) != -1 && mapstat.st_size == shmsize) {
    239        return 0;
    240    }
    241
    242    while (shmsize <= IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE) {
    243        ret = ftruncate(fd, shmsize);
    244        if (ret == 0) {
    245            return ret;
    246        }
    247        shmsize *= 2;
    248    }
    249
    250    return -1;
    251}
    252
    253/* Init a new ivshmem server */
    254int
    255ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
    256                    const char *shm_path, bool use_shm_open,
    257                    size_t shm_size, unsigned n_vectors,
    258                    bool verbose)
    259{
    260    int ret;
    261
    262    memset(server, 0, sizeof(*server));
    263    server->verbose = verbose;
    264
    265    ret = snprintf(server->unix_sock_path, sizeof(server->unix_sock_path),
    266                   "%s", unix_sock_path);
    267    if (ret < 0 || ret >= sizeof(server->unix_sock_path)) {
    268        IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
    269        return -1;
    270    }
    271    ret = snprintf(server->shm_path, sizeof(server->shm_path),
    272                   "%s", shm_path);
    273    if (ret < 0 || ret >= sizeof(server->shm_path)) {
    274        IVSHMEM_SERVER_DEBUG(server, "could not copy shm path\n");
    275        return -1;
    276    }
    277
    278    server->use_shm_open = use_shm_open;
    279    server->shm_size = shm_size;
    280    server->n_vectors = n_vectors;
    281
    282    QTAILQ_INIT(&server->peer_list);
    283
    284    return 0;
    285}
    286
    287/* open shm, create and bind to the unix socket */
    288int
    289ivshmem_server_start(IvshmemServer *server)
    290{
    291    struct sockaddr_un s_un;
    292    int shm_fd, sock_fd, ret;
    293
    294    /* open shm file */
    295    if (server->use_shm_open) {
    296        IVSHMEM_SERVER_DEBUG(server, "Using POSIX shared memory: %s\n",
    297                             server->shm_path);
    298        shm_fd = shm_open(server->shm_path, O_CREAT | O_RDWR, S_IRWXU);
    299    } else {
    300        gchar *filename = g_strdup_printf("%s/ivshmem.XXXXXX", server->shm_path);
    301        IVSHMEM_SERVER_DEBUG(server, "Using file-backed shared memory: %s\n",
    302                             server->shm_path);
    303        shm_fd = mkstemp(filename);
    304        unlink(filename);
    305        g_free(filename);
    306    }
    307
    308    if (shm_fd < 0) {
    309        fprintf(stderr, "cannot open shm file %s: %s\n", server->shm_path,
    310                strerror(errno));
    311        return -1;
    312    }
    313    if (ivshmem_server_ftruncate(shm_fd, server->shm_size) < 0) {
    314        fprintf(stderr, "ftruncate(%s) failed: %s\n", server->shm_path,
    315                strerror(errno));
    316        goto err_close_shm;
    317    }
    318
    319    IVSHMEM_SERVER_DEBUG(server, "create & bind socket %s\n",
    320                         server->unix_sock_path);
    321
    322    /* create the unix listening socket */
    323    sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
    324    if (sock_fd < 0) {
    325        IVSHMEM_SERVER_DEBUG(server, "cannot create socket: %s\n",
    326                             strerror(errno));
    327        goto err_close_shm;
    328    }
    329
    330    s_un.sun_family = AF_UNIX;
    331    ret = snprintf(s_un.sun_path, sizeof(s_un.sun_path), "%s",
    332                   server->unix_sock_path);
    333    if (ret < 0 || ret >= sizeof(s_un.sun_path)) {
    334        IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
    335        goto err_close_sock;
    336    }
    337    if (bind(sock_fd, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) {
    338        IVSHMEM_SERVER_DEBUG(server, "cannot connect to %s: %s\n", s_un.sun_path,
    339                             strerror(errno));
    340        goto err_close_sock;
    341    }
    342
    343    if (listen(sock_fd, IVSHMEM_SERVER_LISTEN_BACKLOG) < 0) {
    344        IVSHMEM_SERVER_DEBUG(server, "listen() failed: %s\n", strerror(errno));
    345        goto err_close_sock;
    346    }
    347
    348    server->sock_fd = sock_fd;
    349    server->shm_fd = shm_fd;
    350
    351    return 0;
    352
    353err_close_sock:
    354    close(sock_fd);
    355err_close_shm:
    356    if (server->use_shm_open) {
    357        shm_unlink(server->shm_path);
    358    }
    359    close(shm_fd);
    360    return -1;
    361}
    362
    363/* close connections to clients, the unix socket and the shm fd */
    364void
    365ivshmem_server_close(IvshmemServer *server)
    366{
    367    IvshmemServerPeer *peer, *npeer;
    368
    369    IVSHMEM_SERVER_DEBUG(server, "close server\n");
    370
    371    QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, npeer) {
    372        ivshmem_server_free_peer(server, peer);
    373    }
    374
    375    unlink(server->unix_sock_path);
    376    if (server->use_shm_open) {
    377        shm_unlink(server->shm_path);
    378    }
    379    close(server->sock_fd);
    380    close(server->shm_fd);
    381    server->sock_fd = -1;
    382    server->shm_fd = -1;
    383}
    384
    385/* get the fd_set according to the unix socket and the peer list */
    386void
    387ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd)
    388{
    389    IvshmemServerPeer *peer;
    390
    391    if (server->sock_fd == -1) {
    392        return;
    393    }
    394
    395    FD_SET(server->sock_fd, fds);
    396    if (server->sock_fd >= *maxfd) {
    397        *maxfd = server->sock_fd + 1;
    398    }
    399
    400    QTAILQ_FOREACH(peer, &server->peer_list, next) {
    401        FD_SET(peer->sock_fd, fds);
    402        if (peer->sock_fd >= *maxfd) {
    403            *maxfd = peer->sock_fd + 1;
    404        }
    405    }
    406}
    407
    408/* process incoming messages on the sockets in fd_set */
    409int
    410ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
    411{
    412    IvshmemServerPeer *peer, *peer_next;
    413
    414    if (server->sock_fd < maxfd && FD_ISSET(server->sock_fd, fds) &&
    415        ivshmem_server_handle_new_conn(server) < 0 && errno != EINTR) {
    416        IVSHMEM_SERVER_DEBUG(server, "ivshmem_server_handle_new_conn() "
    417                             "failed\n");
    418        return -1;
    419    }
    420
    421    QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, peer_next) {
    422        /* any message from a peer socket result in a close() */
    423        IVSHMEM_SERVER_DEBUG(server, "peer->sock_fd=%d\n", peer->sock_fd);
    424        if (peer->sock_fd < maxfd && FD_ISSET(peer->sock_fd, fds)) {
    425            ivshmem_server_free_peer(server, peer);
    426        }
    427    }
    428
    429    return 0;
    430}
    431
    432/* lookup peer from its id */
    433IvshmemServerPeer *
    434ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id)
    435{
    436    IvshmemServerPeer *peer;
    437
    438    QTAILQ_FOREACH(peer, &server->peer_list, next) {
    439        if (peer->id == peer_id) {
    440            return peer;
    441        }
    442    }
    443    return NULL;
    444}
    445
    446/* dump our info, the list of peers their vectors on stdout */
    447void
    448ivshmem_server_dump(const IvshmemServer *server)
    449{
    450    const IvshmemServerPeer *peer;
    451    unsigned vector;
    452
    453    /* dump peers */
    454    QTAILQ_FOREACH(peer, &server->peer_list, next) {
    455        printf("peer_id = %" PRId64 "\n", peer->id);
    456
    457        for (vector = 0; vector < peer->vectors_count; vector++) {
    458            printf("  vector %d is enabled (fd=%d)\n", vector,
    459                   event_notifier_get_fd(&peer->vectors[vector]));
    460        }
    461    }
    462}