qemu/scsi/qemu-pr-helper.c
<<
>>
Prefs
   1/*
   2 * Privileged helper to handle persistent reservation commands for QEMU
   3 *
   4 * Copyright (C) 2017 Red Hat, Inc. <pbonzini@redhat.com>
   5 *
   6 * Author: Paolo Bonzini <pbonzini@redhat.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; under version 2 of the License.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21#include "qemu/osdep.h"
  22#include <getopt.h>
  23#include <sys/ioctl.h>
  24#include <linux/dm-ioctl.h>
  25#include <scsi/sg.h>
  26
  27#ifdef CONFIG_LIBCAP
  28#include <cap-ng.h>
  29#endif
  30#include <pwd.h>
  31#include <grp.h>
  32
  33#ifdef CONFIG_MPATH
  34#include <libudev.h>
  35#include <mpath_cmd.h>
  36#include <mpath_persist.h>
  37#endif
  38
  39#include "qemu-common.h"
  40#include "qapi/error.h"
  41#include "qemu/cutils.h"
  42#include "qemu/main-loop.h"
  43#include "qemu/module.h"
  44#include "qemu/error-report.h"
  45#include "qemu/config-file.h"
  46#include "qemu/bswap.h"
  47#include "qemu/log.h"
  48#include "qemu/systemd.h"
  49#include "qapi/util.h"
  50#include "qapi/qmp/qstring.h"
  51#include "io/channel-socket.h"
  52#include "trace/control.h"
  53#include "qemu-version.h"
  54
  55#include "block/aio.h"
  56#include "block/thread-pool.h"
  57
  58#include "scsi/constants.h"
  59#include "scsi/utils.h"
  60#include "pr-helper.h"
  61
  62#define PR_OUT_FIXED_PARAM_SIZE 24
  63
  64static char *socket_path;
  65static char *pidfile;
  66static enum { RUNNING, TERMINATE, TERMINATING } state;
  67static QIOChannelSocket *server_ioc;
  68static int server_watch;
  69static int num_active_sockets = 1;
  70static int noisy;
  71static int verbose;
  72
  73#ifdef CONFIG_LIBCAP
  74static int uid = -1;
  75static int gid = -1;
  76#endif
  77
  78static void compute_default_paths(void)
  79{
  80    socket_path = qemu_get_local_state_pathname("run/qemu-pr-helper.sock");
  81    pidfile = qemu_get_local_state_pathname("run/qemu-pr-helper.pid");
  82}
  83
  84static void usage(const char *name)
  85{
  86    (printf) (
  87"Usage: %s [OPTIONS] FILE\n"
  88"Persistent Reservation helper program for QEMU\n"
  89"\n"
  90"  -h, --help                display this help and exit\n"
  91"  -V, --version             output version information and exit\n"
  92"\n"
  93"  -d, --daemon              run in the background\n"
  94"  -f, --pidfile=PATH        PID file when running as a daemon\n"
  95"                            (default '%s')\n"
  96"  -k, --socket=PATH         path to the unix socket\n"
  97"                            (default '%s')\n"
  98"  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
  99"                            specify tracing options\n"
 100#ifdef CONFIG_LIBCAP
 101"  -u, --user=USER           user to drop privileges to\n"
 102"  -g, --group=GROUP         group to drop privileges to\n"
 103#endif
 104"\n"
 105QEMU_HELP_BOTTOM "\n"
 106    , name, pidfile, socket_path);
 107}
 108
 109static void version(const char *name)
 110{
 111    printf(
 112"%s " QEMU_FULL_VERSION "\n"
 113"Written by Paolo Bonzini.\n"
 114"\n"
 115QEMU_COPYRIGHT "\n"
 116"This is free software; see the source for copying conditions.  There is NO\n"
 117"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 118    , name);
 119}
 120
 121/* SG_IO support */
 122
 123typedef struct PRHelperSGIOData {
 124    int fd;
 125    const uint8_t *cdb;
 126    uint8_t *sense;
 127    uint8_t *buf;
 128    int sz;              /* input/output */
 129    int dir;
 130} PRHelperSGIOData;
 131
 132static int do_sgio_worker(void *opaque)
 133{
 134    PRHelperSGIOData *data = opaque;
 135    struct sg_io_hdr io_hdr;
 136    int ret;
 137    int status;
 138    SCSISense sense_code;
 139
 140    memset(data->sense, 0, PR_HELPER_SENSE_SIZE);
 141    memset(&io_hdr, 0, sizeof(io_hdr));
 142    io_hdr.interface_id = 'S';
 143    io_hdr.cmd_len = PR_HELPER_CDB_SIZE;
 144    io_hdr.cmdp = (uint8_t *)data->cdb;
 145    io_hdr.sbp = data->sense;
 146    io_hdr.mx_sb_len = PR_HELPER_SENSE_SIZE;
 147    io_hdr.timeout = 1;
 148    io_hdr.dxfer_direction = data->dir;
 149    io_hdr.dxferp = (char *)data->buf;
 150    io_hdr.dxfer_len = data->sz;
 151    ret = ioctl(data->fd, SG_IO, &io_hdr);
 152    status = sg_io_sense_from_errno(ret < 0 ? errno : 0, &io_hdr,
 153                                    &sense_code);
 154    if (status == GOOD) {
 155        data->sz -= io_hdr.resid;
 156    } else {
 157        data->sz = 0;
 158    }
 159
 160    if (status == CHECK_CONDITION &&
 161        !(io_hdr.driver_status & SG_ERR_DRIVER_SENSE)) {
 162        scsi_build_sense(data->sense, sense_code);
 163    }
 164
 165    return status;
 166}
 167
 168static int do_sgio(int fd, const uint8_t *cdb, uint8_t *sense,
 169                    uint8_t *buf, int *sz, int dir)
 170{
 171    ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
 172    int r;
 173
 174    PRHelperSGIOData data = {
 175        .fd = fd,
 176        .cdb = cdb,
 177        .sense = sense,
 178        .buf = buf,
 179        .sz = *sz,
 180        .dir = dir,
 181    };
 182
 183    r = thread_pool_submit_co(pool, do_sgio_worker, &data);
 184    *sz = data.sz;
 185    return r;
 186}
 187
 188/* Device mapper interface */
 189
 190#ifdef CONFIG_MPATH
 191#define CONTROL_PATH "/dev/mapper/control"
 192
 193typedef struct DMData {
 194    struct dm_ioctl dm;
 195    uint8_t data[1024];
 196} DMData;
 197
 198static int control_fd;
 199
 200static void *dm_ioctl(int ioc, struct dm_ioctl *dm)
 201{
 202    static DMData d;
 203    memcpy(&d.dm, dm, sizeof(d.dm));
 204    QEMU_BUILD_BUG_ON(sizeof(d.data) < sizeof(struct dm_target_spec));
 205
 206    d.dm.version[0] = DM_VERSION_MAJOR;
 207    d.dm.version[1] = 0;
 208    d.dm.version[2] = 0;
 209    d.dm.data_size = 1024;
 210    d.dm.data_start = offsetof(DMData, data);
 211    if (ioctl(control_fd, ioc, &d) < 0) {
 212        return NULL;
 213    }
 214    memcpy(dm, &d.dm, sizeof(d.dm));
 215    return &d.data;
 216}
 217
 218static void *dm_dev_ioctl(int fd, int ioc, struct dm_ioctl *dm)
 219{
 220    struct stat st;
 221    int r;
 222
 223    r = fstat(fd, &st);
 224    if (r < 0) {
 225        perror("fstat");
 226        exit(1);
 227    }
 228
 229    dm->dev = st.st_rdev;
 230    return dm_ioctl(ioc, dm);
 231}
 232
 233static void dm_init(void)
 234{
 235    control_fd = open(CONTROL_PATH, O_RDWR);
 236    if (control_fd < 0) {
 237        perror("Cannot open " CONTROL_PATH);
 238        exit(1);
 239    }
 240    struct dm_ioctl dm = { };
 241    if (!dm_ioctl(DM_VERSION, &dm)) {
 242        perror("ioctl");
 243        exit(1);
 244    }
 245    if (dm.version[0] != DM_VERSION_MAJOR) {
 246        fprintf(stderr, "Unsupported device mapper interface");
 247        exit(1);
 248    }
 249}
 250
 251/* Variables required by libmultipath and libmpathpersist.  */
 252QEMU_BUILD_BUG_ON(PR_HELPER_DATA_SIZE > MPATH_MAX_PARAM_LEN);
 253static struct config *multipath_conf;
 254unsigned mpath_mx_alloc_len = PR_HELPER_DATA_SIZE;
 255int logsink;
 256struct udev *udev;
 257
 258extern struct config *get_multipath_config(void);
 259struct config *get_multipath_config(void)
 260{
 261    return multipath_conf;
 262}
 263
 264extern void put_multipath_config(struct config *conf);
 265void put_multipath_config(struct config *conf)
 266{
 267}
 268
 269static void multipath_pr_init(void)
 270{
 271    udev = udev_new();
 272#ifdef CONFIG_MPATH_NEW_API
 273    multipath_conf = mpath_lib_init();
 274#else
 275    mpath_lib_init(udev);
 276#endif
 277}
 278
 279static int is_mpath(int fd)
 280{
 281    struct dm_ioctl dm = { .flags = DM_NOFLUSH_FLAG };
 282    struct dm_target_spec *tgt;
 283
 284    tgt = dm_dev_ioctl(fd, DM_TABLE_STATUS, &dm);
 285    if (!tgt) {
 286        if (errno == ENXIO) {
 287            return 0;
 288        }
 289        perror("ioctl");
 290        exit(EXIT_FAILURE);
 291    }
 292    return !strncmp(tgt->target_type, "multipath", DM_MAX_TYPE_NAME);
 293}
 294
 295static SCSISense mpath_generic_sense(int r)
 296{
 297    switch (r) {
 298    case MPATH_PR_SENSE_NOT_READY:
 299         return SENSE_CODE(NOT_READY);
 300    case MPATH_PR_SENSE_MEDIUM_ERROR:
 301         return SENSE_CODE(READ_ERROR);
 302    case MPATH_PR_SENSE_HARDWARE_ERROR:
 303         return SENSE_CODE(TARGET_FAILURE);
 304    case MPATH_PR_SENSE_ABORTED_COMMAND:
 305         return SENSE_CODE(IO_ERROR);
 306    default:
 307         abort();
 308    }
 309}
 310
 311static int mpath_reconstruct_sense(int fd, int r, uint8_t *sense)
 312{
 313    switch (r) {
 314    case MPATH_PR_SUCCESS:
 315        return GOOD;
 316    case MPATH_PR_SENSE_NOT_READY:
 317    case MPATH_PR_SENSE_MEDIUM_ERROR:
 318    case MPATH_PR_SENSE_HARDWARE_ERROR:
 319    case MPATH_PR_SENSE_ABORTED_COMMAND:
 320        {
 321            /* libmpathpersist ate the exact sense.  Try to find it by
 322             * issuing TEST UNIT READY.
 323             */
 324            uint8_t cdb[6] = { TEST_UNIT_READY };
 325            int sz = 0;
 326            int ret = do_sgio(fd, cdb, sense, NULL, &sz, SG_DXFER_NONE);
 327
 328            if (ret != GOOD) {
 329                return ret;
 330            }
 331            scsi_build_sense(sense, mpath_generic_sense(r));
 332            return CHECK_CONDITION;
 333        }
 334
 335    case MPATH_PR_SENSE_UNIT_ATTENTION:
 336        /* Congratulations libmpathpersist, you ruined the Unit Attention...
 337         * Return a heavyweight one.
 338         */
 339        scsi_build_sense(sense, SENSE_CODE(SCSI_BUS_RESET));
 340        return CHECK_CONDITION;
 341    case MPATH_PR_SENSE_INVALID_OP:
 342        /* Only one valid sense.  */
 343        scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 344        return CHECK_CONDITION;
 345    case MPATH_PR_ILLEGAL_REQ:
 346        /* Guess.  */
 347        scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 348        return CHECK_CONDITION;
 349    case MPATH_PR_NO_SENSE:
 350        scsi_build_sense(sense, SENSE_CODE(NO_SENSE));
 351        return CHECK_CONDITION;
 352
 353    case MPATH_PR_RESERV_CONFLICT:
 354        return RESERVATION_CONFLICT;
 355
 356    case MPATH_PR_OTHER:
 357    default:
 358        scsi_build_sense(sense, SENSE_CODE(LUN_COMM_FAILURE));
 359        return CHECK_CONDITION;
 360    }
 361}
 362
 363static int multipath_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 364                           uint8_t *data, int sz)
 365{
 366    int rq_servact = cdb[1];
 367    struct prin_resp resp;
 368    size_t written;
 369    int r;
 370
 371    switch (rq_servact) {
 372    case MPATH_PRIN_RKEY_SA:
 373    case MPATH_PRIN_RRES_SA:
 374    case MPATH_PRIN_RCAP_SA:
 375        break;
 376    case MPATH_PRIN_RFSTAT_SA:
 377        /* Nobody implements it anyway, so bail out. */
 378    default:
 379        /* Cannot parse any other output.  */
 380        scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
 381        return CHECK_CONDITION;
 382    }
 383
 384    r = mpath_persistent_reserve_in(fd, rq_servact, &resp, noisy, verbose);
 385    if (r == MPATH_PR_SUCCESS) {
 386        switch (rq_servact) {
 387        case MPATH_PRIN_RKEY_SA:
 388        case MPATH_PRIN_RRES_SA: {
 389            struct prin_readdescr *out = &resp.prin_descriptor.prin_readkeys;
 390            assert(sz >= 8);
 391            written = MIN(out->additional_length + 8, sz);
 392            stl_be_p(&data[0], out->prgeneration);
 393            stl_be_p(&data[4], out->additional_length);
 394            memcpy(&data[8], out->key_list, written - 8);
 395            break;
 396        }
 397        case MPATH_PRIN_RCAP_SA: {
 398            struct prin_capdescr *out = &resp.prin_descriptor.prin_readcap;
 399            assert(sz >= 6);
 400            written = 6;
 401            stw_be_p(&data[0], out->length);
 402            data[2] = out->flags[0];
 403            data[3] = out->flags[1];
 404            stw_be_p(&data[4], out->pr_type_mask);
 405            break;
 406        }
 407        default:
 408            scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 409            return CHECK_CONDITION;
 410        }
 411        assert(written <= sz);
 412        memset(data + written, 0, sz - written);
 413    }
 414
 415    return mpath_reconstruct_sense(fd, r, sense);
 416}
 417
 418static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
 419                            const uint8_t *param, int sz)
 420{
 421    int rq_servact = cdb[1];
 422    int rq_scope = cdb[2] >> 4;
 423    int rq_type = cdb[2] & 0xf;
 424    g_autofree struct prout_param_descriptor *paramp = NULL;
 425    char transportids[PR_HELPER_DATA_SIZE];
 426    int r;
 427
 428    paramp = g_malloc0(sizeof(struct prout_param_descriptor)
 429                       + sizeof(struct transportid *) * MPATH_MX_TIDS);
 430
 431    if (sz < PR_OUT_FIXED_PARAM_SIZE) {
 432        /* Illegal request, Parameter list length error.  This isn't fatal;
 433         * we have read the data, send an error without closing the socket.
 434         */
 435        scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
 436        return CHECK_CONDITION;
 437    }
 438
 439    switch (rq_servact) {
 440    case MPATH_PROUT_REG_SA:
 441    case MPATH_PROUT_RES_SA:
 442    case MPATH_PROUT_REL_SA:
 443    case MPATH_PROUT_CLEAR_SA:
 444    case MPATH_PROUT_PREE_SA:
 445    case MPATH_PROUT_PREE_AB_SA:
 446    case MPATH_PROUT_REG_IGN_SA:
 447        break;
 448    case MPATH_PROUT_REG_MOV_SA:
 449        /* Not supported by struct prout_param_descriptor.  */
 450    default:
 451        /* Cannot parse any other input.  */
 452        scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
 453        return CHECK_CONDITION;
 454    }
 455
 456    /* Convert input data, especially transport IDs, to the structs
 457     * used by libmpathpersist (which, of course, will immediately
 458     * do the opposite).
 459     */
 460    memcpy(&paramp->key, &param[0], 8);
 461    memcpy(&paramp->sa_key, &param[8], 8);
 462    paramp->sa_flags = param[20];
 463    if (sz > PR_OUT_FIXED_PARAM_SIZE) {
 464        size_t transportid_len;
 465        int i, j;
 466        if (sz < PR_OUT_FIXED_PARAM_SIZE + 4) {
 467            scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
 468            return CHECK_CONDITION;
 469        }
 470        transportid_len = ldl_be_p(&param[24]) + PR_OUT_FIXED_PARAM_SIZE + 4;
 471        if (transportid_len > sz) {
 472            scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 473            return CHECK_CONDITION;
 474        }
 475        for (i = PR_OUT_FIXED_PARAM_SIZE + 4, j = 0; i < transportid_len; ) {
 476            struct transportid *id = (struct transportid *) &transportids[j];
 477            int len;
 478
 479            id->format_code = param[i] & 0xc0;
 480            id->protocol_id = param[i] & 0x0f;
 481            switch (param[i] & 0xcf) {
 482            case 0:
 483                /* FC transport.  */
 484                if (i + 24 > transportid_len) {
 485                    goto illegal_req;
 486                }
 487                memcpy(id->n_port_name, &param[i + 8], 8);
 488                j += offsetof(struct transportid, n_port_name[8]);
 489                i += 24;
 490                break;
 491            case 5:
 492            case 0x45:
 493                /* iSCSI transport.  */
 494                len = lduw_be_p(&param[i + 2]);
 495                if (len > 252 || (len & 3) || i + len + 4 > transportid_len) {
 496                    /* For format code 00, the standard says the maximum is 223
 497                     * plus the NUL terminator.  For format code 01 there is no
 498                     * maximum length, but libmpathpersist ignores the first
 499                     * byte of id->iscsi_name so our maximum is 252.
 500                     */
 501                    goto illegal_req;
 502                }
 503                if (memchr(&param[i + 4], 0, len) == NULL) {
 504                    goto illegal_req;
 505                }
 506                memcpy(id->iscsi_name, &param[i + 2], len + 2);
 507                j += offsetof(struct transportid, iscsi_name[len + 2]);
 508                i += len + 4;
 509                break;
 510            case 6:
 511                /* SAS transport.  */
 512                if (i + 24 > transportid_len) {
 513                    goto illegal_req;
 514                }
 515                memcpy(id->sas_address, &param[i + 4], 8);
 516                j += offsetof(struct transportid, sas_address[8]);
 517                i += 24;
 518                break;
 519            default:
 520            illegal_req:
 521                scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 522                return CHECK_CONDITION;
 523            }
 524
 525            assert(paramp->num_transportid < MPATH_MX_TIDS);
 526            paramp->trnptid_list[paramp->num_transportid++] = id;
 527        }
 528    }
 529
 530    r = mpath_persistent_reserve_out(fd, rq_servact, rq_scope, rq_type,
 531                                     paramp, noisy, verbose);
 532    return mpath_reconstruct_sense(fd, r, sense);
 533}
 534#endif
 535
 536static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 537                    uint8_t *data, int *resp_sz)
 538{
 539#ifdef CONFIG_MPATH
 540    if (is_mpath(fd)) {
 541        /* multipath_pr_in fills the whole input buffer.  */
 542        int r = multipath_pr_in(fd, cdb, sense, data, *resp_sz);
 543        if (r != GOOD) {
 544            *resp_sz = 0;
 545        }
 546        return r;
 547    }
 548#endif
 549
 550    return do_sgio(fd, cdb, sense, data, resp_sz,
 551                   SG_DXFER_FROM_DEV);
 552}
 553
 554static int do_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
 555                     const uint8_t *param, int sz)
 556{
 557    int resp_sz;
 558
 559    if ((fcntl(fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
 560        scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 561        return CHECK_CONDITION;
 562    }
 563
 564#ifdef CONFIG_MPATH
 565    if (is_mpath(fd)) {
 566        return multipath_pr_out(fd, cdb, sense, param, sz);
 567    }
 568#endif
 569
 570    resp_sz = sz;
 571    return do_sgio(fd, cdb, sense, (uint8_t *)param, &resp_sz,
 572                   SG_DXFER_TO_DEV);
 573}
 574
 575/* Client */
 576
 577typedef struct PRHelperClient {
 578    QIOChannelSocket *ioc;
 579    Coroutine *co;
 580    int fd;
 581    uint8_t data[PR_HELPER_DATA_SIZE];
 582} PRHelperClient;
 583
 584typedef struct PRHelperRequest {
 585    int fd;
 586    size_t sz;
 587    uint8_t cdb[PR_HELPER_CDB_SIZE];
 588} PRHelperRequest;
 589
 590static int coroutine_fn prh_read(PRHelperClient *client, void *buf, int sz,
 591                                 Error **errp)
 592{
 593    int ret = 0;
 594
 595    while (sz > 0) {
 596        int *fds = NULL;
 597        size_t nfds = 0;
 598        int i;
 599        struct iovec iov;
 600        ssize_t n_read;
 601
 602        iov.iov_base = buf;
 603        iov.iov_len = sz;
 604        n_read = qio_channel_readv_full(QIO_CHANNEL(client->ioc), &iov, 1,
 605                                        &fds, &nfds, errp);
 606
 607        if (n_read == QIO_CHANNEL_ERR_BLOCK) {
 608            qio_channel_yield(QIO_CHANNEL(client->ioc), G_IO_IN);
 609            continue;
 610        }
 611        if (n_read <= 0) {
 612            ret = n_read ? n_read : -1;
 613            goto err;
 614        }
 615
 616        /* Stash one file descriptor per request.  */
 617        if (nfds) {
 618            bool too_many = false;
 619            for (i = 0; i < nfds; i++) {
 620                if (client->fd == -1) {
 621                    client->fd = fds[i];
 622                } else {
 623                    close(fds[i]);
 624                    too_many = true;
 625                }
 626            }
 627            g_free(fds);
 628            if (too_many) {
 629                ret = -1;
 630                goto err;
 631            }
 632        }
 633
 634        buf += n_read;
 635        sz -= n_read;
 636    }
 637
 638    return 0;
 639
 640err:
 641    if (client->fd != -1) {
 642        close(client->fd);
 643        client->fd = -1;
 644    }
 645    return ret;
 646}
 647
 648static int coroutine_fn prh_read_request(PRHelperClient *client,
 649                                         PRHelperRequest *req,
 650                                         PRHelperResponse *resp, Error **errp)
 651{
 652    uint32_t sz;
 653
 654    if (prh_read(client, req->cdb, sizeof(req->cdb), NULL) < 0) {
 655        return -1;
 656    }
 657
 658    if (client->fd == -1) {
 659        error_setg(errp, "No file descriptor in request.");
 660        return -1;
 661    }
 662
 663    if (req->cdb[0] != PERSISTENT_RESERVE_OUT &&
 664        req->cdb[0] != PERSISTENT_RESERVE_IN) {
 665        error_setg(errp, "Invalid CDB, closing socket.");
 666        goto out_close;
 667    }
 668
 669    sz = scsi_cdb_xfer(req->cdb);
 670    if (sz > sizeof(client->data)) {
 671        goto out_close;
 672    }
 673
 674    if (req->cdb[0] == PERSISTENT_RESERVE_OUT) {
 675        if (qio_channel_read_all(QIO_CHANNEL(client->ioc),
 676                                 (char *)client->data, sz,
 677                                 errp) < 0) {
 678            goto out_close;
 679        }
 680    }
 681
 682    req->fd = client->fd;
 683    req->sz = sz;
 684    client->fd = -1;
 685    return sz;
 686
 687out_close:
 688    close(client->fd);
 689    client->fd = -1;
 690    return -1;
 691}
 692
 693static int coroutine_fn prh_write_response(PRHelperClient *client,
 694                                           PRHelperRequest *req,
 695                                           PRHelperResponse *resp, Error **errp)
 696{
 697    ssize_t r;
 698    size_t sz;
 699
 700    if (req->cdb[0] == PERSISTENT_RESERVE_IN && resp->result == GOOD) {
 701        assert(resp->sz <= req->sz && resp->sz <= sizeof(client->data));
 702    } else {
 703        assert(resp->sz == 0);
 704    }
 705
 706    sz = resp->sz;
 707
 708    resp->result = cpu_to_be32(resp->result);
 709    resp->sz = cpu_to_be32(resp->sz);
 710    r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 711                              (char *) resp, sizeof(*resp), errp);
 712    if (r < 0) {
 713        return r;
 714    }
 715
 716    r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 717                              (char *) client->data,
 718                              sz, errp);
 719    return r < 0 ? r : 0;
 720}
 721
 722static void coroutine_fn prh_co_entry(void *opaque)
 723{
 724    PRHelperClient *client = opaque;
 725    Error *local_err = NULL;
 726    uint32_t flags;
 727    int r;
 728
 729    qio_channel_set_blocking(QIO_CHANNEL(client->ioc),
 730                             false, NULL);
 731    qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc),
 732                                   qemu_get_aio_context());
 733
 734    /* A very simple negotiation for future extensibility.  No features
 735     * are defined so write 0.
 736     */
 737    flags = cpu_to_be32(0);
 738    r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 739                             (char *) &flags, sizeof(flags), NULL);
 740    if (r < 0) {
 741        goto out;
 742    }
 743
 744    r = qio_channel_read_all(QIO_CHANNEL(client->ioc),
 745                             (char *) &flags, sizeof(flags), NULL);
 746    if (be32_to_cpu(flags) != 0 || r < 0) {
 747        goto out;
 748    }
 749
 750    while (atomic_read(&state) == RUNNING) {
 751        PRHelperRequest req;
 752        PRHelperResponse resp;
 753        int sz;
 754
 755        sz = prh_read_request(client, &req, &resp, &local_err);
 756        if (sz < 0) {
 757            break;
 758        }
 759
 760        num_active_sockets++;
 761        if (req.cdb[0] == PERSISTENT_RESERVE_OUT) {
 762            r = do_pr_out(req.fd, req.cdb, resp.sense,
 763                          client->data, sz);
 764            resp.sz = 0;
 765        } else {
 766            resp.sz = sizeof(client->data);
 767            r = do_pr_in(req.fd, req.cdb, resp.sense,
 768                         client->data, &resp.sz);
 769            resp.sz = MIN(resp.sz, sz);
 770        }
 771        num_active_sockets--;
 772        close(req.fd);
 773        if (r == -1) {
 774            break;
 775        }
 776        resp.result = r;
 777
 778        if (prh_write_response(client, &req, &resp, &local_err) < 0) {
 779            break;
 780        }
 781    }
 782
 783    if (local_err) {
 784        if (verbose == 0) {
 785            error_free(local_err);
 786        } else {
 787            error_report_err(local_err);
 788        }
 789    }
 790
 791out:
 792    qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
 793    object_unref(OBJECT(client->ioc));
 794    g_free(client);
 795}
 796
 797static gboolean accept_client(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 798{
 799    QIOChannelSocket *cioc;
 800    PRHelperClient *prh;
 801
 802    cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 803                                     NULL);
 804    if (!cioc) {
 805        return TRUE;
 806    }
 807
 808    prh = g_new(PRHelperClient, 1);
 809    prh->ioc = cioc;
 810    prh->fd = -1;
 811    prh->co = qemu_coroutine_create(prh_co_entry, prh);
 812    qemu_coroutine_enter(prh->co);
 813
 814    return TRUE;
 815}
 816
 817static void termsig_handler(int signum)
 818{
 819    atomic_cmpxchg(&state, RUNNING, TERMINATE);
 820    qemu_notify_event();
 821}
 822
 823static void close_server_socket(void)
 824{
 825    assert(server_ioc);
 826
 827    g_source_remove(server_watch);
 828    server_watch = -1;
 829    object_unref(OBJECT(server_ioc));
 830    num_active_sockets--;
 831}
 832
 833#ifdef CONFIG_LIBCAP
 834static int drop_privileges(void)
 835{
 836    /* clear all capabilities */
 837    capng_clear(CAPNG_SELECT_BOTH);
 838
 839    if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 840                     CAP_SYS_RAWIO) < 0) {
 841        return -1;
 842    }
 843
 844#ifdef CONFIG_MPATH
 845    /* For /dev/mapper/control ioctls */
 846    if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 847                     CAP_SYS_ADMIN) < 0) {
 848        return -1;
 849    }
 850#endif
 851
 852    /* Change user/group id, retaining the capabilities.  Because file descriptors
 853     * are passed via SCM_RIGHTS, we don't need supplementary groups (and in
 854     * fact the helper can run as "nobody").
 855     */
 856    if (capng_change_id(uid != -1 ? uid : getuid(),
 857                        gid != -1 ? gid : getgid(),
 858                        CAPNG_DROP_SUPP_GRP | CAPNG_CLEAR_BOUNDING)) {
 859        return -1;
 860    }
 861
 862    return 0;
 863}
 864#endif
 865
 866int main(int argc, char **argv)
 867{
 868    const char *sopt = "hVk:f:dT:u:g:vq";
 869    struct option lopt[] = {
 870        { "help", no_argument, NULL, 'h' },
 871        { "version", no_argument, NULL, 'V' },
 872        { "socket", required_argument, NULL, 'k' },
 873        { "pidfile", required_argument, NULL, 'f' },
 874        { "daemon", no_argument, NULL, 'd' },
 875        { "trace", required_argument, NULL, 'T' },
 876        { "user", required_argument, NULL, 'u' },
 877        { "group", required_argument, NULL, 'g' },
 878        { "verbose", no_argument, NULL, 'v' },
 879        { "quiet", no_argument, NULL, 'q' },
 880        { NULL, 0, NULL, 0 }
 881    };
 882    int opt_ind = 0;
 883    int loglevel = 1;
 884    int quiet = 0;
 885    int ch;
 886    Error *local_err = NULL;
 887    char *trace_file = NULL;
 888    bool daemonize = false;
 889    bool pidfile_specified = false;
 890    bool socket_path_specified = false;
 891    unsigned socket_activation;
 892
 893    struct sigaction sa_sigterm;
 894    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 895    sa_sigterm.sa_handler = termsig_handler;
 896    sigaction(SIGTERM, &sa_sigterm, NULL);
 897    sigaction(SIGINT, &sa_sigterm, NULL);
 898    sigaction(SIGHUP, &sa_sigterm, NULL);
 899
 900    signal(SIGPIPE, SIG_IGN);
 901
 902    error_init(argv[0]);
 903    module_call_init(MODULE_INIT_TRACE);
 904    module_call_init(MODULE_INIT_QOM);
 905    qemu_add_opts(&qemu_trace_opts);
 906    qemu_init_exec_dir(argv[0]);
 907
 908    compute_default_paths();
 909
 910    while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 911        switch (ch) {
 912        case 'k':
 913            g_free(socket_path);
 914            socket_path = g_strdup(optarg);
 915            socket_path_specified = true;
 916            if (socket_path[0] != '/') {
 917                error_report("socket path must be absolute");
 918                exit(EXIT_FAILURE);
 919            }
 920            break;
 921        case 'f':
 922            g_free(pidfile);
 923            pidfile = g_strdup(optarg);
 924            pidfile_specified = true;
 925            break;
 926#ifdef CONFIG_LIBCAP
 927        case 'u': {
 928            unsigned long res;
 929            struct passwd *userinfo = getpwnam(optarg);
 930            if (userinfo) {
 931                uid = userinfo->pw_uid;
 932            } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
 933                       (uid_t)res == res) {
 934                uid = res;
 935            } else {
 936                error_report("invalid user '%s'", optarg);
 937                exit(EXIT_FAILURE);
 938            }
 939            break;
 940        }
 941        case 'g': {
 942            unsigned long res;
 943            struct group *groupinfo = getgrnam(optarg);
 944            if (groupinfo) {
 945                gid = groupinfo->gr_gid;
 946            } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
 947                       (gid_t)res == res) {
 948                gid = res;
 949            } else {
 950                error_report("invalid group '%s'", optarg);
 951                exit(EXIT_FAILURE);
 952            }
 953            break;
 954        }
 955#else
 956        case 'u':
 957        case 'g':
 958            error_report("-%c not supported by this %s", ch, argv[0]);
 959            exit(1);
 960#endif
 961        case 'd':
 962            daemonize = true;
 963            break;
 964        case 'q':
 965            quiet = 1;
 966            break;
 967        case 'v':
 968            ++loglevel;
 969            break;
 970        case 'T':
 971            g_free(trace_file);
 972            trace_file = trace_opt_parse(optarg);
 973            break;
 974        case 'V':
 975            version(argv[0]);
 976            exit(EXIT_SUCCESS);
 977            break;
 978        case 'h':
 979            usage(argv[0]);
 980            exit(EXIT_SUCCESS);
 981            break;
 982        case '?':
 983            error_report("Try `%s --help' for more information.", argv[0]);
 984            exit(EXIT_FAILURE);
 985        }
 986    }
 987
 988    /* set verbosity */
 989    noisy = !quiet && (loglevel >= 3);
 990    verbose = quiet ? 0 : MIN(loglevel, 3);
 991
 992    if (!trace_init_backends()) {
 993        exit(EXIT_FAILURE);
 994    }
 995    trace_init_file(trace_file);
 996    qemu_set_log(LOG_TRACE);
 997
 998#ifdef CONFIG_MPATH
 999    dm_init();
1000    multipath_pr_init();
1001#endif
1002
1003    socket_activation = check_socket_activation();
1004    if (socket_activation == 0) {
1005        SocketAddress saddr;
1006        saddr = (SocketAddress){
1007            .type = SOCKET_ADDRESS_TYPE_UNIX,
1008            .u.q_unix.path = socket_path,
1009        };
1010        server_ioc = qio_channel_socket_new();
1011        if (qio_channel_socket_listen_sync(server_ioc, &saddr,
1012                                           1, &local_err) < 0) {
1013            object_unref(OBJECT(server_ioc));
1014            error_report_err(local_err);
1015            return 1;
1016        }
1017    } else {
1018        /* Using socket activation - check user didn't use -p etc. */
1019        if (socket_path_specified) {
1020            error_report("Unix socket can't be set when using socket activation");
1021            exit(EXIT_FAILURE);
1022        }
1023
1024        /* Can only listen on a single socket.  */
1025        if (socket_activation > 1) {
1026            error_report("%s does not support socket activation with LISTEN_FDS > 1",
1027                         argv[0]);
1028            exit(EXIT_FAILURE);
1029        }
1030        server_ioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD,
1031                                               &local_err);
1032        if (server_ioc == NULL) {
1033            error_report("Failed to use socket activation: %s",
1034                         error_get_pretty(local_err));
1035            exit(EXIT_FAILURE);
1036        }
1037    }
1038
1039    if (qemu_init_main_loop(&local_err)) {
1040        error_report_err(local_err);
1041        exit(EXIT_FAILURE);
1042    }
1043
1044    server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
1045                                         G_IO_IN,
1046                                         accept_client,
1047                                         NULL, NULL);
1048
1049    if (daemonize) {
1050        if (daemon(0, 0) < 0) {
1051            error_report("Failed to daemonize: %s", strerror(errno));
1052            exit(EXIT_FAILURE);
1053        }
1054    }
1055
1056    if ((daemonize || pidfile_specified) &&
1057        !qemu_write_pidfile(pidfile, &local_err)) {
1058        error_report_err(local_err);
1059        exit(EXIT_FAILURE);
1060    }
1061
1062#ifdef CONFIG_LIBCAP
1063    if (drop_privileges() < 0) {
1064        error_report("Failed to drop privileges: %s", strerror(errno));
1065        exit(EXIT_FAILURE);
1066    }
1067#endif
1068
1069    state = RUNNING;
1070    do {
1071        main_loop_wait(false);
1072        if (state == TERMINATE) {
1073            state = TERMINATING;
1074            close_server_socket();
1075        }
1076    } while (num_active_sockets > 0);
1077
1078    exit(EXIT_SUCCESS);
1079}
1080