scsi/qemu-pr-helper.c

   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 "qapi/error.h"
  40 #include "qemu-common.h"
  41 #include "qemu/cutils.h"
  42 #include "qemu/main-loop.h"
  43 #include "qemu/error-report.h"
  44 #include "qemu/config-file.h"
  45 #include "qemu/bswap.h"
  46 #include "qemu/log.h"
  47 #include "qemu/systemd.h"
  48 #include "qapi/util.h"
  49 #include "qapi/qmp/qstring.h"
  50 #include "io/channel-socket.h"
  51 #include "trace/control.h"
  52 #include "qemu-version.h"
  53
  54 #include "block/aio.h"
  55 #include "block/thread-pool.h"
  56
  57 #include "scsi/constants.h"
  58 #include "scsi/utils.h"
  59 #include "pr-helper.h"
  60
  61 #define PR_OUT_FIXED_PARAM_SIZE 24
  62
  63 static char *socket_path;
  64 static char *pidfile;
  65 static enum { RUNNING, TERMINATE, TERMINATING } state;
  66 static QIOChannelSocket *server_ioc;
  67 static int server_watch;
  68 static int num_active_sockets = 1;
  69 static int noisy;
  70 static int verbose;
  71
  72 #ifdef CONFIG_LIBCAP
  73 static int uid = -1;
  74 static int gid = -1;
  75 #endif
  76
  77 static void usage(const char *name)
  78 {
  79     (printf) (
  80 "Usage: %s [OPTIONS] FILE\n"
  81 "Persistent Reservation helper program for QEMU\n"
  82 "\n"
  83 "  -h, --help                display this help and exit\n"
  84 "  -V, --version             output version information and exit\n"
  85 "\n"
  86 "  -d, --daemon              run in the background\n"
  87 "  -f, --pidfile=PATH        PID file when running as a daemon\n"
  88 "                            (default '%s')\n"
  89 "  -k, --socket=PATH         path to the unix socket\n"
  90 "                            (default '%s')\n"
  91 "  -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
  92 "                            specify tracing options\n"
  93 #ifdef CONFIG_LIBCAP
  94 "  -u, --user=USER           user to drop privileges to\n"
  95 "  -g, --group=GROUP         group to drop privileges to\n"
  96 #endif
  97 "\n"
  98 QEMU_HELP_BOTTOM "\n"
  99     , name, pidfile, socket_path);
 100 }
 101
 102 static void version(const char *name)
 103 {
 104     printf(
 105 "%s " QEMU_VERSION QEMU_PKGVERSION "\n"
 106 "Written by Paolo Bonzini.\n"
 107 "\n"
 108 QEMU_COPYRIGHT "\n"
 109 "This is free software; see the source for copying conditions.  There is NO\n"
 110 "warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
 111     , name);
 112 }
 113
 114 static void write_pidfile(void)
 115 {
 116     int pidfd;
 117     char pidstr[32];
 118
 119     pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 120     if (pidfd == -1) {
 121         error_report("Cannot open pid file, %s", strerror(errno));
 122         exit(EXIT_FAILURE);
 123     }
 124
 125     if (lockf(pidfd, F_TLOCK, 0)) {
 126         error_report("Cannot lock pid file, %s", strerror(errno));
 127         goto fail;
 128     }
 129     if (ftruncate(pidfd, 0)) {
 130         error_report("Failed to truncate pid file");
 131         goto fail;
 132     }
 133
 134     snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
 135     if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
 136         error_report("Failed to write pid file");
 137         goto fail;
 138     }
 139     return;
 140
 141 fail:
 142     unlink(pidfile);
 143     close(pidfd);
 144     exit(EXIT_FAILURE);
 145 }
 146
 147 /* SG_IO support */
 148
 149 typedef struct PRHelperSGIOData {
 150     int fd;
 151     const uint8_t *cdb;
 152     uint8_t *sense;
 153     uint8_t *buf;
 154     int sz;              /* input/output */
 155     int dir;
 156 } PRHelperSGIOData;
 157
 158 static int do_sgio_worker(void *opaque)
 159 {
 160     PRHelperSGIOData *data = opaque;
 161     struct sg_io_hdr io_hdr;
 162     int ret;
 163     int status;
 164     SCSISense sense_code;
 165
 166     memset(data->sense, 0, PR_HELPER_SENSE_SIZE);
 167     memset(&io_hdr, 0, sizeof(io_hdr));
 168     io_hdr.interface_id = 'S';
 169     io_hdr.cmd_len = PR_HELPER_CDB_SIZE;
 170     io_hdr.cmdp = (uint8_t *)data->cdb;
 171     io_hdr.sbp = data->sense;
 172     io_hdr.mx_sb_len = PR_HELPER_SENSE_SIZE;
 173     io_hdr.timeout = 1;
 174     io_hdr.dxfer_direction = data->dir;
 175     io_hdr.dxferp = (char *)data->buf;
 176     io_hdr.dxfer_len = data->sz;
 177     ret = ioctl(data->fd, SG_IO, &io_hdr);
 178     status = sg_io_sense_from_errno(ret < 0 ? errno : 0, &io_hdr,
 179                                     &sense_code);
 180     if (status == GOOD) {
 181         data->sz -= io_hdr.resid;
 182     } else {
 183         data->sz = 0;
 184     }
 185
 186     if (status == CHECK_CONDITION &&
 187         !(io_hdr.driver_status & SG_ERR_DRIVER_SENSE)) {
 188         scsi_build_sense(data->sense, sense_code);
 189     }
 190
 191     return status;
 192 }
 193
 194 static int do_sgio(int fd, const uint8_t *cdb, uint8_t *sense,
 195                     uint8_t *buf, int *sz, int dir)
 196 {
 197     ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
 198     int r;
 199
 200     PRHelperSGIOData data = {
 201         .fd = fd,
 202         .cdb = cdb,
 203         .sense = sense,
 204         .buf = buf,
 205         .sz = *sz,
 206         .dir = dir,
 207     };
 208
 209     r = thread_pool_submit_co(pool, do_sgio_worker, &data);
 210     *sz = data.sz;
 211     return r;
 212 }
 213
 214 /* Device mapper interface */
 215
 216 #ifdef CONFIG_MPATH
 217 #define CONTROL_PATH "/dev/mapper/control"
 218
 219 typedef struct DMData {
 220     struct dm_ioctl dm;
 221     uint8_t data[1024];
 222 } DMData;
 223
 224 static int control_fd;
 225
 226 static void *dm_ioctl(int ioc, struct dm_ioctl *dm)
 227 {
 228     static DMData d;
 229     memcpy(&d.dm, dm, sizeof(d.dm));
 230     QEMU_BUILD_BUG_ON(sizeof(d.data) < sizeof(struct dm_target_spec));
 231
 232     d.dm.version[0] = DM_VERSION_MAJOR;
 233     d.dm.version[1] = 0;
 234     d.dm.version[2] = 0;
 235     d.dm.data_size = 1024;
 236     d.dm.data_start = offsetof(DMData, data);
 237     if (ioctl(control_fd, ioc, &d) < 0) {
 238         return NULL;
 239     }
 240     memcpy(dm, &d.dm, sizeof(d.dm));
 241     return &d.data;
 242 }
 243
 244 static void *dm_dev_ioctl(int fd, int ioc, struct dm_ioctl *dm)
 245 {
 246     struct stat st;
 247     int r;
 248
 249     r = fstat(fd, &st);
 250     if (r < 0) {
 251         perror("fstat");
 252         exit(1);
 253     }
 254
 255     dm->dev = st.st_rdev;
 256     return dm_ioctl(ioc, dm);
 257 }
 258
 259 static void dm_init(void)
 260 {
 261     control_fd = open(CONTROL_PATH, O_RDWR);
 262     if (control_fd < 0) {
 263         perror("Cannot open " CONTROL_PATH);
 264         exit(1);
 265     }
 266     struct dm_ioctl dm = { 0 };
 267     if (!dm_ioctl(DM_VERSION, &dm)) {
 268         perror("ioctl");
 269         exit(1);
 270     }
 271     if (dm.version[0] != DM_VERSION_MAJOR) {
 272         fprintf(stderr, "Unsupported device mapper interface");
 273         exit(1);
 274     }
 275 }
 276
 277 /* Variables required by libmultipath and libmpathpersist.  */
 278 QEMU_BUILD_BUG_ON(PR_HELPER_DATA_SIZE > MPATH_MAX_PARAM_LEN);
 279 unsigned mpath_mx_alloc_len = PR_HELPER_DATA_SIZE;
 280 int logsink;
 281
 282 static void multipath_pr_init(void)
 283 {
 284     static struct udev *udev;
 285
 286     udev = udev_new();
 287     mpath_lib_init(udev);
 288 }
 289
 290 static int is_mpath(int fd)
 291 {
 292     struct dm_ioctl dm = { .flags = DM_NOFLUSH_FLAG };
 293     struct dm_target_spec *tgt;
 294
 295     tgt = dm_dev_ioctl(fd, DM_TABLE_STATUS, &dm);
 296     if (!tgt) {
 297         if (errno == ENXIO) {
 298             return 0;
 299         }
 300         perror("ioctl");
 301         exit(EXIT_FAILURE);
 302     }
 303     return !strncmp(tgt->target_type, "multipath", DM_MAX_TYPE_NAME);
 304 }
 305
 306 static int mpath_reconstruct_sense(int fd, int r, uint8_t *sense)
 307 {
 308     switch (r) {
 309     case MPATH_PR_SUCCESS:
 310         return GOOD;
 311     case MPATH_PR_SENSE_NOT_READY:
 312     case MPATH_PR_SENSE_MEDIUM_ERROR:
 313     case MPATH_PR_SENSE_HARDWARE_ERROR:
 314     case MPATH_PR_SENSE_ABORTED_COMMAND:
 315         {
 316             /* libmpathpersist ate the exact sense.  Try to find it by
 317              * issuing TEST UNIT READY.
 318              */
 319             uint8_t cdb[6] = { TEST_UNIT_READY };
 320             int sz = 0;
 321             return do_sgio(fd, cdb, sense, NULL, &sz, SG_DXFER_NONE);
 322         }
 323
 324     case MPATH_PR_SENSE_UNIT_ATTENTION:
 325         /* Congratulations libmpathpersist, you ruined the Unit Attention...
 326          * Return a heavyweight one.
 327          */
 328         scsi_build_sense(sense, SENSE_CODE(SCSI_BUS_RESET));
 329         return CHECK_CONDITION;
 330     case MPATH_PR_SENSE_INVALID_OP:
 331         /* Only one valid sense.  */
 332         scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 333         return CHECK_CONDITION;
 334     case MPATH_PR_ILLEGAL_REQ:
 335         /* Guess.  */
 336         scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 337         return CHECK_CONDITION;
 338     case MPATH_PR_NO_SENSE:
 339         scsi_build_sense(sense, SENSE_CODE(NO_SENSE));
 340         return CHECK_CONDITION;
 341
 342     case MPATH_PR_RESERV_CONFLICT:
 343         return RESERVATION_CONFLICT;
 344
 345     case MPATH_PR_OTHER:
 346     default:
 347         scsi_build_sense(sense, SENSE_CODE(LUN_COMM_FAILURE));
 348         return CHECK_CONDITION;
 349     }
 350 }
 351
 352 static int multipath_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 353                            uint8_t *data, int sz)
 354 {
 355     int rq_servact = cdb[1];
 356     struct prin_resp resp;
 357     size_t written;
 358     int r;
 359
 360     switch (rq_servact) {
 361     case MPATH_PRIN_RKEY_SA:
 362     case MPATH_PRIN_RRES_SA:
 363     case MPATH_PRIN_RCAP_SA:
 364         break;
 365     case MPATH_PRIN_RFSTAT_SA:
 366         /* Nobody implements it anyway, so bail out. */
 367     default:
 368         /* Cannot parse any other output.  */
 369         scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
 370         return CHECK_CONDITION;
 371     }
 372
 373     r = mpath_persistent_reserve_in(fd, rq_servact, &resp, noisy, verbose);
 374     if (r == MPATH_PR_SUCCESS) {
 375         switch (rq_servact) {
 376         case MPATH_PRIN_RKEY_SA:
 377         case MPATH_PRIN_RRES_SA: {
 378             struct prin_readdescr *out = &resp.prin_descriptor.prin_readkeys;
 379             assert(sz >= 8);
 380             written = MIN(out->additional_length + 8, sz);
 381             stl_be_p(&data[0], out->prgeneration);
 382             stl_be_p(&data[4], out->additional_length);
 383             memcpy(&data[8], out->key_list, written - 8);
 384             break;
 385         }
 386         case MPATH_PRIN_RCAP_SA: {
 387             struct prin_capdescr *out = &resp.prin_descriptor.prin_readcap;
 388             assert(sz >= 6);
 389             written = 6;
 390             stw_be_p(&data[0], out->length);
 391             data[2] = out->flags[0];
 392             data[3] = out->flags[1];
 393             stw_be_p(&data[4], out->pr_type_mask);
 394             break;
 395         }
 396         default:
 397             scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 398             return CHECK_CONDITION;
 399         }
 400         assert(written <= sz);
 401         memset(data + written, 0, sz - written);
 402     }
 403
 404     return mpath_reconstruct_sense(fd, r, sense);
 405 }
 406
 407 static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
 408                             const uint8_t *param, int sz)
 409 {
 410     int rq_servact = cdb[1];
 411     int rq_scope = cdb[2] >> 4;
 412     int rq_type = cdb[2] & 0xf;
 413     struct prout_param_descriptor paramp;
 414     char transportids[PR_HELPER_DATA_SIZE];
 415     int r;
 416
 417     switch (rq_servact) {
 418     case MPATH_PROUT_REG_SA:
 419     case MPATH_PROUT_RES_SA:
 420     case MPATH_PROUT_REL_SA:
 421     case MPATH_PROUT_CLEAR_SA:
 422     case MPATH_PROUT_PREE_SA:
 423     case MPATH_PROUT_PREE_AB_SA:
 424     case MPATH_PROUT_REG_IGN_SA:
 425         break;
 426     case MPATH_PROUT_REG_MOV_SA:
 427         /* Not supported by struct prout_param_descriptor.  */
 428     default:
 429         /* Cannot parse any other input.  */
 430         scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
 431         return CHECK_CONDITION;
 432     }
 433
 434     /* Convert input data, especially transport IDs, to the structs
 435      * used by libmpathpersist (which, of course, will immediately
 436      * do the opposite).
 437      */
 438     memset(&paramp, 0, sizeof(paramp));
 439     memcpy(&paramp.key, &param[0], 8);
 440     memcpy(&paramp.sa_key, &param[8], 8);
 441     paramp.sa_flags = param[10];
 442     if (sz > PR_OUT_FIXED_PARAM_SIZE) {
 443         size_t transportid_len;
 444         int i, j;
 445         if (sz < PR_OUT_FIXED_PARAM_SIZE + 4) {
 446             scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
 447             return CHECK_CONDITION;
 448         }
 449         transportid_len = ldl_be_p(&param[24]) + PR_OUT_FIXED_PARAM_SIZE + 4;
 450         if (transportid_len > sz) {
 451             scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 452             return CHECK_CONDITION;
 453         }
 454         for (i = PR_OUT_FIXED_PARAM_SIZE + 4, j = 0; i < transportid_len; ) {
 455             struct transportid *id = (struct transportid *) &transportids[j];
 456             int len;
 457
 458             id->format_code = param[i] & 0xc0;
 459             id->protocol_id = param[i] & 0x0f;
 460             switch (param[i] & 0xcf) {
 461             case 0:
 462                 /* FC transport.  */
 463                 if (i + 24 > transportid_len) {
 464                     goto illegal_req;
 465                 }
 466                 memcpy(id->n_port_name, &param[i + 8], 8);
 467                 j += offsetof(struct transportid, n_port_name[8]);
 468                 i += 24;
 469                 break;
 470             case 3:
 471             case 0x43:
 472                 /* iSCSI transport.  */
 473                 len = lduw_be_p(&param[i + 2]);
 474                 if (len > 252 || (len & 3) || i + len + 4 > transportid_len) {
 475                     /* For format code 00, the standard says the maximum is 223
 476                      * plus the NUL terminator.  For format code 01 there is no
 477                      * maximum length, but libmpathpersist ignores the first
 478                      * byte of id->iscsi_name so our maximum is 252.
 479                      */
 480                     goto illegal_req;
 481                 }
 482                 if (memchr(&param[i + 4], 0, len) == NULL) {
 483                     goto illegal_req;
 484                 }
 485                 memcpy(id->iscsi_name, &param[i + 2], len + 2);
 486                 j += offsetof(struct transportid, iscsi_name[len + 2]);
 487                 i += len + 4;
 488                 break;
 489             case 6:
 490                 /* SAS transport.  */
 491                 if (i + 24 > transportid_len) {
 492                     goto illegal_req;
 493                 }
 494                 memcpy(id->sas_address, &param[i + 4], 8);
 495                 j += offsetof(struct transportid, sas_address[8]);
 496                 i += 24;
 497                 break;
 498             default:
 499             illegal_req:
 500                 scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 501                 return CHECK_CONDITION;
 502             }
 503
 504             paramp.trnptid_list[paramp.num_transportid++] = id;
 505         }
 506     }
 507
 508     r = mpath_persistent_reserve_out(fd, rq_servact, rq_scope, rq_type,
 509                                      &paramp, noisy, verbose);
 510     return mpath_reconstruct_sense(fd, r, sense);
 511 }
 512 #endif
 513
 514 static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 515                     uint8_t *data, int *resp_sz)
 516 {
 517 #ifdef CONFIG_MPATH
 518     if (is_mpath(fd)) {
 519         /* multipath_pr_in fills the whole input buffer.  */
 520         return multipath_pr_in(fd, cdb, sense, data, *resp_sz);
 521     }
 522 #endif
 523
 524     return do_sgio(fd, cdb, sense, data, resp_sz,
 525                    SG_DXFER_FROM_DEV);
 526 }
 527
 528 static int do_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
 529                      const uint8_t *param, int sz)
 530 {
 531     int resp_sz;
 532 #ifdef CONFIG_MPATH
 533     if (is_mpath(fd)) {
 534         return multipath_pr_out(fd, cdb, sense, param, sz);
 535     }
 536 #endif
 537
 538     resp_sz = sz;
 539     return do_sgio(fd, cdb, sense, (uint8_t *)param, &resp_sz,
 540                    SG_DXFER_TO_DEV);
 541 }
 542
 543 /* Client */
 544
 545 typedef struct PRHelperClient {
 546     QIOChannelSocket *ioc;
 547     Coroutine *co;
 548     int fd;
 549     uint8_t data[PR_HELPER_DATA_SIZE];
 550 } PRHelperClient;
 551
 552 typedef struct PRHelperRequest {
 553     int fd;
 554     size_t sz;
 555     uint8_t cdb[PR_HELPER_CDB_SIZE];
 556 } PRHelperRequest;
 557
 558 static int coroutine_fn prh_read(PRHelperClient *client, void *buf, int sz,
 559                                  Error **errp)
 560 {
 561     int ret = 0;
 562
 563     while (sz > 0) {
 564         int *fds = NULL;
 565         size_t nfds = 0;
 566         int i;
 567         struct iovec iov;
 568         ssize_t n_read;
 569
 570         iov.iov_base = buf;
 571         iov.iov_len = sz;
 572         n_read = qio_channel_readv_full(QIO_CHANNEL(client->ioc), &iov, 1,
 573                                         &fds, &nfds, errp);
 574
 575         if (n_read == QIO_CHANNEL_ERR_BLOCK) {
 576             qio_channel_yield(QIO_CHANNEL(client->ioc), G_IO_IN);
 577             continue;
 578         }
 579         if (n_read <= 0) {
 580             ret = n_read ? n_read : -1;
 581             goto err;
 582         }
 583
 584         /* Stash one file descriptor per request.  */
 585         if (nfds) {
 586             bool too_many = false;
 587             for (i = 0; i < nfds; i++) {
 588                 if (client->fd == -1) {
 589                     client->fd = fds[i];
 590                 } else {
 591                     close(fds[i]);
 592                     too_many = true;
 593                 }
 594             }
 595             g_free(fds);
 596             if (too_many) {
 597                 ret = -1;
 598                 goto err;
 599             }
 600         }
 601
 602         buf += n_read;
 603         sz -= n_read;
 604     }
 605
 606     return 0;
 607
 608 err:
 609     if (client->fd != -1) {
 610         close(client->fd);
 611         client->fd = -1;
 612     }
 613     return ret;
 614 }
 615
 616 static int coroutine_fn prh_read_request(PRHelperClient *client,
 617                                          PRHelperRequest *req,
 618                                          PRHelperResponse *resp, Error **errp)
 619 {
 620     uint32_t sz;
 621
 622     if (prh_read(client, req->cdb, sizeof(req->cdb), NULL) < 0) {
 623         return -1;
 624     }
 625
 626     if (client->fd == -1) {
 627         error_setg(errp, "No file descriptor in request.");
 628         return -1;
 629     }
 630
 631     if (req->cdb[0] != PERSISTENT_RESERVE_OUT &&
 632         req->cdb[0] != PERSISTENT_RESERVE_IN) {
 633         error_setg(errp, "Invalid CDB, closing socket.");
 634         goto out_close;
 635     }
 636
 637     sz = scsi_cdb_xfer(req->cdb);
 638     if (sz > sizeof(client->data)) {
 639         goto out_close;
 640     }
 641
 642     if (req->cdb[0] == PERSISTENT_RESERVE_OUT) {
 643         if (qio_channel_read_all(QIO_CHANNEL(client->ioc),
 644                                  (char *)client->data, sz,
 645                                  errp) < 0) {
 646             goto out_close;
 647         }
 648         if ((fcntl(client->fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
 649             scsi_build_sense(resp->sense, SENSE_CODE(INVALID_OPCODE));
 650             sz = 0;
 651         } else if (sz < PR_OUT_FIXED_PARAM_SIZE) {
 652             /* Illegal request, Parameter list length error.  This isn't fatal;
 653              * we have read the data, send an error without closing the socket.
 654              */
 655             scsi_build_sense(resp->sense, SENSE_CODE(INVALID_PARAM_LEN));
 656             sz = 0;
 657         }
 658         if (sz == 0) {
 659             resp->result = CHECK_CONDITION;
 660             close(client->fd);
 661             client->fd = -1;
 662         }
 663     }
 664
 665     req->fd = client->fd;
 666     req->sz = sz;
 667     client->fd = -1;
 668     return sz;
 669
 670 out_close:
 671     close(client->fd);
 672     client->fd = -1;
 673     return -1;
 674 }
 675
 676 static int coroutine_fn prh_write_response(PRHelperClient *client,
 677                                            PRHelperRequest *req,
 678                                            PRHelperResponse *resp, Error **errp)
 679 {
 680     ssize_t r;
 681     size_t sz;
 682
 683     if (req->cdb[0] == PERSISTENT_RESERVE_IN && resp->result == GOOD) {
 684         assert(resp->sz <= req->sz && resp->sz <= sizeof(client->data));
 685     } else {
 686         assert(resp->sz == 0);
 687     }
 688
 689     sz = resp->sz;
 690
 691     resp->result = cpu_to_be32(resp->result);
 692     resp->sz = cpu_to_be32(resp->sz);
 693     r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 694                               (char *) resp, sizeof(*resp), errp);
 695     if (r < 0) {
 696         return r;
 697     }
 698
 699     r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 700                               (char *) client->data,
 701                               sz, errp);
 702     return r < 0 ? r : 0;
 703 }
 704
 705 static void coroutine_fn prh_co_entry(void *opaque)
 706 {
 707     PRHelperClient *client = opaque;
 708     Error *local_err = NULL;
 709     uint32_t flags;
 710     int r;
 711
 712     qio_channel_set_blocking(QIO_CHANNEL(client->ioc),
 713                              false, NULL);
 714     qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc),
 715                                    qemu_get_aio_context());
 716
 717     /* A very simple negotiation for future extensibility.  No features
 718      * are defined so write 0.
 719      */
 720     flags = cpu_to_be32(0);
 721     r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 722                              (char *) &flags, sizeof(flags), NULL);
 723     if (r < 0) {
 724         goto out;
 725     }
 726
 727     r = qio_channel_read_all(QIO_CHANNEL(client->ioc),
 728                              (char *) &flags, sizeof(flags), NULL);
 729     if (be32_to_cpu(flags) != 0 || r < 0) {
 730         goto out;
 731     }
 732
 733     while (atomic_read(&state) == RUNNING) {
 734         PRHelperRequest req;
 735         PRHelperResponse resp;
 736         int sz;
 737
 738         sz = prh_read_request(client, &req, &resp, &local_err);
 739         if (sz < 0) {
 740             break;
 741         }
 742
 743         if (sz > 0) {
 744             num_active_sockets++;
 745             if (req.cdb[0] == PERSISTENT_RESERVE_OUT) {
 746                 r = do_pr_out(req.fd, req.cdb, resp.sense,
 747                               client->data, sz);
 748                 resp.sz = 0;
 749             } else {
 750                 resp.sz = sizeof(client->data);
 751                 r = do_pr_in(req.fd, req.cdb, resp.sense,
 752                              client->data, &resp.sz);
 753                 resp.sz = MIN(resp.sz, sz);
 754             }
 755             num_active_sockets--;
 756             close(req.fd);
 757             if (r == -1) {
 758                 break;
 759             }
 760             resp.result = r;
 761         }
 762
 763         if (prh_write_response(client, &req, &resp, &local_err) < 0) {
 764             break;
 765         }
 766     }
 767
 768     if (local_err) {
 769         if (verbose == 0) {
 770             error_free(local_err);
 771         } else {
 772             error_report_err(local_err);
 773         }
 774     }
 775
 776 out:
 777     qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
 778     object_unref(OBJECT(client->ioc));
 779     g_free(client);
 780 }
 781
 782 static gboolean accept_client(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 783 {
 784     QIOChannelSocket *cioc;
 785     PRHelperClient *prh;
 786
 787     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 788                                      NULL);
 789     if (!cioc) {
 790         return TRUE;
 791     }
 792
 793     prh = g_new(PRHelperClient, 1);
 794     prh->ioc = cioc;
 795     prh->fd = -1;
 796     prh->co = qemu_coroutine_create(prh_co_entry, prh);
 797     qemu_coroutine_enter(prh->co);
 798
 799     return TRUE;
 800 }
 801
 802
 803 /*
 804  * Check socket parameters compatibility when socket activation is used.
 805  */
 806 static const char *socket_activation_validate_opts(void)
 807 {
 808     if (socket_path != NULL) {
 809         return "Unix socket can't be set when using socket activation";
 810     }
 811
 812     return NULL;
 813 }
 814
 815 static void compute_default_paths(void)
 816 {
 817     if (!socket_path) {
 818         socket_path = qemu_get_local_state_pathname("run/qemu-pr-helper.sock");
 819     }
 820 }
 821
 822 static void termsig_handler(int signum)
 823 {
 824     atomic_cmpxchg(&state, RUNNING, TERMINATE);
 825     qemu_notify_event();
 826 }
 827
 828 static void close_server_socket(void)
 829 {
 830     assert(server_ioc);
 831
 832     g_source_remove(server_watch);
 833     server_watch = -1;
 834     object_unref(OBJECT(server_ioc));
 835     num_active_sockets--;
 836 }
 837
 838 #ifdef CONFIG_LIBCAP
 839 static int drop_privileges(void)
 840 {
 841     /* clear all capabilities */
 842     capng_clear(CAPNG_SELECT_BOTH);
 843
 844     if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 845                      CAP_SYS_RAWIO) < 0) {
 846         return -1;
 847     }
 848
 849 #ifdef CONFIG_MPATH
 850     /* For /dev/mapper/control ioctls */
 851     if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 852                      CAP_SYS_ADMIN) < 0) {
 853         return -1;
 854     }
 855 #endif
 856
 857     /* Change user/group id, retaining the capabilities.  Because file descriptors
 858      * are passed via SCM_RIGHTS, we don't need supplementary groups (and in
 859      * fact the helper can run as "nobody").
 860      */
 861     if (capng_change_id(uid != -1 ? uid : getuid(),
 862                         gid != -1 ? gid : getgid(),
 863                         CAPNG_DROP_SUPP_GRP | CAPNG_CLEAR_BOUNDING)) {
 864         return -1;
 865     }
 866
 867     return 0;
 868 }
 869 #endif
 870
 871 int main(int argc, char **argv)
 872 {
 873     const char *sopt = "hVk:fdT:u:g:vq";
 874     struct option lopt[] = {
 875         { "help", no_argument, NULL, 'h' },
 876         { "version", no_argument, NULL, 'V' },
 877         { "socket", required_argument, NULL, 'k' },
 878         { "pidfile", no_argument, NULL, 'f' },
 879         { "daemon", no_argument, NULL, 'd' },
 880         { "trace", required_argument, NULL, 'T' },
 881         { "user", required_argument, NULL, 'u' },
 882         { "group", required_argument, NULL, 'g' },
 883         { "verbose", no_argument, NULL, 'v' },
 884         { "quiet", no_argument, NULL, 'q' },
 885         { NULL, 0, NULL, 0 }
 886     };
 887     int opt_ind = 0;
 888     int loglevel = 1;
 889     int quiet = 0;
 890     int ch;
 891     Error *local_err = NULL;
 892     char *trace_file = NULL;
 893     bool daemonize = false;
 894     unsigned socket_activation;
 895
 896     struct sigaction sa_sigterm;
 897     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 898     sa_sigterm.sa_handler = termsig_handler;
 899     sigaction(SIGTERM, &sa_sigterm, NULL);
 900     sigaction(SIGINT, &sa_sigterm, NULL);
 901     sigaction(SIGHUP, &sa_sigterm, NULL);
 902
 903     signal(SIGPIPE, SIG_IGN);
 904
 905     module_call_init(MODULE_INIT_TRACE);
 906     module_call_init(MODULE_INIT_QOM);
 907     qemu_add_opts(&qemu_trace_opts);
 908     qemu_init_exec_dir(argv[0]);
 909
 910     pidfile = qemu_get_local_state_pathname("run/qemu-pr-helper.pid");
 911
 912     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 913         switch (ch) {
 914         case 'k':
 915             socket_path = optarg;
 916             if (socket_path[0] != '/') {
 917                 error_report("socket path must be absolute");
 918                 exit(EXIT_FAILURE);
 919             }
 920             break;
 921         case 'f':
 922             pidfile = optarg;
 923             break;
 924 #ifdef CONFIG_LIBCAP
 925         case 'u': {
 926             unsigned long res;
 927             struct passwd *userinfo = getpwnam(optarg);
 928             if (userinfo) {
 929                 uid = userinfo->pw_uid;
 930             } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
 931                        (uid_t)res == res) {
 932                 uid = res;
 933             } else {
 934                 error_report("invalid user '%s'", optarg);
 935                 exit(EXIT_FAILURE);
 936             }
 937             break;
 938         }
 939         case 'g': {
 940             unsigned long res;
 941             struct group *groupinfo = getgrnam(optarg);
 942             if (groupinfo) {
 943                 gid = groupinfo->gr_gid;
 944             } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
 945                        (gid_t)res == res) {
 946                 gid = res;
 947             } else {
 948                 error_report("invalid group '%s'", optarg);
 949                 exit(EXIT_FAILURE);
 950             }
 951             break;
 952         }
 953 #else
 954         case 'u':
 955         case 'g':
 956             error_report("-%c not supported by this %s", ch, argv[0]);
 957             exit(1);
 958 #endif
 959         case 'd':
 960             daemonize = true;
 961             break;
 962         case 'q':
 963             quiet = 1;
 964             break;
 965         case 'v':
 966             ++loglevel;
 967             break;
 968         case 'T':
 969             g_free(trace_file);
 970             trace_file = trace_opt_parse(optarg);
 971             break;
 972         case 'V':
 973             version(argv[0]);
 974             exit(EXIT_SUCCESS);
 975             break;
 976         case 'h':
 977             usage(argv[0]);
 978             exit(EXIT_SUCCESS);
 979             break;
 980         case '?':
 981             error_report("Try `%s --help' for more information.", argv[0]);
 982             exit(EXIT_FAILURE);
 983         }
 984     }
 985
 986     /* set verbosity */
 987     noisy = !quiet && (loglevel >= 3);
 988     verbose = quiet ? 0 : MIN(loglevel, 3);
 989
 990     if (!trace_init_backends()) {
 991         exit(EXIT_FAILURE);
 992     }
 993     trace_init_file(trace_file);
 994     qemu_set_log(LOG_TRACE);
 995
 996 #ifdef CONFIG_MPATH
 997     dm_init();
 998     multipath_pr_init();
 999 #endif
1000
1001     socket_activation = check_socket_activation();
1002     if (socket_activation == 0) {
1003         SocketAddress saddr;
1004         compute_default_paths();
1005         saddr = (SocketAddress){
1006             .type = SOCKET_ADDRESS_TYPE_UNIX,
1007             .u.q_unix.path = g_strdup(socket_path)
1008         };
1009         server_ioc = qio_channel_socket_new();
1010         if (qio_channel_socket_listen_sync(server_ioc, &saddr, &local_err) < 0) {
1011             object_unref(OBJECT(server_ioc));
1012             error_report_err(local_err);
1013             return 1;
1014         }
1015         g_free(saddr.u.q_unix.path);
1016     } else {
1017         /* Using socket activation - check user didn't use -p etc. */
1018         const char *err_msg = socket_activation_validate_opts();
1019         if (err_msg != NULL) {
1020             error_report("%s", err_msg);
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         socket_path = NULL;
1038     }
1039
1040     if (qemu_init_main_loop(&local_err)) {
1041         error_report_err(local_err);
1042         exit(EXIT_FAILURE);
1043     }
1044
1045     server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
1046                                          G_IO_IN,
1047                                          accept_client,
1048                                          NULL, NULL);
1049
1050 #ifdef CONFIG_LIBCAP
1051     if (drop_privileges() < 0) {
1052         error_report("Failed to drop privileges: %s", strerror(errno));
1053         exit(EXIT_FAILURE);
1054     }
1055 #endif
1056
1057     if (daemonize) {
1058         if (daemon(0, 0) < 0) {
1059             error_report("Failed to daemonize: %s", strerror(errno));
1060             exit(EXIT_FAILURE);
1061         }
1062         write_pidfile();
1063     }
1064
1065     state = RUNNING;
1066     do {
1067         main_loop_wait(false);
1068         if (state == TERMINATE) {
1069             state = TERMINATING;
1070             close_server_socket();
1071         }
1072     } while (num_active_sockets > 0);
1073
1074     exit(EXIT_SUCCESS);
1075 }