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_NG
  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
  64 static char *socket_path;
  65 static char *pidfile;
  66 static enum { RUNNING, TERMINATE, TERMINATING } state;
  67 static QIOChannelSocket *server_ioc;
  68 static int server_watch;
  69 static int num_active_sockets = 1;
  70 static int noisy;
  71 static int verbose;
  72
  73 #ifdef CONFIG_LIBCAP_NG
  74 static int uid = -1;
  75 static int gid = -1;
  76 #endif
  77
  78 static 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
  84 static 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_NG
 101 "  -u, --user=USER           user to drop privileges to\n"
 102 "  -g, --group=GROUP         group to drop privileges to\n"
 103 #endif
 104 "\n"
 105 QEMU_HELP_BOTTOM "\n"
 106     , name, pidfile, socket_path);
 107 }
 108
 109 static void version(const char *name)
 110 {
 111     printf(
 112 "%s " QEMU_FULL_VERSION "\n"
 113 "Written by Paolo Bonzini.\n"
 114 "\n"
 115 QEMU_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
 123 typedef 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
 132 static 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
 153     if (ret < 0) {
 154         status = scsi_sense_from_errno(errno, &sense_code);
 155         if (status == CHECK_CONDITION) {
 156             scsi_build_sense(data->sense, sense_code);
 157         }
 158     } else if (io_hdr.host_status != SCSI_HOST_OK) {
 159         status = scsi_sense_from_host_status(io_hdr.host_status, &sense_code);
 160         if (status == CHECK_CONDITION) {
 161             scsi_build_sense(data->sense, sense_code);
 162         }
 163     } else if (io_hdr.driver_status & SG_ERR_DRIVER_TIMEOUT) {
 164         status = BUSY;
 165     } else {
 166         status = io_hdr.status;
 167     }
 168
 169     if (status == GOOD) {
 170         data->sz -= io_hdr.resid;
 171     } else {
 172         data->sz = 0;
 173     }
 174
 175     return status;
 176 }
 177
 178 static int do_sgio(int fd, const uint8_t *cdb, uint8_t *sense,
 179                     uint8_t *buf, int *sz, int dir)
 180 {
 181     ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
 182     int r;
 183
 184     PRHelperSGIOData data = {
 185         .fd = fd,
 186         .cdb = cdb,
 187         .sense = sense,
 188         .buf = buf,
 189         .sz = *sz,
 190         .dir = dir,
 191     };
 192
 193     r = thread_pool_submit_co(pool, do_sgio_worker, &data);
 194     *sz = data.sz;
 195     return r;
 196 }
 197
 198 /* Device mapper interface */
 199
 200 #ifdef CONFIG_MPATH
 201 #define CONTROL_PATH "/dev/mapper/control"
 202
 203 typedef struct DMData {
 204     struct dm_ioctl dm;
 205     uint8_t data[1024];
 206 } DMData;
 207
 208 static int control_fd;
 209
 210 static void *dm_ioctl(int ioc, struct dm_ioctl *dm)
 211 {
 212     static DMData d;
 213     memcpy(&d.dm, dm, sizeof(d.dm));
 214     QEMU_BUILD_BUG_ON(sizeof(d.data) < sizeof(struct dm_target_spec));
 215
 216     d.dm.version[0] = DM_VERSION_MAJOR;
 217     d.dm.version[1] = 0;
 218     d.dm.version[2] = 0;
 219     d.dm.data_size = 1024;
 220     d.dm.data_start = offsetof(DMData, data);
 221     if (ioctl(control_fd, ioc, &d) < 0) {
 222         return NULL;
 223     }
 224     memcpy(dm, &d.dm, sizeof(d.dm));
 225     return &d.data;
 226 }
 227
 228 static void *dm_dev_ioctl(int fd, int ioc, struct dm_ioctl *dm)
 229 {
 230     struct stat st;
 231     int r;
 232
 233     r = fstat(fd, &st);
 234     if (r < 0) {
 235         perror("fstat");
 236         exit(1);
 237     }
 238
 239     dm->dev = st.st_rdev;
 240     return dm_ioctl(ioc, dm);
 241 }
 242
 243 static void dm_init(void)
 244 {
 245     control_fd = open(CONTROL_PATH, O_RDWR);
 246     if (control_fd < 0) {
 247         perror("Cannot open " CONTROL_PATH);
 248         exit(1);
 249     }
 250     struct dm_ioctl dm = { };
 251     if (!dm_ioctl(DM_VERSION, &dm)) {
 252         perror("ioctl");
 253         exit(1);
 254     }
 255     if (dm.version[0] != DM_VERSION_MAJOR) {
 256         fprintf(stderr, "Unsupported device mapper interface");
 257         exit(1);
 258     }
 259 }
 260
 261 /* Variables required by libmultipath and libmpathpersist.  */
 262 QEMU_BUILD_BUG_ON(PR_HELPER_DATA_SIZE > MPATH_MAX_PARAM_LEN);
 263 static struct config *multipath_conf;
 264 unsigned mpath_mx_alloc_len = PR_HELPER_DATA_SIZE;
 265 int logsink;
 266 struct udev *udev;
 267
 268 extern struct config *get_multipath_config(void);
 269 struct config *get_multipath_config(void)
 270 {
 271     return multipath_conf;
 272 }
 273
 274 extern void put_multipath_config(struct config *conf);
 275 void put_multipath_config(struct config *conf)
 276 {
 277 }
 278
 279 static void multipath_pr_init(void)
 280 {
 281     udev = udev_new();
 282 #ifdef CONFIG_MPATH_NEW_API
 283     multipath_conf = mpath_lib_init();
 284 #else
 285     mpath_lib_init(udev);
 286 #endif
 287 }
 288
 289 static int is_mpath(int fd)
 290 {
 291     struct dm_ioctl dm = { .flags = DM_NOFLUSH_FLAG };
 292     struct dm_target_spec *tgt;
 293
 294     tgt = dm_dev_ioctl(fd, DM_TABLE_STATUS, &dm);
 295     if (!tgt) {
 296         if (errno == ENXIO) {
 297             return 0;
 298         }
 299         perror("ioctl");
 300         exit(EXIT_FAILURE);
 301     }
 302     return !strncmp(tgt->target_type, "multipath", DM_MAX_TYPE_NAME);
 303 }
 304
 305 static SCSISense mpath_generic_sense(int r)
 306 {
 307     switch (r) {
 308     case MPATH_PR_SENSE_NOT_READY:
 309          return SENSE_CODE(NOT_READY);
 310     case MPATH_PR_SENSE_MEDIUM_ERROR:
 311          return SENSE_CODE(READ_ERROR);
 312     case MPATH_PR_SENSE_HARDWARE_ERROR:
 313          return SENSE_CODE(TARGET_FAILURE);
 314     case MPATH_PR_SENSE_ABORTED_COMMAND:
 315          return SENSE_CODE(IO_ERROR);
 316     default:
 317          abort();
 318     }
 319 }
 320
 321 static int mpath_reconstruct_sense(int fd, int r, uint8_t *sense)
 322 {
 323     switch (r) {
 324     case MPATH_PR_SUCCESS:
 325         return GOOD;
 326     case MPATH_PR_SENSE_NOT_READY:
 327     case MPATH_PR_SENSE_MEDIUM_ERROR:
 328     case MPATH_PR_SENSE_HARDWARE_ERROR:
 329     case MPATH_PR_SENSE_ABORTED_COMMAND:
 330         {
 331             /* libmpathpersist ate the exact sense.  Try to find it by
 332              * issuing TEST UNIT READY.
 333              */
 334             uint8_t cdb[6] = { TEST_UNIT_READY };
 335             int sz = 0;
 336             int ret = do_sgio(fd, cdb, sense, NULL, &sz, SG_DXFER_NONE);
 337
 338             if (ret != GOOD) {
 339                 return ret;
 340             }
 341             scsi_build_sense(sense, mpath_generic_sense(r));
 342             return CHECK_CONDITION;
 343         }
 344
 345     case MPATH_PR_SENSE_UNIT_ATTENTION:
 346         /* Congratulations libmpathpersist, you ruined the Unit Attention...
 347          * Return a heavyweight one.
 348          */
 349         scsi_build_sense(sense, SENSE_CODE(SCSI_BUS_RESET));
 350         return CHECK_CONDITION;
 351     case MPATH_PR_SENSE_INVALID_OP:
 352         /* Only one valid sense.  */
 353         scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 354         return CHECK_CONDITION;
 355     case MPATH_PR_ILLEGAL_REQ:
 356         /* Guess.  */
 357         scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 358         return CHECK_CONDITION;
 359     case MPATH_PR_NO_SENSE:
 360         scsi_build_sense(sense, SENSE_CODE(NO_SENSE));
 361         return CHECK_CONDITION;
 362
 363     case MPATH_PR_RESERV_CONFLICT:
 364         return RESERVATION_CONFLICT;
 365
 366     case MPATH_PR_OTHER:
 367     default:
 368         scsi_build_sense(sense, SENSE_CODE(LUN_COMM_FAILURE));
 369         return CHECK_CONDITION;
 370     }
 371 }
 372
 373 static int multipath_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 374                            uint8_t *data, int sz)
 375 {
 376     int rq_servact = cdb[1];
 377     struct prin_resp resp;
 378     size_t written;
 379     int r;
 380
 381     switch (rq_servact) {
 382     case MPATH_PRIN_RKEY_SA:
 383     case MPATH_PRIN_RRES_SA:
 384     case MPATH_PRIN_RCAP_SA:
 385         break;
 386     case MPATH_PRIN_RFSTAT_SA:
 387         /* Nobody implements it anyway, so bail out. */
 388     default:
 389         /* Cannot parse any other output.  */
 390         scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
 391         return CHECK_CONDITION;
 392     }
 393
 394     r = mpath_persistent_reserve_in(fd, rq_servact, &resp, noisy, verbose);
 395     if (r == MPATH_PR_SUCCESS) {
 396         switch (rq_servact) {
 397         case MPATH_PRIN_RKEY_SA:
 398         case MPATH_PRIN_RRES_SA: {
 399             struct prin_readdescr *out = &resp.prin_descriptor.prin_readkeys;
 400             assert(sz >= 8);
 401             written = MIN(out->additional_length + 8, sz);
 402             stl_be_p(&data[0], out->prgeneration);
 403             stl_be_p(&data[4], out->additional_length);
 404             memcpy(&data[8], out->key_list, written - 8);
 405             break;
 406         }
 407         case MPATH_PRIN_RCAP_SA: {
 408             struct prin_capdescr *out = &resp.prin_descriptor.prin_readcap;
 409             assert(sz >= 6);
 410             written = 6;
 411             stw_be_p(&data[0], out->length);
 412             data[2] = out->flags[0];
 413             data[3] = out->flags[1];
 414             stw_be_p(&data[4], out->pr_type_mask);
 415             break;
 416         }
 417         default:
 418             scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 419             return CHECK_CONDITION;
 420         }
 421         assert(written <= sz);
 422         memset(data + written, 0, sz - written);
 423     }
 424
 425     return mpath_reconstruct_sense(fd, r, sense);
 426 }
 427
 428 static int multipath_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
 429                             const uint8_t *param, int sz)
 430 {
 431     int rq_servact = cdb[1];
 432     int rq_scope = cdb[2] >> 4;
 433     int rq_type = cdb[2] & 0xf;
 434     g_autofree struct prout_param_descriptor *paramp = NULL;
 435     char transportids[PR_HELPER_DATA_SIZE];
 436     int r;
 437
 438     paramp = g_malloc0(sizeof(struct prout_param_descriptor)
 439                        + sizeof(struct transportid *) * MPATH_MX_TIDS);
 440
 441     if (sz < PR_OUT_FIXED_PARAM_SIZE) {
 442         /* Illegal request, Parameter list length error.  This isn't fatal;
 443          * we have read the data, send an error without closing the socket.
 444          */
 445         scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
 446         return CHECK_CONDITION;
 447     }
 448
 449     switch (rq_servact) {
 450     case MPATH_PROUT_REG_SA:
 451     case MPATH_PROUT_RES_SA:
 452     case MPATH_PROUT_REL_SA:
 453     case MPATH_PROUT_CLEAR_SA:
 454     case MPATH_PROUT_PREE_SA:
 455     case MPATH_PROUT_PREE_AB_SA:
 456     case MPATH_PROUT_REG_IGN_SA:
 457         break;
 458     case MPATH_PROUT_REG_MOV_SA:
 459         /* Not supported by struct prout_param_descriptor.  */
 460     default:
 461         /* Cannot parse any other input.  */
 462         scsi_build_sense(sense, SENSE_CODE(INVALID_FIELD));
 463         return CHECK_CONDITION;
 464     }
 465
 466     /* Convert input data, especially transport IDs, to the structs
 467      * used by libmpathpersist (which, of course, will immediately
 468      * do the opposite).
 469      */
 470     memcpy(&paramp->key, &param[0], 8);
 471     memcpy(&paramp->sa_key, &param[8], 8);
 472     paramp->sa_flags = param[20];
 473     if (sz > PR_OUT_FIXED_PARAM_SIZE) {
 474         size_t transportid_len;
 475         int i, j;
 476         if (sz < PR_OUT_FIXED_PARAM_SIZE + 4) {
 477             scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM_LEN));
 478             return CHECK_CONDITION;
 479         }
 480         transportid_len = ldl_be_p(&param[24]) + PR_OUT_FIXED_PARAM_SIZE + 4;
 481         if (transportid_len > sz) {
 482             scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 483             return CHECK_CONDITION;
 484         }
 485         for (i = PR_OUT_FIXED_PARAM_SIZE + 4, j = 0; i < transportid_len; ) {
 486             struct transportid *id = (struct transportid *) &transportids[j];
 487             int len;
 488
 489             id->format_code = param[i] & 0xc0;
 490             id->protocol_id = param[i] & 0x0f;
 491             switch (param[i] & 0xcf) {
 492             case 0:
 493                 /* FC transport.  */
 494                 if (i + 24 > transportid_len) {
 495                     goto illegal_req;
 496                 }
 497                 memcpy(id->n_port_name, &param[i + 8], 8);
 498                 j += offsetof(struct transportid, n_port_name[8]);
 499                 i += 24;
 500                 break;
 501             case 5:
 502             case 0x45:
 503                 /* iSCSI transport.  */
 504                 len = lduw_be_p(&param[i + 2]);
 505                 if (len > 252 || (len & 3) || i + len + 4 > transportid_len) {
 506                     /* For format code 00, the standard says the maximum is 223
 507                      * plus the NUL terminator.  For format code 01 there is no
 508                      * maximum length, but libmpathpersist ignores the first
 509                      * byte of id->iscsi_name so our maximum is 252.
 510                      */
 511                     goto illegal_req;
 512                 }
 513                 if (memchr(&param[i + 4], 0, len) == NULL) {
 514                     goto illegal_req;
 515                 }
 516                 memcpy(id->iscsi_name, &param[i + 2], len + 2);
 517                 j += offsetof(struct transportid, iscsi_name[len + 2]);
 518                 i += len + 4;
 519                 break;
 520             case 6:
 521                 /* SAS transport.  */
 522                 if (i + 24 > transportid_len) {
 523                     goto illegal_req;
 524                 }
 525                 memcpy(id->sas_address, &param[i + 4], 8);
 526                 j += offsetof(struct transportid, sas_address[8]);
 527                 i += 24;
 528                 break;
 529             default:
 530             illegal_req:
 531                 scsi_build_sense(sense, SENSE_CODE(INVALID_PARAM));
 532                 return CHECK_CONDITION;
 533             }
 534
 535             assert(paramp->num_transportid < MPATH_MX_TIDS);
 536             paramp->trnptid_list[paramp->num_transportid++] = id;
 537         }
 538     }
 539
 540     r = mpath_persistent_reserve_out(fd, rq_servact, rq_scope, rq_type,
 541                                      paramp, noisy, verbose);
 542     return mpath_reconstruct_sense(fd, r, sense);
 543 }
 544 #endif
 545
 546 static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
 547                     uint8_t *data, int *resp_sz)
 548 {
 549 #ifdef CONFIG_MPATH
 550     if (is_mpath(fd)) {
 551         /* multipath_pr_in fills the whole input buffer.  */
 552         int r = multipath_pr_in(fd, cdb, sense, data, *resp_sz);
 553         if (r != GOOD) {
 554             *resp_sz = 0;
 555         }
 556         return r;
 557     }
 558 #endif
 559
 560     return do_sgio(fd, cdb, sense, data, resp_sz,
 561                    SG_DXFER_FROM_DEV);
 562 }
 563
 564 static int do_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
 565                      const uint8_t *param, int sz)
 566 {
 567     int resp_sz;
 568
 569     if ((fcntl(fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
 570         scsi_build_sense(sense, SENSE_CODE(INVALID_OPCODE));
 571         return CHECK_CONDITION;
 572     }
 573
 574 #ifdef CONFIG_MPATH
 575     if (is_mpath(fd)) {
 576         return multipath_pr_out(fd, cdb, sense, param, sz);
 577     }
 578 #endif
 579
 580     resp_sz = sz;
 581     return do_sgio(fd, cdb, sense, (uint8_t *)param, &resp_sz,
 582                    SG_DXFER_TO_DEV);
 583 }
 584
 585 /* Client */
 586
 587 typedef struct PRHelperClient {
 588     QIOChannelSocket *ioc;
 589     Coroutine *co;
 590     int fd;
 591     uint8_t data[PR_HELPER_DATA_SIZE];
 592 } PRHelperClient;
 593
 594 typedef struct PRHelperRequest {
 595     int fd;
 596     size_t sz;
 597     uint8_t cdb[PR_HELPER_CDB_SIZE];
 598 } PRHelperRequest;
 599
 600 static int coroutine_fn prh_read(PRHelperClient *client, void *buf, int sz,
 601                                  Error **errp)
 602 {
 603     int ret = 0;
 604
 605     while (sz > 0) {
 606         int *fds = NULL;
 607         size_t nfds = 0;
 608         int i;
 609         struct iovec iov;
 610         ssize_t n_read;
 611
 612         iov.iov_base = buf;
 613         iov.iov_len = sz;
 614         n_read = qio_channel_readv_full(QIO_CHANNEL(client->ioc), &iov, 1,
 615                                         &fds, &nfds, errp);
 616
 617         if (n_read == QIO_CHANNEL_ERR_BLOCK) {
 618             qio_channel_yield(QIO_CHANNEL(client->ioc), G_IO_IN);
 619             continue;
 620         }
 621         if (n_read <= 0) {
 622             ret = n_read ? n_read : -1;
 623             goto err;
 624         }
 625
 626         /* Stash one file descriptor per request.  */
 627         if (nfds) {
 628             bool too_many = false;
 629             for (i = 0; i < nfds; i++) {
 630                 if (client->fd == -1) {
 631                     client->fd = fds[i];
 632                 } else {
 633                     close(fds[i]);
 634                     too_many = true;
 635                 }
 636             }
 637             g_free(fds);
 638             if (too_many) {
 639                 ret = -1;
 640                 goto err;
 641             }
 642         }
 643
 644         buf += n_read;
 645         sz -= n_read;
 646     }
 647
 648     return 0;
 649
 650 err:
 651     if (client->fd != -1) {
 652         close(client->fd);
 653         client->fd = -1;
 654     }
 655     return ret;
 656 }
 657
 658 static int coroutine_fn prh_read_request(PRHelperClient *client,
 659                                          PRHelperRequest *req,
 660                                          PRHelperResponse *resp, Error **errp)
 661 {
 662     uint32_t sz;
 663
 664     if (prh_read(client, req->cdb, sizeof(req->cdb), NULL) < 0) {
 665         return -1;
 666     }
 667
 668     if (client->fd == -1) {
 669         error_setg(errp, "No file descriptor in request.");
 670         return -1;
 671     }
 672
 673     if (req->cdb[0] != PERSISTENT_RESERVE_OUT &&
 674         req->cdb[0] != PERSISTENT_RESERVE_IN) {
 675         error_setg(errp, "Invalid CDB, closing socket.");
 676         goto out_close;
 677     }
 678
 679     sz = scsi_cdb_xfer(req->cdb);
 680     if (sz > sizeof(client->data)) {
 681         goto out_close;
 682     }
 683
 684     if (req->cdb[0] == PERSISTENT_RESERVE_OUT) {
 685         if (qio_channel_read_all(QIO_CHANNEL(client->ioc),
 686                                  (char *)client->data, sz,
 687                                  errp) < 0) {
 688             goto out_close;
 689         }
 690     }
 691
 692     req->fd = client->fd;
 693     req->sz = sz;
 694     client->fd = -1;
 695     return sz;
 696
 697 out_close:
 698     close(client->fd);
 699     client->fd = -1;
 700     return -1;
 701 }
 702
 703 static int coroutine_fn prh_write_response(PRHelperClient *client,
 704                                            PRHelperRequest *req,
 705                                            PRHelperResponse *resp, Error **errp)
 706 {
 707     ssize_t r;
 708     size_t sz;
 709
 710     if (req->cdb[0] == PERSISTENT_RESERVE_IN && resp->result == GOOD) {
 711         assert(resp->sz <= req->sz && resp->sz <= sizeof(client->data));
 712     } else {
 713         assert(resp->sz == 0);
 714     }
 715
 716     sz = resp->sz;
 717
 718     resp->result = cpu_to_be32(resp->result);
 719     resp->sz = cpu_to_be32(resp->sz);
 720     r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 721                               (char *) resp, sizeof(*resp), errp);
 722     if (r < 0) {
 723         return r;
 724     }
 725
 726     r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 727                               (char *) client->data,
 728                               sz, errp);
 729     return r < 0 ? r : 0;
 730 }
 731
 732 static void coroutine_fn prh_co_entry(void *opaque)
 733 {
 734     PRHelperClient *client = opaque;
 735     Error *local_err = NULL;
 736     uint32_t flags;
 737     int r;
 738
 739     qio_channel_set_blocking(QIO_CHANNEL(client->ioc),
 740                              false, NULL);
 741     qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc),
 742                                    qemu_get_aio_context());
 743
 744     /* A very simple negotiation for future extensibility.  No features
 745      * are defined so write 0.
 746      */
 747     flags = cpu_to_be32(0);
 748     r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
 749                              (char *) &flags, sizeof(flags), NULL);
 750     if (r < 0) {
 751         goto out;
 752     }
 753
 754     r = qio_channel_read_all(QIO_CHANNEL(client->ioc),
 755                              (char *) &flags, sizeof(flags), NULL);
 756     if (be32_to_cpu(flags) != 0 || r < 0) {
 757         goto out;
 758     }
 759
 760     while (qatomic_read(&state) == RUNNING) {
 761         PRHelperRequest req;
 762         PRHelperResponse resp;
 763         int sz;
 764
 765         sz = prh_read_request(client, &req, &resp, &local_err);
 766         if (sz < 0) {
 767             break;
 768         }
 769
 770         num_active_sockets++;
 771         if (req.cdb[0] == PERSISTENT_RESERVE_OUT) {
 772             r = do_pr_out(req.fd, req.cdb, resp.sense,
 773                           client->data, sz);
 774             resp.sz = 0;
 775         } else {
 776             resp.sz = sizeof(client->data);
 777             r = do_pr_in(req.fd, req.cdb, resp.sense,
 778                          client->data, &resp.sz);
 779             resp.sz = MIN(resp.sz, sz);
 780         }
 781         num_active_sockets--;
 782         close(req.fd);
 783         if (r == -1) {
 784             break;
 785         }
 786         resp.result = r;
 787
 788         if (prh_write_response(client, &req, &resp, &local_err) < 0) {
 789             break;
 790         }
 791     }
 792
 793     if (local_err) {
 794         if (verbose == 0) {
 795             error_free(local_err);
 796         } else {
 797             error_report_err(local_err);
 798         }
 799     }
 800
 801 out:
 802     qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
 803     object_unref(OBJECT(client->ioc));
 804     g_free(client);
 805 }
 806
 807 static gboolean accept_client(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
 808 {
 809     QIOChannelSocket *cioc;
 810     PRHelperClient *prh;
 811
 812     cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
 813                                      NULL);
 814     if (!cioc) {
 815         return TRUE;
 816     }
 817
 818     prh = g_new(PRHelperClient, 1);
 819     prh->ioc = cioc;
 820     prh->fd = -1;
 821     prh->co = qemu_coroutine_create(prh_co_entry, prh);
 822     qemu_coroutine_enter(prh->co);
 823
 824     return TRUE;
 825 }
 826
 827 static void termsig_handler(int signum)
 828 {
 829     qatomic_cmpxchg(&state, RUNNING, TERMINATE);
 830     qemu_notify_event();
 831 }
 832
 833 static void close_server_socket(void)
 834 {
 835     assert(server_ioc);
 836
 837     g_source_remove(server_watch);
 838     server_watch = -1;
 839     object_unref(OBJECT(server_ioc));
 840     num_active_sockets--;
 841 }
 842
 843 #ifdef CONFIG_LIBCAP_NG
 844 static int drop_privileges(void)
 845 {
 846     /* clear all capabilities */
 847     capng_clear(CAPNG_SELECT_BOTH);
 848
 849     if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 850                      CAP_SYS_RAWIO) < 0) {
 851         return -1;
 852     }
 853
 854 #ifdef CONFIG_MPATH
 855     /* For /dev/mapper/control ioctls */
 856     if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 857                      CAP_SYS_ADMIN) < 0) {
 858         return -1;
 859     }
 860 #endif
 861
 862     /* Change user/group id, retaining the capabilities.  Because file descriptors
 863      * are passed via SCM_RIGHTS, we don't need supplementary groups (and in
 864      * fact the helper can run as "nobody").
 865      */
 866     if (capng_change_id(uid != -1 ? uid : getuid(),
 867                         gid != -1 ? gid : getgid(),
 868                         CAPNG_DROP_SUPP_GRP | CAPNG_CLEAR_BOUNDING)) {
 869         return -1;
 870     }
 871
 872     return 0;
 873 }
 874 #endif
 875
 876 int main(int argc, char **argv)
 877 {
 878     const char *sopt = "hVk:f:dT:u:g:vq";
 879     struct option lopt[] = {
 880         { "help", no_argument, NULL, 'h' },
 881         { "version", no_argument, NULL, 'V' },
 882         { "socket", required_argument, NULL, 'k' },
 883         { "pidfile", required_argument, NULL, 'f' },
 884         { "daemon", no_argument, NULL, 'd' },
 885         { "trace", required_argument, NULL, 'T' },
 886         { "user", required_argument, NULL, 'u' },
 887         { "group", required_argument, NULL, 'g' },
 888         { "verbose", no_argument, NULL, 'v' },
 889         { "quiet", no_argument, NULL, 'q' },
 890         { NULL, 0, NULL, 0 }
 891     };
 892     int opt_ind = 0;
 893     int loglevel = 1;
 894     int quiet = 0;
 895     int ch;
 896     Error *local_err = NULL;
 897     bool daemonize = false;
 898     bool pidfile_specified = false;
 899     bool socket_path_specified = false;
 900     unsigned socket_activation;
 901
 902     struct sigaction sa_sigterm;
 903     memset(&sa_sigterm, 0, sizeof(sa_sigterm));
 904     sa_sigterm.sa_handler = termsig_handler;
 905     sigaction(SIGTERM, &sa_sigterm, NULL);
 906     sigaction(SIGINT, &sa_sigterm, NULL);
 907     sigaction(SIGHUP, &sa_sigterm, NULL);
 908
 909     signal(SIGPIPE, SIG_IGN);
 910
 911     error_init(argv[0]);
 912     module_call_init(MODULE_INIT_TRACE);
 913     module_call_init(MODULE_INIT_QOM);
 914     qemu_add_opts(&qemu_trace_opts);
 915     qemu_init_exec_dir(argv[0]);
 916
 917     compute_default_paths();
 918
 919     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
 920         switch (ch) {
 921         case 'k':
 922             g_free(socket_path);
 923             socket_path = g_strdup(optarg);
 924             socket_path_specified = true;
 925             if (socket_path[0] != '/') {
 926                 error_report("socket path must be absolute");
 927                 exit(EXIT_FAILURE);
 928             }
 929             break;
 930         case 'f':
 931             g_free(pidfile);
 932             pidfile = g_strdup(optarg);
 933             pidfile_specified = true;
 934             break;
 935 #ifdef CONFIG_LIBCAP_NG
 936         case 'u': {
 937             unsigned long res;
 938             struct passwd *userinfo = getpwnam(optarg);
 939             if (userinfo) {
 940                 uid = userinfo->pw_uid;
 941             } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
 942                        (uid_t)res == res) {
 943                 uid = res;
 944             } else {
 945                 error_report("invalid user '%s'", optarg);
 946                 exit(EXIT_FAILURE);
 947             }
 948             break;
 949         }
 950         case 'g': {
 951             unsigned long res;
 952             struct group *groupinfo = getgrnam(optarg);
 953             if (groupinfo) {
 954                 gid = groupinfo->gr_gid;
 955             } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
 956                        (gid_t)res == res) {
 957                 gid = res;
 958             } else {
 959                 error_report("invalid group '%s'", optarg);
 960                 exit(EXIT_FAILURE);
 961             }
 962             break;
 963         }
 964 #else
 965         case 'u':
 966         case 'g':
 967             error_report("-%c not supported by this %s", ch, argv[0]);
 968             exit(1);
 969 #endif
 970         case 'd':
 971             daemonize = true;
 972             break;
 973         case 'q':
 974             quiet = 1;
 975             break;
 976         case 'v':
 977             ++loglevel;
 978             break;
 979         case 'T':
 980             trace_opt_parse(optarg);
 981             break;
 982         case 'V':
 983             version(argv[0]);
 984             exit(EXIT_SUCCESS);
 985             break;
 986         case 'h':
 987             usage(argv[0]);
 988             exit(EXIT_SUCCESS);
 989             break;
 990         case '?':
 991             error_report("Try `%s --help' for more information.", argv[0]);
 992             exit(EXIT_FAILURE);
 993         }
 994     }
 995
 996     /* set verbosity */
 997     noisy = !quiet && (loglevel >= 3);
 998     verbose = quiet ? 0 : MIN(loglevel, 3);
 999
1000     if (!trace_init_backends()) {
1001         exit(EXIT_FAILURE);
1002     }
1003     trace_init_file();
1004     qemu_set_log(LOG_TRACE);
1005
1006 #ifdef CONFIG_MPATH
1007     dm_init();
1008     multipath_pr_init();
1009 #endif
1010
1011     socket_activation = check_socket_activation();
1012     if (socket_activation == 0) {
1013         SocketAddress saddr;
1014         saddr = (SocketAddress){
1015             .type = SOCKET_ADDRESS_TYPE_UNIX,
1016             .u.q_unix.path = socket_path,
1017         };
1018         server_ioc = qio_channel_socket_new();
1019         if (qio_channel_socket_listen_sync(server_ioc, &saddr,
1020                                            1, &local_err) < 0) {
1021             object_unref(OBJECT(server_ioc));
1022             error_report_err(local_err);
1023             return 1;
1024         }
1025     } else {
1026         /* Using socket activation - check user didn't use -p etc. */
1027         if (socket_path_specified) {
1028             error_report("Unix socket can't be set when using socket activation");
1029             exit(EXIT_FAILURE);
1030         }
1031
1032         /* Can only listen on a single socket.  */
1033         if (socket_activation > 1) {
1034             error_report("%s does not support socket activation with LISTEN_FDS > 1",
1035                          argv[0]);
1036             exit(EXIT_FAILURE);
1037         }
1038         server_ioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD,
1039                                                &local_err);
1040         if (server_ioc == NULL) {
1041             error_reportf_err(local_err,
1042                               "Failed to use socket activation: ");
1043             exit(EXIT_FAILURE);
1044         }
1045     }
1046
1047     if (qemu_init_main_loop(&local_err)) {
1048         error_report_err(local_err);
1049         exit(EXIT_FAILURE);
1050     }
1051
1052     server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
1053                                          G_IO_IN,
1054                                          accept_client,
1055                                          NULL, NULL);
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     }
1063
1064     if ((daemonize || pidfile_specified) &&
1065         !qemu_write_pidfile(pidfile, &local_err)) {
1066         error_report_err(local_err);
1067         exit(EXIT_FAILURE);
1068     }
1069
1070 #ifdef CONFIG_LIBCAP_NG
1071     if (drop_privileges() < 0) {
1072         error_report("Failed to drop privileges: %s", strerror(errno));
1073         exit(EXIT_FAILURE);
1074     }
1075 #endif
1076
1077     state = RUNNING;
1078     do {
1079         main_loop_wait(false);
1080         if (state == TERMINATE) {
1081             state = TERMINATING;
1082             close_server_socket();
1083         }
1084     } while (num_active_sockets > 0);
1085
1086     exit(EXIT_SUCCESS);
1087 }