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