qga/guest-agent-commands.c

   1 /*
   2  * QEMU Guest Agent commands
   3  *
   4  * Copyright IBM Corp. 2011
   5  *
   6  * Authors:
   7  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include <glib.h>
  14
  15 #if defined(__linux__)
  16 #include <mntent.h>
  17 #include <linux/fs.h>
  18
  19 #if defined(__linux__) && defined(FIFREEZE)
  20 #define CONFIG_FSFREEZE
  21 #endif
  22 #endif
  23
  24 #include <sys/types.h>
  25 #include <sys/ioctl.h>
  26 #include "qga/guest-agent-core.h"
  27 #include "qga-qmp-commands.h"
  28 #include "qerror.h"
  29 #include "qemu-queue.h"
  30
  31 static GAState *ga_state;
  32
  33 /* Note: in some situations, like with the fsfreeze, logging may be
  34  * temporarilly disabled. if it is necessary that a command be able
  35  * to log for accounting purposes, check ga_logging_enabled() beforehand,
  36  * and use the QERR_QGA_LOGGING_DISABLED to generate an error
  37  */
  38 static void slog(const char *fmt, ...)
  39 {
  40     va_list ap;
  41
  42     va_start(ap, fmt);
  43     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
  44     va_end(ap);
  45 }
  46
  47 int64_t qmp_guest_sync(int64_t id, Error **errp)
  48 {
  49     return id;
  50 }
  51
  52 void qmp_guest_ping(Error **err)
  53 {
  54     slog("guest-ping called");
  55 }
  56
  57 struct GuestAgentInfo *qmp_guest_info(Error **err)
  58 {
  59     GuestAgentInfo *info = g_malloc0(sizeof(GuestAgentInfo));
  60
  61     info->version = g_strdup(QGA_VERSION);
  62
  63     return info;
  64 }
  65
  66 void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err)
  67 {
  68     int ret;
  69     const char *shutdown_flag;
  70
  71     slog("guest-shutdown called, mode: %s", mode);
  72     if (!has_mode || strcmp(mode, "powerdown") == 0) {
  73         shutdown_flag = "-P";
  74     } else if (strcmp(mode, "halt") == 0) {
  75         shutdown_flag = "-H";
  76     } else if (strcmp(mode, "reboot") == 0) {
  77         shutdown_flag = "-r";
  78     } else {
  79         error_set(err, QERR_INVALID_PARAMETER_VALUE, "mode",
  80                   "halt|powerdown|reboot");
  81         return;
  82     }
  83
  84     ret = fork();
  85     if (ret == 0) {
  86         /* child, start the shutdown */
  87         setsid();
  88         fclose(stdin);
  89         fclose(stdout);
  90         fclose(stderr);
  91
  92         ret = execl("/sbin/shutdown", "shutdown", shutdown_flag, "+0",
  93                     "hypervisor initiated shutdown", (char*)NULL);
  94         if (ret) {
  95             slog("guest-shutdown failed: %s", strerror(errno));
  96         }
  97         exit(!!ret);
  98     } else if (ret < 0) {
  99         error_set(err, QERR_UNDEFINED_ERROR);
 100     }
 101 }
 102
 103 typedef struct GuestFileHandle {
 104     uint64_t id;
 105     FILE *fh;
 106     QTAILQ_ENTRY(GuestFileHandle) next;
 107 } GuestFileHandle;
 108
 109 static struct {
 110     QTAILQ_HEAD(, GuestFileHandle) filehandles;
 111 } guest_file_state;
 112
 113 static void guest_file_handle_add(FILE *fh)
 114 {
 115     GuestFileHandle *gfh;
 116
 117     gfh = g_malloc0(sizeof(GuestFileHandle));
 118     gfh->id = fileno(fh);
 119     gfh->fh = fh;
 120     QTAILQ_INSERT_TAIL(&guest_file_state.filehandles, gfh, next);
 121 }
 122
 123 static GuestFileHandle *guest_file_handle_find(int64_t id)
 124 {
 125     GuestFileHandle *gfh;
 126
 127     QTAILQ_FOREACH(gfh, &guest_file_state.filehandles, next)
 128     {
 129         if (gfh->id == id) {
 130             return gfh;
 131         }
 132     }
 133
 134     return NULL;
 135 }
 136
 137 int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, Error **err)
 138 {
 139     FILE *fh;
 140     int fd;
 141     int64_t ret = -1;
 142
 143     if (!has_mode) {
 144         mode = "r";
 145     }
 146     slog("guest-file-open called, filepath: %s, mode: %s", path, mode);
 147     fh = fopen(path, mode);
 148     if (!fh) {
 149         error_set(err, QERR_OPEN_FILE_FAILED, path);
 150         return -1;
 151     }
 152
 153     /* set fd non-blocking to avoid common use cases (like reading from a
 154      * named pipe) from hanging the agent
 155      */
 156     fd = fileno(fh);
 157     ret = fcntl(fd, F_GETFL);
 158     ret = fcntl(fd, F_SETFL, ret | O_NONBLOCK);
 159     if (ret == -1) {
 160         error_set(err, QERR_QGA_COMMAND_FAILED, "fcntl() failed");
 161         fclose(fh);
 162         return -1;
 163     }
 164
 165     guest_file_handle_add(fh);
 166     slog("guest-file-open, handle: %d", fd);
 167     return fd;
 168 }
 169
 170 void qmp_guest_file_close(int64_t handle, Error **err)
 171 {
 172     GuestFileHandle *gfh = guest_file_handle_find(handle);
 173     int ret;
 174
 175     slog("guest-file-close called, handle: %ld", handle);
 176     if (!gfh) {
 177         error_set(err, QERR_FD_NOT_FOUND, "handle");
 178         return;
 179     }
 180
 181     ret = fclose(gfh->fh);
 182     if (ret == -1) {
 183         error_set(err, QERR_QGA_COMMAND_FAILED, "fclose() failed");
 184         return;
 185     }
 186
 187     QTAILQ_REMOVE(&guest_file_state.filehandles, gfh, next);
 188     g_free(gfh);
 189 }
 190
 191 struct GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
 192                                           int64_t count, Error **err)
 193 {
 194     GuestFileHandle *gfh = guest_file_handle_find(handle);
 195     GuestFileRead *read_data = NULL;
 196     guchar *buf;
 197     FILE *fh;
 198     size_t read_count;
 199
 200     if (!gfh) {
 201         error_set(err, QERR_FD_NOT_FOUND, "handle");
 202         return NULL;
 203     }
 204
 205     if (!has_count) {
 206         count = QGA_READ_COUNT_DEFAULT;
 207     } else if (count < 0) {
 208         error_set(err, QERR_INVALID_PARAMETER, "count");
 209         return NULL;
 210     }
 211
 212     fh = gfh->fh;
 213     buf = g_malloc0(count+1);
 214     read_count = fread(buf, 1, count, fh);
 215     if (ferror(fh)) {
 216         slog("guest-file-read failed, handle: %ld", handle);
 217         error_set(err, QERR_QGA_COMMAND_FAILED, "fread() failed");
 218     } else {
 219         buf[read_count] = 0;
 220         read_data = g_malloc0(sizeof(GuestFileRead));
 221         read_data->count = read_count;
 222         read_data->eof = feof(fh);
 223         if (read_count) {
 224             read_data->buf_b64 = g_base64_encode(buf, read_count);
 225         }
 226     }
 227     g_free(buf);
 228     clearerr(fh);
 229
 230     return read_data;
 231 }
 232
 233 GuestFileWrite *qmp_guest_file_write(int64_t handle, const char *buf_b64,
 234                                      bool has_count, int64_t count, Error **err)
 235 {
 236     GuestFileWrite *write_data = NULL;
 237     guchar *buf;
 238     gsize buf_len;
 239     int write_count;
 240     GuestFileHandle *gfh = guest_file_handle_find(handle);
 241     FILE *fh;
 242
 243     if (!gfh) {
 244         error_set(err, QERR_FD_NOT_FOUND, "handle");
 245         return NULL;
 246     }
 247
 248     fh = gfh->fh;
 249     buf = g_base64_decode(buf_b64, &buf_len);
 250
 251     if (!has_count) {
 252         count = buf_len;
 253     } else if (count < 0 || count > buf_len) {
 254         g_free(buf);
 255         error_set(err, QERR_INVALID_PARAMETER, "count");
 256         return NULL;
 257     }
 258
 259     write_count = fwrite(buf, 1, count, fh);
 260     if (ferror(fh)) {
 261         slog("guest-file-write failed, handle: %ld", handle);
 262         error_set(err, QERR_QGA_COMMAND_FAILED, "fwrite() error");
 263     } else {
 264         write_data = g_malloc0(sizeof(GuestFileWrite));
 265         write_data->count = write_count;
 266         write_data->eof = feof(fh);
 267     }
 268     g_free(buf);
 269     clearerr(fh);
 270
 271     return write_data;
 272 }
 273
 274 struct GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
 275                                           int64_t whence, Error **err)
 276 {
 277     GuestFileHandle *gfh = guest_file_handle_find(handle);
 278     GuestFileSeek *seek_data = NULL;
 279     FILE *fh;
 280     int ret;
 281
 282     if (!gfh) {
 283         error_set(err, QERR_FD_NOT_FOUND, "handle");
 284         return NULL;
 285     }
 286
 287     fh = gfh->fh;
 288     ret = fseek(fh, offset, whence);
 289     if (ret == -1) {
 290         error_set(err, QERR_QGA_COMMAND_FAILED, strerror(errno));
 291     } else {
 292         seek_data = g_malloc0(sizeof(GuestFileRead));
 293         seek_data->position = ftell(fh);
 294         seek_data->eof = feof(fh);
 295     }
 296     clearerr(fh);
 297
 298     return seek_data;
 299 }
 300
 301 void qmp_guest_file_flush(int64_t handle, Error **err)
 302 {
 303     GuestFileHandle *gfh = guest_file_handle_find(handle);
 304     FILE *fh;
 305     int ret;
 306
 307     if (!gfh) {
 308         error_set(err, QERR_FD_NOT_FOUND, "handle");
 309         return;
 310     }
 311
 312     fh = gfh->fh;
 313     ret = fflush(fh);
 314     if (ret == EOF) {
 315         error_set(err, QERR_QGA_COMMAND_FAILED, strerror(errno));
 316     }
 317 }
 318
 319 static void guest_file_init(void)
 320 {
 321     QTAILQ_INIT(&guest_file_state.filehandles);
 322 }
 323
 324 #if defined(CONFIG_FSFREEZE)
 325 static void disable_logging(void)
 326 {
 327     ga_disable_logging(ga_state);
 328 }
 329
 330 static void enable_logging(void)
 331 {
 332     ga_enable_logging(ga_state);
 333 }
 334
 335 typedef struct GuestFsfreezeMount {
 336     char *dirname;
 337     char *devtype;
 338     QTAILQ_ENTRY(GuestFsfreezeMount) next;
 339 } GuestFsfreezeMount;
 340
 341 struct {
 342     GuestFsfreezeStatus status;
 343     QTAILQ_HEAD(, GuestFsfreezeMount) mount_list;
 344 } guest_fsfreeze_state;
 345
 346 /*
 347  * Walk the mount table and build a list of local file systems
 348  */
 349 static int guest_fsfreeze_build_mount_list(void)
 350 {
 351     struct mntent *ment;
 352     GuestFsfreezeMount *mount, *temp;
 353     char const *mtab = MOUNTED;
 354     FILE *fp;
 355
 356     QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
 357         QTAILQ_REMOVE(&guest_fsfreeze_state.mount_list, mount, next);
 358         g_free(mount->dirname);
 359         g_free(mount->devtype);
 360         g_free(mount);
 361     }
 362
 363     fp = setmntent(mtab, "r");
 364     if (!fp) {
 365         g_warning("fsfreeze: unable to read mtab");
 366         return -1;
 367     }
 368
 369     while ((ment = getmntent(fp))) {
 370         /*
 371          * An entry which device name doesn't start with a '/' is
 372          * either a dummy file system or a network file system.
 373          * Add special handling for smbfs and cifs as is done by
 374          * coreutils as well.
 375          */
 376         if ((ment->mnt_fsname[0] != '/') ||
 377             (strcmp(ment->mnt_type, "smbfs") == 0) ||
 378             (strcmp(ment->mnt_type, "cifs") == 0)) {
 379             continue;
 380         }
 381
 382         mount = g_malloc0(sizeof(GuestFsfreezeMount));
 383         mount->dirname = g_strdup(ment->mnt_dir);
 384         mount->devtype = g_strdup(ment->mnt_type);
 385
 386         QTAILQ_INSERT_TAIL(&guest_fsfreeze_state.mount_list, mount, next);
 387     }
 388
 389     endmntent(fp);
 390
 391     return 0;
 392 }
 393
 394 /*
 395  * Return status of freeze/thaw
 396  */
 397 GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **err)
 398 {
 399     return guest_fsfreeze_state.status;
 400 }
 401
 402 /*
 403  * Walk list of mounted file systems in the guest, and freeze the ones which
 404  * are real local file systems.
 405  */
 406 int64_t qmp_guest_fsfreeze_freeze(Error **err)
 407 {
 408     int ret = 0, i = 0;
 409     struct GuestFsfreezeMount *mount, *temp;
 410     int fd;
 411     char err_msg[512];
 412
 413     slog("guest-fsfreeze called");
 414
 415     if (guest_fsfreeze_state.status == GUEST_FSFREEZE_STATUS_FROZEN) {
 416         return 0;
 417     }
 418
 419     ret = guest_fsfreeze_build_mount_list();
 420     if (ret < 0) {
 421         return ret;
 422     }
 423
 424     /* cannot risk guest agent blocking itself on a write in this state */
 425     disable_logging();
 426
 427     QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
 428         fd = qemu_open(mount->dirname, O_RDONLY);
 429         if (fd == -1) {
 430             sprintf(err_msg, "failed to open %s, %s", mount->dirname, strerror(errno));
 431             error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
 432             goto error;
 433         }
 434
 435         /* we try to cull filesytems we know won't work in advance, but other
 436          * filesytems may not implement fsfreeze for less obvious reasons.
 437          * these will report EOPNOTSUPP, so we simply ignore them. when
 438          * thawing, these filesystems will return an EINVAL instead, due to
 439          * not being in a frozen state. Other filesystem-specific
 440          * errors may result in EINVAL, however, so the user should check the
 441          * number * of filesystems returned here against those returned by the
 442          * thaw operation to determine whether everything completed
 443          * successfully
 444          */
 445         ret = ioctl(fd, FIFREEZE);
 446         if (ret < 0 && errno != EOPNOTSUPP) {
 447             sprintf(err_msg, "failed to freeze %s, %s", mount->dirname, strerror(errno));
 448             error_set(err, QERR_QGA_COMMAND_FAILED, err_msg);
 449             close(fd);
 450             goto error;
 451         }
 452         close(fd);
 453
 454         i++;
 455     }
 456
 457     guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_FROZEN;
 458     return i;
 459
 460 error:
 461     if (i > 0) {
 462         qmp_guest_fsfreeze_thaw(NULL);
 463     }
 464     return 0;
 465 }
 466
 467 /*
 468  * Walk list of frozen file systems in the guest, and thaw them.
 469  */
 470 int64_t qmp_guest_fsfreeze_thaw(Error **err)
 471 {
 472     int ret;
 473     GuestFsfreezeMount *mount, *temp;
 474     int fd, i = 0;
 475     bool has_error = false;
 476
 477     QTAILQ_FOREACH_SAFE(mount, &guest_fsfreeze_state.mount_list, next, temp) {
 478         fd = qemu_open(mount->dirname, O_RDONLY);
 479         if (fd == -1) {
 480             has_error = true;
 481             continue;
 482         }
 483         ret = ioctl(fd, FITHAW);
 484         if (ret < 0 && errno != EOPNOTSUPP && errno != EINVAL) {
 485             has_error = true;
 486             close(fd);
 487             continue;
 488         }
 489         close(fd);
 490         i++;
 491     }
 492
 493     if (has_error) {
 494         guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_ERROR;
 495     } else {
 496         guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED;
 497     }
 498     enable_logging();
 499     return i;
 500 }
 501
 502 static void guest_fsfreeze_init(void)
 503 {
 504     guest_fsfreeze_state.status = GUEST_FSFREEZE_STATUS_THAWED;
 505     QTAILQ_INIT(&guest_fsfreeze_state.mount_list);
 506 }
 507
 508 static void guest_fsfreeze_cleanup(void)
 509 {
 510     int64_t ret;
 511     Error *err = NULL;
 512
 513     if (guest_fsfreeze_state.status == GUEST_FSFREEZE_STATUS_FROZEN) {
 514         ret = qmp_guest_fsfreeze_thaw(&err);
 515         if (ret < 0 || err) {
 516             slog("failed to clean up frozen filesystems");
 517         }
 518     }
 519 }
 520 #else
 521 /*
 522  * Return status of freeze/thaw
 523  */
 524 GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **err)
 525 {
 526     error_set(err, QERR_UNSUPPORTED);
 527
 528     return 0;
 529 }
 530
 531 /*
 532  * Walk list of mounted file systems in the guest, and freeze the ones which
 533  * are real local file systems.
 534  */
 535 int64_t qmp_guest_fsfreeze_freeze(Error **err)
 536 {
 537     error_set(err, QERR_UNSUPPORTED);
 538
 539     return 0;
 540 }
 541
 542 /*
 543  * Walk list of frozen file systems in the guest, and thaw them.
 544  */
 545 int64_t qmp_guest_fsfreeze_thaw(Error **err)
 546 {
 547     error_set(err, QERR_UNSUPPORTED);
 548
 549     return 0;
 550 }
 551 #endif
 552
 553 /* register init/cleanup routines for stateful command groups */
 554 void ga_command_state_init(GAState *s, GACommandState *cs)
 555 {
 556     ga_state = s;
 557 #if defined(CONFIG_FSFREEZE)
 558     ga_command_state_add(cs, guest_fsfreeze_init, guest_fsfreeze_cleanup);
 559 #endif
 560     ga_command_state_add(cs, guest_file_init, NULL);
 561 }