qga/commands.c

   1 /*
   2  * QEMU Guest Agent common/cross-platform command implementations
   3  *
   4  * Copyright IBM Corp. 2012
   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 "qemu/osdep.h"
  14 #include "qemu/units.h"
  15 #include "guest-agent-core.h"
  16 #include "qga-qapi-commands.h"
  17 #include "qapi/error.h"
  18 #include "qapi/qmp/qerror.h"
  19 #include "qemu/base64.h"
  20 #include "qemu/cutils.h"
  21 #include "qemu/atomic.h"
  22 #include "commands-common.h"
  23
  24 /* Maximum captured guest-exec out_data/err_data - 16MB */
  25 #define GUEST_EXEC_MAX_OUTPUT (16 * 1024 * 1024)
  26 /* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
  27 #define GUEST_EXEC_IO_SIZE (4 * 1024)
  28 /*
  29  * Maximum file size to read - 48MB
  30  *
  31  * (48MB + Base64 3:4 overhead = JSON parser 64 MB limit)
  32  */
  33 #define GUEST_FILE_READ_COUNT_MAX (48 * MiB)
  34
  35 /* Note: in some situations, like with the fsfreeze, logging may be
  36  * temporarilly disabled. if it is necessary that a command be able
  37  * to log for accounting purposes, check ga_logging_enabled() beforehand,
  38  * and use the QERR_QGA_LOGGING_DISABLED to generate an error
  39  */
  40 void slog(const gchar *fmt, ...)
  41 {
  42     va_list ap;
  43
  44     va_start(ap, fmt);
  45     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
  46     va_end(ap);
  47 }
  48
  49 int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
  50 {
  51     ga_set_response_delimited(ga_state);
  52     return id;
  53 }
  54
  55 int64_t qmp_guest_sync(int64_t id, Error **errp)
  56 {
  57     return id;
  58 }
  59
  60 void qmp_guest_ping(Error **errp)
  61 {
  62     slog("guest-ping called");
  63 }
  64
  65 static void qmp_command_info(const QmpCommand *cmd, void *opaque)
  66 {
  67     GuestAgentInfo *info = opaque;
  68     GuestAgentCommandInfo *cmd_info;
  69
  70     cmd_info = g_new0(GuestAgentCommandInfo, 1);
  71     cmd_info->name = g_strdup(qmp_command_name(cmd));
  72     cmd_info->enabled = qmp_command_is_enabled(cmd);
  73     cmd_info->success_response = qmp_has_success_response(cmd);
  74
  75     QAPI_LIST_PREPEND(info->supported_commands, cmd_info);
  76 }
  77
  78 struct GuestAgentInfo *qmp_guest_info(Error **errp)
  79 {
  80     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
  81
  82     info->version = g_strdup(QEMU_VERSION);
  83     qmp_for_each_command(&ga_commands, qmp_command_info, info);
  84     return info;
  85 }
  86
  87 struct GuestExecIOData {
  88     guchar *data;
  89     gsize size;
  90     gsize length;
  91     bool closed;
  92     bool truncated;
  93     const char *name;
  94 };
  95 typedef struct GuestExecIOData GuestExecIOData;
  96
  97 struct GuestExecInfo {
  98     GPid pid;
  99     int64_t pid_numeric;
 100     gint status;
 101     bool has_output;
 102     bool finished;
 103     GuestExecIOData in;
 104     GuestExecIOData out;
 105     GuestExecIOData err;
 106     QTAILQ_ENTRY(GuestExecInfo) next;
 107 };
 108 typedef struct GuestExecInfo GuestExecInfo;
 109
 110 static struct {
 111     QTAILQ_HEAD(, GuestExecInfo) processes;
 112 } guest_exec_state = {
 113     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 114 };
 115
 116 static int64_t gpid_to_int64(GPid pid)
 117 {
 118 #ifdef G_OS_WIN32
 119     return GetProcessId(pid);
 120 #else
 121     return (int64_t)pid;
 122 #endif
 123 }
 124
 125 static GuestExecInfo *guest_exec_info_add(GPid pid)
 126 {
 127     GuestExecInfo *gei;
 128
 129     gei = g_new0(GuestExecInfo, 1);
 130     gei->pid = pid;
 131     gei->pid_numeric = gpid_to_int64(pid);
 132     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
 133
 134     return gei;
 135 }
 136
 137 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
 138 {
 139     GuestExecInfo *gei;
 140
 141     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
 142         if (gei->pid_numeric == pid_numeric) {
 143             return gei;
 144         }
 145     }
 146
 147     return NULL;
 148 }
 149
 150 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **errp)
 151 {
 152     GuestExecInfo *gei;
 153     GuestExecStatus *ges;
 154
 155     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
 156
 157     gei = guest_exec_info_find(pid);
 158     if (gei == NULL) {
 159         error_setg(errp, QERR_INVALID_PARAMETER, "pid");
 160         return NULL;
 161     }
 162
 163     ges = g_new0(GuestExecStatus, 1);
 164
 165     bool finished = qatomic_mb_read(&gei->finished);
 166
 167     /* need to wait till output channels are closed
 168      * to be sure we captured all output at this point */
 169     if (gei->has_output) {
 170         finished = finished && qatomic_mb_read(&gei->out.closed);
 171         finished = finished && qatomic_mb_read(&gei->err.closed);
 172     }
 173
 174     ges->exited = finished;
 175     if (finished) {
 176         /* Glib has no portable way to parse exit status.
 177          * On UNIX, we can get either exit code from normal termination
 178          * or signal number.
 179          * On Windows, it is either the same exit code or the exception
 180          * value for an unhandled exception that caused the process
 181          * to terminate.
 182          * See MSDN for GetExitCodeProcess() and ntstatus.h for possible
 183          * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
 184          * References:
 185          *   https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
 186          *   https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
 187          */
 188 #ifdef G_OS_WIN32
 189         /* Additionally WIN32 does not provide any additional information
 190          * on whether the child exited or terminated via signal.
 191          * We use this simple range check to distinguish application exit code
 192          * (usually value less then 256) and unhandled exception code with
 193          * ntstatus (always value greater then 0xC0000005). */
 194         if ((uint32_t)gei->status < 0xC0000000U) {
 195             ges->has_exitcode = true;
 196             ges->exitcode = gei->status;
 197         } else {
 198             ges->has_signal = true;
 199             ges->signal = gei->status;
 200         }
 201 #else
 202         if (WIFEXITED(gei->status)) {
 203             ges->has_exitcode = true;
 204             ges->exitcode = WEXITSTATUS(gei->status);
 205         } else if (WIFSIGNALED(gei->status)) {
 206             ges->has_signal = true;
 207             ges->signal = WTERMSIG(gei->status);
 208         }
 209 #endif
 210         if (gei->out.length > 0) {
 211             ges->has_out_data = true;
 212             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
 213             g_free(gei->out.data);
 214             ges->has_out_truncated = gei->out.truncated;
 215         }
 216
 217         if (gei->err.length > 0) {
 218             ges->has_err_data = true;
 219             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
 220             g_free(gei->err.data);
 221             ges->has_err_truncated = gei->err.truncated;
 222         }
 223
 224         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
 225         g_free(gei);
 226     }
 227
 228     return ges;
 229 }
 230
 231 /* Get environment variables or arguments array for execve(). */
 232 static char **guest_exec_get_args(const strList *entry, bool log)
 233 {
 234     const strList *it;
 235     int count = 1, i = 0;  /* reserve for NULL terminator */
 236     char **args;
 237     char *str; /* for logging array of arguments */
 238     size_t str_size = 1;
 239
 240     for (it = entry; it != NULL; it = it->next) {
 241         count++;
 242         str_size += 1 + strlen(it->value);
 243     }
 244
 245     str = g_malloc(str_size);
 246     *str = 0;
 247     args = g_malloc(count * sizeof(char *));
 248     for (it = entry; it != NULL; it = it->next) {
 249         args[i++] = it->value;
 250         pstrcat(str, str_size, it->value);
 251         if (it->next) {
 252             pstrcat(str, str_size, " ");
 253         }
 254     }
 255     args[i] = NULL;
 256
 257     if (log) {
 258         slog("guest-exec called: \"%s\"", str);
 259     }
 260     g_free(str);
 261
 262     return args;
 263 }
 264
 265 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
 266 {
 267     GuestExecInfo *gei = (GuestExecInfo *)data;
 268
 269     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
 270             (int32_t)gpid_to_int64(pid), (uint32_t)status);
 271
 272     gei->status = status;
 273     qatomic_mb_set(&gei->finished, true);
 274
 275     g_spawn_close_pid(pid);
 276 }
 277
 278 /** Reset ignored signals back to default. */
 279 static void guest_exec_task_setup(gpointer data)
 280 {
 281 #if !defined(G_OS_WIN32)
 282     struct sigaction sigact;
 283
 284     memset(&sigact, 0, sizeof(struct sigaction));
 285     sigact.sa_handler = SIG_DFL;
 286
 287     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 288         slog("sigaction() failed to reset child process's SIGPIPE: %s",
 289              strerror(errno));
 290     }
 291 #endif
 292 }
 293
 294 static gboolean guest_exec_input_watch(GIOChannel *ch,
 295         GIOCondition cond, gpointer p_)
 296 {
 297     GuestExecIOData *p = (GuestExecIOData *)p_;
 298     gsize bytes_written = 0;
 299     GIOStatus status;
 300     GError *gerr = NULL;
 301
 302     /* nothing left to write */
 303     if (p->size == p->length) {
 304         goto done;
 305     }
 306
 307     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
 308             p->size - p->length, &bytes_written, &gerr);
 309
 310     /* can be not 0 even if not G_IO_STATUS_NORMAL */
 311     if (bytes_written != 0) {
 312         p->length += bytes_written;
 313     }
 314
 315     /* continue write, our callback will be called again */
 316     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
 317         return true;
 318     }
 319
 320     if (gerr) {
 321         g_warning("qga: i/o error writing to input_data channel: %s",
 322                 gerr->message);
 323         g_error_free(gerr);
 324     }
 325
 326 done:
 327     g_io_channel_shutdown(ch, true, NULL);
 328     g_io_channel_unref(ch);
 329     qatomic_mb_set(&p->closed, true);
 330     g_free(p->data);
 331
 332     return false;
 333 }
 334
 335 static gboolean guest_exec_output_watch(GIOChannel *ch,
 336         GIOCondition cond, gpointer p_)
 337 {
 338     GuestExecIOData *p = (GuestExecIOData *)p_;
 339     gsize bytes_read;
 340     GIOStatus gstatus;
 341
 342     if (cond == G_IO_HUP || cond == G_IO_ERR) {
 343         goto close;
 344     }
 345
 346     if (p->size == p->length) {
 347         gpointer t = NULL;
 348         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
 349             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
 350         }
 351         if (t == NULL) {
 352             /* ignore truncated output */
 353             gchar buf[GUEST_EXEC_IO_SIZE];
 354
 355             p->truncated = true;
 356             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
 357                                               &bytes_read, NULL);
 358             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 359                 goto close;
 360             }
 361
 362             return true;
 363         }
 364         p->size += GUEST_EXEC_IO_SIZE;
 365         p->data = t;
 366     }
 367
 368     /* Calling read API once.
 369      * On next available data our callback will be called again */
 370     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
 371             p->size - p->length, &bytes_read, NULL);
 372     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 373         goto close;
 374     }
 375
 376     p->length += bytes_read;
 377
 378     return true;
 379
 380 close:
 381     g_io_channel_shutdown(ch, true, NULL);
 382     g_io_channel_unref(ch);
 383     qatomic_mb_set(&p->closed, true);
 384     return false;
 385 }
 386
 387 GuestExec *qmp_guest_exec(const char *path,
 388                        bool has_arg, strList *arg,
 389                        bool has_env, strList *env,
 390                        bool has_input_data, const char *input_data,
 391                        bool has_capture_output, bool capture_output,
 392                        Error **errp)
 393 {
 394     GPid pid;
 395     GuestExec *ge = NULL;
 396     GuestExecInfo *gei;
 397     char **argv, **envp;
 398     strList arglist;
 399     gboolean ret;
 400     GError *gerr = NULL;
 401     gint in_fd, out_fd, err_fd;
 402     GIOChannel *in_ch, *out_ch, *err_ch;
 403     GSpawnFlags flags;
 404     bool has_output = (has_capture_output && capture_output);
 405     g_autofree uint8_t *input = NULL;
 406     size_t ninput = 0;
 407
 408     arglist.value = (char *)path;
 409     arglist.next = has_arg ? arg : NULL;
 410
 411     if (has_input_data) {
 412         input = qbase64_decode(input_data, -1, &ninput, errp);
 413         if (!input) {
 414             return NULL;
 415         }
 416     }
 417
 418     argv = guest_exec_get_args(&arglist, true);
 419     envp = has_env ? guest_exec_get_args(env, false) : NULL;
 420
 421     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD |
 422         G_SPAWN_SEARCH_PATH_FROM_ENVP;
 423     if (!has_output) {
 424         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
 425     }
 426
 427     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
 428             guest_exec_task_setup, NULL, &pid, has_input_data ? &in_fd : NULL,
 429             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
 430     if (!ret) {
 431         error_setg(errp, QERR_QGA_COMMAND_FAILED, gerr->message);
 432         g_error_free(gerr);
 433         goto done;
 434     }
 435
 436     ge = g_new0(GuestExec, 1);
 437     ge->pid = gpid_to_int64(pid);
 438
 439     gei = guest_exec_info_add(pid);
 440     gei->has_output = has_output;
 441     g_child_watch_add(pid, guest_exec_child_watch, gei);
 442
 443     if (has_input_data) {
 444         gei->in.data = g_steal_pointer(&input);
 445         gei->in.size = ninput;
 446 #ifdef G_OS_WIN32
 447         in_ch = g_io_channel_win32_new_fd(in_fd);
 448 #else
 449         in_ch = g_io_channel_unix_new(in_fd);
 450 #endif
 451         g_io_channel_set_encoding(in_ch, NULL, NULL);
 452         g_io_channel_set_buffered(in_ch, false);
 453         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
 454         g_io_channel_set_close_on_unref(in_ch, true);
 455         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
 456     }
 457
 458     if (has_output) {
 459 #ifdef G_OS_WIN32
 460         out_ch = g_io_channel_win32_new_fd(out_fd);
 461         err_ch = g_io_channel_win32_new_fd(err_fd);
 462 #else
 463         out_ch = g_io_channel_unix_new(out_fd);
 464         err_ch = g_io_channel_unix_new(err_fd);
 465 #endif
 466         g_io_channel_set_encoding(out_ch, NULL, NULL);
 467         g_io_channel_set_encoding(err_ch, NULL, NULL);
 468         g_io_channel_set_buffered(out_ch, false);
 469         g_io_channel_set_buffered(err_ch, false);
 470         g_io_channel_set_close_on_unref(out_ch, true);
 471         g_io_channel_set_close_on_unref(err_ch, true);
 472         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
 473                 guest_exec_output_watch, &gei->out);
 474         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
 475                 guest_exec_output_watch, &gei->err);
 476     }
 477
 478 done:
 479     g_free(argv);
 480     g_free(envp);
 481
 482     return ge;
 483 }
 484
 485 /* Convert GuestFileWhence (either a raw integer or an enum value) into
 486  * the guest's SEEK_ constants.  */
 487 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
 488 {
 489     /*
 490      * Exploit the fact that we picked values to match QGA_SEEK_*;
 491      * however, we have to use a temporary variable since the union
 492      * members may have different size.
 493      */
 494     if (whence->type == QTYPE_QSTRING) {
 495         int value = whence->u.name;
 496         whence->type = QTYPE_QNUM;
 497         whence->u.value = value;
 498     }
 499     switch (whence->u.value) {
 500     case QGA_SEEK_SET:
 501         return SEEK_SET;
 502     case QGA_SEEK_CUR:
 503         return SEEK_CUR;
 504     case QGA_SEEK_END:
 505         return SEEK_END;
 506     }
 507     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
 508     return -1;
 509 }
 510
 511 GuestHostName *qmp_guest_get_host_name(Error **errp)
 512 {
 513     GuestHostName *result = NULL;
 514     g_autofree char *hostname = qemu_get_host_name(errp);
 515
 516     /*
 517      * We want to avoid using g_get_host_name() because that
 518      * caches the result and we wouldn't reflect changes in the
 519      * host name.
 520      */
 521
 522     if (!hostname) {
 523         hostname = g_strdup("localhost");
 524     }
 525
 526     result = g_new0(GuestHostName, 1);
 527     result->host_name = g_steal_pointer(&hostname);
 528     return result;
 529 }
 530
 531 GuestTimezone *qmp_guest_get_timezone(Error **errp)
 532 {
 533     GuestTimezone *info = NULL;
 534     GTimeZone *tz = NULL;
 535     gint64 now = 0;
 536     gint32 intv = 0;
 537     gchar const *name = NULL;
 538
 539     info = g_new0(GuestTimezone, 1);
 540     tz = g_time_zone_new_local();
 541     if (tz == NULL) {
 542         error_setg(errp, QERR_QGA_COMMAND_FAILED,
 543                    "Couldn't retrieve local timezone");
 544         goto error;
 545     }
 546
 547     now = g_get_real_time() / G_USEC_PER_SEC;
 548     intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
 549     info->offset = g_time_zone_get_offset(tz, intv);
 550     name = g_time_zone_get_abbreviation(tz, intv);
 551     if (name != NULL) {
 552         info->has_zone = true;
 553         info->zone = g_strdup(name);
 554     }
 555     g_time_zone_unref(tz);
 556
 557     return info;
 558
 559 error:
 560     g_free(info);
 561     return NULL;
 562 }
 563
 564 GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
 565                                    int64_t count, Error **errp)
 566 {
 567     GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
 568     GuestFileRead *read_data;
 569
 570     if (!gfh) {
 571         return NULL;
 572     }
 573     if (!has_count) {
 574         count = QGA_READ_COUNT_DEFAULT;
 575     } else if (count < 0 || count > GUEST_FILE_READ_COUNT_MAX) {
 576         error_setg(errp, "value '%" PRId64 "' is invalid for argument count",
 577                    count);
 578         return NULL;
 579     }
 580
 581     read_data = guest_file_read_unsafe(gfh, count, errp);
 582     if (!read_data) {
 583         slog("guest-file-write failed, handle: %" PRId64, handle);
 584     }
 585
 586     return read_data;
 587 }