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 "commands-common.h"
  22
  23 /* Maximum captured guest-exec out_data/err_data - 16MB */
  24 #define GUEST_EXEC_MAX_OUTPUT (16 * 1024 * 1024)
  25 /* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
  26 #define GUEST_EXEC_IO_SIZE (4 * 1024)
  27 /*
  28  * Maximum file size to read - 48MB
  29  *
  30  * (48MB + Base64 3:4 overhead = JSON parser 64 MB limit)
  31  */
  32 #define GUEST_FILE_READ_COUNT_MAX (48 * MiB)
  33
  34 /* Note: in some situations, like with the fsfreeze, logging may be
  35  * temporarily disabled. if it is necessary that a command be able
  36  * to log for accounting purposes, check ga_logging_enabled() beforehand.
  37  */
  38 void slog(const gchar *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_delimited(int64_t id, Error **errp)
  48 {
  49     ga_set_response_delimited(ga_state);
  50     return id;
  51 }
  52
  53 int64_t qmp_guest_sync(int64_t id, Error **errp)
  54 {
  55     return id;
  56 }
  57
  58 void qmp_guest_ping(Error **errp)
  59 {
  60     slog("guest-ping called");
  61 }
  62
  63 static void qmp_command_info(const QmpCommand *cmd, void *opaque)
  64 {
  65     GuestAgentInfo *info = opaque;
  66     GuestAgentCommandInfo *cmd_info;
  67
  68     cmd_info = g_new0(GuestAgentCommandInfo, 1);
  69     cmd_info->name = g_strdup(qmp_command_name(cmd));
  70     cmd_info->enabled = qmp_command_is_enabled(cmd);
  71     cmd_info->success_response = qmp_has_success_response(cmd);
  72
  73     QAPI_LIST_PREPEND(info->supported_commands, cmd_info);
  74 }
  75
  76 struct GuestAgentInfo *qmp_guest_info(Error **errp)
  77 {
  78     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
  79
  80     info->version = g_strdup(QEMU_VERSION);
  81     qmp_for_each_command(&ga_commands, qmp_command_info, info);
  82     return info;
  83 }
  84
  85 struct GuestExecIOData {
  86     guchar *data;
  87     gsize size;
  88     gsize length;
  89     bool closed;
  90     bool truncated;
  91     const char *name;
  92 };
  93 typedef struct GuestExecIOData GuestExecIOData;
  94
  95 struct GuestExecInfo {
  96     GPid pid;
  97     int64_t pid_numeric;
  98     gint status;
  99     bool has_output;
 100     bool finished;
 101     GuestExecIOData in;
 102     GuestExecIOData out;
 103     GuestExecIOData err;
 104     QTAILQ_ENTRY(GuestExecInfo) next;
 105 };
 106 typedef struct GuestExecInfo GuestExecInfo;
 107
 108 static struct {
 109     QTAILQ_HEAD(, GuestExecInfo) processes;
 110 } guest_exec_state = {
 111     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 112 };
 113
 114 static int64_t gpid_to_int64(GPid pid)
 115 {
 116 #ifdef G_OS_WIN32
 117     return GetProcessId(pid);
 118 #else
 119     return (int64_t)pid;
 120 #endif
 121 }
 122
 123 static GuestExecInfo *guest_exec_info_add(GPid pid)
 124 {
 125     GuestExecInfo *gei;
 126
 127     gei = g_new0(GuestExecInfo, 1);
 128     gei->pid = pid;
 129     gei->pid_numeric = gpid_to_int64(pid);
 130     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
 131
 132     return gei;
 133 }
 134
 135 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
 136 {
 137     GuestExecInfo *gei;
 138
 139     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
 140         if (gei->pid_numeric == pid_numeric) {
 141             return gei;
 142         }
 143     }
 144
 145     return NULL;
 146 }
 147
 148 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **errp)
 149 {
 150     GuestExecInfo *gei;
 151     GuestExecStatus *ges;
 152
 153     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
 154
 155     gei = guest_exec_info_find(pid);
 156     if (gei == NULL) {
 157         error_setg(errp, "PID " PRId64 " does not exist");
 158         return NULL;
 159     }
 160
 161     ges = g_new0(GuestExecStatus, 1);
 162
 163     bool finished = gei->finished;
 164
 165     /* need to wait till output channels are closed
 166      * to be sure we captured all output at this point */
 167     if (gei->has_output) {
 168         finished &= gei->out.closed && gei->err.closed;
 169     }
 170
 171     ges->exited = finished;
 172     if (finished) {
 173         /* Glib has no portable way to parse exit status.
 174          * On UNIX, we can get either exit code from normal termination
 175          * or signal number.
 176          * On Windows, it is either the same exit code or the exception
 177          * value for an unhandled exception that caused the process
 178          * to terminate.
 179          * See MSDN for GetExitCodeProcess() and ntstatus.h for possible
 180          * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
 181          * References:
 182          *   https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
 183          *   https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
 184          */
 185 #ifdef G_OS_WIN32
 186         /* Additionally WIN32 does not provide any additional information
 187          * on whether the child exited or terminated via signal.
 188          * We use this simple range check to distinguish application exit code
 189          * (usually value less then 256) and unhandled exception code with
 190          * ntstatus (always value greater then 0xC0000005). */
 191         if ((uint32_t)gei->status < 0xC0000000U) {
 192             ges->has_exitcode = true;
 193             ges->exitcode = gei->status;
 194         } else {
 195             ges->has_signal = true;
 196             ges->signal = gei->status;
 197         }
 198 #else
 199         if (WIFEXITED(gei->status)) {
 200             ges->has_exitcode = true;
 201             ges->exitcode = WEXITSTATUS(gei->status);
 202         } else if (WIFSIGNALED(gei->status)) {
 203             ges->has_signal = true;
 204             ges->signal = WTERMSIG(gei->status);
 205         }
 206 #endif
 207         if (gei->out.length > 0) {
 208             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
 209             ges->has_out_truncated = gei->out.truncated;
 210         }
 211         g_free(gei->out.data);
 212
 213         if (gei->err.length > 0) {
 214             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
 215             ges->has_err_truncated = gei->err.truncated;
 216         }
 217         g_free(gei->err.data);
 218
 219         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
 220         g_free(gei);
 221     }
 222
 223     return ges;
 224 }
 225
 226 /* Get environment variables or arguments array for execve(). */
 227 static char **guest_exec_get_args(const strList *entry, bool log)
 228 {
 229     const strList *it;
 230     int count = 1, i = 0;  /* reserve for NULL terminator */
 231     char **args;
 232     char *str; /* for logging array of arguments */
 233     size_t str_size = 1;
 234
 235     for (it = entry; it != NULL; it = it->next) {
 236         count++;
 237         str_size += 1 + strlen(it->value);
 238     }
 239
 240     str = g_malloc(str_size);
 241     *str = 0;
 242     args = g_new(char *, count);
 243     for (it = entry; it != NULL; it = it->next) {
 244         args[i++] = it->value;
 245         pstrcat(str, str_size, it->value);
 246         if (it->next) {
 247             pstrcat(str, str_size, " ");
 248         }
 249     }
 250     args[i] = NULL;
 251
 252     if (log) {
 253         slog("guest-exec called: \"%s\"", str);
 254     }
 255     g_free(str);
 256
 257     return args;
 258 }
 259
 260 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
 261 {
 262     GuestExecInfo *gei = (GuestExecInfo *)data;
 263
 264     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
 265             (int32_t)gpid_to_int64(pid), (uint32_t)status);
 266
 267     gei->status = status;
 268     gei->finished = true;
 269
 270     g_spawn_close_pid(pid);
 271 }
 272
 273 static void guest_exec_task_setup(gpointer data)
 274 {
 275 #if !defined(G_OS_WIN32)
 276     bool has_merge = *(bool *)data;
 277     struct sigaction sigact;
 278
 279     if (has_merge) {
 280         /*
 281          * FIXME: When `GLIB_VERSION_MIN_REQUIRED` is bumped to 2.58+, use
 282          * g_spawn_async_with_fds() to be portable on windows. The current
 283          * logic does not work on windows b/c `GSpawnChildSetupFunc` is run
 284          * inside the parent, not the child.
 285          */
 286         if (dup2(STDOUT_FILENO, STDERR_FILENO) != 0) {
 287             slog("dup2() failed to merge stderr into stdout: %s",
 288                  strerror(errno));
 289         }
 290     }
 291
 292     /* Reset ignored signals back to default. */
 293     memset(&sigact, 0, sizeof(struct sigaction));
 294     sigact.sa_handler = SIG_DFL;
 295
 296     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 297         slog("sigaction() failed to reset child process's SIGPIPE: %s",
 298              strerror(errno));
 299     }
 300 #endif
 301 }
 302
 303 static gboolean guest_exec_input_watch(GIOChannel *ch,
 304         GIOCondition cond, gpointer p_)
 305 {
 306     GuestExecIOData *p = (GuestExecIOData *)p_;
 307     gsize bytes_written = 0;
 308     GIOStatus status;
 309     GError *gerr = NULL;
 310
 311     /* nothing left to write */
 312     if (p->size == p->length) {
 313         goto done;
 314     }
 315
 316     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
 317             p->size - p->length, &bytes_written, &gerr);
 318
 319     /* can be not 0 even if not G_IO_STATUS_NORMAL */
 320     if (bytes_written != 0) {
 321         p->length += bytes_written;
 322     }
 323
 324     /* continue write, our callback will be called again */
 325     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
 326         return true;
 327     }
 328
 329     if (gerr) {
 330         g_warning("qga: i/o error writing to input_data channel: %s",
 331                 gerr->message);
 332         g_error_free(gerr);
 333     }
 334
 335 done:
 336     g_io_channel_shutdown(ch, true, NULL);
 337     g_io_channel_unref(ch);
 338     p->closed = true;
 339     g_free(p->data);
 340
 341     return false;
 342 }
 343
 344 static gboolean guest_exec_output_watch(GIOChannel *ch,
 345         GIOCondition cond, gpointer p_)
 346 {
 347     GuestExecIOData *p = (GuestExecIOData *)p_;
 348     gsize bytes_read;
 349     GIOStatus gstatus;
 350
 351     if (cond == G_IO_HUP || cond == G_IO_ERR) {
 352         goto close;
 353     }
 354
 355     if (p->size == p->length) {
 356         gpointer t = NULL;
 357         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
 358             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
 359         }
 360         if (t == NULL) {
 361             /* ignore truncated output */
 362             gchar buf[GUEST_EXEC_IO_SIZE];
 363
 364             p->truncated = true;
 365             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
 366                                               &bytes_read, NULL);
 367             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 368                 goto close;
 369             }
 370
 371             return true;
 372         }
 373         p->size += GUEST_EXEC_IO_SIZE;
 374         p->data = t;
 375     }
 376
 377     /* Calling read API once.
 378      * On next available data our callback will be called again */
 379     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
 380             p->size - p->length, &bytes_read, NULL);
 381     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 382         goto close;
 383     }
 384
 385     p->length += bytes_read;
 386
 387     return true;
 388
 389 close:
 390     g_io_channel_shutdown(ch, true, NULL);
 391     g_io_channel_unref(ch);
 392     p->closed = true;
 393     return false;
 394 }
 395
 396 static GuestExecCaptureOutputMode ga_parse_capture_output(
 397         GuestExecCaptureOutput *capture_output)
 398 {
 399     if (!capture_output)
 400         return GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE;
 401     else if (capture_output->type == QTYPE_QBOOL)
 402         return capture_output->u.flag ? GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED
 403                                       : GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE;
 404     else
 405         return capture_output->u.mode;
 406 }
 407
 408 GuestExec *qmp_guest_exec(const char *path,
 409                        bool has_arg, strList *arg,
 410                        bool has_env, strList *env,
 411                        const char *input_data,
 412                        GuestExecCaptureOutput *capture_output,
 413                        Error **errp)
 414 {
 415     GPid pid;
 416     GuestExec *ge = NULL;
 417     GuestExecInfo *gei;
 418     char **argv, **envp;
 419     strList arglist;
 420     gboolean ret;
 421     GError *gerr = NULL;
 422     gint in_fd, out_fd, err_fd;
 423     GIOChannel *in_ch, *out_ch, *err_ch;
 424     GSpawnFlags flags;
 425     bool has_output = false;
 426     bool has_merge = false;
 427     GuestExecCaptureOutputMode output_mode;
 428     g_autofree uint8_t *input = NULL;
 429     size_t ninput = 0;
 430
 431     arglist.value = (char *)path;
 432     arglist.next = has_arg ? arg : NULL;
 433
 434     if (input_data) {
 435         input = qbase64_decode(input_data, -1, &ninput, errp);
 436         if (!input) {
 437             return NULL;
 438         }
 439     }
 440
 441     argv = guest_exec_get_args(&arglist, true);
 442     envp = has_env ? guest_exec_get_args(env, false) : NULL;
 443
 444     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD |
 445         G_SPAWN_SEARCH_PATH_FROM_ENVP;
 446
 447     output_mode = ga_parse_capture_output(capture_output);
 448     switch (output_mode) {
 449     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE:
 450         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
 451         break;
 452     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_STDOUT:
 453         has_output = true;
 454         flags |= G_SPAWN_STDERR_TO_DEV_NULL;
 455         break;
 456     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_STDERR:
 457         has_output = true;
 458         flags |= G_SPAWN_STDOUT_TO_DEV_NULL;
 459         break;
 460     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED:
 461         has_output = true;
 462         break;
 463 #if !defined(G_OS_WIN32)
 464     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_MERGED:
 465         has_output = true;
 466         has_merge = true;
 467         break;
 468 #endif
 469     case GUEST_EXEC_CAPTURE_OUTPUT_MODE__MAX:
 470         /* Silence warning; impossible branch */
 471         break;
 472     }
 473
 474     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
 475             guest_exec_task_setup, &has_merge, &pid, input_data ? &in_fd : NULL,
 476             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
 477     if (!ret) {
 478         error_setg(errp, QERR_QGA_COMMAND_FAILED, gerr->message);
 479         g_error_free(gerr);
 480         goto done;
 481     }
 482
 483     ge = g_new0(GuestExec, 1);
 484     ge->pid = gpid_to_int64(pid);
 485
 486     gei = guest_exec_info_add(pid);
 487     gei->has_output = has_output;
 488     g_child_watch_add(pid, guest_exec_child_watch, gei);
 489
 490     if (input_data) {
 491         gei->in.data = g_steal_pointer(&input);
 492         gei->in.size = ninput;
 493 #ifdef G_OS_WIN32
 494         in_ch = g_io_channel_win32_new_fd(in_fd);
 495 #else
 496         in_ch = g_io_channel_unix_new(in_fd);
 497 #endif
 498         g_io_channel_set_encoding(in_ch, NULL, NULL);
 499         g_io_channel_set_buffered(in_ch, false);
 500         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
 501         g_io_channel_set_close_on_unref(in_ch, true);
 502         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
 503     }
 504
 505     if (has_output) {
 506 #ifdef G_OS_WIN32
 507         out_ch = g_io_channel_win32_new_fd(out_fd);
 508         err_ch = g_io_channel_win32_new_fd(err_fd);
 509 #else
 510         out_ch = g_io_channel_unix_new(out_fd);
 511         err_ch = g_io_channel_unix_new(err_fd);
 512 #endif
 513         g_io_channel_set_encoding(out_ch, NULL, NULL);
 514         g_io_channel_set_encoding(err_ch, NULL, NULL);
 515         g_io_channel_set_buffered(out_ch, false);
 516         g_io_channel_set_buffered(err_ch, false);
 517         g_io_channel_set_close_on_unref(out_ch, true);
 518         g_io_channel_set_close_on_unref(err_ch, true);
 519         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
 520                 guest_exec_output_watch, &gei->out);
 521         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
 522                 guest_exec_output_watch, &gei->err);
 523     }
 524
 525 done:
 526     g_free(argv);
 527     g_free(envp);
 528
 529     return ge;
 530 }
 531
 532 /* Convert GuestFileWhence (either a raw integer or an enum value) into
 533  * the guest's SEEK_ constants.  */
 534 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
 535 {
 536     /*
 537      * Exploit the fact that we picked values to match QGA_SEEK_*;
 538      * however, we have to use a temporary variable since the union
 539      * members may have different size.
 540      */
 541     if (whence->type == QTYPE_QSTRING) {
 542         int value = whence->u.name;
 543         whence->type = QTYPE_QNUM;
 544         whence->u.value = value;
 545     }
 546     switch (whence->u.value) {
 547     case QGA_SEEK_SET:
 548         return SEEK_SET;
 549     case QGA_SEEK_CUR:
 550         return SEEK_CUR;
 551     case QGA_SEEK_END:
 552         return SEEK_END;
 553     }
 554     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
 555     return -1;
 556 }
 557
 558 GuestHostName *qmp_guest_get_host_name(Error **errp)
 559 {
 560     GuestHostName *result = NULL;
 561     g_autofree char *hostname = qga_get_host_name(errp);
 562
 563     /*
 564      * We want to avoid using g_get_host_name() because that
 565      * caches the result and we wouldn't reflect changes in the
 566      * host name.
 567      */
 568
 569     if (!hostname) {
 570         hostname = g_strdup("localhost");
 571     }
 572
 573     result = g_new0(GuestHostName, 1);
 574     result->host_name = g_steal_pointer(&hostname);
 575     return result;
 576 }
 577
 578 GuestTimezone *qmp_guest_get_timezone(Error **errp)
 579 {
 580     GuestTimezone *info = NULL;
 581     GTimeZone *tz = NULL;
 582     gint64 now = 0;
 583     gint32 intv = 0;
 584     gchar const *name = NULL;
 585
 586     info = g_new0(GuestTimezone, 1);
 587     tz = g_time_zone_new_local();
 588     if (tz == NULL) {
 589         error_setg(errp, QERR_QGA_COMMAND_FAILED,
 590                    "Couldn't retrieve local timezone");
 591         goto error;
 592     }
 593
 594     now = g_get_real_time() / G_USEC_PER_SEC;
 595     intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
 596     info->offset = g_time_zone_get_offset(tz, intv);
 597     name = g_time_zone_get_abbreviation(tz, intv);
 598     if (name != NULL) {
 599         info->zone = g_strdup(name);
 600     }
 601     g_time_zone_unref(tz);
 602
 603     return info;
 604
 605 error:
 606     g_free(info);
 607     return NULL;
 608 }
 609
 610 GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
 611                                    int64_t count, Error **errp)
 612 {
 613     GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
 614     GuestFileRead *read_data;
 615
 616     if (!gfh) {
 617         return NULL;
 618     }
 619     if (!has_count) {
 620         count = QGA_READ_COUNT_DEFAULT;
 621     } else if (count < 0 || count > GUEST_FILE_READ_COUNT_MAX) {
 622         error_setg(errp, "value '%" PRId64 "' is invalid for argument count",
 623                    count);
 624         return NULL;
 625     }
 626
 627     read_data = guest_file_read_unsafe(gfh, count, errp);
 628     if (!read_data) {
 629         slog("guest-file-write failed, handle: %" PRId64, handle);
 630     }
 631
 632     return read_data;
 633 }
 634
 635 int64_t qmp_guest_get_time(Error **errp)
 636 {
 637     return g_get_real_time() * 1000;
 638 }