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 "qemu/base64.h"
  19 #include "qemu/cutils.h"
  20 #include "commands-common.h"
  21
  22 /* Maximum captured guest-exec out_data/err_data - 16MB */
  23 #define GUEST_EXEC_MAX_OUTPUT (16 * 1024 * 1024)
  24 /* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
  25 #define GUEST_EXEC_IO_SIZE (4 * 1024)
  26 /*
  27  * Maximum file size to read - 48MB
  28  *
  29  * (48MB + Base64 3:4 overhead = JSON parser 64 MB limit)
  30  */
  31 #define GUEST_FILE_READ_COUNT_MAX (48 * MiB)
  32
  33 /* Note: in some situations, like with the fsfreeze, logging may be
  34  * temporarily disabled. if it is necessary that a command be able
  35  * to log for accounting purposes, check ga_logging_enabled() beforehand.
  36  */
  37 void slog(const gchar *fmt, ...)
  38 {
  39     va_list ap;
  40
  41     va_start(ap, fmt);
  42     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
  43     va_end(ap);
  44 }
  45
  46 int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
  47 {
  48     ga_set_response_delimited(ga_state);
  49     return id;
  50 }
  51
  52 int64_t qmp_guest_sync(int64_t id, Error **errp)
  53 {
  54     return id;
  55 }
  56
  57 void qmp_guest_ping(Error **errp)
  58 {
  59     slog("guest-ping called");
  60 }
  61
  62 static void qmp_command_info(const QmpCommand *cmd, void *opaque)
  63 {
  64     GuestAgentInfo *info = opaque;
  65     GuestAgentCommandInfo *cmd_info;
  66
  67     cmd_info = g_new0(GuestAgentCommandInfo, 1);
  68     cmd_info->name = g_strdup(qmp_command_name(cmd));
  69     cmd_info->enabled = qmp_command_is_enabled(cmd);
  70     cmd_info->success_response = qmp_has_success_response(cmd);
  71
  72     QAPI_LIST_PREPEND(info->supported_commands, cmd_info);
  73 }
  74
  75 struct GuestAgentInfo *qmp_guest_info(Error **errp)
  76 {
  77     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
  78
  79     info->version = g_strdup(QEMU_VERSION);
  80     qmp_for_each_command(&ga_commands, qmp_command_info, info);
  81     return info;
  82 }
  83
  84 struct GuestExecIOData {
  85     guchar *data;
  86     gsize size;
  87     gsize length;
  88     bool closed;
  89     bool truncated;
  90     const char *name;
  91 };
  92 typedef struct GuestExecIOData GuestExecIOData;
  93
  94 struct GuestExecInfo {
  95     GPid pid;
  96     int64_t pid_numeric;
  97     gint status;
  98     bool has_output;
  99     bool finished;
 100     GuestExecIOData in;
 101     GuestExecIOData out;
 102     GuestExecIOData err;
 103     QTAILQ_ENTRY(GuestExecInfo) next;
 104 };
 105 typedef struct GuestExecInfo GuestExecInfo;
 106
 107 static struct {
 108     QTAILQ_HEAD(, GuestExecInfo) processes;
 109 } guest_exec_state = {
 110     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 111 };
 112
 113 static int64_t gpid_to_int64(GPid pid)
 114 {
 115 #ifdef G_OS_WIN32
 116     return GetProcessId(pid);
 117 #else
 118     return (int64_t)pid;
 119 #endif
 120 }
 121
 122 static GuestExecInfo *guest_exec_info_add(GPid pid)
 123 {
 124     GuestExecInfo *gei;
 125
 126     gei = g_new0(GuestExecInfo, 1);
 127     gei->pid = pid;
 128     gei->pid_numeric = gpid_to_int64(pid);
 129     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
 130
 131     return gei;
 132 }
 133
 134 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
 135 {
 136     GuestExecInfo *gei;
 137
 138     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
 139         if (gei->pid_numeric == pid_numeric) {
 140             return gei;
 141         }
 142     }
 143
 144     return NULL;
 145 }
 146
 147 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **errp)
 148 {
 149     GuestExecInfo *gei;
 150     GuestExecStatus *ges;
 151
 152     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
 153
 154     gei = guest_exec_info_find(pid);
 155     if (gei == NULL) {
 156         error_setg(errp, "PID " PRId64 " does not exist");
 157         return NULL;
 158     }
 159
 160     ges = g_new0(GuestExecStatus, 1);
 161
 162     bool finished = gei->finished;
 163
 164     /* need to wait till output channels are closed
 165      * to be sure we captured all output at this point */
 166     if (gei->has_output) {
 167         finished &= gei->out.closed && gei->err.closed;
 168     }
 169
 170     ges->exited = finished;
 171     if (finished) {
 172         /* Glib has no portable way to parse exit status.
 173          * On UNIX, we can get either exit code from normal termination
 174          * or signal number.
 175          * On Windows, it is either the same exit code or the exception
 176          * value for an unhandled exception that caused the process
 177          * to terminate.
 178          * See MSDN for GetExitCodeProcess() and ntstatus.h for possible
 179          * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
 180          * References:
 181          *   https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
 182          *   https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
 183          */
 184 #ifdef G_OS_WIN32
 185         /* Additionally WIN32 does not provide any additional information
 186          * on whether the child exited or terminated via signal.
 187          * We use this simple range check to distinguish application exit code
 188          * (usually value less then 256) and unhandled exception code with
 189          * ntstatus (always value greater then 0xC0000005). */
 190         if ((uint32_t)gei->status < 0xC0000000U) {
 191             ges->has_exitcode = true;
 192             ges->exitcode = gei->status;
 193         } else {
 194             ges->has_signal = true;
 195             ges->signal = gei->status;
 196         }
 197 #else
 198         if (WIFEXITED(gei->status)) {
 199             ges->has_exitcode = true;
 200             ges->exitcode = WEXITSTATUS(gei->status);
 201         } else if (WIFSIGNALED(gei->status)) {
 202             ges->has_signal = true;
 203             ges->signal = WTERMSIG(gei->status);
 204         }
 205 #endif
 206         if (gei->out.length > 0) {
 207             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
 208             ges->has_out_truncated = gei->out.truncated;
 209         }
 210         g_free(gei->out.data);
 211
 212         if (gei->err.length > 0) {
 213             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
 214             ges->has_err_truncated = gei->err.truncated;
 215         }
 216         g_free(gei->err.data);
 217
 218         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
 219         g_free(gei);
 220     }
 221
 222     return ges;
 223 }
 224
 225 /* Get environment variables or arguments array for execve(). */
 226 static char **guest_exec_get_args(const strList *entry, bool log)
 227 {
 228     const strList *it;
 229     int count = 1, i = 0;  /* reserve for NULL terminator */
 230     char **args;
 231     char *str; /* for logging array of arguments */
 232     size_t str_size = 1;
 233
 234     for (it = entry; it != NULL; it = it->next) {
 235         count++;
 236         str_size += 1 + strlen(it->value);
 237     }
 238
 239     str = g_malloc(str_size);
 240     *str = 0;
 241     args = g_new(char *, count);
 242     for (it = entry; it != NULL; it = it->next) {
 243         args[i++] = it->value;
 244         pstrcat(str, str_size, it->value);
 245         if (it->next) {
 246             pstrcat(str, str_size, " ");
 247         }
 248     }
 249     args[i] = NULL;
 250
 251     if (log) {
 252         slog("guest-exec called: \"%s\"", str);
 253     }
 254     g_free(str);
 255
 256     return args;
 257 }
 258
 259 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
 260 {
 261     GuestExecInfo *gei = (GuestExecInfo *)data;
 262
 263     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
 264             (int32_t)gpid_to_int64(pid), (uint32_t)status);
 265
 266     gei->status = status;
 267     gei->finished = true;
 268
 269     g_spawn_close_pid(pid);
 270 }
 271
 272 static void guest_exec_task_setup(gpointer data)
 273 {
 274 #if !defined(G_OS_WIN32)
 275     bool has_merge = *(bool *)data;
 276     struct sigaction sigact;
 277
 278     if (has_merge) {
 279         /*
 280          * FIXME: When `GLIB_VERSION_MIN_REQUIRED` is bumped to 2.58+, use
 281          * g_spawn_async_with_fds() to be portable on windows. The current
 282          * logic does not work on windows b/c `GSpawnChildSetupFunc` is run
 283          * inside the parent, not the child.
 284          */
 285         if (dup2(STDOUT_FILENO, STDERR_FILENO) != 0) {
 286             slog("dup2() failed to merge stderr into stdout: %s",
 287                  strerror(errno));
 288         }
 289     }
 290
 291     /* Reset ignored signals back to default. */
 292     memset(&sigact, 0, sizeof(struct sigaction));
 293     sigact.sa_handler = SIG_DFL;
 294
 295     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 296         slog("sigaction() failed to reset child process's SIGPIPE: %s",
 297              strerror(errno));
 298     }
 299 #endif
 300 }
 301
 302 static gboolean guest_exec_input_watch(GIOChannel *ch,
 303         GIOCondition cond, gpointer p_)
 304 {
 305     GuestExecIOData *p = (GuestExecIOData *)p_;
 306     gsize bytes_written = 0;
 307     GIOStatus status;
 308     GError *gerr = NULL;
 309
 310     /* nothing left to write */
 311     if (p->size == p->length) {
 312         goto done;
 313     }
 314
 315     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
 316             p->size - p->length, &bytes_written, &gerr);
 317
 318     /* can be not 0 even if not G_IO_STATUS_NORMAL */
 319     if (bytes_written != 0) {
 320         p->length += bytes_written;
 321     }
 322
 323     /* continue write, our callback will be called again */
 324     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
 325         return true;
 326     }
 327
 328     if (gerr) {
 329         g_warning("qga: i/o error writing to input_data channel: %s",
 330                 gerr->message);
 331         g_error_free(gerr);
 332     }
 333
 334 done:
 335     g_io_channel_shutdown(ch, true, NULL);
 336     g_io_channel_unref(ch);
 337     p->closed = true;
 338     g_free(p->data);
 339
 340     return false;
 341 }
 342
 343 static gboolean guest_exec_output_watch(GIOChannel *ch,
 344         GIOCondition cond, gpointer p_)
 345 {
 346     GuestExecIOData *p = (GuestExecIOData *)p_;
 347     gsize bytes_read;
 348     GIOStatus gstatus;
 349
 350     if (cond == G_IO_HUP || cond == G_IO_ERR) {
 351         goto close;
 352     }
 353
 354     if (p->size == p->length) {
 355         gpointer t = NULL;
 356         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
 357             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
 358         }
 359         if (t == NULL) {
 360             /* ignore truncated output */
 361             gchar buf[GUEST_EXEC_IO_SIZE];
 362
 363             p->truncated = true;
 364             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
 365                                               &bytes_read, NULL);
 366             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 367                 goto close;
 368             }
 369
 370             return true;
 371         }
 372         p->size += GUEST_EXEC_IO_SIZE;
 373         p->data = t;
 374     }
 375
 376     /* Calling read API once.
 377      * On next available data our callback will be called again */
 378     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
 379             p->size - p->length, &bytes_read, NULL);
 380     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 381         goto close;
 382     }
 383
 384     p->length += bytes_read;
 385
 386     return true;
 387
 388 close:
 389     g_io_channel_shutdown(ch, true, NULL);
 390     g_io_channel_unref(ch);
 391     p->closed = true;
 392     return false;
 393 }
 394
 395 static GuestExecCaptureOutputMode ga_parse_capture_output(
 396         GuestExecCaptureOutput *capture_output)
 397 {
 398     if (!capture_output)
 399         return GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE;
 400     else if (capture_output->type == QTYPE_QBOOL)
 401         return capture_output->u.flag ? GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED
 402                                       : GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE;
 403     else
 404         return capture_output->u.mode;
 405 }
 406
 407 GuestExec *qmp_guest_exec(const char *path,
 408                        bool has_arg, strList *arg,
 409                        bool has_env, strList *env,
 410                        const char *input_data,
 411                        GuestExecCaptureOutput *capture_output,
 412                        Error **errp)
 413 {
 414     GPid pid;
 415     GuestExec *ge = NULL;
 416     GuestExecInfo *gei;
 417     char **argv, **envp;
 418     strList arglist;
 419     gboolean ret;
 420     GError *gerr = NULL;
 421     gint in_fd, out_fd, err_fd;
 422     GIOChannel *in_ch, *out_ch, *err_ch;
 423     GSpawnFlags flags;
 424     bool has_output = false;
 425     bool has_merge = false;
 426     GuestExecCaptureOutputMode output_mode;
 427     g_autofree uint8_t *input = NULL;
 428     size_t ninput = 0;
 429
 430     arglist.value = (char *)path;
 431     arglist.next = has_arg ? arg : NULL;
 432
 433     if (input_data) {
 434         input = qbase64_decode(input_data, -1, &ninput, errp);
 435         if (!input) {
 436             return NULL;
 437         }
 438     }
 439
 440     argv = guest_exec_get_args(&arglist, true);
 441     envp = has_env ? guest_exec_get_args(env, false) : NULL;
 442
 443     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD |
 444         G_SPAWN_SEARCH_PATH_FROM_ENVP;
 445
 446     output_mode = ga_parse_capture_output(capture_output);
 447     switch (output_mode) {
 448     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE:
 449         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
 450         break;
 451     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_STDOUT:
 452         has_output = true;
 453         flags |= G_SPAWN_STDERR_TO_DEV_NULL;
 454         break;
 455     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_STDERR:
 456         has_output = true;
 457         flags |= G_SPAWN_STDOUT_TO_DEV_NULL;
 458         break;
 459     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED:
 460         has_output = true;
 461         break;
 462 #if !defined(G_OS_WIN32)
 463     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_MERGED:
 464         has_output = true;
 465         has_merge = true;
 466         break;
 467 #endif
 468     case GUEST_EXEC_CAPTURE_OUTPUT_MODE__MAX:
 469         /* Silence warning; impossible branch */
 470         break;
 471     }
 472
 473     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
 474             guest_exec_task_setup, &has_merge, &pid, input_data ? &in_fd : NULL,
 475             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
 476     if (!ret) {
 477         error_setg(errp, "%s", gerr->message);
 478         g_error_free(gerr);
 479         goto done;
 480     }
 481
 482     ge = g_new0(GuestExec, 1);
 483     ge->pid = gpid_to_int64(pid);
 484
 485     gei = guest_exec_info_add(pid);
 486     gei->has_output = has_output;
 487     g_child_watch_add(pid, guest_exec_child_watch, gei);
 488
 489     if (input_data) {
 490         gei->in.data = g_steal_pointer(&input);
 491         gei->in.size = ninput;
 492 #ifdef G_OS_WIN32
 493         in_ch = g_io_channel_win32_new_fd(in_fd);
 494 #else
 495         in_ch = g_io_channel_unix_new(in_fd);
 496 #endif
 497         g_io_channel_set_encoding(in_ch, NULL, NULL);
 498         g_io_channel_set_buffered(in_ch, false);
 499         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
 500         g_io_channel_set_close_on_unref(in_ch, true);
 501         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
 502     }
 503
 504     if (has_output) {
 505 #ifdef G_OS_WIN32
 506         out_ch = g_io_channel_win32_new_fd(out_fd);
 507         err_ch = g_io_channel_win32_new_fd(err_fd);
 508 #else
 509         out_ch = g_io_channel_unix_new(out_fd);
 510         err_ch = g_io_channel_unix_new(err_fd);
 511 #endif
 512         g_io_channel_set_encoding(out_ch, NULL, NULL);
 513         g_io_channel_set_encoding(err_ch, NULL, NULL);
 514         g_io_channel_set_buffered(out_ch, false);
 515         g_io_channel_set_buffered(err_ch, false);
 516         g_io_channel_set_close_on_unref(out_ch, true);
 517         g_io_channel_set_close_on_unref(err_ch, true);
 518         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
 519                 guest_exec_output_watch, &gei->out);
 520         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
 521                 guest_exec_output_watch, &gei->err);
 522     }
 523
 524 done:
 525     g_free(argv);
 526     g_free(envp);
 527
 528     return ge;
 529 }
 530
 531 /* Convert GuestFileWhence (either a raw integer or an enum value) into
 532  * the guest's SEEK_ constants.  */
 533 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
 534 {
 535     /*
 536      * Exploit the fact that we picked values to match QGA_SEEK_*;
 537      * however, we have to use a temporary variable since the union
 538      * members may have different size.
 539      */
 540     if (whence->type == QTYPE_QSTRING) {
 541         int value = whence->u.name;
 542         whence->type = QTYPE_QNUM;
 543         whence->u.value = value;
 544     }
 545     switch (whence->u.value) {
 546     case QGA_SEEK_SET:
 547         return SEEK_SET;
 548     case QGA_SEEK_CUR:
 549         return SEEK_CUR;
 550     case QGA_SEEK_END:
 551         return SEEK_END;
 552     }
 553     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
 554     return -1;
 555 }
 556
 557 GuestHostName *qmp_guest_get_host_name(Error **errp)
 558 {
 559     GuestHostName *result = NULL;
 560     g_autofree char *hostname = qga_get_host_name(errp);
 561
 562     /*
 563      * We want to avoid using g_get_host_name() because that
 564      * caches the result and we wouldn't reflect changes in the
 565      * host name.
 566      */
 567
 568     if (!hostname) {
 569         hostname = g_strdup("localhost");
 570     }
 571
 572     result = g_new0(GuestHostName, 1);
 573     result->host_name = g_steal_pointer(&hostname);
 574     return result;
 575 }
 576
 577 GuestTimezone *qmp_guest_get_timezone(Error **errp)
 578 {
 579     GuestTimezone *info = NULL;
 580     GTimeZone *tz = NULL;
 581     gint64 now = 0;
 582     gint32 intv = 0;
 583     gchar const *name = NULL;
 584
 585     info = g_new0(GuestTimezone, 1);
 586     tz = g_time_zone_new_local();
 587     if (tz == NULL) {
 588         error_setg(errp, "Couldn't retrieve local timezone");
 589         goto error;
 590     }
 591
 592     now = g_get_real_time() / G_USEC_PER_SEC;
 593     intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
 594     info->offset = g_time_zone_get_offset(tz, intv);
 595     name = g_time_zone_get_abbreviation(tz, intv);
 596     if (name != NULL) {
 597         info->zone = g_strdup(name);
 598     }
 599     g_time_zone_unref(tz);
 600
 601     return info;
 602
 603 error:
 604     g_free(info);
 605     return NULL;
 606 }
 607
 608 GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
 609                                    int64_t count, Error **errp)
 610 {
 611     GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
 612     GuestFileRead *read_data;
 613
 614     if (!gfh) {
 615         return NULL;
 616     }
 617     if (!has_count) {
 618         count = QGA_READ_COUNT_DEFAULT;
 619     } else if (count < 0 || count > GUEST_FILE_READ_COUNT_MAX) {
 620         error_setg(errp, "value '%" PRId64 "' is invalid for argument count",
 621                    count);
 622         return NULL;
 623     }
 624
 625     read_data = guest_file_read_unsafe(gfh, count, errp);
 626     if (!read_data) {
 627         slog("guest-file-write failed, handle: %" PRId64, handle);
 628     }
 629
 630     return read_data;
 631 }
 632
 633 int64_t qmp_guest_get_time(Error **errp)
 634 {
 635     return g_get_real_time() * 1000;
 636 }