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