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