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->out_data = g_base64_encode(gei->out.data, gei->out.length);
 210             g_free(gei->out.data);
 211             ges->has_out_truncated = gei->out.truncated;
 212         }
 213
 214         if (gei->err.length > 0) {
 215             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
 216             g_free(gei->err.data);
 217             ges->has_err_truncated = gei->err.truncated;
 218         }
 219
 220         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
 221         g_free(gei);
 222     }
 223
 224     return ges;
 225 }
 226
 227 /* Get environment variables or arguments array for execve(). */
 228 static char **guest_exec_get_args(const strList *entry, bool log)
 229 {
 230     const strList *it;
 231     int count = 1, i = 0;  /* reserve for NULL terminator */
 232     char **args;
 233     char *str; /* for logging array of arguments */
 234     size_t str_size = 1;
 235
 236     for (it = entry; it != NULL; it = it->next) {
 237         count++;
 238         str_size += 1 + strlen(it->value);
 239     }
 240
 241     str = g_malloc(str_size);
 242     *str = 0;
 243     args = g_new(char *, count);
 244     for (it = entry; it != NULL; it = it->next) {
 245         args[i++] = it->value;
 246         pstrcat(str, str_size, it->value);
 247         if (it->next) {
 248             pstrcat(str, str_size, " ");
 249         }
 250     }
 251     args[i] = NULL;
 252
 253     if (log) {
 254         slog("guest-exec called: \"%s\"", str);
 255     }
 256     g_free(str);
 257
 258     return args;
 259 }
 260
 261 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
 262 {
 263     GuestExecInfo *gei = (GuestExecInfo *)data;
 264
 265     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
 266             (int32_t)gpid_to_int64(pid), (uint32_t)status);
 267
 268     gei->status = status;
 269     gei->finished = true;
 270
 271     g_spawn_close_pid(pid);
 272 }
 273
 274 /** Reset ignored signals back to default. */
 275 static void guest_exec_task_setup(gpointer data)
 276 {
 277 #if !defined(G_OS_WIN32)
 278     struct sigaction sigact;
 279
 280     memset(&sigact, 0, sizeof(struct sigaction));
 281     sigact.sa_handler = SIG_DFL;
 282
 283     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 284         slog("sigaction() failed to reset child process's SIGPIPE: %s",
 285              strerror(errno));
 286     }
 287 #endif
 288 }
 289
 290 static gboolean guest_exec_input_watch(GIOChannel *ch,
 291         GIOCondition cond, gpointer p_)
 292 {
 293     GuestExecIOData *p = (GuestExecIOData *)p_;
 294     gsize bytes_written = 0;
 295     GIOStatus status;
 296     GError *gerr = NULL;
 297
 298     /* nothing left to write */
 299     if (p->size == p->length) {
 300         goto done;
 301     }
 302
 303     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
 304             p->size - p->length, &bytes_written, &gerr);
 305
 306     /* can be not 0 even if not G_IO_STATUS_NORMAL */
 307     if (bytes_written != 0) {
 308         p->length += bytes_written;
 309     }
 310
 311     /* continue write, our callback will be called again */
 312     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
 313         return true;
 314     }
 315
 316     if (gerr) {
 317         g_warning("qga: i/o error writing to input_data channel: %s",
 318                 gerr->message);
 319         g_error_free(gerr);
 320     }
 321
 322 done:
 323     g_io_channel_shutdown(ch, true, NULL);
 324     g_io_channel_unref(ch);
 325     p->closed = true;
 326     g_free(p->data);
 327
 328     return false;
 329 }
 330
 331 static gboolean guest_exec_output_watch(GIOChannel *ch,
 332         GIOCondition cond, gpointer p_)
 333 {
 334     GuestExecIOData *p = (GuestExecIOData *)p_;
 335     gsize bytes_read;
 336     GIOStatus gstatus;
 337
 338     if (cond == G_IO_HUP || cond == G_IO_ERR) {
 339         goto close;
 340     }
 341
 342     if (p->size == p->length) {
 343         gpointer t = NULL;
 344         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
 345             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
 346         }
 347         if (t == NULL) {
 348             /* ignore truncated output */
 349             gchar buf[GUEST_EXEC_IO_SIZE];
 350
 351             p->truncated = true;
 352             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
 353                                               &bytes_read, NULL);
 354             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 355                 goto close;
 356             }
 357
 358             return true;
 359         }
 360         p->size += GUEST_EXEC_IO_SIZE;
 361         p->data = t;
 362     }
 363
 364     /* Calling read API once.
 365      * On next available data our callback will be called again */
 366     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
 367             p->size - p->length, &bytes_read, NULL);
 368     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 369         goto close;
 370     }
 371
 372     p->length += bytes_read;
 373
 374     return true;
 375
 376 close:
 377     g_io_channel_shutdown(ch, true, NULL);
 378     g_io_channel_unref(ch);
 379     p->closed = true;
 380     return false;
 381 }
 382
 383 GuestExec *qmp_guest_exec(const char *path,
 384                        bool has_arg, strList *arg,
 385                        bool has_env, strList *env,
 386                        const char *input_data,
 387                        bool has_capture_output, bool capture_output,
 388                        Error **errp)
 389 {
 390     GPid pid;
 391     GuestExec *ge = NULL;
 392     GuestExecInfo *gei;
 393     char **argv, **envp;
 394     strList arglist;
 395     gboolean ret;
 396     GError *gerr = NULL;
 397     gint in_fd, out_fd, err_fd;
 398     GIOChannel *in_ch, *out_ch, *err_ch;
 399     GSpawnFlags flags;
 400     bool has_output = (has_capture_output && capture_output);
 401     g_autofree uint8_t *input = NULL;
 402     size_t ninput = 0;
 403
 404     arglist.value = (char *)path;
 405     arglist.next = has_arg ? arg : NULL;
 406
 407     if (input_data) {
 408         input = qbase64_decode(input_data, -1, &ninput, errp);
 409         if (!input) {
 410             return NULL;
 411         }
 412     }
 413
 414     argv = guest_exec_get_args(&arglist, true);
 415     envp = has_env ? guest_exec_get_args(env, false) : NULL;
 416
 417     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD |
 418         G_SPAWN_SEARCH_PATH_FROM_ENVP;
 419     if (!has_output) {
 420         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
 421     }
 422
 423     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
 424             guest_exec_task_setup, NULL, &pid, input_data ? &in_fd : NULL,
 425             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
 426     if (!ret) {
 427         error_setg(errp, QERR_QGA_COMMAND_FAILED, gerr->message);
 428         g_error_free(gerr);
 429         goto done;
 430     }
 431
 432     ge = g_new0(GuestExec, 1);
 433     ge->pid = gpid_to_int64(pid);
 434
 435     gei = guest_exec_info_add(pid);
 436     gei->has_output = has_output;
 437     g_child_watch_add(pid, guest_exec_child_watch, gei);
 438
 439     if (input_data) {
 440         gei->in.data = g_steal_pointer(&input);
 441         gei->in.size = ninput;
 442 #ifdef G_OS_WIN32
 443         in_ch = g_io_channel_win32_new_fd(in_fd);
 444 #else
 445         in_ch = g_io_channel_unix_new(in_fd);
 446 #endif
 447         g_io_channel_set_encoding(in_ch, NULL, NULL);
 448         g_io_channel_set_buffered(in_ch, false);
 449         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
 450         g_io_channel_set_close_on_unref(in_ch, true);
 451         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
 452     }
 453
 454     if (has_output) {
 455 #ifdef G_OS_WIN32
 456         out_ch = g_io_channel_win32_new_fd(out_fd);
 457         err_ch = g_io_channel_win32_new_fd(err_fd);
 458 #else
 459         out_ch = g_io_channel_unix_new(out_fd);
 460         err_ch = g_io_channel_unix_new(err_fd);
 461 #endif
 462         g_io_channel_set_encoding(out_ch, NULL, NULL);
 463         g_io_channel_set_encoding(err_ch, NULL, NULL);
 464         g_io_channel_set_buffered(out_ch, false);
 465         g_io_channel_set_buffered(err_ch, false);
 466         g_io_channel_set_close_on_unref(out_ch, true);
 467         g_io_channel_set_close_on_unref(err_ch, true);
 468         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
 469                 guest_exec_output_watch, &gei->out);
 470         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
 471                 guest_exec_output_watch, &gei->err);
 472     }
 473
 474 done:
 475     g_free(argv);
 476     g_free(envp);
 477
 478     return ge;
 479 }
 480
 481 /* Convert GuestFileWhence (either a raw integer or an enum value) into
 482  * the guest's SEEK_ constants.  */
 483 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
 484 {
 485     /*
 486      * Exploit the fact that we picked values to match QGA_SEEK_*;
 487      * however, we have to use a temporary variable since the union
 488      * members may have different size.
 489      */
 490     if (whence->type == QTYPE_QSTRING) {
 491         int value = whence->u.name;
 492         whence->type = QTYPE_QNUM;
 493         whence->u.value = value;
 494     }
 495     switch (whence->u.value) {
 496     case QGA_SEEK_SET:
 497         return SEEK_SET;
 498     case QGA_SEEK_CUR:
 499         return SEEK_CUR;
 500     case QGA_SEEK_END:
 501         return SEEK_END;
 502     }
 503     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
 504     return -1;
 505 }
 506
 507 GuestHostName *qmp_guest_get_host_name(Error **errp)
 508 {
 509     GuestHostName *result = NULL;
 510     g_autofree char *hostname = qga_get_host_name(errp);
 511
 512     /*
 513      * We want to avoid using g_get_host_name() because that
 514      * caches the result and we wouldn't reflect changes in the
 515      * host name.
 516      */
 517
 518     if (!hostname) {
 519         hostname = g_strdup("localhost");
 520     }
 521
 522     result = g_new0(GuestHostName, 1);
 523     result->host_name = g_steal_pointer(&hostname);
 524     return result;
 525 }
 526
 527 GuestTimezone *qmp_guest_get_timezone(Error **errp)
 528 {
 529     GuestTimezone *info = NULL;
 530     GTimeZone *tz = NULL;
 531     gint64 now = 0;
 532     gint32 intv = 0;
 533     gchar const *name = NULL;
 534
 535     info = g_new0(GuestTimezone, 1);
 536     tz = g_time_zone_new_local();
 537     if (tz == NULL) {
 538         error_setg(errp, QERR_QGA_COMMAND_FAILED,
 539                    "Couldn't retrieve local timezone");
 540         goto error;
 541     }
 542
 543     now = g_get_real_time() / G_USEC_PER_SEC;
 544     intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
 545     info->offset = g_time_zone_get_offset(tz, intv);
 546     name = g_time_zone_get_abbreviation(tz, intv);
 547     if (name != NULL) {
 548         info->zone = g_strdup(name);
 549     }
 550     g_time_zone_unref(tz);
 551
 552     return info;
 553
 554 error:
 555     g_free(info);
 556     return NULL;
 557 }
 558
 559 GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
 560                                    int64_t count, Error **errp)
 561 {
 562     GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
 563     GuestFileRead *read_data;
 564
 565     if (!gfh) {
 566         return NULL;
 567     }
 568     if (!has_count) {
 569         count = QGA_READ_COUNT_DEFAULT;
 570     } else if (count < 0 || count > GUEST_FILE_READ_COUNT_MAX) {
 571         error_setg(errp, "value '%" PRId64 "' is invalid for argument count",
 572                    count);
 573         return NULL;
 574     }
 575
 576     read_data = guest_file_read_unsafe(gfh, count, errp);
 577     if (!read_data) {
 578         slog("guest-file-write failed, handle: %" PRId64, handle);
 579     }
 580
 581     return read_data;
 582 }
 583
 584 int64_t qmp_guest_get_time(Error **errp)
 585 {
 586     return g_get_real_time() * 1000;
 587 }