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 "qga/guest-agent-core.h"
  15 #include "qga-qapi-commands.h"
  16 #include "qapi/error.h"
  17 #include "qapi/qmp/qerror.h"
  18 #include "qemu/base64.h"
  19 #include "qemu/cutils.h"
  20 #include "qemu/atomic.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 /* Note: in some situations, like with the fsfreeze, logging may be
  28  * temporarilly disabled. if it is necessary that a command be able
  29  * to log for accounting purposes, check ga_logging_enabled() beforehand,
  30  * and use the QERR_QGA_LOGGING_DISABLED to generate an error
  31  */
  32 void slog(const gchar *fmt, ...)
  33 {
  34     va_list ap;
  35
  36     va_start(ap, fmt);
  37     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
  38     va_end(ap);
  39 }
  40
  41 int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
  42 {
  43     ga_set_response_delimited(ga_state);
  44     return id;
  45 }
  46
  47 int64_t qmp_guest_sync(int64_t id, Error **errp)
  48 {
  49     return id;
  50 }
  51
  52 void qmp_guest_ping(Error **errp)
  53 {
  54     slog("guest-ping called");
  55 }
  56
  57 static void qmp_command_info(QmpCommand *cmd, void *opaque)
  58 {
  59     GuestAgentInfo *info = opaque;
  60     GuestAgentCommandInfo *cmd_info;
  61     GuestAgentCommandInfoList *cmd_info_list;
  62
  63     cmd_info = g_new0(GuestAgentCommandInfo, 1);
  64     cmd_info->name = g_strdup(qmp_command_name(cmd));
  65     cmd_info->enabled = qmp_command_is_enabled(cmd);
  66     cmd_info->success_response = qmp_has_success_response(cmd);
  67
  68     cmd_info_list = g_new0(GuestAgentCommandInfoList, 1);
  69     cmd_info_list->value = cmd_info;
  70     cmd_info_list->next = info->supported_commands;
  71     info->supported_commands = cmd_info_list;
  72 }
  73
  74 struct GuestAgentInfo *qmp_guest_info(Error **errp)
  75 {
  76     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
  77
  78     info->version = g_strdup(QEMU_VERSION);
  79     qmp_for_each_command(&ga_commands, qmp_command_info, info);
  80     return info;
  81 }
  82
  83 struct GuestExecIOData {
  84     guchar *data;
  85     gsize size;
  86     gsize length;
  87     bool closed;
  88     bool truncated;
  89     const char *name;
  90 };
  91 typedef struct GuestExecIOData GuestExecIOData;
  92
  93 struct GuestExecInfo {
  94     GPid pid;
  95     int64_t pid_numeric;
  96     gint status;
  97     bool has_output;
  98     bool finished;
  99     GuestExecIOData in;
 100     GuestExecIOData out;
 101     GuestExecIOData err;
 102     QTAILQ_ENTRY(GuestExecInfo) next;
 103 };
 104 typedef struct GuestExecInfo GuestExecInfo;
 105
 106 static struct {
 107     QTAILQ_HEAD(, GuestExecInfo) processes;
 108 } guest_exec_state = {
 109     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 110 };
 111
 112 static int64_t gpid_to_int64(GPid pid)
 113 {
 114 #ifdef G_OS_WIN32
 115     return GetProcessId(pid);
 116 #else
 117     return (int64_t)pid;
 118 #endif
 119 }
 120
 121 static GuestExecInfo *guest_exec_info_add(GPid pid)
 122 {
 123     GuestExecInfo *gei;
 124
 125     gei = g_new0(GuestExecInfo, 1);
 126     gei->pid = pid;
 127     gei->pid_numeric = gpid_to_int64(pid);
 128     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
 129
 130     return gei;
 131 }
 132
 133 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
 134 {
 135     GuestExecInfo *gei;
 136
 137     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
 138         if (gei->pid_numeric == pid_numeric) {
 139             return gei;
 140         }
 141     }
 142
 143     return NULL;
 144 }
 145
 146 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err)
 147 {
 148     GuestExecInfo *gei;
 149     GuestExecStatus *ges;
 150
 151     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
 152
 153     gei = guest_exec_info_find(pid);
 154     if (gei == NULL) {
 155         error_setg(err, QERR_INVALID_PARAMETER, "pid");
 156         return NULL;
 157     }
 158
 159     ges = g_new0(GuestExecStatus, 1);
 160
 161     bool finished = atomic_mb_read(&gei->finished);
 162
 163     /* need to wait till output channels are closed
 164      * to be sure we captured all output at this point */
 165     if (gei->has_output) {
 166         finished = finished && atomic_mb_read(&gei->out.closed);
 167         finished = finished && atomic_mb_read(&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->has_out_data = true;
 208             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
 209             g_free(gei->out.data);
 210             ges->has_out_truncated = gei->out.truncated;
 211         }
 212
 213         if (gei->err.length > 0) {
 214             ges->has_err_data = true;
 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_malloc(count * sizeof(char *));
 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     atomic_mb_set(&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     atomic_mb_set(&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     atomic_mb_set(&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                        bool has_input_data, const char *input_data,
 387                        bool has_capture_output, bool capture_output,
 388                        Error **err)
 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     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 (has_input_data) {
 408         input = qbase64_decode(input_data, -1, &ninput, err);
 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 #if GLIB_CHECK_VERSION(2, 33, 2)
 419     flags |= G_SPAWN_SEARCH_PATH_FROM_ENVP;
 420 #endif
 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(err, 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 = 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     /* Exploit the fact that we picked values to match QGA_SEEK_*. */
 488     if (whence->type == QTYPE_QSTRING) {
 489         whence->type = QTYPE_QNUM;
 490         whence->u.value = whence->u.name;
 491     }
 492     switch (whence->u.value) {
 493     case QGA_SEEK_SET:
 494         return SEEK_SET;
 495     case QGA_SEEK_CUR:
 496         return SEEK_CUR;
 497     case QGA_SEEK_END:
 498         return SEEK_END;
 499     }
 500     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
 501     return -1;
 502 }
 503
 504 GuestHostName *qmp_guest_get_host_name(Error **err)
 505 {
 506     GuestHostName *result = NULL;
 507     gchar const *hostname = g_get_host_name();
 508     if (hostname != NULL) {
 509         result = g_new0(GuestHostName, 1);
 510         result->host_name = g_strdup(hostname);
 511     }
 512     return result;
 513 }
 514
 515 GuestTimezone *qmp_guest_get_timezone(Error **errp)
 516 {
 517 #if GLIB_CHECK_VERSION(2, 28, 0)
 518     GuestTimezone *info = NULL;
 519     GTimeZone *tz = NULL;
 520     gint64 now = 0;
 521     gint32 intv = 0;
 522     gchar const *name = NULL;
 523
 524     info = g_new0(GuestTimezone, 1);
 525     tz = g_time_zone_new_local();
 526     if (tz == NULL) {
 527         error_setg(errp, QERR_QGA_COMMAND_FAILED,
 528                    "Couldn't retrieve local timezone");
 529         goto error;
 530     }
 531
 532     now = g_get_real_time() / G_USEC_PER_SEC;
 533     intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
 534     info->offset = g_time_zone_get_offset(tz, intv);
 535     name = g_time_zone_get_abbreviation(tz, intv);
 536     if (name != NULL) {
 537         info->has_zone = true;
 538         info->zone = g_strdup(name);
 539     }
 540     g_time_zone_unref(tz);
 541
 542     return info;
 543
 544 error:
 545     g_free(info);
 546     return NULL;
 547 #else
 548     error_setg(errp, QERR_UNSUPPORTED);
 549     return NULL;
 550 #endif
 551 }