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-qmp-commands.h"
  16 #include "qapi/qmp/qerror.h"
  17 #include "qemu/base64.h"
  18 #include "qemu/cutils.h"
  19 #include "qemu/atomic.h"
  20
  21 /* Maximum captured guest-exec out_data/err_data - 16MB */
  22 #define GUEST_EXEC_MAX_OUTPUT (16*1024*1024)
  23 /* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
  24 #define GUEST_EXEC_IO_SIZE (4*1024)
  25
  26 /* Note: in some situations, like with the fsfreeze, logging may be
  27  * temporarilly disabled. if it is necessary that a command be able
  28  * to log for accounting purposes, check ga_logging_enabled() beforehand,
  29  * and use the QERR_QGA_LOGGING_DISABLED to generate an error
  30  */
  31 void slog(const gchar *fmt, ...)
  32 {
  33     va_list ap;
  34
  35     va_start(ap, fmt);
  36     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
  37     va_end(ap);
  38 }
  39
  40 int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
  41 {
  42     ga_set_response_delimited(ga_state);
  43     return id;
  44 }
  45
  46 int64_t qmp_guest_sync(int64_t id, Error **errp)
  47 {
  48     return id;
  49 }
  50
  51 void qmp_guest_ping(Error **errp)
  52 {
  53     slog("guest-ping called");
  54 }
  55
  56 static void qmp_command_info(QmpCommand *cmd, void *opaque)
  57 {
  58     GuestAgentInfo *info = opaque;
  59     GuestAgentCommandInfo *cmd_info;
  60     GuestAgentCommandInfoList *cmd_info_list;
  61
  62     cmd_info = g_new0(GuestAgentCommandInfo, 1);
  63     cmd_info->name = g_strdup(qmp_command_name(cmd));
  64     cmd_info->enabled = qmp_command_is_enabled(cmd);
  65     cmd_info->success_response = qmp_has_success_response(cmd);
  66
  67     cmd_info_list = g_new0(GuestAgentCommandInfoList, 1);
  68     cmd_info_list->value = cmd_info;
  69     cmd_info_list->next = info->supported_commands;
  70     info->supported_commands = cmd_info_list;
  71 }
  72
  73 struct GuestAgentInfo *qmp_guest_info(Error **errp)
  74 {
  75     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
  76
  77     info->version = g_strdup(QEMU_VERSION);
  78     qmp_for_each_command(qmp_command_info, info);
  79     return info;
  80 }
  81
  82 struct GuestExecIOData {
  83     guchar *data;
  84     gsize size;
  85     gsize length;
  86     bool closed;
  87     bool truncated;
  88     const char *name;
  89 };
  90 typedef struct GuestExecIOData GuestExecIOData;
  91
  92 struct GuestExecInfo {
  93     GPid pid;
  94     int64_t pid_numeric;
  95     gint status;
  96     bool has_output;
  97     bool finished;
  98     GuestExecIOData in;
  99     GuestExecIOData out;
 100     GuestExecIOData err;
 101     QTAILQ_ENTRY(GuestExecInfo) next;
 102 };
 103 typedef struct GuestExecInfo GuestExecInfo;
 104
 105 static struct {
 106     QTAILQ_HEAD(, GuestExecInfo) processes;
 107 } guest_exec_state = {
 108     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 109 };
 110
 111 static int64_t gpid_to_int64(GPid pid)
 112 {
 113 #ifdef G_OS_WIN32
 114     return GetProcessId(pid);
 115 #else
 116     return (int64_t)pid;
 117 #endif
 118 }
 119
 120 static GuestExecInfo *guest_exec_info_add(GPid pid)
 121 {
 122     GuestExecInfo *gei;
 123
 124     gei = g_new0(GuestExecInfo, 1);
 125     gei->pid = pid;
 126     gei->pid_numeric = gpid_to_int64(pid);
 127     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
 128
 129     return gei;
 130 }
 131
 132 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
 133 {
 134     GuestExecInfo *gei;
 135
 136     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
 137         if (gei->pid_numeric == pid_numeric) {
 138             return gei;
 139         }
 140     }
 141
 142     return NULL;
 143 }
 144
 145 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err)
 146 {
 147     GuestExecInfo *gei;
 148     GuestExecStatus *ges;
 149
 150     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
 151
 152     gei = guest_exec_info_find(pid);
 153     if (gei == NULL) {
 154         error_setg(err, QERR_INVALID_PARAMETER, "pid");
 155         return NULL;
 156     }
 157
 158     ges = g_new0(GuestExecStatus, 1);
 159
 160     bool finished = atomic_mb_read(&gei->finished);
 161
 162     /* need to wait till output channels are closed
 163      * to be sure we captured all output at this point */
 164     if (gei->has_output) {
 165         finished = finished && atomic_mb_read(&gei->out.closed);
 166         finished = finished && atomic_mb_read(&gei->err.closed);
 167     }
 168
 169     ges->exited = finished;
 170     if (finished) {
 171         /* Glib has no portable way to parse exit status.
 172          * On UNIX, we can get either exit code from normal termination
 173          * or signal number.
 174          * On Windows, it is either the same exit code or the exception
 175          * value for an unhandled exception that caused the process
 176          * to terminate.
 177          * See MSDN for GetExitCodeProcess() and ntstatus.h for possible
 178          * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
 179          * References:
 180          *   https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
 181          *   https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
 182          */
 183 #ifdef G_OS_WIN32
 184         /* Additionally WIN32 does not provide any additional information
 185          * on whether the child exited or terminated via signal.
 186          * We use this simple range check to distinguish application exit code
 187          * (usually value less then 256) and unhandled exception code with
 188          * ntstatus (always value greater then 0xC0000005). */
 189         if ((uint32_t)gei->status < 0xC0000000U) {
 190             ges->has_exitcode = true;
 191             ges->exitcode = gei->status;
 192         } else {
 193             ges->has_signal = true;
 194             ges->signal = gei->status;
 195         }
 196 #else
 197         if (WIFEXITED(gei->status)) {
 198             ges->has_exitcode = true;
 199             ges->exitcode = WEXITSTATUS(gei->status);
 200         } else if (WIFSIGNALED(gei->status)) {
 201             ges->has_signal = true;
 202             ges->signal = WTERMSIG(gei->status);
 203         }
 204 #endif
 205         if (gei->out.length > 0) {
 206             ges->has_out_data = true;
 207             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
 208             g_free(gei->out.data);
 209             ges->has_out_truncated = gei->out.truncated;
 210         }
 211
 212         if (gei->err.length > 0) {
 213             ges->has_err_data = true;
 214             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
 215             g_free(gei->err.data);
 216             ges->has_err_truncated = gei->err.truncated;
 217         }
 218
 219         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
 220         g_free(gei);
 221     }
 222
 223     return ges;
 224 }
 225
 226 /* Get environment variables or arguments array for execve(). */
 227 static char **guest_exec_get_args(const strList *entry, bool log)
 228 {
 229     const strList *it;
 230     int count = 1, i = 0;  /* reserve for NULL terminator */
 231     char **args;
 232     char *str; /* for logging array of arguments */
 233     size_t str_size = 1;
 234
 235     for (it = entry; it != NULL; it = it->next) {
 236         count++;
 237         str_size += 1 + strlen(it->value);
 238     }
 239
 240     str = g_malloc(str_size);
 241     *str = 0;
 242     args = g_malloc(count * sizeof(char *));
 243     for (it = entry; it != NULL; it = it->next) {
 244         args[i++] = it->value;
 245         pstrcat(str, str_size, it->value);
 246         if (it->next) {
 247             pstrcat(str, str_size, " ");
 248         }
 249     }
 250     args[i] = NULL;
 251
 252     if (log) {
 253         slog("guest-exec called: \"%s\"", str);
 254     }
 255     g_free(str);
 256
 257     return args;
 258 }
 259
 260 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
 261 {
 262     GuestExecInfo *gei = (GuestExecInfo *)data;
 263
 264     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
 265             (int32_t)gpid_to_int64(pid), (uint32_t)status);
 266
 267     gei->status = status;
 268     atomic_mb_set(&gei->finished, true);
 269
 270     g_spawn_close_pid(pid);
 271 }
 272
 273 /** Reset ignored signals back to default. */
 274 static void guest_exec_task_setup(gpointer data)
 275 {
 276 #if !defined(G_OS_WIN32)
 277     struct sigaction sigact;
 278
 279     memset(&sigact, 0, sizeof(struct sigaction));
 280     sigact.sa_handler = SIG_DFL;
 281
 282     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 283         slog("sigaction() failed to reset child process's SIGPIPE: %s",
 284              strerror(errno));
 285     }
 286 #endif
 287 }
 288
 289 static gboolean guest_exec_input_watch(GIOChannel *ch,
 290         GIOCondition cond, gpointer p_)
 291 {
 292     GuestExecIOData *p = (GuestExecIOData *)p_;
 293     gsize bytes_written = 0;
 294     GIOStatus status;
 295     GError *gerr = NULL;
 296
 297     /* nothing left to write */
 298     if (p->size == p->length) {
 299         goto done;
 300     }
 301
 302     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
 303             p->size - p->length, &bytes_written, &gerr);
 304
 305     /* can be not 0 even if not G_IO_STATUS_NORMAL */
 306     if (bytes_written != 0) {
 307         p->length += bytes_written;
 308     }
 309
 310     /* continue write, our callback will be called again */
 311     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
 312         return true;
 313     }
 314
 315     if (gerr) {
 316         g_warning("qga: i/o error writing to input_data channel: %s",
 317                 gerr->message);
 318         g_error_free(gerr);
 319     }
 320
 321 done:
 322     g_io_channel_shutdown(ch, true, NULL);
 323     g_io_channel_unref(ch);
 324     atomic_mb_set(&p->closed, true);
 325     g_free(p->data);
 326
 327     return false;
 328 }
 329
 330 static gboolean guest_exec_output_watch(GIOChannel *ch,
 331         GIOCondition cond, gpointer p_)
 332 {
 333     GuestExecIOData *p = (GuestExecIOData *)p_;
 334     gsize bytes_read;
 335     GIOStatus gstatus;
 336
 337     if (cond == G_IO_HUP || cond == G_IO_ERR) {
 338         goto close;
 339     }
 340
 341     if (p->size == p->length) {
 342         gpointer t = NULL;
 343         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
 344             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
 345         }
 346         if (t == NULL) {
 347             /* ignore truncated output */
 348             gchar buf[GUEST_EXEC_IO_SIZE];
 349
 350             p->truncated = true;
 351             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
 352                                               &bytes_read, NULL);
 353             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 354                 goto close;
 355             }
 356
 357             return true;
 358         }
 359         p->size += GUEST_EXEC_IO_SIZE;
 360         p->data = t;
 361     }
 362
 363     /* Calling read API once.
 364      * On next available data our callback will be called again */
 365     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
 366             p->size - p->length, &bytes_read, NULL);
 367     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 368         goto close;
 369     }
 370
 371     p->length += bytes_read;
 372
 373     return true;
 374
 375 close:
 376     g_io_channel_shutdown(ch, true, NULL);
 377     g_io_channel_unref(ch);
 378     atomic_mb_set(&p->closed, true);
 379     return false;
 380 }
 381
 382 GuestExec *qmp_guest_exec(const char *path,
 383                        bool has_arg, strList *arg,
 384                        bool has_env, strList *env,
 385                        bool has_input_data, const char *input_data,
 386                        bool has_capture_output, bool capture_output,
 387                        Error **err)
 388 {
 389     GPid pid;
 390     GuestExec *ge = NULL;
 391     GuestExecInfo *gei;
 392     char **argv, **envp;
 393     strList arglist;
 394     gboolean ret;
 395     GError *gerr = NULL;
 396     gint in_fd, out_fd, err_fd;
 397     GIOChannel *in_ch, *out_ch, *err_ch;
 398     GSpawnFlags flags;
 399     bool has_output = (has_capture_output && capture_output);
 400     uint8_t *input = NULL;
 401     size_t ninput = 0;
 402
 403     arglist.value = (char *)path;
 404     arglist.next = has_arg ? arg : NULL;
 405
 406     if (has_input_data) {
 407         input = qbase64_decode(input_data, -1, &ninput, err);
 408         if (!input) {
 409             return NULL;
 410         }
 411     }
 412
 413     argv = guest_exec_get_args(&arglist, true);
 414     envp = has_env ? guest_exec_get_args(env, false) : NULL;
 415
 416     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD;
 417 #if GLIB_CHECK_VERSION(2, 33, 2)
 418     flags |= G_SPAWN_SEARCH_PATH_FROM_ENVP;
 419 #endif
 420     if (!has_output) {
 421         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
 422     }
 423
 424     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
 425             guest_exec_task_setup, NULL, &pid, has_input_data ? &in_fd : NULL,
 426             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
 427     if (!ret) {
 428         error_setg(err, QERR_QGA_COMMAND_FAILED, gerr->message);
 429         g_error_free(gerr);
 430         goto done;
 431     }
 432
 433     ge = g_new0(GuestExec, 1);
 434     ge->pid = gpid_to_int64(pid);
 435
 436     gei = guest_exec_info_add(pid);
 437     gei->has_output = has_output;
 438     g_child_watch_add(pid, guest_exec_child_watch, gei);
 439
 440     if (has_input_data) {
 441         gei->in.data = input;
 442         gei->in.size = ninput;
 443 #ifdef G_OS_WIN32
 444         in_ch = g_io_channel_win32_new_fd(in_fd);
 445 #else
 446         in_ch = g_io_channel_unix_new(in_fd);
 447 #endif
 448         g_io_channel_set_encoding(in_ch, NULL, NULL);
 449         g_io_channel_set_buffered(in_ch, false);
 450         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
 451         g_io_channel_set_close_on_unref(in_ch, true);
 452         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
 453     }
 454
 455     if (has_output) {
 456 #ifdef G_OS_WIN32
 457         out_ch = g_io_channel_win32_new_fd(out_fd);
 458         err_ch = g_io_channel_win32_new_fd(err_fd);
 459 #else
 460         out_ch = g_io_channel_unix_new(out_fd);
 461         err_ch = g_io_channel_unix_new(err_fd);
 462 #endif
 463         g_io_channel_set_encoding(out_ch, NULL, NULL);
 464         g_io_channel_set_encoding(err_ch, NULL, NULL);
 465         g_io_channel_set_buffered(out_ch, false);
 466         g_io_channel_set_buffered(err_ch, false);
 467         g_io_channel_set_close_on_unref(out_ch, true);
 468         g_io_channel_set_close_on_unref(err_ch, true);
 469         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
 470                 guest_exec_output_watch, &gei->out);
 471         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
 472                 guest_exec_output_watch, &gei->err);
 473     }
 474
 475 done:
 476     g_free(argv);
 477     g_free(envp);
 478
 479     return ge;
 480 }
 481
 482 /* Convert GuestFileWhence (either a raw integer or an enum value) into
 483  * the guest's SEEK_ constants.  */
 484 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
 485 {
 486     /* Exploit the fact that we picked values to match QGA_SEEK_*. */
 487     if (whence->type == QTYPE_QSTRING) {
 488         whence->type = QTYPE_QINT;
 489         whence->u.value = whence->u.name;
 490     }
 491     switch (whence->u.value) {
 492     case QGA_SEEK_SET:
 493         return SEEK_SET;
 494     case QGA_SEEK_CUR:
 495         return SEEK_CUR;
 496     case QGA_SEEK_END:
 497         return SEEK_END;
 498     }
 499     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
 500     return -1;
 501 }