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