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