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
  18 /* Maximum captured guest-exec out_data/err_data - 16MB */
  19 #define GUEST_EXEC_MAX_OUTPUT (16*1024*1024)
  20 /* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
  21 #define GUEST_EXEC_IO_SIZE (4*1024)
  22
  23 /* Note: in some situations, like with the fsfreeze, logging may be
  24  * temporarilly disabled. if it is necessary that a command be able
  25  * to log for accounting purposes, check ga_logging_enabled() beforehand,
  26  * and use the QERR_QGA_LOGGING_DISABLED to generate an error
  27  */
  28 void slog(const gchar *fmt, ...)
  29 {
  30     va_list ap;
  31
  32     va_start(ap, fmt);
  33     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
  34     va_end(ap);
  35 }
  36
  37 int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
  38 {
  39     ga_set_response_delimited(ga_state);
  40     return id;
  41 }
  42
  43 int64_t qmp_guest_sync(int64_t id, Error **errp)
  44 {
  45     return id;
  46 }
  47
  48 void qmp_guest_ping(Error **errp)
  49 {
  50     slog("guest-ping called");
  51 }
  52
  53 static void qmp_command_info(QmpCommand *cmd, void *opaque)
  54 {
  55     GuestAgentInfo *info = opaque;
  56     GuestAgentCommandInfo *cmd_info;
  57     GuestAgentCommandInfoList *cmd_info_list;
  58
  59     cmd_info = g_new0(GuestAgentCommandInfo, 1);
  60     cmd_info->name = g_strdup(qmp_command_name(cmd));
  61     cmd_info->enabled = qmp_command_is_enabled(cmd);
  62     cmd_info->success_response = qmp_has_success_response(cmd);
  63
  64     cmd_info_list = g_new0(GuestAgentCommandInfoList, 1);
  65     cmd_info_list->value = cmd_info;
  66     cmd_info_list->next = info->supported_commands;
  67     info->supported_commands = cmd_info_list;
  68 }
  69
  70 struct GuestAgentInfo *qmp_guest_info(Error **errp)
  71 {
  72     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
  73
  74     info->version = g_strdup(QEMU_VERSION);
  75     qmp_for_each_command(qmp_command_info, info);
  76     return info;
  77 }
  78
  79 struct GuestExecIOData {
  80     guchar *data;
  81     gsize size;
  82     gsize length;
  83     gint closed;
  84     bool truncated;
  85     const char *name;
  86 };
  87 typedef struct GuestExecIOData GuestExecIOData;
  88
  89 struct GuestExecInfo {
  90     GPid pid;
  91     int64_t pid_numeric;
  92     gint status;
  93     bool has_output;
  94     gint finished;
  95     GuestExecIOData in;
  96     GuestExecIOData out;
  97     GuestExecIOData err;
  98     QTAILQ_ENTRY(GuestExecInfo) next;
  99 };
 100 typedef struct GuestExecInfo GuestExecInfo;
 101
 102 static struct {
 103     QTAILQ_HEAD(, GuestExecInfo) processes;
 104 } guest_exec_state = {
 105     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 106 };
 107
 108 static int64_t gpid_to_int64(GPid pid)
 109 {
 110 #ifdef G_OS_WIN32
 111     return GetProcessId(pid);
 112 #else
 113     return (int64_t)pid;
 114 #endif
 115 }
 116
 117 static GuestExecInfo *guest_exec_info_add(GPid pid)
 118 {
 119     GuestExecInfo *gei;
 120
 121     gei = g_new0(GuestExecInfo, 1);
 122     gei->pid = pid;
 123     gei->pid_numeric = gpid_to_int64(pid);
 124     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
 125
 126     return gei;
 127 }
 128
 129 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
 130 {
 131     GuestExecInfo *gei;
 132
 133     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
 134         if (gei->pid_numeric == pid_numeric) {
 135             return gei;
 136         }
 137     }
 138
 139     return NULL;
 140 }
 141
 142 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err)
 143 {
 144     GuestExecInfo *gei;
 145     GuestExecStatus *ges;
 146
 147     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
 148
 149     gei = guest_exec_info_find(pid);
 150     if (gei == NULL) {
 151         error_setg(err, QERR_INVALID_PARAMETER, "pid");
 152         return NULL;
 153     }
 154
 155     ges = g_new0(GuestExecStatus, 1);
 156
 157     bool finished = g_atomic_int_get(&gei->finished);
 158
 159     /* need to wait till output channels are closed
 160      * to be sure we captured all output at this point */
 161     if (gei->has_output) {
 162         finished = finished && g_atomic_int_get(&gei->out.closed);
 163         finished = finished && g_atomic_int_get(&gei->err.closed);
 164     }
 165
 166     ges->exited = finished;
 167     if (finished) {
 168         /* Glib has no portable way to parse exit status.
 169          * On UNIX, we can get either exit code from normal termination
 170          * or signal number.
 171          * On Windows, it is either the same exit code or the exception
 172          * value for an unhandled exception that caused the process
 173          * to terminate.
 174          * See MSDN for GetExitCodeProcess() and ntstatus.h for possible
 175          * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
 176          * References:
 177          *   https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
 178          *   https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
 179          */
 180 #ifdef G_OS_WIN32
 181         /* Additionally WIN32 does not provide any additional information
 182          * on whetherthe child exited or terminated via signal.
 183          * We use this simple range check to distingish application exit code
 184          * (usually value less then 256) and unhandled exception code with
 185          * ntstatus (always value greater then 0xC0000005). */
 186         if ((uint32_t)gei->status < 0xC0000000U) {
 187             ges->has_exitcode = true;
 188             ges->exitcode = gei->status;
 189         } else {
 190             ges->has_signal = true;
 191             ges->signal = gei->status;
 192         }
 193 #else
 194         if (WIFEXITED(gei->status)) {
 195             ges->has_exitcode = true;
 196             ges->exitcode = WEXITSTATUS(gei->status);
 197         } else if (WIFSIGNALED(gei->status)) {
 198             ges->has_signal = true;
 199             ges->signal = WTERMSIG(gei->status);
 200         }
 201 #endif
 202         if (gei->out.length > 0) {
 203             ges->has_out_data = true;
 204             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
 205             g_free(gei->out.data);
 206             ges->has_out_truncated = gei->out.truncated;
 207         }
 208
 209         if (gei->err.length > 0) {
 210             ges->has_err_data = true;
 211             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
 212             g_free(gei->err.data);
 213             ges->has_err_truncated = gei->err.truncated;
 214         }
 215
 216         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
 217         g_free(gei);
 218     }
 219
 220     return ges;
 221 }
 222
 223 /* Get environment variables or arguments array for execve(). */
 224 static char **guest_exec_get_args(const strList *entry, bool log)
 225 {
 226     const strList *it;
 227     int count = 1, i = 0;  /* reserve for NULL terminator */
 228     char **args;
 229     char *str; /* for logging array of arguments */
 230     size_t str_size = 1;
 231
 232     for (it = entry; it != NULL; it = it->next) {
 233         count++;
 234         str_size += 1 + strlen(it->value);
 235     }
 236
 237     str = g_malloc(str_size);
 238     *str = 0;
 239     args = g_malloc(count * sizeof(char *));
 240     for (it = entry; it != NULL; it = it->next) {
 241         args[i++] = it->value;
 242         pstrcat(str, str_size, it->value);
 243         if (it->next) {
 244             pstrcat(str, str_size, " ");
 245         }
 246     }
 247     args[i] = NULL;
 248
 249     if (log) {
 250         slog("guest-exec called: \"%s\"", str);
 251     }
 252     g_free(str);
 253
 254     return args;
 255 }
 256
 257 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
 258 {
 259     GuestExecInfo *gei = (GuestExecInfo *)data;
 260
 261     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
 262             (int32_t)gpid_to_int64(pid), (uint32_t)status);
 263
 264     gei->status = status;
 265     gei->finished = true;
 266
 267     g_spawn_close_pid(pid);
 268 }
 269
 270 /** Reset ignored signals back to default. */
 271 static void guest_exec_task_setup(gpointer data)
 272 {
 273 #if !defined(G_OS_WIN32)
 274     struct sigaction sigact;
 275
 276     memset(&sigact, 0, sizeof(struct sigaction));
 277     sigact.sa_handler = SIG_DFL;
 278
 279     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
 280         slog("sigaction() failed to reset child process's SIGPIPE: %s",
 281              strerror(errno));
 282     }
 283 #endif
 284 }
 285
 286 static gboolean guest_exec_input_watch(GIOChannel *ch,
 287         GIOCondition cond, gpointer p_)
 288 {
 289     GuestExecIOData *p = (GuestExecIOData *)p_;
 290     gsize bytes_written = 0;
 291     GIOStatus status;
 292     GError *gerr = NULL;
 293
 294     /* nothing left to write */
 295     if (p->size == p->length) {
 296         goto done;
 297     }
 298
 299     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
 300             p->size - p->length, &bytes_written, &gerr);
 301
 302     /* can be not 0 even if not G_IO_STATUS_NORMAL */
 303     if (bytes_written != 0) {
 304         p->length += bytes_written;
 305     }
 306
 307     /* continue write, our callback will be called again */
 308     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
 309         return true;
 310     }
 311
 312     if (gerr) {
 313         g_warning("qga: i/o error writing to input_data channel: %s",
 314                 gerr->message);
 315         g_error_free(gerr);
 316     }
 317
 318 done:
 319     g_io_channel_shutdown(ch, true, NULL);
 320     g_io_channel_unref(ch);
 321     g_atomic_int_set(&p->closed, 1);
 322     g_free(p->data);
 323
 324     return false;
 325 }
 326
 327 static gboolean guest_exec_output_watch(GIOChannel *ch,
 328         GIOCondition cond, gpointer p_)
 329 {
 330     GuestExecIOData *p = (GuestExecIOData *)p_;
 331     gsize bytes_read;
 332     GIOStatus gstatus;
 333
 334     if (cond == G_IO_HUP || cond == G_IO_ERR) {
 335         goto close;
 336     }
 337
 338     if (p->size == p->length) {
 339         gpointer t = NULL;
 340         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
 341             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
 342         }
 343         if (t == NULL) {
 344             /* ignore truncated output */
 345             gchar buf[GUEST_EXEC_IO_SIZE];
 346
 347             p->truncated = true;
 348             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
 349                                               &bytes_read, NULL);
 350             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 351                 goto close;
 352             }
 353
 354             return true;
 355         }
 356         p->size += GUEST_EXEC_IO_SIZE;
 357         p->data = t;
 358     }
 359
 360     /* Calling read API once.
 361      * On next available data our callback will be called again */
 362     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
 363             p->size - p->length, &bytes_read, NULL);
 364     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
 365         goto close;
 366     }
 367
 368     p->length += bytes_read;
 369
 370     return true;
 371
 372 close:
 373     g_io_channel_unref(ch);
 374     g_atomic_int_set(&p->closed, 1);
 375     return false;
 376 }
 377
 378 GuestExec *qmp_guest_exec(const char *path,
 379                        bool has_arg, strList *arg,
 380                        bool has_env, strList *env,
 381                        bool has_input_data, const char *input_data,
 382                        bool has_capture_output, bool capture_output,
 383                        Error **err)
 384 {
 385     GPid pid;
 386     GuestExec *ge = NULL;
 387     GuestExecInfo *gei;
 388     char **argv, **envp;
 389     strList arglist;
 390     gboolean ret;
 391     GError *gerr = NULL;
 392     gint in_fd, out_fd, err_fd;
 393     GIOChannel *in_ch, *out_ch, *err_ch;
 394     GSpawnFlags flags;
 395     bool has_output = (has_capture_output && capture_output);
 396
 397     arglist.value = (char *)path;
 398     arglist.next = has_arg ? arg : NULL;
 399
 400     argv = guest_exec_get_args(&arglist, true);
 401     envp = guest_exec_get_args(has_env ? env : NULL, false);
 402
 403     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD;
 404     if (!has_output) {
 405         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
 406     }
 407
 408     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
 409             guest_exec_task_setup, NULL, &pid, has_input_data ? &in_fd : NULL,
 410             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
 411     if (!ret) {
 412         error_setg(err, QERR_QGA_COMMAND_FAILED, gerr->message);
 413         g_error_free(gerr);
 414         goto done;
 415     }
 416
 417     ge = g_new0(GuestExec, 1);
 418     ge->pid = gpid_to_int64(pid);
 419
 420     gei = guest_exec_info_add(pid);
 421     gei->has_output = has_output;
 422     g_child_watch_add(pid, guest_exec_child_watch, gei);
 423
 424     if (has_input_data) {
 425         gei->in.data = g_base64_decode(input_data, &gei->in.size);
 426 #ifdef G_OS_WIN32
 427         in_ch = g_io_channel_win32_new_fd(in_fd);
 428 #else
 429         in_ch = g_io_channel_unix_new(in_fd);
 430 #endif
 431         g_io_channel_set_encoding(in_ch, NULL, NULL);
 432         g_io_channel_set_buffered(in_ch, false);
 433         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
 434         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
 435     }
 436
 437     if (has_output) {
 438 #ifdef G_OS_WIN32
 439         out_ch = g_io_channel_win32_new_fd(out_fd);
 440         err_ch = g_io_channel_win32_new_fd(err_fd);
 441 #else
 442         out_ch = g_io_channel_unix_new(out_fd);
 443         err_ch = g_io_channel_unix_new(err_fd);
 444 #endif
 445         g_io_channel_set_encoding(out_ch, NULL, NULL);
 446         g_io_channel_set_encoding(err_ch, NULL, NULL);
 447         g_io_channel_set_buffered(out_ch, false);
 448         g_io_channel_set_buffered(err_ch, false);
 449         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
 450                 guest_exec_output_watch, &gei->out);
 451         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
 452                 guest_exec_output_watch, &gei->err);
 453     }
 454
 455 done:
 456     g_free(argv);
 457     g_free(envp);
 458
 459     return ge;
 460 }