qemu/qga/commands.c
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   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 */
  31void 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
  40int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
  41{
  42    ga_set_response_delimited(ga_state);
  43    return id;
  44}
  45
  46int64_t qmp_guest_sync(int64_t id, Error **errp)
  47{
  48    return id;
  49}
  50
  51void qmp_guest_ping(Error **errp)
  52{
  53    slog("guest-ping called");
  54}
  55
  56static 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
  73struct 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(&ga_commands, qmp_command_info, info);
  79    return info;
  80}
  81
  82struct GuestExecIOData {
  83    guchar *data;
  84    gsize size;
  85    gsize length;
  86    bool closed;
  87    bool truncated;
  88    const char *name;
  89};
  90typedef struct GuestExecIOData GuestExecIOData;
  91
  92struct 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};
 103typedef struct GuestExecInfo GuestExecInfo;
 104
 105static struct {
 106    QTAILQ_HEAD(, GuestExecInfo) processes;
 107} guest_exec_state = {
 108    .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
 109};
 110
 111static 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
 120static 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
 132static 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
 145GuestExecStatus *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(). */
 227static 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
 260static 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. */
 274static 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
 289static 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
 321done:
 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
 330static 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
 375close:
 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
 382GuestExec *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
 475done:
 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.  */
 484int 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}
 502