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qemu/qga/commands.c

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/*
* QEMU Guest Agent common/cross-platform command implementations
*
* Copyright IBM Corp. 2012
*
* Authors:
* Michael Roth <mdroth@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qga/guest-agent-core.h"
#include "qga-qmp-commands.h"
#include "qapi/qmp/qerror.h"
#include "qemu/base64.h"
#include "qemu/cutils.h"
#include "qemu/atomic.h"
/* Maximum captured guest-exec out_data/err_data - 16MB */
#define GUEST_EXEC_MAX_OUTPUT (16*1024*1024)
/* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
#define GUEST_EXEC_IO_SIZE (4*1024)
/* Note: in some situations, like with the fsfreeze, logging may be
* temporarilly disabled. if it is necessary that a command be able
* to log for accounting purposes, check ga_logging_enabled() beforehand,
* and use the QERR_QGA_LOGGING_DISABLED to generate an error
*/
void slog(const gchar *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
va_end(ap);
}
int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
{
ga_set_response_delimited(ga_state);
return id;
}
int64_t qmp_guest_sync(int64_t id, Error **errp)
{
return id;
}
void qmp_guest_ping(Error **errp)
{
slog("guest-ping called");
}
static void qmp_command_info(QmpCommand *cmd, void *opaque)
{
GuestAgentInfo *info = opaque;
GuestAgentCommandInfo *cmd_info;
GuestAgentCommandInfoList *cmd_info_list;
cmd_info = g_new0(GuestAgentCommandInfo, 1);
cmd_info->name = g_strdup(qmp_command_name(cmd));
cmd_info->enabled = qmp_command_is_enabled(cmd);
cmd_info->success_response = qmp_has_success_response(cmd);
cmd_info_list = g_new0(GuestAgentCommandInfoList, 1);
cmd_info_list->value = cmd_info;
cmd_info_list->next = info->supported_commands;
info->supported_commands = cmd_info_list;
}
struct GuestAgentInfo *qmp_guest_info(Error **errp)
{
GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
info->version = g_strdup(QEMU_VERSION);
qmp_for_each_command(qmp_command_info, info);
return info;
}
struct GuestExecIOData {
guchar *data;
gsize size;
gsize length;
bool closed;
bool truncated;
const char *name;
};
typedef struct GuestExecIOData GuestExecIOData;
struct GuestExecInfo {
GPid pid;
int64_t pid_numeric;
gint status;
bool has_output;
bool finished;
GuestExecIOData in;
GuestExecIOData out;
GuestExecIOData err;
QTAILQ_ENTRY(GuestExecInfo) next;
};
typedef struct GuestExecInfo GuestExecInfo;
static struct {
QTAILQ_HEAD(, GuestExecInfo) processes;
} guest_exec_state = {
.processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
};
static int64_t gpid_to_int64(GPid pid)
{
#ifdef G_OS_WIN32
return GetProcessId(pid);
#else
return (int64_t)pid;
#endif
}
static GuestExecInfo *guest_exec_info_add(GPid pid)
{
GuestExecInfo *gei;
gei = g_new0(GuestExecInfo, 1);
gei->pid = pid;
gei->pid_numeric = gpid_to_int64(pid);
QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
return gei;
}
static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
{
GuestExecInfo *gei;
QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
if (gei->pid_numeric == pid_numeric) {
return gei;
}
}
return NULL;
}
GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err)
{
GuestExecInfo *gei;
GuestExecStatus *ges;
slog("guest-exec-status called, pid: %u", (uint32_t)pid);
gei = guest_exec_info_find(pid);
if (gei == NULL) {
error_setg(err, QERR_INVALID_PARAMETER, "pid");
return NULL;
}
ges = g_new0(GuestExecStatus, 1);
bool finished = atomic_mb_read(&gei->finished);
/* need to wait till output channels are closed
* to be sure we captured all output at this point */
if (gei->has_output) {
finished = finished && atomic_mb_read(&gei->out.closed);
finished = finished && atomic_mb_read(&gei->err.closed);
}
ges->exited = finished;
if (finished) {
/* Glib has no portable way to parse exit status.
* On UNIX, we can get either exit code from normal termination
* or signal number.
* On Windows, it is either the same exit code or the exception
* value for an unhandled exception that caused the process
* to terminate.
* See MSDN for GetExitCodeProcess() and ntstatus.h for possible
* well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
* References:
* https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
* https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
*/
#ifdef G_OS_WIN32
/* Additionally WIN32 does not provide any additional information
* on whether the child exited or terminated via signal.
* We use this simple range check to distinguish application exit code
* (usually value less then 256) and unhandled exception code with
* ntstatus (always value greater then 0xC0000005). */
if ((uint32_t)gei->status < 0xC0000000U) {
ges->has_exitcode = true;
ges->exitcode = gei->status;
} else {
ges->has_signal = true;
ges->signal = gei->status;
}
#else
if (WIFEXITED(gei->status)) {
ges->has_exitcode = true;
ges->exitcode = WEXITSTATUS(gei->status);
} else if (WIFSIGNALED(gei->status)) {
ges->has_signal = true;
ges->signal = WTERMSIG(gei->status);
}
#endif
if (gei->out.length > 0) {
ges->has_out_data = true;
ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
g_free(gei->out.data);
ges->has_out_truncated = gei->out.truncated;
}
if (gei->err.length > 0) {
ges->has_err_data = true;
ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
g_free(gei->err.data);
ges->has_err_truncated = gei->err.truncated;
}
QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
g_free(gei);
}
return ges;
}
/* Get environment variables or arguments array for execve(). */
static char **guest_exec_get_args(const strList *entry, bool log)
{
const strList *it;
int count = 1, i = 0; /* reserve for NULL terminator */
char **args;
char *str; /* for logging array of arguments */
size_t str_size = 1;
for (it = entry; it != NULL; it = it->next) {
count++;
str_size += 1 + strlen(it->value);
}
str = g_malloc(str_size);
*str = 0;
args = g_malloc(count * sizeof(char *));
for (it = entry; it != NULL; it = it->next) {
args[i++] = it->value;
pstrcat(str, str_size, it->value);
if (it->next) {
pstrcat(str, str_size, " ");
}
}
args[i] = NULL;
if (log) {
slog("guest-exec called: \"%s\"", str);
}
g_free(str);
return args;
}
static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
{
GuestExecInfo *gei = (GuestExecInfo *)data;
g_debug("guest_exec_child_watch called, pid: %d, status: %u",
(int32_t)gpid_to_int64(pid), (uint32_t)status);
gei->status = status;
atomic_mb_set(&gei->finished, true);
g_spawn_close_pid(pid);
}
/** Reset ignored signals back to default. */
static void guest_exec_task_setup(gpointer data)
{
#if !defined(G_OS_WIN32)
struct sigaction sigact;
memset(&sigact, 0, sizeof(struct sigaction));
sigact.sa_handler = SIG_DFL;
if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
slog("sigaction() failed to reset child process's SIGPIPE: %s",
strerror(errno));
}
#endif
}
static gboolean guest_exec_input_watch(GIOChannel *ch,
GIOCondition cond, gpointer p_)
{
GuestExecIOData *p = (GuestExecIOData *)p_;
gsize bytes_written = 0;
GIOStatus status;
GError *gerr = NULL;
/* nothing left to write */
if (p->size == p->length) {
goto done;
}
status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
p->size - p->length, &bytes_written, &gerr);
/* can be not 0 even if not G_IO_STATUS_NORMAL */
if (bytes_written != 0) {
p->length += bytes_written;
}
/* continue write, our callback will be called again */
if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
return true;
}
if (gerr) {
g_warning("qga: i/o error writing to input_data channel: %s",
gerr->message);
g_error_free(gerr);
}
done:
g_io_channel_shutdown(ch, true, NULL);
g_io_channel_unref(ch);
atomic_mb_set(&p->closed, true);
g_free(p->data);
return false;
}
static gboolean guest_exec_output_watch(GIOChannel *ch,
GIOCondition cond, gpointer p_)
{
GuestExecIOData *p = (GuestExecIOData *)p_;
gsize bytes_read;
GIOStatus gstatus;
if (cond == G_IO_HUP || cond == G_IO_ERR) {
goto close;
}
if (p->size == p->length) {
gpointer t = NULL;
if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
}
if (t == NULL) {
/* ignore truncated output */
gchar buf[GUEST_EXEC_IO_SIZE];
p->truncated = true;
gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
&bytes_read, NULL);
if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
goto close;
}
return true;
}
p->size += GUEST_EXEC_IO_SIZE;
p->data = t;
}
/* Calling read API once.
* On next available data our callback will be called again */
gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
p->size - p->length, &bytes_read, NULL);
if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
goto close;
}
p->length += bytes_read;
return true;
close:
g_io_channel_shutdown(ch, true, NULL);
g_io_channel_unref(ch);
atomic_mb_set(&p->closed, true);
return false;
}
GuestExec *qmp_guest_exec(const char *path,
bool has_arg, strList *arg,
bool has_env, strList *env,
bool has_input_data, const char *input_data,
bool has_capture_output, bool capture_output,
Error **err)
{
GPid pid;
GuestExec *ge = NULL;
GuestExecInfo *gei;
char **argv, **envp;
strList arglist;
gboolean ret;
GError *gerr = NULL;
gint in_fd, out_fd, err_fd;
GIOChannel *in_ch, *out_ch, *err_ch;
GSpawnFlags flags;
bool has_output = (has_capture_output && capture_output);
uint8_t *input = NULL;
size_t ninput = 0;
arglist.value = (char *)path;
arglist.next = has_arg ? arg : NULL;
if (has_input_data) {
input = qbase64_decode(input_data, -1, &ninput, err);
if (!input) {
return NULL;
}
}
argv = guest_exec_get_args(&arglist, true);
envp = has_env ? guest_exec_get_args(env, false) : NULL;
flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD;
#if GLIB_CHECK_VERSION(2, 33, 2)
flags |= G_SPAWN_SEARCH_PATH_FROM_ENVP;
#endif
if (!has_output) {
flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
}
ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
guest_exec_task_setup, NULL, &pid, has_input_data ? &in_fd : NULL,
has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
if (!ret) {
error_setg(err, QERR_QGA_COMMAND_FAILED, gerr->message);
g_error_free(gerr);
goto done;
}
ge = g_new0(GuestExec, 1);
ge->pid = gpid_to_int64(pid);
gei = guest_exec_info_add(pid);
gei->has_output = has_output;
g_child_watch_add(pid, guest_exec_child_watch, gei);
if (has_input_data) {
gei->in.data = input;
gei->in.size = ninput;
#ifdef G_OS_WIN32
in_ch = g_io_channel_win32_new_fd(in_fd);
#else
in_ch = g_io_channel_unix_new(in_fd);
#endif
g_io_channel_set_encoding(in_ch, NULL, NULL);
g_io_channel_set_buffered(in_ch, false);
g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
g_io_channel_set_close_on_unref(in_ch, true);
g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
}
if (has_output) {
#ifdef G_OS_WIN32
out_ch = g_io_channel_win32_new_fd(out_fd);
err_ch = g_io_channel_win32_new_fd(err_fd);
#else
out_ch = g_io_channel_unix_new(out_fd);
err_ch = g_io_channel_unix_new(err_fd);
#endif
g_io_channel_set_encoding(out_ch, NULL, NULL);
g_io_channel_set_encoding(err_ch, NULL, NULL);
g_io_channel_set_buffered(out_ch, false);
g_io_channel_set_buffered(err_ch, false);
g_io_channel_set_close_on_unref(out_ch, true);
g_io_channel_set_close_on_unref(err_ch, true);
g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
guest_exec_output_watch, &gei->out);
g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
guest_exec_output_watch, &gei->err);
}
done:
g_free(argv);
g_free(envp);
return ge;
}
/* Convert GuestFileWhence (either a raw integer or an enum value) into
* the guest's SEEK_ constants. */
int ga_parse_whence(GuestFileWhence *whence, Error **errp)
{
/* Exploit the fact that we picked values to match QGA_SEEK_*. */
if (whence->type == QTYPE_QSTRING) {
whence->type = QTYPE_QINT;
whence->u.value = whence->u.name;
}
switch (whence->u.value) {
case QGA_SEEK_SET:
return SEEK_SET;
case QGA_SEEK_CUR:
return SEEK_CUR;
case QGA_SEEK_END:
return SEEK_END;
}
error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
return -1;
}
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