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qga: guest-exec simple stdin/stdout/stderr redirection 

Implemented with base64-encoded strings in qga json protocol.
Glib portable GIOChannel is used for data I/O.

Optinal stdin parameter of guest-exec command is now used as
stdin content for spawned subprocess.

If capture-output bool flag is specified, guest-exec redirects out/err
file descriptiors internally to pipes and collects subprocess
output.

Guest-exe-status is modified to return this collected data to requestor
in base64 encoding.

Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
* switch from 'struct GuestIOExecData' to 'GuestIOExecData'
* s/TRUE/true/g, s/FALSE/false/g for gboolean return values
* s/inp_data/input_data/
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
This commit is contained in:
Yuri Pudgorodskiy 2015-10-13 18:41:23 +03:00 committed by Michael Roth
parent f74df9bfce
commit a1853dca74
2 changed files with 187 additions and 9 deletions
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189
qga/commands.c
View File

@ -15,6 +15,11 @@
#include "qga-qmp-commands.h"
#include "qapi/qmp/qerror.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,
@ -71,11 +76,25 @@ struct GuestAgentInfo *qmp_guest_info(Error **errp)
return info;
}
struct GuestExecIOData {
guchar *data;
gsize size;
gsize length;
gint closed;
bool truncated;
const char *name;
};
typedef struct GuestExecIOData GuestExecIOData;
struct GuestExecInfo {
GPid pid;
int64_t pid_numeric;
gint status;
bool finished;
bool has_output;
gint finished;
GuestExecIOData in;
GuestExecIOData out;
GuestExecIOData err;
QTAILQ_ENTRY(GuestExecInfo) next;
};
typedef struct GuestExecInfo GuestExecInfo;
@ -134,9 +153,18 @@ GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err)
}
ges = g_new0(GuestExecStatus, 1);
ges->exited = gei->finished;
if (gei->finished) {
bool finished = g_atomic_int_get(&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 && g_atomic_int_get(&gei->out.closed);
finished = finished && g_atomic_int_get(&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.
@ -171,6 +199,20 @@ GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err)
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);
}
@ -241,6 +283,98 @@ static void guest_exec_task_setup(gpointer data)
#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);
g_atomic_int_set(&p->closed, 1);
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_unref(ch);
g_atomic_int_set(&p->closed, 1);
return false;
}
GuestExec *qmp_guest_exec(const char *path,
bool has_arg, strList *arg,
bool has_env, strList *env,
@ -255,6 +389,10 @@ GuestExec *qmp_guest_exec(const char *path,
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);
arglist.value = (char *)path;
arglist.next = has_arg ? arg : NULL;
@ -262,11 +400,14 @@ GuestExec *qmp_guest_exec(const char *path,
argv = guest_exec_get_args(&arglist, true);
envp = guest_exec_get_args(has_env ? env : NULL, false);
ret = g_spawn_async_with_pipes(NULL, argv, envp,
G_SPAWN_SEARCH_PATH |
G_SPAWN_DO_NOT_REAP_CHILD |
G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL,
guest_exec_task_setup, NULL, &pid, NULL, NULL, NULL, &gerr);
flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD;
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);
@ -277,8 +418,40 @@ GuestExec *qmp_guest_exec(const char *path,
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 = g_base64_decode(input_data, &gei->in.size);
#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_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_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);

7
qga/qapi-schema.json
View File

@ -941,12 +941,17 @@
# @err-data: #optional base64-encoded stderr of the process
# Note: @out-data and @err-data are present only
# if 'capture-output' was specified for 'guest-exec'
# @out-truncated: #optional true if stdout was not fully captured
# due to size limitation.
# @err-truncated: #optional true if stderr was not fully captured
# due to size limitation.
#
# Since: 2.5
##
{ 'struct': 'GuestExecStatus',
'data': { 'exited': 'bool', '*exitcode': 'int', '*signal': 'int',
'*out-data': 'str', '*err-data': 'str' }}
'*out-data': 'str', '*err-data': 'str',
'*out-truncated': 'bool', '*err-truncated': 'bool' }}
##
# @guest-exec-status
#