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libvirt/tools/virsh-console.c
Nikolay Shirokovskiy 29f2b5248c tools: console: pass stream/fd errors to user 
If the console was disconnected due to a connection problem or a problem on the
server side it is convinient to provide the cause to the user. If the error
come from the API then the error is saved in a virsh global variable. However,
since success is returned from virshRunConsole after we reach the waiting stage,
then the error is never reported. Let's track the error in the event loop.

Next after failure we do a cleanup and this cleanup can overwrite
root cause. Thus let's save root cause immediately and then set it to
virsh error after all cleanup is done.

Since we'll be sending the error to the consumer, each failure path from
the event handlers needs to be augmented to provide what error generated
the failure.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@virtuozzo.com>
2019-04-04 10:36:04 +03:00

519 lines
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/*
* virsh-console.c: A dumb serial console client
*
* Copyright (C) 2007-2008, 2010-2014 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#ifndef WIN32
# include <sys/types.h>
# include <sys/stat.h>
# include <fcntl.h>
# include <termios.h>
# include <poll.h>
# include <unistd.h>
# include <signal.h>
# include <c-ctype.h>
# include "internal.h"
# include "virsh.h"
# include "virsh-console.h"
# include "virlog.h"
# include "virfile.h"
# include "viralloc.h"
# include "virthread.h"
# include "virerror.h"
VIR_LOG_INIT("tools.virsh-console");
/*
* Convert given character to control character.
* Basically, we assume ASCII, and take lower 6 bits.
*/
# define CONTROL(c) ((c) ^ 0x40)
# define VIR_FROM_THIS VIR_FROM_NONE
struct virConsoleBuffer {
size_t length;
size_t offset;
char *data;
};
typedef struct virConsole virConsole;
typedef virConsole *virConsolePtr;
struct virConsole {
virObjectLockable parent;
virStreamPtr st;
bool quit;
virCond cond;
int stdinWatch;
int stdoutWatch;
struct virConsoleBuffer streamToTerminal;
struct virConsoleBuffer terminalToStream;
char escapeChar;
virError error;
};
static virClassPtr virConsoleClass;
static void virConsoleDispose(void *obj);
static int
virConsoleOnceInit(void)
{
if (!VIR_CLASS_NEW(virConsole, virClassForObjectLockable()))
return -1;
return 0;
}
VIR_ONCE_GLOBAL_INIT(virConsole);
static void
virConsoleHandleSignal(int sig ATTRIBUTE_UNUSED)
{
}
static void
virConsoleShutdown(virConsolePtr con)
{
virErrorPtr err = virGetLastError();
if (con->error.code == VIR_ERR_OK && err)
virCopyLastError(&con->error);
if (con->st) {
virStreamEventRemoveCallback(con->st);
virStreamAbort(con->st);
virStreamFree(con->st);
con->st = NULL;
}
VIR_FREE(con->streamToTerminal.data);
VIR_FREE(con->terminalToStream.data);
if (con->stdinWatch != -1)
virEventRemoveHandle(con->stdinWatch);
if (con->stdoutWatch != -1)
virEventRemoveHandle(con->stdoutWatch);
con->stdinWatch = -1;
con->stdoutWatch = -1;
if (!con->quit) {
con->quit = true;
virCondSignal(&con->cond);
}
}
static void
virConsoleDispose(void *obj)
{
virConsolePtr con = obj;
if (con->st)
virStreamFree(con->st);
virCondDestroy(&con->cond);
virResetError(&con->error);
}
static void
virConsoleEventOnStream(virStreamPtr st,
int events, void *opaque)
{
virConsolePtr con = opaque;
virObjectLock(con);
/* we got late event after console was shutdown */
if (!con->st)
goto cleanup;
if (events & VIR_STREAM_EVENT_READABLE) {
size_t avail = con->streamToTerminal.length -
con->streamToTerminal.offset;
int got;
if (avail < 1024) {
if (VIR_REALLOC_N(con->streamToTerminal.data,
con->streamToTerminal.length + 1024) < 0) {
virConsoleShutdown(con);
goto cleanup;
}
con->streamToTerminal.length += 1024;
avail += 1024;
}
got = virStreamRecv(st,
con->streamToTerminal.data +
con->streamToTerminal.offset,
avail);
if (got == -2)
goto cleanup; /* blocking */
if (got <= 0) {
if (got == 0)
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("console stream EOF"));
virConsoleShutdown(con);
goto cleanup;
}
con->streamToTerminal.offset += got;
if (con->streamToTerminal.offset)
virEventUpdateHandle(con->stdoutWatch,
VIR_EVENT_HANDLE_WRITABLE);
}
if (events & VIR_STREAM_EVENT_WRITABLE &&
con->terminalToStream.offset) {
ssize_t done;
size_t avail;
done = virStreamSend(con->st,
con->terminalToStream.data,
con->terminalToStream.offset);
if (done == -2)
goto cleanup; /* blocking */
if (done < 0) {
virConsoleShutdown(con);
goto cleanup;
}
memmove(con->terminalToStream.data,
con->terminalToStream.data + done,
con->terminalToStream.offset - done);
con->terminalToStream.offset -= done;
avail = con->terminalToStream.length - con->terminalToStream.offset;
if (avail > 1024) {
ignore_value(VIR_REALLOC_N(con->terminalToStream.data,
con->terminalToStream.offset + 1024));
con->terminalToStream.length = con->terminalToStream.offset + 1024;
}
}
if (!con->terminalToStream.offset)
virStreamEventUpdateCallback(con->st,
VIR_STREAM_EVENT_READABLE);
if (events & VIR_STREAM_EVENT_ERROR ||
events & VIR_STREAM_EVENT_HANGUP) {
virConsoleShutdown(con);
}
cleanup:
virObjectUnlock(con);
}
static void
virConsoleEventOnStdin(int watch ATTRIBUTE_UNUSED,
int fd ATTRIBUTE_UNUSED,
int events,
void *opaque)
{
virConsolePtr con = opaque;
virObjectLock(con);
/* we got late event after console was shutdown */
if (!con->st)
goto cleanup;
if (events & VIR_EVENT_HANDLE_READABLE) {
size_t avail = con->terminalToStream.length -
con->terminalToStream.offset;
int got;
if (avail < 1024) {
if (VIR_REALLOC_N(con->terminalToStream.data,
con->terminalToStream.length + 1024) < 0) {
virConsoleShutdown(con);
goto cleanup;
}
con->terminalToStream.length += 1024;
avail += 1024;
}
got = read(fd,
con->terminalToStream.data +
con->terminalToStream.offset,
avail);
if (got < 0) {
if (errno != EAGAIN) {
virReportSystemError(errno, "%s", _("cannot read from stdin"));
virConsoleShutdown(con);
}
goto cleanup;
}
if (got == 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on stdin"));
virConsoleShutdown(con);
goto cleanup;
}
if (con->terminalToStream.data[con->terminalToStream.offset] == con->escapeChar) {
virConsoleShutdown(con);
goto cleanup;
}
con->terminalToStream.offset += got;
if (con->terminalToStream.offset)
virStreamEventUpdateCallback(con->st,
VIR_STREAM_EVENT_READABLE |
VIR_STREAM_EVENT_WRITABLE);
}
if (events & VIR_EVENT_HANDLE_ERROR) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("IO error on stdin"));
virConsoleShutdown(con);
goto cleanup;
}
if (events & VIR_EVENT_HANDLE_HANGUP) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on stdin"));
virConsoleShutdown(con);
goto cleanup;
}
cleanup:
virObjectUnlock(con);
}
static void
virConsoleEventOnStdout(int watch ATTRIBUTE_UNUSED,
int fd,
int events,
void *opaque)
{
virConsolePtr con = opaque;
virObjectLock(con);
/* we got late event after console was shutdown */
if (!con->st)
goto cleanup;
if (events & VIR_EVENT_HANDLE_WRITABLE &&
con->streamToTerminal.offset) {
ssize_t done;
size_t avail;
done = write(fd,
con->streamToTerminal.data,
con->streamToTerminal.offset);
if (done < 0) {
if (errno != EAGAIN) {
virReportSystemError(errno, "%s", _("cannot write to stdout"));
virConsoleShutdown(con);
}
goto cleanup;
}
memmove(con->streamToTerminal.data,
con->streamToTerminal.data + done,
con->streamToTerminal.offset - done);
con->streamToTerminal.offset -= done;
avail = con->streamToTerminal.length - con->streamToTerminal.offset;
if (avail > 1024) {
ignore_value(VIR_REALLOC_N(con->streamToTerminal.data,
con->streamToTerminal.offset + 1024));
con->streamToTerminal.length = con->streamToTerminal.offset + 1024;
}
}
if (!con->streamToTerminal.offset)
virEventUpdateHandle(con->stdoutWatch, 0);
if (events & VIR_EVENT_HANDLE_ERROR) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("IO error stdout"));
virConsoleShutdown(con);
goto cleanup;
}
if (events & VIR_EVENT_HANDLE_HANGUP) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on stdout"));
virConsoleShutdown(con);
goto cleanup;
}
cleanup:
virObjectUnlock(con);
}
static virConsolePtr
virConsoleNew(void)
{
virConsolePtr con;
if (virConsoleInitialize() < 0)
return NULL;
if (!(con = virObjectNew(virConsoleClass)))
return NULL;
if (virCondInit(&con->cond) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("cannot initialize console condition"));
goto error;
}
con->stdinWatch = -1;
con->stdoutWatch = -1;
return con;
error:
virObjectUnref(con);
return NULL;
}
static char
virshGetEscapeChar(const char *s)
{
if (*s == '^')
return CONTROL(c_toupper(s[1]));
return *s;
}
int
virshRunConsole(vshControl *ctl,
virDomainPtr dom,
const char *dev_name,
unsigned int flags)
{
virConsolePtr con = NULL;
virshControlPtr priv = ctl->privData;
int ret = -1;
struct sigaction old_sigquit;
struct sigaction old_sigterm;
struct sigaction old_sigint;
struct sigaction old_sighup;
struct sigaction old_sigpipe;
struct sigaction sighandler = {.sa_handler = virConsoleHandleSignal,
.sa_flags = SA_SIGINFO };
sigemptyset(&sighandler.sa_mask);
/* Put STDIN into raw mode so that stuff typed does not echo to the screen
* (the TTY reads will result in it being echoed back already), and also
* ensure Ctrl-C, etc is blocked, and misc other bits */
if (vshTTYMakeRaw(ctl, true) < 0)
goto resettty;
if (!(con = virConsoleNew()))
goto resettty;
virObjectLock(con);
/* Trap all common signals so that we can safely restore the original
* terminal settings on STDIN before the process exits - people don't like
* being left with a messed up terminal ! */
sigaction(SIGQUIT, &sighandler, &old_sigquit);
sigaction(SIGTERM, &sighandler, &old_sigterm);
sigaction(SIGINT, &sighandler, &old_sigint);
sigaction(SIGHUP, &sighandler, &old_sighup);
sigaction(SIGPIPE, &sighandler, &old_sigpipe);
con->escapeChar = virshGetEscapeChar(priv->escapeChar);
con->st = virStreamNew(virDomainGetConnect(dom),
VIR_STREAM_NONBLOCK);
if (!con->st)
goto cleanup;
if (virDomainOpenConsole(dom, dev_name, con->st, flags) < 0)
goto cleanup;
virObjectRef(con);
if ((con->stdinWatch = virEventAddHandle(STDIN_FILENO,
VIR_EVENT_HANDLE_READABLE,
virConsoleEventOnStdin,
con,
virObjectFreeCallback)) < 0) {
virObjectUnref(con);
goto cleanup;
}
virObjectRef(con);
if ((con->stdoutWatch = virEventAddHandle(STDOUT_FILENO,
0,
virConsoleEventOnStdout,
con,
virObjectFreeCallback)) < 0) {
virObjectUnref(con);
goto cleanup;
}
virObjectRef(con);
if (virStreamEventAddCallback(con->st,
VIR_STREAM_EVENT_READABLE,
virConsoleEventOnStream,
con,
virObjectFreeCallback) < 0) {
virObjectUnref(con);
goto cleanup;
}
while (!con->quit) {
if (virCondWait(&con->cond, &con->parent.lock) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("unable to wait on console condition"));
goto cleanup;
}
}
if (con->error.code == VIR_ERR_OK)
ret = 0;
cleanup:
virConsoleShutdown(con);
if (ret < 0) {
vshResetLibvirtError();
virSetError(&con->error);
vshSaveLibvirtHelperError();
}
virObjectUnlock(con);
virObjectUnref(con);
/* Restore original signal handlers */
sigaction(SIGQUIT, &old_sigquit, NULL);
sigaction(SIGTERM, &old_sigterm, NULL);
sigaction(SIGINT, &old_sigint, NULL);
sigaction(SIGHUP, &old_sighup, NULL);
sigaction(SIGPIPE, &old_sigpipe, NULL);
resettty:
/* Put STDIN back into the (sane?) state we found
it in before starting */
vshTTYRestore(ctl);
return ret;
}
#endif /* !WIN32 */
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