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libvirt/tools/virsh-console.c
Andrea Bolognani 16d37076be virsh: Show 'connected to console' message later 
Right now, we display the message before actually attempting
to connect to the VM console. That operation, however, can
fail for a number of reasons: for example, is the VM doesn't
have a serial device, the output ends up looking like

  $ virsh console cirros
  Connected to domain 'cirros'
  Escape character is ^] (Ctrl + ])
  error: internal error: cannot find character device <null>

The initial message is misleading. Change things so that it's
only printed if we actually successfully connected to the VM
console.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2024-04-02 18:26:35 +02:00

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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 "internal.h"
# include "virsh.h"
# include "virsh-console.h"
# include "virsh-util.h"
# include "virlog.h"
# include "viralloc.h"
# include "virthread.h"
# include "virerror.h"
# include "virobject.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;
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 virClass *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 G_GNUC_UNUSED)
{
}
static void
virConsoleShutdown(virConsole *con,
bool graceful)
{
virErrorPtr err = virGetLastError();
if (con->error.code == VIR_ERR_OK && err)
virCopyLastError(&con->error);
if (con->st) {
int rc;
virStreamEventRemoveCallback(con->st);
if (graceful)
rc = virStreamFinish(con->st);
else
rc = virStreamAbort(con->st);
if (rc < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("cannot terminate console stream"));
}
g_clear_pointer(&con->st, virshStreamFree);
}
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)
{
virConsole *con = obj;
virshStreamFree(con->st);
virCondDestroy(&con->cond);
virResetError(&con->error);
}
static void
virConsoleEventOnStream(virStreamPtr st,
int events, void *opaque)
{
virConsole *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) {
VIR_REALLOC_N(con->streamToTerminal.data,
con->streamToTerminal.length + 1024);
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) {
virConsoleShutdown(con, got == 0);
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, false);
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) {
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, false);
}
cleanup:
virObjectUnlock(con);
}
static void
virConsoleEventOnStdin(int watch G_GNUC_UNUSED,
int fd G_GNUC_UNUSED,
int events,
void *opaque)
{
virConsole *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) {
VIR_REALLOC_N(con->terminalToStream.data,
con->terminalToStream.length + 1024);
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, false);
}
goto cleanup;
}
if (got == 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on stdin"));
virConsoleShutdown(con, false);
goto cleanup;
}
if (con->terminalToStream.data[con->terminalToStream.offset] == con->escapeChar) {
virConsoleShutdown(con, true);
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, false);
goto cleanup;
}
if (events & VIR_EVENT_HANDLE_HANGUP) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on stdin"));
virConsoleShutdown(con, false);
goto cleanup;
}
cleanup:
virObjectUnlock(con);
}
static void
virConsoleEventOnStdout(int watch G_GNUC_UNUSED,
int fd,
int events,
void *opaque)
{
virConsole *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, /* sc_avoid_write */
con->streamToTerminal.data,
con->streamToTerminal.offset);
if (done < 0) {
if (errno != EAGAIN) {
virReportSystemError(errno, "%s", _("cannot write to stdout"));
virConsoleShutdown(con, false);
}
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) {
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, false);
goto cleanup;
}
if (events & VIR_EVENT_HANDLE_HANGUP) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("EOF on stdout"));
virConsoleShutdown(con, false);
goto cleanup;
}
cleanup:
virObjectUnlock(con);
}
static virConsole *
virConsoleNew(void)
{
virConsole *con;
if (virConsoleInitialize() < 0)
return NULL;
if (!(con = virObjectLockableNew(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(g_ascii_toupper(s[1]));
return *s;
}
int
virshRunConsole(vshControl *ctl,
virDomainPtr dom,
const char *dev_name,
const bool resume_domain,
unsigned int flags)
{
virConsole *con = NULL;
virshControl *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);
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;
vshPrintExtra(ctl, _("Connected to domain '%1$s'\n"), virDomainGetName(dom));
vshPrintExtra(ctl, _("Escape character is %1$s"), priv->escapeChar);
if (priv->escapeChar[0] == '^')
vshPrintExtra(ctl, " (Ctrl + %c)", priv->escapeChar[1]);
vshPrintExtra(ctl, "\n");
fflush(stdout);
/* 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 cleanup;
virObjectRef(con);
if ((con->stdinWatch = virEventAddHandle(STDIN_FILENO,
VIR_EVENT_HANDLE_READABLE,
virConsoleEventOnStdin,
con,
virObjectUnref)) < 0) {
virObjectUnref(con);
goto cleanup;
}
virObjectRef(con);
if ((con->stdoutWatch = virEventAddHandle(STDOUT_FILENO,
0,
virConsoleEventOnStdout,
con,
virObjectUnref)) < 0) {
virObjectUnref(con);
goto cleanup;
}
virObjectRef(con);
if (virStreamEventAddCallback(con->st,
VIR_STREAM_EVENT_READABLE,
virConsoleEventOnStream,
con,
virObjectUnref) < 0) {
virObjectUnref(con);
goto cleanup;
}
if (resume_domain) {
if (virDomainResume(dom) != 0) {
vshError(ctl, _("Failed to resume domain '%1$s'"),
virDomainGetName(dom));
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, ret == 0);
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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