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Make QEMU text monitor parsing more robust

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The QEMU 0.10.0 release (and possibly other 0.10.x) has a bug where
it sometimes/often forgets to display the initial monitor greeting
line, soley printing a (qemu).  This in turn confuses the text
console parsing because it has a '(qemu)' it is not expecting. The
confusion results in a negative malloc. Bad things follow.

This re-writes the text console handling to be more robust. The key
idea is that it should only look for a (qemu), once it has seen the
original command echo'd back. This ensures it'll skip the bogus stray
(qemu) with broken QEMUs.

* src/qemu/qemu_monitor.c: Add some (disabled) debug code
* src/qemu/qemu_monitor_text.c: Re-write way command replies
  are detected
This commit is contained in:
Daniel P. Berrange 2009-12-08 18:05:02 +00:00
parent 8e7d14953c
commit cce1998a64
2 changed files with 95 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
src/qemu/qemu_monitor.c
View File

@ -39,6 +39,8 @@
#define VIR_FROM_THIS VIR_FROM_QEMU
#define QEMU_DEBUG_RAW_IO 0
struct _qemuMonitor {
virMutex lock;
virCond notify;
@ -163,6 +165,24 @@ char *qemuMonitorEscapeShell(const char *in)
}
#if QEMU_DEBUG_RAW_IO
#include <c-ctype.h>
static char * qemuMonitorEscapeNonPrintable(const char *text)
{
int i;
virBuffer buf = VIR_BUFFER_INITIALIZER;
for (i = 0 ; text[i] != '\0' ; i++) {
if (c_isprint(text[i]) ||
text[i] == '\n' ||
(text[i] == '\r' && text[i+1] == '\n'))
virBufferVSprintf(&buf,"%c", text[i]);
else
virBufferVSprintf(&buf, "0x%02x", text[i]);
}
return virBufferContentAndReset(&buf);
}
#endif
void qemuMonitorLock(qemuMonitorPtr mon)
{
virMutexLock(&mon->lock);
@ -282,7 +302,15 @@ qemuMonitorIOProcess(qemuMonitorPtr mon)
if (mon->msg && mon->msg->txOffset == mon->msg->txLength)
msg = mon->msg;
#if QEMU_DEBUG_RAW_IO
char *str1 = qemuMonitorEscapeNonPrintable(msg ? msg->txBuffer : "");
char *str2 = qemuMonitorEscapeNonPrintable(mon->buffer);
VIR_ERROR("Process %d %p %p [[[[%s]]][[[%s]]]", (int)mon->bufferOffset, mon->msg, msg, str1, str2);
VIR_FREE(str1);
VIR_FREE(str2);
#else
VIR_DEBUG("Process %d", (int)mon->bufferOffset);
#endif
if (mon->json)
len = qemuMonitorJSONIOProcess(mon,
mon->buffer, mon->bufferOffset,

102
src/qemu/qemu_monitor_text.c
View File

@ -94,46 +94,78 @@ int qemuMonitorTextIOProcess(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
/* Look for a non-zero reply followed by prompt */
if (msg && !msg->finished) {
const char *end;
char *start = NULL;
char *end = NULL;
char *skip;
/* We might get a prompt for a password */
end = strstr(data + used, PASSWORD_PROMPT);
if (end) {
VIR_DEBUG("Woooo passwowrd [%s]", data + used);
if (msg->passwordHandler) {
size_t consumed;
/* Try and handle the prompt */
if (msg->passwordHandler(mon, msg,
data + used,
len - used,
msg->passwordOpaque) < 0)
return -1;
/* Skip over prompt now */
consumed = (end + strlen(PASSWORD_PROMPT))
- (data + used);
used += consumed;
} else {
errno = EACCES;
return -1;
/* If we're here, we've already sent the command. We now
* strip the trailing '\r' because it makes the matching
* code that follows a little easier ie we can just strstr()
* for the original command
*/
if (msg->txLength > 0) {
char *tmp;
if ((tmp = strchr(msg->txBuffer, '\r'))) {
*tmp = '\0';
}
}
/* We use the arrival of BASIC_PROMPT to detect when we've got a
* complete reply available from a command */
end = strstr(data + used, BASIC_PROMPT);
if (end) {
/* QEMU echos the command back to us, full of control
* character junk that we don't want. Fortunately this
* is all terminated by LINE_ENDING, so we can easily
* skip over the control character junk */
const char *start = strstr(data + used, LINE_ENDING);
if (!start)
start = data + used;
else
start += strlen(LINE_ENDING);
int want = end - start;
/* QEMU echos the command back to us, full of control
* character junk that we don't want. We have to skip
* over this junk by looking for the first complete
* repetition of our command. Then we can look for
* the prompt that is supposed to follow
*
* NB, we can't optimize by immediately looking for
* LINE_ENDING, because QEMU 0.10 has bad problems
* when initially connecting where it might write a
* prompt in the wrong place. So we must not look
* for LINE_ENDING, or BASIC_PROMPT until we've
* seen our original command echod.
*/
skip = strstr(data + used, msg->txBuffer);
/* After the junk we should have a line ending... */
if (skip) {
start = strstr(skip + strlen(msg->txBuffer), LINE_ENDING);
}
/* ... then our command reply data, following by a (qemu) prompt */
if (start) {
char *passwd;
start += strlen(LINE_ENDING);
/* We might get a prompt for a password before the (qemu) prompt */
passwd = strstr(start, PASSWORD_PROMPT);
if (passwd) {
VIR_DEBUG("Seen a passwowrd prompt [%s]", data + used);
if (msg->passwordHandler) {
int i;
/* Try and handle the prompt */
if (msg->passwordHandler(mon, msg,
start,
passwd - start + strlen(PASSWORD_PROMPT),
msg->passwordOpaque) < 0)
return -1;
/* Blank out the password prompt so we don't re-trigger
* if we have to go back to sleep for more I/O */
for (i = 0 ; i < strlen(PASSWORD_PROMPT) ; i++)
start[i] = ' ';
/* Handled, so skip forward over password prompt */
start = passwd;
} else {
errno = EACCES;
return -1;
}
}
end = strstr(start, BASIC_PROMPT);
}
if (start && end) {
int want = end - start;
/* Annoyingly some commands may not have any reply data
* at all upon success, but since we've detected the
* BASIC_PROMPT we can reasonably reliably cope */