On Fri, Mar 02, 2007 at 03:06:56PM +0000, Mark McLoughlin wrote:
Hi Dan,
On Fri, 2007-03-02 at 14:35 +0000, Daniel P. Berrange wrote:
+static int qemudOpenMonitor(struct qemud_vm *vm, const char *monitor) {
#define MONITOR_POLL_TIMEOUT 5
+ int monfd; + char buffer[1024]; + int got = 0; + + if (!(monfd = open(monitor, O_RDWR))) { + return -1; + } + if (qemudSetCloseExec(monfd) < 0) + goto error; + if (qemudSetNonBlock(monfd) < 0) + goto error; + + /* Consume & discard the initial greeting */ + for(;;) { + int ret; + + ret = read(monfd, buffer+got, sizeof(buffer)-got-1);
What happens if the buffer fills up ?
Sorry, wrong version of the patch - the for(;;) should have been while (got < (sizeof(buffer)-1)) { I'll repost the correct patch when I've done of the other fixes.
+ if (ret == 0) + goto error; + if (ret < 0) { + struct pollfd fd = { .fd = monfd, .events = POLLIN }; + if (errno != EAGAIN && + errno != EINTR) + goto error; + + ret = poll(&fd, 1, 5);
ret = poll(&fd, 1, MONITOR_POLL_TIMEOUT);
Giving up after 5 milliseconds? Are we that afraid of commitment?
Again, wrong patch - it should have been 5 seconds.
+static int qemudWaitForMonitor(struct qemud_vm *vm) {
We don't set an error in here, so how about returning the appropriate errno from the function?
I'll add in some error reporting.
+ if (sscanf(tmp, "char device redirected to %19s", monitor) == 1) {
Path length of 100, maximum field with of 19? That's all rather voodooish ... hope about strstr() to find it, buffer length of PATH_MAX and then just strncpy()? Also, it'd be nice to split that out into e.g. qemudMonitorPathFromStr(buffer, monitorPath, PATH_MAX)
I'll have a go at splitting it out.
+ if (qemudOpenMonitor(vm, monitor) < 0) + return -1; + return 0; + } + tmp = index(tmp, '\n');
index() is a bit odd, why not strstr() ?
Well we're only looking for a single character match - index() is for single characters, strstr() is for strings.
+static int qemudNextFreeVNCPort(struct qemud_server *server ATTRIBUTE_UNUSED) {
I don't really know the context, but it'd be much nicer if we could just QEMU find a free port itself and then we query the port - e.g. the obvious race condition.
Currently QEMU can't auto-allocate itself a patch - I'm planning to port the Xen auto-allocation patch to mainline QEMU. Until then, this code is better than the the current situation, even though there is an obvious race.
+ if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) == 0)
Um, why not bind() (with SO_REUSEADDR)?
No particular reason - either will work just fine. Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|