On 05/09/2012 08:22 AM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange@redhat.com>
Sometimes it is useful to see the callpath for log messages. This change enhances the log filter syntax so that stck traces
s/stck/stack/
can be show by setting '1:+NAME' instead of '1:NAME'.
Cool.
* docs/logging.html.in: Document new syntax * configure.ac: Check for execinfo.h * src/util/logging.c, src/util/logging.h: Add support for stack traces
Of course, this seems to be Linux-only, but still useful.
+++ b/docs/logging.html.in @@ -114,8 +114,10 @@ </h3> <p>The syntax for filters and outputs is the same for both types of variables.</p> - <p>The format for a filter is:</p> - <pre>x:name</pre> + <p>The format for a filter is one of:</p> + <pre> + x:name (log message only) + x:+name (log message + stack trace)</pre>
Does x:+name error out on systems where tracing is not built in, or does it silently fall back to x:name?
@@ -538,6 +546,7 @@ static int virLogFiltersCheck(const char *input) { for (i = 0;i < virLogNbFilters;i++) { if (strstr(input, virLogFilters[i].match)) { ret = virLogFilters[i].priority; + *flags = virLogFilters[i].flags;
Is the double space intentional?
+ +static void virLogStackTraceToFd(int fd) +{ +#ifdef HAVE_EXECINFO_H + void *array[100]; + int size; + +#define STRIP_DEPTH 3 + + size = backtrace(array, sizeof(array)/sizeof(array[0]));
Write the second argument as ARRAY_CARDINALITY(array).
+ backtrace_symbols_fd(array + STRIP_DEPTH, size - STRIP_DEPTH, fd); + ignore_value(safewrite(fd, "\n", 1)); +#else + const char *msg = "stack trace not available on this platform"; + ignore_value(safewrite(fd, msg, strlen(msg)));
Is this a one-time error message, printed on first use, or will it appear on every log message? -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org