Add support for debug tracing.

Use P11_KIT_DEBUG=xxx environment variable to enable tracing. Must
have been built without --disable-debug option.

P11_KIT_DEBUG can (at this point) be one of these values:
 all
 help
 conf
 lib

1 files changed, 136 insertions, 0 deletions

diff --git a/p11-kit/debug.c b/p11-kit/debug.c
new file mode 100644
index 0000000..a7b75ad
--- /dev/null
+++ b/p11-kit/debug.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) 2011 Collabora Ltd.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *     * Redistributions of source code must retain the above
+ *       copyright notice, this list of conditions and the
+ *       following disclaimer.
+ *     * Redistributions in binary form must reproduce the
+ *       above copyright notice, this list of conditions and
+ *       the following disclaimer in the documentation and/or
+ *       other materials provided with the distribution.
+ *     * The names of contributors to this software may not be
+ *       used to endorse or promote products derived from this
+ *       software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ *
+ * CONTRIBUTORS
+ *  Stef Walter <stef@memberwebs.com>
+ */
+
+#include "config.h"
+
+#include "debug.h"
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+struct DebugKey {
+	const char *name;
+	int value;
+};
+
+static struct DebugKey debug_keys[] = {
+	{ "lib", DEBUG_LIB },
+	{ "conf", DEBUG_CONF },
+	{ 0, }
+};
+
+pthread_mutex_t debug_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/* global variable exported in debug.h */
+int debug_current_flags = ~0;
+
+static int
+parse_environ_flags (void)
+{
+	const char *env;
+	int result = 0;
+	const char *p;
+	const char *q;
+	int i;
+
+	env = getenv ("P11_KIT_DEBUG");
+	if (!env)
+		return 0;
+
+	if (strcmp (env, "all") == 0) {
+		for (i = 0; debug_keys[i].name; i++)
+			result |= debug_keys[i].value;
+
+	} else if (strcmp (env, "help") == 0) {
+		fprintf (stderr, "Supported debug values:");
+		for (i = 0; debug_keys[i].name; i++)
+			fprintf (stderr, " %s", debug_keys[i].name);
+		fprintf (stderr, "\n");
+
+	} else {
+		p = env;
+		while (*p) {
+			q = strpbrk (p, ":;, \t");
+			if (!q)
+				q = p + strlen (p);
+
+			for (i = 0; debug_keys[i].name; i++) {
+				if (q - p == strlen (debug_keys[i].name) &&
+				    strncmp (debug_keys[i].name, p, q - p) == 0)
+					result |= debug_keys[i].value;
+			}
+
+			p = q;
+			if (*p)
+				p++;
+		}
+	}
+
+	return result;
+}
+
+void
+debug_message (int flag, const char *format, ...)
+{
+	static int initialized_flags = 0;
+	char buffer[512];
+	va_list args;
+
+	pthread_mutex_lock (&debug_mutex);
+
+	/*
+	 * This is not thread-safe, but it's not really the end of the
+	 * world if it happens more than once.
+	 */
+	if (!initialized_flags) {
+		initialized_flags = 1;
+		debug_current_flags = parse_environ_flags ();
+	}
+
+	if (flag & debug_current_flags) {
+		va_start (args, format);
+		vsnprintf (buffer, sizeof (buffer), format, args);
+		buffer[sizeof (buffer) -1] = 0;
+		va_end (args);
+		fprintf (stderr, "(p11-kit:%d) %s\n", getpid(), buffer);
+	}
+
+	pthread_mutex_unlock (&debug_mutex);
+}