Add "print debug foo" function safe to use in signal handlers, example:

_rthread_debug(3, "foo = %s", foo);
where output is to stderr and will only be printed if the current
debug level is >= 3.   Messages with a debug level of 0 are always
printed.  The level can be set from the environment (not enabled yet)
or with gdb by modifying variable _rthread_debug_level.
"Fine with me" -Otto

1 files changed, 82 insertions, 0 deletions

diff --git a/lib/librthread/rthread_debug.c b/lib/librthread/rthread_debug.c
new file mode 100644
index 00000000000..1111a615707
--- /dev/null
+++ b/lib/librthread/rthread_debug.c
@@ -0,0 +1,82 @@
+/* $OpenBSD: rthread_debug.c,v 1.1 2005/12/31 21:40:43 marc Exp $ */
+/* $snafu: rthread_debug.c,v 1.2 2004/12/09 18:41:44 marc Exp $ */
+
+/* PUBLIC DOMAIN: No Rights Reserved. Marco S Hyman <marc@snafu.org> */
+
+#define _POSIX_THREADS
+
+#include <sys/param.h>
+#include <sys/mman.h>
+#include <sys/wait.h>
+
+#include <machine/spinlock.h>
+
+#include <pthread.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "rthread.h"
+
+int _rthread_debug_level;
+
+/*
+ * Note: messages truncated at 255 characters.   Could use vasprintf,
+ * but don't want to use malloc here so the function can be used
+ * in signal handlers.
+ */
+#define MAX_MSG_LEN 256
+#define RTHREAD_ENV_DEBUG	"RTHREAD_DEBUG"
+
+/*
+ * format and send output to stderr if the given "level" is less than or
+ * equal to the current debug level.   Messages with a level <= 0 will
+ * always be printed.
+ */
+void
+_rthread_debug(int level, const char *fmt, ...)
+{
+	char msg[MAX_MSG_LEN];
+	char *p;
+	int cnt;
+	ssize_t c;
+
+	if (_rthread_debug_level >= level) {
+		va_list ap;
+		va_start(ap, fmt);
+		cnt = vsnprintf(msg, MAX_MSG_LEN, fmt, ap);
+		va_end(ap);
+		if (cnt > MAX_MSG_LEN - 1)
+			cnt = MAX_MSG_LEN - 1;
+		p = msg;
+		do {
+			c = write(STDERR_FILENO, p, cnt);
+			if (c == -1)
+				break;
+			if (c != cnt)
+				sched_yield();
+			p += c;
+			cnt -= c;
+		} while (cnt > 0);
+	}
+}
+
+/*
+ * set the debug level from an environment string.  Bogus values are
+ * silently ignored.
+ */
+void
+_rthread_debug_init(void)
+{
+	char *envp;
+	char *rem;
+
+	envp = getenv(RTHREAD_ENV_DEBUG);
+	if (envp) {
+		_rthread_debug_level = (int) strtol(envp, &rem, 0);
+		if (*rem || _rthread_debug_level < 0)
+			_rthread_debug_level = 0;
+	}
+}