1 files changed, 179 insertions, 0 deletions

diff --git a/libblkid/include/debug.h b/libblkid/include/debug.h
new file mode 100644
index 000000000..0229ab329
--- /dev/null
+++ b/libblkid/include/debug.h
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2014 Ondrej Oprala <ooprala@redhat.com>
+ * Copyright (C) 2014 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be distributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+#ifndef UTIL_LINUX_DEBUG_H
+#define UTIL_LINUX_DEBUG_H
+
+
+/*
+ * util-linux debug macros
+ *
+ * The debug stuff is based on <name>_debug_mask that controls what outputs is
+ * expected. The mask is usually initialized by <NAME>_DEBUG= env.variable
+ *
+ * After successful initialization the flag <PREFIX>_DEBUG_INIT is always set
+ * to the mask (this flag is required). The <PREFIX> is usually library API
+ * prefix (e.g. MNT_) or program name (e.g. CFDISK_)
+ *
+ * In the code is possible to use
+ *
+ *	DBG(FOO, ul_debug("this is output for foo"));
+ *
+ * where for the FOO has to be defined <PREFIX>_DEBUG_FOO.
+ *
+ * It's possible to initialize the mask by comma delimited strings with
+ * subsystem names (e.g. "LIBMOUNT_DEBUG=options,tab"). In this case is
+ * necessary to define mask names array. This functionality is optional.
+ *
+ * It's stringly recommended to use UL_* macros to define/declare/use
+ * the debug stuff.
+ *
+ * See disk-utils/cfdisk.c: cfdisk_init_debug()  for programs debug
+ *  or libmount/src/init.c: mnt_init_debug()     for library debug
+ *
+ */
+
+#include <stdarg.h>
+#include <string.h>
+
+struct ul_debug_maskname {
+	const char *name;
+	int mask;
+	const char *help;
+};
+#define UL_DEBUG_EMPTY_MASKNAMES {{ NULL, 0, NULL }}
+#define UL_DEBUG_DEFINE_MASKNAMES(m) static const struct ul_debug_maskname m ## _masknames[]
+#define UL_DEBUG_MASKNAMES(m)	m ## _masknames
+
+#define UL_DEBUG_DEFINE_MASK(m) int m ## _debug_mask
+#define UL_DEBUG_DECLARE_MASK(m) extern UL_DEBUG_DEFINE_MASK(m)
+
+/* p - flag prefix, m - flag postfix */
+#define UL_DEBUG_DEFINE_FLAG(p, m) p ## m
+
+/* l - library name, p - flag prefix, m - flag postfix, x - function */
+#define __UL_DBG(l, p, m, x) \
+	do { \
+		if ((p ## m) & l ## _debug_mask) { \
+			fprintf(stderr, "%d: %s: %8s: ", getpid(), # l, # m); \
+			x; \
+		} \
+	} while (0)
+
+#define __UL_DBG_CALL(l, p, m, x) \
+	do { \
+		if ((p ## m) & l ## _debug_mask) { \
+			x; \
+		} \
+	} while (0)
+
+#define __UL_DBG_FLUSH(l, p) \
+	do { \
+		if (l ## _debug_mask && \
+		    l ## _debug_mask != p ## INIT) { \
+			fflush(stderr); \
+		} \
+	} while (0)
+
+
+#define __UL_INIT_DEBUG(lib, pref, mask, env) \
+	do { \
+		if (lib ## _debug_mask & pref ## INIT) \
+		; \
+		else if (!mask) { \
+			char *str = getenv(# env); \
+			if (str) \
+				lib ## _debug_mask = ul_debug_parse_envmask(lib ## _masknames, str); \
+		} else \
+			lib ## _debug_mask = mask; \
+		lib ## _debug_mask |= pref ## INIT; \
+	} while (0)
+
+
+static inline void __attribute__ ((__format__ (__printf__, 1, 2)))
+ul_debug(const char *mesg, ...)
+{
+	va_list ap;
+	va_start(ap, mesg);
+	vfprintf(stderr, mesg, ap);
+	va_end(ap);
+	fputc('\n', stderr);
+}
+
+static inline void __attribute__ ((__format__ (__printf__, 2, 3)))
+ul_debugobj(void *handler, const char *mesg, ...)
+{
+	va_list ap;
+
+	if (handler)
+		fprintf(stderr, "[%p]: ", handler);
+	va_start(ap, mesg);
+	vfprintf(stderr, mesg, ap);
+	va_end(ap);
+	fputc('\n', stderr);
+}
+
+static inline int ul_debug_parse_envmask(
+			const struct ul_debug_maskname flagnames[],
+			const char *mask)
+{
+	int res;
+	char *ptr;
+
+	/* let's check for a numeric mask first */
+	res = strtoul(mask, &ptr, 0);
+
+	/* perhaps it's a comma-separated string? */
+	if (ptr && *ptr && flagnames && flagnames[0].name) {
+		char *msbuf, *ms, *name;
+		res = 0;
+
+		ms = msbuf = strdup(mask);
+		if (!ms)
+			return res;
+
+		while ((name = strtok_r(ms, ",", &ptr))) {
+			const struct ul_debug_maskname *d;
+			ms = ptr;
+
+			for (d = flagnames; d && d->name; d++) {
+				if (strcmp(name, d->name) == 0) {
+					res |= d->mask;
+					break;
+				}
+			}
+			/* nothing else we can do by OR-ing the mask */
+			if (res == 0xffff)
+				break;
+		}
+		free(msbuf);
+	} else if (ptr && strcmp(ptr, "all") == 0)
+		res = 0xffff;
+
+	return res;
+}
+
+static inline void ul_debug_print_masks(
+			const char *env,
+			const struct ul_debug_maskname flagnames[])
+{
+	const struct ul_debug_maskname *d;
+
+	if (!flagnames)
+		return;
+
+	fprintf(stderr, "Available \"%s=<name>[,...]|<mask>\" debug masks:\n",
+			env);
+	for (d = flagnames; d && d->name; d++) {
+		if (!d->help)
+			continue;
+		fprintf(stderr, "   %-8s [0x%04x] : %s\n",
+				d->name, d->mask, d->help);
+	}
+}
+
+#endif /* UTIL_LINUX_DEBUG_H */