Add utility functions

Move helpers out to separate files.
Mostly borrowed from perf

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

Makefile

@@ -2,6 +2,7 @@ PROGRAM	= kvm
 
 OBJS	+= kvm.o
 OBJS	+= cpu.o
+OBJS	+= util.o
 
 CFLAGS	+= -Iinclude
 

kvm.c

@@ -12,6 +12,8 @@
 #include <stdio.h>
 #include <fcntl.h>
 
+#include "util.h"
+
 /*
  * Compatibility code. Remove this when we move to tools/kvm.
  */
@@ -31,24 +33,6 @@ struct kvm {
 	struct kvm_regs		regs;
 };
 
-static void die_perror(const char *s)
-{
-	perror(s);
-	exit(1);
-}
-
-static void die(const char *format, ...)
-{
-        va_list ap;
-
-        va_start(ap, format);
-        vprintf(format, ap);
-        va_end(ap);
-
-        printf("\n");
-	exit(1);
-}
-
 static inline bool kvm__supports_extension(struct kvm *self, unsigned int extension)
 {
 	int ret;

util.c

@@ -0,0 +1,62 @@
+/*
+ * Taken from perf which in turn take it from GIT
+ */
+
+#include "util.h"
+
+static void report(const char *prefix, const char *err, va_list params)
+{
+	char msg[1024];
+	vsnprintf(msg, sizeof(msg), err, params);
+	fprintf(stderr, " %s%s\n", prefix, msg);
+}
+
+static NORETURN void die_builtin(const char *err, va_list params)
+{
+	report(" Fatal: ", err, params);
+	exit(128);
+}
+
+static void error_builtin(const char *err, va_list params)
+{
+	report(" Error: ", err, params);
+}
+
+static void warn_builtin(const char *warn, va_list params)
+{
+	report(" Warning: ", warn, params);
+}
+
+void die(const char *err, ...)
+{
+	va_list params;
+
+	va_start(params, err);
+	die_builtin(err, params);
+	va_end(params);
+}
+
+int error(const char *err, ...)
+{
+	va_list params;
+
+	va_start(params, err);
+	error_builtin(err, params);
+	va_end(params);
+	return -1;
+}
+
+void warning(const char *warn, ...)
+{
+	va_list params;
+
+	va_start(params, warn);
+	warn_builtin(warn, params);
+	va_end(params);
+}
+
+void die_perror(const char *s)
+{
+	perror(s);
+	exit(1);
+}

util.h

@@ -0,0 +1,44 @@
+#ifndef UTIL_H_
+#define UTIL_H_
+
+/*
+ * Some bits are stolen from perf tool :)
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/param.h>
+#include <sys/types.h>
+
+#ifdef __GNUC__
+#define NORETURN __attribute__((__noreturn__))
+#else
+#define NORETURN
+#ifndef __attribute__
+#define __attribute__(x)
+#endif
+#endif
+
+#define __stringify_1(x)	#x
+#define __stringify(x)		__stringify_1(x)
+
+extern void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2)));
+extern void die_perror(const char *s) NORETURN;
+extern int error(const char *err, ...) __attribute__((format (printf, 1, 2)));
+extern void warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
+extern void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN);
+
+#define DIE_IF(cnd)						\
+do {								\
+	if (cnd)						\
+	die(" at (" __FILE__ ":" __stringify(__LINE__) "): "	\
+		__stringify(cnd) "\n");				\
+} while (0)
+
+#endif /* UTIL_H_ */