perf target: Introduce perf_target_errno

The perf_target_errno enumerations are used to indicate specific error
cases on perf target operations. It'd help libperf being a more generic
library.
Signed-off-by: Namhyung Kim <namhyung.kim@lge.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1336367344-28071-4-git-send-email-namhyung.kim@lge.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/target.c

@@ -10,36 +10,47 @@
 #include "debug.h"
 
 
-void perf_target__validate(struct perf_target *target)
+enum perf_target_errno perf_target__validate(struct perf_target *target)
 {
+	enum perf_target_errno ret = PERF_ERRNO_TARGET__SUCCESS;
+
 	if (target->pid)
 		target->tid = target->pid;
 
 	/* CPU and PID are mutually exclusive */
 	if (target->tid && target->cpu_list) {
-		ui__warning("WARNING: PID switch overriding CPU\n");
-		sleep(1);
 		target->cpu_list = NULL;
+		if (ret == PERF_ERRNO_TARGET__SUCCESS)
+			ret = PERF_ERRNO_TARGET__PID_OVERRIDE_CPU;
 	}
 
 	/* UID and PID are mutually exclusive */
 	if (target->tid && target->uid_str) {
-		ui__warning("PID/TID switch overriding UID\n");
-		sleep(1);
 		target->uid_str = NULL;
+		if (ret == PERF_ERRNO_TARGET__SUCCESS)
+			ret = PERF_ERRNO_TARGET__PID_OVERRIDE_UID;
 	}
 
 	/* UID and CPU are mutually exclusive */
 	if (target->uid_str && target->cpu_list) {
-		ui__warning("UID switch overriding CPU\n");
-		sleep(1);
 		target->cpu_list = NULL;
+		if (ret == PERF_ERRNO_TARGET__SUCCESS)
+			ret = PERF_ERRNO_TARGET__UID_OVERRIDE_CPU;
 	}
 
-	/* PID/UID and SYSTEM are mutually exclusive */
-	if ((target->tid || target->uid_str) && target->system_wide) {
-		ui__warning("PID/TID/UID switch overriding CPU\n");
-		sleep(1);
+	/* PID and SYSTEM are mutually exclusive */
+	if (target->tid && target->system_wide) {
 		target->system_wide = false;
+		if (ret == PERF_ERRNO_TARGET__SUCCESS)
+			ret = PERF_ERRNO_TARGET__PID_OVERRIDE_SYSTEM;
 	}
+
+	/* UID and SYSTEM are mutually exclusive */
+	if (target->uid_str && target->system_wide) {
+		target->system_wide = false;
+		if (ret == PERF_ERRNO_TARGET__SUCCESS)
+			ret = PERF_ERRNO_TARGET__UID_OVERRIDE_SYSTEM;
+	}
+
+	return ret;
 }

tools/perf/util/target.h

@@ -13,6 +13,29 @@ struct perf_target {
 	bool	     system_wide;
 };
 
-void perf_target__validate(struct perf_target *target);
+enum perf_target_errno {
+	PERF_ERRNO_TARGET__SUCCESS		= 0,
+
+	/*
+	 * Choose an arbitrary negative big number not to clash with standard
+	 * errno since SUS requires the errno has distinct positive values.
+	 * See 'Issue 6' in the link below.
+	 *
+	 * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+	 */
+	__PERF_ERRNO_TARGET__START		= -10000,
+
+
+	/* for perf_target__validate() */
+	PERF_ERRNO_TARGET__PID_OVERRIDE_CPU	= __PERF_ERRNO_TARGET__START,
+	PERF_ERRNO_TARGET__PID_OVERRIDE_UID,
+	PERF_ERRNO_TARGET__UID_OVERRIDE_CPU,
+	PERF_ERRNO_TARGET__PID_OVERRIDE_SYSTEM,
+	PERF_ERRNO_TARGET__UID_OVERRIDE_SYSTEM,
+
+	__PERF_ERRNO_TARGET__END,
+};
+
+enum perf_target_errno perf_target__validate(struct perf_target *target);
 
 #endif /* _PERF_TARGET_H */