perf target: Separate parse_uid into its own function

JIRA: https://issues.redhat.com/browse/RHEL-78200

upstream
========
commit 5ddf4c3
Author: Ian Rogers <irogers@google.com>
Date: Wed Jun 4 10:45:36 2025 -0700

description
===========
Allow parse_uid to be called without a struct target. Rather than have
two errors, remove TARGET_ERRNO__USER_NOT_FOUND and use
TARGET_ERRNO__INVALID_UID as the handling is identical.

    Signed-off-by: Ian Rogers <irogers@google.com>
    Link: https://lore.kernel.org/r/20250604174545.2853620-3-irogers@google.com
    Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Signed-off-by: Anubhav Shelat <ashelat@redhat.com>

Author: AnubhavS1

tools/perf/util/target.c

@@ -94,15 +94,13 @@ enum target_errno target__validate(struct target *target)
 	return ret;
 }
 
-enum target_errno target__parse_uid(struct target *target)
+uid_t parse_uid(const char *str)
 {
 	struct passwd pwd, *result;
 	char buf[1024];
-	const char *str = target->uid_str;
 
-	target->uid = UINT_MAX;
 	if (str == NULL)
-		return TARGET_ERRNO__SUCCESS;
+		return UINT_MAX;
 
 	/* Try user name first */
 	getpwnam_r(str, &pwd, buf, sizeof(buf), &result);
@@ -115,16 +113,22 @@ enum target_errno target__parse_uid(struct target *target)
 		int uid = strtol(str, &endptr, 10);
 
 		if (*endptr != '\0')
-			return TARGET_ERRNO__INVALID_UID;
+			return UINT_MAX;
 
 		getpwuid_r(uid, &pwd, buf, sizeof(buf), &result);
 
 		if (result == NULL)
-			return TARGET_ERRNO__USER_NOT_FOUND;
+			return UINT_MAX;
 	}
 
-	target->uid = result->pw_uid;
-	return TARGET_ERRNO__SUCCESS;
+	return result->pw_uid;
+}
+
+enum target_errno target__parse_uid(struct target *target)
+{
+	target->uid = parse_uid(target->uid_str);
+
+	return target->uid != UINT_MAX ? TARGET_ERRNO__SUCCESS : TARGET_ERRNO__INVALID_UID;
 }
 
 /*
@@ -142,7 +146,6 @@ static const char *target__error_str[] = {
 	"BPF switch overriding UID",
 	"BPF switch overriding THREAD",
 	"Invalid User: %s",
-	"Problems obtaining information for user %s",
 };
 
 int target__strerror(struct target *target, int errnum,
@@ -171,7 +174,6 @@ int target__strerror(struct target *target, int errnum,
 		break;
 
 	case TARGET_ERRNO__INVALID_UID:
-	case TARGET_ERRNO__USER_NOT_FOUND:
 		snprintf(buf, buflen, msg, target->uid_str);
 		break;
 

tools/perf/util/target.h

@@ -48,12 +48,13 @@ enum target_errno {
 
 	/* for target__parse_uid() */
 	TARGET_ERRNO__INVALID_UID,
-	TARGET_ERRNO__USER_NOT_FOUND,
 
 	__TARGET_ERRNO__END,
 };
 
 enum target_errno target__validate(struct target *target);
+
+uid_t parse_uid(const char *str);
 enum target_errno target__parse_uid(struct target *target);
 
 int target__strerror(struct target *target, int errnum, char *buf, size_t buflen);