linux-kernel - [PATCH v4] cpupower:Fix resource leaks in sysfs_get

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Date:   Tue, 18 Apr 2023 09:30:56 +0800
From:   Hao Zeng <zenghao@...inos.cn>
To:     skhan@...uxfoundation.org
Cc:     trenn@...e.com, shuah@...nel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, zenghao@...inos.cn
Subject: [PATCH v4] cpupower:Fix resource leaks in sysfs_get_enabled()

The sysfs_get_enabled() opened file processor not closed,
may cause a file handle leak.
Putting error handling and resource cleanup code together
makes the code easy to maintain and read.
Removed the unnecessary else if branch from the original
function, as it should return an error in cases other than '0'.

Signed-off-by: Hao Zeng <zenghao@...inos.cn>
Suggested-by: Shuah Khan <skhan@...uxfoundation.org>
---
 tools/power/cpupower/lib/powercap.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
index 0ce29ee4c2e4..a7a59c6bacda 100644
--- a/tools/power/cpupower/lib/powercap.c
+++ b/tools/power/cpupower/lib/powercap.c
@@ -40,25 +40,34 @@ static int sysfs_get_enabled(char *path, int *mode)
 {
 	int fd;
 	char yes_no;
+	int ret = 0;
 
 	*mode = 0;
 
 	fd = open(path, O_RDONLY);
-	if (fd == -1)
-		return -1;
+	if (fd == -1) {
+		ret = -1;
+		goto out;
+	}
 
 	if (read(fd, &yes_no, 1) != 1) {
-		close(fd);
-		return -1;
+		ret = -1;
+		goto out_close;
 	}
 
 	if (yes_no == '1') {
 		*mode = 1;
-		return 0;
+		goto out_close;
 	} else if (yes_no == '0') {
-		return 0;
+		goto out_close;
+	} else {
+		ret = -1;
+		goto out_close;
 	}
-	return -1;
+out_close:
+	close(fd);
+out:
+	return ret;
 }
 
 int powercap_get_enabled(int *mode)
-- 
2.37.2