[PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

[PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

[Hao Zeng]

When the read return value is equal to 1, a file handle leak will occur

Signed-off-by: Hao Zeng <zenghao@kylinos.cn>
Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
---
 tools/power/cpupower/lib/powercap.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
index 0ce29ee4c2e4..02ec5b0bff6b 100644
--- a/tools/power/cpupower/lib/powercap.c
+++ b/tools/power/cpupower/lib/powercap.c
@@ -40,7 +40,7 @@ static int sysfs_get_enabled(char *path, int *mode)
 {
 	int fd;
 	char yes_no;
-
+	int ret = 0;
 	*mode = 0;
 
 	fd = open(path, O_RDONLY);
@@ -48,17 +48,18 @@ static int sysfs_get_enabled(char *path, int *mode)
 		return -1;
 
 	if (read(fd, &yes_no, 1) != 1) {
-		close(fd);
-		return -1;
+		ret = -1;
+		goto err;
 	}
 
-	if (yes_no == '1') {
-		*mode = 1;
-		return 0;
-	} else if (yes_no == '0') {
-		return 0;
+	if (yes_no != '1' || yes_no != '0') {
+		ret = -1;
+		goto err;
 	}
-	return -1;
+	*mode = yes_no - '0';
+err:
+	close(fd);
+	return ret;
 }
 
 int powercap_get_enabled(int *mode)
-- 
2.37.2


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Re: [PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

[Shuah Khan]

On 4/13/23 21:08, Hao Zeng wrote:
> When the read return value is equal to 1, a file handle leak will occur
> 

Would like a bit more information on how the error paths are
redone, since memory leak isn't the only one that is fixed.

> Signed-off-by: Hao Zeng <zenghao@kylinos.cn>
> Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
> ---
>   tools/power/cpupower/lib/powercap.c | 19 ++++++++++---------
>   1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
> index 0ce29ee4c2e4..02ec5b0bff6b 100644
> --- a/tools/power/cpupower/lib/powercap.c
> +++ b/tools/power/cpupower/lib/powercap.c
> @@ -40,7 +40,7 @@ static int sysfs_get_enabled(char *path, int *mode)
>   {
>   	int fd;
>   	char yes_no;
> -
> +	int ret = 0;
>   	*mode = 0;
>   
>   	fd = open(path, O_RDONLY);
> @@ -48,17 +48,18 @@ static int sysfs_get_enabled(char *path, int *mode)
>   		return -1;
>   
>   	if (read(fd, &yes_no, 1) != 1) {
> -		close(fd);
> -		return -1;
> +		ret = -1;
> +		goto err;
>   	}
>   
> -	if (yes_no == '1') {
> -		*mode = 1;
> -		return 0;
> -	} else if (yes_no == '0') {
> -		return 0;
> +	if (yes_no != '1' || yes_no != '0') {
> +		ret = -1;
> +		goto err;
>   	}
> -	return -1;
> +	*mode = yes_no - '0';

I am not seeing much value in changing the above paths.
Leave them unchanged.

> +err:
> +	close(fd);
> +	return ret;
>   }
>   
>   int powercap_get_enabled(int *mode)

thanks,
-- Shuah

Re: [PATCH v2] cpupower:Fix resource leaks in sysfs_get_enabled()

[Hao Zeng]

Hi Shuah , Thanks very much for your review!
I tried to understand what you said as best I could and provided V3.
I look forward to your review again, it will help me a lot!

Best regards
-- Hao

On Fri, 2023-04-14 at 10:41 -0600, Shuah Khan wrote:
> On 4/13/23 21:08, Hao Zeng wrote:
> > When the read return value is equal to 1, a file handle leak will
> > occur
> > 
> 
> Would like a bit more information on how the error paths are
> redone, since memory leak isn't the only one that is fixed.
> 
> > Signed-off-by: Hao Zeng <zenghao@kylinos.cn>
> > Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
> > ---
> >   tools/power/cpupower/lib/powercap.c | 19 ++++++++++---------
> >   1 file changed, 10 insertions(+), 9 deletions(-)
> > 
> > diff --git a/tools/power/cpupower/lib/powercap.c
> > b/tools/power/cpupower/lib/powercap.c
> > index 0ce29ee4c2e4..02ec5b0bff6b 100644
> > --- a/tools/power/cpupower/lib/powercap.c
> > +++ b/tools/power/cpupower/lib/powercap.c
> > @@ -40,7 +40,7 @@ static int sysfs_get_enabled(char *path, int
> > *mode)
> >   {
> >         int fd;
> >         char yes_no;
> > -
> > +       int ret = 0;
> >         *mode = 0;
> >   
> >         fd = open(path, O_RDONLY);
> > @@ -48,17 +48,18 @@ static int sysfs_get_enabled(char *path, int
> > *mode)
> >                 return -1;
> >   
> >         if (read(fd, &yes_no, 1) != 1) {
> > -               close(fd);
> > -               return -1;
> > +               ret = -1;
> > +               goto err;
> >         }
> >   
> > -       if (yes_no == '1') {
> > -               *mode = 1;
> > -               return 0;
> > -       } else if (yes_no == '0') {
> > -               return 0;
> > +       if (yes_no != '1' || yes_no != '0') {
> > +               ret = -1;
> > +               goto err;
> >         }
> > -       return -1;
> > +       *mode = yes_no - '0';
> 
> I am not seeing much value in changing the above paths.
> Leave them unchanged.
> 
> > +err:
> > +       close(fd);
> > +       return ret;
> >   }
> >   
> >   int powercap_get_enabled(int *mode)
> 
> thanks,
> -- Shuah