[v1] tools/iio/iio_utils:fix memory leak

[PATCH] tools/iio/iio_utils:fix memory leak

Posted by Yulong Zhang 2 years, 8 months ago

1.fopen sysfsfp without fclose
2.asprintf filename without free

Signed-off-by: Yulong Zhang <yulong.zhang@metoak.net>
---
 tools/iio/iio_utils.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
index 8d35893b2..38e9352e5 100644
--- a/tools/iio/iio_utils.c
+++ b/tools/iio/iio_utils.c
@@ -264,6 +264,8 @@ int iioutils_get_param_float(float *output, const char *param_name,
 			if (fscanf(sysfsfp, "%f", output) != 1)
 				ret = errno ? -errno : -ENODATA;
 
+			fclose(sysfsfp);
+
 			break;
 		}
 error_free_filename:
@@ -444,6 +446,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				count--;
 				goto error_cleanup_array;
 			}
+			free(filename);
 
 			ret = asprintf(&filename,
 				       "%s/%s_index",
-- 
2.25.1

Re: [PATCH] tools/iio/iio_utils:fix memory leak

Posted by Jonathan Cameron 2 years, 8 months ago

On Thu, 12 Jan 2023 19:01:22 +0800
Yulong Zhang <yulong.zhang@metoak.net> wrote:

> 1.fopen sysfsfp without fclose
> 2.asprintf filename without free
> 
> Signed-off-by: Yulong Zhang <yulong.zhang@metoak.net>
Good spot.  One suggestion below on how to tidy up the code
whilst fixing this.

> ---
>  tools/iio/iio_utils.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
> index 8d35893b2..38e9352e5 100644
> --- a/tools/iio/iio_utils.c
> +++ b/tools/iio/iio_utils.c
> @@ -264,6 +264,8 @@ int iioutils_get_param_float(float *output, const char *param_name,
>  			if (fscanf(sysfsfp, "%f", output) != 1)
>  				ret = errno ? -errno : -ENODATA;
>  
> +			fclose(sysfsfp);
> +
>  			break;
>  		}
>  error_free_filename:
> @@ -444,6 +446,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				count--;
>  				goto error_cleanup_array;
>  			}
> +			free(filename);

Instead of doing it here, why not move the free as early as possible (and hence
drop the need to do it in most of the error paths.
			sysfsfp = fopen(filename, "r");
		+	free(filename);
			if (!sysfsfp) {
				ret = -errno;
		-		free(filename)
... and the other cases that follow.

The same could be done for the case below, at the minor cost of not
having the filename for the print statement (which I think would be fine).

>  
>  			ret = asprintf(&filename,
>  				       "%s/%s_index",

[PATCH v2] tools/iio/iio_utils:fix memory leak

Posted by Yulong Zhang 2 years, 8 months ago

1. fopen sysfs without fclose.
2. asprintf filename without free.
3. if asprintf return error,do not need to free the buffer.

Signed-off-by: Yulong Zhang <yulong.zhang@metoak.net>
---
Yes, you are right. Thanks you for the advice.
I found another problem, when asprintf return error, still free the
buffer.This is not correct,I've removed it.

> sysfsfp = fopen(filename, "r");
> if (!sysfsfp) {
>       ret = -errno;
>       fprintf(stderr, "failed to open %s\n",
>               filename);
>       free(filename);
>       goto error_cleanup_array;
> }
> free(filename);
Because in if statement still use filename,so I can't free filename
before it.And I am not sure it can be removed,so I free filename after if
statement.

 tools/iio/iio_utils.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
index 8d35893b2fa8..abec4331701c 100644
--- a/tools/iio/iio_utils.c
+++ b/tools/iio/iio_utils.c
@@ -264,6 +264,7 @@ int iioutils_get_param_float(float *output, const char *param_name,
 			if (fscanf(sysfsfp, "%f", output) != 1)
 				ret = errno ? -errno : -ENODATA;
 
+			fclose(sysfsfp);
 			break;
 		}
 error_free_filename:
@@ -350,6 +351,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				free(filename);
 				goto error_close_dir;
 			}
+			free(filename);
 
 			errno = 0;
 			if (fscanf(sysfsfp, "%i", &ret) != 1) {
@@ -357,7 +359,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				if (fclose(sysfsfp))
 					perror("build_channel_array(): Failed to close file");
 
-				free(filename);
 				goto error_close_dir;
 			}
 			if (ret == 1)
@@ -365,11 +366,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				goto error_close_dir;
 			}
 
-			free(filename);
 		}
 
 	*ci_array = malloc(sizeof(**ci_array) * (*counter));
@@ -395,9 +394,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			if (!sysfsfp) {
 				ret = -errno;
-				free(filename);
 				count--;
 				goto error_cleanup_array;
 			}
@@ -405,20 +404,17 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			errno = 0;
 			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
 				ret = errno ? -errno : -ENODATA;
-				free(filename);
 				count--;
 				goto error_cleanup_array;
 			}
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				count--;
 				goto error_cleanup_array;
 			}
 
 			if (!current_enabled) {
-				free(filename);
 				count--;
 				continue;
 			}
@@ -429,7 +425,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 						strlen(ent->d_name) -
 						strlen("_en"));
 			if (!current->name) {
-				free(filename);
 				ret = -ENOMEM;
 				count--;
 				goto error_cleanup_array;
@@ -439,7 +434,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			ret = iioutils_break_up_name(current->name,
 						     &current->generic_name);
 			if (ret) {
-				free(filename);
 				free(current->name);
 				count--;
 				goto error_cleanup_array;
@@ -450,7 +444,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				       scan_el_dir,
 				       current->name);
 			if (ret < 0) {
-				free(filename);
 				ret = -ENOMEM;
 				goto error_cleanup_array;
 			}
@@ -463,6 +456,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				free(filename);
 				goto error_cleanup_array;
 			}
+			free(filename);
 
 			errno = 0;
 			if (fscanf(sysfsfp, "%u", &current->index) != 1) {
@@ -470,17 +464,14 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				if (fclose(sysfsfp))
 					perror("build_channel_array(): Failed to close file");
 
-				free(filename);
 				goto error_cleanup_array;
 			}
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				goto error_cleanup_array;
 			}
 
-			free(filename);
 			/* Find the scale */
 			ret = iioutils_get_param_float(&current->scale,
 						       "scale",
-- 
2.25.1

Re: [PATCH v2] tools/iio/iio_utils:fix memory leak

Posted by Jonathan Cameron 2 years, 8 months ago

On Mon, 16 Jan 2023 11:30:07 +0800
Yulong Zhang <yulong.zhang@metoak.net> wrote:

> 1. fopen sysfs without fclose.
> 2. asprintf filename without free.
> 3. if asprintf return error,do not need to free the buffer.
> 
> Signed-off-by: Yulong Zhang <yulong.zhang@metoak.net>
> ---
> Yes, you are right. Thanks you for the advice.
> I found another problem, when asprintf return error, still free the
> buffer.This is not correct,I've removed it.
> 
> > sysfsfp = fopen(filename, "r");
> > if (!sysfsfp) {
> >       ret = -errno;
> >       fprintf(stderr, "failed to open %s\n",
> >               filename);
> >       free(filename);
> >       goto error_cleanup_array;
> > }
> > free(filename);  
> Because in if statement still use filename,so I can't free filename
> before it.And I am not sure it can be removed,so I free filename after if
> statement.

Agreed.  My suggestion is drop that error print to simplify the code.
It isn't particularly important to know the full filename that we failed
to open so I think dropping it is a reasonable thing to do.

If you really care about the message then
fprintf(stderr, "failed to open %s/%s_index\n", scan_el_dir, current->name);
will work.


> 
>  tools/iio/iio_utils.c | 17 ++++-------------
>  1 file changed, 4 insertions(+), 13 deletions(-)
> 
> diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
> index 8d35893b2fa8..abec4331701c 100644
> --- a/tools/iio/iio_utils.c
> +++ b/tools/iio/iio_utils.c
> @@ -264,6 +264,7 @@ int iioutils_get_param_float(float *output, const char *param_name,
>  			if (fscanf(sysfsfp, "%f", output) != 1)
>  				ret = errno ? -errno : -ENODATA;
>  
> +			fclose(sysfsfp);
>  			break;
>  		}
>  error_free_filename:
> @@ -350,6 +351,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				free(filename);
>  				goto error_close_dir;
>  			}
> +			free(filename);
>  
>  			errno = 0;
>  			if (fscanf(sysfsfp, "%i", &ret) != 1) {
> @@ -357,7 +359,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				if (fclose(sysfsfp))
>  					perror("build_channel_array(): Failed to close file");
>  
> -				free(filename);
>  				goto error_close_dir;
>  			}
>  			if (ret == 1)
> @@ -365,11 +366,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  
>  			if (fclose(sysfsfp)) {
>  				ret = -errno;
> -				free(filename);
>  				goto error_close_dir;
>  			}
>  
> -			free(filename);
>  		}
>  
>  	*ci_array = malloc(sizeof(**ci_array) * (*counter));
> @@ -395,9 +394,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			}
>  
>  			sysfsfp = fopen(filename, "r");
> +			free(filename);
>  			if (!sysfsfp) {
>  				ret = -errno;
> -				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
> @@ -405,20 +404,17 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			errno = 0;
>  			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
>  				ret = errno ? -errno : -ENODATA;
> -				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
>  
>  			if (fclose(sysfsfp)) {
>  				ret = -errno;
> -				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
>  
>  			if (!current_enabled) {
> -				free(filename);
>  				count--;
>  				continue;
>  			}
> @@ -429,7 +425,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  						strlen(ent->d_name) -
>  						strlen("_en"));
>  			if (!current->name) {
> -				free(filename);
>  				ret = -ENOMEM;
>  				count--;
>  				goto error_cleanup_array;
> @@ -439,7 +434,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			ret = iioutils_break_up_name(current->name,
>  						     &current->generic_name);
>  			if (ret) {
> -				free(filename);
>  				free(current->name);
>  				count--;
>  				goto error_cleanup_array;
> @@ -450,7 +444,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				       scan_el_dir,
>  				       current->name);
>  			if (ret < 0) {
> -				free(filename);
>  				ret = -ENOMEM;
>  				goto error_cleanup_array;
>  			}
> @@ -463,6 +456,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				free(filename);
>  				goto error_cleanup_array;
>  			}
> +			free(filename);
>  
>  			errno = 0;
>  			if (fscanf(sysfsfp, "%u", &current->index) != 1) {
> @@ -470,17 +464,14 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				if (fclose(sysfsfp))
>  					perror("build_channel_array(): Failed to close file");
>  
> -				free(filename);
>  				goto error_cleanup_array;
>  			}
>  
>  			if (fclose(sysfsfp)) {
>  				ret = -errno;
> -				free(filename);
>  				goto error_cleanup_array;
>  			}
>  
> -			free(filename);
>  			/* Find the scale */
>  			ret = iioutils_get_param_float(&current->scale,
>  						       "scale",

[PATCH v3] tools/iio/iio_utils:fix memory leak

Posted by Yulong Zhang 2 years, 8 months ago

1. fopen sysfs without fclose.
2. asprintf filename without free.
3. if asprintf return error,do not need to free the buffer.

Signed-off-by: Yulong Zhang <yulong.zhang@metoak.net>
---
 tools/iio/iio_utils.c | 23 ++++++-----------------
 1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
index 8d35893b2fa8..6a00a6eecaef 100644
--- a/tools/iio/iio_utils.c
+++ b/tools/iio/iio_utils.c
@@ -264,6 +264,7 @@ int iioutils_get_param_float(float *output, const char *param_name,
 			if (fscanf(sysfsfp, "%f", output) != 1)
 				ret = errno ? -errno : -ENODATA;
 
+			fclose(sysfsfp);
 			break;
 		}
 error_free_filename:
@@ -345,9 +346,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			if (!sysfsfp) {
 				ret = -errno;
-				free(filename);
 				goto error_close_dir;
 			}
 
@@ -357,7 +358,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				if (fclose(sysfsfp))
 					perror("build_channel_array(): Failed to close file");
 
-				free(filename);
 				goto error_close_dir;
 			}
 			if (ret == 1)
@@ -365,11 +365,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				goto error_close_dir;
 			}
 
-			free(filename);
 		}
 
 	*ci_array = malloc(sizeof(**ci_array) * (*counter));
@@ -395,9 +393,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			if (!sysfsfp) {
 				ret = -errno;
-				free(filename);
 				count--;
 				goto error_cleanup_array;
 			}
@@ -405,20 +403,17 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			errno = 0;
 			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
 				ret = errno ? -errno : -ENODATA;
-				free(filename);
 				count--;
 				goto error_cleanup_array;
 			}
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				count--;
 				goto error_cleanup_array;
 			}
 
 			if (!current_enabled) {
-				free(filename);
 				count--;
 				continue;
 			}
@@ -429,7 +424,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 						strlen(ent->d_name) -
 						strlen("_en"));
 			if (!current->name) {
-				free(filename);
 				ret = -ENOMEM;
 				count--;
 				goto error_cleanup_array;
@@ -439,7 +433,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			ret = iioutils_break_up_name(current->name,
 						     &current->generic_name);
 			if (ret) {
-				free(filename);
 				free(current->name);
 				count--;
 				goto error_cleanup_array;
@@ -450,17 +443,16 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				       scan_el_dir,
 				       current->name);
 			if (ret < 0) {
-				free(filename);
 				ret = -ENOMEM;
 				goto error_cleanup_array;
 			}
 
 			sysfsfp = fopen(filename, "r");
+			free(filename);
 			if (!sysfsfp) {
 				ret = -errno;
-				fprintf(stderr, "failed to open %s\n",
-					filename);
-				free(filename);
+				fprintf(stderr, "failed to open %s/%s_index\n",
+					scan_el_dir, current->name);
 				goto error_cleanup_array;
 			}
 
@@ -470,17 +462,14 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 				if (fclose(sysfsfp))
 					perror("build_channel_array(): Failed to close file");
 
-				free(filename);
 				goto error_cleanup_array;
 			}
 
 			if (fclose(sysfsfp)) {
 				ret = -errno;
-				free(filename);
 				goto error_cleanup_array;
 			}
 
-			free(filename);
 			/* Find the scale */
 			ret = iioutils_get_param_float(&current->scale,
 						       "scale",
-- 
2.25.1

Re: [PATCH v3] tools/iio/iio_utils:fix memory leak

Posted by Jonathan Cameron 2 years, 7 months ago

On Tue, 17 Jan 2023 10:51:47 +0800
Yulong Zhang <yulong.zhang@metoak.net> wrote:

> 1. fopen sysfs without fclose.
> 2. asprintf filename without free.
> 3. if asprintf return error,do not need to free the buffer.
> 
> Signed-off-by: Yulong Zhang <yulong.zhang@metoak.net>
I'm not that worried about rushing in a memory leak fix for the example
code, so I've queued this up for the next merge window.

Thanks,

Jonathan

> ---
>  tools/iio/iio_utils.c | 23 ++++++-----------------
>  1 file changed, 6 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
> index 8d35893b2fa8..6a00a6eecaef 100644
> --- a/tools/iio/iio_utils.c
> +++ b/tools/iio/iio_utils.c
> @@ -264,6 +264,7 @@ int iioutils_get_param_float(float *output, const char *param_name,
>  			if (fscanf(sysfsfp, "%f", output) != 1)
>  				ret = errno ? -errno : -ENODATA;
>  
> +			fclose(sysfsfp);
>  			break;
>  		}
>  error_free_filename:
> @@ -345,9 +346,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			}
>  
>  			sysfsfp = fopen(filename, "r");
> +			free(filename);
>  			if (!sysfsfp) {
>  				ret = -errno;
> -				free(filename);
>  				goto error_close_dir;
>  			}
>  
> @@ -357,7 +358,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				if (fclose(sysfsfp))
>  					perror("build_channel_array(): Failed to close file");
>  
> -				free(filename);
>  				goto error_close_dir;
>  			}
>  			if (ret == 1)
> @@ -365,11 +365,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  
>  			if (fclose(sysfsfp)) {
>  				ret = -errno;
> -				free(filename);
>  				goto error_close_dir;
>  			}
>  
> -			free(filename);
>  		}
>  
>  	*ci_array = malloc(sizeof(**ci_array) * (*counter));
> @@ -395,9 +393,9 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			}
>  
>  			sysfsfp = fopen(filename, "r");
> +			free(filename);
>  			if (!sysfsfp) {
>  				ret = -errno;
> -				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
> @@ -405,20 +403,17 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			errno = 0;
>  			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
>  				ret = errno ? -errno : -ENODATA;
> -				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
>  
>  			if (fclose(sysfsfp)) {
>  				ret = -errno;
> -				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
>  
>  			if (!current_enabled) {
> -				free(filename);
>  				count--;
>  				continue;
>  			}
> @@ -429,7 +424,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  						strlen(ent->d_name) -
>  						strlen("_en"));
>  			if (!current->name) {
> -				free(filename);
>  				ret = -ENOMEM;
>  				count--;
>  				goto error_cleanup_array;
> @@ -439,7 +433,6 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  			ret = iioutils_break_up_name(current->name,
>  						     &current->generic_name);
>  			if (ret) {
> -				free(filename);
>  				free(current->name);
>  				count--;
>  				goto error_cleanup_array;
> @@ -450,17 +443,16 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				       scan_el_dir,
>  				       current->name);
>  			if (ret < 0) {
> -				free(filename);
>  				ret = -ENOMEM;
>  				goto error_cleanup_array;
>  			}
>  
>  			sysfsfp = fopen(filename, "r");
> +			free(filename);
>  			if (!sysfsfp) {
>  				ret = -errno;
> -				fprintf(stderr, "failed to open %s\n",
> -					filename);
> -				free(filename);
> +				fprintf(stderr, "failed to open %s/%s_index\n",
> +					scan_el_dir, current->name);
>  				goto error_cleanup_array;
>  			}
>  
> @@ -470,17 +462,14 @@ int build_channel_array(const char *device_dir, int buffer_idx,
>  				if (fclose(sysfsfp))
>  					perror("build_channel_array(): Failed to close file");
>  
> -				free(filename);
>  				goto error_cleanup_array;
>  			}
>  
>  			if (fclose(sysfsfp)) {
>  				ret = -errno;
> -				free(filename);
>  				goto error_cleanup_array;
>  			}
>  
> -			free(filename);
>  			/* Find the scale */
>  			ret = iioutils_get_param_float(&current->scale,
>  						       "scale",