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

[Jonathan Cameron <jic23@kernel.org>]

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",