Re: [PATCH 08/32] tools:iio: save errno first

[Jonathan Cameron <jic23@kernel.org>]

On 31/05/15 13:39, Hartmut Knaack wrote:
> The man-page of errno states, that errno should be saved before doing any
> library call, as that call may have changed the value of errno. So, when
> encountering any error, save errno first.
> This patch affects generic_buffer.c, iio_event_monitor.c and iio_utils.c.
> 
> Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Applied,

Not one I ever thought about, but can easily see why the way it was done
here is a bad idea.  Thanks Hartmut!
> ---
>  tools/iio/generic_buffer.c    |  2 +-
>  tools/iio/iio_event_monitor.c |  6 +++---
>  tools/iio/iio_utils.c         | 14 +++++++-------
>  3 files changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c
> index 51ae3df..d52a55a 100644
> --- a/tools/iio/generic_buffer.c
> +++ b/tools/iio/generic_buffer.c
> @@ -296,8 +296,8 @@ int main(int argc, char **argv)
>  	/* Attempt to open non blocking the access dev */
>  	fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
>  	if (fp == -1) { /* If it isn't there make the node */
> -		printf("Failed to open %s\n", buffer_access);
>  		ret = -errno;
> +		printf("Failed to open %s\n", buffer_access);
>  		goto error_free_buffer_access;
>  	}
>  
> diff --git a/tools/iio/iio_event_monitor.c b/tools/iio/iio_event_monitor.c
> index 427c271..f6fdab4 100644
> --- a/tools/iio/iio_event_monitor.c
> +++ b/tools/iio/iio_event_monitor.c
> @@ -269,8 +269,8 @@ int main(int argc, char **argv)
>  
>  	fd = open(chrdev_name, 0);
>  	if (fd == -1) {
> -		fprintf(stdout, "Failed to open %s\n", chrdev_name);
>  		ret = -errno;
> +		fprintf(stdout, "Failed to open %s\n", chrdev_name);
>  		goto error_free_chrdev_name;
>  	}
>  
> @@ -279,8 +279,8 @@ int main(int argc, char **argv)
>  	close(fd);
>  
>  	if (ret == -1 || event_fd == -1) {
> -		fprintf(stdout, "Failed to retrieve event fd\n");
>  		ret = -errno;
> +		fprintf(stdout, "Failed to retrieve event fd\n");
>  		goto error_free_chrdev_name;
>  	}
>  
> @@ -291,8 +291,8 @@ int main(int argc, char **argv)
>  				printf("nothing available\n");
>  				continue;
>  			} else {
> -				perror("Failed to read event from device");
>  				ret = -errno;
> +				perror("Failed to read event from device");
>  				break;
>  			}
>  		}
> diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
> index 1c0ca2f..f12bc2e 100644
> --- a/tools/iio/iio_utils.c
> +++ b/tools/iio/iio_utils.c
> @@ -129,8 +129,8 @@ int iioutils_get_type(unsigned *is_signed,
>  			}
>  			sysfsfp = fopen(filename, "r");
>  			if (sysfsfp == NULL) {
> -				printf("failed to open %s\n", filename);
>  				ret = -errno;
> +				printf("failed to open %s\n", filename);
>  				goto error_free_filename;
>  			}
>  
> @@ -141,8 +141,8 @@ int iioutils_get_type(unsigned *is_signed,
>  				     bits_used,
>  				     &padint, shift);
>  			if (ret < 0) {
> -				printf("failed to pass scan type description\n");
>  				ret = -errno;
> +				printf("failed to pass scan type description\n");
>  				goto error_close_sysfsfp;
>  			}
>  			*be = (endianchar == 'b');
> @@ -332,8 +332,8 @@ int build_channel_array(const char *device_dir,
>  			}
>  			sysfsfp = fopen(filename, "r");
>  			if (sysfsfp == NULL) {
> -				free(filename);
>  				ret = -errno;
> +				free(filename);
>  				count--;
>  				goto error_cleanup_array;
>  			}
> @@ -505,8 +505,8 @@ int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
>  	sprintf(temp, "%s/%s", basedir, filename);
>  	sysfsfp = fopen(temp, "w");
>  	if (sysfsfp == NULL) {
> -		printf("failed to open %s\n", temp);
>  		ret = -errno;
> +		printf("failed to open %s\n", temp);
>  		goto error_free;
>  	}
>  	fprintf(sysfsfp, "%d", val);
> @@ -514,8 +514,8 @@ int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
>  	if (verify) {
>  		sysfsfp = fopen(temp, "r");
>  		if (sysfsfp == NULL) {
> -			printf("failed to open %s\n", temp);
>  			ret = -errno;
> +			printf("failed to open %s\n", temp);
>  			goto error_free;
>  		}
>  		fscanf(sysfsfp, "%d", &test);
> @@ -556,8 +556,8 @@ int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
>  	sprintf(temp, "%s/%s", basedir, filename);
>  	sysfsfp = fopen(temp, "w");
>  	if (sysfsfp == NULL) {
> -		printf("Could not open %s\n", temp);
>  		ret = -errno;
> +		printf("Could not open %s\n", temp);
>  		goto error_free;
>  	}
>  	fprintf(sysfsfp, "%s", val);
> @@ -565,8 +565,8 @@ int _write_sysfs_string(char *filename, char *basedir, char *val, int verify)
>  	if (verify) {
>  		sysfsfp = fopen(temp, "r");
>  		if (sysfsfp == NULL) {
> -			printf("could not open file to verify\n");
>  			ret = -errno;
> +			printf("could not open file to verify\n");
>  			goto error_free;
>  		}
>  		fscanf(sysfsfp, "%s", temp);
>