[PATCH BlueZ] plugins: Fix compilation error on autopair

[PATCH BlueZ] plugins: Fix compilation error on autopair

[Anderson Lizardo]

Fix this error caught using gcc 4.6.3:

plugins/autopair.c: In function ‘autopair_init’:
plugins/autopair.c:154:8: error: ignoring return value of ‘fread’,
declared with attribute warn_unused_result [-Werror=unused-result]
---
 plugins/autopair.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/plugins/autopair.c b/plugins/autopair.c
index 5d90f9d..5afc357 100644
--- a/plugins/autopair.c
+++ b/plugins/autopair.c
@@ -146,15 +146,19 @@ static struct btd_adapter_driver autopair_driver = {
 static int autopair_init(void)
 {
 	/* Initialize the random seed from /dev/urandom */
-	unsigned int seed = time(NULL);
+	unsigned int seed;
+	size_t nread = 0;
 	FILE *f;
 
 	f = fopen("/dev/urandom", "rb");
 	if (f != NULL) {
-		fread(&seed, sizeof(seed), 1, f);
+		nread = fread(&seed, sizeof(seed), 1, f);
 		fclose(f);
 	}
 
+	if (f == NULL || nread != 1)
+		seed = time(NULL);
+
 	srand(seed);
 
 	return btd_register_adapter_driver(&autopair_driver);
-- 
1.7.9.5

Re: [PATCH BlueZ] plugins: Fix compilation error on autopair

[Marcel Holtmann]

Hi Anderson,

> Fix this error caught using gcc 4.6.3:
> 
> plugins/autopair.c: In function ‘autopair_init’:
> plugins/autopair.c:154:8: error: ignoring return value of ‘fread’,
> declared with attribute warn_unused_result [-Werror=unused-result]
> ---
> plugins/autopair.c |    8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/plugins/autopair.c b/plugins/autopair.c
> index 5d90f9d..5afc357 100644
> --- a/plugins/autopair.c
> +++ b/plugins/autopair.c
> @@ -146,15 +146,19 @@ static struct btd_adapter_driver autopair_driver = {
> static int autopair_init(void)
> {
> 	/* Initialize the random seed from /dev/urandom */
> -	unsigned int seed = time(NULL);
> +	unsigned int seed;
> +	size_t nread = 0;
> 	FILE *f;
> 
> 	f = fopen("/dev/urandom", "rb");
> 	if (f != NULL) {
> -		fread(&seed, sizeof(seed), 1, f);
> +		nread = fread(&seed, sizeof(seed), 1, f);
> 		fclose(f);
> 	}
> 
> +	if (f == NULL || nread != 1)
> +		seed = time(NULL);
> +
> 	srand(seed);

lets redo this in actually readable code ;)

Checking f twice is not acceptable. And I still wonder why fopen() is here preferred over open().

Regards

Marcel

Re: [PATCH BlueZ] plugins: Fix compilation error on autopair

[Anderson Lizardo]

Hi Marcel,

On Thu, May 16, 2013 at 10:07 AM, Marcel Holtmann <marcel@holtmann.org> wrote:
>>       f = fopen("/dev/urandom", "rb");
>>       if (f != NULL) {
>> -             fread(&seed, sizeof(seed), 1, f);
>> +             nread = fread(&seed, sizeof(seed), 1, f);
>>               fclose(f);
>>       }
>>
>> +     if (f == NULL || nread != 1)
>> +             seed = time(NULL);
>> +
>>       srand(seed);
>
> lets redo this in actually readable code ;)
>
> Checking f twice is not acceptable. And I still wonder why fopen() is here preferred over open().

I just sent another version that uses open()/read() instead.
Compilation tested only.

Regards,
-- 
Anderson Lizardo
Instituto Nokia de Tecnologia - INdT
Manaus - Brazil