On 07/04/2017 03:15 PM, PrasannaKumar Muralidharan wrote:
> On 3 July 2017 at 15:33, Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx> wrote:
>> This patch introduces a new sysfs attribute file 'rng_selected'
>> which shows the the rng chosen by userspace.
>>
>> If a rng source is chosen by user via echo some valid string
>> to rng_current there should be a way to signal this choice to
>> userspace. The new attribute file 'rng_selected' shows either
>> the name of the rng chosen or 'none'.
>>
>> Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/char/hw_random/core.c | 22 +++++++++++++++++-----
>> 1 file changed, 17 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
>> index ffd4e36..6a6276a 100644
>> --- a/drivers/char/hw_random/core.c
>> +++ b/drivers/char/hw_random/core.c
>> @@ -28,8 +28,8 @@
>> #define RNG_MODULE_NAME "hw_random"
>>
>> static struct hwrng *current_rng;
>> -/* the current rng has been explicitly chosen by user via sysfs */
>> -static int cur_rng_set_by_user;
>> +/* the rng explicitly selected by user via sysfs */
>> +static struct hwrng *selected_rng;
>> static struct task_struct *hwrng_fill;
>> /* list of registered rngs, sorted decending by quality */
>> static LIST_HEAD(rng_list);
>> @@ -306,7 +306,7 @@ static ssize_t hwrng_attr_current_store(struct device *dev,
>> list_for_each_entry(rng, &rng_list, list) {
>> if (sysfs_streq(rng->name, buf)) {
>> err = 0;
>> - cur_rng_set_by_user = 1;
>> + selected_rng = rng;
>> if (rng != current_rng)
>> err = set_current_rng(rng);
>> break;
>> @@ -355,16 +355,28 @@ static ssize_t hwrng_attr_available_show(struct device *dev,
>> return strlen(buf);
>> }
>>
>> +static ssize_t hwrng_attr_selected_show(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + return snprintf(buf, PAGE_SIZE, "%s\n",
>> + selected_rng ? selected_rng->name : "none");
>> +}
>> +
>> static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
>> hwrng_attr_current_show,
>> hwrng_attr_current_store);
>> static DEVICE_ATTR(rng_available, S_IRUGO,
>> hwrng_attr_available_show,
>> NULL);
>> +static DEVICE_ATTR(rng_selected, S_IRUGO,
>> + hwrng_attr_selected_show,
>> + NULL);
>>
>> static struct attribute *rng_dev_attrs[] = {
>> &dev_attr_rng_current.attr,
>> &dev_attr_rng_available.attr,
>> + &dev_attr_rng_selected.attr,
>> NULL
>> };
>>
>> @@ -448,7 +460,7 @@ int hwrng_register(struct hwrng *rng)
>> old_rng = current_rng;
>> err = 0;
>> if (!old_rng ||
>> - (!cur_rng_set_by_user && rng->quality > old_rng->quality)) {
>> + (!selected_rng && rng->quality > old_rng->quality)) {
>> /*
>> * Set new rng as current as the new rng source
>> * provides better entropy quality and was not
>> @@ -484,7 +496,7 @@ void hwrng_unregister(struct hwrng *rng)
>> list_del(&rng->list);
>> if (current_rng == rng) {
>> drop_current_rng();
>> - cur_rng_set_by_user = 0;
>> + selected_rng = NULL;
>> /* rng_list is sorted by quality, use the best (=first) one */
>> if (!list_empty(&rng_list)) {
>> struct hwrng *new_rng;
>> --
>> 2.7.4
>>
> The current_rng sysfs attribute shows currently selected rng. So this
> new attribute can contain 1 to indicate user's choice, 0 otherwise.
>
> Regards,
> PrasannaKumar
>
Here is an updated version with just showing 0 or 1 in the new sysfs
attribute file:
========== cut ==========
From: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>
Date: Mon, 3 Jul 2017 10:19:22 +0200
Subject: [PATCH 3/3] crypto: hwrng add sysfs attribute to show user selected
rng
This patch introduces a new sysfs attribute file 'rng_selected'
which shows if the current rng has been chosen by userspace.
If a rng source is chosen by user via echo some valid string
to rng_current there should be a way to signal this choice to
userspace. The new attribute file 'rng_selected' shows '1' for
user selecte rng and '0' otherwise.
Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxxxxxxx>
---
drivers/char/hw_random/core.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index ffd4e36..2b4c7f6 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -28,8 +28,8 @@
#define RNG_MODULE_NAME "hw_random"
static struct hwrng *current_rng;
-/* the current rng has been explicitly chosen by user via sysfs */
-static int cur_rng_set_by_user;
+/* the rng explicitly selected by user via sysfs */
+static struct hwrng *selected_rng;
static struct task_struct *hwrng_fill;
/* list of registered rngs, sorted decending by quality */
static LIST_HEAD(rng_list);
@@ -306,7 +306,7 @@ static ssize_t hwrng_attr_current_store(struct device *dev,
list_for_each_entry(rng, &rng_list, list) {
if (sysfs_streq(rng->name, buf)) {
err = 0;
- cur_rng_set_by_user = 1;
+ selected_rng = rng;
if (rng != current_rng)
err = set_current_rng(rng);
break;
@@ -355,16 +355,27 @@ static ssize_t hwrng_attr_available_show(struct device *dev,
return strlen(buf);
}
+static ssize_t hwrng_attr_selected_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return snprintf(buf, PAGE_SIZE, "%d\n", selected_rng ? 1 : 0);
+}
+
static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
hwrng_attr_current_show,
hwrng_attr_current_store);
static DEVICE_ATTR(rng_available, S_IRUGO,
hwrng_attr_available_show,
NULL);
+static DEVICE_ATTR(rng_selected, S_IRUGO,
+ hwrng_attr_selected_show,
+ NULL);
static struct attribute *rng_dev_attrs[] = {
&dev_attr_rng_current.attr,
&dev_attr_rng_available.attr,
+ &dev_attr_rng_selected.attr,
NULL
};
@@ -448,7 +459,7 @@ int hwrng_register(struct hwrng *rng)
old_rng = current_rng;
err = 0;
if (!old_rng ||
- (!cur_rng_set_by_user && rng->quality > old_rng->quality)) {
+ (!selected_rng && rng->quality > old_rng->quality)) {
/*
* Set new rng as current as the new rng source
* provides better entropy quality and was not
@@ -484,7 +495,7 @@ void hwrng_unregister(struct hwrng *rng)
list_del(&rng->list);
if (current_rng == rng) {
drop_current_rng();
- cur_rng_set_by_user = 0;
+ selected_rng = NULL;
/* rng_list is sorted by quality, use the best (=first) one */
if (!list_empty(&rng_list)) {
struct hwrng *new_rng;
--
2.7.4
========== cut ==========
