[linux-nfc] [PATCH] tag: Implement readout of tag UID via DBus interface

[linux-nfc] [PATCH] tag: Implement readout of tag UID via DBus interface

[Schrempf Frieder]

[-- Attachment #1: Type: text/plain, Size: 3382 bytes --]

From: Frieder Schrempf <frieder.schrempf@kontron.de>

This adds a 'Uid' property to the DBus interface for tags, which
returns the UID of the tag as byte array.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 3 deletions(-)

diff --git a/src/tag.c b/src/tag.c
index 9eba4ee..2039e48 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -53,6 +53,7 @@ struct near_tag {
 	uint8_t nfcid_len;
 
 	uint8_t iso15693_dsfid;
+	uint8_t iso15693_uid_len;
 	uint8_t iso15693_uid[NFC_MAX_ISO15693_UID_LEN];
 
 	size_t data_length;
@@ -168,6 +169,29 @@ static const char *type_string(struct near_tag *tag)
 	return type;
 }
 
+static const uint8_t uid_array(struct near_tag *tag, uint8_t **uid)
+{
+	if (tag->nfcid_len) {
+		DBG("NFCID: ");
+		for(int i = 0; i < tag->nfcid_len; i++)
+			DBG("%x", tag->nfcid[i]);
+
+		*uid = tag->nfcid;
+
+		return tag->nfcid_len;
+	} else if (tag->iso15693_uid_len) {
+		DBG("ISO-UID: ");
+		for(int i = 0; i < tag->iso15693_uid_len; i++)
+			DBG("%x", tag->iso15693_uid[i]);
+
+		*uid = tag->iso15693_uid;
+
+		return tag->iso15693_uid_len;
+	}
+
+	return 0;
+}
+
 static const char *protocol_string(struct near_tag *tag)
 {
 	const char *protocol;
@@ -219,6 +243,30 @@ static gboolean property_get_type(const GDBusPropertyTable *property,
 	return TRUE;
 }
 
+static gboolean property_get_uid(const GDBusPropertyTable *property,
+					DBusMessageIter *iter, void *user_data)
+{
+	struct near_tag *tag = user_data;
+	DBusMessageIter entry;
+	uint8_t *uid;
+	uint8_t len;
+
+	len = uid_array(tag, &uid);
+	if (!uid || !len)
+		return FALSE;
+
+	dbus_message_iter_open_container(iter, DBUS_TYPE_ARRAY,
+					 "{y}", &entry);
+
+	for (int i = 0; i < len; i++)
+		dbus_message_iter_append_basic(&entry, DBUS_TYPE_BYTE,
+					       (void *)&uid[i]);
+
+	dbus_message_iter_close_container(iter, &entry);
+
+	return TRUE;
+}
+
 static gboolean property_get_protocol(const GDBusPropertyTable *property,
 					DBusMessageIter *iter, void *user_data)
 {
@@ -526,6 +574,7 @@ static const GDBusPropertyTable tag_properties[] = {
 	{ "Protocol", "s", property_get_protocol },
 	{ "ReadOnly", "b", property_get_readonly },
 	{ "Adapter", "o", property_get_adapter },
+	{ "Uid", "ay", property_get_uid },
 
 	{ }
 };
@@ -671,8 +720,10 @@ static int tag_initialize(struct near_tag *tag,
 	if (nfcid_len && nfcid_len <= NFC_MAX_NFCID1_LEN) {
 		tag->nfcid_len = nfcid_len;
 		memcpy(tag->nfcid, nfcid, nfcid_len);
-	} else if (iso15693_uid_len) {
+	} else if (iso15693_uid_len &&
+		   iso15693_uid_len <= NFC_MAX_ISO15693_UID_LEN) {
 		tag->iso15693_dsfid = iso15693_dsfid;
+		tag->iso15693_uid_len = iso15693_uid_len;
 		memcpy(tag->iso15693_uid, iso15693_uid, iso15693_uid_len);
 	}
 
@@ -837,11 +888,11 @@ uint8_t *near_tag_get_iso15693_uid(uint32_t adapter_idx, uint32_t target_idx)
 	if (!tag)
 		goto fail;
 
-	iso15693_uid = g_try_malloc0(NFC_MAX_ISO15693_UID_LEN);
+	iso15693_uid = g_try_malloc0(tag->iso15693_uid_len);
 	if (!iso15693_uid)
 		goto fail;
 
-	memcpy(iso15693_uid, tag->iso15693_uid, NFC_MAX_ISO15693_UID_LEN);
+	memcpy(iso15693_uid, tag->iso15693_uid, tag->iso15693_uid_len);
 
 	return iso15693_uid;
 
-- 
2.25.1

[PATCH] tag: Implement readout of tag UID via DBus interface

[Schrempf Frieder]

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From: Frieder Schrempf <frieder.schrempf@kontron.de>

This adds a 'Uid' property to the DBus interface for tags, which
returns the UID of the tag as byte array.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
---
 src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 3 deletions(-)

diff --git a/src/tag.c b/src/tag.c
index 9eba4ee..2039e48 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -53,6 +53,7 @@ struct near_tag {
 	uint8_t nfcid_len;
 
 	uint8_t iso15693_dsfid;
+	uint8_t iso15693_uid_len;
 	uint8_t iso15693_uid[NFC_MAX_ISO15693_UID_LEN];
 
 	size_t data_length;
@@ -168,6 +169,29 @@ static const char *type_string(struct near_tag *tag)
 	return type;
 }
 
+static const uint8_t uid_array(struct near_tag *tag, uint8_t **uid)
+{
+	if (tag->nfcid_len) {
+		DBG("NFCID: ");
+		for(int i = 0; i < tag->nfcid_len; i++)
+			DBG("%x", tag->nfcid[i]);
+
+		*uid = tag->nfcid;
+
+		return tag->nfcid_len;
+	} else if (tag->iso15693_uid_len) {
+		DBG("ISO-UID: ");
+		for(int i = 0; i < tag->iso15693_uid_len; i++)
+			DBG("%x", tag->iso15693_uid[i]);
+
+		*uid = tag->iso15693_uid;
+
+		return tag->iso15693_uid_len;
+	}
+
+	return 0;
+}
+
 static const char *protocol_string(struct near_tag *tag)
 {
 	const char *protocol;
@@ -219,6 +243,30 @@ static gboolean property_get_type(const GDBusPropertyTable *property,
 	return TRUE;
 }
 
+static gboolean property_get_uid(const GDBusPropertyTable *property,
+					DBusMessageIter *iter, void *user_data)
+{
+	struct near_tag *tag = user_data;
+	DBusMessageIter entry;
+	uint8_t *uid;
+	uint8_t len;
+
+	len = uid_array(tag, &uid);
+	if (!uid || !len)
+		return FALSE;
+
+	dbus_message_iter_open_container(iter, DBUS_TYPE_ARRAY,
+					 "{y}", &entry);
+
+	for (int i = 0; i < len; i++)
+		dbus_message_iter_append_basic(&entry, DBUS_TYPE_BYTE,
+					       (void *)&uid[i]);
+
+	dbus_message_iter_close_container(iter, &entry);
+
+	return TRUE;
+}
+
 static gboolean property_get_protocol(const GDBusPropertyTable *property,
 					DBusMessageIter *iter, void *user_data)
 {
@@ -526,6 +574,7 @@ static const GDBusPropertyTable tag_properties[] = {
 	{ "Protocol", "s", property_get_protocol },
 	{ "ReadOnly", "b", property_get_readonly },
 	{ "Adapter", "o", property_get_adapter },
+	{ "Uid", "ay", property_get_uid },
 
 	{ }
 };
@@ -671,8 +720,10 @@ static int tag_initialize(struct near_tag *tag,
 	if (nfcid_len && nfcid_len <= NFC_MAX_NFCID1_LEN) {
 		tag->nfcid_len = nfcid_len;
 		memcpy(tag->nfcid, nfcid, nfcid_len);
-	} else if (iso15693_uid_len) {
+	} else if (iso15693_uid_len &&
+		   iso15693_uid_len <= NFC_MAX_ISO15693_UID_LEN) {
 		tag->iso15693_dsfid = iso15693_dsfid;
+		tag->iso15693_uid_len = iso15693_uid_len;
 		memcpy(tag->iso15693_uid, iso15693_uid, iso15693_uid_len);
 	}
 
@@ -837,11 +888,11 @@ uint8_t *near_tag_get_iso15693_uid(uint32_t adapter_idx, uint32_t target_idx)
 	if (!tag)
 		goto fail;
 
-	iso15693_uid = g_try_malloc0(NFC_MAX_ISO15693_UID_LEN);
+	iso15693_uid = g_try_malloc0(tag->iso15693_uid_len);
 	if (!iso15693_uid)
 		goto fail;
 
-	memcpy(iso15693_uid, tag->iso15693_uid, NFC_MAX_ISO15693_UID_LEN);
+	memcpy(iso15693_uid, tag->iso15693_uid, tag->iso15693_uid_len);
 
 	return iso15693_uid;
 
-- 
2.25.1

[linux-nfc] Re: [PATCH] tag: Implement readout of tag UID via DBus interface

[Mark Greer]

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On Thu, Mar 11, 2021@09:50:20AM +0100, Schrempf Frieder wrote:
> From: Frieder Schrempf <frieder.schrempf@kontron.de>

Hi Frieder.

I am supposed to be taking over neard maintenance but I have been
completely derelict in my duties.  I need to refresh my brain's
cache and look@your patch in more detail.  In the meantime,
I have a few minor comments below.

> 
> This adds a 'Uid' property to the DBus interface for tags, which
> returns the UID of the tag as byte array.

Please add more high-level information to this commit description.
For example, what problem does it solve and how does it solve it?
Something that we can look back@in 5 years and be satisfied that
it solved a problem, that it solved the problem in reasonable way,
and that it was a change worth incorporating.

> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
> ---
>  src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 54 insertions(+), 3 deletions(-)
> 
> diff --git a/src/tag.c b/src/tag.c
> index 9eba4ee..2039e48 100644
> --- a/src/tag.c
> +++ b/src/tag.c
> @@ -53,6 +53,7 @@ struct near_tag {
>  	uint8_t nfcid_len;
>  
>  	uint8_t iso15693_dsfid;
> +	uint8_t iso15693_uid_len;
>  	uint8_t iso15693_uid[NFC_MAX_ISO15693_UID_LEN];
>  
>  	size_t data_length;
> @@ -168,6 +169,29 @@ static const char *type_string(struct near_tag *tag)
>  	return type;
>  }
>  
> +static const uint8_t uid_array(struct near_tag *tag, uint8_t **uid)
> +{
> +	if (tag->nfcid_len) {
> +		DBG("NFCID: ");
> +		for(int i = 0; i < tag->nfcid_len; i++)
                  ^^
nit: Please put a space between the 'for' and the "('.

> +			DBG("%x", tag->nfcid[i]);
> +
> +		*uid = tag->nfcid;
> +
> +		return tag->nfcid_len;
> +	} else if (tag->iso15693_uid_len) {
> +		DBG("ISO-UID: ");
> +		for(int i = 0; i < tag->iso15693_uid_len; i++)
                  ^^
nit: Please put a space between the 'for' and the "('.

Thanks,

Mark
--

Re: [PATCH] tag: Implement readout of tag UID via DBus interface

[Mark Greer]

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On Thu, Mar 11, 2021 at 09:50:20AM +0100, Schrempf Frieder wrote:
> From: Frieder Schrempf <frieder.schrempf@kontron.de>

Hi Frieder.

I am supposed to be taking over neard maintenance but I have been
completely derelict in my duties.  I need to refresh my brain's
cache and look at your patch in more detail.  In the meantime,
I have a few minor comments below.

> 
> This adds a 'Uid' property to the DBus interface for tags, which
> returns the UID of the tag as byte array.

Please add more high-level information to this commit description.
For example, what problem does it solve and how does it solve it?
Something that we can look back at in 5 years and be satisfied that
it solved a problem, that it solved the problem in reasonable way,
and that it was a change worth incorporating.

> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
> ---
>  src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 54 insertions(+), 3 deletions(-)
> 
> diff --git a/src/tag.c b/src/tag.c
> index 9eba4ee..2039e48 100644
> --- a/src/tag.c
> +++ b/src/tag.c
> @@ -53,6 +53,7 @@ struct near_tag {
>  	uint8_t nfcid_len;
>  
>  	uint8_t iso15693_dsfid;
> +	uint8_t iso15693_uid_len;
>  	uint8_t iso15693_uid[NFC_MAX_ISO15693_UID_LEN];
>  
>  	size_t data_length;
> @@ -168,6 +169,29 @@ static const char *type_string(struct near_tag *tag)
>  	return type;
>  }
>  
> +static const uint8_t uid_array(struct near_tag *tag, uint8_t **uid)
> +{
> +	if (tag->nfcid_len) {
> +		DBG("NFCID: ");
> +		for(int i = 0; i < tag->nfcid_len; i++)
                  ^^
nit: Please put a space between the 'for' and the "('.

> +			DBG("%x", tag->nfcid[i]);
> +
> +		*uid = tag->nfcid;
> +
> +		return tag->nfcid_len;
> +	} else if (tag->iso15693_uid_len) {
> +		DBG("ISO-UID: ");
> +		for(int i = 0; i < tag->iso15693_uid_len; i++)
                  ^^
nit: Please put a space between the 'for' and the "('.

Thanks,

Mark
--

[linux-nfc] Re: [PATCH] tag: Implement readout of tag UID via DBus interface

[Frieder Schrempf]

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Hi Mark,

On 12.03.21 02:21, Mark Greer wrote:
> On Thu, Mar 11, 2021@09:50:20AM +0100, Schrempf Frieder wrote:
>> From: Frieder Schrempf <frieder.schrempf@kontron.de>
> 
> Hi Frieder.
> 
> I am supposed to be taking over neard maintenance but I have been
> completely derelict in my duties.  I need to refresh my brain's
> cache and look@your patch in more detail.  In the meantime,
> I have a few minor comments below.

Good to hear that you are planning to take over maintainership. I was a 
bit worried to see neard being abandoned.

I also recently found out that Qt has abandoned their support for neard 
in Qt 6 [1], which means that Qt 5.15 is the last version to offer 
integration with neard.

I think that's very unfortunate as this provided a nice and mainline-ish 
stack for NFC devices from the kernel up to the application layer. I 
don't know the reasons for this decision, but neard looking like it is 
not maintained anymore is maybe one of them.

[1] https://bugreports.qt.io/browse/QTBUG-81824

> 
>>
>> This adds a 'Uid' property to the DBus interface for tags, which
>> returns the UID of the tag as byte array.
> 
> Please add more high-level information to this commit description.
> For example, what problem does it solve and how does it solve it?
> Something that we can look back@in 5 years and be satisfied that
> it solved a problem, that it solved the problem in reasonable way,
> and that it was a change worth incorporating.

Ok, I will improve the description to provide more information about 
what this does.

> 
>> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
>> ---
>>   src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 54 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/tag.c b/src/tag.c
>> index 9eba4ee..2039e48 100644
>> --- a/src/tag.c
>> +++ b/src/tag.c
>> @@ -53,6 +53,7 @@ struct near_tag {
>>   	uint8_t nfcid_len;
>>   
>>   	uint8_t iso15693_dsfid;
>> +	uint8_t iso15693_uid_len;
>>   	uint8_t iso15693_uid[NFC_MAX_ISO15693_UID_LEN];
>>   
>>   	size_t data_length;
>> @@ -168,6 +169,29 @@ static const char *type_string(struct near_tag *tag)
>>   	return type;
>>   }
>>   
>> +static const uint8_t uid_array(struct near_tag *tag, uint8_t **uid)
>> +{
>> +	if (tag->nfcid_len) {
>> +		DBG("NFCID: ");
>> +		for(int i = 0; i < tag->nfcid_len; i++)
>                    ^^
> nit: Please put a space between the 'for' and the "('.

Sure

> 
>> +			DBG("%x", tag->nfcid[i]);
>> +
>> +		*uid = tag->nfcid;
>> +
>> +		return tag->nfcid_len;
>> +	} else if (tag->iso15693_uid_len) {
>> +		DBG("ISO-UID: ");
>> +		for(int i = 0; i < tag->iso15693_uid_len; i++)
>                    ^^
> nit: Please put a space between the 'for' and the "('.

Sure

Thanks
Frieder

Re: [PATCH] tag: Implement readout of tag UID via DBus interface

[Frieder Schrempf]

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Hi Mark,

On 12.03.21 02:21, Mark Greer wrote:
> On Thu, Mar 11, 2021 at 09:50:20AM +0100, Schrempf Frieder wrote:
>> From: Frieder Schrempf <frieder.schrempf@kontron.de>
> 
> Hi Frieder.
> 
> I am supposed to be taking over neard maintenance but I have been
> completely derelict in my duties.  I need to refresh my brain's
> cache and look at your patch in more detail.  In the meantime,
> I have a few minor comments below.

Good to hear that you are planning to take over maintainership. I was a 
bit worried to see neard being abandoned.

I also recently found out that Qt has abandoned their support for neard 
in Qt 6 [1], which means that Qt 5.15 is the last version to offer 
integration with neard.

I think that's very unfortunate as this provided a nice and mainline-ish 
stack for NFC devices from the kernel up to the application layer. I 
don't know the reasons for this decision, but neard looking like it is 
not maintained anymore is maybe one of them.

[1] https://bugreports.qt.io/browse/QTBUG-81824

> 
>>
>> This adds a 'Uid' property to the DBus interface for tags, which
>> returns the UID of the tag as byte array.
> 
> Please add more high-level information to this commit description.
> For example, what problem does it solve and how does it solve it?
> Something that we can look back at in 5 years and be satisfied that
> it solved a problem, that it solved the problem in reasonable way,
> and that it was a change worth incorporating.

Ok, I will improve the description to provide more information about 
what this does.

> 
>> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
>> ---
>>   src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 54 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/tag.c b/src/tag.c
>> index 9eba4ee..2039e48 100644
>> --- a/src/tag.c
>> +++ b/src/tag.c
>> @@ -53,6 +53,7 @@ struct near_tag {
>>   	uint8_t nfcid_len;
>>   
>>   	uint8_t iso15693_dsfid;
>> +	uint8_t iso15693_uid_len;
>>   	uint8_t iso15693_uid[NFC_MAX_ISO15693_UID_LEN];
>>   
>>   	size_t data_length;
>> @@ -168,6 +169,29 @@ static const char *type_string(struct near_tag *tag)
>>   	return type;
>>   }
>>   
>> +static const uint8_t uid_array(struct near_tag *tag, uint8_t **uid)
>> +{
>> +	if (tag->nfcid_len) {
>> +		DBG("NFCID: ");
>> +		for(int i = 0; i < tag->nfcid_len; i++)
>                    ^^
> nit: Please put a space between the 'for' and the "('.

Sure

> 
>> +			DBG("%x", tag->nfcid[i]);
>> +
>> +		*uid = tag->nfcid;
>> +
>> +		return tag->nfcid_len;
>> +	} else if (tag->iso15693_uid_len) {
>> +		DBG("ISO-UID: ");
>> +		for(int i = 0; i < tag->iso15693_uid_len; i++)
>                    ^^
> nit: Please put a space between the 'for' and the "('.

Sure

Thanks
Frieder

[linux-nfc] Re: [PATCH] tag: Implement readout of tag UID via DBus interface

[Mark Greer]

[-- Attachment #1: Type: text/plain, Size: 1446 bytes --]

On Tue, Mar 16, 2021@09:53:21AM +0100, Frieder Schrempf wrote:
> Hi Mark,

Hi Frieder.

> On 12.03.21 02:21, Mark Greer wrote:
> > On Thu, Mar 11, 2021@09:50:20AM +0100, Schrempf Frieder wrote:
> > > From: Frieder Schrempf <frieder.schrempf@kontron.de>
> > 
> > Hi Frieder.
> > 
> > I am supposed to be taking over neard maintenance but I have been
> > completely derelict in my duties.  I need to refresh my brain's
> > cache and look@your patch in more detail.  In the meantime,
> > I have a few minor comments below.
> 
> Good to hear that you are planning to take over maintainership. I was a bit
> worried to see neard being abandoned.

Just a warning that I have precious little time to dedicate to this so
please set expectations accordingly.

> I also recently found out that Qt has abandoned their support for neard in
> Qt 6 [1], which means that Qt 5.15 is the last version to offer integration
> with neard.
> 
> I think that's very unfortunate as this provided a nice and mainline-ish
> stack for NFC devices from the kernel up to the application layer. I don't
> know the reasons for this decision, but neard looking like it is not
> maintained anymore is maybe one of them.
> 
> [1] https://bugreports.qt.io/browse/QTBUG-81824

Thank you for the heads up and link.  This is disappointing.  I'll reach
out to them and see what their current thoughts are and whether they'll
reconsider.

Mark
--

Re: [PATCH] tag: Implement readout of tag UID via DBus interface

[Mark Greer]

[-- Attachment #1: Type: text/plain, Size: 1455 bytes --]

On Tue, Mar 16, 2021 at 09:53:21AM +0100, Frieder Schrempf wrote:
> Hi Mark,

Hi Frieder.

> On 12.03.21 02:21, Mark Greer wrote:
> > On Thu, Mar 11, 2021 at 09:50:20AM +0100, Schrempf Frieder wrote:
> > > From: Frieder Schrempf <frieder.schrempf@kontron.de>
> > 
> > Hi Frieder.
> > 
> > I am supposed to be taking over neard maintenance but I have been
> > completely derelict in my duties.  I need to refresh my brain's
> > cache and look at your patch in more detail.  In the meantime,
> > I have a few minor comments below.
> 
> Good to hear that you are planning to take over maintainership. I was a bit
> worried to see neard being abandoned.

Just a warning that I have precious little time to dedicate to this so
please set expectations accordingly.

> I also recently found out that Qt has abandoned their support for neard in
> Qt 6 [1], which means that Qt 5.15 is the last version to offer integration
> with neard.
> 
> I think that's very unfortunate as this provided a nice and mainline-ish
> stack for NFC devices from the kernel up to the application layer. I don't
> know the reasons for this decision, but neard looking like it is not
> maintained anymore is maybe one of them.
> 
> [1] https://bugreports.qt.io/browse/QTBUG-81824

Thank you for the heads up and link.  This is disappointing.  I'll reach
out to them and see what their current thoughts are and whether they'll
reconsider.

Mark
--