Hi Fabian, On 16.03.21 19:49, Gottstein, Fabian wrote: > Hi Frieder, > > thanks for the patch. thanks for your feedback. > > Could you please also consider the following situation: > In the case of a NFC Tag Type 1, the identifier is delivered via the RID command (see NFC Digital Protocol). Thus, the Tag's nfcid property is updated in a later step. > To inform the neard users, a property changed signal has to be emitted when nfcid has changed (in near_tag_set_nfcid). Also, a exists() handler for the new DBus property should be implemented. I'm new to NFC and D-Bus, so I don't know much about what use-cases and requirements there are. Your request sounds reasonable and I think I have a rough understanding of what is probably needed to implement this. Still to actually do this I need to look@the specifications and the code more closely and I don't know if/when I will find time to do this. Also I don't have any hardware to test this with NFC type 1 tags. > > Another thing regarding building the response message: > The following code snippet could simplify and improve the readability of the usage of the dbus message builder: > > dbus_message_iter_open_container(iter, DBUS_TYPE_ARRAY, DBUS_TYPE_BYTE_AS_STRING, &entry); > dbus_message_iter_append_fixed_array(&entry, DBUS_TYPE_BYTE, &uid, len); > dbus_message_iter_close_container(iter, &entry); > Thanks for the improved code, I will use this instead. Frieder > > > -----Original Message----- > From: Schrempf Frieder > Sent: Dienstag, 16. März 2021 12:22 > To: Samuel Ortiz ; linux-nfc@lists.01.org > Cc: Frieder Schrempf > Subject: [linux-nfc] [PATCH v2] tag: Implement readout of tag UID via DBus interface > > Caution: This e-mail originated from outside of Philips, be careful for phishing. > > > From: Frieder Schrempf > > NFC tags usually provide an unique identifier. Neard already checks if one of the two types of identifiers is available, reads them from tags and stores them in near_tag.nfcid or near_tag.iso15693_uid respectively. > > Though currently it is not possible for any client application to get this information via the D-Bus interface as no property for the UID is implemented. > > This adds a 'Uid' property to the D-Bus interface for tags, which exposes the UID of the tag as byte array. If nfcid is available this is returned as UID, otherwise if iso15693_uid is available this is returned. If no UID is available, no 'Uid' property is exposed. > > Signed-off-by: Frieder Schrempf > --- > Changes in v2: > * Add whitespaces after 'for' statements > * Add more details to the commit message > --- > src/tag.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 54 insertions(+), 3 deletions(-) > > diff --git a/src/tag.c b/src/tag.c > index 9eba4ee..d530893 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 mailing list -- linux-nfc@lists.01.org To unsubscribe send an email to linux-nfc-leave@lists.01.org %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s > > ________________________________ > The information contained in this message may be confidential and legally protected under applicable law. 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