From 0b42cbfb8f9dfd21b7ddb5c3a409a19d995967f1 Mon Sep 17 00:00:00 2001
From: Romuald Conty <romuald@libnfc.org>
Date: Mon, 27 Jun 2011 09:14:19 +0000
Subject: [PATCH] examples/nfc-emulate-forum-tag4: this example now fails with
 ENOTSUPP when used with a non-PN532 chip.

---
 examples/nfc-emulate-forum-tag4.c | 20 ++++++++++----------
 libnfc/chips/pn53x.c              |  6 ++++++
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/examples/nfc-emulate-forum-tag4.c b/examples/nfc-emulate-forum-tag4.c
index 800ab35..9b99ec3 100644
--- a/examples/nfc-emulate-forum-tag4.c
+++ b/examples/nfc-emulate-forum-tag4.c
@@ -112,17 +112,17 @@ nfcforum_tag4_io (struct nfc_emulator *emulator, const byte_t *data_in, const si
   struct nfcforum_tag4_ndef_data *ndef_data = (struct nfcforum_tag4_ndef_data *)(emulator->user_data);
   struct nfcforum_tag4_state_machine_data *state_machine_data = (struct nfcforum_tag4_state_machine_data *)(emulator->state_machine->data);
 
+  if (data_in_len == 0) {
+    // No input data, nothing to do
+    return res;
+  }
+
   // Show transmitted command
   if (!quiet_output) {
     printf ("    In: ");
     print_hex (data_in, data_in_len);
   }
 
-  if ((data_in_len == 2) && (data_in[0] == ISO144434A_RATS)) {
-    // The PN532 already handle RATS, so there is nothing to do
-    return res;
-  }
-
   if(data_in_len >= 4) {
     if (data_in[CLA] != 0x00)
       return -ENOTSUP;
@@ -168,7 +168,6 @@ nfcforum_tag4_io (struct nfc_emulator *emulator, const byte_t *data_in, const si
         return -ENOTSUP;
       }
 
-
       break;
     case ISO7816_READ_BINARY:
       if ((size_t)(data_in[LC] + 2) > data_out_len) {
@@ -210,11 +209,12 @@ nfcforum_tag4_io (struct nfc_emulator *emulator, const byte_t *data_in, const si
 
   // Show transmitted command
   if (!quiet_output) {
-    printf ("    Out: ");
-    if (res < 0)
-      printf ("No data (returning with an error %d)\n", res);
-    else
+    if (res < 0) {
+      ERR ("%s (%d)", strerror (-res), -res);
+    } else {
+      printf ("    Out: ");
       print_hex (data_out, res);
+    }
   }
   return res;
 }
diff --git a/libnfc/chips/pn53x.c b/libnfc/chips/pn53x.c
index 4c76775..8099765 100644
--- a/libnfc/chips/pn53x.c
+++ b/libnfc/chips/pn53x.c
@@ -1629,6 +1629,12 @@ pn53x_target_init (nfc_device_t * pnd, nfc_target_t * pnt, byte_t * pbtRx, size_
       }
       CHIP_DATA (pnd)->current_target = malloc (sizeof(nfc_target_t));
       memcpy (CHIP_DATA (pnd)->current_target, pnt, sizeof(nfc_target_t));
+
+      if (ptm & PTM_ISO14443_4_PICC_ONLY) {
+	// When PN532 is in PICC target mode, it automatically reply to RATS so
+	// we don't need to forward this command
+        *pszRx = 0;
+      }
     }
   }