libcacard: initial commit

libcacard emulates a Common Access Card (CAC) which is a standard
for smartcards. It is used by the emulated ccid card introduced in
a following patch. Docs are available in docs/libcacard.txt

Signed-off-by: Alon Levy <alevy@redhat.com>

---

changes from v24->v25:
 * Fix out of tree builds.
 * Fix build with linux-user targets.

changes from v23->v24: (Jes Sorensen review 2)
 * Makefile.target: use obj-$(CONFIG_*) +=
 * remove unrequired includes, include qemu-common before qemu-thread
  * required adding #define NO_NSPR_10_SUPPORT (harmless)

changes from v22->v23:
 * configure fixes: (reported by Stefan Hajnoczi)
  * test a = b, not a == b (second isn't portable)
  * quote $source_path in case it contains spaces
   - this doesn't really help since there are many other places
     that need similar fixes, not introduced by this patch.

changes from v21->v22:
 * fix configure to not link libcacard if nss not found
    (reported by Stefan Hajnoczi)
 * fix vscclient linkage with simpletrace backend
    (reported by Stefan Hajnoczi)
 * card_7816.c: add missing break in ERROR_DATA_NOT_FOUND
    (reported by William van de Velde)

changes from v20->v21: (Jes Sorensen review)
 * use qemu infrastructure: qemu-thread, qemu-common (qemu_malloc
  and qemu_free), error_report
 * assert instead of ASSERT
 * cosmetic fixes
 * use strpbrk and isspace
 * add --disable-nss --enable-nss here, instead of in the final patch.
 * split vscclient, passthru and docs to following patches.

changes from v19->v20:
 * checkpatch.pl

changes from v15->v16:

Build:
 * don't erase self with distclean
 * fix make clean after make distclean
 * Makefile: make vscclient link quiet

Behavioral:
 * vcard_emul_nss: load coolkey in more situations
 * vscclient:
  * use hton,ntoh
  * send init on connect, only start vevent thread on response
  * read payload after header check, before type switch
  * remove Reconnect
  * update for vscard_common changes, empty Flush implementation

Style/Whitespace:
 * fix wrong variable usage
 * remove unused variable
 * use only C style comments
  * add copyright header
  * fix tabulation

Signed-off-by: Alon Levy <alevy@redhat.com>

libcacard: fix out of tree builds

libcacard/event.c

@@ -0,0 +1,106 @@
+/*
+ * event queue implementation.
+ *
+ * This code is licensed under the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qemu-common.h"
+#include "qemu-thread.h"
+
+#include "vcard.h"
+#include "vreader.h"
+#include "vevent.h"
+
+VEvent *
+vevent_new(VEventType type, VReader *reader, VCard *card)
+{
+    VEvent *new_vevent;
+
+    new_vevent = (VEvent *)qemu_malloc(sizeof(VEvent));
+    new_vevent->next = NULL;
+    new_vevent->type = type;
+    new_vevent->reader = vreader_reference(reader);
+    new_vevent->card = vcard_reference(card);
+
+    return new_vevent;
+}
+
+void
+vevent_delete(VEvent *vevent)
+{
+    if (vevent == NULL) {
+        return;
+    }
+    vreader_free(vevent->reader);
+    vcard_free(vevent->card);
+    qemu_free(vevent);
+}
+
+/*
+ * VEvent queue management
+ */
+
+static VEvent *vevent_queue_head;
+static VEvent *vevent_queue_tail;
+static QemuMutex vevent_queue_lock;
+static QemuCond vevent_queue_condition;
+
+void vevent_queue_init(void)
+{
+    qemu_mutex_init(&vevent_queue_lock);
+    qemu_cond_init(&vevent_queue_condition);
+    vevent_queue_head = vevent_queue_tail = NULL;
+}
+
+void
+vevent_queue_vevent(VEvent *vevent)
+{
+    vevent->next = NULL;
+    qemu_mutex_lock(&vevent_queue_lock);
+    if (vevent_queue_head) {
+        assert(vevent_queue_tail);
+        vevent_queue_tail->next = vevent;
+    } else {
+        vevent_queue_head = vevent;
+    }
+    vevent_queue_tail = vevent;
+    qemu_cond_signal(&vevent_queue_condition);
+    qemu_mutex_unlock(&vevent_queue_lock);
+}
+
+/* must have lock */
+static VEvent *
+vevent_dequeue_vevent(void)
+{
+    VEvent *vevent = NULL;
+    if (vevent_queue_head) {
+        vevent = vevent_queue_head;
+        vevent_queue_head = vevent->next;
+        vevent->next = NULL;
+    }
+    return vevent;
+}
+
+VEvent *vevent_wait_next_vevent(void)
+{
+    VEvent *vevent;
+
+    qemu_mutex_lock(&vevent_queue_lock);
+    while ((vevent = vevent_dequeue_vevent()) == NULL) {
+        qemu_cond_wait(&vevent_queue_condition, &vevent_queue_lock);
+    }
+    qemu_mutex_unlock(&vevent_queue_lock);
+    return vevent;
+}
+
+VEvent *vevent_get_next_vevent(void)
+{
+    VEvent *vevent;
+
+    qemu_mutex_lock(&vevent_queue_lock);
+    vevent = vevent_dequeue_vevent();
+    qemu_mutex_unlock(&vevent_queue_lock);
+    return vevent;
+}
+