l4/pkg/io/io/server/src/inhibitor_mux.cc

   1 #include "inhibitor_mux.h"
   2 #include <l4/sys/err.h>
   3 #include <cstring>
   4
   5 Inhibitor_provider::Inhibitor_provider(Inhibitor_mux *mux)
   6 : _mux(mux)
   7 {
   8   _mux->_clients.add(this);
   9   for (unsigned i = 0; i < L4VBUS_INHIBITOR_MAX; ++i)
  10     {
  11       _inhibitor_acquired[i] = false;
  12       _inhibitor_reason[i][0] = 0;
  13     }
  14 }
  15
  16 Inhibitor_provider::~Inhibitor_provider()
  17 {
  18   _mux->_clients.remove(this);
  19
  20   for (unsigned i = 0; i < L4VBUS_INHIBITOR_MAX; ++i)
  21     if (_inhibitor_acquired[i])
  22       _mux->inhibitor_release(i);
  23 }
  24
  25 void
  26 Inhibitor_provider::inhibitor_acquire(l4_umword_t id, char const *reason)
  27 {
  28   if (id >= L4VBUS_INHIBITOR_MAX)
  29     throw -L4_ERANGE;
  30
  31   if (_inhibitor_acquired[id])
  32     return; // already acquired, just ignore
  33
  34   unsigned long len = sizeof (_inhibitor_reason[id]);
  35   strncpy(_inhibitor_reason[id], reason, len);
  36   _inhibitor_reason[id][len - 1] = 0;
  37   _inhibitor_acquired[id] = true;
  38   _mux->inhibitor_acquire(id);
  39 }
  40
  41 /**
  42  * \brief Release an inhibitor lock and unsubscribe the client from the
  43  *        corresponding signal.
  44  *
  45  * \param id Id of inhibitor lock to release.
  46  */
  47 void
  48 Inhibitor_provider::inhibitor_release(l4_umword_t id)
  49 {
  50   if (id >= L4VBUS_INHIBITOR_MAX)
  51     throw -L4_ERANGE;
  52
  53   if (!_inhibitor_acquired[id])
  54     return; // not acquired, just ignore
  55
  56   _inhibitor_acquired[id] = false;
  57   _inhibitor_reason[id][0] = 0;
  58   _mux->inhibitor_release(id);
  59 }
  60
  61 /**
  62  * \brief Tell the mux that a client has taken a lock.
  63  *
  64  * Called by the Inhibitor_provider.
  65  *
  66  * \param id Id of lock that was taken.
  67  */
  68 void
  69 Inhibitor_mux::inhibitor_acquire(l4_umword_t id)
  70 {
  71   if (id >= L4VBUS_INHIBITOR_MAX)
  72     throw -L4_ERANGE;
  73
  74   ++_inhibitors_acquired[id];
  75 }
  76
  77 /**
  78  * \brief Tell the mux that a client released a lock.
  79  *
  80  * Called by the Inhibitor_provider. If the released lock was the last of its
  81  * kind being held, all_inhibitors_free(type) will be called.
  82  *
  83  * \param id ID of the inhibitor_lock that was released.
  84  */
  85 void
  86 Inhibitor_mux::inhibitor_release(l4_umword_t id)
  87 {
  88   if (id >= L4VBUS_INHIBITOR_MAX)
  89     throw -L4_ERANGE;
  90
  91   if (!--_inhibitors_acquired[id])
  92     all_inhibitors_free(id);
  93 }
  94