lib/libsys/sef_signal.c

   1 #include "syslib.h"
   2 #include <assert.h>
   3 #include <signal.h>
   4 #include <minix/sysutil.h>
   5
   6 /* SEF Signal callbacks. */
   7 static struct sef_cbs {
   8     sef_cb_signal_handler_t             sef_cb_signal_handler;
   9     sef_cb_signal_manager_t             sef_cb_signal_manager;
  10 } sef_cbs = {
  11     SEF_CB_SIGNAL_HANDLER_DEFAULT,
  12     SEF_CB_SIGNAL_MANAGER_DEFAULT
  13 };
  14
  15 /* SEF Signal prototypes for sef_receive(). */
  16 int do_sef_signal_request(message *m_ptr);
  17
  18 /* Debug. */
  19 EXTERN char* sef_debug_header(void);
  20
  21 /* Information about SELF. */
  22 EXTERN endpoint_t sef_self_endpoint;
  23
  24 /*===========================================================================*
  25  *                         process_sigmgr_signals                            *
  26  *===========================================================================*/
  27 static void process_sigmgr_signals(void)
  28 {
  29 /* A signal manager has pending signals in the kernel. Process them. */
  30   endpoint_t target;
  31   sigset_t sigset;
  32   int signo, r;
  33
  34   while (TRUE) {
  35       /* Get an arbitrary pending signal. */
  36       if((r=sys_getksig(&target, &sigset)) != OK)
  37           panic("SEF: sys_getksig failed: %d", r);
  38
  39       if (target == NONE) {
  40           /* Stop if there are no more pending signals. */
  41           break;
  42       } else {
  43           /* Process every signal in the signal set. */
  44           r = OK;
  45           for (signo = SIGS_FIRST; signo <= SIGS_LAST; signo++) {
  46               if(sigismember(&sigset, signo)) {
  47                   /* Let the callback code process the signal. */
  48                   r = sef_cbs.sef_cb_signal_manager(target, signo);
  49
  50                   /* Stop if process is gone. */
  51                   if(r == EDEADSRCDST) {
  52                       break;
  53                   }
  54               }
  55           }
  56           /* Tell the kernel we are done if the target is still alive. */
  57           if(r == OK) {
  58               if((r=sys_endksig(target)) != OK)
  59                   panic("SEF: sys_endksig failed :%d", r);
  60           }
  61       }
  62   }
  63 }
  64
  65 /*===========================================================================*
  66  *                         process_sigmgr_self_signals                       *
  67  *===========================================================================*/
  68 static void process_sigmgr_self_signals(sigset_t sigset)
  69 {
  70 /* A signal manager has pending signals for itself. Process them. */
  71   int signo;
  72
  73   for (signo = SIGS_FIRST; signo <= SIGS_LAST; signo++) {
  74       if(sigismember(&sigset, signo)) {
  75           /* Let the callback code process the signal. */
  76           sef_cbs.sef_cb_signal_handler(signo);
  77       }
  78   }
  79 }
  80
  81 /*===========================================================================*
  82  *                           do_sef_signal_request                           *
  83  *===========================================================================*/
  84 int do_sef_signal_request(message *m_ptr)
  85 {
  86 /* Handle a SEF Signal request. */
  87   int signo;
  88   sigset_t sigset;
  89
  90   if(m_ptr->m_source == SYSTEM) {
  91       /* Handle kernel signals. */
  92       sigset = m_ptr->NOTIFY_ARG;
  93       for (signo = SIGK_FIRST; signo <= SIGK_LAST; signo++) {
  94           if (sigismember(&sigset, signo)) {
  95               /* Let the callback code handle the kernel signal. */
  96               sef_cbs.sef_cb_signal_handler(signo);
  97
  98               /* Handle SIGKSIG for a signal manager. */
  99               if(signo == SIGKSIG) {
 100                   process_sigmgr_signals();
 101               }
 102               /* Handle SIGKSIGSM for a signal manager. */
 103               else if(signo == SIGKSIGSM) {
 104                   process_sigmgr_self_signals(sigset);
 105               }
 106           }
 107       }
 108   }
 109   else {
 110       /* Handle system signals from a signal manager. */
 111       signo = m_ptr->SIGS_SIG_NUM;
 112
 113       /* Debug. */
 114 #if SEF_SIGNAL_DEBUG
 115       sef_signal_debug_begin();
 116       sef_signal_dprint("%s. Got a SEF Signal request for signal %d! About to handle signal.\n",
 117           sef_debug_header(), signo);
 118       sef_signal_debug_end();
 119 #endif
 120
 121       /* Let the callback code handle the signal. */
 122       sef_cbs.sef_cb_signal_handler(signo);
 123   }
 124
 125   /* Return OK not to let anybody else intercept the request. */
 126   return OK;
 127 }
 128
 129 /*===========================================================================*
 130  *                        sef_setcb_signal_handler                           *
 131  *===========================================================================*/
 132 void sef_setcb_signal_handler(sef_cb_signal_handler_t cb)
 133 {
 134   assert(cb != NULL);
 135   sef_cbs.sef_cb_signal_handler = cb;
 136 }
 137
 138 /*===========================================================================*
 139  *                        sef_setcb_signal_manager                           *
 140  *===========================================================================*/
 141 void sef_setcb_signal_manager(sef_cb_signal_manager_t cb)
 142 {
 143   assert(cb != NULL);
 144   sef_cbs.sef_cb_signal_manager = cb;
 145 }
 146
 147 /*===========================================================================*
 148  *                        sef_cb_signal_handler_null                         *
 149  *===========================================================================*/
 150 void sef_cb_signal_handler_null(int signo)
 151 {
 152 }
 153
 154 /*===========================================================================*
 155  *                        sef_cb_signal_manager_null                         *
 156  *===========================================================================*/
 157 int sef_cb_signal_manager_null(endpoint_t target, int signo)
 158 {
 159   return OK;
 160 }
 161
 162 /*===========================================================================*
 163  *                        sef_cb_signal_handler_term                         *
 164  *===========================================================================*/
 165 void sef_cb_signal_handler_term(int signo)
 166 {
 167   /* Terminate in case of SIGTERM, ignore other signals. */
 168   if(signo == SIGTERM) {
 169       sef_exit(1);
 170   }
 171 }
 172
 173 /*===========================================================================*
 174  *                    sef_cb_signal_handler_posix_default                    *
 175  *===========================================================================*/
 176 void sef_cb_signal_handler_posix_default(int signo)
 177 {
 178   switch(signo) {
 179       /* Ignore when possible. */
 180       case SIGCHLD:
 181       case SIGWINCH:
 182       case SIGCONT:
 183       case SIGTSTP:
 184       case SIGTTIN:
 185       case SIGTTOU:
 186       break;
 187
 188       /* Terminate in any other case unless it is a kernel signal. */
 189       default:
 190           if(!IS_SIGK(signo)) {
 191               sef_exit(1);
 192           }
 193       break;
 194   }
 195 }
 196