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               int s = sigismember(&sigset, signo);
  47               assert(s >= 0);
  48               if(s) {
  49                   /* Let the callback code process the signal. */
  50                   r = sef_cbs.sef_cb_signal_manager(target, signo);
  51
  52                   /* Stop if process is gone. */
  53                   if(r == EDEADSRCDST) {
  54                       break;
  55                   }
  56               }
  57           }
  58           /* Tell the kernel we are done if the target is still alive. */
  59           if(r == OK) {
  60               if((r=sys_endksig(target)) != OK)
  61                   panic("SEF: sys_endksig failed :%d", r);
  62           }
  63       }
  64   }
  65 }
  66
  67 /*===========================================================================*
  68  *                         process_sigmgr_self_signals                       *
  69  *===========================================================================*/
  70 static void process_sigmgr_self_signals(sigset_t sigset)
  71 {
  72 /* A signal manager has pending signals for itself. Process them. */
  73   int signo;
  74
  75   for (signo = SIGS_FIRST; signo <= SIGS_LAST; signo++) {
  76       int s = sigismember(&sigset, signo);
  77       assert(s >= 0);
  78       if(s) {
  79           /* Let the callback code process the signal. */
  80           sef_cbs.sef_cb_signal_handler(signo);
  81       }
  82   }
  83 }
  84
  85 /*===========================================================================*
  86  *                           do_sef_signal_request                           *
  87  *===========================================================================*/
  88 int do_sef_signal_request(message *m_ptr)
  89 {
  90 /* Handle a SEF Signal request. */
  91   int signo;
  92   sigset_t sigset;
  93
  94   if(m_ptr->m_source == SYSTEM) {
  95       /* Handle kernel signals. */
  96       sigset = m_ptr->m_notify.sigset;
  97       for (signo = SIGK_FIRST; signo <= SIGK_LAST; signo++) {
  98           int s = sigismember(&sigset, signo);
  99           assert(s >= 0);
 100           if (s) {
 101               /* Let the callback code handle the kernel signal. */
 102               sef_cbs.sef_cb_signal_handler(signo);
 103
 104               /* Handle SIGKSIG for a signal manager. */
 105               if(signo == SIGKSIG) {
 106                   process_sigmgr_signals();
 107               }
 108               /* Handle SIGKSIGSM for a signal manager. */
 109               else if(signo == SIGKSIGSM) {
 110                   process_sigmgr_self_signals(sigset);
 111               }
 112           }
 113       }
 114   }
 115   else {
 116       /* Handle system signals from a signal manager. */
 117       signo = m_ptr->SIGS_SIG_NUM;
 118
 119       /* Debug. */
 120 #if SEF_SIGNAL_DEBUG
 121       sef_signal_debug_begin();
 122       sef_signal_dprint("%s. Got a SEF Signal request for signal %d! About to handle signal.\n",
 123           sef_debug_header(), signo);
 124       sef_signal_debug_end();
 125 #endif
 126
 127       /* Let the callback code handle the signal. */
 128       sef_cbs.sef_cb_signal_handler(signo);
 129   }
 130
 131   /* Return OK not to let anybody else intercept the request. */
 132   return OK;
 133 }
 134
 135 /*===========================================================================*
 136  *                        sef_setcb_signal_handler                           *
 137  *===========================================================================*/
 138 void sef_setcb_signal_handler(sef_cb_signal_handler_t cb)
 139 {
 140   assert(cb != NULL);
 141   sef_cbs.sef_cb_signal_handler = cb;
 142 }
 143
 144 /*===========================================================================*
 145  *                        sef_setcb_signal_manager                           *
 146  *===========================================================================*/
 147 void sef_setcb_signal_manager(sef_cb_signal_manager_t cb)
 148 {
 149   assert(cb != NULL);
 150   sef_cbs.sef_cb_signal_manager = cb;
 151 }
 152
 153 /*===========================================================================*
 154  *                        sef_cb_signal_handler_null                         *
 155  *===========================================================================*/
 156 void sef_cb_signal_handler_null(int signo)
 157 {
 158 }
 159
 160 /*===========================================================================*
 161  *                        sef_cb_signal_manager_null                         *
 162  *===========================================================================*/
 163 int sef_cb_signal_manager_null(endpoint_t target, int signo)
 164 {
 165   return OK;
 166 }
 167
 168 /*===========================================================================*
 169  *                        sef_cb_signal_handler_term                         *
 170  *===========================================================================*/
 171 void sef_cb_signal_handler_term(int signo)
 172 {
 173   /* Terminate in case of SIGTERM, ignore other signals. */
 174   if(signo == SIGTERM) {
 175       sef_exit(1);
 176   }
 177 }
 178
 179 /*===========================================================================*
 180  *                    sef_cb_signal_handler_posix_default                    *
 181  *===========================================================================*/
 182 void sef_cb_signal_handler_posix_default(int signo)
 183 {
 184   switch(signo) {
 185       /* Ignore when possible. */
 186       case SIGCHLD:
 187       case SIGWINCH:
 188       case SIGCONT:
 189       case SIGTSTP:
 190       case SIGTTIN:
 191       case SIGTTOU:
 192       break;
 193
 194       /* Terminate in any other case unless it is a kernel signal. */
 195       default:
 196           if(!IS_SIGK(signo)) {
 197               sef_exit(1);
 198           }
 199       break;
 200   }
 201 }
 202