servers/ds/main.c

   1 /* Data Store Server.
   2  * This service implements a little publish/subscribe data store that is
   3  * crucial for the system's fault tolerance. Components that require state
   4  * can store it here, for later retrieval, e.g., after a crash and subsequent
   5  * restart by the reincarnation server.
   6  *
   7  * Created:
   8  *   Oct 19, 2005       by Jorrit N. Herder
   9  */
  10
  11 #include "inc.h"        /* include master header file */
  12 #include <minix/endpoint.h>
  13
  14 /* Allocate space for the global variables. */
  15 static endpoint_t who_e;        /* caller's proc number */
  16 static int callnr;              /* system call number */
  17
  18 /* Declare some local functions. */
  19 static void get_work(message *m_ptr);
  20 static void reply(endpoint_t whom, message *m_ptr);
  21
  22 /* SEF functions and variables. */
  23 static void sef_local_startup(void);
  24
  25 /*===========================================================================*
  26  *                              main                                         *
  27  *===========================================================================*/
  28 int main(int argc, char **argv)
  29 {
  30 /* This is the main routine of this service. The main loop consists of
  31  * three major activities: getting new work, processing the work, and
  32  * sending the reply. The loop never terminates, unless a panic occurs.
  33  */
  34   message m;
  35   int result;
  36
  37   /* SEF local startup. */
  38   env_setargs(argc, argv);
  39   sef_local_startup();
  40
  41   /* Main loop - get work and do it, forever. */
  42   while (TRUE) {
  43
  44       /* Wait for incoming message, sets 'callnr' and 'who'. */
  45       get_work(&m);
  46
  47       if (is_notify(callnr)) {
  48           printf("DS: warning, got illegal notify from: %d\n", m.m_source);
  49           result = EINVAL;
  50           goto send_reply;
  51       }
  52
  53       switch (callnr) {
  54       case DS_PUBLISH:
  55           result = do_publish(&m);
  56           break;
  57       case DS_RETRIEVE:
  58           result = do_retrieve(&m);
  59           break;
  60       case DS_RETRIEVE_LABEL:
  61           result = do_retrieve_label(&m);
  62           break;
  63       case DS_DELETE:
  64           result = do_delete(&m);
  65           break;
  66       case DS_SUBSCRIBE:
  67           result = do_subscribe(&m);
  68           break;
  69       case DS_CHECK:
  70           result = do_check(&m);
  71           break;
  72       case DS_SNAPSHOT:
  73           result = do_snapshot(&m);
  74           break;
  75       case COMMON_GETSYSINFO:
  76           result = do_getsysinfo(&m);
  77           break;
  78       default:
  79           printf("DS: warning, got illegal request from %d\n", m.m_source);
  80           result = EINVAL;
  81       }
  82
  83 send_reply:
  84       /* Finally send reply message, unless disabled. */
  85       if (result != EDONTREPLY) {
  86           m.m_type = result;            /* build reply message */
  87           reply(who_e, &m);             /* send it away */
  88       }
  89   }
  90   return(OK);                           /* shouldn't come here */
  91 }
  92
  93 /*===========================================================================*
  94  *                             sef_local_startup                             *
  95  *===========================================================================*/
  96 static void sef_local_startup()
  97 {
  98   /* Register init callbacks. */
  99   sef_setcb_init_fresh(sef_cb_init_fresh);
 100   sef_setcb_init_restart(sef_cb_init_fail);
 101
 102   /* No live update support for now. */
 103
 104   /* Let SEF perform startup. */
 105   sef_startup();
 106 }
 107
 108 /*===========================================================================*
 109  *                              get_work                                     *
 110  *===========================================================================*/
 111 static void get_work(
 112   message *m_ptr                        /* message buffer */
 113 )
 114 {
 115     int status = sef_receive(ANY, m_ptr);   /* blocks until message arrives */
 116     if (OK != status)
 117         panic("failed to receive message!: %d", status);
 118     who_e = m_ptr->m_source;        /* message arrived! set sender */
 119     callnr = m_ptr->m_type;       /* set function call number */
 120 }
 121
 122 /*===========================================================================*
 123  *                              reply                                        *
 124  *===========================================================================*/
 125 static void reply(
 126   endpoint_t who_e,                     /* destination */
 127   message *m_ptr                        /* message buffer */
 128 )
 129 {
 130     int s = send(who_e, m_ptr);    /* send the message */
 131     if (OK != s)
 132         printf("DS: unable to send reply to %d: %d\n", who_e, s);
 133 }
 134