minix3/servers/ds/main.c

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2020-02-21 00:59:27 +05:30
/* Data Store Server.
* This service implements a little publish/subscribe data store that is
* crucial for the system's fault tolerance. Components that require state
* can store it here, for later retrieval, e.g., after a crash and subsequent
* restart by the reincarnation server.
*
* Created:
* Oct 19, 2005 by Jorrit N. Herder
*/
#include "inc.h" /* include master header file */
#include <minix/endpoint.h>
/* Allocate space for the global variables. */
static endpoint_t who_e; /* caller's proc number */
static int callnr; /* system call number */
/* Declare some local functions. */
static void get_work(message *m_ptr);
static void reply(endpoint_t whom, message *m_ptr);
/* SEF functions and variables. */
static void sef_local_startup(void);
/*===========================================================================*
* main *
*===========================================================================*/
int main(int argc, char **argv)
{
/* This is the main routine of this service. The main loop consists of
* three major activities: getting new work, processing the work, and
* sending the reply. The loop never terminates, unless a panic occurs.
*/
message m;
int result;
/* SEF local startup. */
env_setargs(argc, argv);
sef_local_startup();
/* Main loop - get work and do it, forever. */
while (TRUE) {
/* Wait for incoming message, sets 'callnr' and 'who'. */
get_work(&m);
if (is_notify(callnr)) {
printf("DS: warning, got illegal notify from: %d\n", m.m_source);
result = EINVAL;
goto send_reply;
}
switch (callnr) {
case DS_PUBLISH:
result = do_publish(&m);
break;
case DS_RETRIEVE:
result = do_retrieve(&m);
break;
case DS_RETRIEVE_LABEL:
result = do_retrieve_label(&m);
break;
case DS_DELETE:
result = do_delete(&m);
break;
case DS_SUBSCRIBE:
result = do_subscribe(&m);
break;
case DS_CHECK:
result = do_check(&m);
break;
case DS_GETSYSINFO:
result = do_getsysinfo(&m);
break;
default:
printf("DS: warning, got illegal request from %d\n", m.m_source);
result = EINVAL;
}
send_reply:
/* Finally send reply message, unless disabled. */
if (result != EDONTREPLY) {
m.m_type = result; /* build reply message */
reply(who_e, &m); /* send it away */
}
}
return(OK); /* shouldn't come here */
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
static void sef_local_startup()
{
/* Register init callbacks. */
sef_setcb_init_fresh(sef_cb_init_fresh);
sef_setcb_init_restart(sef_cb_init_fail);
/* No live update support for now. */
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* get_work *
*===========================================================================*/
static void get_work(
message *m_ptr /* message buffer */
)
{
int status = sef_receive(ANY, m_ptr); /* blocks until message arrives */
if (OK != status)
panic("failed to receive message!: %d", status);
who_e = m_ptr->m_source; /* message arrived! set sender */
callnr = m_ptr->m_type; /* set function call number */
}
/*===========================================================================*
* reply *
*===========================================================================*/
static void reply(
endpoint_t who_e, /* destination */
message *m_ptr /* message buffer */
)
{
int s = ipc_send(who_e, m_ptr); /* send the message */
if (OK != s)
printf("DS: unable to send reply to %d: %d\n", who_e, s);
}