7967177710
'who', indicating caller number in pm and fs and some other servers, has been removed in favour of 'who_e' (endpoint) and 'who_p' (proc nr.). In both PM and FS, isokendpt() convert endpoints to process slot numbers, returning OK if it was a valid and consistent endpoint number. okendpt() does the same but panic()s if it doesn't succeed. (In PM, this is pm_isok..) pm and fs keep their own records of process endpoints in their proc tables, which are needed to make kernel calls about those processes. message field names have changed. fs drivers are endpoints. fs now doesn't try to get out of driver deadlock, as the protocol isn't supposed to let that happen any more. (A warning is printed if ELOCKED is detected though.) fproc[].fp_task (indicating which driver the process is suspended on) became an int. PM and FS now get endpoint numbers of initial boot processes from the kernel. These happen to be the same as the old proc numbers, to let user processes reach them with the old numbers, but FS and PM don't know that. All new processes after INIT, even after the generation number wraps around, get endpoint numbers with generation 1 and higher, so the first instances of the boot processes are the only processes ever to have endpoint numbers in the old proc number range. More return code checks of sys_* functions have been added. IS has become endpoint-aware. Ditched the 'text' and 'data' fields in the kernel dump (which show locations, not sizes, so aren't terribly useful) in favour of the endpoint number. Proc number is still visible. Some other dumps (e.g. dmap, rs) show endpoint numbers now too which got the formatting changed. PM reading segments using rw_seg() has changed - it uses other fields in the message now instead of encoding the segment and process number and fd in the fd field. For that it uses _read_pm() and _write_pm() which to _taskcall()s directly in pm/misc.c. PM now sys_exit()s itself on panic(), instead of sys_abort(). RS also talks in endpoints instead of process numbers.
135 lines
4.5 KiB
C
135 lines
4.5 KiB
C
/* Data Store Server.
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* This service implements a little publish/subscribe data store that is
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* crucial for the system's fault tolerance. Components that require state
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* can store it here, for later retrieval, e.g., after a crash and subsequent
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* restart by the reincarnation server.
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*
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* Created:
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* Oct 19, 2005 by Jorrit N. Herder
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*/
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#include "inc.h" /* include master header file */
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/* Allocate space for the global variables. */
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int who_e; /* caller's proc number */
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int callnr; /* system call number */
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int sys_panic; /* flag to indicate system-wide panic */
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extern int errno; /* error number set by system library */
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/* Declare some local functions. */
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FORWARD _PROTOTYPE(void init_server, (int argc, char **argv) );
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FORWARD _PROTOTYPE(void exit_server, (void) );
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FORWARD _PROTOTYPE(void get_work, (message *m_ptr) );
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FORWARD _PROTOTYPE(void reply, (int whom, message *m_ptr) );
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/*===========================================================================*
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* main *
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*===========================================================================*/
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PUBLIC int main(int argc, char **argv)
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{
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/* This is the main routine of this service. The main loop consists of
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* three major activities: getting new work, processing the work, and
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* sending the reply. The loop never terminates, unless a panic occurs.
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*/
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message m;
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int result;
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sigset_t sigset;
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/* Initialize the server, then go to work. */
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init_server(argc, argv);
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/* Main loop - get work and do it, forever. */
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while (TRUE) {
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/* Wait for incoming message, sets 'callnr' and 'who'. */
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get_work(&m);
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switch (callnr) {
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case SYS_SIG:
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sigset = (sigset_t) m.NOTIFY_ARG;
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if (sigismember(&sigset,SIGTERM) || sigismember(&sigset,SIGKSTOP)) {
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exit_server();
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}
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continue;
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case DS_PUBLISH:
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result = do_publish(&m);
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break;
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case DS_RETRIEVE:
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result = do_retrieve(&m);
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break;
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case DS_SUBSCRIBE:
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result = do_subscribe(&m);
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break;
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case GETSYSINFO:
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result = do_getsysinfo(&m);
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break;
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default:
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report("DS","warning, got illegal request from:", m.m_source);
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result = EINVAL;
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}
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/* Finally send reply message, unless disabled. */
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if (result != EDONTREPLY) {
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m.m_type = result; /* build reply message */
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reply(who_e, &m); /* send it away */
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}
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}
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return(OK); /* shouldn't come here */
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}
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/*===========================================================================*
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* init_server *
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*===========================================================================*/
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PRIVATE void init_server(int argc, char **argv)
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{
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/* Initialize the data store server. */
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int i, s;
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struct sigaction sigact;
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/* Install signal handler. Ask PM to transform signal into message. */
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sigact.sa_handler = SIG_MESS;
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sigact.sa_mask = ~0; /* block all other signals */
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sigact.sa_flags = 0; /* default behaviour */
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if (sigaction(SIGTERM, &sigact, NULL) < 0)
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report("DS","warning, sigaction() failed", errno);
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}
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/*===========================================================================*
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* exit_server *
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*===========================================================================*/
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PRIVATE void exit_server()
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{
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/* Shut down the information service. */
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/* Done. Now exit. */
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exit(0);
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}
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/*===========================================================================*
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* get_work *
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*===========================================================================*/
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PRIVATE void get_work(m_ptr)
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message *m_ptr; /* message buffer */
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{
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int status = 0;
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status = receive(ANY, m_ptr); /* this blocks until message arrives */
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if (OK != status)
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panic("DS","failed to receive message!", status);
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who_e = m_ptr->m_source; /* message arrived! set sender */
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callnr = m_ptr->m_type; /* set function call number */
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}
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/*===========================================================================*
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* reply *
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*===========================================================================*/
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PRIVATE void reply(who_e, m_ptr)
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int who_e; /* destination */
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message *m_ptr; /* message buffer */
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{
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int s;
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s = send(who_e, m_ptr); /* send the message */
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if (OK != s)
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panic("DS", "unable to send reply!", s);
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}
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