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minix/servers/rs/request.c
Erik van der Kouwe 23284ee7bd User-space scheduling for system processes
2010-07-01 08:32:33 +00:00

780 lines
21 KiB
C
Executable file
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/*
* Changes:
* Jan 22, 2010: Created (Cristiano Giuffrida)
*/
#include "inc.h"
#include "kernel/proc.h"
FORWARD int check_request(struct rs_start *rs_start);
/*===========================================================================*
* do_up *
*===========================================================================*/
PUBLIC int do_up(m_ptr)
message *m_ptr; /* request message pointer */
{
/* A request was made to start a new system service. */
struct rproc *rp;
struct rprocpub *rpub;
int r;
struct rs_start rs_start;
int noblock;
/* Check if the call can be allowed. */
if((r = check_call_permission(m_ptr->m_source, RS_UP, NULL)) != OK)
return r;
/* Allocate a new system service slot. */
r = alloc_slot(&rp);
if(r != OK) {
printf("RS: do_up: unable to allocate a new slot: %d\n", r);
return r;
}
rpub = rp->r_pub;
/* Copy the request structure. */
r = copy_rs_start(m_ptr->m_source, m_ptr->RS_CMD_ADDR, &rs_start);
if (r != OK) {
return r;
}
r = check_request(&rs_start);
if (r != OK) {
return r;
}
noblock = (rs_start.rss_flags & RSS_NOBLOCK);
/* Initialize the slot as requested. */
r = init_slot(rp, &rs_start, m_ptr->m_source);
if(r != OK) {
printf("RS: do_up: unable to init the new slot: %d\n", r);
return r;
}
/* Check for duplicates */
if(lookup_slot_by_label(rpub->label)) {
printf("RS: service with the same label '%s' already exists\n",
rpub->label);
return EBUSY;
}
if(rpub->dev_nr>0 && lookup_slot_by_dev_nr(rpub->dev_nr)) {
printf("RS: service with the same device number %d already exists\n",
rpub->dev_nr);
return EBUSY;
}
/* All information was gathered. Now try to start the system service. */
r = start_service(rp);
if(r != OK) {
return r;
}
/* Unblock the caller immediately if requested. */
if(noblock) {
return OK;
}
/* Late reply - send a reply when service completes initialization. */
rp->r_flags |= RS_LATEREPLY;
rp->r_caller = m_ptr->m_source;
rp->r_caller_request = RS_UP;
return EDONTREPLY;
}
/*===========================================================================*
* do_down *
*===========================================================================*/
PUBLIC int do_down(message *m_ptr)
{
register struct rproc *rp;
register struct rprocpub *rpub;
int s;
char label[RS_MAX_LABEL_LEN];
/* Copy label. */
s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
m_ptr->RS_CMD_LEN, label, sizeof(label));
if(s != OK) {
return s;
}
/* Lookup slot by label. */
rp = lookup_slot_by_label(label);
if(!rp) {
if(rs_verbose)
printf("RS: do_down: service '%s' not found\n", label);
return(ESRCH);
}
rpub = rp->r_pub;
/* Check if the call can be allowed. */
if((s = check_call_permission(m_ptr->m_source, RS_DOWN, rp)) != OK)
return s;
/* Stop service. */
if (rp->r_flags & RS_TERMINATED) {
/* A recovery script is requesting us to bring down the service.
* The service is already gone, simply perform cleanup.
*/
if(rs_verbose)
printf("RS: recovery script performs service down...\n");
unpublish_service(rp);
cleanup_service(rp);
return(OK);
}
stop_service(rp,RS_EXITING);
/* Late reply - send a reply when service dies. */
rp->r_flags |= RS_LATEREPLY;
rp->r_caller = m_ptr->m_source;
rp->r_caller_request = RS_DOWN;
return EDONTREPLY;
}
/*===========================================================================*
* do_restart *
*===========================================================================*/
PUBLIC int do_restart(message *m_ptr)
{
struct rproc *rp;
int s, r;
char label[RS_MAX_LABEL_LEN];
char script[MAX_SCRIPT_LEN];
/* Copy label. */
s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
m_ptr->RS_CMD_LEN, label, sizeof(label));
if(s != OK) {
return s;
}
/* Lookup slot by label. */
rp = lookup_slot_by_label(label);
if(!rp) {
if(rs_verbose)
printf("RS: do_restart: service '%s' not found\n", label);
return(ESRCH);
}
/* Check if the call can be allowed. */
if((r = check_call_permission(m_ptr->m_source, RS_RESTART, rp)) != OK)
return r;
/* We can only be asked to restart a service from a recovery script. */
if (! (rp->r_flags & RS_TERMINATED) ) {
if(rs_verbose)
printf("RS: %s is still running\n", srv_to_string(rp));
return EBUSY;
}
if(rs_verbose)
printf("RS: recovery script performs service restart...\n");
/* Restart the service, but make sure we don't call the script again. */
strcpy(script, rp->r_script);
rp->r_script[0] = '\0';
restart_service(rp);
strcpy(rp->r_script, script);
return OK;
}
/*===========================================================================*
* do_clone *
*===========================================================================*/
PUBLIC int do_clone(message *m_ptr)
{
struct rproc *rp;
struct rprocpub *rpub;
int s, r;
char label[RS_MAX_LABEL_LEN];
char script[MAX_SCRIPT_LEN];
/* Copy label. */
s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
m_ptr->RS_CMD_LEN, label, sizeof(label));
if(s != OK) {
return s;
}
/* Lookup slot by label. */
rp = lookup_slot_by_label(label);
if(!rp) {
if(rs_verbose)
printf("RS: do_clone: service '%s' not found\n", label);
return(ESRCH);
}
rpub = rp->r_pub;
/* Check if the call can be allowed. */
if((r = check_call_permission(m_ptr->m_source, RS_CLONE, rp)) != OK)
return r;
/* Don't clone if a replica is already available. */
if(rp->r_next_rp) {
return EEXIST;
}
/* Clone the service as requested. */
rpub->sys_flags |= SF_USE_REPL;
if ((r = clone_service(rp)) != OK) {
rpub->sys_flags &= ~SF_USE_REPL;
return r;
}
return OK;
}
/*===========================================================================*
* do_refresh *
*===========================================================================*/
PUBLIC int do_refresh(message *m_ptr)
{
register struct rproc *rp;
register struct rprocpub *rpub;
int s;
char label[RS_MAX_LABEL_LEN];
/* Copy label. */
s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
m_ptr->RS_CMD_LEN, label, sizeof(label));
if(s != OK) {
return s;
}
/* Lookup slot by label. */
rp = lookup_slot_by_label(label);
if(!rp) {
if(rs_verbose)
printf("RS: do_refresh: service '%s' not found\n", label);
return(ESRCH);
}
rpub = rp->r_pub;
/* Check if the call can be allowed. */
if((s = check_call_permission(m_ptr->m_source, RS_REFRESH, rp)) != OK)
return s;
/* Refresh service. */
if(rs_verbose)
printf("RS: %s refreshing\n", srv_to_string(rp));
stop_service(rp,RS_REFRESHING);
return OK;
}
/*===========================================================================*
* do_shutdown *
*===========================================================================*/
PUBLIC int do_shutdown(message *m_ptr)
{
int slot_nr;
struct rproc *rp;
int r;
/* Check if the call can be allowed. */
if (m_ptr != NULL) {
if((r = check_call_permission(m_ptr->m_source, RS_SHUTDOWN, NULL)) != OK)
return r;
}
if(rs_verbose)
printf("RS: shutting down...\n");
/* Set flag to tell RS we are shutting down. */
shutting_down = TRUE;
/* Don't restart dead services. */
for (slot_nr = 0; slot_nr < NR_SYS_PROCS; slot_nr++) {
rp = &rproc[slot_nr];
if (rp->r_flags & RS_IN_USE) {
rp->r_flags |= RS_EXITING;
}
}
return(OK);
}
/*===========================================================================*
* do_init_ready *
*===========================================================================*/
PUBLIC int do_init_ready(message *m_ptr)
{
int who_p;
struct rproc *rp;
struct rprocpub *rpub;
int result;
int r;
who_p = _ENDPOINT_P(m_ptr->m_source);
rp = rproc_ptr[who_p];
rpub = rp->r_pub;
result = m_ptr->RS_INIT_RESULT;
/* Make sure the originating service was requested to initialize. */
if(! (rp->r_flags & RS_INITIALIZING) ) {
if(rs_verbose)
printf("RS: do_init_ready: got unexpected init ready msg from %d\n",
m_ptr->m_source);
return(EDONTREPLY);
}
/* Check if something went wrong and the service failed to init.
* In that case, kill the service.
*/
if(result != OK) {
if(rs_verbose)
printf("RS: %s initialization error: %s\n", srv_to_string(rp),
init_strerror(result));
crash_service(rp); /* simulate crash */
return(EDONTREPLY);
}
/* Mark the slot as no longer initializing. */
rp->r_flags &= ~RS_INITIALIZING;
rp->r_check_tm = 0;
getuptime(&rp->r_alive_tm);
/* See if a late reply has to be sent. */
late_reply(rp, OK);
if(rs_verbose)
printf("RS: %s initialized\n", srv_to_string(rp));
/* If the service has completed initialization after a live
* update, end the update now.
*/
if(rp->r_flags & RS_UPDATING) {
printf("RS: update succeeded\n");
end_update(OK);
}
/* If the service has completed initialization after a crash
* make the new instance active and cleanup the old replica.
*/
if(rp->r_prev_rp) {
cleanup_service(rp->r_prev_rp);
rp->r_prev_rp = NULL;
if(rs_verbose)
printf("RS: %s completed restart\n", srv_to_string(rp));
}
/* If we must keep a replica of this system service, create it now. */
if(rpub->sys_flags & SF_USE_REPL) {
if ((r = clone_service(rp)) != OK) {
printf("RS: warning: unable to clone %s\n", srv_to_string(rp));
}
}
return(OK);
}
/*===========================================================================*
* do_update *
*===========================================================================*/
PUBLIC int do_update(message *m_ptr)
{
struct rproc *rp;
struct rproc *new_rp;
struct rprocpub *rpub;
struct rs_start rs_start;
int noblock;
int s;
char label[RS_MAX_LABEL_LEN];
int lu_state;
int prepare_maxtime;
/* Copy the request structure. */
s = copy_rs_start(m_ptr->m_source, m_ptr->RS_CMD_ADDR, &rs_start);
if (s != OK) {
return s;
}
noblock = (rs_start.rss_flags & RSS_NOBLOCK);
s = check_request(&rs_start);
if (s != OK) {
return s;
}
/* Copy label. */
s = copy_label(m_ptr->m_source, rs_start.rss_label.l_addr,
rs_start.rss_label.l_len, label, sizeof(label));
if(s != OK) {
return s;
}
/* Lookup slot by label. */
rp = lookup_slot_by_label(label);
if(!rp) {
if(rs_verbose)
printf("RS: do_update: service '%s' not found\n", label);
return ESRCH;
}
rpub = rp->r_pub;
/* Check if the call can be allowed. */
if((s = check_call_permission(m_ptr->m_source, RS_UPDATE, rp)) != OK)
return s;
/* Retrieve live update state. */
lu_state = m_ptr->RS_LU_STATE;
if(lu_state == SEF_LU_STATE_NULL) {
return(EINVAL);
}
/* Retrieve prepare max time. */
prepare_maxtime = m_ptr->RS_LU_PREPARE_MAXTIME;
if(prepare_maxtime) {
if(prepare_maxtime < 0 || prepare_maxtime > RS_MAX_PREPARE_MAXTIME) {
return(EINVAL);
}
}
else {
prepare_maxtime = RS_DEFAULT_PREPARE_MAXTIME;
}
/* Make sure we are not already updating. */
if(rupdate.flags & RS_UPDATING) {
if(rs_verbose)
printf("RS: do_update: an update is already in progress\n");
return EBUSY;
}
/* Allocate a system service slot for the new version. */
s = alloc_slot(&new_rp);
if(s != OK) {
printf("RS: do_update: unable to allocate a new slot: %d\n", s);
return s;
}
/* Initialize the slot as requested. */
s = init_slot(new_rp, &rs_start, m_ptr->m_source);
if(s != OK) {
printf("RS: do_update: unable to init the new slot: %d\n", s);
return s;
}
/* Let the new version inherit defaults from the old one. */
inherit_service_defaults(rp, new_rp);
/* Create new version of the service but don't let it run. */
s = create_service(new_rp);
if(s != OK) {
printf("RS: do_update: unable to create a new service: %d\n", s);
return s;
}
/* Link old version to new version and mark both as updating. */
rp->r_new_rp = new_rp;
new_rp->r_old_rp = rp;
rp->r_flags |= RS_UPDATING;
rp->r_new_rp->r_flags |= RS_UPDATING;
rupdate.flags |= RS_UPDATING;
getuptime(&rupdate.prepare_tm);
rupdate.prepare_maxtime = prepare_maxtime;
rupdate.rp = rp;
if(rs_verbose)
printf("RS: %s updating\n", srv_to_string(rp));
/* Request to update. */
m_ptr->m_type = RS_LU_PREPARE;
asynsend3(rpub->endpoint, m_ptr, AMF_NOREPLY);
/* Unblock the caller immediately if requested. */
if(noblock) {
return OK;
}
/* Late reply - send a reply when the new version completes initialization. */
rp->r_flags |= RS_LATEREPLY;
rp->r_caller = m_ptr->m_source;
rp->r_caller_request = RS_UPDATE;
return EDONTREPLY;
}
/*===========================================================================*
* do_upd_ready *
*===========================================================================*/
PUBLIC int do_upd_ready(message *m_ptr)
{
struct rproc *rp, *old_rp, *new_rp;
int who_p;
int result;
int r;
who_p = _ENDPOINT_P(m_ptr->m_source);
rp = rproc_ptr[who_p];
result = m_ptr->RS_LU_RESULT;
/* Make sure the originating service was requested to prepare for update. */
if(rp != rupdate.rp) {
if(rs_verbose)
printf("RS: do_upd_ready: got unexpected update ready msg from %d\n",
m_ptr->m_source);
return(EINVAL);
}
/* Check if something went wrong and the service failed to prepare
* for the update. In that case, end the update process. The old version will
* be replied to and continue executing.
*/
if(result != OK) {
end_update(result);
printf("RS: update failed: %s\n", lu_strerror(result));
return OK;
}
/* Perform the update. */
old_rp = rp;
new_rp = rp->r_new_rp;
r = update_service(&old_rp, &new_rp);
if(r != OK) {
end_update(r);
printf("RS: update failed: error %d\n", r);
return r;
}
/* Let the new version run. */
r = run_service(new_rp, SEF_INIT_LU);
if(r != OK) {
update_service(&new_rp, &old_rp); /* rollback, can't fail. */
end_update(r);
printf("RS: update failed: error %d\n", r);
return r;
}
return(EDONTREPLY);
}
/*===========================================================================*
* do_period *
*===========================================================================*/
PUBLIC void do_period(m_ptr)
message *m_ptr;
{
register struct rproc *rp;
register struct rprocpub *rpub;
clock_t now = m_ptr->NOTIFY_TIMESTAMP;
int s;
long period;
/* If an update is in progress, check its status. */
if(rupdate.flags & RS_UPDATING) {
update_period(m_ptr);
}
/* Search system services table. Only check slots that are in use and not
* updating.
*/
for (rp=BEG_RPROC_ADDR; rp<END_RPROC_ADDR; rp++) {
rpub = rp->r_pub;
if ((rp->r_flags & RS_ACTIVE) && !(rp->r_flags & RS_UPDATING)) {
/* Compute period. */
period = rpub->period;
if(rp->r_flags & RS_INITIALIZING) {
period = RS_INIT_T;
}
/* If the service is to be revived (because it repeatedly exited,
* and was not directly restarted), the binary backoff field is
* greater than zero.
*/
if (rp->r_backoff > 0) {
rp->r_backoff -= 1;
if (rp->r_backoff == 0) {
restart_service(rp);
}
}
/* If the service was signaled with a SIGTERM and fails to respond,
* kill the system service with a SIGKILL signal.
*/
else if (rp->r_stop_tm > 0 && now - rp->r_stop_tm > 2*RS_DELTA_T
&& rp->r_pid > 0) {
crash_service(rp); /* simulate crash */
rp->r_stop_tm = 0;
}
/* There seems to be no special conditions. If the service has a
* period assigned check its status.
*/
else if (period > 0) {
/* Check if an answer to a status request is still pending. If
* the service didn't respond within time, kill it to simulate
* a crash. The failure will be detected and the service will
* be restarted automatically.
*/
if (rp->r_alive_tm < rp->r_check_tm) {
if (now - rp->r_alive_tm > 2*period &&
rp->r_pid > 0 && !(rp->r_flags & RS_NOPINGREPLY)) {
if(rs_verbose)
printf("RS: %s reported late\n",
srv_to_string(rp));
rp->r_flags |= RS_NOPINGREPLY;
crash_service(rp); /* simulate crash */
}
}
/* No answer pending. Check if a period expired since the last
* check and, if so request the system service's status.
*/
else if (now - rp->r_check_tm > rpub->period) {
notify(rpub->endpoint); /* request status */
rp->r_check_tm = now; /* mark time */
}
}
}
}
/* Reschedule a synchronous alarm for the next period. */
if (OK != (s=sys_setalarm(RS_DELTA_T, 0)))
panic("couldn't set alarm: %d", s);
}
/*===========================================================================*
* do_sigchld *
*===========================================================================*/
PUBLIC void do_sigchld()
{
/* PM informed us that there are dead children to cleanup. Go get them. */
pid_t pid;
int status;
struct rproc *rp;
struct rproc **rps;
struct rprocpub *rpub;
int i, nr_rps;
if(rs_verbose)
printf("RS: got SIGCHLD signal, cleaning up dead children\n");
while ( (pid = waitpid(-1, &status, WNOHANG)) != 0 ) {
rp = lookup_slot_by_pid(pid);
if(rp != NULL) {
rpub = rp->r_pub;
if(rs_verbose)
printf("RS: %s exited via another signal manager\n",
srv_to_string(rp));
/* The slot is still there. This means RS is not the signal
* manager assigned to the process. Ignore the event but
* free slots for all the service instances and send a late
* reply if necessary.
*/
get_service_instances(rp, &rps, &nr_rps);
for(i=0;i<nr_rps;i++) {
if(rupdate.flags & RS_UPDATING) {
rupdate.flags &= ~RS_UPDATING;
}
free_slot(rps[i]);
}
}
}
}
/*===========================================================================*
* do_getsysinfo *
*===========================================================================*/
PUBLIC int do_getsysinfo(m_ptr)
message *m_ptr;
{
vir_bytes src_addr, dst_addr;
int dst_proc;
size_t len;
int s;
/* Check if the call can be allowed. */
if((s = check_call_permission(m_ptr->m_source, 0, NULL)) != OK)
return s;
switch(m_ptr->m1_i1) {
case SI_PROC_TAB:
src_addr = (vir_bytes) rproc;
len = sizeof(struct rproc) * NR_SYS_PROCS;
break;
case SI_PROCPUB_TAB:
src_addr = (vir_bytes) rprocpub;
len = sizeof(struct rprocpub) * NR_SYS_PROCS;
break;
default:
return(EINVAL);
}
dst_proc = m_ptr->m_source;
dst_addr = (vir_bytes) m_ptr->m1_p1;
if (OK != (s=sys_datacopy(SELF, src_addr, dst_proc, dst_addr, len)))
return(s);
return(OK);
}
/*===========================================================================*
* do_lookup *
*===========================================================================*/
PUBLIC int do_lookup(m_ptr)
message *m_ptr;
{
static char namebuf[100];
int len, r;
struct rproc *rrp;
struct rprocpub *rrpub;
len = m_ptr->RS_NAME_LEN;
if(len < 2 || len >= sizeof(namebuf)) {
printf("RS: len too weird (%d)\n", len);
return EINVAL;
}
if((r=sys_vircopy(m_ptr->m_source, D, (vir_bytes) m_ptr->RS_NAME,
SELF, D, (vir_bytes) namebuf, len)) != OK) {
printf("RS: name copy failed\n");
return r;
}
namebuf[len] = '\0';
rrp = lookup_slot_by_label(namebuf);
if(!rrp) {
return ESRCH;
}
rrpub = rrp->r_pub;
m_ptr->RS_ENDPOINT = rrpub->endpoint;
return OK;
}
/*===========================================================================*
* check_request *
*===========================================================================*/
PRIVATE int check_request(struct rs_start *rs_start)
{
/* Verify scheduling parameters */
if (rs_start->rss_scheduler != KERNEL &&
(rs_start->rss_scheduler < 0 ||
rs_start->rss_scheduler > LAST_SPECIAL_PROC_NR)) {
printf("RS: check_request: invalid scheduler %d\n",
rs_start->rss_scheduler);
return EINVAL;
}
if (rs_start->rss_priority >= NR_SCHED_QUEUES) {
printf("RS: check_request: priority %u out of range\n",
rs_start->rss_priority);
return EINVAL;
}
if (rs_start->rss_quantum <= 0) {
printf("RS: check_request: quantum %u out of range\n",
rs_start->rss_quantum);
return EINVAL;
}
return OK;
}
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