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minix/servers/pm/main.c
Cristiano Giuffrida 1f5841c8ed Basic System Event Framework (SEF) with ping and live update. 
SYSLIB CHANGES:
- SEF must be used by every system process and is thereby part of the system
library.
- The framework provides a receive() interface (sef_receive) for system
processes to automatically catch known system even messages and process them.
- SEF provides a default behavior for each type of system event, but allows
system processes to register callbacks to override the default behavior.
- Custom (local to the process) or predefined (provided by SEF) callback
implementations can be registered to SEF.
- SEF currently includes support for 2 types of system events:
  1. SEF Ping. The event occurs every time RS sends a ping to figure out
  whether a system process is still alive. The default callback implementation
  provided by SEF is to notify RS back to let it know the process is alive
  and kicking.
  2. SEF Live update. The event occurs every time RS sends a prepare to update
  message to let a system process know an update is available and to prepare
  for it. The live update support is very basic for now. SEF only deals with
  verifying if the prepare state can be supported by the process, dumping the
  state for debugging purposes, and providing an event-driven programming
  model to the process to react to state changes check-in when ready to update.
- SEF should be extended in the future to integrate support for more types of
system events. Ideally, all the cross-cutting concerns should be integrated into
SEF to avoid duplicating code and ease extensibility. Examples include:
  * PM notify messages primarily used at shutdown.
  * SYSTEM notify messages primarily used for signals.
  * CLOCK notify messages used for system alarms.
  * Debug messages. IS could still be in charge of fkey handling but would
  forward the debug message to the target process (e.g. PM, if the user
  requested debug information about PM). SEF would then catch the message and
  do nothing unless the process has registered an appropriate callback to
  deal with the event. This simplifies the programming model to print debug
  information, avoids duplicating code, and reduces the effort to print
  debug information.

SYSTEM PROCESSES CHANGES:
- Every system process registers SEF callbacks it needs to override the default
system behavior and calls sef_startup() right after being started.
- sef_startup() does almost nothing now, but will be extended in the future to
support callbacks of its own to let RS control and synchronize with every
system process at initialization time.
- Every system process calls sef_receive() now rather than receive() directly,
to let SEF handle predefined system events.

RS CHANGES:
- RS supports a basic single-component live update protocol now, as follows:
  * When an update command is issued (via "service update *"), RS notifies the
  target system process to prepare for a specific update state.
  * If the process doesn't respond back in time, the update is aborted.
  * When the process responds back, RS kills it and marks it for refreshing.
  * The process is then automatically restarted as for a buggy process and can
  start running again.
  * Live update is currently prototyped as a controlled failure.
2009-12-21 14:12:21 +00:00

520 lines
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/* This file contains the main program of the process manager and some related
* procedures. When MINIX starts up, the kernel runs for a little while,
* initializing itself and its tasks, and then it runs PM and FS. Both PM
* and FS initialize themselves as far as they can. PM asks the kernel for
* all free memory and starts serving requests.
*
* The entry points into this file are:
* main: starts PM running
* setreply: set the reply to be sent to process making an PM system call
*/
#include "pm.h"
#include <minix/keymap.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/ds.h>
#include <minix/type.h>
#include <minix/endpoint.h>
#include <minix/minlib.h>
#include <minix/type.h>
#include <minix/vm.h>
#include <minix/crtso.h>
#include <signal.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/resource.h>
#include <sys/utsname.h>
#include <string.h>
#include <archconst.h>
#include <archtypes.h>
#include <env.h>
#include "mproc.h"
#include "param.h"
#include "../../kernel/const.h"
#include "../../kernel/config.h"
#include "../../kernel/proc.h"
#if ENABLE_SYSCALL_STATS
EXTERN unsigned long calls_stats[NCALLS];
#endif
FORWARD _PROTOTYPE( void get_work, (void) );
FORWARD _PROTOTYPE( void pm_init, (void) );
FORWARD _PROTOTYPE( int get_nice_value, (int queue) );
FORWARD _PROTOTYPE( void handle_fs_reply, (void) );
#define click_to_round_k(n) \
((unsigned) ((((unsigned long) (n) << CLICK_SHIFT) + 512) / 1024))
/* SEF functions and variables. */
FORWARD _PROTOTYPE( void sef_local_startup, (void) );
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC int main()
{
/* Main routine of the process manager. */
int result, s, proc_nr;
struct mproc *rmp;
sigset_t sigset;
/* SEF local startup. */
sef_local_startup();
pm_init(); /* initialize process manager tables */
/* This is PM's main loop- get work and do it, forever and forever. */
while (TRUE) {
get_work(); /* wait for an PM system call */
/* Drop delayed calls from exiting processes. */
if (mp->mp_flags & EXITING)
continue;
/* Check for system notifications first. Special cases. */
if (is_notify(call_nr)) {
switch(who_p) {
case CLOCK:
pm_expire_timers(m_in.NOTIFY_TIMESTAMP);
result = SUSPEND; /* don't reply */
break;
case SYSTEM: /* signals pending */
sigset = m_in.NOTIFY_ARG;
if (sigismember(&sigset, SIGKSIG)) {
(void) ksig_pending();
}
result = SUSPEND; /* don't reply */
break;
default :
result = ENOSYS;
}
/* done, send reply and continue */
goto send_reply;
}
switch(call_nr)
{
case PM_SETUID_REPLY:
case PM_SETGID_REPLY:
case PM_SETSID_REPLY:
case PM_EXEC_REPLY:
case PM_EXIT_REPLY:
case PM_CORE_REPLY:
case PM_FORK_REPLY:
case PM_FORK_NB_REPLY:
case PM_UNPAUSE_REPLY:
case PM_REBOOT_REPLY:
case PM_SETGROUPS_REPLY:
if (who_e == FS_PROC_NR)
{
handle_fs_reply();
result= SUSPEND; /* don't reply */
}
else
result= ENOSYS;
break;
case ALLOCMEM:
result= do_allocmem();
break;
case FORK_NB:
result= do_fork_nb();
break;
case EXEC_NEWMEM:
result= exec_newmem();
break;
case EXEC_RESTART:
result= do_execrestart();
break;
case PROCSTAT:
result= do_procstat();
break;
case GETPROCNR:
result= do_getprocnr();
break;
case GETEPINFO:
result= do_getepinfo();
break;
default:
/* Else, if the system call number is valid, perform the
* call.
*/
if ((unsigned) call_nr >= NCALLS) {
result = ENOSYS;
} else {
#if ENABLE_SYSCALL_STATS
calls_stats[call_nr]++;
#endif
result = (*call_vec[call_nr])();
}
break;
}
send_reply:
/* Send the results back to the user to indicate completion. */
if (result != SUSPEND) setreply(who_p, result);
/* Send out all pending reply messages, including the answer to
* the call just made above.
*/
for (proc_nr=0, rmp=mproc; proc_nr < NR_PROCS; proc_nr++, rmp++) {
/* In the meantime, the process may have been killed by a
* signal (e.g. if a lethal pending signal was unblocked)
* without the PM realizing it. If the slot is no longer in
* use or the process is exiting, don't try to reply.
*/
if ((rmp->mp_flags & (REPLY | IN_USE | EXITING)) ==
(REPLY | IN_USE)) {
s=sendnb(rmp->mp_endpoint, &rmp->mp_reply);
if (s != OK) {
printf("PM can't reply to %d (%s): %d\n",
rmp->mp_endpoint, rmp->mp_name, s);
}
rmp->mp_flags &= ~REPLY;
}
}
}
return(OK);
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
PRIVATE void sef_local_startup()
{
/* No live update support for now. */
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* get_work *
*===========================================================================*/
PRIVATE void get_work()
{
/* Wait for the next message and extract useful information from it. */
if (sef_receive(ANY, &m_in) != OK)
panic(__FILE__,"PM sef_receive error", NO_NUM);
who_e = m_in.m_source; /* who sent the message */
if(pm_isokendpt(who_e, &who_p) != OK)
panic(__FILE__, "PM got message from invalid endpoint", who_e);
call_nr = m_in.m_type; /* system call number */
/* Process slot of caller. Misuse PM's own process slot if the kernel is
* calling. This can happen in case of synchronous alarms (CLOCK) or or
* event like pending kernel signals (SYSTEM).
*/
mp = &mproc[who_p < 0 ? PM_PROC_NR : who_p];
if(who_p >= 0 && mp->mp_endpoint != who_e) {
panic(__FILE__, "PM endpoint number out of sync with source",
mp->mp_endpoint);
}
}
/*===========================================================================*
* setreply *
*===========================================================================*/
PUBLIC void setreply(proc_nr, result)
int proc_nr; /* process to reply to */
int result; /* result of call (usually OK or error #) */
{
/* Fill in a reply message to be sent later to a user process. System calls
* may occasionally fill in other fields, this is only for the main return
* value, and for setting the "must send reply" flag.
*/
register struct mproc *rmp = &mproc[proc_nr];
if(proc_nr < 0 || proc_nr >= NR_PROCS)
panic(__FILE__,"setreply arg out of range", proc_nr);
rmp->mp_reply.reply_res = result;
rmp->mp_flags |= REPLY; /* reply pending */
}
extern int unmap_ok;
/*===========================================================================*
* pm_init *
*===========================================================================*/
PRIVATE void pm_init()
{
/* Initialize the process manager.
* Memory use info is collected from the boot monitor, the kernel, and
* all processes compiled into the system image. Initially this information
* is put into an array mem_chunks. Elements of mem_chunks are struct memory,
* and hold base, size pairs in units of clicks. This array is small, there
* should be no more than 8 chunks. After the array of chunks has been built
* the contents are used to initialize the hole list. Space for the hole list
* is reserved as an array with twice as many elements as the maximum number
* of processes allowed. It is managed as a linked list, and elements of the
* array are struct hole, which, in addition to storage for a base and size in
* click units also contain space for a link, a pointer to another element.
*/
int s;
static struct boot_image image[NR_BOOT_PROCS];
register struct boot_image *ip;
static char core_sigs[] = { SIGQUIT, SIGILL, SIGTRAP, SIGABRT,
SIGEMT, SIGFPE, SIGBUS, SIGSEGV };
static char ign_sigs[] = { SIGCHLD, SIGWINCH, SIGCONT };
static char mess_sigs[] = { SIGTERM, SIGHUP, SIGABRT, SIGQUIT };
register struct mproc *rmp;
register char *sig_ptr;
message mess;
/* Initialize process table, including timers. */
for (rmp=&mproc[0]; rmp<&mproc[NR_PROCS]; rmp++) {
tmr_inittimer(&rmp->mp_timer);
}
/* Build the set of signals which cause core dumps, and the set of signals
* that are by default ignored.
*/
sigemptyset(&core_sset);
for (sig_ptr = core_sigs; sig_ptr < core_sigs+sizeof(core_sigs); sig_ptr++)
sigaddset(&core_sset, *sig_ptr);
sigemptyset(&ign_sset);
for (sig_ptr = ign_sigs; sig_ptr < ign_sigs+sizeof(ign_sigs); sig_ptr++)
sigaddset(&ign_sset, *sig_ptr);
/* Obtain a copy of the boot monitor parameters and the kernel info struct.
* Parse the list of free memory chunks. This list is what the boot monitor
* reported, but it must be corrected for the kernel and system processes.
*/
if ((s=sys_getmonparams(monitor_params, sizeof(monitor_params))) != OK)
panic(__FILE__,"get monitor params failed",s);
if ((s=sys_getkinfo(&kinfo)) != OK)
panic(__FILE__,"get kernel info failed",s);
/* Initialize PM's process table. Request a copy of the system image table
* that is defined at the kernel level to see which slots to fill in.
*/
if (OK != (s=sys_getimage(image)))
panic(__FILE__,"couldn't get image table: %d\n", s);
procs_in_use = 0; /* start populating table */
for (ip = &image[0]; ip < &image[NR_BOOT_PROCS]; ip++) {
if (ip->proc_nr >= 0) { /* task have negative nrs */
procs_in_use += 1; /* found user process */
/* Set process details found in the image table. */
rmp = &mproc[ip->proc_nr];
strncpy(rmp->mp_name, ip->proc_name, PROC_NAME_LEN);
rmp->mp_nice = get_nice_value(ip->priority);
sigemptyset(&rmp->mp_sig2mess);
sigemptyset(&rmp->mp_ignore);
sigemptyset(&rmp->mp_sigmask);
sigemptyset(&rmp->mp_catch);
if (ip->proc_nr == INIT_PROC_NR) { /* user process */
/* INIT is root, we make it father of itself. This is
* not really OK, INIT should have no father, i.e.
* a father with pid NO_PID. But PM currently assumes
* that mp_parent always points to a valid slot number.
*/
rmp->mp_parent = INIT_PROC_NR;
rmp->mp_procgrp = rmp->mp_pid = INIT_PID;
rmp->mp_flags |= IN_USE;
}
else { /* system process */
if(ip->proc_nr == RS_PROC_NR) {
rmp->mp_parent = INIT_PROC_NR;
}
else {
rmp->mp_parent = RS_PROC_NR;
}
rmp->mp_pid = get_free_pid();
rmp->mp_flags |= IN_USE | PRIV_PROC;
for (sig_ptr = mess_sigs;
sig_ptr < mess_sigs+sizeof(mess_sigs);
sig_ptr++)
sigaddset(&rmp->mp_sig2mess, *sig_ptr);
}
/* Get kernel endpoint identifier. */
rmp->mp_endpoint = ip->endpoint;
/* Tell FS about this system process. */
mess.PR_SLOT = ip->proc_nr;
mess.PR_PID = rmp->mp_pid;
mess.PR_ENDPT = rmp->mp_endpoint;
if (OK != (s=send(FS_PROC_NR, &mess)))
panic(__FILE__,"can't sync up with FS", s);
}
}
/* Override some details for PM. */
sigfillset(&mproc[PM_PROC_NR].mp_ignore); /* guard against signals */
/* Tell FS that no more system processes follow and synchronize. */
mess.PR_ENDPT = NONE;
if (sendrec(FS_PROC_NR, &mess) != OK || mess.m_type != OK)
panic(__FILE__,"can't sync up with FS", NO_NUM);
#if (CHIP == INTEL)
uts_val.machine[0] = 'i';
strcpy(uts_val.machine + 1, itoa(getprocessor()));
#endif
system_hz = sys_hz();
/* Map out our own text and data. This is normally done in crtso.o
* but PM is an exception - we don't get to talk to VM so early on.
* That's why we override munmap() and munmap_text() in utility.c.
*
* _minix_unmapzero() is the same code in crtso.o that normally does
* it on startup. It's best that it's there as crtso.o knows exactly
* what the ranges are of the filler data.
*/
unmap_ok = 1;
_minix_unmapzero();
}
/*===========================================================================*
* get_nice_value *
*===========================================================================*/
PRIVATE int get_nice_value(queue)
int queue; /* store mem chunks here */
{
/* Processes in the boot image have a priority assigned. The PM doesn't know
* about priorities, but uses 'nice' values instead. The priority is between
* MIN_USER_Q and MAX_USER_Q. We have to scale between PRIO_MIN and PRIO_MAX.
*/
int nice_val = (queue - USER_Q) * (PRIO_MAX-PRIO_MIN+1) /
(MIN_USER_Q-MAX_USER_Q+1);
if (nice_val > PRIO_MAX) nice_val = PRIO_MAX; /* shouldn't happen */
if (nice_val < PRIO_MIN) nice_val = PRIO_MIN; /* shouldn't happen */
return nice_val;
}
void checkme(char *str, int line)
{
struct mproc *trmp;
int boned = 0;
int proc_nr;
for (proc_nr=0, trmp=mproc; proc_nr < NR_PROCS; proc_nr++, trmp++) {
if ((trmp->mp_flags & (REPLY | IN_USE | EXITING)) ==
(REPLY | IN_USE)) {
int tp;
if(pm_isokendpt(trmp->mp_endpoint, &tp) != OK) {
printf("PM: %s:%d: reply %d to %s is bogus endpoint %d after call %d by %d\n",
str, line, trmp->mp_reply.m_type,
trmp->mp_name, trmp->mp_endpoint, call_nr, who_e);
boned=1;
}
}
if(boned) panic(__FILE__, "corrupt mp_endpoint?", NO_NUM);
}
}
/*===========================================================================*
* handle_fs_reply *
*===========================================================================*/
PRIVATE void handle_fs_reply()
{
struct mproc *rmp;
endpoint_t proc_e;
int r, proc_n;
/* PM_REBOOT is the only request not associated with a process.
* Handle its reply first.
*/
if (call_nr == PM_REBOOT_REPLY) {
vir_bytes code_addr;
size_t code_size;
/* Ask the kernel to abort. All system services, including
* the PM, will get a HARD_STOP notification. Await the
* notification in the main loop.
*/
code_addr = (vir_bytes) monitor_code;
code_size = strlen(monitor_code) + 1;
sys_abort(abort_flag, PM_PROC_NR, code_addr, code_size);
return;
}
/* Get the process associated with this call */
proc_e = m_in.PM_PROC;
if (pm_isokendpt(proc_e, &proc_n) != OK) {
panic(__FILE__, "handle_fs_reply: got bad endpoint from FS", proc_e);
}
rmp = &mproc[proc_n];
/* Now that FS replied, mark the process as FS-idle again */
if (!(rmp->mp_flags & FS_CALL))
panic(__FILE__, "handle_fs_reply: reply without request", call_nr);
rmp->mp_flags &= ~FS_CALL;
if (rmp->mp_flags & UNPAUSED)
panic(__FILE__, "handle_fs_reply: UNPAUSED set on entry", call_nr);
/* Call-specific handler code */
switch (call_nr) {
case PM_SETUID_REPLY:
case PM_SETGID_REPLY:
case PM_SETGROUPS_REPLY:
/* Wake up the original caller */
setreply(rmp-mproc, OK);
break;
case PM_SETSID_REPLY:
/* Wake up the original caller */
setreply(rmp-mproc, rmp->mp_procgrp);
break;
case PM_EXEC_REPLY:
exec_restart(rmp, m_in.PM_STATUS);
break;
case PM_EXIT_REPLY:
exit_restart(rmp, FALSE /*dump_core*/);
break;
case PM_CORE_REPLY:
if (m_in.PM_STATUS == OK)
rmp->mp_sigstatus |= DUMPED;
exit_restart(rmp, TRUE /*dump_core*/);
break;
case PM_FORK_REPLY:
/* Wake up the newly created process */
setreply(proc_n, OK);
/* Wake up the parent */
setreply(rmp->mp_parent, rmp->mp_pid);
break;
case PM_FORK_NB_REPLY:
/* Nothing to do */
break;
case PM_UNPAUSE_REPLY:
/* Process is now unpaused */
rmp->mp_flags |= UNPAUSED;
break;
default:
panic(__FILE__, "handle_fs_reply: unknown reply code", call_nr);
}
/* Now that the process is idle again, look at pending signals */
if ((rmp->mp_flags & (IN_USE | EXITING)) == IN_USE)
restart_sigs(rmp);
}
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