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minix/servers/pm/main.c
David van Moolenbroek 1a9e07b0e5 PM: fix ptrace(T_EXIT) 'exit_proc: not idle' race condition.
2009-07-11 13:22:56 +00:00

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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 <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 send_work, (void) );
FORWARD _PROTOTYPE( void handle_fs_reply, (message *m_ptr) );
FORWARD _PROTOTYPE( void restart_sigs, (struct mproc *rmp) );
#define click_to_round_k(n) \
((unsigned) ((((unsigned long) (n) << CLICK_SHIFT) + 512) / 1024))
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC int main()
{
/* Main routine of the process manager. */
int result, s, proc_nr;
struct mproc *rmp;
sigset_t sigset;
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 */
/* Check for system notifications first. Special cases. */
switch(call_nr)
{
case SYN_ALARM:
pm_expire_timers(m_in.NOTIFY_TIMESTAMP);
result = SUSPEND; /* don't reply */
break;
case SYS_SIG: /* signals pending */
sigset = m_in.NOTIFY_ARG;
if (sigismember(&sigset, SIGKSIG)) {
(void) ksig_pending();
}
result = SUSPEND; /* don't reply */
break;
case PM_GET_WORK:
if (who_e == FS_PROC_NR)
{
send_work();
result= SUSPEND; /* don't reply */
}
else
result= ENOSYS;
break;
case PM_EXIT_REPLY:
case PM_REBOOT_REPLY:
case PM_EXEC_REPLY:
case PM_CORE_REPLY:
if (who_e == FS_PROC_NR)
{
handle_fs_reply(&m_in);
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 GETPUID:
result= do_getpuid();
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 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);
}
/*===========================================================================*
* get_work *
*===========================================================================*/
PRIVATE void get_work()
{
/* Wait for the next message and extract useful information from it. */
if (receive(ANY, &m_in) != OK)
panic(__FILE__,"PM 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 */
}
/*===========================================================================*
* pm_init *
*===========================================================================*/
PRIVATE void pm_init()
{
int failed = 0;
int f = 0;
/* 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, SIGUSR1, SIGSEGV, SIGUSR2 };
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);
rmp->mp_fs_call= PM_IDLE;
rmp->mp_fs_call2= PM_IDLE;
}
/* 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);
#if 0
rmp->mp_parent = RS_PROC_NR;
#endif
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 */
rmp->mp_procgrp = rmp->mp_pid = INIT_PID;
rmp->mp_flags |= IN_USE;
}
else { /* system process */
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);
/* Register proces with ds */
s= ds_publish_u32(rmp->mp_name, rmp->mp_endpoint);
if (s != OK)
failed++;
}
}
if(failed > 0)
printf("PM: failed to register %d/%d boot processes\n",
failed, NR_BOOT_PROCS);
/* Override some details. INIT, PM, FS and RS are somewhat special. */
mproc[PM_PROC_NR].mp_pid = PM_PID; /* PM has magic pid */
#if 0
mproc[RS_PROC_NR].mp_parent = INIT_PROC_NR; /* INIT is root */
#endif
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
if(f > 0) printf("PM: failed to register %d processes with DS.\n", f);
system_hz = sys_hz();
}
/*===========================================================================*
* 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);
}
}
/*===========================================================================*
* send_work *
*===========================================================================*/
PRIVATE void send_work()
{
int r, call;
struct mproc *rmp;
message m;
m.m_type= PM_IDLE;
for (rmp= mproc; rmp < &mproc[NR_PROCS]; rmp++)
{
call= rmp->mp_fs_call;
if (call == PM_IDLE)
call= rmp->mp_fs_call2;
if (call == PM_IDLE)
continue;
switch(call)
{
case PM_SETSID:
m.m_type= call;
m.PM_SETSID_PROC= rmp->mp_endpoint;
/* FS does not reply */
rmp->mp_fs_call= PM_IDLE;
/* Wakeup the original caller */
setreply(rmp-mproc, rmp->mp_procgrp);
break;
case PM_SETGID:
m.m_type= call;
m.PM_SETGID_PROC= rmp->mp_endpoint;
m.PM_SETGID_EGID= rmp->mp_effgid;
m.PM_SETGID_RGID= rmp->mp_realgid;
/* FS does not reply */
rmp->mp_fs_call= PM_IDLE;
/* Wakeup the original caller */
setreply(rmp-mproc, OK);
break;
case PM_SETUID:
m.m_type= call;
m.PM_SETUID_PROC= rmp->mp_endpoint;
m.PM_SETUID_EGID= rmp->mp_effuid;
m.PM_SETUID_RGID= rmp->mp_realuid;
/* FS does not reply */
rmp->mp_fs_call= PM_IDLE;
/* Wakeup the original caller */
setreply(rmp-mproc, OK);
break;
case PM_FORK:
{
int parent_p;
struct mproc *parent_mp;
parent_p = rmp->mp_parent;
parent_mp = &mproc[parent_p];
m.m_type= call;
m.PM_FORK_PPROC= parent_mp->mp_endpoint;
m.PM_FORK_CPROC= rmp->mp_endpoint;
m.PM_FORK_CPID= rmp->mp_pid;
/* FS does not reply */
rmp->mp_fs_call= PM_IDLE;
/* Wakeup the newly created process */
setreply(rmp-mproc, OK);
/* Wakeup the parent */
setreply(parent_mp-mproc, rmp->mp_pid);
break;
}
case PM_EXIT:
m.m_type= call;
m.PM_EXIT_PROC= rmp->mp_endpoint;
/* Mark the process as busy */
rmp->mp_fs_call= PM_BUSY;
break;
case PM_UNPAUSE:
m.m_type= call;
m.PM_UNPAUSE_PROC= rmp->mp_endpoint;
/* FS does not reply */
rmp->mp_fs_call2= PM_IDLE;
/* Ask the kernel to deliver the signal */
r= sys_sigsend(rmp->mp_endpoint,
&rmp->mp_sigmsg);
if (r != OK) {
#if 0
panic(__FILE__,"sys_sigsend failed",r);
#else
printf("PM: PM_UNPAUSE: sys_sigsend failed to %d: %d\n",
rmp->mp_endpoint, r);
#endif
}
break;
case PM_UNPAUSE_TR:
m.m_type= call;
m.PM_UNPAUSE_PROC= rmp->mp_endpoint;
/* FS does not reply */
rmp->mp_fs_call= PM_IDLE;
break;
case PM_EXEC:
m.m_type= call;
m.PM_EXEC_PROC= rmp->mp_endpoint;
m.PM_EXEC_PATH= rmp->mp_exec_path;
m.PM_EXEC_PATH_LEN= rmp->mp_exec_path_len;
m.PM_EXEC_FRAME= rmp->mp_exec_frame;
m.PM_EXEC_FRAME_LEN= rmp->mp_exec_frame_len;
/* Mark the process as busy */
rmp->mp_fs_call= PM_BUSY;
break;
case PM_FORK_NB:
{
int parent_p;
struct mproc *parent_mp;
parent_p = rmp->mp_parent;
parent_mp = &mproc[parent_p];
m.m_type= PM_FORK;
m.PM_FORK_PPROC= parent_mp->mp_endpoint;
m.PM_FORK_CPROC= rmp->mp_endpoint;
m.PM_FORK_CPID= rmp->mp_pid;
/* FS does not reply */
rmp->mp_fs_call= PM_IDLE;
break;
}
case PM_DUMPCORE:
m.m_type= call;
m.PM_CORE_PROC= rmp->mp_endpoint;
/* XXX
m.PM_CORE_SEGPTR= (char *)rmp->mp_seg;
*/
/* Mark the process as busy */
rmp->mp_fs_call= PM_BUSY;
break;
default:
printf("send_work: should report call 0x%x to FS\n",
call);
break;
}
break;
}
if (m.m_type != PM_IDLE)
{
restart_sigs(rmp);
}
else if (report_reboot)
{
m.m_type= PM_REBOOT;
report_reboot= FALSE;
}
r= send(FS_PROC_NR, &m);
if (r != OK) panic("pm", "send_work: send failed", r);
}
/*===========================================================================*
* handle_fs_reply *
*===========================================================================*/
PRIVATE void handle_fs_reply(m_ptr)
message *m_ptr;
{
int r, proc_e, proc_n, s;
struct mproc *rmp;
switch(m_ptr->m_type)
{
case PM_EXIT_REPLY:
proc_e= m_ptr->PM_EXIT_PROC;
if (pm_isokendpt(proc_e, &proc_n) != OK)
{
panic(__FILE__,
"PM_EXIT_REPLY: got bad endpoint from FS",
proc_e);
}
rmp= &mproc[proc_n];
/* Call is finished */
rmp->mp_fs_call= PM_IDLE;
exit_restart(rmp, FALSE /*dump_core*/);
break;
case 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);
break;
}
case PM_EXEC_REPLY:
proc_e= m_ptr->PM_EXEC_PROC;
if (pm_isokendpt(proc_e, &proc_n) != OK)
{
panic(__FILE__,
"PM_EXIT_REPLY: got bad endpoint from FS",
proc_e);
}
rmp= &mproc[proc_n];
/* Call is finished */
rmp->mp_fs_call= PM_IDLE;
exec_restart(rmp, m_ptr->PM_EXEC_STATUS);
restart_sigs(rmp);
break;
case PM_CORE_REPLY:
{
proc_e= m_ptr->PM_CORE_PROC;
if (pm_isokendpt(proc_e, &proc_n) != OK)
{
panic(__FILE__,
"PM_EXIT_REPLY: got bad endpoint from FS",
proc_e);
}
rmp= &mproc[proc_n];
if (m_ptr->PM_CORE_STATUS == OK)
rmp->mp_sigstatus |= DUMPED;
/* Call is finished */
rmp->mp_fs_call= PM_IDLE;
exit_restart(rmp, TRUE /*dump_core*/);
break;
}
default:
panic(__FILE__, "handle_fs_reply: unknown reply type",
m_ptr->m_type);
break;
}
}
/*===========================================================================*
* restart_sigs *
*===========================================================================*/
PRIVATE void restart_sigs(rmp)
struct mproc *rmp;
{
if (rmp->mp_fs_call != PM_IDLE || rmp->mp_fs_call2 != PM_IDLE)
return;
if (rmp->mp_flags & TRACE_EXIT) {
exit_proc(rmp, rmp->mp_exitstatus, FALSE /*dump_core*/);
}
else if (rmp->mp_flags & PM_SIG_PENDING) {
rmp->mp_flags &= ~PM_SIG_PENDING;
check_pending(rmp);
if (!(rmp->mp_flags & PM_SIG_PENDING)) {
/* Allow the process to be scheduled */
sys_nice(rmp->mp_endpoint, rmp->mp_nice);
}
}
}
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