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minix/servers/pm/misc.c
Tomas Hruby b09bcf6779 Scheduling server (by Bjorn Swift) 
In this second phase, scheduling is moved from PM to its own
scheduler (see r6557 for phase one). In the next phase we hope to a)
include useful information in the "out of quantum" message and b)
create some simple scheduling policy that makes use of that
information.

When the system starts up, PM will iterate over its process table and
ask SCHED to take over scheduling unprivileged processes. This is
done by sending a SCHEDULING_START message to SCHED. This message
includes the processes endpoint, the parent's endpoint and its nice
level. The scheduler adds this process to its schedproc table, issues
a schedctl, and returns its own endpoint to PM - as the endpoint of
the effective scheduler. When a process terminates, a SCHEDULING_STOP
message is sent to the scheduler.

The reason for this effective endpoint is for future compatibility.
Some day, we may have a scheduler that, instead of scheduling the
process itself, forwards the SCHEDULING_START message on to another
scheduler.

PM has information on who schedules whom. As such, scheduling
messages from user-land are sent through PM. An example is when
processes change their priority, using nice(). In that case, a
getsetpriority message is sent to PM, which then sends a
SCHEDULING_SET_NICE to the process's effective scheduler.

When a process is forked through PM, it inherits its parent's
scheduler, but is spawned with an empty quantum. As before, a request
to fork a process flows through VM before returning to PM, which then
wakes up the child process. This flow has been modified slightly so
that PM notifies the scheduler of the new process, before waking up
the child process. If the scheduler fails to take over scheduling,
the child process is torn down and the fork fails with an erroneous
value.

Process priority is entirely decided upon using nice levels. PM
stores a copy of each process's nice level and when a child is
forked, its parent's nice level is sent in the SCHEDULING_START
message. How this level is mapped to a priority queue is up to the
scheduler. It should be noted that the nice level is used to
determine the max_priority and the parent could have been in a lower
priority when it was spawned. To prevent a CPU intensive process from
hawking the CPU by continuously forking children that get scheduled
in the max_priority, the scheduler should determine in which queue
the parent is currently scheduled, and schedule the child in that
same queue.

Other fixes: The USER_Q in kernel/proc.h was incorrectly defined as
NR_SCHED_QUEUES/2. That results in a "off by one" error when
converting priority->nice->priority for nice=0. This also had the
side effect that if someone were to set the MAX_USER_Q to something
else than 0, then USER_Q would be off.
2010-05-18 13:39:04 +00:00

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/* Miscellaneous system calls. Author: Kees J. Bot
* 31 Mar 2000
* The entry points into this file are:
* do_reboot: kill all processes, then reboot system
* do_procstat: request process status (Jorrit N. Herder)
* do_getsysinfo: request copy of PM data structure (Jorrit N. Herder)
* do_getprocnr: lookup process slot number (Jorrit N. Herder)
* do_getepinfo: get the pid/uid/gid of a process given its endpoint
* do_getsetpriority: get/set process priority
* do_svrctl: process manager control
*/
#define brk _brk
#include "pm.h"
#include <minix/callnr.h>
#include <signal.h>
#include <sys/svrctl.h>
#include <sys/resource.h>
#include <sys/utsname.h>
#include <minix/com.h>
#include <minix/config.h>
#include <minix/sysinfo.h>
#include <minix/type.h>
#include <minix/vm.h>
#include <string.h>
#include <machine/archtypes.h>
#include <lib.h>
#include <assert.h>
#include "mproc.h"
#include "param.h"
#include "kernel/proc.h"
PUBLIC struct utsname uts_val = {
"Minix", /* system name */
"noname", /* node/network name */
OS_RELEASE, /* O.S. release (e.g. 1.5) */
OS_VERSION, /* O.S. version (e.g. 10) */
"xyzzy", /* machine (cpu) type (filled in later) */
#if __i386
"i386", /* architecture */
#else
#error /* oops, no 'uname -mk' */
#endif
};
PRIVATE char *uts_tbl[] = {
uts_val.arch,
NULL, /* No kernel architecture */
uts_val.machine,
NULL, /* No hostname */
uts_val.nodename,
uts_val.release,
uts_val.version,
uts_val.sysname,
NULL, /* No bus */ /* No bus */
};
#if ENABLE_SYSCALL_STATS
PUBLIC unsigned long calls_stats[NCALLS];
#endif
FORWARD _PROTOTYPE( int getpciinfo, (struct pciinfo *pciinfo) );
/*===========================================================================*
* do_procstat *
*===========================================================================*/
PUBLIC int do_procstat()
{
/* For the moment, this is only used to return pending signals to
* system processes that request the PM for their own status.
*
* Future use might include the FS requesting for process status of
* any user process.
*/
/* This call should be removed, or made more general. */
if (m_in.stat_nr == SELF) {
mp->mp_reply.sig_set = mp->mp_sigpending;
sigemptyset(&mp->mp_sigpending);
}
else {
return(ENOSYS);
}
return(OK);
}
/*===========================================================================*
* do_sysuname *
*===========================================================================*/
PUBLIC int do_sysuname()
{
/* Set or get uname strings. */
int r;
size_t n;
char *string;
#if 0 /* for updates */
char tmp[sizeof(uts_val.nodename)];
static short sizes[] = {
0, /* arch, (0 = read-only) */
0, /* kernel */
0, /* machine */
0, /* sizeof(uts_val.hostname), */
sizeof(uts_val.nodename),
0, /* release */
0, /* version */
0, /* sysname */
};
#endif
if ((unsigned) m_in.sysuname_field >= _UTS_MAX) return(EINVAL);
string = uts_tbl[m_in.sysuname_field];
if (string == NULL)
return EINVAL; /* Unsupported field */
switch (m_in.sysuname_req) {
case _UTS_GET:
/* Copy an uname string to the user. */
n = strlen(string) + 1;
if (n > m_in.sysuname_len) n = m_in.sysuname_len;
r = sys_vircopy(SELF, D, (phys_bytes) string,
mp->mp_endpoint, D, (phys_bytes) m_in.sysuname_value,
(phys_bytes) n);
if (r < 0) return(r);
break;
#if 0 /* no updates yet */
case _UTS_SET:
/* Set an uname string, needs root power. */
len = sizes[m_in.sysuname_field];
if (mp->mp_effuid != 0 || len == 0) return(EPERM);
n = len < m_in.sysuname_len ? len : m_in.sysuname_len;
if (n <= 0) return(EINVAL);
r = sys_vircopy(mp->mp_endpoint, D, (phys_bytes) m_in.sysuname_value,
SELF, D, (phys_bytes) tmp, (phys_bytes) n);
if (r < 0) return(r);
tmp[n-1] = 0;
strcpy(string, tmp);
break;
#endif
default:
return(EINVAL);
}
/* Return the number of bytes moved. */
return(n);
}
/*===========================================================================*
* do_getsysinfo *
*===========================================================================*/
PUBLIC int do_getsysinfo()
{
struct mproc *proc_addr;
vir_bytes src_addr, dst_addr;
struct kinfo kinfo;
struct loadinfo loadinfo;
struct pciinfo pciinfo;
static struct proc proctab[NR_PROCS+NR_TASKS];
size_t len;
int s, r;
/* This call leaks important information (the contents of registers). */
if (mp->mp_effuid != 0)
{
printf("PM: unauthorized call of do_getsysinfo by proc %d '%s'\n",
mp->mp_endpoint, mp->mp_name);
sys_sysctl_stacktrace(mp->mp_endpoint);
return EPERM;
}
switch(m_in.info_what) {
case SI_KINFO: /* kernel info is obtained via PM */
sys_getkinfo(&kinfo);
src_addr = (vir_bytes) &kinfo;
len = sizeof(struct kinfo);
break;
case SI_PROC_ADDR: /* get address of PM process table */
proc_addr = &mproc[0];
src_addr = (vir_bytes) &proc_addr;
len = sizeof(struct mproc *);
break;
case SI_PROC_TAB: /* copy entire process table */
src_addr = (vir_bytes) mproc;
len = sizeof(struct mproc) * NR_PROCS;
break;
case SI_KPROC_TAB: /* copy entire process table */
if((r=sys_getproctab(proctab)) != OK)
return r;
src_addr = (vir_bytes) proctab;
len = sizeof(proctab);
break;
case SI_LOADINFO: /* loadinfo is obtained via PM */
sys_getloadinfo(&loadinfo);
src_addr = (vir_bytes) &loadinfo;
len = sizeof(struct loadinfo);
break;
case SI_PCI_INFO: /* PCI info is obtained via PM */
if ((r=getpciinfo(&pciinfo)) != OK)
return r;
src_addr = (vir_bytes) &pciinfo;
len = sizeof(struct pciinfo);
break;
#if ENABLE_SYSCALL_STATS
case SI_CALL_STATS:
src_addr = (vir_bytes) calls_stats;
len = sizeof(calls_stats);
break;
#endif
default:
return(EINVAL);
}
dst_addr = (vir_bytes) m_in.info_where;
if (OK != (s=sys_datacopy(SELF, src_addr, who_e, dst_addr, len)))
return(s);
return(OK);
}
/*===========================================================================*
* do_getsysinfo_up *
*===========================================================================*/
PUBLIC int do_getsysinfo_up()
{
vir_bytes src_addr, dst_addr;
struct loadinfo loadinfo;
size_t len, real_len;
u64_t idle_tsc;
int s;
switch(m_in.SIU_WHAT) {
case SIU_LOADINFO: /* loadinfo is obtained via PM */
if ((s = sys_getloadinfo(&loadinfo)) != OK)
return s;
src_addr = (vir_bytes) &loadinfo;
real_len = sizeof(struct loadinfo);
break;
case SIU_SYSTEMHZ:
src_addr = (vir_bytes) &system_hz;
real_len = sizeof(system_hz);
break;
case SIU_IDLETSC:
if ((s = sys_getidletsc(&idle_tsc)) != OK)
return s;
src_addr = (vir_bytes) &idle_tsc;
real_len = sizeof(idle_tsc);
break;
default:
return(EINVAL);
}
/* Let application know what the length was. */
len = real_len;
if(len > m_in.SIU_LEN)
len = m_in.SIU_LEN;
dst_addr = (vir_bytes) m_in.SIU_WHERE;
if (OK != (s=sys_datacopy(SELF, src_addr, who_e, dst_addr, len)))
return(s);
return(real_len);
}
/*===========================================================================*
* do_getprocnr *
*===========================================================================*/
PUBLIC int do_getprocnr()
{
register struct mproc *rmp;
static char search_key[PROC_NAME_LEN+1];
int key_len;
int s;
/* This call should be moved to DS. */
if (mp->mp_effuid != 0)
{
/* For now, allow non-root processes to request their own endpoint. */
if (m_in.pid < 0 && m_in.namelen == 0) {
mp->mp_reply.PM_ENDPT = who_e;
mp->mp_reply.PM_PENDPT = NONE;
return OK;
}
printf("PM: unauthorized call of do_getprocnr by proc %d\n",
mp->mp_endpoint);
sys_sysctl_stacktrace(mp->mp_endpoint);
return EPERM;
}
#if 0
printf("PM: do_getprocnr(%d) call from endpoint %d, %s\n",
m_in.pid, mp->mp_endpoint, mp->mp_name);
#endif
if (m_in.pid >= 0) { /* lookup process by pid */
if ((rmp = find_proc(m_in.pid)) != NULL) {
mp->mp_reply.PM_ENDPT = rmp->mp_endpoint;
#if 0
printf("PM: pid result: %d\n", rmp->mp_endpoint);
#endif
return(OK);
}
return(ESRCH);
} else if (m_in.namelen > 0) { /* lookup process by name */
key_len = MIN(m_in.namelen, PROC_NAME_LEN);
if (OK != (s=sys_datacopy(who_e, (vir_bytes) m_in.PMBRK_ADDR,
SELF, (vir_bytes) search_key, key_len)))
return(s);
search_key[key_len] = '\0'; /* terminate for safety */
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++) {
if (((rmp->mp_flags & (IN_USE | EXITING)) == IN_USE) &&
strncmp(rmp->mp_name, search_key, key_len)==0) {
mp->mp_reply.PM_ENDPT = rmp->mp_endpoint;
return(OK);
}
}
return(ESRCH);
} else { /* return own/parent process number */
#if 0
printf("PM: endpt result: %d\n", mp->mp_reply.PM_ENDPT);
#endif
mp->mp_reply.PM_ENDPT = who_e;
mp->mp_reply.PM_PENDPT = mproc[mp->mp_parent].mp_endpoint;
}
return(OK);
}
/*===========================================================================*
* do_getepinfo *
*===========================================================================*/
PUBLIC int do_getepinfo()
{
register struct mproc *rmp;
endpoint_t ep;
/* This call should be moved to DS. */
if (mp->mp_effuid != 0)
{
printf("PM: unauthorized call of do_getepinfo by proc %d\n",
mp->mp_endpoint);
sys_sysctl_stacktrace(mp->mp_endpoint);
return EPERM;
}
ep= m_in.PM_ENDPT;
for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++) {
if ((rmp->mp_flags & IN_USE) && (rmp->mp_endpoint == ep)) {
mp->mp_reply.reply_res2 = rmp->mp_effuid;
mp->mp_reply.reply_res3 = rmp->mp_effgid;
return(rmp->mp_pid);
}
}
/* Process not found */
return(ESRCH);
}
/*===========================================================================*
* do_reboot *
*===========================================================================*/
PUBLIC int do_reboot()
{
message m;
/* Check permission to abort the system. */
if (mp->mp_effuid != SUPER_USER) return(EPERM);
/* See how the system should be aborted. */
abort_flag = (unsigned) m_in.reboot_flag;
if (abort_flag >= RBT_INVALID) return(EINVAL);
if (RBT_MONITOR == abort_flag) {
int r;
if(m_in.reboot_strlen >= sizeof(monitor_code))
return EINVAL;
if((r = sys_datacopy(who_e, (vir_bytes) m_in.reboot_code,
SELF, (vir_bytes) monitor_code, m_in.reboot_strlen)) != OK)
return r;
monitor_code[m_in.reboot_strlen] = '\0';
}
else
monitor_code[0] = '\0';
/* Order matters here. When FS is told to reboot, it exits all its
* processes, and then would be confused if they're exited again by
* SIGKILL. So first kill, then reboot.
*/
check_sig(-1, SIGKILL, FALSE /* ksig*/); /* kill all users except init */
sys_stop(INIT_PROC_NR); /* stop init, but keep it around */
/* Tell FS to reboot */
m.m_type = PM_REBOOT;
tell_fs(&mproc[FS_PROC_NR], &m);
return(SUSPEND); /* don't reply to caller */
}
/*===========================================================================*
* do_getsetpriority *
*===========================================================================*/
PUBLIC int do_getsetpriority()
{
int r, arg_which, arg_who, arg_pri, new_q;
struct mproc *rmp;
arg_which = m_in.m1_i1;
arg_who = m_in.m1_i2;
arg_pri = m_in.m1_i3; /* for SETPRIORITY */
/* Code common to GETPRIORITY and SETPRIORITY. */
/* Only support PRIO_PROCESS for now. */
if (arg_which != PRIO_PROCESS)
return(EINVAL);
if (arg_who == 0)
rmp = mp;
else
if ((rmp = find_proc(arg_who)) == NULL)
return(ESRCH);
if (mp->mp_effuid != SUPER_USER &&
mp->mp_effuid != rmp->mp_effuid && mp->mp_effuid != rmp->mp_realuid)
return EPERM;
/* If GET, that's it. */
if (call_nr == GETPRIORITY) {
return(rmp->mp_nice - PRIO_MIN);
}
/* Only root is allowed to reduce the nice level. */
if (rmp->mp_nice > arg_pri && mp->mp_effuid != SUPER_USER)
return(EACCES);
/* We're SET, and it's allowed.
*
* The value passed in is currently between PRIO_MIN and PRIO_MAX.
* We have to scale this between MIN_USER_Q and MAX_USER_Q to match
* the kernel's scheduling queues.
*/
if ((r = sched_nice(rmp, arg_pri)) != OK) {
return r;
}
rmp->mp_nice = arg_pri;
return(OK);
}
/*===========================================================================*
* do_svrctl *
*===========================================================================*/
PUBLIC int do_svrctl()
{
int s, req;
vir_bytes ptr;
#define MAX_LOCAL_PARAMS 2
static struct {
char name[30];
char value[30];
} local_param_overrides[MAX_LOCAL_PARAMS];
static int local_params = 0;
req = m_in.svrctl_req;
ptr = (vir_bytes) m_in.svrctl_argp;
/* Is the request indeed for the MM? */
if (((req >> 8) & 0xFF) != 'M') return(EINVAL);
/* Control operations local to the PM. */
switch(req) {
case MMSETPARAM:
case MMGETPARAM: {
struct sysgetenv sysgetenv;
char search_key[64];
char *val_start;
size_t val_len;
size_t copy_len;
/* Copy sysgetenv structure to PM. */
if (sys_datacopy(who_e, ptr, SELF, (vir_bytes) &sysgetenv,
sizeof(sysgetenv)) != OK) return(EFAULT);
/* Set a param override? */
if (req == MMSETPARAM) {
if (local_params >= MAX_LOCAL_PARAMS) return ENOSPC;
if (sysgetenv.keylen <= 0
|| sysgetenv.keylen >=
sizeof(local_param_overrides[local_params].name)
|| sysgetenv.vallen <= 0
|| sysgetenv.vallen >=
sizeof(local_param_overrides[local_params].value))
return EINVAL;
if ((s = sys_datacopy(who_e, (vir_bytes) sysgetenv.key,
SELF, (vir_bytes) local_param_overrides[local_params].name,
sysgetenv.keylen)) != OK)
return s;
if ((s = sys_datacopy(who_e, (vir_bytes) sysgetenv.val,
SELF, (vir_bytes) local_param_overrides[local_params].value,
sysgetenv.vallen)) != OK)
return s;
local_param_overrides[local_params].name[sysgetenv.keylen] = '\0';
local_param_overrides[local_params].value[sysgetenv.vallen] = '\0';
local_params++;
return OK;
}
if (sysgetenv.keylen == 0) { /* copy all parameters */
val_start = monitor_params;
val_len = sizeof(monitor_params);
}
else { /* lookup value for key */
int p;
/* Try to get a copy of the requested key. */
if (sysgetenv.keylen > sizeof(search_key)) return(EINVAL);
if ((s = sys_datacopy(who_e, (vir_bytes) sysgetenv.key,
SELF, (vir_bytes) search_key, sysgetenv.keylen)) != OK)
return(s);
/* Make sure key is null-terminated and lookup value.
* First check local overrides.
*/
search_key[sysgetenv.keylen-1]= '\0';
for(p = 0; p < local_params; p++) {
if (!strcmp(search_key, local_param_overrides[p].name)) {
val_start = local_param_overrides[p].value;
break;
}
}
if (p >= local_params && (val_start = find_param(search_key)) == NULL)
return(ESRCH);
val_len = strlen(val_start) + 1;
}
/* See if it fits in the client's buffer. */
if (val_len > sysgetenv.vallen)
return E2BIG;
/* Value found, make the actual copy (as far as possible). */
copy_len = MIN(val_len, sysgetenv.vallen);
if ((s=sys_datacopy(SELF, (vir_bytes) val_start,
who_e, (vir_bytes) sysgetenv.val, copy_len)) != OK)
return(s);
return OK;
}
default:
return(EINVAL);
}
}
/*===========================================================================*
* _brk *
*===========================================================================*/
extern char *_brksize;
PUBLIC int brk(brk_addr)
char *brk_addr;
{
int r;
/* PM wants to call brk() itself. */
if((r=vm_brk(PM_PROC_NR, brk_addr)) != OK) {
#if 0
printf("PM: own brk(%p) failed: vm_brk() returned %d\n",
brk_addr, r);
#endif
return -1;
}
_brksize = brk_addr;
return 0;
}
/*===========================================================================*
* getpciinfo *
*===========================================================================*/
PRIVATE int getpciinfo(pciinfo)
struct pciinfo *pciinfo;
{
int devind, r;
struct pciinfo_entry *entry;
char *name;
u16_t vid, did;
/* look up PCI process number */
pci_init();
/* start enumerating devices */
entry = pciinfo->pi_entries;
r = pci_first_dev(&devind, &vid, &did);
while (r)
{
/* fetch device name */
name = pci_dev_name(vid, did);
if (!name)
name = "";
/* store device information in table */
assert((char *) entry < (char *) (pciinfo + 1));
entry->pie_vid = vid;
entry->pie_did = did;
strncpy(entry->pie_name, name, sizeof(entry->pie_name));
entry->pie_name[sizeof(entry->pie_name) - 1] = 0;
entry++;
/* continue with the next device */
r = pci_next_dev(&devind, &vid, &did);
}
/* store number of entries */
pciinfo->pi_count = entry - pciinfo->pi_entries;
return OK;
}
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