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minix/servers/pm/misc.c
Ben Gras 50e2064049 No more intel/minix segments. 
This commit removes all traces of Minix segments (the text/data/stack
memory map abstraction in the kernel) and significance of Intel segments
(hardware segments like CS, DS that add offsets to all addressing before
page table translation). This ultimately simplifies the memory layout
and addressing and makes the same layout possible on non-Intel
architectures.

There are only two types of addresses in the world now: virtual
and physical; even the kernel and processes have the same virtual
address space. Kernel and user processes can be distinguished at a
glance as processes won't use 0xF0000000 and above.

No static pre-allocated memory sizes exist any more.

Changes to booting:
        . The pre_init.c leaves the kernel and modules exactly as
          they were left by the bootloader in physical memory
        . The kernel starts running using physical addressing,
          loaded at a fixed location given in its linker script by the
          bootloader.  All code and data in this phase are linked to
          this fixed low location.
        . It makes a bootstrap pagetable to map itself to a
          fixed high location (also in linker script) and jumps to
          the high address. All code and data then use this high addressing.
        . All code/data symbols linked at the low addresses is prefixed by
          an objcopy step with __k_unpaged_*, so that that code cannot
          reference highly-linked symbols (which aren't valid yet) or vice
          versa (symbols that aren't valid any more).
        . The two addressing modes are separated in the linker script by
          collecting the unpaged_*.o objects and linking them with low
          addresses, and linking the rest high. Some objects are linked
          twice, once low and once high.
        . The bootstrap phase passes a lot of information (e.g. free memory
          list, physical location of the modules, etc.) using the kinfo
          struct.
        . After this bootstrap the low-linked part is freed.
        . The kernel maps in VM into the bootstrap page table so that VM can
          begin executing. Its first job is to make page tables for all other
          boot processes. So VM runs before RS, and RS gets a fully dynamic,
          VM-managed address space. VM gets its privilege info from RS as usual
          but that happens after RS starts running.
        . Both the kernel loading VM and VM organizing boot processes happen
	  using the libexec logic. This removes the last reason for VM to
	  still know much about exec() and vm/exec.c is gone.

Further Implementation:
        . All segments are based at 0 and have a 4 GB limit.
        . The kernel is mapped in at the top of the virtual address
          space so as not to constrain the user processes.
        . Processes do not use segments from the LDT at all; there are
          no segments in the LDT any more, so no LLDT is needed.
        . The Minix segments T/D/S are gone and so none of the
          user-space or in-kernel copy functions use them. The copy
          functions use a process endpoint of NONE to realize it's
          a physical address, virtual otherwise.
        . The umap call only makes sense to translate a virtual address
          to a physical address now.
        . Segments-related calls like newmap and alloc_segments are gone.
        . All segments-related translation in VM is gone (vir2map etc).
        . Initialization in VM is simpler as no moving around is necessary.
        . VM and all other boot processes can be linked wherever they wish
          and will be mapped in at the right location by the kernel and VM
          respectively.

Other changes:
        . The multiboot code is less special: it does not use mb_print
          for its diagnostics any more but uses printf() as normal, saving
          the output into the diagnostics buffer, only printing to the
          screen using the direct print functions if a panic() occurs.
        . The multiboot code uses the flexible 'free memory map list'
          style to receive the list of free memory if available.
        . The kernel determines the memory layout of the processes to
          a degree: it tells VM where the kernel starts and ends and
          where the kernel wants the top of the process to be. VM then
          uses this entire range, i.e. the stack is right at the top,
          and mmap()ped bits of memory are placed below that downwards,
          and the break grows upwards.

Other Consequences:
        . Every process gets its own page table as address spaces
          can't be separated any more by segments.
        . As all segments are 0-based, there is no distinction between
          virtual and linear addresses, nor between userspace and
          kernel addresses.
        . Less work is done when context switching, leading to a net
          performance increase. (8% faster on my machine for 'make servers'.)
	. The layout and configuration of the GDT makes sysenter and syscall
	  possible.
2012-07-15 22:30:15 +02:00

496 lines
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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_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"
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
};
static 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
unsigned long calls_stats[NCALLS];
#endif
/*===========================================================================*
* do_sysuname *
*===========================================================================*/
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, (phys_bytes) string,
mp->mp_endpoint, (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, (phys_bytes) m_in.sysuname_value,
SELF, (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 *
*===========================================================================*/
int do_getsysinfo()
{
vir_bytes src_addr, dst_addr;
size_t len;
/* This call leaks important information. In the future, requests from
* non-system processes should be denied.
*/
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.SI_WHAT) {
case SI_PROC_TAB: /* copy entire process table */
src_addr = (vir_bytes) mproc;
len = sizeof(struct mproc) * NR_PROCS;
break;
#if ENABLE_SYSCALL_STATS
case SI_CALL_STATS:
src_addr = (vir_bytes) calls_stats;
len = sizeof(calls_stats);
break;
#endif
default:
return(EINVAL);
}
if (len != m_in.SI_SIZE)
return(EINVAL);
dst_addr = (vir_bytes) m_in.SI_WHERE;
return sys_datacopy(SELF, src_addr, who_e, dst_addr, len);
}
/*===========================================================================*
* do_getprocnr *
*===========================================================================*/
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 *
*===========================================================================*/
int do_getepinfo()
{
register struct mproc *rmp;
endpoint_t ep;
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_getepinfo_o *
*===========================================================================*/
int do_getepinfo_o()
{
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_o 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 = (short) rmp->mp_effuid;
mp->mp_reply.reply_res3 = (char) rmp->mp_effgid;
return(rmp->mp_pid);
}
}
/* Process not found */
return(ESRCH);
}
/*===========================================================================*
* do_reboot *
*===========================================================================*/
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);
/* Order matters here. When VFS 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 VFS to reboot */
m.m_type = PM_REBOOT;
tell_vfs(&mproc[VFS_PROC_NR], &m);
return(SUSPEND); /* don't reply to caller */
}
/*===========================================================================*
* do_getsetpriority *
*===========================================================================*/
int do_getsetpriority()
{
int r, arg_which, arg_who, arg_pri;
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 *
*===========================================================================*/
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 PM? */
if (((req >> 8) & 0xFF) != 'M') return(EINVAL);
/* Control operations local to the PM. */
switch(req) {
case PMSETPARAM:
case PMGETPARAM: {
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 == PMSETPARAM) {
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;
int brk(brk_addr)
#ifdef __NBSD_LIBC
void *brk_addr;
#else
char *brk_addr;
#endif
{
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;
}
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