minix/servers/fs/main.c

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2005-04-21 16:53:53 +02:00
/* This file contains the main program of the File System. It consists of
* a loop that gets messages requesting work, carries out the work, and sends
* replies.
*
* The entry points into this file are:
* main: main program of the File System
* reply: send a reply to a process after the requested work is done
*
* Changes:
* Mar 23, 2005 allow arbitrary partitions as RAM disk (Jorrit N. Herder)
* Jan 10, 2005 register fkeys with TTY for debug dumps (Jorrit N. Herder)
*/
struct super_block; /* proto.h needs to know this */
#include "fs.h"
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ioc_memory.h>
#include <sys/svrctl.h>
#include <minix/utils.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/keymap.h>
#include "buf.h"
#include "dmap.h"
#include "file.h"
#include "fproc.h"
#include "inode.h"
#include "param.h"
#include "super.h"
FORWARD _PROTOTYPE( void fs_init, (void) );
FORWARD _PROTOTYPE( int igetenv, (char *var) );
FORWARD _PROTOTYPE( void get_work, (void) );
FORWARD _PROTOTYPE( void load_ram, (void) );
FORWARD _PROTOTYPE( void load_super, (Dev_t super_dev) );
/*===========================================================================*
* main *
*===========================================================================*/
PUBLIC void main()
{
/* This is the main program of the file system. The main loop consists of
* three major activities: getting new work, processing the work, and sending
* the reply. This loop never terminates as long as the file system runs.
*/
int error;
fs_init();
/* This is the main loop that gets work, processes it, and sends replies. */
while (TRUE) {
get_work(); /* sets who and call_nr */
fp = &fproc[who]; /* pointer to proc table struct */
super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */
/* Check for special control messages first. */
if (call_nr == HARD_STOP) {
do_sync();
sys_exit(0); /* never returns */
} else if (call_nr == FKEY_PRESSED) {
do_fkey_pressed();
continue; /* get work again */
}
/* Call the internal function that does the work. */
if (call_nr < 0 || call_nr >= NCALLS)
error = ENOSYS;
else
error = (*call_vec[call_nr])();
/* Copy the results back to the user and send reply. */
if (error != SUSPEND) { reply(who, error); }
if (rdahed_inode != NIL_INODE) {
read_ahead(); /* do block read ahead */
}
}
}
/*===========================================================================*
* get_work *
*===========================================================================*/
PRIVATE void get_work()
{
/* Normally wait for new input. However, if 'reviving' is
* nonzero, a suspended process must be awakened.
*/
register struct fproc *rp;
if (reviving != 0) {
/* Revive a suspended process. */
for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++)
if (rp->fp_revived == REVIVING) {
who = (int)(rp - fproc);
call_nr = rp->fp_fd & BYTE;
m_in.fd = (rp->fp_fd >>8) & BYTE;
m_in.buffer = rp->fp_buffer;
m_in.nbytes = rp->fp_nbytes;
rp->fp_suspended = NOT_SUSPENDED; /*no longer hanging*/
rp->fp_revived = NOT_REVIVING;
reviving--;
return;
}
panic("get_work couldn't revive anyone", NO_NUM);
}
/* Normal case. No one to revive. */
if (receive(ANY, &m_in) != OK) panic("fs receive error", NO_NUM);
who = m_in.m_source;
call_nr = m_in.m_type;
}
/*===========================================================================*
* buf_pool *
*===========================================================================*/
PRIVATE void buf_pool(void)
{
/* Initialize the buffer pool. */
register struct buf *bp;
bufs_in_use = 0;
front = &buf[0];
rear = &buf[NR_BUFS - 1];
for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++) {
bp->b_blocknr = NO_BLOCK;
bp->b_dev = NO_DEV;
bp->b_next = bp + 1;
bp->b_prev = bp - 1;
}
buf[0].b_prev = NIL_BUF;
buf[NR_BUFS - 1].b_next = NIL_BUF;
for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++) bp->b_hash = bp->b_next;
buf_hash[0] = front;
}
/*===========================================================================*
* reply *
*===========================================================================*/
PUBLIC void reply(whom, result)
int whom; /* process to reply to */
int result; /* result of the call (usually OK or error #) */
{
/* Send a reply to a user process. It may fail (if the process has just
* been killed by a signal), so don't check the return code. If the send
* fails, just ignore it.
*/
int s;
m_out.reply_type = result;
s = send(whom, &m_out);
if (s != OK) printf("FS: couldn't send reply: %d\n", s);
}
/*===========================================================================*
* fs_init *
*===========================================================================*/
PRIVATE void fs_init()
{
/* Initialize global variables, tables, etc. */
register struct inode *rip;
int key, i;
message mess;
/* The following initializations are needed to let dev_opcl succeed .*/
fp = (struct fproc *) NULL;
who = FS_PROC_NR;
map_controllers(); /* map controller devices to drivers */
buf_pool(); /* initialize buffer pool */
load_ram(); /* init RAM disk, load if it is root */
load_super(root_dev); /* load super block for root device */
/* Initialize the 'fproc' fields for process 0 .. INIT. */
for (i = 0; i <= LOW_USER; i+= 1) {
if (i == FS_PROC_NR) continue; /* do not initialize FS */
fp = &fproc[i];
rip = get_inode(root_dev, ROOT_INODE);
fp->fp_rootdir = rip;
dup_inode(rip);
fp->fp_workdir = rip;
fp->fp_realuid = (uid_t) SYS_UID;
fp->fp_effuid = (uid_t) SYS_UID;
fp->fp_realgid = (gid_t) SYS_GID;
fp->fp_effgid = (gid_t) SYS_GID;
fp->fp_umask = ~0;
fp->fp_pid = i < LOW_USER ? PID_SERVER : 1;
}
/* Certain relations must hold for the file system to work at all.
* (Some extra block_size requirements are checked at super-block-read-in
* time.)
*/
if (OPEN_MAX > 127) panic("OPEN_MAX > 127", NO_NUM);
if (NR_BUFS < 6) panic("NR_BUFS < 6", NO_NUM);
if (V1_INODE_SIZE != 32) panic("V1 inode size != 32", NO_NUM);
if (V2_INODE_SIZE != 64) panic("V2 inode size != 64", NO_NUM);
if (OPEN_MAX > 8 * sizeof(long)) panic("Too few bits in fp_cloexec", NO_NUM);
/* Tell the memory task where my process table is for the sake of ps(1). */
mess.m_type = DEV_IOCTL;
mess.PROC_NR = FS_PROC_NR;
mess.DEVICE = RAM_DEV;
mess.REQUEST = MIOCSPSINFO;
mess.ADDRESS = (void *) fproc;
(void) sendrec(MEMORY, &mess);
/* Register function keys with TTY. */
for (key=SF5; key<=SF6; key++) {
if ((i=fkey_enable(key))!=OK) {
printf("Warning: FS couldn't register Shift+F%d key: %d\n",
SF1-key+1, i);
}
}
}
/*===========================================================================*
* igetenv *
*===========================================================================*/
PRIVATE int igetenv(key)
char *key;
{
/* Ask kernel for an integer valued boot environment variable. */
char value[64];
int i;
if ((i = get_mon_param(key, value, sizeof(value))) != OK)
printf("FS: Warning, couldn't get monitor param: %d\n", i);
return(atoi(value));
}
/*===========================================================================*
* load_ram *
*===========================================================================*/
PRIVATE void load_ram(void)
{
/* Allocate a RAM disk with size given in the boot parameters. If a RAM disk
* image is given, the copy the entire image device block-by-block to a RAM
* disk with the same size as the image.
* If the root device is not set, the RAM disk will be used as root instead.
*/
register struct buf *bp, *bp1;
u32_t lcount, ram_size_kb;
zone_t zones;
struct super_block *sp, *dsp;
block_t b;
Dev_t image_dev;
int r;
static char sbbuf[MIN_BLOCK_SIZE];
int block_size_image, block_size_ram, ramfs_block_size;
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/* Get some boot environment variables. */
root_dev = igetenv("rootdev");
image_dev = igetenv("ramimagedev");
ram_size_kb = igetenv("ramsize");
/* Open the root device. */
if (dev_open(root_dev, FS_PROC_NR, R_BIT|W_BIT) != OK) {
panic("Cannot open root device",NO_NUM);
}
/* If we must initialize a ram disk, get details from the image device. */
if (root_dev == DEV_RAM || root_dev != image_dev) {
u32_t fsmax;
if (dev_open(image_dev, FS_PROC_NR, R_BIT) != OK)
panic("Cannot open RAM image device", NO_NUM);
/* Get size of RAM disk image from the super block. */
sp = &super_block[0];
sp->s_dev = image_dev;
if (read_super(sp) != OK) panic("Bad RAM disk image FS", NO_NUM);
lcount = sp->s_zones << sp->s_log_zone_size; /* # blks on root dev*/
/* Stretch the RAM disk file system to the boot parameters size, but
* no further than the last zone bit map block allows.
*/
if (ram_size_kb*1024 < lcount*sp->s_block_size)
ram_size_kb = lcount*sp->s_block_size/1024;
fsmax = (u32_t) sp->s_zmap_blocks * CHAR_BIT * sp->s_block_size;
fsmax = (fsmax + (sp->s_firstdatazone-1)) << sp->s_log_zone_size;
if (ram_size_kb*1024 > fsmax*sp->s_block_size)
ram_size_kb = fsmax*sp->s_block_size/1024;
}
/* Tell RAM driver how big the RAM disk must be. */
m_out.m_type = DEV_IOCTL;
m_out.PROC_NR = FS_PROC_NR;
m_out.DEVICE = RAM_DEV;
m_out.REQUEST = MIOCRAMSIZE;
m_out.POSITION = ram_size_kb*1024;
if (sendrec(MEMORY, &m_out) != OK || m_out.REP_STATUS != OK)
panic("Can't set RAM disk size", NO_NUM);
/* Tell MM the RAM disk size, and wait for it to come "on-line". */
m_out.MEM_CHUNK_SIZE = ((long) ram_size_kb * 1024) >> CLICK_SHIFT;
if (sendrec(MM_PROC_NR, &m_out) != OK)
panic("FS can't sync up with MM", NO_NUM);
#if ENABLE_CACHE2
/* The RAM disk is a second level block cache while not otherwise used. */
init_cache2(ram_size);
#endif
/* See if we must load the RAM disk image, otherwise return. */
if (root_dev != DEV_RAM && root_dev == image_dev)
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return;
/* Copy the blocks one at a time from the image to the RAM disk. */
printf("Loading RAM disk.\33[23CLoaded: 0K ");
inode[0].i_mode = I_BLOCK_SPECIAL; /* temp inode for rahead() */
inode[0].i_size = LONG_MAX;
inode[0].i_dev = image_dev;
inode[0].i_zone[0] = image_dev;
block_size_ram = get_block_size(DEV_RAM);
block_size_image = get_block_size(image_dev);
if(block_size_ram != block_size_image) {
printf("ram block size: %d image block size: %d\n",
block_size_ram, block_size_image);
panic("Sorry, ram disk and image disk block sizes have to be the same.", NO_NUM);
}
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for (b = 0; b < (block_t) lcount; b++) {
bp = rahead(&inode[0], b, (off_t)block_size_image * b, block_size_image);
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bp1 = get_block(root_dev, b, NO_READ);
memcpy(bp1->b_data, bp->b_data, (size_t) block_size_image);
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bp1->b_dirt = DIRTY;
put_block(bp, FULL_DATA_BLOCK);
put_block(bp1, FULL_DATA_BLOCK);
printf("\b\b\b\b\b\b\b%5ldK ", ((long) b * block_size_image)/1024L);
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}
printf("\rRAM disk of %u kb loaded.\33[K", ram_size_kb);
if (root_dev == DEV_RAM) printf(" RAM disk is used as root FS.");
printf("\n\n");
/* Invalidate and close the image device. */
invalidate(image_dev);
dev_close(image_dev);
/* Resize the RAM disk root file system. */
if(dev_io(DEV_READ, root_dev, FS_PROC_NR,
sbbuf, SUPER_BLOCK_BYTES, MIN_BLOCK_SIZE, 0) != MIN_BLOCK_SIZE) {
printf("WARNING: ramdisk read for resizing failed\n");
}
dsp = (struct super_block *) sbbuf;
if(dsp->s_magic == SUPER_V3)
ramfs_block_size = dsp->s_block_size;
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else
ramfs_block_size = STATIC_BLOCK_SIZE;
zones = (ram_size_kb * 1024 / ramfs_block_size) >> sp->s_log_zone_size;
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dsp->s_nzones = conv2(sp->s_native, (u16_t) zones);
dsp->s_zones = conv4(sp->s_native, zones);
if(dev_io(DEV_WRITE, root_dev, FS_PROC_NR,
sbbuf, SUPER_BLOCK_BYTES, MIN_BLOCK_SIZE, 0) != MIN_BLOCK_SIZE) {
printf("WARNING: ramdisk write for resizing failed\n");
}
}
/*===========================================================================*
* load_super *
*===========================================================================*/
PRIVATE void load_super(super_dev)
dev_t super_dev; /* place to get superblock from */
{
int bad;
register struct super_block *sp;
register struct inode *rip;
/* Initialize the super_block table. */
for (sp = &super_block[0]; sp < &super_block[NR_SUPERS]; sp++)
sp->s_dev = NO_DEV;
/* Read in super_block for the root file system. */
sp = &super_block[0];
sp->s_dev = super_dev;
/* Check super_block for consistency. */
bad = (read_super(sp) != OK);
if (!bad) {
rip = get_inode(super_dev, ROOT_INODE); /* inode for root dir */
if ( (rip->i_mode & I_TYPE) != I_DIRECTORY || rip->i_nlinks < 3) bad++;
}
if (bad) panic("Invalid root file system", NO_NUM);
sp->s_imount = rip;
dup_inode(rip);
sp->s_isup = rip;
sp->s_rd_only = 0;
return;
}