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minix/servers/fs/main.c

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/* 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
*
*/
struct super_block; /* proto.h needs to know this */
#include "fs.h"
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/ioc_memory.h>
#include <sys/svrctl.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/keymap.h>
#include <minix/const.h>
#include "buf.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, int optional) );
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.
*/
sigset_t sigset;
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 == SYS_SIG) {
sigset = m_in.NOTIFY_ARG;
if (sigismember(&sigset, SIGKSTOP)) {
do_sync();
sys_exit(0); /* never returns */
}
} else if (call_nr == SYN_ALARM) {
/* Not a user request; system has expired one of our timers,
* currently only in use for select(). Check it.
*/
fs_expire_timers(m_in.NOTIFY_TIMESTAMP);
} else if ((call_nr & NOTIFY_MESSAGE)) {
/* Device notifies us of an event. */
dev_status(&m_in);
} else {
/* Call the internal function that does the work. */
if (call_nr < 0 || call_nr >= NCALLS) {
error = ENOSYS;
printf("FS, warning illegal %d system call by %d\n", call_nr, who);
} else if (fp->fp_pid == PID_FREE) {
error = ENOSYS;
printf("FS, bad process, who = %d, call_nr = %d, slot1 = %d\n", who, call_nr, m_in.slot1);
} 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(__FILE__,"get_work couldn't revive anyone", NO_NUM);
}
/* Normal case. No one to revive. */
if (receive(ANY, &m_in) != OK) panic(__FILE__,"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: %d\n", result, s);
}
/*===========================================================================*
* fs_init *
*===========================================================================*/
PRIVATE void fs_init()
{
/* Initialize global variables, tables, etc. */
register struct inode *rip;
register struct fproc *rfp;
int key, s, i;
message mess;
/* Initialize the process table with help of the process manager messages.
* Expect one message for each system process with its slot number and pid.
* When no more processes follow, the magic process number NONE is sent.
* Then, stop and synchronize with the PM.
*/
do {
if (OK != (s=receive(PM_PROC_NR, &mess)))
panic(__FILE__,"FS couldn't receive from PM", s);
if (NONE == mess.PR_PROC_NR) break;
rfp = &fproc[mess.PR_PROC_NR];
rfp->fp_pid = mess.PR_PID;
rfp->fp_realuid = (uid_t) SYS_UID;
rfp->fp_effuid = (uid_t) SYS_UID;
rfp->fp_realgid = (gid_t) SYS_GID;
rfp->fp_effgid = (gid_t) SYS_GID;
rfp->fp_umask = ~0;
} while (TRUE); /* continue until process NONE */
mess.m_type = OK; /* tell PM that we succeeded */
s=send(PM_PROC_NR, &mess); /* send synchronization message */
/* All process table entries have been set. Continue with FS initialization.
* 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(__FILE__,"OPEN_MAX > 127", NO_NUM);
if (NR_BUFS < 6) panic(__FILE__,"NR_BUFS < 6", NO_NUM);
if (V1_INODE_SIZE != 32) panic(__FILE__,"V1 inode size != 32", NO_NUM);
if (V2_INODE_SIZE != 64) panic(__FILE__,"V2 inode size != 64", NO_NUM);
if (OPEN_MAX > 8 * sizeof(long)) panic(__FILE__,"Too few bits in fp_cloexec", NO_NUM);
/* The following initializations are needed to let dev_opcl succeed .*/
fp = (struct fproc *) NULL;
who = FS_PROC_NR;
buf_pool(); /* initialize buffer pool */
build_dmap(); /* build device table and map boot driver */
load_ram(); /* init RAM disk, load if it is root */
load_super(root_dev); /* load super block for root device */
init_select(); /* init select() structures */
/* The root device can now be accessed; set process directories. */
for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if (rfp->fp_pid != PID_FREE) {
rip = get_inode(root_dev, ROOT_INODE);
dup_inode(rip);
rfp->fp_rootdir = rip;
rfp->fp_workdir = rip;
}
}
}
/*===========================================================================*
* igetenv *
*===========================================================================*/
PRIVATE int igetenv(key, optional)
char *key;
int optional;
{
/* Ask kernel for an integer valued boot environment variable. */
char value[64];
int i;
if ((i = env_get_param(key, value, sizeof(value))) != OK) {
if(!optional)
printf("FS: Warning, couldn't get monitor param: %d\n", i);
return 0;
}
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 s,r;
static char sbbuf[MIN_BLOCK_SIZE];
int block_size_image, block_size_ram, ramfs_block_size;
/* Get some boot environment variables. */
root_dev = igetenv("rootdev", 0);
image_dev = igetenv("ramimagedev", 0);
ram_size_kb = igetenv("ramsize", 0);
/* Open the root device. */
if (dev_open(root_dev, FS_PROC_NR, R_BIT|W_BIT) != OK)
panic(__FILE__,"Cannot open root device",NO_NUM);
/* If we must initialize a ram disk, get details from the image device. */
if (root_dev == DEV_RAM) {
u32_t fsmax, probedev;
/* If we are running from CD, see if we can find it. */
if(igetenv("cdproberoot", 1) && (probedev=cdprobe()) != NO_DEV) {
char devnum[10];
struct sysgetenv env;
/* If so, this is our new RAM image device. */
image_dev = probedev;
/* Tell PM about it, so userland can find out about it
* with sysenv interface.
*/
env.key = "cdproberoot";
env.keylen = strlen(env.key);
sprintf(devnum, "%d", probedev);
env.val = devnum;
env.vallen = strlen(devnum);
svrctl(MMSETPARAM, &env);
}
/* Open image device for RAM root. */
if (dev_open(image_dev, FS_PROC_NR, R_BIT) != OK)
panic(__FILE__,"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(__FILE__,"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; /* I/O control to use */
m_out.POSITION = (ram_size_kb * 1024); /* request in bytes */
if ((s=sendrec(MEM_PROC_NR, &m_out)) != OK)
panic("FS","sendrec from MEM failed", s);
else if (m_out.REP_STATUS != OK) {
/* Report and continue, unless RAM disk is required as root FS. */
if (root_dev != DEV_RAM) {
report("FS","can't set RAM disk size", m_out.REP_STATUS);
return;
} else {
panic(__FILE__,"can't set RAM disk size", m_out.REP_STATUS);
}
}
#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)
return;
/* Copy the blocks one at a time from the image to the RAM disk. */
printf("Loading RAM disk onto /dev/ram:\33[23CLoaded: 0 KB");
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);
/* RAM block size has to be a multiple of the root image block
* size to make copying easier.
*/
if(block_size_image % block_size_ram) {
printf("\nram block size: %d image block size: %d\n",
block_size_ram, block_size_image);
panic(__FILE__, "ram disk block size must be a multiple of the image disk block size", NO_NUM);
}
/* Loading blocks from image device. */
for (b = 0; b < (block_t) lcount; b++) {
int rb, factor;
bp = rahead(&inode[0], b, (off_t)block_size_image * b, block_size_image);
factor = block_size_image/block_size_ram;
for(rb = 0; rb < factor; rb++) {
bp1 = get_block(root_dev, b * factor + rb, NO_READ);
memcpy(bp1->b_data, bp->b_data + rb * block_size_ram,
(size_t) block_size_ram);
bp1->b_dirt = DIRTY;
put_block(bp1, FULL_DATA_BLOCK);
}
put_block(bp, FULL_DATA_BLOCK);
if (b % 11 == 0)
printf("\b\b\b\b\b\b\b\b\b%6ld KB", ((long) b * block_size_image)/1024L);
}
/* Commit changes to RAM so dev_io will see it. */
do_sync();
printf("\rRAM disk of %u KB loaded onto /dev/ram.", ram_size_kb);
if (root_dev == DEV_RAM) printf(" Using RAM disk as root FS.");
printf(" \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;
else
ramfs_block_size = STATIC_BLOCK_SIZE;
zones = (ram_size_kb * 1024 / ramfs_block_size) >> sp->s_log_zone_size;
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(__FILE__,"Invalid root file system", NO_NUM);
sp->s_imount = rip;
dup_inode(rip);
sp->s_isup = rip;
sp->s_rd_only = 0;
return;
}
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