460 lines
15 KiB
C
460 lines
15 KiB
C
/* This file contains the main program of the File System. It consists of
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* a loop that gets messages requesting work, carries out the work, and sends
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* replies.
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*
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* The entry points into this file are:
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* main: main program of the File System
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* reply: send a reply to a process after the requested work is done
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*
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*/
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struct super_block; /* proto.h needs to know this */
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#include "fs.h"
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#include <fcntl.h>
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#include <string.h>
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#include <stdio.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <sys/ioc_memory.h>
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#include <sys/svrctl.h>
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#include <minix/callnr.h>
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#include <minix/com.h>
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#include <minix/keymap.h>
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#include <minix/const.h>
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#include "buf.h"
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#include "file.h"
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#include "fproc.h"
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#include "inode.h"
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#include "param.h"
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#include "super.h"
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FORWARD _PROTOTYPE( void fs_init, (void) );
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FORWARD _PROTOTYPE( int igetenv, (char *var, int optional) );
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FORWARD _PROTOTYPE( void get_work, (void) );
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FORWARD _PROTOTYPE( void load_ram, (void) );
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FORWARD _PROTOTYPE( void load_super, (Dev_t super_dev) );
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/*===========================================================================*
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* main *
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*===========================================================================*/
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PUBLIC int main()
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{
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/* This is the main program of the file system. The main loop consists of
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* three major activities: getting new work, processing the work, and sending
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* the reply. This loop never terminates as long as the file system runs.
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*/
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sigset_t sigset;
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int error;
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fs_init();
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/* This is the main loop that gets work, processes it, and sends replies. */
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while (TRUE) {
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get_work(); /* sets who and call_nr */
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fp = &fproc[who]; /* pointer to proc table struct */
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super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */
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/* Check for special control messages first. */
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if (call_nr == SYS_SIG) {
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sigset = m_in.NOTIFY_ARG;
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if (sigismember(&sigset, SIGKSTOP)) {
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do_sync();
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sys_exit(0); /* never returns */
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}
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} else if (call_nr == SYN_ALARM) {
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/* Not a user request; system has expired one of our timers,
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* currently only in use for select(). Check it.
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*/
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fs_expire_timers(m_in.NOTIFY_TIMESTAMP);
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} else if ((call_nr & NOTIFY_MESSAGE)) {
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/* Device notifies us of an event. */
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dev_status(&m_in);
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} else {
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/* Call the internal function that does the work. */
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if (call_nr < 0 || call_nr >= NCALLS) {
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error = ENOSYS;
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printf("FS, warning illegal %d system call by %d\n", call_nr, who);
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} else if (fp->fp_pid == PID_FREE) {
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error = ENOSYS;
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printf("FS, bad process, who = %d, call_nr = %d, slot1 = %d\n",
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who, call_nr, m_in.slot1);
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} else {
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error = (*call_vec[call_nr])();
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}
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/* Copy the results back to the user and send reply. */
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if (error != SUSPEND) { reply(who, error); }
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if (rdahed_inode != NIL_INODE) {
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read_ahead(); /* do block read ahead */
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}
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}
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}
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return(OK); /* shouldn't come here */
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}
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/*===========================================================================*
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* get_work *
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*===========================================================================*/
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PRIVATE void get_work()
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{
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/* Normally wait for new input. However, if 'reviving' is
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* nonzero, a suspended process must be awakened.
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*/
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register struct fproc *rp;
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if (reviving != 0) {
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/* Revive a suspended process. */
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for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++)
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if (rp->fp_revived == REVIVING) {
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who = (int)(rp - fproc);
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call_nr = rp->fp_fd & BYTE;
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m_in.fd = (rp->fp_fd >>8) & BYTE;
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m_in.buffer = rp->fp_buffer;
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m_in.nbytes = rp->fp_nbytes;
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rp->fp_suspended = NOT_SUSPENDED; /*no longer hanging*/
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rp->fp_revived = NOT_REVIVING;
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reviving--;
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return;
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}
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panic(__FILE__,"get_work couldn't revive anyone", NO_NUM);
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}
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/* Normal case. No one to revive. */
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if (receive(ANY, &m_in) != OK) panic(__FILE__,"fs receive error", NO_NUM);
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who = m_in.m_source;
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call_nr = m_in.m_type;
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}
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/*===========================================================================*
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* buf_pool *
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*===========================================================================*/
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PRIVATE void buf_pool(void)
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{
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/* Initialize the buffer pool. */
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register struct buf *bp;
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bufs_in_use = 0;
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front = &buf[0];
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rear = &buf[NR_BUFS - 1];
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for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++) {
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bp->b_blocknr = NO_BLOCK;
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bp->b_dev = NO_DEV;
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bp->b_next = bp + 1;
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bp->b_prev = bp - 1;
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}
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buf[0].b_prev = NIL_BUF;
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buf[NR_BUFS - 1].b_next = NIL_BUF;
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for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++) bp->b_hash = bp->b_next;
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buf_hash[0] = front;
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}
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/*===========================================================================*
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* reply *
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*===========================================================================*/
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PUBLIC void reply(whom, result)
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int whom; /* process to reply to */
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int result; /* result of the call (usually OK or error #) */
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{
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/* Send a reply to a user process. It may fail (if the process has just
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* been killed by a signal), so don't check the return code. If the send
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* fails, just ignore it.
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*/
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int s;
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m_out.reply_type = result;
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s = send(whom, &m_out);
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if (s != OK) printf("FS: couldn't send reply %d: %d\n", result, s);
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}
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/*===========================================================================*
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* fs_init *
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*===========================================================================*/
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PRIVATE void fs_init()
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{
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/* Initialize global variables, tables, etc. */
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register struct inode *rip;
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register struct fproc *rfp;
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message mess;
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int s;
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/* Initialize the process table with help of the process manager messages.
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* Expect one message for each system process with its slot number and pid.
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* When no more processes follow, the magic process number NONE is sent.
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* Then, stop and synchronize with the PM.
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*/
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do {
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if (OK != (s=receive(PM_PROC_NR, &mess)))
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panic(__FILE__,"FS couldn't receive from PM", s);
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if (NONE == mess.PR_PROC_NR) break;
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rfp = &fproc[mess.PR_PROC_NR];
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rfp->fp_pid = mess.PR_PID;
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rfp->fp_realuid = (uid_t) SYS_UID;
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rfp->fp_effuid = (uid_t) SYS_UID;
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rfp->fp_realgid = (gid_t) SYS_GID;
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rfp->fp_effgid = (gid_t) SYS_GID;
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rfp->fp_umask = ~0;
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} while (TRUE); /* continue until process NONE */
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mess.m_type = OK; /* tell PM that we succeeded */
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s=send(PM_PROC_NR, &mess); /* send synchronization message */
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/* All process table entries have been set. Continue with FS initialization.
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* Certain relations must hold for the file system to work at all. Some
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* extra block_size requirements are checked at super-block-read-in time.
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*/
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if (OPEN_MAX > 127) panic(__FILE__,"OPEN_MAX > 127", NO_NUM);
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if (NR_BUFS < 6) panic(__FILE__,"NR_BUFS < 6", NO_NUM);
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if (V1_INODE_SIZE != 32) panic(__FILE__,"V1 inode size != 32", NO_NUM);
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if (V2_INODE_SIZE != 64) panic(__FILE__,"V2 inode size != 64", NO_NUM);
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if (OPEN_MAX > 8 * sizeof(long))
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panic(__FILE__,"Too few bits in fp_cloexec", NO_NUM);
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/* The following initializations are needed to let dev_opcl succeed .*/
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fp = (struct fproc *) NULL;
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who = FS_PROC_NR;
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buf_pool(); /* initialize buffer pool */
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build_dmap(); /* build device table and map boot driver */
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load_ram(); /* init RAM disk, load if it is root */
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load_super(root_dev); /* load super block for root device */
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init_select(); /* init select() structures */
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/* The root device can now be accessed; set process directories. */
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for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
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if (rfp->fp_pid != PID_FREE) {
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rip = get_inode(root_dev, ROOT_INODE);
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dup_inode(rip);
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rfp->fp_rootdir = rip;
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rfp->fp_workdir = rip;
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}
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}
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}
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/*===========================================================================*
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* igetenv *
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*===========================================================================*/
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PRIVATE int igetenv(key, optional)
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char *key;
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int optional;
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{
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/* Ask kernel for an integer valued boot environment variable. */
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char value[64];
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int i;
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if ((i = env_get_param(key, value, sizeof(value))) != OK) {
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if (!optional)
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printf("FS: Warning, couldn't get monitor param: %d\n", i);
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return 0;
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}
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return(atoi(value));
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}
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/*===========================================================================*
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* load_ram *
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*===========================================================================*/
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PRIVATE void load_ram(void)
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{
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/* Allocate a RAM disk with size given in the boot parameters. If a RAM disk
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* image is given, the copy the entire image device block-by-block to a RAM
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* disk with the same size as the image.
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* If the root device is not set, the RAM disk will be used as root instead.
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*/
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register struct buf *bp, *bp1;
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u32_t lcount, ram_size_kb;
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zone_t zones;
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struct super_block *sp, *dsp;
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block_t b;
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Dev_t image_dev;
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static char sbbuf[_MIN_BLOCK_SIZE];
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int block_size_image, block_size_ram, ramfs_block_size;
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int s;
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/* Get some boot environment variables. */
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root_dev = igetenv("rootdev", 0);
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image_dev = igetenv("ramimagedev", 0);
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ram_size_kb = igetenv("ramsize", 0);
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/* Open the root device. */
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if (dev_open(root_dev, FS_PROC_NR, R_BIT|W_BIT) != OK)
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panic(__FILE__,"Cannot open root device",NO_NUM);
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/* If we must initialize a ram disk, get details from the image device. */
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if (root_dev == DEV_RAM) {
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u32_t fsmax, probedev;
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/* If we are running from CD, see if we can find it. */
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if (igetenv("cdproberoot", 1) && (probedev=cdprobe()) != NO_DEV) {
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char devnum[10];
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struct sysgetenv env;
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/* If so, this is our new RAM image device. */
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image_dev = probedev;
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/* Tell PM about it, so userland can find out about it
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* with sysenv interface.
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*/
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env.key = "cdproberoot";
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env.keylen = strlen(env.key);
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sprintf(devnum, "%d", (int) probedev);
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env.val = devnum;
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env.vallen = strlen(devnum);
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svrctl(MMSETPARAM, &env);
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}
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/* Open image device for RAM root. */
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if (dev_open(image_dev, FS_PROC_NR, R_BIT) != OK)
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panic(__FILE__,"Cannot open RAM image device", NO_NUM);
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/* Get size of RAM disk image from the super block. */
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sp = &super_block[0];
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sp->s_dev = image_dev;
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if (read_super(sp) != OK)
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panic(__FILE__,"Bad RAM disk image FS", NO_NUM);
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lcount = sp->s_zones << sp->s_log_zone_size; /* # blks on root dev*/
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/* Stretch the RAM disk file system to the boot parameters size, but
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* no further than the last zone bit map block allows.
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*/
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if (ram_size_kb*1024 < lcount*sp->s_block_size)
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ram_size_kb = lcount*sp->s_block_size/1024;
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fsmax = (u32_t) sp->s_zmap_blocks * CHAR_BIT * sp->s_block_size;
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fsmax = (fsmax + (sp->s_firstdatazone-1)) << sp->s_log_zone_size;
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if (ram_size_kb*1024 > fsmax*sp->s_block_size)
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ram_size_kb = fsmax*sp->s_block_size/1024;
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}
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/* Tell RAM driver how big the RAM disk must be. */
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m_out.m_type = DEV_IOCTL;
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m_out.PROC_NR = FS_PROC_NR;
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m_out.DEVICE = RAM_DEV;
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m_out.REQUEST = MIOCRAMSIZE; /* I/O control to use */
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m_out.POSITION = (ram_size_kb * 1024); /* request in bytes */
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if ((s=sendrec(MEM_PROC_NR, &m_out)) != OK)
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panic("FS","sendrec from MEM failed", s);
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else if (m_out.REP_STATUS != OK) {
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/* Report and continue, unless RAM disk is required as root FS. */
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if (root_dev != DEV_RAM) {
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report("FS","can't set RAM disk size", m_out.REP_STATUS);
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return;
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} else {
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panic(__FILE__,"can't set RAM disk size", m_out.REP_STATUS);
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}
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}
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#if ENABLE_CACHE2
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/* The RAM disk is a second level block cache while not otherwise used. */
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init_cache2(ram_size);
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#endif
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/* See if we must load the RAM disk image, otherwise return. */
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if (root_dev != DEV_RAM)
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return;
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/* Copy the blocks one at a time from the image to the RAM disk. */
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printf("Loading RAM disk onto /dev/ram:\33[23CLoaded: 0 KB");
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inode[0].i_mode = I_BLOCK_SPECIAL; /* temp inode for rahead() */
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inode[0].i_size = LONG_MAX;
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inode[0].i_dev = image_dev;
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inode[0].i_zone[0] = image_dev;
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block_size_ram = get_block_size(DEV_RAM);
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block_size_image = get_block_size(image_dev);
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/* RAM block size has to be a multiple of the root image block
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* size to make copying easier.
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*/
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if (block_size_image % block_size_ram) {
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printf("\nram block size: %d image block size: %d\n",
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block_size_ram, block_size_image);
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panic(__FILE__, "ram disk block size must be a multiple of "
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"the image disk block size", NO_NUM);
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}
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/* Loading blocks from image device. */
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for (b = 0; b < (block_t) lcount; b++) {
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int rb, factor;
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bp = rahead(&inode[0], b, (off_t)block_size_image * b, block_size_image);
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factor = block_size_image/block_size_ram;
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for(rb = 0; rb < factor; rb++) {
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bp1 = get_block(root_dev, b * factor + rb, NO_READ);
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memcpy(bp1->b_data, bp->b_data + rb * block_size_ram,
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(size_t) block_size_ram);
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bp1->b_dirt = DIRTY;
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put_block(bp1, FULL_DATA_BLOCK);
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}
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put_block(bp, FULL_DATA_BLOCK);
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if (b % 11 == 0)
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printf("\b\b\b\b\b\b\b\b\b%6ld KB", ((long) b * block_size_image)/1024L);
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}
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/* Commit changes to RAM so dev_io will see it. */
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do_sync();
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printf("\rRAM disk of %u KB loaded onto /dev/ram.", (unsigned) ram_size_kb);
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if (root_dev == DEV_RAM) printf(" Using RAM disk as root FS.");
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printf(" \n");
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/* Invalidate and close the image device. */
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invalidate(image_dev);
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dev_close(image_dev);
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/* Resize the RAM disk root file system. */
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if (dev_io(DEV_READ, root_dev, FS_PROC_NR,
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sbbuf, SUPER_BLOCK_BYTES, _MIN_BLOCK_SIZE, 0) != _MIN_BLOCK_SIZE) {
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printf("WARNING: ramdisk read for resizing failed\n");
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}
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dsp = (struct super_block *) sbbuf;
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if (dsp->s_magic == SUPER_V3)
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ramfs_block_size = dsp->s_block_size;
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else
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ramfs_block_size = _STATIC_BLOCK_SIZE;
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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);
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dsp->s_zones = conv4(sp->s_native, zones);
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if (dev_io(DEV_WRITE, root_dev, FS_PROC_NR,
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sbbuf, SUPER_BLOCK_BYTES, _MIN_BLOCK_SIZE, 0) != _MIN_BLOCK_SIZE) {
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printf("WARNING: ramdisk write for resizing failed\n");
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}
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}
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/*===========================================================================*
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* load_super *
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*===========================================================================*/
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PRIVATE void load_super(super_dev)
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dev_t super_dev; /* place to get superblock from */
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{
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int bad;
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register struct super_block *sp;
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register struct inode *rip;
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/* Initialize the super_block table. */
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for (sp = &super_block[0]; sp < &super_block[NR_SUPERS]; sp++)
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sp->s_dev = NO_DEV;
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/* Read in super_block for the root file system. */
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sp = &super_block[0];
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sp->s_dev = super_dev;
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/* Check super_block for consistency. */
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bad = (read_super(sp) != OK);
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if (!bad) {
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rip = get_inode(super_dev, ROOT_INODE); /* inode for root dir */
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if ( (rip->i_mode & I_TYPE) != I_DIRECTORY || rip->i_nlinks < 3) bad++;
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}
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if (bad) panic(__FILE__,"Invalid root file system", NO_NUM);
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sp->s_imount = rip;
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dup_inode(rip);
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sp->s_isup = rip;
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sp->s_rd_only = 0;
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return;
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}
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