| 1 | /* This file contains the main program of the File System. It consists of
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| 2 | * a loop that gets messages requesting work, carries out the work, and sends
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| 3 | * replies.
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| 4 | *
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| 5 | * The entry points into this file are:
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| 6 | * main: main program of the File System
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| 7 | * reply: send a reply to a process after the requested work is done
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| 8 | *
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| 9 | */
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| 10 |
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| 11 | struct super_block; /* proto.h needs to know this */
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| 12 |
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| 13 | #include "fs.h"
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| 14 | #include <fcntl.h>
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| 15 | #include <string.h>
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| 16 | #include <stdio.h>
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| 17 | #include <signal.h>
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| 18 | #include <stdlib.h>
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| 19 | #include <sys/ioc_memory.h>
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| 20 | #include <sys/svrctl.h>
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| 21 | #include <sys/select.h>
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| 22 | #include <minix/callnr.h>
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| 23 | #include <minix/com.h>
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| 24 | #include <minix/keymap.h>
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| 25 | #include <minix/const.h>
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| 26 | #include <minix/endpoint.h>
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| 27 | #include "buf.h"
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| 28 | #include "file.h"
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| 29 | #include "fproc.h"
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| 30 | #include "inode.h"
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| 31 | #include "param.h"
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| 32 | #include "super.h"
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| 33 |
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| 34 | FORWARD _PROTOTYPE( void fs_init, (void) );
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| 35 | FORWARD _PROTOTYPE( void get_work, (void) );
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| 36 | FORWARD _PROTOTYPE( void init_root, (void) );
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| 37 |
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| 38 | /*===========================================================================*
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| 39 | * main *
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| 40 | *===========================================================================*/
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| 41 | PUBLIC int main()
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| 42 | {
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| 43 | /* This is the main program of the file system. The main loop consists of
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| 44 | * three major activities: getting new work, processing the work, and sending
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| 45 | * the reply. This loop never terminates as long as the file system runs.
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| 46 | */
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| 47 | int error;
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| 48 |
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| 49 | fs_init();
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| 50 |
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| 51 |
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| 52 | /* This is the main loop that gets work, processes it, and sends replies. */
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| 53 | while (TRUE) {
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| 54 | get_work(); /* sets who and call_nr */
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| 55 | fp = &fproc[who_p]; /* pointer to proc table struct */
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| 56 | super_user = (fp->fp_effuid == SU_UID ? TRUE : FALSE); /* su? */
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| 57 |
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| 58 | /* Check for special control messages first. */
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| 59 | if (call_nr == PROC_EVENT) {
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| 60 | /* Assume FS got signal. Synchronize, but don't exit. */
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| 61 | do_sync();
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| 62 | } else if (call_nr == SYN_ALARM) {
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| 63 | /* Alarm timer expired. Used only for select(). Check it. */
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| 64 | fs_expire_timers(m_in.NOTIFY_TIMESTAMP);
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| 65 | } else if ((call_nr & NOTIFY_MESSAGE)) {
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| 66 | /* Device notifies us of an event. */
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| 67 | dev_status(&m_in);
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| 68 | } else {
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| 69 | /* Call the internal function that does the work. */
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| 70 | if (call_nr < 0 || call_nr >= NCALLS) {
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| 71 | error = ENOSYS;
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| 72 | /* Not supposed to happen. */
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| 73 | printf("FS, warning illegal %d system call by %d\n", call_nr, who_e);
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| 74 | } else if (fp->fp_pid == PID_FREE) {
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| 75 | error = ENOSYS;
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| 76 | printf("FS, bad process, who = %d, call_nr = %d, endpt1 = %d\n",
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| 77 | who_e, call_nr, m_in.endpt1);
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| 78 | } else {
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| 79 | error = (*call_vec[call_nr])();
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| 80 | }
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| 81 |
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| 82 | /* Copy the results back to the user and send reply. */
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| 83 | if (error != SUSPEND) { reply(who_e, error); }
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| 84 | if (rdahed_inode != NIL_INODE) {
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| 85 | read_ahead(); /* do block read ahead */
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| 86 | }
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| 87 | }
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| 88 | }
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| 89 | return(OK); /* shouldn't come here */
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| 90 | }
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| 91 |
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| 92 | /*===========================================================================*
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| 93 | * get_work *
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| 94 | *===========================================================================*/
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| 95 | PRIVATE void get_work()
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| 96 | {
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| 97 | /* Normally wait for new input. However, if 'reviving' is
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| 98 | * nonzero, a suspended process must be awakened.
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| 99 | */
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| 100 | register struct fproc *rp;
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| 101 |
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| 102 | if (reviving != 0) {
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| 103 | /* Revive a suspended process. */
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| 104 | for (rp = &fproc[0]; rp < &fproc[NR_PROCS]; rp++)
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| 105 | if (rp->fp_pid != PID_FREE && rp->fp_revived == REVIVING) {
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| 106 | who_p = (int)(rp - fproc);
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| 107 | who_e = rp->fp_endpoint;
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| 108 | call_nr = rp->fp_fd & BYTE;
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| 109 | m_in.fd = (rp->fp_fd >>8) & BYTE;
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| 110 | m_in.buffer = rp->fp_buffer;
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| 111 | m_in.nbytes = rp->fp_nbytes;
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| 112 | rp->fp_suspended = NOT_SUSPENDED; /*no longer hanging*/
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| 113 | rp->fp_revived = NOT_REVIVING;
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| 114 | reviving--;
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| 115 | return;
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| 116 | }
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| 117 | panic(__FILE__,"get_work couldn't revive anyone", NO_NUM);
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| 118 | }
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| 119 |
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| 120 | for(;;) {
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| 121 | /* Normal case. No one to revive. */
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| 122 | if (receive(ANY, &m_in) != OK)
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| 123 | panic(__FILE__,"fs receive error", NO_NUM);
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| 124 | who_e = m_in.m_source;
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| 125 | who_p = _ENDPOINT_P(who_e);
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| 126 | if(who_p < -NR_TASKS || who_p >= NR_PROCS)
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| 127 | panic(__FILE__,"receive process out of range", who_p);
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| 128 | if(who_p >= 0 && fproc[who_p].fp_endpoint == NONE) {
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| 129 | printf("FS: ignoring request from %d, endpointless slot %d (%d)\n",
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| 130 | m_in.m_source, who_p, m_in.m_type);
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| 131 | continue;
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| 132 | }
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| 133 | if(who_p >= 0 && fproc[who_p].fp_endpoint != who_e) {
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| 134 | printf("FS: receive endpoint inconsistent (%d, %d, %d).\n",
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| 135 | who_e, fproc[who_p].fp_endpoint, who_e);
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| 136 | panic(__FILE__, "FS: inconsistent endpoint ", NO_NUM);
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| 137 | continue;
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| 138 | }
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| 139 | call_nr = m_in.m_type;
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| 140 | return;
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| 141 | }
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| 142 | }
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| 143 |
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| 144 | /*===========================================================================*
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| 145 | * buf_pool *
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| 146 | *===========================================================================*/
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| 147 | PRIVATE void buf_pool(void)
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| 148 | {
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| 149 | /* Initialize the buffer pool. */
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| 150 |
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| 151 | register struct buf *bp;
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| 152 |
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| 153 | bufs_in_use = 0;
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| 154 | front = &buf[0];
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| 155 | rear = &buf[NR_BUFS - 1];
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| 156 |
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| 157 | for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++) {
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| 158 | bp->b_blocknr = NO_BLOCK;
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| 159 | bp->b_dev = NO_DEV;
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| 160 | bp->b_next = bp + 1;
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| 161 | bp->b_prev = bp - 1;
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| 162 | }
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| 163 | buf[0].b_prev = NIL_BUF;
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| 164 | buf[NR_BUFS - 1].b_next = NIL_BUF;
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| 165 |
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| 166 | for (bp = &buf[0]; bp < &buf[NR_BUFS]; bp++) bp->b_hash = bp->b_next;
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| 167 | buf_hash[0] = front;
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| 168 |
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| 169 | }
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| 170 |
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| 171 | /*===========================================================================*
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| 172 | * reply *
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| 173 | *===========================================================================*/
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| 174 | PUBLIC void reply(whom, result)
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| 175 | int whom; /* process to reply to */
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| 176 | int result; /* result of the call (usually OK or error #) */
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| 177 | {
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| 178 | /* Send a reply to a user process. If the send fails, just ignore it. */
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| 179 | int s;
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| 180 | m_out.reply_type = result;
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| 181 | s = send(whom, &m_out);
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| 182 | if (s != OK) printf("FS: couldn't send reply %d to %d: %d\n",
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| 183 | result, whom, s);
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| 184 | }
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| 185 |
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| 186 | /*===========================================================================*
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| 187 | * fs_init *
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| 188 | *===========================================================================*/
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| 189 | PRIVATE void fs_init()
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| 190 | {
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| 191 | /* Initialize global variables, tables, etc. */
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| 192 | register struct inode *rip;
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| 193 | register struct fproc *rfp;
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| 194 | message mess;
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| 195 | int s;
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| 196 |
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| 197 | /* Initialize the process table with help of the process manager messages.
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| 198 | * Expect one message for each system process with its slot number and pid.
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| 199 | * When no more processes follow, the magic process number NONE is sent.
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| 200 | * Then, stop and synchronize with the PM.
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| 201 | */
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| 202 | do {
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| 203 | if (OK != (s=receive(PM_PROC_NR, &mess)))
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| 204 | panic(__FILE__,"FS couldn't receive from PM", s);
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| 205 | if (NONE == mess.PR_ENDPT) break;
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| 206 |
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| 207 | rfp = &fproc[mess.PR_SLOT];
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| 208 | rfp->fp_pid = mess.PR_PID;
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| 209 | rfp->fp_endpoint = mess.PR_ENDPT;
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| 210 | rfp->fp_realuid = (uid_t) SYS_UID;
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| 211 | rfp->fp_effuid = (uid_t) SYS_UID;
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| 212 | rfp->fp_realgid = (gid_t) SYS_GID;
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| 213 | rfp->fp_effgid = (gid_t) SYS_GID;
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| 214 | rfp->fp_umask = ~0;
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| 215 |
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| 216 | } while (TRUE); /* continue until process NONE */
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| 217 | mess.m_type = OK; /* tell PM that we succeeded */
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| 218 | s=send(PM_PROC_NR, &mess); /* send synchronization message */
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| 219 |
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| 220 | /* All process table entries have been set. Continue with FS initialization.
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| 221 | * Certain relations must hold for the file system to work at all. Some
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| 222 | * extra block_size requirements are checked at super-block-read-in time.
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| 223 | */
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| 224 | if (OPEN_MAX > 127) panic(__FILE__,"OPEN_MAX > 127", NO_NUM);
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| 225 | if (NR_BUFS < 6) panic(__FILE__,"NR_BUFS < 6", NO_NUM);
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| 226 | if (V1_INODE_SIZE != 32) panic(__FILE__,"V1 inode size != 32", NO_NUM);
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| 227 | if (V2_INODE_SIZE != 64) panic(__FILE__,"V2 inode size != 64", NO_NUM);
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| 228 | if (OPEN_MAX > 8 * sizeof(long))
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| 229 | panic(__FILE__,"Too few bits in fp_cloexec", NO_NUM);
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| 230 |
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| 231 | /* The following initializations are needed to let dev_opcl succeed .*/
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| 232 | fp = (struct fproc *) NULL;
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| 233 | who_e = who_p = FS_PROC_NR;
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| 234 |
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| 235 | buf_pool(); /* initialize buffer pool */
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| 236 | build_dmap(); /* build device table and map boot driver */
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| 237 | init_root(); /* init root device and load super block */
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| 238 | init_select(); /* init select() structures */
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| 239 |
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| 240 | /* The root device can now be accessed; set process directories. */
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| 241 | for (rfp=&fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
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| 242 | FD_ZERO(&(rfp->fp_filp_inuse));
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| 243 | if (rfp->fp_pid != PID_FREE) {
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| 244 | rip = get_inode(root_dev, ROOT_INODE);
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| 245 | dup_inode(rip);
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| 246 | rfp->fp_rootdir = rip;
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| 247 | rfp->fp_workdir = rip;
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| 248 | } else rfp->fp_endpoint = NONE;
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| 249 | }
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| 250 | }
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| 251 |
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| 252 | /*===========================================================================*
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| 253 | * init_root *
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| 254 | *===========================================================================*/
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| 255 | PRIVATE void init_root()
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| 256 | {
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| 257 | int bad;
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| 258 | register struct super_block *sp;
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| 259 | register struct inode *rip = NIL_INODE;
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| 260 | int s;
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| 261 |
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| 262 | /* Open the root device. */
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| 263 | root_dev = DEV_IMGRD;
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| 264 | if ((s=dev_open(root_dev, FS_PROC_NR, R_BIT|W_BIT)) != OK)
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| 265 | panic(__FILE__,"Cannot open root device", s);
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| 266 |
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| 267 | #if ENABLE_CACHE2
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| 268 | /* The RAM disk is a second level block cache while not otherwise used. */
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| 269 | init_cache2(ram_size);
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| 270 | #endif
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| 271 |
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| 272 | /* Initialize the super_block table. */
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| 273 | for (sp = &super_block[0]; sp < &super_block[NR_SUPERS]; sp++)
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| 274 | sp->s_dev = NO_DEV;
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| 275 |
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| 276 | /* Read in super_block for the root file system. */
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| 277 | sp = &super_block[0];
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| 278 | sp->s_dev = root_dev;
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| 279 |
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| 280 | /* Check super_block for consistency. */
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| 281 | bad = (read_super(sp) != OK);
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| 282 | if (!bad) {
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| 283 | rip = get_inode(root_dev, ROOT_INODE); /* inode for root dir */
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| 284 | if ( (rip->i_mode & I_TYPE) != I_DIRECTORY || rip->i_nlinks < 3) bad++;
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| 285 | }
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| 286 | if (bad) panic(__FILE__,"Invalid root file system", NO_NUM);
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| 287 |
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| 288 | sp->s_imount = rip;
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| 289 | dup_inode(rip);
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| 290 | sp->s_isup = rip;
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| 291 | sp->s_rd_only = 0;
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| 292 | return;
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| 293 | }
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