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rearrangements and cleanup for text

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This commit is contained in:
Russ Cox 2009-07-11 19:26:01 -07:00
parent 2de1c550ca
commit f9a06440ab
4 changed files with 102 additions and 107 deletions
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99
fs.c
View file

@ -141,6 +141,53 @@ iinit(void)
initlock(&icache.lock, "icache");
}
static struct inode* iget(uint dev, uint inum);
//PAGEBREAK!
// Allocate a new inode with the given type on device dev.
struct inode*
ialloc(uint dev, short type)
{
int inum;
struct buf *bp;
struct dinode *dip;
struct superblock sb;
readsb(dev, &sb);
for(inum = 1; inum < sb.ninodes; inum++){ // loop over inode blocks
bp = bread(dev, IBLOCK(inum));
dip = (struct dinode*)bp->data + inum%IPB;
if(dip->type == 0){ // a free inode
memset(dip, 0, sizeof(*dip));
dip->type = type;
bwrite(bp); // mark it allocated on the disk
brelse(bp);
return iget(dev, inum);
}
brelse(bp);
}
panic("ialloc: no inodes");
}
// Copy inode, which has changed, from memory to disk.
void
iupdate(struct inode *ip)
{
struct buf *bp;
struct dinode *dip;
bp = bread(ip->dev, IBLOCK(ip->inum));
dip = (struct dinode*)bp->data + ip->inum%IPB;
dip->type = ip->type;
dip->major = ip->major;
dip->minor = ip->minor;
dip->nlink = ip->nlink;
dip->size = ip->size;
memmove(dip->addrs, ip->addrs, sizeof(ip->addrs));
bwrite(bp);
brelse(bp);
}
// Find the inode with number inum on device dev
// and return the in-memory copy.
static struct inode*
@ -262,51 +309,6 @@ iunlockput(struct inode *ip)
iput(ip);
}
//PAGEBREAK!
// Allocate a new inode with the given type on device dev.
struct inode*
ialloc(uint dev, short type)
{
int inum;
struct buf *bp;
struct dinode *dip;
struct superblock sb;
readsb(dev, &sb);
for(inum = 1; inum < sb.ninodes; inum++){ // loop over inode blocks
bp = bread(dev, IBLOCK(inum));
dip = (struct dinode*)bp->data + inum%IPB;
if(dip->type == 0){ // a free inode
memset(dip, 0, sizeof(*dip));
dip->type = type;
bwrite(bp); // mark it allocated on the disk
brelse(bp);
return iget(dev, inum);
}
brelse(bp);
}
panic("ialloc: no inodes");
}
// Copy inode, which has changed, from memory to disk.
void
iupdate(struct inode *ip)
{
struct buf *bp;
struct dinode *dip;
bp = bread(ip->dev, IBLOCK(ip->inum));
dip = (struct dinode*)bp->data + ip->inum%IPB;
dip->type = ip->type;
dip->major = ip->major;
dip->minor = ip->minor;
dip->nlink = ip->nlink;
dip->size = ip->size;
memmove(dip->addrs, ip->addrs, sizeof(ip->addrs));
bwrite(bp);
brelse(bp);
}
//PAGEBREAK!
// Inode contents
//
@ -336,7 +338,6 @@ bmap(struct inode *ip, uint bn)
ip->addrs[NDIRECT] = addr = balloc(ip->dev);
bp = bread(ip->dev, addr);
a = (uint*)bp->data;
if((addr = a[bn]) == 0){
a[bn] = addr = balloc(ip->dev);
bwrite(bp);
@ -571,7 +572,7 @@ skipelem(char *path, char *name)
// If parent != 0, return the inode for the parent and copy the final
// path element into name, which must have room for DIRSIZ bytes.
static struct inode*
namex(char *path, int parent, char *name)
namex(char *path, int nameiparent, char *name)
{
struct inode *ip, *next;
@ -586,7 +587,7 @@ namex(char *path, int parent, char *name)
iunlockput(ip);
return 0;
}
if(parent && *path == '\0'){
if(nameiparent && *path == '\0'){
// Stop one level early.
iunlock(ip);
return ip;
@ -598,7 +599,7 @@ namex(char *path, int parent, char *name)
iunlockput(ip);
ip = next;
}
if(parent){
if(nameiparent){
iput(ip);
return 0;
}

2
initcode.S
View file

@ -8,7 +8,7 @@
start:
pushl $argv
pushl $init
pushl $0
pushl $0 // where caller pc would be
movl $SYS_exec, %eax
int $T_SYSCALL

40
kalloc.c
View file

@ -22,21 +22,20 @@ struct {
// Initialize free list of physical pages.
// This code cheats by just considering one megabyte of
// pages after _end. Real systems would determine the
// pages after end. Real systems would determine the
// amount of memory available in the system and use it all.
void
kinit(void)
{
extern int end;
uint mem;
char *start;
extern char end[];
uint len;
char *p;
initlock(&kmem.lock, "kmem");
start = (char*) &end;
start = (char*) (((uint)start + PAGE) & ~(PAGE-1));
mem = 256; // assume computer has 256 pages of RAM
cprintf("mem = %d\n", mem * PAGE);
kfree(start, mem * PAGE);
p = (char*)(((uint)end + PAGE) & ~(PAGE-1));
len = 256*PAGE; // assume computer has 256 pages of RAM, 1 MB
cprintf("mem = %d\n", len);
kfree(p, len);
}
// Free the len bytes of memory pointed at by v,
@ -61,13 +60,7 @@ kfree(char *v, int len)
rend = (struct run*)((char*)r + r->len);
if(r <= p && p < rend)
panic("freeing free page");
if(pend == r){ // p next to r: replace r with p
p->len = len + r->len;
p->next = r->next;
*rp = p;
goto out;
}
if(rend == p){ // r next to p: replace p with r
if(rend == p){ // r before p: expand r to include p
r->len += len;
if(r->next && r->next == pend){ // r now next to r->next?
r->len += r->next->len;
@ -75,6 +68,12 @@ kfree(char *v, int len)
}
goto out;
}
if(pend == r){ // p before r: expand p to include, replace r
p->len = len + r->len;
p->next = r->next;
*rp = p;
goto out;
}
}
// Insert p before r in list.
p->len = len;
@ -99,14 +98,11 @@ kalloc(int n)
acquire(&kmem.lock);
for(rp=&kmem.freelist; (r=*rp) != 0; rp=&r->next){
if(r->len == n){
*rp = r->next;
release(&kmem.lock);
return (char*)r;
}
if(r->len > n){
if(r->len >= n){
r->len -= n;
p = (char*)r + r->len;
if(r->len == 0)
*rp = r->next;
release(&kmem.lock);
return p;
}

64
sysfile.c
View file

@ -44,6 +44,20 @@ fdalloc(struct file *f)
return -1;
}
int
sys_dup(void)
{
struct file *f;
int fd;
if(argfd(0, 0, &f) < 0)
return -1;
if((fd=fdalloc(f)) < 0)
return -1;
filedup(f);
return fd;
}
int
sys_read(void)
{
@ -68,20 +82,6 @@ sys_write(void)
return filewrite(f, p, n);
}
int
sys_dup(void)
{
struct file *f;
int fd;
if(argfd(0, 0, &f) < 0)
return -1;
if((fd=fdalloc(f)) < 0)
return -1;
filedup(f);
return fd;
}
int
sys_close(void)
{
@ -225,17 +225,15 @@ create(char *path, short type, short major, short minor)
if((ip = dirlookup(dp, name, &off)) != 0){
iunlockput(dp);
ilock(ip);
if(ip->type != type || type != T_FILE){
if(type == T_FILE && ip->type == T_FILE)
return ip;
iunlockput(ip);
return 0;
}
return ip;
}
if((ip = ialloc(dp->dev, type)) == 0){
iunlockput(dp);
return 0;
}
if((ip = ialloc(dp->dev, type)) == 0)
panic("create: ialloc");
ilock(ip);
ip->major = major;
ip->minor = minor;
@ -298,6 +296,18 @@ sys_open(void)
return fd;
}
int
sys_mkdir(void)
{
char *path;
struct inode *ip;
if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0)
return -1;
iunlockput(ip);
return 0;
}
int
sys_mknod(void)
{
@ -315,18 +325,6 @@ sys_mknod(void)
return 0;
}
int
sys_mkdir(void)
{
char *path;
struct inode *ip;
if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0)
return -1;
iunlockput(ip);
return 0;
}
int
sys_chdir(void)
{