inode addrs[NDIRECT] -> NADDRS

fix race in mknod / creat
use last component in dirent in mknod, not path
This commit is contained in:
rtm 2006-08-25 01:11:30 +00:00
parent 74493bf446
commit 5051da6de3
7 changed files with 208 additions and 31 deletions

5
Notes
View file

@ -120,6 +120,11 @@ test: dup() shared fd->off
test: indirect blocks. files and directories.
test: sbrk
test: does echo foo > x truncate x?
test: does create/mkdir/link extract last component correctly?
does namei insist that all the intermediate directories exist?
test: creat/link/mkdir w/ / in name
test: try to create dir ents when intermediate dir doesn't exist
or is a file, not a dir
make proc[0] runnable
cpu early tss and gdt

3
defs.h
View file

@ -119,11 +119,12 @@ void iunlock(struct inode *ip);
void idecref(struct inode *ip);
void iincref(struct inode *ip);
void iput(struct inode *ip);
struct inode * namei(char *path, int, uint *);
struct inode * namei(char *path, int, uint *, char **, struct inode **);
void stati(struct inode *ip, struct stat *st);
int readi(struct inode *ip, char *xdst, uint off, uint n);
int writei(struct inode *ip, char *addr, uint off, uint n);
struct inode *mknod(char *, short, short, short);
struct inode * mknod1(struct inode *, char *, short, short, short);
int unlink(char *cp);
void iupdate (struct inode *ip);
int link(char *file1, char *file2);

71
fs.c
View file

@ -241,12 +241,14 @@ bmap(struct inode *ip, uint bn)
if (x == 0)
panic("bmap 2");
} else {
if(ip->addrs[INDIRECT] == 0)
panic("bmap 3");
inbp = bread(ip->dev, ip->addrs[INDIRECT]);
a = (uint *) inbp->data;
x = a[bn - NDIRECT];
brelse(inbp);
if (x == 0)
panic("bmap 3");
panic("bmap 4");
}
return x;
}
@ -431,11 +433,14 @@ writei(struct inode *ip, char *addr, uint off, uint n)
// look up a path name, in one of three modes.
// NAMEI_LOOKUP: return locked target inode.
// NAMEI_CREATE: return locked parent inode.
// but return 0 if name does exist.
// return 0 if name does exist.
// *ret_last points to last path component (i.e. new file name).
// *ret_ip points to the the name that did exist, if it did.
// *ret_ip and *ret_last may be zero even if return value is zero.
// NAMEI_DELETE: return locked parent inode, offset of dirent in *ret_off.
// return 0 if name doesn't exist.
struct inode *
namei(char *path, int mode, uint *ret_off)
namei(char *path, int mode, uint *ret_off, char **ret_last, struct inode **ret_ip)
{
struct inode *dp;
struct proc *p = curproc[cpu()];
@ -446,6 +451,17 @@ namei(char *path, int mode, uint *ret_off)
int i, atend;
unsigned ninum;
if(mode == NAMEI_DELETE && ret_off == 0)
panic("namei no ret_off");
if(mode == NAMEI_CREATE && ret_last == 0)
panic("namei no ret_last");
if(ret_off)
*ret_off = 0xffffffff;
if(ret_last)
*ret_last = 0;
if(ret_ip)
*ret_ip = 0;
if (*cp == '/') dp = iget(rootdev, 1);
else {
dp = p->cwd;
@ -460,6 +476,10 @@ namei(char *path, int mode, uint *ret_off)
if(*cp == '\0'){
if(mode == NAMEI_LOOKUP)
return dp;
if(mode == NAMEI_CREATE && ret_ip){
*ret_ip = dp;
return 0;
}
iput(dp);
return 0;
}
@ -493,8 +513,14 @@ namei(char *path, int mode, uint *ret_off)
for(cp1 = cp; *cp1; cp1++)
if(*cp1 == '/')
atend = 0;
if(mode == NAMEI_CREATE && atend)
if(mode == NAMEI_CREATE && atend){
if(*cp == '\0'){
iput(dp);
return 0;
}
*ret_last = cp;
return dp;
}
iput(dp);
return 0;
@ -521,6 +547,9 @@ wdir(struct inode *dp, char *name, uint ino)
struct dirent de;
int i;
if(name[0] == '\0')
panic("wdir no name");
for(off = 0; off < dp->size; off += sizeof(de)){
if(readi(dp, (char *) &de, off, sizeof(de)) != sizeof(de))
panic("wdir read");
@ -529,8 +558,11 @@ wdir(struct inode *dp, char *name, uint ino)
}
de.inum = ino;
for(i = 0; i < DIRSIZ && name[i]; i++)
for(i = 0; i < DIRSIZ && name[i]; i++){
if(name[i] == '/')
panic("wdir /");
de.name[i] = name[i];
}
for( ; i < DIRSIZ; i++)
de.name[i] = '\0';
@ -542,10 +574,23 @@ struct inode *
mknod(char *cp, short type, short major, short minor)
{
struct inode *ip, *dp;
char *last;
if ((dp = namei(cp, NAMEI_CREATE, 0)) == 0)
if ((dp = namei(cp, NAMEI_CREATE, 0, &last, 0)) == 0)
return 0;
ip = mknod1(dp, last, type, major, minor);
iput(dp);
return ip;
}
struct inode *
mknod1(struct inode *dp, char *name, short type, short major, short minor)
{
struct inode *ip;
ip = ialloc(dp->dev, type);
if (ip == 0) {
iput(dp);
@ -558,8 +603,8 @@ mknod(char *cp, short type, short major, short minor)
iupdate (ip); // write new inode to disk
wdir(dp, cp, ip->inum);
iput(dp);
wdir(dp, name, ip->inum);
return ip;
}
@ -570,7 +615,8 @@ unlink(char *cp)
struct dirent de;
uint off, inum, dev;
if ((dp = namei(cp, NAMEI_DELETE, &off)) == 0)
dp = namei(cp, NAMEI_DELETE, &off, 0, 0);
if(dp == 0)
return -1;
dev = dp->dev;
@ -604,8 +650,9 @@ int
link(char *name1, char *name2)
{
struct inode *ip, *dp;
char *last;
if ((ip = namei(name1, NAMEI_LOOKUP, 0)) == 0)
if ((ip = namei(name1, NAMEI_LOOKUP, 0, 0, 0)) == 0)
return -1;
if(ip->type == T_DIR){
iput(ip);
@ -614,7 +661,7 @@ link(char *name1, char *name2)
iunlock(ip);
if ((dp = namei(name2, NAMEI_CREATE, 0)) == 0) {
if ((dp = namei(name2, NAMEI_CREATE, 0, &last, 0)) == 0) {
idecref(ip);
return -1;
}
@ -628,7 +675,7 @@ link(char *name1, char *name2)
ip->nlink += 1;
iupdate (ip);
wdir(dp, name2, ip->inum);
wdir(dp, last, ip->inum);
iput(dp);
iput(ip);

2
fs.h
View file

@ -9,7 +9,7 @@ struct superblock{
uint ninodes;
};
#define NADDRS NDIRECT+1
#define NADDRS (NDIRECT+1)
#define NDIRECT 12
#define INDIRECT 12
#define NINDIRECT (BSIZE / sizeof(uint))

122
fstests.c
View file

@ -213,7 +213,7 @@ unlinkread()
exit();
}
fd1 = open("xxx", O_CREATE | O_RDWR);
fd1 = open("unlinkread", O_CREATE | O_RDWR);
write(fd1, "yyy", 3);
close(fd1);
@ -230,7 +230,7 @@ unlinkread()
exit();
}
close(fd);
unlink("xxx");
unlink("unlinkread");
puts("unlinkread ok\n");
}
@ -319,7 +319,7 @@ concreate()
} else {
fd = open(file, O_CREATE | O_RDWR);
if(fd < 0){
puts("concreate create failed\n");
printf(1, "concreate create %s failed\n", file);
exit();
}
close(fd);
@ -409,12 +409,126 @@ bigdir()
puts("bigdir ok\n");
}
void
subdir()
{
int fd;
if(mkdir("dd") != 0){
puts("subdir mkdir dd failed\n");
exit();
}
fd = open("dd/ff", O_CREATE | O_RDWR);
if(fd < 0){
puts("create dd/ff failed\n");
exit();
}
write(fd, "ff", 2);
close(fd);
if(mkdir("/dd/dd") != 0){
puts("subdir mkdir dd/dd failed\n");
exit();
}
fd = open("dd/dd/ff", O_CREATE | O_RDWR);
if(fd < 0){
puts("create dd/dd/ff failed\n");
exit();
}
write(fd, "FF", 2);
close(fd);
if(link("dd/dd/ff", "dd/dd/ffff") != 0){
puts("link dd/dd/ff dd/dd/ffff failed\n");
exit();
}
if(unlink("dd/dd/ff") != 0){
puts("unlink dd/dd/ff failed\n");
exit();
}
fd = open("dd/dd/ffff", 0);
if(fd < 0){
puts("open dd/dd/ffff failed\n");
exit();
}
if(read(fd, buf, sizeof(buf)) != 2){
puts("read dd/dd/ffff wrong len\n");
exit();
}
close(fd);
if(open("dd/dd/ff", 0) >= 0){
puts("open dd/dd/ff succeeded!\n");
exit();
}
if(open("dd/ff/ff", O_CREATE|O_RDWR) >= 0){
puts("create dd/ff/ff succeeded!\n");
exit();
}
if(open("dd/xx/ff", O_CREATE|O_RDWR) >= 0){
puts("create dd/xx/ff succeeded!\n");
exit();
}
if(link("dd/ff/ff", "dd/dd/xx") == 0){
puts("link dd/ff/ff dd/dd/xx succeeded!\n");
exit();
}
if(link("dd/xx/ff", "dd/dd/xx") == 0){
puts("link dd/xx/ff dd/dd/xx succeeded!\n");
exit();
}
if(link("dd/ff", "dd/dd/ff") == 0){
puts("link dd/ff dd/dd/ff succeeded!\n");
exit();
}
if(mkdir("dd/ff/ff") == 0){
puts("mkdir dd/ff/ff succeeded!\n");
exit();
}
if(mkdir("dd/xx/ff") == 0){
puts("mkdir dd/xx/ff succeeded!\n");
exit();
}
if(mkdir("dd/dd/ff") == 0){
puts("mkdir dd/dd/ff succeeded!\n");
exit();
}
if(unlink("dd/xx/ff") == 0){
puts("unlink dd/xx/ff succeeded!\n");
exit();
}
if(unlink("dd/ff/ff") == 0){
puts("unlink dd/ff/ff succeeded!\n");
exit();
}
if(unlink("dd/dd/ff") != 0){
puts("unlink dd/dd/ff failed\n");
exit();
}
if(unlink("dd/ff") != 0){
puts("unlink dd/ff failed\n");
exit();
}
// unlink dd/dd
// unlink dd
puts("subdir ok\n");
}
int
main(int argc, char *argv[])
{
puts("fstests starting\n");
bigdir();
subdir();
// bigdir(); // slow
concreate();
linktest();
unlinkread();

View file

@ -10,7 +10,7 @@ struct inode {
short minor;
short nlink;
uint size;
uint addrs[NDIRECT];
uint addrs[NADDRS];
};
extern uint rootdev;

View file

@ -219,24 +219,34 @@ int
sys_open(void)
{
struct proc *cp = curproc[cpu()];
struct inode *ip;
struct inode *ip, *dp;
uint arg0, arg1;
int ufd;
struct fd *fd;
int l;
char *last;
if(fetcharg(0, &arg0) < 0 || fetcharg(1, &arg1) < 0)
return -1;
if((l = checkstring(arg0)) < 0)
return -1;
if((ip = namei(cp->mem + arg0, NAMEI_LOOKUP, 0)) == 0) {
if (arg1 & O_CREATE) {
if (l >= DIRSIZ)
return -1;
ip = mknod (cp->mem + arg0, T_FILE, 0, 0);
if (ip == 0) return -1;
} else return -1;
if(arg1 & O_CREATE){
dp = namei(cp->mem + arg0, NAMEI_CREATE, 0, &last, &ip);
if(dp){
ip = mknod1(dp, last, T_FILE, 0, 0);
iput(dp);
if(ip == 0)
return -1;
} else if(ip == 0){
return -1;
}
} else {
ip = namei(cp->mem + arg0, NAMEI_LOOKUP, 0, 0, 0);
if(ip == 0)
return -1;
}
if((fd = fd_alloc()) == 0){
iput(ip);
return -1;
@ -316,7 +326,7 @@ sys_mkdir(void)
de.inum = nip->inum;
writei (nip, (char *) &de, 0, sizeof(de));
pip = namei(".", NAMEI_LOOKUP, 0);
pip = namei(".", NAMEI_LOOKUP, 0, 0, 0);
de.inum = pip->inum;
de.name[1] = '.';
iput(pip);
@ -344,7 +354,7 @@ sys_chdir(void)
if(l >= DIRSIZ)
return -1;
if ((ip = namei(cp->mem + arg0, NAMEI_LOOKUP, 0)) == 0)
if ((ip = namei(cp->mem + arg0, NAMEI_LOOKUP, 0, 0, 0)) == 0)
return -1;
if (ip == cp->cwd) {
@ -475,7 +485,7 @@ sys_exec(void)
return -1;
if(checkstring(arg0) < 0)
return -1;
ip = namei(cp->mem + arg0, NAMEI_LOOKUP, 0);
ip = namei(cp->mem + arg0, NAMEI_LOOKUP, 0, 0, 0);
if(ip == 0)
return -1;