gems-kernel/source/THIRDPARTY/linux-old/fs/msdos/namei.c
2024-06-03 11:16:15 -05:00

592 lines
15 KiB
C

/*
* linux/fs/msdos/namei.c
*
* Written 1992,1993 by Werner Almesberger
*/
#include <asm/segment.h>
#include <linux/sched.h>
#include <linux/msdos_fs.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/stat.h>
/* MS-DOS "device special files" */
static char *reserved_names[] = {
"CON ","PRN ","NUL ","AUX ",
"LPT1 ","LPT2 ","LPT3 ","LPT4 ",
"COM1 ","COM2 ","COM3 ","COM4 ",
NULL };
/* Characters that are undesirable in an MS-DOS file name */
static char bad_chars[] = "*?<>|\"";
static char bad_if_strict[] = "+=,; ";
/* Formats an MS-DOS file name. Rejects invalid names. */
static int msdos_format_name(char conv,const char *name,int len,char *res,
int dot_dirs)
{
char *walk,**reserved;
unsigned char c;
int space;
if (IS_FREE(name)) return -EINVAL;
if (name[0] == '.' && (len == 1 || (len == 2 && name[1] == '.'))) {
if (!dot_dirs) return -EEXIST;
memset(res+1,' ',10);
while (len--) *res++ = '.';
return 0;
}
space = 1; /* disallow names starting with a dot */
c = 0;
for (walk = res; len && walk-res < 8; walk++) {
c = *name++;
len--;
if (conv != 'r' && strchr(bad_chars,c)) return -EINVAL;
if (conv == 's' && strchr(bad_if_strict,c)) return -EINVAL;
if (c >= 'A' && c <= 'Z' && conv == 's') return -EINVAL;
if (c < ' ' || c == ':' || c == '\\') return -EINVAL;
if (c == '.') break;
space = c == ' ';
*walk = c >= 'a' && c <= 'z' ? c-32 : c;
}
if (space) return -EINVAL;
if (conv == 's' && len && c != '.') {
c = *name++;
len--;
if (c != '.') return -EINVAL;
}
while (c != '.' && len--) c = *name++;
if (c == '.') {
while (walk-res < 8) *walk++ = ' ';
while (len > 0 && walk-res < MSDOS_NAME) {
c = *name++;
len--;
if (conv != 'r' && strchr(bad_chars,c)) return -EINVAL;
if (conv == 's' && strchr(bad_if_strict,c))
return -EINVAL;
if (c < ' ' || c == ':' || c == '\\' || c == '.')
return -EINVAL;
if (c >= 'A' && c <= 'Z' && conv == 's') return -EINVAL;
space = c == ' ';
*walk++ = c >= 'a' && c <= 'z' ? c-32 : c;
}
if (space) return -EINVAL;
if (conv == 's' && len) return -EINVAL;
}
while (walk-res < MSDOS_NAME) *walk++ = ' ';
for (reserved = reserved_names; *reserved; reserved++)
if (!strncmp(res,*reserved,8)) return -EINVAL;
return 0;
}
/* Locates a directory entry. */
static int msdos_find(struct inode *dir,const char *name,int len,
struct buffer_head **bh,struct msdos_dir_entry **de,int *ino)
{
char msdos_name[MSDOS_NAME];
int res;
if ((res = msdos_format_name(MSDOS_SB(dir->i_sb)->name_check,name,len,
msdos_name,1)) < 0) return res;
return msdos_scan(dir,msdos_name,bh,de,ino);
}
int msdos_lookup(struct inode *dir,const char *name,int len,
struct inode **result)
{
int ino,res;
struct msdos_dir_entry *de;
struct buffer_head *bh;
struct inode *next;
*result = NULL;
if (!dir) return -ENOENT;
if (!S_ISDIR(dir->i_mode)) {
iput(dir);
return -ENOENT;
}
if (len == 1 && name[0] == '.') {
*result = dir;
return 0;
}
if (len == 2 && name[0] == '.' && name[1] == '.') {
ino = msdos_parent_ino(dir,0);
iput(dir);
if (ino < 0) return ino;
if (!(*result = iget(dir->i_sb,ino))) return -EACCES;
return 0;
}
if ((res = msdos_find(dir,name,len,&bh,&de,&ino)) < 0) {
iput(dir);
return res;
}
if (bh) brelse(bh);
/* printk("lookup: ino=%d\n",ino); */
if (!(*result = iget(dir->i_sb,ino))) {
iput(dir);
return -EACCES;
}
if (MSDOS_I(*result)->i_busy) { /* mkdir in progress */
iput(*result);
iput(dir);
return -ENOENT;
}
while (MSDOS_I(*result)->i_old) {
next = MSDOS_I(*result)->i_old;
iput(*result);
if (!(*result = iget(next->i_sb,next->i_ino))) {
fs_panic(dir->i_sb,"msdos_lookup: Can't happen");
iput(dir);
return -ENOENT;
}
}
iput(dir);
return 0;
}
/* Creates a directory entry (name is already formatted). */
static int msdos_create_entry(struct inode *dir,char *name,int is_dir,
struct inode **result)
{
struct buffer_head *bh;
struct msdos_dir_entry *de;
int res,ino;
if ((res = msdos_scan(dir,NULL,&bh,&de,&ino)) < 0) {
if (res != -ENOENT) return res;
if (dir->i_ino == MSDOS_ROOT_INO) return -ENOSPC;
if ((res = msdos_add_cluster(dir)) < 0) return res;
if ((res = msdos_scan(dir,NULL,&bh,&de,&ino)) < 0) return res;
}
/*
* XXX all times should be set by caller upon successful completion.
*/
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->i_dirt = 1;
memcpy(de->name,name,MSDOS_NAME);
de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
de->start = 0;
date_unix2dos(dir->i_mtime,&de->time,&de->date);
de->size = 0;
bh->b_dirt = 1;
if ((*result = iget(dir->i_sb,ino)) != NULL)
msdos_read_inode(*result);
brelse(bh);
if (!*result) return -EIO;
(*result)->i_mtime = (*result)->i_atime = (*result)->i_ctime =
CURRENT_TIME;
(*result)->i_dirt = 1;
return 0;
}
int msdos_create(struct inode *dir,const char *name,int len,int mode,
struct inode **result)
{
struct buffer_head *bh;
struct msdos_dir_entry *de;
char msdos_name[MSDOS_NAME];
int ino,res;
if (!dir) return -ENOENT;
if ((res = msdos_format_name(MSDOS_SB(dir->i_sb)->name_check,name,len,
msdos_name,0)) < 0) {
iput(dir);
return res;
}
lock_creation();
if (msdos_scan(dir,msdos_name,&bh,&de,&ino) >= 0) {
unlock_creation();
brelse(bh);
iput(dir);
return -EEXIST;
}
res = msdos_create_entry(dir,msdos_name,S_ISDIR(mode),result);
unlock_creation();
iput(dir);
return res;
}
#ifdef DEBUG
static void dump_fat(struct super_block *sb,int start)
{
printk("[");
while (start) {
printk("%d ",start);
start = fat_access(sb,start,-1);
if (!start) {
printk("ERROR");
break;
}
if (start == -1) break;
}
printk("]\n");
}
#endif
int msdos_mkdir(struct inode *dir,const char *name,int len,int mode)
{
struct buffer_head *bh;
struct msdos_dir_entry *de;
struct inode *inode,*dot;
char msdos_name[MSDOS_NAME];
int ino,res;
if ((res = msdos_format_name(MSDOS_SB(dir->i_sb)->name_check,name,len,
msdos_name,0)) < 0) {
iput(dir);
return res;
}
lock_creation();
if (msdos_scan(dir,msdos_name,&bh,&de,&ino) >= 0) {
unlock_creation();
brelse(bh);
iput(dir);
return -EEXIST;
}
if ((res = msdos_create_entry(dir,msdos_name,1,&inode)) < 0) {
unlock_creation();
iput(dir);
return res;
}
dir->i_nlink++;
inode->i_nlink = 2; /* no need to mark them dirty */
MSDOS_I(inode)->i_busy = 1; /* prevent lookups */
if ((res = msdos_add_cluster(inode)) < 0) goto mkdir_error;
if ((res = msdos_create_entry(inode,MSDOS_DOT,1,&dot)) < 0)
goto mkdir_error;
dot->i_size = inode->i_size; /* doesn't grow in the 2nd create_entry */
MSDOS_I(dot)->i_start = MSDOS_I(inode)->i_start;
dot->i_nlink = inode->i_nlink;
dot->i_dirt = 1;
iput(dot);
if ((res = msdos_create_entry(inode,MSDOS_DOTDOT,1,&dot)) < 0)
goto mkdir_error;
unlock_creation();
dot->i_size = dir->i_size;
MSDOS_I(dot)->i_start = MSDOS_I(dir)->i_start;
dot->i_nlink = dir->i_nlink;
dot->i_dirt = 1;
MSDOS_I(inode)->i_busy = 0;
iput(dot);
iput(inode);
iput(dir);
return 0;
mkdir_error:
iput(inode);
if (msdos_rmdir(dir,name,len) < 0)
fs_panic(dir->i_sb,"rmdir in mkdir failed");
unlock_creation();
return res;
}
static int msdos_empty(struct inode *dir)
{
off_t pos;
struct buffer_head *bh;
struct msdos_dir_entry *de;
if (dir->i_count > 1)
return -EBUSY;
if (MSDOS_I(dir)->i_start) { /* may be zero in mkdir */
pos = 0;
bh = NULL;
while (msdos_get_entry(dir,&pos,&bh,&de) > -1)
if (!IS_FREE(de->name) && strncmp(de->name,MSDOS_DOT,
MSDOS_NAME) && strncmp(de->name,MSDOS_DOTDOT,
MSDOS_NAME)) {
brelse(bh);
return -ENOTEMPTY;
}
if (bh)
brelse(bh);
}
return 0;
}
int msdos_rmdir(struct inode *dir,const char *name,int len)
{
int res,ino;
struct buffer_head *bh;
struct msdos_dir_entry *de;
struct inode *inode;
bh = NULL;
inode = NULL;
res = -EPERM;
if (name[0] == '.' && (len == 1 || (len == 2 && name[1] == '.')))
goto rmdir_done;
if ((res = msdos_find(dir,name,len,&bh,&de,&ino)) < 0) goto rmdir_done;
res = -ENOENT;
if (!(inode = iget(dir->i_sb,ino))) goto rmdir_done;
res = -ENOTDIR;
if (!S_ISDIR(inode->i_mode)) goto rmdir_done;
res = -EBUSY;
if (dir->i_dev != inode->i_dev || dir == inode) goto rmdir_done;
res = msdos_empty(inode);
if (res)
goto rmdir_done;
inode->i_nlink = 0;
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->i_nlink--;
inode->i_dirt = dir->i_dirt = 1;
de->name[0] = DELETED_FLAG;
bh->b_dirt = 1;
res = 0;
rmdir_done:
brelse(bh);
iput(dir);
iput(inode);
return res;
}
int msdos_unlink(struct inode *dir,const char *name,int len)
{
int res,ino;
struct buffer_head *bh;
struct msdos_dir_entry *de;
struct inode *inode;
bh = NULL;
inode = NULL;
if ((res = msdos_find(dir,name,len,&bh,&de,&ino)) < 0)
goto unlink_done;
if (!(inode = iget(dir->i_sb,ino))) {
res = -ENOENT;
goto unlink_done;
}
if (!S_ISREG(inode->i_mode)) {
res = -EPERM;
goto unlink_done;
}
inode->i_nlink = 0;
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
MSDOS_I(inode)->i_busy = 1;
inode->i_dirt = dir->i_dirt = 1;
de->name[0] = DELETED_FLAG;
bh->b_dirt = 1;
unlink_done:
brelse(bh);
iput(inode);
iput(dir);
return res;
}
static int rename_same_dir(struct inode *old_dir,char *old_name,
struct inode *new_dir,char *new_name,struct buffer_head *old_bh,
struct msdos_dir_entry *old_de,int old_ino)
{
struct buffer_head *new_bh;
struct msdos_dir_entry *new_de;
struct inode *new_inode,*old_inode;
int new_ino,exists,error;
if (!strncmp(old_name,new_name,MSDOS_NAME)) return 0;
exists = msdos_scan(new_dir,new_name,&new_bh,&new_de,&new_ino) >= 0;
if (*(unsigned char *) old_de->name == DELETED_FLAG) {
if (exists) brelse(new_bh);
return -ENOENT;
}
if (exists) {
if (!(new_inode = iget(new_dir->i_sb,new_ino))) {
brelse(new_bh);
return -EIO;
}
error = S_ISDIR(new_inode->i_mode) ? (old_de->attr & ATTR_DIR) ?
msdos_empty(new_inode) : -EPERM : (old_de->attr & ATTR_DIR)
? -EPERM : 0;
if (error) {
iput(new_inode);
brelse(new_bh);
return error;
}
if (S_ISDIR(new_inode->i_mode)) {
new_dir->i_nlink--;
new_dir->i_dirt = 1;
}
new_inode->i_nlink = 0;
MSDOS_I(new_inode)->i_busy = 1;
new_inode->i_dirt = 1;
new_de->name[0] = DELETED_FLAG;
new_bh->b_dirt = 1;
iput(new_inode);
brelse(new_bh);
}
memcpy(old_de->name,new_name,MSDOS_NAME);
old_bh->b_dirt = 1;
if (MSDOS_SB(old_dir->i_sb)->conversion == 'a') /* update binary info */
if ((old_inode = iget(old_dir->i_sb,old_ino)) != NULL) {
msdos_read_inode(old_inode);
iput(old_inode);
}
return 0;
}
static int rename_diff_dir(struct inode *old_dir,char *old_name,
struct inode *new_dir,char *new_name,struct buffer_head *old_bh,
struct msdos_dir_entry *old_de,int old_ino)
{
struct buffer_head *new_bh,*free_bh,*dotdot_bh;
struct msdos_dir_entry *new_de,*free_de,*dotdot_de;
struct inode *old_inode,*new_inode,*free_inode,*dotdot_inode,*walk;
int new_ino,free_ino,dotdot_ino;
int error,exists,ino;
if (old_dir->i_dev != new_dir->i_dev) return -EINVAL;
if (old_ino == new_dir->i_ino) return -EINVAL;
if (!(walk = iget(new_dir->i_sb,new_dir->i_ino))) return -EIO;
while (walk->i_ino != MSDOS_ROOT_INO) {
ino = msdos_parent_ino(walk,1);
iput(walk);
if (ino < 0) return ino;
if (ino == old_ino) return -EINVAL;
if (!(walk = iget(new_dir->i_sb,ino))) return -EIO;
}
iput(walk);
while ((error = msdos_scan(new_dir,NULL,&free_bh,&free_de,&free_ino)) <
0) {
if (error != -ENOENT) return error;
error = msdos_add_cluster(new_dir);
if (error) return error;
}
exists = msdos_scan(new_dir,new_name,&new_bh,&new_de,&new_ino) >= 0;
if (!(old_inode = iget(old_dir->i_sb,old_ino))) {
brelse(free_bh);
if (exists) brelse(new_bh);
return -EIO;
}
if (*(unsigned char *) old_de->name == DELETED_FLAG) {
iput(old_inode);
brelse(free_bh);
if (exists) brelse(new_bh);
return -ENOENT;
}
new_inode = NULL; /* to make GCC happy */
if (exists) {
if (!(new_inode = iget(new_dir->i_sb,new_ino))) {
iput(old_inode);
brelse(new_bh);
return -EIO;
}
error = S_ISDIR(new_inode->i_mode) ? (old_de->attr & ATTR_DIR) ?
msdos_empty(new_inode) : -EPERM : (old_de->attr & ATTR_DIR)
? -EPERM : 0;
if (error) {
iput(new_inode);
iput(old_inode);
brelse(new_bh);
return error;
}
new_inode->i_nlink = 0;
MSDOS_I(new_inode)->i_busy = 1;
new_inode->i_dirt = 1;
new_de->name[0] = DELETED_FLAG;
new_bh->b_dirt = 1;
}
memcpy(free_de,old_de,sizeof(struct msdos_dir_entry));
memcpy(free_de->name,new_name,MSDOS_NAME);
if (!(free_inode = iget(new_dir->i_sb,free_ino))) {
free_de->name[0] = DELETED_FLAG;
/* Don't mark free_bh as dirty. Both states are supposed to be equivalent. */
brelse(free_bh);
if (exists) {
iput(new_inode);
brelse(new_bh);
}
return -EIO;
}
if (exists && S_ISDIR(new_inode->i_mode)) {
new_dir->i_nlink--;
new_dir->i_dirt = 1;
}
msdos_read_inode(free_inode);
MSDOS_I(old_inode)->i_busy = 1;
cache_inval_inode(old_inode);
old_inode->i_dirt = 1;
old_de->name[0] = DELETED_FLAG;
old_bh->b_dirt = 1;
free_bh->b_dirt = 1;
if (!exists) iput(free_inode);
else {
MSDOS_I(new_inode)->i_depend = free_inode;
MSDOS_I(free_inode)->i_old = new_inode;
/* free_inode is put when putting new_inode */
iput(new_inode);
brelse(new_bh);
}
if (S_ISDIR(old_inode->i_mode)) {
if ((error = msdos_scan(old_inode,MSDOS_DOTDOT,&dotdot_bh,
&dotdot_de,&dotdot_ino)) < 0) goto rename_done;
if (!(dotdot_inode = iget(old_inode->i_sb,dotdot_ino))) {
brelse(dotdot_bh);
error = -EIO;
goto rename_done;
}
dotdot_de->start = MSDOS_I(dotdot_inode)->i_start =
MSDOS_I(new_dir)->i_start;
dotdot_inode->i_dirt = 1;
dotdot_bh->b_dirt = 1;
old_dir->i_nlink--;
new_dir->i_nlink++;
/* no need to mark them dirty */
dotdot_inode->i_nlink = new_dir->i_nlink;
iput(dotdot_inode);
brelse(dotdot_bh);
}
error = 0;
rename_done:
brelse(free_bh);
iput(old_inode);
return error;
}
int msdos_rename(struct inode *old_dir,const char *old_name,int old_len,
struct inode *new_dir,const char *new_name,int new_len)
{
char old_msdos_name[MSDOS_NAME],new_msdos_name[MSDOS_NAME];
struct buffer_head *old_bh;
struct msdos_dir_entry *old_de;
int old_ino,error;
if ((error = msdos_format_name(MSDOS_SB(old_dir->i_sb)->name_check,
old_name,old_len,old_msdos_name,1)) < 0) goto rename_done;
if ((error = msdos_format_name(MSDOS_SB(new_dir->i_sb)->name_check,
new_name,new_len,new_msdos_name,0)) < 0) goto rename_done;
if ((error = msdos_scan(old_dir,old_msdos_name,&old_bh,&old_de,
&old_ino)) < 0) goto rename_done;
lock_creation();
if (old_dir == new_dir)
error = rename_same_dir(old_dir,old_msdos_name,new_dir,
new_msdos_name,old_bh,old_de,old_ino);
else error = rename_diff_dir(old_dir,old_msdos_name,new_dir,
new_msdos_name,old_bh,old_de,old_ino);
unlock_creation();
brelse(old_bh);
rename_done:
iput(old_dir);
iput(new_dir);
return error;
}