?? namei.c
字號:
}
if (offset < sb->sv_block_size)
continue;
brelse(bh);
bh = NULL;
offset = 0; block++;
}
brelse(bh);
return 1;
bad_dir:
brelse(bh);
printk("Bad directory on device %04x\n",inode->i_dev);
return 1;
}
int sysv_rmdir(struct inode * dir, const char * name, int len)
{
int retval;
struct inode * inode;
struct buffer_head * bh;
struct sysv_dir_entry * de;
inode = NULL;
bh = sysv_find_entry(dir,name,len,&de);
retval = -ENOENT;
if (!bh)
goto end_rmdir;
retval = -EPERM;
if (!(inode = iget(dir->i_sb, de->inode)))
goto end_rmdir;
if ((dir->i_mode & S_ISVTX) && current->euid &&
inode->i_uid != current->euid)
goto end_rmdir;
if (inode->i_dev != dir->i_dev)
goto end_rmdir;
if (inode == dir) /* we may not delete ".", but "../dir" is ok */
goto end_rmdir;
if (!S_ISDIR(inode->i_mode)) {
retval = -ENOTDIR;
goto end_rmdir;
}
if (!empty_dir(inode)) {
retval = -ENOTEMPTY;
goto end_rmdir;
}
if (de->inode != inode->i_ino) {
retval = -ENOENT;
goto end_rmdir;
}
if (inode->i_count > 1) {
retval = -EBUSY;
goto end_rmdir;
}
if (inode->i_nlink != 2)
printk("empty directory has nlink!=2 (%d)\n",inode->i_nlink);
de->inode = 0;
bh->b_dirt = 1;
inode->i_nlink=0;
inode->i_dirt=1;
dir->i_nlink--;
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->i_dirt=1;
retval = 0;
end_rmdir:
iput(dir);
iput(inode);
brelse(bh);
return retval;
}
int sysv_unlink(struct inode * dir, const char * name, int len)
{
int retval;
struct inode * inode;
struct buffer_head * bh;
struct sysv_dir_entry * de;
repeat:
retval = -ENOENT;
inode = NULL;
bh = sysv_find_entry(dir,name,len,&de);
if (!bh)
goto end_unlink;
if (!(inode = iget(dir->i_sb, de->inode)))
goto end_unlink;
retval = -EPERM;
if (S_ISDIR(inode->i_mode))
goto end_unlink;
if (de->inode != inode->i_ino) {
iput(inode);
brelse(bh);
current->counter = 0;
schedule();
goto repeat;
}
if ((dir->i_mode & S_ISVTX) && !suser() &&
current->euid != inode->i_uid &&
current->euid != dir->i_uid)
goto end_unlink;
if (de->inode != inode->i_ino) {
retval = -ENOENT;
goto end_unlink;
}
if (!inode->i_nlink) {
printk("Deleting nonexistent file (%04x:%lu), %d\n",
inode->i_dev,inode->i_ino,inode->i_nlink);
inode->i_nlink=1;
}
de->inode = 0;
bh->b_dirt = 1;
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
dir->i_dirt = 1;
inode->i_nlink--;
inode->i_ctime = dir->i_ctime;
inode->i_dirt = 1;
retval = 0;
end_unlink:
brelse(bh);
iput(inode);
iput(dir);
return retval;
}
int sysv_symlink(struct inode * dir, const char * name, int len, const char * symname)
{
struct sysv_dir_entry * de;
struct inode * inode;
struct buffer_head * name_block;
char * name_block_data;
struct super_block * sb;
int i;
char c;
struct buffer_head * bh;
if (!(inode = sysv_new_inode(dir))) {
iput(dir);
return -ENOSPC;
}
inode->i_mode = S_IFLNK | 0777;
inode->i_op = &sysv_symlink_inode_operations;
name_block = sysv_file_bread(inode,0,1,&name_block_data);
if (!name_block) {
iput(dir);
inode->i_nlink--;
inode->i_dirt = 1;
iput(inode);
return -ENOSPC;
}
sb = inode->i_sb;
i = 0;
while (i < sb->sv_block_size_1 && (c = *(symname++)))
name_block_data[i++] = c;
name_block_data[i] = 0;
name_block->b_dirt = 1;
brelse(name_block);
inode->i_size = i;
inode->i_dirt = 1;
bh = sysv_find_entry(dir,name,len,&de);
if (bh) {
inode->i_nlink--;
inode->i_dirt = 1;
iput(inode);
brelse(bh);
iput(dir);
return -EEXIST;
}
i = sysv_add_entry(dir, name, len, &bh, &de);
if (i) {
inode->i_nlink--;
inode->i_dirt = 1;
iput(inode);
iput(dir);
return i;
}
de->inode = inode->i_ino;
bh->b_dirt = 1;
brelse(bh);
iput(dir);
iput(inode);
return 0;
}
int sysv_link(struct inode * oldinode, struct inode * dir, const char * name, int len)
{
int error;
struct sysv_dir_entry * de;
struct buffer_head * bh;
if (S_ISDIR(oldinode->i_mode)) {
iput(oldinode);
iput(dir);
return -EPERM;
}
if (oldinode->i_nlink >= oldinode->i_sb->sv_link_max) {
iput(oldinode);
iput(dir);
return -EMLINK;
}
bh = sysv_find_entry(dir,name,len,&de);
if (bh) {
brelse(bh);
iput(dir);
iput(oldinode);
return -EEXIST;
}
error = sysv_add_entry(dir, name, len, &bh, &de);
if (error) {
iput(dir);
iput(oldinode);
return error;
}
de->inode = oldinode->i_ino;
bh->b_dirt = 1;
brelse(bh);
iput(dir);
oldinode->i_nlink++;
oldinode->i_ctime = CURRENT_TIME;
oldinode->i_dirt = 1;
iput(oldinode);
return 0;
}
/* return 1 if `new' is a subdir of `old' on the same device */
static int subdir(struct inode * new_inode, struct inode * old_inode)
{
int ino;
int result;
new_inode->i_count++;
result = 0;
for (;;) {
if (new_inode == old_inode) {
result = 1;
break;
}
if (new_inode->i_dev != old_inode->i_dev)
break;
ino = new_inode->i_ino;
if (sysv_lookup(new_inode,"..",2,&new_inode))
break;
if (new_inode->i_ino == ino) /* root dir reached ? */
break;
}
iput(new_inode);
return result;
}
#define PARENT_INO(buffer) \
(((struct sysv_dir_entry *) ((buffer) + 1*SYSV_DIRSIZE))->inode)
/*
* rename uses retrying to avoid race-conditions: at least they should be minimal.
* it tries to allocate all the blocks, then sanity-checks, and if the sanity-
* checks fail, it tries to restart itself again. Very practical - no changes
* are done until we know everything works ok.. and then all the changes can be
* done in one fell swoop when we have claimed all the buffers needed.
*
* Anybody can rename anything with this: the permission checks are left to the
* higher-level routines.
*/
static int do_sysv_rename(struct inode * old_dir, const char * old_name, int old_len,
struct inode * new_dir, const char * new_name, int new_len)
{
struct inode * old_inode, * new_inode;
struct buffer_head * old_bh, * new_bh, * dir_bh;
char * dir_bh_data;
struct sysv_dir_entry * old_de, * new_de;
int retval;
goto start_up;
try_again:
brelse(old_bh);
brelse(new_bh);
brelse(dir_bh);
iput(old_inode);
iput(new_inode);
current->counter = 0;
schedule();
start_up:
old_inode = new_inode = NULL;
old_bh = new_bh = dir_bh = NULL;
old_bh = sysv_find_entry(old_dir,old_name,old_len,&old_de);
retval = -ENOENT;
if (!old_bh)
goto end_rename;
old_inode = __iget(old_dir->i_sb, old_de->inode, 0); /* don't cross mnt-points */
if (!old_inode)
goto end_rename;
retval = -EPERM;
if ((old_dir->i_mode & S_ISVTX) &&
current->euid != old_inode->i_uid &&
current->euid != old_dir->i_uid && !suser())
goto end_rename;
new_bh = sysv_find_entry(new_dir,new_name,new_len,&new_de);
if (new_bh) {
new_inode = __iget(new_dir->i_sb, new_de->inode, 0);
if (!new_inode) {
brelse(new_bh);
new_bh = NULL;
}
}
if (new_inode == old_inode) {
retval = 0;
goto end_rename;
}
if (new_inode && S_ISDIR(new_inode->i_mode)) {
retval = -EISDIR;
if (!S_ISDIR(old_inode->i_mode))
goto end_rename;
retval = -EINVAL;
if (subdir(new_dir, old_inode))
goto end_rename;
retval = -ENOTEMPTY;
if (!empty_dir(new_inode))
goto end_rename;
retval = -EBUSY;
if (new_inode->i_count > 1)
goto end_rename;
}
retval = -EPERM;
if (new_inode && (new_dir->i_mode & S_ISVTX) &&
current->euid != new_inode->i_uid &&
current->euid != new_dir->i_uid && !suser())
goto end_rename;
if (S_ISDIR(old_inode->i_mode)) {
retval = -ENOTDIR;
if (new_inode && !S_ISDIR(new_inode->i_mode))
goto end_rename;
retval = -EINVAL;
if (subdir(new_dir, old_inode))
goto end_rename;
retval = -EIO;
dir_bh = sysv_file_bread(old_inode,0,0,&dir_bh_data);
if (!dir_bh)
goto end_rename;
if (PARENT_INO(dir_bh_data) != old_dir->i_ino)
goto end_rename;
retval = -EMLINK;
if (!new_inode && new_dir->i_nlink >= new_dir->i_sb->sv_link_max)
goto end_rename;
}
if (!new_bh) {
retval = sysv_add_entry(new_dir,new_name,new_len,&new_bh,&new_de);
if (retval)
goto end_rename;
}
/* sanity checking before doing the rename - avoid races */
if (new_inode && (new_de->inode != new_inode->i_ino))
goto try_again;
if (new_de->inode && !new_inode)
goto try_again;
if (old_de->inode != old_inode->i_ino)
goto try_again;
/* ok, that's it */
old_de->inode = 0;
new_de->inode = old_inode->i_ino;
old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME;
old_dir->i_dirt = 1;
new_dir->i_ctime = new_dir->i_mtime = CURRENT_TIME;
new_dir->i_dirt = 1;
if (new_inode) {
new_inode->i_nlink--;
new_inode->i_ctime = CURRENT_TIME;
new_inode->i_dirt = 1;
}
old_bh->b_dirt = 1;
new_bh->b_dirt = 1;
if (dir_bh) {
PARENT_INO(dir_bh_data) = new_dir->i_ino;
dir_bh->b_dirt = 1;
old_dir->i_nlink--;
old_dir->i_dirt = 1;
if (new_inode) {
new_inode->i_nlink--;
new_inode->i_dirt = 1;
} else {
new_dir->i_nlink++;
new_dir->i_dirt = 1;
}
}
retval = 0;
end_rename:
brelse(dir_bh);
brelse(old_bh);
brelse(new_bh);
iput(old_inode);
iput(new_inode);
iput(old_dir);
iput(new_dir);
return retval;
}
/*
* Ok, rename also locks out other renames, as they can change the parent of
* a directory, and we don't want any races. Other races are checked for by
* "do_rename()", which restarts if there are inconsistencies.
*
* Note that there is no race between different filesystems: it's only within
* the same device that races occur: many renames can happen at once, as long
* as they are on different partitions.
*/
int sysv_rename(struct inode * old_dir, const char * old_name, int old_len,
struct inode * new_dir, const char * new_name, int new_len)
{
static struct wait_queue * wait = NULL;
static int lock = 0;
int result;
while (lock)
sleep_on(&wait);
lock = 1;
result = do_sysv_rename(old_dir, old_name, old_len,
new_dir, new_name, new_len);
lock = 0;
wake_up(&wait);
return result;
}
?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -