| 1 |
199 |
simons |
/*
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* linux/fs/umsdos/namei.c
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*
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* Written 1993 by Jacques Gelinas
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* Inspired from linux/fs/msdos/... by Werner Almesberger
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*
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* Maintain and access the --linux alternate directory file.
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/types.h>
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#include <linux/fcntl.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/msdos_fs.h>
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#include <linux/umsdos_fs.h>
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#include <linux/malloc.h>
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#define PRINTK(x)
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#define Printk(x) printk x
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#if 1
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/*
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Wait for creation exclusivity.
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Return 0 if the dir was already available.
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Return 1 if a wait was necessary.
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When 1 is return, it means a wait was done. It does not
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mean the directory is available.
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*/
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static int umsdos_waitcreate(struct inode *dir)
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{
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int ret = 0;
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if (dir->u.umsdos_i.u.dir_info.creating
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&& dir->u.umsdos_i.u.dir_info.pid != current->pid){
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sleep_on(&dir->u.umsdos_i.u.dir_info.p);
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ret = 1;
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}
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return ret;
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}
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/*
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Wait for any lookup process to finish
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*/
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static void umsdos_waitlookup (struct inode *dir)
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{
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while (dir->u.umsdos_i.u.dir_info.looking){
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sleep_on(&dir->u.umsdos_i.u.dir_info.p);
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}
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}
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/*
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Lock all other process out of this directory.
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*/
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void umsdos_lockcreate (struct inode *dir)
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{
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/* #Specification: file creation / not atomic
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File creation is a two step process. First we create (allocate)
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an entry in the EMD file and then (using the entry offset) we
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build a unique name for MSDOS. We create this name in the msdos
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space.
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We have to use semaphore (sleep_on/wake_up) to prevent lookup
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into a directory when we create a file or directory and to
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prevent creation while a lookup is going on. Since many lookup
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may happen at the same time, the semaphore is a counter.
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Only one creation is allowed at the same time. This protection
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may not be necessary. The problem arise mainly when a lookup
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or a readdir is done while a file is partially created. The
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lookup process see that as a "normal" problem and silently
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erase the file from the EMD file. Normal because a file
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may be erased during a MSDOS session, but not removed from
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the EMD file.
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The locking is done on a directory per directory basis. Each
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directory inode has its wait_queue.
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For some operation like hard link, things even get worse. Many
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creation must occur at once (atomic). To simplify the design
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a process is allowed to recursively lock the directory for
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creation. The pid of the locking process is kept along with
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a counter so a second level of locking is granted or not.
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*/
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/*
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Wait for any creation process to finish except
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if we (the process) own the lock
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*/
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while (umsdos_waitcreate(dir)!=0);
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dir->u.umsdos_i.u.dir_info.creating++;
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dir->u.umsdos_i.u.dir_info.pid = current->pid;
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umsdos_waitlookup (dir);
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}
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/*
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Lock all other process out of those two directories.
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*/
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static void umsdos_lockcreate2 (struct inode *dir1, struct inode *dir2)
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{
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/*
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We must check that both directory are available before
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locking anyone of them. This is to avoid some deadlock.
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Thanks to dglaude@is1.vub.ac.be (GLAUDE DAVID) for pointing
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this to me.
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*/
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while (1){
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if (umsdos_waitcreate(dir1)==0
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&& umsdos_waitcreate(dir2)==0){
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/* We own both now */
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dir1->u.umsdos_i.u.dir_info.creating++;
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dir1->u.umsdos_i.u.dir_info.pid = current->pid;
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dir2->u.umsdos_i.u.dir_info.creating++;
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dir2->u.umsdos_i.u.dir_info.pid = current->pid;
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break;
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}
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}
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umsdos_waitlookup(dir1);
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umsdos_waitlookup(dir2);
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}
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/*
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Wait until creation is finish in this directory.
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*/
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void umsdos_startlookup (struct inode *dir)
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{
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while (umsdos_waitcreate (dir) != 0);
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dir->u.umsdos_i.u.dir_info.looking++;
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}
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/*
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Unlock the directory.
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*/
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void umsdos_unlockcreate (struct inode *dir)
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{
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dir->u.umsdos_i.u.dir_info.creating--;
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if (dir->u.umsdos_i.u.dir_info.creating < 0){
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printk ("UMSDOS: dir->u.umsdos_i.u.dir_info.creating < 0: %d"
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,dir->u.umsdos_i.u.dir_info.creating);
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}
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wake_up (&dir->u.umsdos_i.u.dir_info.p);
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}
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/*
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Tell directory lookup is over.
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*/
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void umsdos_endlookup (struct inode *dir)
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{
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dir->u.umsdos_i.u.dir_info.looking--;
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if (dir->u.umsdos_i.u.dir_info.looking < 0){
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printk ("UMSDOS: dir->u.umsdos_i.u.dir_info.looking < 0: %d"
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,dir->u.umsdos_i.u.dir_info.looking);
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}
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wake_up (&dir->u.umsdos_i.u.dir_info.p);
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}
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#else
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static void umsdos_lockcreate (struct inode *dir){}
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static void umsdos_lockcreate2 (struct inode *dir1, struct inode *dir2){}
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| 154 |
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void umsdos_startlookup (struct inode *dir){}
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static void umsdos_unlockcreate (struct inode *dir){}
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void umsdos_endlookup (struct inode *dir){}
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#endif
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static int umsdos_nevercreat(
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| 159 |
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struct inode *dir,
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const char *name, /* Name of the file to add */
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int len,
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int errcod) /* Length of the name */
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{
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int ret = 0;
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if (umsdos_is_pseudodos(dir,name,len)){
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/* #Specification: pseudo root / any file creation /DOS
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The pseudo sub-directory /DOS can't be created!
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EEXIST is returned.
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The pseudo sub-directory /DOS can't be removed!
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EPERM is returned.
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*/
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ret = -EPERM;
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ret = errcod;
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}else if (name[0] == '.'
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&& (len == 1 || (len == 2 && name[1] == '.'))){
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/* #Specification: create / . and ..
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If one try to creates . or .., it always fail and return
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EEXIST.
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| 181 |
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If one try to delete . or .., it always fail and return
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| 182 |
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EPERM.
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| 184 |
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This should be test at the VFS layer level to avoid
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duplicating this in all file systems. Any comments ?
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*/
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ret = errcod;
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}
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| 189 |
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return ret;
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| 190 |
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}
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| 191 |
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| 192 |
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/*
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| 193 |
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Add a new file (ordinary or special) into the alternate directory.
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| 194 |
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The file is added to the real MSDOS directory. If successful, it
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is then added to the EDM file.
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| 196 |
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| 197 |
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Return the status of the operation. 0 mean success.
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| 198 |
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*/
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static int umsdos_create_any (
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| 200 |
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struct inode *dir,
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| 201 |
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const char *name, /* Name of the file to add */
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| 202 |
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int len, /* Length of the name */
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| 203 |
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int mode, /* Permission bit + file type ??? */
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| 204 |
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int rdev, /* major, minor or 0 for ordinary file */
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| 205 |
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/* and symlinks */
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| 206 |
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char flags,
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| 207 |
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struct inode **result) /* Will hold the inode of the newly created */
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| 208 |
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/* file */
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| 209 |
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{
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| 210 |
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int ret = umsdos_nevercreat(dir,name,len,-EEXIST);
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| 211 |
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if (ret == 0){
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| 212 |
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struct umsdos_info info;
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| 213 |
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ret = umsdos_parse (name,len,&info);
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| 214 |
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*result = NULL;
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| 215 |
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if (ret == 0){
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| 216 |
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info.entry.mode = mode;
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| 217 |
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info.entry.rdev = rdev;
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| 218 |
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info.entry.flags = flags;
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| 219 |
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info.entry.uid = current->fsuid;
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| 220 |
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info.entry.gid = (dir->i_mode & S_ISGID)
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| 221 |
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? dir->i_gid : current->fsgid;
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| 222 |
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info.entry.ctime = info.entry.atime = info.entry.mtime
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| 223 |
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= CURRENT_TIME;
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| 224 |
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info.entry.nlink = 1;
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| 225 |
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umsdos_lockcreate(dir);
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| 226 |
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ret = umsdos_newentry (dir,&info);
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| 227 |
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if (ret == 0){
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| 228 |
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dir->i_count++;
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| 229 |
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ret = msdos_create (dir,info.fake.fname,info.fake.len
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| 230 |
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,S_IFREG|0777,result);
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| 231 |
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if (ret == 0){
|
| 232 |
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struct inode *inode = *result;
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| 233 |
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umsdos_lookup_patch (dir,inode,&info.entry,info.f_pos);
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| 234 |
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PRINTK (("inode %p[%ld] ",inode,inode->i_count));
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| 235 |
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PRINTK (("Creation OK: [%d] %s %d pos %d\n",dir->i_ino
|
| 236 |
|
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,info.fake.fname,current->pid,info.f_pos));
|
| 237 |
|
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}else{
|
| 238 |
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/* #Specification: create / file exist in DOS
|
| 239 |
|
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Here is a situation. Trying to create a file with
|
| 240 |
|
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UMSDOS. The file is unknown to UMSDOS but already
|
| 241 |
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exist in the DOS directory.
|
| 242 |
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|
| 243 |
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Here is what we are NOT doing:
|
| 244 |
|
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|
| 245 |
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We could silently assume that everything is fine
|
| 246 |
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and allows the creation to succeed.
|
| 247 |
|
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|
| 248 |
|
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It is possible not all files in the partition
|
| 249 |
|
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are mean to be visible from linux. By trying to create
|
| 250 |
|
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those file in some directory, one user may get access
|
| 251 |
|
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to those file without proper permissions. Looks like
|
| 252 |
|
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a security hole to me. Off course sharing a file system
|
| 253 |
|
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with DOS is some kind of security hole :-)
|
| 254 |
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|
|
| 255 |
|
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So ?
|
| 256 |
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|
| 257 |
|
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We return EEXIST in this case.
|
| 258 |
|
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The same is true for directory creation.
|
| 259 |
|
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*/
|
| 260 |
|
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if (ret == -EEXIST){
|
| 261 |
|
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printk ("UMSDOS: out of sync, Creation error [%ld], "
|
| 262 |
|
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"deleting %s %d %d pos %ld\n",dir->i_ino
|
| 263 |
|
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,info.fake.fname,-ret,current->pid,info.f_pos);
|
| 264 |
|
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}
|
| 265 |
|
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umsdos_delentry (dir,&info,0);
|
| 266 |
|
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}
|
| 267 |
|
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PRINTK (("umsdos_create %s ret = %d pos %d\n"
|
| 268 |
|
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,info.fake.fname,ret,info.f_pos));
|
| 269 |
|
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}
|
| 270 |
|
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umsdos_unlockcreate(dir);
|
| 271 |
|
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}
|
| 272 |
|
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}
|
| 273 |
|
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iput (dir);
|
| 274 |
|
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return ret;
|
| 275 |
|
|
}
|
| 276 |
|
|
/*
|
| 277 |
|
|
Initialise the new_entry from the old for a rename operation.
|
| 278 |
|
|
(Only useful for umsdos_rename_f() below).
|
| 279 |
|
|
*/
|
| 280 |
|
|
static void umsdos_ren_init(
|
| 281 |
|
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struct umsdos_info *new_info,
|
| 282 |
|
|
struct umsdos_info *old_info,
|
| 283 |
|
|
int flags) /* 0 == copy flags from old_name */
|
| 284 |
|
|
/* != 0, this is the value of flags */
|
| 285 |
|
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{
|
| 286 |
|
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new_info->entry.mode = old_info->entry.mode;
|
| 287 |
|
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new_info->entry.rdev = old_info->entry.rdev;
|
| 288 |
|
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new_info->entry.uid = old_info->entry.uid;
|
| 289 |
|
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new_info->entry.gid = old_info->entry.gid;
|
| 290 |
|
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new_info->entry.ctime = old_info->entry.ctime;
|
| 291 |
|
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new_info->entry.atime = old_info->entry.atime;
|
| 292 |
|
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new_info->entry.mtime = old_info->entry.mtime;
|
| 293 |
|
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new_info->entry.flags = flags ? flags : old_info->entry.flags;
|
| 294 |
|
|
new_info->entry.nlink = old_info->entry.nlink;
|
| 295 |
|
|
}
|
| 296 |
|
|
|
| 297 |
|
|
#define chkstk() \
|
| 298 |
|
|
if (STACK_MAGIC != *(unsigned long *)current->kernel_stack_page){\
|
| 299 |
|
|
printk(KERN_ALERT "UMSDOS: %s magic %x != %lx ligne %d\n" \
|
| 300 |
|
|
, current->comm,STACK_MAGIC \
|
| 301 |
|
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,*(unsigned long *)current->kernel_stack_page \
|
| 302 |
|
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,__LINE__); \
|
| 303 |
|
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}
|
| 304 |
|
|
|
| 305 |
|
|
/*
|
| 306 |
|
|
Rename a file (move) in the file system.
|
| 307 |
|
|
*/
|
| 308 |
|
|
static int umsdos_rename_f(
|
| 309 |
|
|
struct inode * old_dir,
|
| 310 |
|
|
const char * old_name,
|
| 311 |
|
|
int old_len,
|
| 312 |
|
|
struct inode * new_dir,
|
| 313 |
|
|
const char * new_name,
|
| 314 |
|
|
int new_len,
|
| 315 |
|
|
int flags) /* 0 == copy flags from old_name */
|
| 316 |
|
|
/* != 0, this is the value of flags */
|
| 317 |
|
|
{
|
| 318 |
|
|
int ret = -EPERM;
|
| 319 |
|
|
struct umsdos_info old_info;
|
| 320 |
|
|
int old_ret = umsdos_parse (old_name,old_len,&old_info);
|
| 321 |
|
|
struct umsdos_info new_info;
|
| 322 |
|
|
int new_ret = umsdos_parse (new_name,new_len,&new_info);
|
| 323 |
|
|
chkstk();
|
| 324 |
|
|
PRINTK (("umsdos_rename %d %d ",old_ret,new_ret));
|
| 325 |
|
|
if (old_ret == 0 && new_ret == 0){
|
| 326 |
|
|
umsdos_lockcreate2(old_dir,new_dir);
|
| 327 |
|
|
chkstk();
|
| 328 |
|
|
PRINTK (("old findentry "));
|
| 329 |
|
|
ret = umsdos_findentry(old_dir,&old_info,0);
|
| 330 |
|
|
chkstk();
|
| 331 |
|
|
PRINTK (("ret %d ",ret));
|
| 332 |
|
|
if (ret == 0){
|
| 333 |
|
|
/* check sticky bit on old_dir */
|
| 334 |
|
|
if ( !(old_dir->i_mode & S_ISVTX) || fsuser() ||
|
| 335 |
|
|
current->fsuid == old_info.entry.uid ||
|
| 336 |
|
|
current->fsuid == old_dir->i_uid ) {
|
| 337 |
|
|
/* Does new_name already exist? */
|
| 338 |
|
|
PRINTK(("new findentry "));
|
| 339 |
|
|
ret = umsdos_findentry(new_dir,&new_info,0);
|
| 340 |
|
|
if (ret != 0 || /* if destination file exists, are we allowed to replace it ? */
|
| 341 |
|
|
!(new_dir->i_mode & S_ISVTX) || fsuser() ||
|
| 342 |
|
|
current->fsuid == new_info.entry.uid ||
|
| 343 |
|
|
current->fsuid == new_dir->i_uid ) {
|
| 344 |
|
|
PRINTK (("new newentry "));
|
| 345 |
|
|
umsdos_ren_init(&new_info,&old_info,flags);
|
| 346 |
|
|
ret = umsdos_newentry (new_dir,&new_info);
|
| 347 |
|
|
chkstk();
|
| 348 |
|
|
PRINTK (("ret %d %d ",ret,new_info.fake.len));
|
| 349 |
|
|
if (ret == 0){
|
| 350 |
|
|
PRINTK (("msdos_rename "));
|
| 351 |
|
|
old_dir->i_count++;
|
| 352 |
|
|
new_dir->i_count++; /* Both inode are needed later */
|
| 353 |
|
|
ret = msdos_rename (old_dir
|
| 354 |
|
|
,old_info.fake.fname,old_info.fake.len
|
| 355 |
|
|
,new_dir
|
| 356 |
|
|
,new_info.fake.fname,new_info.fake.len
|
| 357 |
|
|
,0);
|
| 358 |
|
|
chkstk();
|
| 359 |
|
|
PRINTK (("after m_rename ret %d ",ret));
|
| 360 |
|
|
if (ret != 0){
|
| 361 |
|
|
umsdos_delentry (new_dir,&new_info
|
| 362 |
|
|
,S_ISDIR(new_info.entry.mode));
|
| 363 |
|
|
chkstk();
|
| 364 |
|
|
}else{
|
| 365 |
|
|
ret = umsdos_delentry (old_dir,&old_info
|
| 366 |
|
|
,S_ISDIR(old_info.entry.mode));
|
| 367 |
|
|
chkstk();
|
| 368 |
|
|
if (ret == 0){
|
| 369 |
|
|
/*
|
| 370 |
|
|
This UMSDOS_lookup does not look very useful.
|
| 371 |
|
|
It makes sure that the inode of the file will
|
| 372 |
|
|
be correctly setup (umsdos_patch_inode()) in
|
| 373 |
|
|
case it is already in use.
|
| 374 |
|
|
|
| 375 |
|
|
Not very efficient ...
|
| 376 |
|
|
*/
|
| 377 |
|
|
struct inode *inode;
|
| 378 |
|
|
new_dir->i_count++;
|
| 379 |
|
|
PRINTK (("rename lookup len %d %d -- ",new_len,new_info.entry.flags));
|
| 380 |
|
|
ret = UMSDOS_lookup (new_dir,new_name,new_len
|
| 381 |
|
|
,&inode);
|
| 382 |
|
|
chkstk();
|
| 383 |
|
|
if (ret != 0){
|
| 384 |
|
|
printk ("UMSDOS: partial rename for file %s\n"
|
| 385 |
|
|
,new_info.entry.name);
|
| 386 |
|
|
}else{
|
| 387 |
|
|
/*
|
| 388 |
|
|
Update f_pos so notify_change will succeed
|
| 389 |
|
|
if the file was already in use.
|
| 390 |
|
|
*/
|
| 391 |
|
|
umsdos_set_dirinfo (inode,new_dir,new_info.f_pos);
|
| 392 |
|
|
chkstk();
|
| 393 |
|
|
iput (inode);
|
| 394 |
|
|
}
|
| 395 |
|
|
}
|
| 396 |
|
|
}
|
| 397 |
|
|
}
|
| 398 |
|
|
}else{
|
| 399 |
|
|
/* sticky bit set on new_dir */
|
| 400 |
|
|
PRINTK(("sticky set on new "));
|
| 401 |
|
|
ret = -EPERM;
|
| 402 |
|
|
}
|
| 403 |
|
|
}else{
|
| 404 |
|
|
/* sticky bit set on old_dir */
|
| 405 |
|
|
PRINTK(("sticky set on old "));
|
| 406 |
|
|
ret = -EPERM;
|
| 407 |
|
|
}
|
| 408 |
|
|
}
|
| 409 |
|
|
umsdos_unlockcreate(old_dir);
|
| 410 |
|
|
umsdos_unlockcreate(new_dir);
|
| 411 |
|
|
}
|
| 412 |
|
|
iput (old_dir);
|
| 413 |
|
|
iput (new_dir);
|
| 414 |
|
|
PRINTK (("\n"));
|
| 415 |
|
|
return ret;
|
| 416 |
|
|
}
|
| 417 |
|
|
/*
|
| 418 |
|
|
Setup un Symbolic link or a (pseudo) hard link
|
| 419 |
|
|
Return a negative error code or 0 if ok.
|
| 420 |
|
|
*/
|
| 421 |
|
|
static int umsdos_symlink_x(
|
| 422 |
|
|
struct inode * dir,
|
| 423 |
|
|
const char * name,
|
| 424 |
|
|
int len,
|
| 425 |
|
|
const char * symname, /* name will point to this path */
|
| 426 |
|
|
int mode,
|
| 427 |
|
|
char flags)
|
| 428 |
|
|
{
|
| 429 |
|
|
/* #Specification: symbolic links / strategy
|
| 430 |
|
|
A symbolic link is simply a file which hold a path. It is
|
| 431 |
|
|
implemented as a normal MSDOS file (not very space efficient :-()
|
| 432 |
|
|
|
| 433 |
|
|
I see 2 different way to do it. One is to place the link data
|
| 434 |
|
|
in unused entry of the EMD file. The other is to have a separate
|
| 435 |
|
|
file dedicated to hold all symbolic links data.
|
| 436 |
|
|
|
| 437 |
|
|
Let's go for simplicity...
|
| 438 |
|
|
*/
|
| 439 |
|
|
struct inode *inode;
|
| 440 |
|
|
int ret;
|
| 441 |
|
|
dir->i_count++; /* We keep the inode in case we need it */
|
| 442 |
|
|
/* later */
|
| 443 |
|
|
ret = umsdos_create_any (dir,name,len,mode,0,flags,&inode);
|
| 444 |
|
|
PRINTK (("umsdos_symlink ret %d ",ret));
|
| 445 |
|
|
if (ret == 0){
|
| 446 |
|
|
int len = strlen(symname);
|
| 447 |
|
|
struct file filp;
|
| 448 |
|
|
filp.f_pos = 0;
|
| 449 |
|
|
/* Make the inode acceptable to MSDOS */
|
| 450 |
|
|
ret = umsdos_file_write_kmem (inode,&filp,symname,len);
|
| 451 |
|
|
iput (inode);
|
| 452 |
|
|
if (ret >= 0){
|
| 453 |
|
|
if (ret != len){
|
| 454 |
|
|
ret = -EIO;
|
| 455 |
|
|
printk ("UMSDOS: "
|
| 456 |
|
|
"Can't write symbolic link data\n");
|
| 457 |
|
|
}else{
|
| 458 |
|
|
ret = 0;
|
| 459 |
|
|
}
|
| 460 |
|
|
}
|
| 461 |
|
|
if (ret != 0){
|
| 462 |
|
|
UMSDOS_unlink (dir,name,len);
|
| 463 |
|
|
dir = NULL;
|
| 464 |
|
|
}
|
| 465 |
|
|
}
|
| 466 |
|
|
iput (dir);
|
| 467 |
|
|
PRINTK (("\n"));
|
| 468 |
|
|
return ret;
|
| 469 |
|
|
}
|
| 470 |
|
|
/*
|
| 471 |
|
|
Setup un Symbolic link.
|
| 472 |
|
|
Return a negative error code or 0 if ok.
|
| 473 |
|
|
*/
|
| 474 |
|
|
int UMSDOS_symlink(
|
| 475 |
|
|
struct inode * dir,
|
| 476 |
|
|
const char * name,
|
| 477 |
|
|
int len,
|
| 478 |
|
|
const char * symname) /* name will point to this path */
|
| 479 |
|
|
{
|
| 480 |
|
|
return umsdos_symlink_x (dir,name,len,symname,S_IFLNK|0777,0);
|
| 481 |
|
|
}
|
| 482 |
|
|
/*
|
| 483 |
|
|
Add a link to an inode in a directory
|
| 484 |
|
|
*/
|
| 485 |
|
|
int UMSDOS_link (
|
| 486 |
|
|
struct inode * oldinode,
|
| 487 |
|
|
struct inode * dir,
|
| 488 |
|
|
const char * name,
|
| 489 |
|
|
int len)
|
| 490 |
|
|
{
|
| 491 |
|
|
/* #Specification: hard link / strategy
|
| 492 |
|
|
Well ... hard link are difficult to implement on top of an
|
| 493 |
|
|
MsDOS fat file system. Unlike UNIX file systems, there are no
|
| 494 |
|
|
inode. A directory entry hold the functionality of the inode
|
| 495 |
|
|
and the entry.
|
| 496 |
|
|
|
| 497 |
|
|
We will used the same strategy as a normal Unix file system
|
| 498 |
|
|
(with inode) except we will do it symbolically (using paths).
|
| 499 |
|
|
|
| 500 |
|
|
Because anything can happen during a DOS session (defragment,
|
| 501 |
|
|
directory sorting, etc...), we can't rely on MsDOS pseudo
|
| 502 |
|
|
inode number to record the link. For this reason, the link
|
| 503 |
|
|
will be done using hidden symbolic links. The following
|
| 504 |
|
|
scenario illustrate how it work.
|
| 505 |
|
|
|
| 506 |
|
|
Given a file /foo/file
|
| 507 |
|
|
|
| 508 |
|
|
#
|
| 509 |
|
|
ln /foo/file /tmp/file2
|
| 510 |
|
|
|
| 511 |
|
|
become internally
|
| 512 |
|
|
|
| 513 |
|
|
mv /foo/file /foo/-LINK1
|
| 514 |
|
|
ln -s /foo/-LINK1 /foo/file
|
| 515 |
|
|
ln -s /foo/-LINK1 /tmp/file2
|
| 516 |
|
|
#
|
| 517 |
|
|
|
| 518 |
|
|
Using this strategy, we can operate on /foo/file or /foo/file2.
|
| 519 |
|
|
We can remove one and keep the other, like a normal Unix hard link.
|
| 520 |
|
|
We can rename /foo/file or /tmp/file2 independently.
|
| 521 |
|
|
|
| 522 |
|
|
The entry -LINK1 will be hidden. It will hold a link count.
|
| 523 |
|
|
When all link are erased, the hidden file is erased too.
|
| 524 |
|
|
*/
|
| 525 |
|
|
/* #Specification: weakness / hard link
|
| 526 |
|
|
The strategy for hard link introduces a side effect that
|
| 527 |
|
|
may or may not be acceptable. Here is the sequence
|
| 528 |
|
|
|
| 529 |
|
|
#
|
| 530 |
|
|
mkdir subdir1
|
| 531 |
|
|
touch subdir1/file
|
| 532 |
|
|
mkdir subdir2
|
| 533 |
|
|
ln subdir1/file subdir2/file
|
| 534 |
|
|
rm subdir1/file
|
| 535 |
|
|
rmdir subdir1
|
| 536 |
|
|
rmdir: subdir1: Directory not empty
|
| 537 |
|
|
#
|
| 538 |
|
|
|
| 539 |
|
|
This happen because there is an invisible file (--link) in
|
| 540 |
|
|
subdir1 which is referenced by subdir2/file.
|
| 541 |
|
|
|
| 542 |
|
|
Any idea ?
|
| 543 |
|
|
*/
|
| 544 |
|
|
/* #Specification: weakness / hard link / rename directory
|
| 545 |
|
|
Another weakness of hard link come from the fact that
|
| 546 |
|
|
it is based on hidden symbolic links. Here is an example.
|
| 547 |
|
|
|
| 548 |
|
|
#
|
| 549 |
|
|
mkdir /subdir1
|
| 550 |
|
|
touch /subdir1/file
|
| 551 |
|
|
mkdir /subdir2
|
| 552 |
|
|
ln /subdir1/file subdir2/file
|
| 553 |
|
|
mv /subdir1 subdir3
|
| 554 |
|
|
ls -l /subdir2/file
|
| 555 |
|
|
#
|
| 556 |
|
|
|
| 557 |
|
|
Since /subdir2/file is a hidden symbolic link
|
| 558 |
|
|
to /subdir1/..hlinkNNN, accessing it will fail since
|
| 559 |
|
|
/subdir1 does not exist anymore (has been renamed).
|
| 560 |
|
|
*/
|
| 561 |
|
|
int ret = 0;
|
| 562 |
|
|
if (S_ISDIR(oldinode->i_mode)){
|
| 563 |
|
|
/* #Specification: hard link / directory
|
| 564 |
|
|
A hard link can't be made on a directory. EPERM is returned
|
| 565 |
|
|
in this case.
|
| 566 |
|
|
*/
|
| 567 |
|
|
ret = -EPERM;
|
| 568 |
|
|
}else if ((ret = umsdos_nevercreat(dir,name,len,-EPERM))==0){
|
| 569 |
|
|
struct inode *olddir;
|
| 570 |
|
|
ret = umsdos_get_dirowner(oldinode,&olddir);
|
| 571 |
|
|
PRINTK (("umsdos_link dir_owner = %d -> %p [%ld] "
|
| 572 |
|
|
,oldinode->u.umsdos_i.i_dir_owner,olddir,olddir->i_count));
|
| 573 |
|
|
if (ret == 0){
|
| 574 |
|
|
struct umsdos_dirent entry;
|
| 575 |
|
|
umsdos_lockcreate2(dir,olddir);
|
| 576 |
|
|
ret = umsdos_inode2entry (olddir,oldinode,&entry);
|
| 577 |
|
|
if (ret == 0){
|
| 578 |
|
|
PRINTK (("umsdos_link :%s: ino %d flags %d "
|
| 579 |
|
|
,entry.name
|
| 580 |
|
|
,oldinode->i_ino,entry.flags));
|
| 581 |
|
|
if (!(entry.flags & UMSDOS_HIDDEN)){
|
| 582 |
|
|
/* #Specification: hard link / first hard link
|
| 583 |
|
|
The first time a hard link is done on a file, this
|
| 584 |
|
|
file must be renamed and hidden. Then an internal
|
| 585 |
|
|
symbolic link must be done on the hidden file.
|
| 586 |
|
|
|
| 587 |
|
|
The second link is done after on this hidden file.
|
| 588 |
|
|
|
| 589 |
|
|
It is expected that the Linux MSDOS file system
|
| 590 |
|
|
keeps the same pseudo inode when a rename operation
|
| 591 |
|
|
is done on a file in the same directory.
|
| 592 |
|
|
*/
|
| 593 |
|
|
struct umsdos_info info;
|
| 594 |
|
|
ret = umsdos_newhidden (olddir,&info);
|
| 595 |
|
|
if (ret == 0){
|
| 596 |
|
|
olddir->i_count+=2;
|
| 597 |
|
|
PRINTK (("olddir[%ld] ",olddir->i_count));
|
| 598 |
|
|
ret = umsdos_rename_f (olddir,entry.name
|
| 599 |
|
|
,entry.name_len
|
| 600 |
|
|
,olddir,info.entry.name,info.entry.name_len
|
| 601 |
|
|
,UMSDOS_HIDDEN);
|
| 602 |
|
|
if (ret == 0){
|
| 603 |
|
|
char *path = (char*)kmalloc(PATH_MAX,GFP_KERNEL);
|
| 604 |
|
|
if (path == NULL){
|
| 605 |
|
|
ret = -ENOMEM;
|
| 606 |
|
|
}else{
|
| 607 |
|
|
PRINTK (("olddir[%ld] ",olddir->i_count));
|
| 608 |
|
|
ret = umsdos_locate_path (oldinode,path);
|
| 609 |
|
|
PRINTK (("olddir[%ld] ",olddir->i_count));
|
| 610 |
|
|
if (ret == 0){
|
| 611 |
|
|
olddir->i_count++;
|
| 612 |
|
|
ret = umsdos_symlink_x (olddir
|
| 613 |
|
|
,entry.name
|
| 614 |
|
|
,entry.name_len,path
|
| 615 |
|
|
,S_IFREG|0777,UMSDOS_HLINK);
|
| 616 |
|
|
if (ret == 0){
|
| 617 |
|
|
dir->i_count++;
|
| 618 |
|
|
ret = umsdos_symlink_x (dir,name,len
|
| 619 |
|
|
,path
|
| 620 |
|
|
,S_IFREG|0777,UMSDOS_HLINK);
|
| 621 |
|
|
}
|
| 622 |
|
|
}
|
| 623 |
|
|
kfree (path);
|
| 624 |
|
|
}
|
| 625 |
|
|
}
|
| 626 |
|
|
}
|
| 627 |
|
|
}else{
|
| 628 |
|
|
char *path = (char*)kmalloc(PATH_MAX,GFP_KERNEL);
|
| 629 |
|
|
if (path == NULL){
|
| 630 |
|
|
ret = -ENOMEM;
|
| 631 |
|
|
}else{
|
| 632 |
|
|
ret = umsdos_locate_path (oldinode,path);
|
| 633 |
|
|
if (ret == 0){
|
| 634 |
|
|
dir->i_count++;
|
| 635 |
|
|
ret = umsdos_symlink_x (dir,name,len,path
|
| 636 |
|
|
,S_IFREG|0777,UMSDOS_HLINK);
|
| 637 |
|
|
}
|
| 638 |
|
|
kfree (path);
|
| 639 |
|
|
}
|
| 640 |
|
|
}
|
| 641 |
|
|
}
|
| 642 |
|
|
umsdos_unlockcreate(olddir);
|
| 643 |
|
|
umsdos_unlockcreate(dir);
|
| 644 |
|
|
}
|
| 645 |
|
|
iput (olddir);
|
| 646 |
|
|
}
|
| 647 |
|
|
if (ret == 0){
|
| 648 |
|
|
struct iattr newattrs;
|
| 649 |
|
|
oldinode->i_nlink++;
|
| 650 |
|
|
newattrs.ia_valid = 0;
|
| 651 |
|
|
ret = UMSDOS_notify_change(oldinode, &newattrs);
|
| 652 |
|
|
}
|
| 653 |
|
|
iput (oldinode);
|
| 654 |
|
|
iput (dir);
|
| 655 |
|
|
PRINTK (("umsdos_link %d\n",ret));
|
| 656 |
|
|
return ret;
|
| 657 |
|
|
}
|
| 658 |
|
|
/*
|
| 659 |
|
|
Add a new file into the alternate directory.
|
| 660 |
|
|
The file is added to the real MSDOS directory. If successful, it
|
| 661 |
|
|
is then added to the EDM file.
|
| 662 |
|
|
|
| 663 |
|
|
Return the status of the operation. 0 mean success.
|
| 664 |
|
|
*/
|
| 665 |
|
|
int UMSDOS_create (
|
| 666 |
|
|
struct inode *dir,
|
| 667 |
|
|
const char *name, /* Name of the file to add */
|
| 668 |
|
|
int len, /* Length of the name */
|
| 669 |
|
|
int mode, /* Permission bit + file type ??? */
|
| 670 |
|
|
struct inode **result) /* Will hold the inode of the newly created */
|
| 671 |
|
|
/* file */
|
| 672 |
|
|
{
|
| 673 |
|
|
return umsdos_create_any (dir,name,len,mode,0,0,result);
|
| 674 |
|
|
}
|
| 675 |
|
|
/*
|
| 676 |
|
|
Add a sub-directory in a directory
|
| 677 |
|
|
*/
|
| 678 |
|
|
int UMSDOS_mkdir(
|
| 679 |
|
|
struct inode * dir,
|
| 680 |
|
|
const char * name,
|
| 681 |
|
|
int len,
|
| 682 |
|
|
int mode)
|
| 683 |
|
|
{
|
| 684 |
|
|
int ret = umsdos_nevercreat(dir,name,len,-EEXIST);
|
| 685 |
|
|
if (ret == 0){
|
| 686 |
|
|
struct umsdos_info info;
|
| 687 |
|
|
ret = umsdos_parse (name,len,&info);
|
| 688 |
|
|
PRINTK (("umsdos_mkdir %d\n",ret));
|
| 689 |
|
|
if (ret == 0){
|
| 690 |
|
|
info.entry.mode = mode | S_IFDIR;
|
| 691 |
|
|
info.entry.rdev = 0;
|
| 692 |
|
|
info.entry.uid = current->fsuid;
|
| 693 |
|
|
info.entry.gid = (dir->i_mode & S_ISGID)
|
| 694 |
|
|
? dir->i_gid : current->fsgid;
|
| 695 |
|
|
info.entry.ctime = info.entry.atime = info.entry.mtime
|
| 696 |
|
|
= CURRENT_TIME;
|
| 697 |
|
|
info.entry.flags = 0;
|
| 698 |
|
|
umsdos_lockcreate(dir);
|
| 699 |
|
|
info.entry.nlink = 1;
|
| 700 |
|
|
ret = umsdos_newentry (dir,&info);
|
| 701 |
|
|
PRINTK (("newentry %d ",ret));
|
| 702 |
|
|
if (ret == 0){
|
| 703 |
|
|
dir->i_count++;
|
| 704 |
|
|
ret = msdos_mkdir (dir,info.fake.fname,info.fake.len,mode);
|
| 705 |
|
|
if (ret != 0){
|
| 706 |
|
|
umsdos_delentry (dir,&info,1);
|
| 707 |
|
|
/* #Specification: mkdir / Directory already exist in DOS
|
| 708 |
|
|
We do the same thing as for file creation.
|
| 709 |
|
|
For all user it is an error.
|
| 710 |
|
|
*/
|
| 711 |
|
|
}else{
|
| 712 |
|
|
/* #Specification: mkdir / umsdos directory / create EMD
|
| 713 |
|
|
When we created a new sub-directory in a UMSDOS
|
| 714 |
|
|
directory (one with full UMSDOS semantic), we
|
| 715 |
|
|
create immediately an EMD file in the new
|
| 716 |
|
|
sub-directory so it inherit UMSDOS semantic.
|
| 717 |
|
|
*/
|
| 718 |
|
|
struct inode *subdir;
|
| 719 |
|
|
ret = umsdos_real_lookup (dir,info.fake.fname
|
| 720 |
|
|
,info.fake.len,&subdir);
|
| 721 |
|
|
if (ret == 0){
|
| 722 |
|
|
struct inode *result;
|
| 723 |
|
|
ret = msdos_create (subdir,UMSDOS_EMD_FILE
|
| 724 |
|
|
,UMSDOS_EMD_NAMELEN,S_IFREG|0777,&result);
|
| 725 |
|
|
subdir = NULL;
|
| 726 |
|
|
iput (result);
|
| 727 |
|
|
}
|
| 728 |
|
|
if (ret < 0){
|
| 729 |
|
|
printk ("UMSDOS: Can't create empty --linux-.---\n");
|
| 730 |
|
|
}
|
| 731 |
|
|
iput (subdir);
|
| 732 |
|
|
}
|
| 733 |
|
|
}
|
| 734 |
|
|
umsdos_unlockcreate(dir);
|
| 735 |
|
|
}
|
| 736 |
|
|
}
|
| 737 |
|
|
PRINTK (("umsdos_mkdir %d\n",ret));
|
| 738 |
|
|
iput (dir);
|
| 739 |
|
|
return ret;
|
| 740 |
|
|
}
|
| 741 |
|
|
/*
|
| 742 |
|
|
Add a new device special file into a directory.
|
| 743 |
|
|
*/
|
| 744 |
|
|
int UMSDOS_mknod(
|
| 745 |
|
|
struct inode * dir,
|
| 746 |
|
|
const char * name,
|
| 747 |
|
|
int len,
|
| 748 |
|
|
int mode,
|
| 749 |
|
|
int rdev)
|
| 750 |
|
|
{
|
| 751 |
|
|
/* #Specification: Special files / strategy
|
| 752 |
|
|
Device special file, pipes, etc ... are created like normal
|
| 753 |
|
|
file in the msdos file system. Of course they remain empty.
|
| 754 |
|
|
|
| 755 |
|
|
One strategy was to create those files only in the EMD file
|
| 756 |
|
|
since they were not important for MSDOS. The problem with
|
| 757 |
|
|
that, is that there were not getting inode number allocated.
|
| 758 |
|
|
The MSDOS filesystems is playing a nice game to fake inode
|
| 759 |
|
|
number, so why not use it.
|
| 760 |
|
|
|
| 761 |
|
|
The absence of inode number compatible with those allocated
|
| 762 |
|
|
for ordinary files was causing major trouble with hard link
|
| 763 |
|
|
in particular and other parts of the kernel I guess.
|
| 764 |
|
|
*/
|
| 765 |
|
|
struct inode *inode;
|
| 766 |
|
|
int ret = umsdos_create_any (dir,name,len,mode,rdev,0,&inode);
|
| 767 |
|
|
iput (inode);
|
| 768 |
|
|
return ret;
|
| 769 |
|
|
}
|
| 770 |
|
|
|
| 771 |
|
|
/*
|
| 772 |
|
|
Remove a sub-directory.
|
| 773 |
|
|
*/
|
| 774 |
|
|
int UMSDOS_rmdir(
|
| 775 |
|
|
struct inode * dir,
|
| 776 |
|
|
const char * name,
|
| 777 |
|
|
int len)
|
| 778 |
|
|
{
|
| 779 |
|
|
/* #Specification: style / iput strategy
|
| 780 |
|
|
In the UMSDOS project, I am trying to apply a single
|
| 781 |
|
|
programming style regarding inode management. Many
|
| 782 |
|
|
entry point are receiving an inode to act on, and must
|
| 783 |
|
|
do an iput() as soon as they are finished with
|
| 784 |
|
|
the inode.
|
| 785 |
|
|
|
| 786 |
|
|
For simple case, there is no problem. When you introduce
|
| 787 |
|
|
error checking, you end up with many iput placed around the
|
| 788 |
|
|
code.
|
| 789 |
|
|
|
| 790 |
|
|
The coding style I use all around is one where I am trying
|
| 791 |
|
|
to provide independent flow logic (I don't know how to
|
| 792 |
|
|
name this). With this style, code is easier to understand
|
| 793 |
|
|
but you rapidly get iput() all around. Here is an exemple
|
| 794 |
|
|
of what I am trying to avoid.
|
| 795 |
|
|
|
| 796 |
|
|
#
|
| 797 |
|
|
if (a){
|
| 798 |
|
|
...
|
| 799 |
|
|
if(b){
|
| 800 |
|
|
...
|
| 801 |
|
|
}
|
| 802 |
|
|
...
|
| 803 |
|
|
if (c){
|
| 804 |
|
|
// Complex state. Was b true ?
|
| 805 |
|
|
...
|
| 806 |
|
|
}
|
| 807 |
|
|
...
|
| 808 |
|
|
}
|
| 809 |
|
|
// Weird state
|
| 810 |
|
|
if (d){
|
| 811 |
|
|
// ...
|
| 812 |
|
|
}
|
| 813 |
|
|
// Was iput finally done ?
|
| 814 |
|
|
return status;
|
| 815 |
|
|
#
|
| 816 |
|
|
|
| 817 |
|
|
Here is the style I am using. Still sometime I do the
|
| 818 |
|
|
first when things are very simple (or very complicated :-( )
|
| 819 |
|
|
|
| 820 |
|
|
#
|
| 821 |
|
|
if (a){
|
| 822 |
|
|
if (b){
|
| 823 |
|
|
...
|
| 824 |
|
|
}else if (c){
|
| 825 |
|
|
// A single state gets here
|
| 826 |
|
|
}
|
| 827 |
|
|
}else if (d){
|
| 828 |
|
|
...
|
| 829 |
|
|
}
|
| 830 |
|
|
return status;
|
| 831 |
|
|
#
|
| 832 |
|
|
|
| 833 |
|
|
Again, while this help clarifying the code, I often get a lot
|
| 834 |
|
|
of iput(), unlike the first style, where I can place few
|
| 835 |
|
|
"strategic" iput(). "strategic" also mean, more difficult
|
| 836 |
|
|
to place.
|
| 837 |
|
|
|
| 838 |
|
|
So here is the style I will be using from now on in this project.
|
| 839 |
|
|
There is always an iput() at the end of a function (which has
|
| 840 |
|
|
to do an iput()). One iput by inode. There is also one iput()
|
| 841 |
|
|
at the places where a successful operation is achieved. This
|
| 842 |
|
|
iput() is often done by a sub-function (often from the msdos
|
| 843 |
|
|
file system). So I get one too many iput() ? At the place
|
| 844 |
|
|
where an iput() is done, the inode is simply nulled, disabling
|
| 845 |
|
|
the last one.
|
| 846 |
|
|
|
| 847 |
|
|
#
|
| 848 |
|
|
if (a){
|
| 849 |
|
|
if (b){
|
| 850 |
|
|
...
|
| 851 |
|
|
}else if (c){
|
| 852 |
|
|
msdos_rmdir(dir,...);
|
| 853 |
|
|
dir = NULL;
|
| 854 |
|
|
}
|
| 855 |
|
|
}else if (d){
|
| 856 |
|
|
...
|
| 857 |
|
|
}
|
| 858 |
|
|
iput (dir);
|
| 859 |
|
|
return status;
|
| 860 |
|
|
#
|
| 861 |
|
|
|
| 862 |
|
|
Note that the umsdos_lockcreate() and umsdos_unlockcreate() function
|
| 863 |
|
|
pair goes against this practice of "forgetting" the inode as soon
|
| 864 |
|
|
as possible.
|
| 865 |
|
|
*/
|
| 866 |
|
|
int ret = umsdos_nevercreat(dir,name,len,-EPERM);
|
| 867 |
|
|
if (ret == 0){
|
| 868 |
|
|
struct inode *sdir;
|
| 869 |
|
|
dir->i_count++;
|
| 870 |
|
|
ret = UMSDOS_lookup (dir,name,len,&sdir);
|
| 871 |
|
|
PRINTK (("rmdir lookup %d ",ret));
|
| 872 |
|
|
if (ret == 0){
|
| 873 |
|
|
int empty;
|
| 874 |
|
|
umsdos_lockcreate(dir);
|
| 875 |
|
|
if (sdir->i_count > 1){
|
| 876 |
|
|
ret = -EBUSY;
|
| 877 |
|
|
}else if ((empty = umsdos_isempty (sdir)) != 0){
|
| 878 |
|
|
PRINTK (("isempty %d i_count %ld ",empty,sdir->i_count));
|
| 879 |
|
|
/* check sticky bit */
|
| 880 |
|
|
if ( !(dir->i_mode & S_ISVTX) || fsuser() ||
|
| 881 |
|
|
current->fsuid == sdir->i_uid ||
|
| 882 |
|
|
current->fsuid == dir->i_uid ) {
|
| 883 |
|
|
if (empty == 1){
|
| 884 |
|
|
/* We have to removed the EMD file */
|
| 885 |
|
|
ret = msdos_unlink(sdir,UMSDOS_EMD_FILE
|
| 886 |
|
|
,UMSDOS_EMD_NAMELEN);
|
| 887 |
|
|
sdir = NULL;
|
| 888 |
|
|
}
|
| 889 |
|
|
/* sdir must be free before msdos_rmdir() */
|
| 890 |
|
|
iput (sdir);
|
| 891 |
|
|
sdir = NULL;
|
| 892 |
|
|
PRINTK (("isempty ret %d nlink %d ",ret,dir->i_nlink));
|
| 893 |
|
|
if (ret == 0){
|
| 894 |
|
|
struct umsdos_info info;
|
| 895 |
|
|
dir->i_count++;
|
| 896 |
|
|
umsdos_parse (name,len,&info);
|
| 897 |
|
|
/* The findentry is there only to complete */
|
| 898 |
|
|
/* the mangling */
|
| 899 |
|
|
umsdos_findentry (dir,&info,2);
|
| 900 |
|
|
ret = msdos_rmdir (dir,info.fake.fname
|
| 901 |
|
|
,info.fake.len);
|
| 902 |
|
|
if (ret == 0){
|
| 903 |
|
|
ret = umsdos_delentry (dir,&info,1);
|
| 904 |
|
|
}
|
| 905 |
|
|
}
|
| 906 |
|
|
}else{
|
| 907 |
|
|
/* sticky bit set and we don't have permission */
|
| 908 |
|
|
PRINTK(("sticky set "));
|
| 909 |
|
|
ret = -EPERM;
|
| 910 |
|
|
}
|
| 911 |
|
|
}else{
|
| 912 |
|
|
/*
|
| 913 |
|
|
The subdirectory is not empty, so leave it there
|
| 914 |
|
|
*/
|
| 915 |
|
|
ret = -ENOTEMPTY;
|
| 916 |
|
|
}
|
| 917 |
|
|
iput(sdir);
|
| 918 |
|
|
umsdos_unlockcreate(dir);
|
| 919 |
|
|
}
|
| 920 |
|
|
}
|
| 921 |
|
|
iput (dir);
|
| 922 |
|
|
PRINTK (("umsdos_rmdir %d\n",ret));
|
| 923 |
|
|
return ret;
|
| 924 |
|
|
}
|
| 925 |
|
|
/*
|
| 926 |
|
|
Remove a file from the directory.
|
| 927 |
|
|
*/
|
| 928 |
|
|
int UMSDOS_unlink (
|
| 929 |
|
|
struct inode * dir,
|
| 930 |
|
|
const char * name,
|
| 931 |
|
|
int len)
|
| 932 |
|
|
{
|
| 933 |
|
|
int ret = umsdos_nevercreat(dir,name,len,-EPERM);
|
| 934 |
|
|
if (ret == 0){
|
| 935 |
|
|
struct umsdos_info info;
|
| 936 |
|
|
ret = umsdos_parse (name,len,&info);
|
| 937 |
|
|
if (ret == 0){
|
| 938 |
|
|
umsdos_lockcreate(dir);
|
| 939 |
|
|
ret = umsdos_findentry(dir,&info,1);
|
| 940 |
|
|
if (ret == 0){
|
| 941 |
|
|
PRINTK (("UMSDOS_unlink %s ",info.fake.fname));
|
| 942 |
|
|
/* check sticky bit */
|
| 943 |
|
|
if ( !(dir->i_mode & S_ISVTX) || fsuser() ||
|
| 944 |
|
|
current->fsuid == info.entry.uid ||
|
| 945 |
|
|
current->fsuid == dir->i_uid ) {
|
| 946 |
|
|
if (info.entry.flags & UMSDOS_HLINK){
|
| 947 |
|
|
/* #Specification: hard link / deleting a link
|
| 948 |
|
|
When we deletes a file, and this file is a link
|
| 949 |
|
|
we must subtract 1 to the nlink field of the
|
| 950 |
|
|
hidden link.
|
| 951 |
|
|
|
| 952 |
|
|
If the count goes to 0, we delete this hidden
|
| 953 |
|
|
link too.
|
| 954 |
|
|
*/
|
| 955 |
|
|
/*
|
| 956 |
|
|
First, get the inode of the hidden link
|
| 957 |
|
|
using the standard lookup function.
|
| 958 |
|
|
*/
|
| 959 |
|
|
struct inode *inode;
|
| 960 |
|
|
dir->i_count++;
|
| 961 |
|
|
ret = UMSDOS_lookup (dir,name,len,&inode);
|
| 962 |
|
|
if (ret == 0){
|
| 963 |
|
|
PRINTK (("unlink nlink = %d ",inode->i_nlink));
|
| 964 |
|
|
inode->i_nlink--;
|
| 965 |
|
|
if (inode->i_nlink == 0){
|
| 966 |
|
|
struct inode *hdir = iget(inode->i_sb
|
| 967 |
|
|
,inode->u.umsdos_i.i_dir_owner);
|
| 968 |
|
|
struct umsdos_dirent entry;
|
| 969 |
|
|
ret = umsdos_inode2entry (hdir,inode,&entry);
|
| 970 |
|
|
if (ret == 0){
|
| 971 |
|
|
ret = UMSDOS_unlink (hdir,entry.name
|
| 972 |
|
|
,entry.name_len);
|
| 973 |
|
|
}else{
|
| 974 |
|
|
iput (hdir);
|
| 975 |
|
|
}
|
| 976 |
|
|
}else{
|
| 977 |
|
|
struct iattr newattrs;
|
| 978 |
|
|
newattrs.ia_valid = 0;
|
| 979 |
|
|
ret = UMSDOS_notify_change (inode, &newattrs);
|
| 980 |
|
|
}
|
| 981 |
|
|
iput (inode);
|
| 982 |
|
|
}
|
| 983 |
|
|
}
|
| 984 |
|
|
if (ret == 0){
|
| 985 |
|
|
ret = umsdos_delentry (dir,&info,0);
|
| 986 |
|
|
if (ret == 0){
|
| 987 |
|
|
PRINTK (("Avant msdos_unlink %s ",info.fake.fname));
|
| 988 |
|
|
dir->i_count++;
|
| 989 |
|
|
ret = msdos_unlink_umsdos (dir,info.fake.fname
|
| 990 |
|
|
,info.fake.len);
|
| 991 |
|
|
PRINTK (("msdos_unlink %s %o ret %d ",info.fake.fname
|
| 992 |
|
|
,info.entry.mode,ret));
|
| 993 |
|
|
}
|
| 994 |
|
|
}
|
| 995 |
|
|
}else{
|
| 996 |
|
|
/* sticky bit set and we've not got permission */
|
| 997 |
|
|
PRINTK(("sticky set "));
|
| 998 |
|
|
ret = -EPERM;
|
| 999 |
|
|
}
|
| 1000 |
|
|
}
|
| 1001 |
|
|
umsdos_unlockcreate(dir);
|
| 1002 |
|
|
}
|
| 1003 |
|
|
}
|
| 1004 |
|
|
iput (dir);
|
| 1005 |
|
|
PRINTK (("umsdos_unlink %d\n",ret));
|
| 1006 |
|
|
return ret;
|
| 1007 |
|
|
}
|
| 1008 |
|
|
|
| 1009 |
|
|
/*
|
| 1010 |
|
|
Rename a file (move) in the file system.
|
| 1011 |
|
|
*/
|
| 1012 |
|
|
int UMSDOS_rename(
|
| 1013 |
|
|
struct inode * old_dir,
|
| 1014 |
|
|
const char * old_name,
|
| 1015 |
|
|
int old_len,
|
| 1016 |
|
|
struct inode * new_dir,
|
| 1017 |
|
|
const char * new_name,
|
| 1018 |
|
|
int new_len,
|
| 1019 |
|
|
int must_be_dir)
|
| 1020 |
|
|
{
|
| 1021 |
|
|
/* #Specification: weakness / rename
|
| 1022 |
|
|
There is a case where UMSDOS rename has a different behavior
|
| 1023 |
|
|
than normal UNIX file system. Renaming an open file across
|
| 1024 |
|
|
directory boundary does not work. Renaming an open file within
|
| 1025 |
|
|
a directory does work however.
|
| 1026 |
|
|
|
| 1027 |
|
|
The problem (not sure) is in the linux VFS msdos driver.
|
| 1028 |
|
|
I believe this is not a bug but a design feature, because
|
| 1029 |
|
|
an inode number represent some sort of directory address
|
| 1030 |
|
|
in the MSDOS directory structure. So moving the file into
|
| 1031 |
|
|
another directory does not preserve the inode number.
|
| 1032 |
|
|
*/
|
| 1033 |
|
|
int ret = umsdos_nevercreat(new_dir,new_name,new_len,-EEXIST);
|
| 1034 |
|
|
if (ret == 0){
|
| 1035 |
|
|
/* umsdos_rename_f eat the inode and we may need those later */
|
| 1036 |
|
|
old_dir->i_count++;
|
| 1037 |
|
|
new_dir->i_count++;
|
| 1038 |
|
|
ret = umsdos_rename_f (old_dir,old_name,old_len,new_dir,new_name
|
| 1039 |
|
|
,new_len,0);
|
| 1040 |
|
|
if (ret == -EEXIST){
|
| 1041 |
|
|
/* #Specification: rename / new name exist
|
| 1042 |
|
|
If the destination name already exist, it will
|
| 1043 |
|
|
silently be removed. EXT2 does it this way
|
| 1044 |
|
|
and this is the spec of SUNOS. So does UMSDOS.
|
| 1045 |
|
|
|
| 1046 |
|
|
If the destination is an empty directory it will
|
| 1047 |
|
|
also be removed.
|
| 1048 |
|
|
*/
|
| 1049 |
|
|
/* #Specification: rename / new name exist / possible flaw
|
| 1050 |
|
|
The code to handle the deletion of the target (file
|
| 1051 |
|
|
and directory) use to be in umsdos_rename_f, surrounded
|
| 1052 |
|
|
by proper directory locking. This was insuring that only
|
| 1053 |
|
|
one process could achieve a rename (modification) operation
|
| 1054 |
|
|
in the source and destination directory. This was also
|
| 1055 |
|
|
insuring the operation was "atomic".
|
| 1056 |
|
|
|
| 1057 |
|
|
This has been changed because this was creating a kernel
|
| 1058 |
|
|
stack overflow (stack is only 4k in the kernel). To avoid
|
| 1059 |
|
|
the code doing the deletion of the target (if exist) has
|
| 1060 |
|
|
been moved to a upper layer. umsdos_rename_f is tried
|
| 1061 |
|
|
once and if it fails with EEXIST, the target is removed
|
| 1062 |
|
|
and umsdos_rename_f is done again.
|
| 1063 |
|
|
|
| 1064 |
|
|
This makes the code cleaner and (not sure) solve a
|
| 1065 |
|
|
deadlock problem one tester was experiencing.
|
| 1066 |
|
|
|
| 1067 |
|
|
The point is to mention that possibly, the semantic of
|
| 1068 |
|
|
"rename" may be wrong. Anyone dare to check that :-)
|
| 1069 |
|
|
Be aware that IF it is wrong, to produce the problem you
|
| 1070 |
|
|
will need two process trying to rename a file to the
|
| 1071 |
|
|
same target at the same time. Again, I am not sure it
|
| 1072 |
|
|
is a problem at all.
|
| 1073 |
|
|
*/
|
| 1074 |
|
|
/* This is not super efficient but should work */
|
| 1075 |
|
|
new_dir->i_count++;
|
| 1076 |
|
|
ret = UMSDOS_unlink (new_dir,new_name,new_len);
|
| 1077 |
|
|
chkstk();
|
| 1078 |
|
|
PRINTK (("rename unlink ret %d %d -- ",ret,new_len));
|
| 1079 |
|
|
if (ret == -EISDIR){
|
| 1080 |
|
|
new_dir->i_count++;
|
| 1081 |
|
|
ret = UMSDOS_rmdir (new_dir,new_name,new_len);
|
| 1082 |
|
|
chkstk();
|
| 1083 |
|
|
PRINTK (("rename rmdir ret %d -- ",ret));
|
| 1084 |
|
|
}
|
| 1085 |
|
|
if (ret == 0){
|
| 1086 |
|
|
ret = umsdos_rename_f (old_dir,old_name,old_len
|
| 1087 |
|
|
,new_dir,new_name,new_len,0);
|
| 1088 |
|
|
new_dir = old_dir = NULL;
|
| 1089 |
|
|
}
|
| 1090 |
|
|
}
|
| 1091 |
|
|
}
|
| 1092 |
|
|
iput (new_dir);
|
| 1093 |
|
|
iput (old_dir);
|
| 1094 |
|
|
return ret;
|
| 1095 |
|
|
}
|
| 1096 |
|
|
|
