/* Locate the EMD file in a directory and optionally, creates it. Return NULL if error. If ok, dir->u.umsdos_i.emd_inode */ struct inode *umsdos_emd_dir_lookup(struct inode *dir, int creat) { struct inode *ret = NULL; if (dir->u.umsdos_i.i_emd_dir != 0){ ret = iget (dir->i_sb,dir->u.umsdos_i.i_emd_dir); PRINTK (("deja trouve %d %x [%d] " ,dir->u.umsdos_i.i_emd_dir,ret,ret->i_count)); }else{ umsdos_real_lookup (dir,UMSDOS_EMD_FILE,UMSDOS_EMD_NAMELEN,&ret); PRINTK (("emd_dir_lookup ")); if (ret != NULL){ PRINTK (("Find --linux ")); dir->u.umsdos_i.i_emd_dir = ret->i_ino; }else if (creat){ int code; PRINTK (("avant create ")); dir->i_count++; code = msdos_create (dir,UMSDOS_EMD_FILE,UMSDOS_EMD_NAMELEN ,S_IFREG|0777,&ret); PRINTK (("Creat EMD code %d ret %x ",code,ret)); if (ret != NULL){ dir->u.umsdos_i.i_emd_dir = ret->i_ino; }else{ printk ("UMSDOS: Can't create EMD file\n"); } } } if (ret != NULL){ /* Disable UMSDOS_notify_change() for EMD file */ ret->u.umsdos_i.i_emd_owner = 0xffffffff; } return ret; }
/* Lookup into a non promoted directory. If the result is a directory, make sure we find out if it is a promoted one or not (calling umsdos_setup_dir_inode(inode)). */ int umsdos_rlookup_x( struct inode *dir, const char *name, int len, struct inode **result, /* Will hold inode of the file, if successful */ int nopseudo) /* Don't care about pseudo root mode */ /* so locating "linux" will work */ { int ret; if (pseudo_root != NULL && len == 2 && name[0] == '.' && name[1] == '.' && dir == dir->i_sb->s_mounted && dir == pseudo_root->i_sb->s_mounted){ *result = pseudo_root; pseudo_root->i_count++; ret = 0; /* #Specification: pseudo root / DOS/.. In the real root directory (c:\), the directory .. is the pseudo root (c:\linux). */ }else{ ret = umsdos_real_lookup (dir,name,len,result); if (ret == 0){ struct inode *inode = *result; if (inode == pseudo_root && !nopseudo){ /* #Specification: pseudo root / DOS/linux Even in the real root directory (c:\), the directory /linux won't show */ ret = -ENOENT; iput (pseudo_root); *result = NULL; }else if (S_ISDIR(inode->i_mode)){ /* We must place the proper function table */ /* depending if this is a MsDOS directory or an UMSDOS directory */ umsdos_setup_dir_inode(inode); } } } iput (dir); return ret; }
/* Perform special function on a directory */ int UMSDOS_ioctl_dir ( struct inode *dir, struct file *filp, unsigned int cmd, unsigned long data) { int ret = -EPERM; /* #Specification: ioctl / acces Only root (effective id) is allowed to do IOCTL on directory in UMSDOS. EPERM is returned for other user. */ if (current->euid == 0 || cmd == UMSDOS_GETVERSION){ struct umsdos_ioctl *idata = (struct umsdos_ioctl *)data; ret = -EINVAL; /* #Specification: ioctl / prototypes The official prototype for the umsdos ioctl on directory is: int ioctl ( int fd, // File handle of the directory int cmd, // command struct umsdos_ioctl *data) The struct and the commands are defined in linux/umsdos_fs.h. umsdos_progs/umsdosio.c provide an interface in C++ to all these ioctl. umsdos_progs/udosctl is a small utility showing all this. These ioctl generally allow one to work on the EMD or the DOS directory independently. These are essential to implement the synchronise. */ PRINTK (("ioctl %d ",cmd)); if (cmd == UMSDOS_GETVERSION){ /* #Specification: ioctl / UMSDOS_GETVERSION The field version and release of the structure umsdos_ioctl are filled with the version and release number of the fs code in the kernel. This will allow some form of checking. Users won't be able to run incompatible utility such as the synchroniser (umssync). umsdos_progs/umsdosio.c enforce this checking. Return always 0. */ put_fs_byte (UMSDOS_VERSION,&idata->version); put_fs_byte (UMSDOS_RELEASE,&idata->release); ret = 0; }else if (cmd == UMSDOS_READDIR_DOS){ /* #Specification: ioctl / UMSDOS_READDIR_DOS One entry is read from the DOS directory at the current file position. The entry is put as is in the dos_dirent field of struct umsdos_ioctl. Return > 0 if success. */ ret = msdos_readdir(dir,filp,&idata->dos_dirent,1); }else if (cmd == UMSDOS_READDIR_EMD){ /* #Specification: ioctl / UMSDOS_READDIR_EMD One entry is read from the EMD at the current file position. The entry is put as is in the umsdos_dirent field of struct umsdos_ioctl. The corresponding mangled DOS entry name is put in the dos_dirent field. All entries are read including hidden links. Blank entries are skipped. Return > 0 if success. */ struct inode *emd_dir = umsdos_emd_dir_lookup (dir,0); if (emd_dir != NULL){ while (1){ if (filp->f_pos >= emd_dir->i_size){ ret = 0; break; }else{ struct umsdos_dirent entry; off_t f_pos = filp->f_pos; ret = umsdos_emd_dir_readentry (emd_dir,filp,&entry); if (ret < 0){ break; }else if (entry.name_len > 0){ struct umsdos_info info; ret = entry.name_len; umsdos_parse (entry.name,entry.name_len,&info); info.f_pos = f_pos; umsdos_manglename(&info); memcpy_tofs(&idata->umsdos_dirent,&entry ,sizeof(entry)); memcpy_tofs(&idata->dos_dirent.d_name ,info.fake.fname,info.fake.len+1); break; } } } iput (emd_dir); }else{ /* The absence of the EMD is simply seen as an EOF */ ret = 0; } }else if (cmd == UMSDOS_INIT_EMD){ /* #Specification: ioctl / UMSDOS_INIT_EMD The UMSDOS_INIT_EMD command make sure the EMD exist for a directory. If it does not, it is created. Also, it makes sure the directory functions table (struct inode_operations) is set to the UMSDOS semantic. This mean that umssync may be applied to an "opened" msdos directory, and it will change behavior on the fly. Return 0 if success. */ extern struct inode_operations umsdos_rdir_inode_operations; struct inode *emd_dir = umsdos_emd_dir_lookup (dir,1); ret = emd_dir != NULL; iput (emd_dir); dir->i_op = ret ? &umsdos_dir_inode_operations : &umsdos_rdir_inode_operations; }else{ struct umsdos_ioctl data; memcpy_fromfs (&data,idata,sizeof(data)); if (cmd == UMSDOS_CREAT_EMD){ /* #Specification: ioctl / UMSDOS_CREAT_EMD The umsdos_dirent field of the struct umsdos_ioctl is used as is to create a new entry in the EMD of the directory. The DOS directory is not modified. No validation is done (yet). Return 0 if success. */ struct umsdos_info info; /* This makes sure info.entry and info in general is correctly */ /* initialised */ memcpy (&info.entry,&data.umsdos_dirent ,sizeof(data.umsdos_dirent)); umsdos_parse (data.umsdos_dirent.name ,data.umsdos_dirent.name_len,&info); ret = umsdos_newentry (dir,&info); }else if (cmd == UMSDOS_RENAME_DOS){ /* #Specification: ioctl / UMSDOS_RENAME_DOS A file or directory is rename in a DOS directory (not moved across directory). The source name is in the dos_dirent.name field and the destination is in umsdos_dirent.name field. This ioctl allows umssync to rename a mangle file name before syncing it back in the EMD. */ dir->i_count += 2; ret = msdos_rename (dir ,data.dos_dirent.d_name,data.dos_dirent.d_reclen ,dir ,data.umsdos_dirent.name,data.umsdos_dirent.name_len); }else if (cmd == UMSDOS_UNLINK_EMD){ /* #Specification: ioctl / UMSDOS_UNLINK_EMD The umsdos_dirent field of the struct umsdos_ioctl is used as is to remove an entry from the EMD of the directory. No validation is done (yet). The mode field is used to validate S_ISDIR or S_ISREG. Return 0 if success. */ struct umsdos_info info; /* This makes sure info.entry and info in general is correctly */ /* initialised */ memcpy (&info.entry,&data.umsdos_dirent ,sizeof(data.umsdos_dirent)); umsdos_parse (data.umsdos_dirent.name ,data.umsdos_dirent.name_len,&info); ret = umsdos_delentry (dir,&info ,S_ISDIR(data.umsdos_dirent.mode)); }else if (cmd == UMSDOS_UNLINK_DOS){ /* #Specification: ioctl / UMSDOS_UNLINK_DOS The dos_dirent field of the struct umsdos_ioctl is used to execute a msdos_unlink operation. The d_name and d_reclen fields are used. Return 0 if success. */ dir->i_count++; ret = msdos_unlink (dir,data.dos_dirent.d_name ,data.dos_dirent.d_reclen); }else if (cmd == UMSDOS_RMDIR_DOS){ /* #Specification: ioctl / UMSDOS_RMDIR_DOS The dos_dirent field of the struct umsdos_ioctl is used to execute a msdos_unlink operation. The d_name and d_reclen fields are used. Return 0 if success. */ dir->i_count++; ret = msdos_rmdir (dir,data.dos_dirent.d_name ,data.dos_dirent.d_reclen); }else if (cmd == UMSDOS_STAT_DOS){ /* #Specification: ioctl / UMSDOS_STAT_DOS The dos_dirent field of the struct umsdos_ioctl is used to execute a stat operation in the DOS directory. The d_name and d_reclen fields are used. The following field of umsdos_ioctl.stat are filled. st_ino,st_mode,st_size,st_atime,st_mtime,st_ctime, Return 0 if success. */ struct inode *inode; ret = umsdos_real_lookup (dir,data.dos_dirent.d_name ,data.dos_dirent.d_reclen,&inode); if (ret == 0){ data.stat.st_ino = inode->i_ino; data.stat.st_mode = inode->i_mode; data.stat.st_size = inode->i_size; data.stat.st_atime = inode->i_atime; data.stat.st_ctime = inode->i_ctime; data.stat.st_mtime = inode->i_mtime; memcpy_tofs (&idata->stat,&data.stat,sizeof(data.stat)); iput (inode); } }else if (cmd == UMSDOS_DOS_SETUP){ /* #Specification: ioctl / UMSDOS_DOS_SETUP The UMSDOS_DOS_SETUP ioctl allow changing the default permission of the MsDOS file system driver on the fly. The MsDOS driver apply global permission to every file and directory. Normally these permissions are controlled by a mount option. This is not available for root partition, so a special utility (umssetup) is provided to do this, normally in /etc/rc.local. Be aware that this apply ONLY to MsDOS directory (those without EMD --linux-.---). Umsdos directory have independent (standard) permission for each and every file. The field umsdos_dirent provide the information needed. umsdos_dirent.uid and gid sets the owner and group. umsdos_dirent.mode set the permissions flags. */ dir->i_sb->u.msdos_sb.fs_uid = data.umsdos_dirent.uid; dir->i_sb->u.msdos_sb.fs_gid = data.umsdos_dirent.gid; dir->i_sb->u.msdos_sb.fs_umask = data.umsdos_dirent.mode; ret = 0; } } } PRINTK (("ioctl return %d\n",ret)); return ret; }
/* Read the super block of an Extended MS-DOS FS. */ struct super_block *UMSDOS_read_super( struct super_block *s, void *data, int silent) { /* #Specification: mount / options Umsdos run on top of msdos. Currently, it supports no mount option, but happily pass all option received to the msdos driver. I am not sure if all msdos mount option make sense with Umsdos. Here are at least those who are useful. uid= gid= These options affect the operation of umsdos in directories which do not have an EMD file. They behave like normal msdos directory, with all limitation of msdos. */ struct super_block *sb; MOD_INC_USE_COUNT; sb = msdos_read_super(s,data,silent); printk ("UMSDOS Beta 0.6 (compatibility level %d.%d, fast msdos)\n" ,UMSDOS_VERSION,UMSDOS_RELEASE); if (sb != NULL){ MSDOS_SB(sb)->options.dotsOK = 0; /* disable hidden==dotfile */ sb->s_op = &umsdos_sops; PRINTK (("umsdos_read_super %p\n",sb->s_mounted)); umsdos_setup_dir_inode (sb->s_mounted); PRINTK (("End umsdos_read_super\n")); if (s == super_blocks){ /* #Specification: pseudo root / mount When a umsdos fs is mounted, a special handling is done if it is the root partition. We check for the presence of the file /linux/etc/init or /linux/etc/rc or /linux/sbin/init. If one is there, we do a chroot("/linux"). We check both because (see init/main.c) the kernel try to exec init at different place and if it fails it tries /bin/sh /etc/rc. To be consistent with init/main.c, many more test would have to be done to locate init. Any complain ? The chroot is done manually in init/main.c but the info (the inode) is located at mount time and store in a global variable (pseudo_root) which is used at different place in the umsdos driver. There is no need to store this variable elsewhere because it will always be one, not one per mount. This feature allows the installation of a linux system within a DOS system in a subdirectory. A user may install its linux stuff in c:\linux avoiding any clash with existing DOS file and subdirectory. When linux boots, it hides this fact, showing a normal root directory with /etc /bin /tmp ... The word "linux" is hardcoded in /usr/include/linux/umsdos_fs.h in the macro UMSDOS_PSDROOT_NAME. */ struct inode *pseudo; Printk (("Mounting root\n")); if (umsdos_real_lookup (sb->s_mounted,UMSDOS_PSDROOT_NAME ,UMSDOS_PSDROOT_LEN,&pseudo)==0 && S_ISDIR(pseudo->i_mode)){ struct inode *etc = NULL; struct inode *sbin = NULL; int pseudo_ok = 0; Printk (("/%s is there\n",UMSDOS_PSDROOT_NAME)); if (umsdos_real_lookup (pseudo,"etc",3,&etc)==0 && S_ISDIR(etc->i_mode)){ struct inode *init = NULL; struct inode *rc = NULL; Printk (("/%s/etc is there\n",UMSDOS_PSDROOT_NAME)); if ((umsdos_real_lookup (etc,"init",4,&init)==0 && S_ISREG(init->i_mode)) || (umsdos_real_lookup (etc,"rc",2,&rc)==0 && S_ISREG(rc->i_mode))){ pseudo_ok = 1; } iput (init); iput (rc); } if (!pseudo_ok && umsdos_real_lookup (pseudo,"sbin",4,&sbin)==0 && S_ISDIR(sbin->i_mode)){ struct inode *init = NULL; Printk (("/%s/sbin is there\n",UMSDOS_PSDROOT_NAME)); if (umsdos_real_lookup (sbin,"init",4,&init)==0 && S_ISREG(init->i_mode)){ pseudo_ok = 1; } iput (init); } if (pseudo_ok){ umsdos_setup_dir_inode (pseudo); Printk (("Activating pseudo root /%s\n",UMSDOS_PSDROOT_NAME)); pseudo_root = pseudo; pseudo->i_count++; pseudo = NULL; } iput (sbin); iput (etc); } iput (pseudo); } } else { MOD_DEC_USE_COUNT; } return sb; }