723 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			723 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* This file contains the procedures that look up path names in the directory
 | |
|  * system and determine the inode number that goes with a given path name.
 | |
|  *
 | |
|  *  The entry points into this file are
 | |
|  *   eat_path:	 the 'main' routine of the path-to-inode conversion mechanism
 | |
|  *   last_dir:	 find the final directory on a given path
 | |
|  *   advance:	 parse one component of a path name
 | |
|  *   search_dir: search a directory for a string and return its inode number
 | |
|  *
 | |
|  * Created (MFS based):
 | |
|  *   February 2010 (Evgeniy Ivanov)
 | |
|  */
 | |
| 
 | |
| #include "fs.h"
 | |
| #include <assert.h>
 | |
| #include <string.h>
 | |
| #include <minix/endpoint.h>
 | |
| #include <sys/stat.h>
 | |
| #include <sys/param.h>
 | |
| #include <sys/types.h>
 | |
| #include "buf.h"
 | |
| #include "inode.h"
 | |
| #include "super.h"
 | |
| #include <minix/vfsif.h>
 | |
| #include <minix/libminixfs.h>
 | |
| 
 | |
| char dot1[2] = ".";	/* used for search_dir to bypass the access */
 | |
| char dot2[3] = "..";	/* permissions for . and ..		    */
 | |
| 
 | |
| static char *get_name(char *name, char string[NAME_MAX+1]);
 | |
| static int ltraverse(struct inode *rip, char *suffix);
 | |
| static int parse_path(ino_t dir_ino, ino_t root_ino, int flags, struct
 | |
| 	inode **res_inop, size_t *offsetp, int *symlinkp);
 | |
| 
 | |
| /*===========================================================================*
 | |
|  *                             fs_lookup				     *
 | |
|  *===========================================================================*/
 | |
| int fs_lookup()
 | |
| {
 | |
|   cp_grant_id_t grant;
 | |
|   int r, r1, flags, symlinks;
 | |
|   unsigned int len;
 | |
|   size_t offset = 0, path_size;
 | |
|   ino_t dir_ino, root_ino;
 | |
|   struct inode *rip;
 | |
| 
 | |
|   grant		= fs_m_in.m_vfs_fs_lookup.grant_path;
 | |
|   path_size	= fs_m_in.m_vfs_fs_lookup.path_size;	/* Size of the buffer */
 | |
|   len		= fs_m_in.m_vfs_fs_lookup.path_len;	/* including terminating nul */
 | |
|   dir_ino	= fs_m_in.m_vfs_fs_lookup.dir_ino;
 | |
|   root_ino	= fs_m_in.m_vfs_fs_lookup.root_ino;
 | |
|   flags		= fs_m_in.m_vfs_fs_lookup.flags;
 | |
| 
 | |
|   /* Check length. */
 | |
|   if(len > sizeof(user_path)) return(E2BIG);	/* too big for buffer */
 | |
|   if(len == 0) return(EINVAL);			/* too small */
 | |
| 
 | |
|   /* Copy the pathname and set up caller's user and group id */
 | |
|   r = sys_safecopyfrom(VFS_PROC_NR, grant, /*offset*/ 0,
 | |
|             (vir_bytes) user_path, (size_t) len);
 | |
|   if(r != OK) return(r);
 | |
| 
 | |
|   /* Verify this is a null-terminated path. */
 | |
|   if(user_path[len - 1] != '\0') return(EINVAL);
 | |
| 
 | |
|   memset(&credentials, 0, sizeof(credentials));
 | |
|   if(!(flags & PATH_GET_UCRED)) { /* Do we have to copy uid/gid credentials? */
 | |
|         caller_uid      = fs_m_in.m_vfs_fs_lookup.uid;
 | |
|         caller_gid      = fs_m_in.m_vfs_fs_lookup.gid;
 | |
|    } else {
 | |
|          if((r=fs_lookup_credentials(&credentials,
 | |
|                &caller_uid, &caller_gid, fs_m_in.m_vfs_fs_lookup.grant_ucred,
 | |
|                fs_m_in.m_vfs_fs_lookup.ucred_size)) != OK)
 | |
|                return r;
 | |
|   }
 | |
| 
 | |
|   /* Lookup inode */
 | |
|   rip = NULL;
 | |
|   r = parse_path(dir_ino, root_ino, flags, &rip, &offset, &symlinks);
 | |
| 
 | |
|   if(symlinks != 0 && (r == ELEAVEMOUNT || r == EENTERMOUNT || r == ESYMLINK)){
 | |
| 	len = strlen(user_path)+1;
 | |
| 	if(len > path_size) return(ENAMETOOLONG);
 | |
| 
 | |
| 	r1 = sys_safecopyto(VFS_PROC_NR, grant, (vir_bytes) 0,
 | |
| 			    (vir_bytes) user_path, (size_t) len);
 | |
| 	if (r1 != OK) return(r1);
 | |
|   }
 | |
| 
 | |
|   if(r == ELEAVEMOUNT || r == ESYMLINK) {
 | |
| 	  /* Report offset and the error */
 | |
| 	  fs_m_out.m_fs_vfs_lookup.offset = offset;
 | |
| 	  fs_m_out.m_fs_vfs_lookup.symloop = symlinks;
 | |
| 
 | |
| 	  return(r);
 | |
|   }
 | |
| 
 | |
|   if (r != OK && r != EENTERMOUNT) return(r);
 | |
| 
 | |
|   fs_m_out.m_fs_vfs_lookup.inode		= rip->i_num;
 | |
|   fs_m_out.m_fs_vfs_lookup.mode			= rip->i_mode;
 | |
|   fs_m_out.m_fs_vfs_lookup.file_size		= rip->i_size;
 | |
|   fs_m_out.m_fs_vfs_lookup.symloop		= symlinks;
 | |
|   fs_m_out.m_fs_vfs_lookup.uid			= rip->i_uid;
 | |
|   fs_m_out.m_fs_vfs_lookup.gid			= rip->i_gid;
 | |
| 
 | |
|   /* This is only valid for block and character specials. But it doesn't
 | |
|    * cause any harm to always set the device field. */
 | |
|   fs_m_out.m_fs_vfs_lookup.device		= (dev_t) rip->i_block[0];
 | |
| 
 | |
|   if(r == EENTERMOUNT) {
 | |
| 	  fs_m_out.m_fs_vfs_lookup.offset	= offset;
 | |
| 	  put_inode(rip); /* Only return a reference to the final object */
 | |
|   }
 | |
| 
 | |
|   return(r);
 | |
| }
 | |
| 
 | |
| 
 | |
| /*===========================================================================*
 | |
|  *                             parse_path				     *
 | |
|  *===========================================================================*/
 | |
| static int parse_path(dir_ino, root_ino, flags, res_inop, offsetp, symlinkp)
 | |
| ino_t dir_ino;
 | |
| ino_t root_ino;
 | |
| int flags;
 | |
| struct inode **res_inop;
 | |
| size_t *offsetp;
 | |
| int *symlinkp;
 | |
| {
 | |
|   /* Parse the path in user_path, starting at dir_ino. If the path is the empty
 | |
|    * string, just return dir_ino. It is upto the caller to treat an empty
 | |
|    * path in a special way. Otherwise, if the path consists of just one or
 | |
|    * more slash ('/') characters, the path is replaced with ".". Otherwise,
 | |
|    * just look up the first (or only) component in path after skipping any
 | |
|    * leading slashes.
 | |
|    */
 | |
|   int r, leaving_mount;
 | |
|   struct inode *rip, *dir_ip;
 | |
|   char *cp, *next_cp; /* component and next component */
 | |
|   char component[NAME_MAX+1];
 | |
| 
 | |
|   /* Start parsing path at the first component in user_path */
 | |
|   cp = user_path;
 | |
| 
 | |
|   /* No symlinks encountered yet */
 | |
|   *symlinkp = 0;
 | |
| 
 | |
|   /* Find starting inode inode according to the request message */
 | |
|   if((rip = find_inode(fs_dev, dir_ino)) == NULL)
 | |
| 	return(ENOENT);
 | |
| 
 | |
|   /* If dir has been removed return ENOENT. */
 | |
|   if (rip->i_links_count == NO_LINK) return(ENOENT);
 | |
| 
 | |
|   dup_inode(rip);
 | |
| 
 | |
|   /* If the given start inode is a mountpoint, we must be here because the file
 | |
|    * system mounted on top returned an ELEAVEMOUNT error. In this case, we must
 | |
|    * only accept ".." as the first path component.
 | |
|    */
 | |
|   leaving_mount = rip->i_mountpoint; /* True iff rip is a mountpoint */
 | |
| 
 | |
|   /* Scan the path component by component. */
 | |
|   while (TRUE) {
 | |
| 	if(cp[0] == '\0') {
 | |
| 		/* We're done; either the path was empty or we've parsed all
 | |
| 		   components of the path */
 | |
| 
 | |
| 		*res_inop = rip;
 | |
| 		*offsetp += cp - user_path;
 | |
| 
 | |
| 		/* Return EENTERMOUNT if we are at a mount point */
 | |
| 		if (rip->i_mountpoint) return(EENTERMOUNT);
 | |
| 
 | |
| 		return(OK);
 | |
| 	}
 | |
| 
 | |
| 	while(cp[0] == '/') cp++;
 | |
| 	next_cp = get_name(cp, component);
 | |
| 	if (next_cp == NULL) {
 | |
| 		put_inode(rip);
 | |
| 		return(err_code);
 | |
| 	}
 | |
| 
 | |
| 	/* Special code for '..'. A process is not allowed to leave a chrooted
 | |
| 	 * environment. A lookup of '..' at the root of a mounted filesystem
 | |
| 	 * has to return ELEAVEMOUNT. In both cases, the caller needs search
 | |
| 	 * permission for the current inode, as it is used as directory.
 | |
| 	 */
 | |
| 	if(strcmp(component, "..") == 0) {
 | |
| 		/* 'rip' is now accessed as directory */
 | |
| 		if ((r = forbidden(rip, X_BIT)) != OK) {
 | |
| 			put_inode(rip);
 | |
| 			return(r);
 | |
| 		}
 | |
| 
 | |
| 		if (rip->i_num == root_ino) {
 | |
| 			cp = next_cp;
 | |
| 			continue;	/* Ignore the '..' at a process' root
 | |
| 					   and move on to the next component */
 | |
| 		}
 | |
| 
 | |
| 		if (rip->i_num == ROOT_INODE && !rip->i_sp->s_is_root) {
 | |
| 			/* Climbing up to parent FS */
 | |
| 
 | |
| 			put_inode(rip);
 | |
| 			*offsetp += cp - user_path;
 | |
| 			return(ELEAVEMOUNT);
 | |
| 		}
 | |
| 	}
 | |
| 
 | |
| 	/* Only check for a mount point if we are not coming from one. */
 | |
| 	if (!leaving_mount && rip->i_mountpoint) {
 | |
| 		/* Going to enter a child FS */
 | |
| 
 | |
| 		*res_inop = rip;
 | |
| 		*offsetp += cp - user_path;
 | |
| 		return(EENTERMOUNT);
 | |
| 	}
 | |
| 
 | |
| 	/* There is more path.  Keep parsing.
 | |
| 	 * If we're leaving a mountpoint, skip directory permission checks.
 | |
| 	 */
 | |
| 	dir_ip = rip;
 | |
| 	rip = advance(dir_ip, leaving_mount ? dot2 : component, CHK_PERM);
 | |
| 	if(err_code == ELEAVEMOUNT || err_code == EENTERMOUNT)
 | |
| 		err_code = OK;
 | |
| 
 | |
| 	if (err_code != OK) {
 | |
| 		put_inode(dir_ip);
 | |
| 		return(err_code);
 | |
| 	}
 | |
| 
 | |
| 	leaving_mount = 0;
 | |
| 
 | |
| 	/* The call to advance() succeeded.  Fetch next component. */
 | |
| 	if (S_ISLNK(rip->i_mode)) {
 | |
| 
 | |
| 		if (next_cp[0] == '\0' && (flags & PATH_RET_SYMLINK)) {
 | |
| 			put_inode(dir_ip);
 | |
| 			*res_inop = rip;
 | |
| 			*offsetp += next_cp - user_path;
 | |
| 			return(OK);
 | |
| 		}
 | |
| 
 | |
| 		/* Extract path name from the symlink file */
 | |
| 		r = ltraverse(rip, next_cp);
 | |
| 		next_cp = user_path;
 | |
| 		*offsetp = 0;
 | |
| 
 | |
| 		/* Symloop limit reached? */
 | |
| 		if (++(*symlinkp) > _POSIX_SYMLOOP_MAX)
 | |
| 			r = ELOOP;
 | |
| 
 | |
| 		if (r != OK) {
 | |
| 			put_inode(dir_ip);
 | |
| 			put_inode(rip);
 | |
| 			return(r);
 | |
| 		}
 | |
| 
 | |
| 		if (next_cp[0] == '/') {
 | |
|                         put_inode(dir_ip);
 | |
|                         put_inode(rip);
 | |
|                         return(ESYMLINK);
 | |
| 		}
 | |
| 
 | |
| 		put_inode(rip);
 | |
| 		dup_inode(dir_ip);
 | |
| 		rip = dir_ip;
 | |
| 	}
 | |
| 
 | |
| 	put_inode(dir_ip);
 | |
| 	cp = next_cp; /* Process subsequent component in next round */
 | |
|   }
 | |
| 
 | |
| }
 | |
| 
 | |
| 
 | |
| /*===========================================================================*
 | |
|  *                             ltraverse				     *
 | |
|  *===========================================================================*/
 | |
| static int ltraverse(rip, suffix)
 | |
| register struct inode *rip;	/* symbolic link */
 | |
| char *suffix;			/* current remaining path. Has to point in the
 | |
| 				 * user_path buffer
 | |
| 				 */
 | |
| {
 | |
| /* Traverse a symbolic link. Copy the link text from the inode and insert
 | |
|  * the text into the path. Return error code or report success. Base
 | |
|  * directory has to be determined according to the first character of the
 | |
|  * new pathname.
 | |
|  */
 | |
| 
 | |
|   size_t llen;		/* length of link */
 | |
|   size_t slen;		/* length of suffix */
 | |
|   struct buf *bp;	/* buffer containing link text */
 | |
|   const char *sp;	/* start of link text */
 | |
| 
 | |
|   llen = (size_t) rip->i_size;
 | |
| 
 | |
|   if (llen >= MAX_FAST_SYMLINK_LENGTH) {
 | |
| 	/* normal symlink */
 | |
| 	if(!(bp = get_block_map(rip, 0)))
 | |
| 		return(EIO);
 | |
| 	sp = b_data(bp);
 | |
|   } else {
 | |
| 	/* fast symlink, stored in inode */
 | |
| 	sp = (const char*) rip->i_block;
 | |
|   }
 | |
| 
 | |
|   slen = strlen(suffix);
 | |
| 
 | |
|   /* The path we're parsing looks like this:
 | |
|    * /already/processed/path/<link> or
 | |
|    * /already/processed/path/<link>/not/yet/processed/path
 | |
|    * After expanding the <link>, the path will look like
 | |
|    * <expandedlink> or
 | |
|    * <expandedlink>/not/yet/processed
 | |
|    * In both cases user_path must have enough room to hold <expandedlink>.
 | |
|    * However, in the latter case we have to move /not/yet/processed to the
 | |
|    * right place first, before we expand <link>. When strlen(<expandedlink>) is
 | |
|    * smaller than strlen(/already/processes/path), we move the suffix to the
 | |
|    * left. Is strlen(<expandedlink>) greater then we move it to the right. Else
 | |
|    * we do nothing.
 | |
|    */
 | |
| 
 | |
|   if (slen > 0) { /* Do we have path after the link? */
 | |
| 	/* For simplicity we require that suffix starts with a slash */
 | |
| 	if (suffix[0] != '/') {
 | |
| 		panic("ltraverse: suffix does not start with a slash");
 | |
| 	}
 | |
| 
 | |
| 	/* To be able to expand the <link>, we have to move the 'suffix'
 | |
| 	 * to the right place.
 | |
| 	 */
 | |
| 	if (slen + llen + 1 > sizeof(user_path))
 | |
| 		return(ENAMETOOLONG);/* <expandedlink>+suffix+\0 does not fit*/
 | |
| 	if ((unsigned)(suffix - user_path) != llen) {
 | |
| 		/* Move suffix left or right if needed */
 | |
| 		memmove(&user_path[llen], suffix, slen+1);
 | |
| 	}
 | |
|   } else {
 | |
| 	if (llen + 1 > sizeof(user_path))
 | |
| 		return(ENAMETOOLONG); /* <expandedlink> + \0 does not fit */
 | |
| 
 | |
| 	/* Set terminating nul */
 | |
| 	user_path[llen]= '\0';
 | |
|   }
 | |
| 
 | |
|   /* Everything is set, now copy the expanded link to user_path */
 | |
|   memmove(user_path, sp, llen);
 | |
| 
 | |
|   if (llen >= MAX_FAST_SYMLINK_LENGTH)
 | |
| 	put_block(bp, DIRECTORY_BLOCK);
 | |
| 
 | |
|   return(OK);
 | |
| }
 | |
| 
 | |
| 
 | |
| /*===========================================================================*
 | |
|  *				advance					     *
 | |
|  *===========================================================================*/
 | |
| struct inode *advance(dirp, string, chk_perm)
 | |
| struct inode *dirp;		/* inode for directory to be searched */
 | |
| char string[NAME_MAX + 1];	/* component name to look for */
 | |
| int chk_perm;			/* check permissions when string is looked up*/
 | |
| {
 | |
| /* Given a directory and a component of a path, look up the component in
 | |
|  * the directory, find the inode, open it, and return a pointer to its inode
 | |
|  * slot.
 | |
|  */
 | |
|   ino_t numb;
 | |
|   struct inode *rip;
 | |
| 
 | |
|   /* If 'string' is empty, return an error. */
 | |
|   if (string[0] == '\0') {
 | |
| 	err_code = ENOENT;
 | |
| 	return(NULL);
 | |
|   }
 | |
| 
 | |
|   /* Check for NULL. */
 | |
|   if (dirp == NULL) return(NULL);
 | |
| 
 | |
|   /* If 'string' is not present in the directory, signal error. */
 | |
|   if ( (err_code = search_dir(dirp, string, &numb, LOOK_UP,
 | |
| 			      chk_perm, 0)) != OK) {
 | |
| 	return(NULL);
 | |
|   }
 | |
| 
 | |
|   /* The component has been found in the directory.  Get inode. */
 | |
|   if ( (rip = get_inode(dirp->i_dev, (int) numb)) == NULL)  {
 | |
| 	return(NULL);
 | |
|   }
 | |
| 
 | |
|   /* The following test is for "mountpoint/.." where mountpoint is a
 | |
|    * mountpoint. ".." will refer to the root of the mounted filesystem,
 | |
|    * but has to become a reference to the parent of the 'mountpoint'
 | |
|    * directory.
 | |
|    *
 | |
|    * This case is recognized by the looked up name pointing to a
 | |
|    * root inode, and the directory in which it is held being a
 | |
|    * root inode, _and_ the name[1] being '.'. (This is a test for '..'
 | |
|    * and excludes '.'.)
 | |
|    */
 | |
|   if (rip->i_num == ROOT_INODE) {
 | |
| 	  if (dirp->i_num == ROOT_INODE) {
 | |
| 		  if (string[1] == '.') {
 | |
| 			  if (!rip->i_sp->s_is_root) {
 | |
| 				  /* Climbing up mountpoint */
 | |
| 				  err_code = ELEAVEMOUNT;
 | |
| 			  }
 | |
| 		  }
 | |
| 	  }
 | |
|   }
 | |
| 
 | |
|   /* See if the inode is mounted on.  If so, switch to root directory of the
 | |
|    * mounted file system.  The super_block provides the linkage between the
 | |
|    * inode mounted on and the root directory of the mounted file system.
 | |
|    */
 | |
|   if (rip->i_mountpoint) {
 | |
| 	  /* Mountpoint encountered, report it */
 | |
| 	  err_code = EENTERMOUNT;
 | |
|   }
 | |
| 
 | |
|   return(rip);
 | |
| }
 | |
| 
 | |
| 
 | |
| /*===========================================================================*
 | |
|  *				get_name				     *
 | |
|  *===========================================================================*/
 | |
| static char *get_name(path_name, string)
 | |
| char *path_name;		/* path name to parse */
 | |
| char string[NAME_MAX+1];	/* component extracted from 'old_name' */
 | |
| {
 | |
| /* Given a pointer to a path name in fs space, 'path_name', copy the first
 | |
|  * component to 'string' (truncated if necessary, always nul terminated).
 | |
|  * A pointer to the string after the first component of the name as yet
 | |
|  * unparsed is returned.  Roughly speaking,
 | |
|  * 'get_name' = 'path_name' - 'string'.
 | |
|  *
 | |
|  * This routine follows the standard convention that /usr/ast, /usr//ast,
 | |
|  * //usr///ast and /usr/ast/ are all equivalent.
 | |
|  *
 | |
|  * If len of component is greater, than allowed, then return 0.
 | |
|  */
 | |
|   size_t len;
 | |
|   char *cp, *ep;
 | |
| 
 | |
|   cp = path_name;
 | |
| 
 | |
|   /* Skip leading slashes */
 | |
|   while (cp[0] == '/') cp++;
 | |
| 
 | |
|   /* Find the end of the first component */
 | |
|   ep = cp;
 | |
|   while(ep[0] != '\0' && ep[0] != '/')
 | |
| 	ep++;
 | |
| 
 | |
|   len = (size_t) (ep - cp);
 | |
| 
 | |
|   if (len > NAME_MAX || len > EXT2_NAME_MAX) {
 | |
|   	err_code = ENAMETOOLONG;
 | |
| 	return(NULL);
 | |
|   }
 | |
| 
 | |
|   /* Special case of the string at cp is empty */
 | |
|   if (len == 0)
 | |
| 	strlcpy(string, ".", NAME_MAX + 1);  /* Return "." */
 | |
|   else {
 | |
| 	memcpy(string, cp, len);
 | |
| 	string[len]= '\0';
 | |
|   }
 | |
| 
 | |
|   return(ep);
 | |
| }
 | |
| 
 | |
| 
 | |
| /*===========================================================================*
 | |
|  *				search_dir				     *
 | |
|  *===========================================================================*/
 | |
| int search_dir(ldir_ptr, string, numb, flag, check_permissions, ftype)
 | |
| register struct inode *ldir_ptr; /* ptr to inode for dir to search */
 | |
| const char string[NAME_MAX + 1];	 /* component to search for */
 | |
| ino_t *numb;			 /* pointer to inode number */
 | |
| int flag;			 /* LOOK_UP, ENTER, DELETE or IS_EMPTY */
 | |
| int check_permissions;		 /* check permissions when flag is !IS_EMPTY */
 | |
| int ftype;			 /* used when ENTER and
 | |
| 				  * INCOMPAT_FILETYPE */
 | |
| {
 | |
| /* This function searches the directory whose inode is pointed to by 'ldip':
 | |
|  * if (flag == ENTER)  enter 'string' in the directory with inode # '*numb';
 | |
|  * if (flag == DELETE) delete 'string' from the directory;
 | |
|  * if (flag == LOOK_UP) search for 'string' and return inode # in 'numb';
 | |
|  * if (flag == IS_EMPTY) return OK if only . and .. in dir else ENOTEMPTY;
 | |
|  *
 | |
|  *    if 'string' is dot1 or dot2, no access permissions are checked.
 | |
|  */
 | |
| 
 | |
|   register struct ext2_disk_dir_desc  *dp = NULL;
 | |
|   register struct ext2_disk_dir_desc  *prev_dp = NULL;
 | |
|   register struct buf *bp = NULL;
 | |
|   int i, r, e_hit, t, match;
 | |
|   mode_t bits;
 | |
|   off_t pos;
 | |
|   unsigned new_slots;
 | |
|   int extended = 0;
 | |
|   int required_space = 0;
 | |
|   int string_len = 0;
 | |
| 
 | |
|   /* If 'ldir_ptr' is not a pointer to a dir inode, error. */
 | |
|   if ( (ldir_ptr->i_mode & I_TYPE) != I_DIRECTORY)  {
 | |
| 	return(ENOTDIR);
 | |
|   }
 | |
| 
 | |
|   r = OK;
 | |
| 
 | |
|   if (flag != IS_EMPTY) {
 | |
| 	bits = (flag == LOOK_UP ? X_BIT : W_BIT | X_BIT);
 | |
| 
 | |
| 	if (string == dot1 || string == dot2) {
 | |
| 		if (flag != LOOK_UP) r = read_only(ldir_ptr);
 | |
| 				     /* only a writable device is required. */
 | |
|         } else if(check_permissions) {
 | |
| 		r = forbidden(ldir_ptr, bits); /* check access permissions */
 | |
| 	}
 | |
|   }
 | |
|   if (r != OK) return(r);
 | |
| 
 | |
|   new_slots = 0;
 | |
|   e_hit = FALSE;
 | |
|   match = 0;    	/* set when a string match occurs */
 | |
|   pos = 0;
 | |
| 
 | |
|   if (flag == ENTER) {
 | |
| 	string_len = strlen(string);
 | |
| 	required_space = MIN_DIR_ENTRY_SIZE + string_len;
 | |
| 	required_space += (required_space & 0x03) == 0 ? 0 :
 | |
| 			     (DIR_ENTRY_ALIGN - (required_space & 0x03) );
 | |
| 
 | |
| 	if (ldir_ptr->i_last_dpos < ldir_ptr->i_size &&
 | |
| 	    ldir_ptr->i_last_dentry_size <= required_space)
 | |
| 		pos = ldir_ptr->i_last_dpos;
 | |
|   }
 | |
| 
 | |
|   for (; pos < ldir_ptr->i_size; pos += ldir_ptr->i_sp->s_block_size) {
 | |
| 	/* Since directories don't have holes, 'b' cannot be NO_BLOCK. */
 | |
| 	if(!(bp = get_block_map(ldir_ptr,
 | |
| 	   rounddown(pos, ldir_ptr->i_sp->s_block_size))))
 | |
| 		panic("get_block returned NO_BLOCK");
 | |
| 
 | |
| 	prev_dp = NULL; /* New block - new first dentry, so no prev. */
 | |
| 
 | |
| 	/* Search a directory block.
 | |
| 	 * Note, we set prev_dp at the end of the loop.
 | |
| 	 */
 | |
| 	for (dp = (struct ext2_disk_dir_desc*) &b_data(bp);
 | |
| 	     CUR_DISC_DIR_POS(dp, &b_data(bp)) < ldir_ptr->i_sp->s_block_size;
 | |
| 	     dp = NEXT_DISC_DIR_DESC(dp) ) {
 | |
| 		/* Match occurs if string found. */
 | |
| 		if (flag != ENTER && dp->d_ino != NO_ENTRY) {
 | |
| 			if (flag == IS_EMPTY) {
 | |
| 				/* If this test succeeds, dir is not empty. */
 | |
| 				if (ansi_strcmp(dp->d_name, ".", dp->d_name_len) != 0 &&
 | |
| 				    ansi_strcmp(dp->d_name, "..", dp->d_name_len) != 0) match = 1;
 | |
| 			} else {
 | |
| 				if (ansi_strcmp(dp->d_name, string, dp->d_name_len) == 0){
 | |
| 					match = 1;
 | |
| 				}
 | |
| 			}
 | |
| 		}
 | |
| 
 | |
| 		if (match) {
 | |
| 			/* LOOK_UP or DELETE found what it wanted. */
 | |
| 			r = OK;
 | |
| 			if (flag == IS_EMPTY) r = ENOTEMPTY;
 | |
| 			else if (flag == DELETE) {
 | |
| 				if (dp->d_name_len >= sizeof(ino_t)) {
 | |
| 					/* Save d_ino for recovery. */
 | |
| 					t = dp->d_name_len - sizeof(ino_t);
 | |
| 					*((ino_t *) &dp->d_name[t])= dp->d_ino;
 | |
| 				}
 | |
| 				dp->d_ino = NO_ENTRY;	/* erase entry */
 | |
| 				lmfs_markdirty(bp);
 | |
| 
 | |
| 				/* If we don't support HTree (directory index),
 | |
| 				 * which is fully compatible ext2 feature,
 | |
| 				 * we should reset EXT2_INDEX_FL, when modify
 | |
| 				 * linked directory structure.
 | |
| 				 *
 | |
| 				 * @TODO: actually we could just reset it for
 | |
| 				 * each directory, but I added if() to not
 | |
| 				 * forget about it later, when add HTree
 | |
| 				 * support.
 | |
| 				 */
 | |
| 				if (!HAS_COMPAT_FEATURE(ldir_ptr->i_sp,
 | |
| 							COMPAT_DIR_INDEX))
 | |
| 					ldir_ptr->i_flags &= ~EXT2_INDEX_FL;
 | |
| 				if (pos < ldir_ptr->i_last_dpos) {
 | |
| 					ldir_ptr->i_last_dpos = pos;
 | |
| 					ldir_ptr->i_last_dentry_size =
 | |
| 						conv2(le_CPU, dp->d_rec_len);
 | |
| 				}
 | |
| 				ldir_ptr->i_update |= CTIME | MTIME;
 | |
| 				ldir_ptr->i_dirt = IN_DIRTY;
 | |
| 				/* Now we have cleared dentry, if it's not
 | |
| 				 * the first one, merge it with previous one.
 | |
| 				 * Since we assume, that existing dentry must be
 | |
| 				 * correct, there is no way to spann a data block.
 | |
| 				 */
 | |
| 				if (prev_dp) {
 | |
| 					u16_t temp = conv2(le_CPU,
 | |
| 							prev_dp->d_rec_len);
 | |
| 					temp += conv2(le_CPU,
 | |
| 							dp->d_rec_len);
 | |
| 					prev_dp->d_rec_len = conv2(le_CPU,
 | |
| 							temp);
 | |
| 				}
 | |
| 			} else {
 | |
| 				/* 'flag' is LOOK_UP */
 | |
| 				*numb = (ino_t) conv4(le_CPU, dp->d_ino);
 | |
| 			}
 | |
| 			assert(lmfs_dev(bp) != NO_DEV);
 | |
| 			put_block(bp, DIRECTORY_BLOCK);
 | |
| 			return(r);
 | |
| 		}
 | |
| 
 | |
| 		/* Check for free slot for the benefit of ENTER. */
 | |
| 		if (flag == ENTER && dp->d_ino == NO_ENTRY) {
 | |
| 			/* we found a free slot, check if it has enough space */
 | |
| 			if (required_space <= conv2(le_CPU, dp->d_rec_len)) {
 | |
| 				e_hit = TRUE;	/* we found a free slot */
 | |
| 				break;
 | |
| 			}
 | |
| 		}
 | |
| 		/* Can we shrink dentry? */
 | |
| 		if (flag == ENTER && required_space <= DIR_ENTRY_SHRINK(dp)) {
 | |
| 			/* Shrink directory and create empty slot, now
 | |
| 			 * dp->d_rec_len = DIR_ENTRY_ACTUAL_SIZE + DIR_ENTRY_SHRINK.
 | |
| 			 */
 | |
| 			int new_slot_size = conv2(le_CPU, dp->d_rec_len);
 | |
| 			int actual_size = DIR_ENTRY_ACTUAL_SIZE(dp);
 | |
| 			new_slot_size -= actual_size;
 | |
| 			dp->d_rec_len = conv2(le_CPU, actual_size);
 | |
| 			dp = NEXT_DISC_DIR_DESC(dp);
 | |
| 			dp->d_rec_len = conv2(le_CPU, new_slot_size);
 | |
| 			/* if we fail before writing real ino */
 | |
| 			dp->d_ino = NO_ENTRY;
 | |
| 			lmfs_markdirty(bp);
 | |
| 			e_hit = TRUE;	/* we found a free slot */
 | |
| 			break;
 | |
| 		}
 | |
| 
 | |
| 		prev_dp = dp;
 | |
| 	}
 | |
| 
 | |
| 	/* The whole block has been searched or ENTER has a free slot. */
 | |
| 	assert(lmfs_dev(bp) != NO_DEV);
 | |
| 	if (e_hit) break;	/* e_hit set if ENTER can be performed now */
 | |
| 	put_block(bp, DIRECTORY_BLOCK); /* otherwise, continue searching dir */
 | |
|   }
 | |
| 
 | |
|   /* The whole directory has now been searched. */
 | |
|   if (flag != ENTER) {
 | |
| 	return(flag == IS_EMPTY ? OK : ENOENT);
 | |
|   }
 | |
| 
 | |
|   /* When ENTER next time, start searching for free slot from
 | |
|    * i_last_dpos. It gives solid performance improvement.
 | |
|    */
 | |
|   ldir_ptr->i_last_dpos = pos;
 | |
|   ldir_ptr->i_last_dentry_size = required_space;
 | |
| 
 | |
|   /* This call is for ENTER.  If no free slot has been found so far, try to
 | |
|    * extend directory.
 | |
|    */
 | |
|   if (e_hit == FALSE) { /* directory is full and no room left in last block */
 | |
| 	new_slots++;		/* increase directory size by 1 entry */
 | |
| 	if ( (bp = new_block(ldir_ptr, ldir_ptr->i_size)) == NULL)
 | |
| 		return(err_code);
 | |
| 	dp = (struct ext2_disk_dir_desc*) &b_data(bp);
 | |
| 	dp->d_rec_len = conv2(le_CPU, ldir_ptr->i_sp->s_block_size);
 | |
| 	dp->d_name_len = DIR_ENTRY_MAX_NAME_LEN(dp); /* for failure */
 | |
| 	extended = 1;
 | |
|   }
 | |
| 
 | |
|   /* 'bp' now points to a directory block with space. 'dp' points to slot. */
 | |
|   dp->d_name_len = string_len;
 | |
|   for (i = 0; i < NAME_MAX && i < dp->d_name_len && string[i]; i++)
 | |
| 	dp->d_name[i] = string[i];
 | |
|   dp->d_ino = (int) conv4(le_CPU, *numb);
 | |
|   if (HAS_INCOMPAT_FEATURE(ldir_ptr->i_sp, INCOMPAT_FILETYPE)) {
 | |
| 	/* Convert ftype (from inode.i_mode) to dp->d_file_type */
 | |
| 	if (ftype == I_REGULAR)
 | |
| 		dp->d_file_type = EXT2_FT_REG_FILE;
 | |
| 	else if (ftype == I_DIRECTORY)
 | |
| 		dp->d_file_type = EXT2_FT_DIR;
 | |
| 	else if (ftype == I_SYMBOLIC_LINK)
 | |
| 		dp->d_file_type = EXT2_FT_SYMLINK;
 | |
| 	else if (ftype == I_BLOCK_SPECIAL)
 | |
| 		dp->d_file_type = EXT2_FT_BLKDEV;
 | |
| 	else if (ftype == I_CHAR_SPECIAL)
 | |
| 		dp->d_file_type = EXT2_FT_CHRDEV;
 | |
| 	else if (ftype == I_NAMED_PIPE)
 | |
| 		dp->d_file_type = EXT2_FT_FIFO;
 | |
| 	else
 | |
| 		dp->d_file_type = EXT2_FT_UNKNOWN;
 | |
|   }
 | |
|   lmfs_markdirty(bp);
 | |
|   put_block(bp, DIRECTORY_BLOCK);
 | |
|   ldir_ptr->i_update |= CTIME | MTIME;	/* mark mtime for update later */
 | |
|   ldir_ptr->i_dirt = IN_DIRTY;
 | |
| 
 | |
|   if (new_slots == 1) {
 | |
| 	ldir_ptr->i_size += (off_t) conv2(le_CPU, dp->d_rec_len);
 | |
| 	/* Send the change to disk if the directory is extended. */
 | |
| 	if (extended) rw_inode(ldir_ptr, WRITING);
 | |
|   }
 | |
|   return(OK);
 | |
| 
 | |
| }
 | 
