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fsdb_ufs(1M)		System Administration Commands		  fsdb_ufs(1M)

NAME
       fsdb_ufs - ufs file system debugger

SYNOPSIS
       fsdb -F ufs [generic_options] [specific_options] special

DESCRIPTION
       The  fsdb_ufs  command is an interactive tool that can be used to patch
       up a damaged UFS file system. It has conversions to translate block and
       i-numbers  into	their corresponding disk addresses.  Also included are
       mnemonic offsets to access different parts of an inode.	These  greatly
       simplify	 the process of correcting control block entries or descending
       the file system tree.

       fsdb contains several error-checking routines to verify inode and block
       addresses. These can be disabled if necessary by invoking fsdb with the
       -o option or by the use of the o command.

       fsdb reads a block at a time and will therefore work with raw  as  well
       as  block  I/O  devices.	 A buffer management routine is used to retain
       commonly used blocks of data in order to reduce the number of read sys‐
       tem  calls.  All	 assignment  operations	 result in an immediate write-
       through of the corresponding block. Note that in order  to  modify  any
       portion of the disk, fsdb must be invoked with the w option.

       Wherever	 possible,  adb-like  syntax was adopted to promote the use of
       fsdb through familiarity.

OPTIONS
       The following option is supported:

       -o	Specify UFS file system specific options. These options can be
		any  combination of the following separated by commas (with no
		intervening spaces). The options available are:

		?		Display usage

		o		Override some error conditions

		p='string'	set prompt to string

		w		open for write

USAGE
       Numbers are considered hexadecimal by default. However,	the  user  has
       control	over how data is to be displayed or accepted. The base command
       will display or set the input/output base. Once	set,  all  input  will
       default	to  this  base	and all output will be shown in this base. The
       base can be overridden temporarily for input by	preceding  hexadecimal
       numbers	with  '0x', preceding decimal numbers with '0t', or octal num‐
       bers with '0'. Hexadecimal numbers beginning with a-f or	 A-F  must  be
       preceded with '0x' to distinguish them from commands.

       Disk addressing by fsdb is at the byte level. However, fsdb offers many
       commands to convert a desired inode, directory entry, block, superblock
       and  so	forth to a byte address. Once the address has been calculated,
       fsdb will record the result in dot (.).

       Several global values are maintained by fsdb:

	 ·  the current base (referred to as base),

	 ·  the current address (referred to as dot),

	 ·  the current inode (referred to as inode),

	 ·  the current count (referred to as count),

	 ·  and the current type (referred to as type).

       Most commands use the preset value of dot in their execution. For exam‐
       ple,

	      > 2:inode

       will  first  set	 the value of dot to 2, ':', will alert the start of a
       command, and the inode command will set inode to 2. A count  is	speci‐
       fied after a ','. Once set, count will remain at this value until a new
       command is encountered which will then reset the value back to  1  (the
       default). So, if

	      > 2000,400/X

       is  typed,  400 hex longs are listed from 2000, and when completed, the
       value of dot will be 2000 + 400 * sizeof (long). If a  RETURN  is  then
       typed,  the  output  routine will use the current values of dot, count,
       and type and display 400 more hex longs.	 A '*' will cause  the	entire
       block to be displayed.

       End  of fragment, block and file are maintained by fsdb.	 When display‐
       ing data as fragments or blocks, an error  message  will	 be  displayed
       when  the  end  of  fragment  or block is reached. When displaying data
       using the db, ib, directory, or file commands an error message is  dis‐
       played  if  the	end of file is reached. This is mainly needed to avoid
       passing the end of a directory or file and getting unknown and unwanted
       results.

       An example showing several commands and the use of  RETURN would be:

	      > 2:ino; 0:dir?d
		    or
	      > 2:ino; 0:db:block?d

       The  two	 examples  are	synonymous  for getting to the first directory
       entry of the root of  the  file	system.	 Once  there,  any  subsequent
       RETURN (or +, -) will advance to subsequent entries. Note that

	      > 2:inode; :ls
		    or
	      > :ls /

       is again synonymous.

   Expressions
       The symbols recognized by fsdb are:

       RETURN	       update  the  value  of dot by the current value of type
		       and display using the current value of count.

       #	       numeric expressions may be composed of +, -, *,	and  %
		       operators  (evaluated left to right) and may use paren‐
		       theses. Once evaluated, the value of dot is updated.

       , count	       count indicator. The global  value  of  count  will  be
		       updated	to count. The value of count will remain until
		       a new command is run. A count  specifier	 of  '*'  will
		       attempt	to  show  a blocks's worth of information. The
		       default for count is 1.

       ? f	       display in structured style with	 format	 specifier  f.
		       See FormattedOutput.

       / f	       display	in  unstructured style with format specifier f
		       See FormattedOutput.

       .	       the value of dot.

       +e	       increment the value of dot by  the  expression  e.  The
		       amount actually incremented is dependent on the size of
		       type:

		       dot = dot + e * sizeof (type)

		       The default for e is 1.

       -e	       decrement the value of dot by the expression e. See  +.

       *e	       multiply the value of dot by the expression  e.	Multi‐
		       plication  and  division	 don't use type.  In the above
		       calculation of dot, consider the sizeof(type) to be 1.

       %e	       divide the value of dot by the expression e. See	 *.

       < name	       restore an address saved in register name. name must be
		       a single letter or digit.

       > name	       save an address in register name. name must be a single
		       letter or digit.

       = f	       display indicator. If f is a legitimate	format	speci‐
		       fier. then the value of dot is displayed using the for‐
		       mat  specifier  f.  See	 FormattedOutput.   Otherwise,
		       assignment is assumed See  =.

       = [s] [e]       assignment indicator. The address pointed to by dot has
		       its contents changed to the value of the	 expression  e
		       or to the ASCII representation of the quoted (") string
		       s. This may be useful for changing directory  names  or
		       ASCII file information.

       =+ e	       incremental  assignment.	 The address pointed to by dot
		       has its contents incremented by expression e.

       =- e	       decremental assignment. The address pointed to  by  dot
		       has its contents decremented by expression e.

   Commands
       A  command  must be prefixed by a ':' character. Only enough letters of
       the command to uniquely distinguish it are  needed.  Multiple  commands
       may be entered on one line by separating them by a  SPACE, TAB or ';'.

       In  order  to view a potentially unmounted disk in a reasonable manner,
       fsdb offers the cd, pwd, ls and find  commands.	The  functionality  of
       these  commands	substantially  matches those of its UNIX counterparts.
       See individual commands for details. The '*', '?', and '[-]' wild  card
       characters are available.

       base=b			       display	or  set base. As stated above,
				       all input and output is governed by the
				       current	base.  If  the	=b is omitted,
				       the current base is  displayed.	Other‐
				       wise,  the  current  base  is set to b.
				       Note that this is interpreted using the
				       old  value  of  base, so to ensure cor‐
				       rectness use the	 '0',  '0t',  or  '0x'
				       prefix  when  changing  the  base.  The
				       default for base is hexadecimal.

       block			       convert the value of  dot  to  a	 block
				       address.

       cd dir			       change  the current directory to direc‐
				       tory dir. The current values  of	 inode
				       and  dot are also updated. If no dir is
				       specified, then change  directories  to
				       inode 2 ("/").

       cg			       convert	the value of dot to a cylinder
				       group.

       directory		       If the current inode  is	 a  directory,
				       then the value of dot is converted to a
				       directory slot offset in that directory
				       and dot now points to this entry.

       file			       the value of dot is taken as a relative
				       block count from the beginning  of  the
				       file.  The  value  of dot is updated to
				       the first byte of this block.

       find dir[ -name n] [-inum i]    find files by name  or  i-number.  find
				       recursively  searches directory dir and
				       below  for  filenames  whose   i-number
				       matches i or whose name matches pattern
				       n.  Note	 that  only  one  of  the  two
				       options (-name or -inum) may be used at
				       one  time.  Also,  the  -print  is  not
				       needed or accepted.

       fill=p			       fill  an	 area  of disk with pattern p.
				       The area of disk is  delimited  by  dot
				       and count.

       fragment			       convert	the value of dot to a fragment
				       address. The  only  difference  between
				       the fragment command and the block com‐
				       mand is the amount that is able	to  be
				       displayed.

       inode			       convert	the  value  of dot to an inode
				       address.	 If  successful,  the  current
				       value  of inode will be updated as well
				       as the value of dot.  As	 a  convenient
				       shorthand,  if  ':inode' appears at the
				       beginning of the line, the value of dot
				       is  set	to  the current inode and that
				       inode is displayed in inode format.

       log_chk			       run through the valid log entries with‐
				       out printing any information and verify
				       the layout.

       log_delta		       count the number	 of  deltas  into  the
				       log,  using the value of dot as an off‐
				       set into the log. No checking  is  done
				       to  make sure that offset is within the
				       head/tail offsets.

       log_head			       display the  header  information	 about
				       the file system logging. This shows the
				       block allocation for the	 log  and  the
				       data structures on the disk.

       log_otodb		       return  the physical disk block number,
				       using the value of  dot	as  an	offset
				       into the log.

       log_show			       display	all deltas between  the begin‐
				       ning of the log (BOL) and  the  end  of
				       the log (EOL).

       ls			       [ -R ] [ -l ] pat1 pat2...  list direc‐
				       tories or files. If no file  is	speci‐
				       fied, the current directory is assumed.
				       Either or both of the  options  may  be
				       used  (but,  if used, must be specified
				       before the filename specifiers).	 Also,
				       as  stated  above, wild card characters
				       are available  and  multiple  arguments
				       may  be	given.	The long listing shows
				       only the i-number and the name; use the
				       inode  command  with  '?i'  to get more
				       information.

       override			       toggle  the  value  of  override.  Some
				       error  conditions  may  be overriden if
				       override is toggled on.

       prompt p			       change the fsdb prompt to p. p must  be
				       surrounded by (")s.

       pwd			       display the current working directory.

       quit			       quit fsdb.

       sb			       the value of dot is taken as a cylinder
				       group number and then converted to  the
				       address	 of  the  superblock  in  that
				       cylinder group. As a  shorthand,	 ':sb'
				       at the beginning of a line will set the
				       value of dot to the superblock and dis‐
				       play it in superblock format.

       shadow			       if the current inode is a shadow inode,
				       then the value of dot  is  set  to  the
				       beginning of the shadow inode data.

       !			       escape to shell

   Inode Commands
       In addition to the above commands, there are several commands that deal
       with inode fields and operate directly on the current inode (they still
       require the ':'). They may be used to more easily display or change the
       particular fields. The value of dot is only used by the ':db' and ':ib'
       commands.  Upon	completion of the command, the value of dot is changed
       to point to that particular field. For example,

	      > :ln=+1

       would increment the link count of the current inode and set  the	 value
       of dot to the address of the link count field.

       at	access time.

       bs	block size.

       ct	creation time.

       db	use  the  current  value of dot as a direct block index, where
		direct blocks number from 0 - 11.  In  order  to  display  the
		block itself, you need to 'pipe' this result into the block or
		fragment command. For example,

		     > 1:db:block,20/X

		would get the contents of data block field 1  from  the	 inode
		and convert it to a block address. 20 longs are then displayed
		in hexadecimal. See FormattedOutput.

       gid	group id.

       ib	use the current value of dot as an indirect block index	 where
		indirect  blocks  number  from	0  - 2. This will only get the
		indirect block itself (the block containing  the  pointers  to
		the actual blocks). Use the file command and start at block 12
		to get to the actual blocks.

       ln	link count.

       mt	modification time.

       md	mode.

       maj	major device number.

       min	minor device number.

       nm	although listed here, this command actually  operates  on  the
		directory  name	 field.	 Once  poised at the desired directory
		entry (using the directory command), this command  will	 allow
		you to change or display the directory name.  For example,

		> 7:dir:nm="foo"

		will  get  the	7th  directory	entry of the current inode and
		change its name to foo. Note that names cannot be made	larger
		than  the  field  is  set  up  for. If an attempt is made, the
		string is truncated to fit  and	 a  warning  message  to  this
		effect is displayed.

       si	shadow inode.

       sz	file size.

       uid	user id.

   Formatted Output
       There  are two styles and many format types.  The two styles are struc‐
       tured and unstructured. Structured output is used  to  display  inodes,
       directories,  superblocks and the like. Unstructured displays raw data.
       The following shows the different ways of displaying:

       ?
		c	 display as cylinder groups

		i	 display as inodes

		d	 display as directories

		s	 display as superblocks

		S	 display as shadow inode data

       /
		b	 display as bytes

		c	 display as characters

		o O	 display as octal shorts or longs

		d D	 display as decimal shorts or longs

		x X	 display as hexadecimal shorts or longs

		The format specifier immediately follows the '/' or '?'	 char‐
		acter.	 The  values displayed by '/b' and all '?' formats are
		displayed in the current base.	Also,  type  is	 appropriately
		updated upon completion.

EXAMPLES
       Example 1: Displaying in Decimal

       The following command displays 2010 in decimal (use of fsdb as a calcu‐
       lator for complex arithmetic):

       > 2000+400%(20+20)=D

       Example 2: Displaying an i-number in Inode Format

       The following command displays i-number 386 in an  inode	 format.  This
       now becomes the current inode:

       > 386:ino?i

       Example 3: Changing the Link Count

       The  following  command changes the link count for the current inode to
       4:

       > :ln=4

       Example 4: Incrementing the Link Count

       The following command increments the link count by 1:

       > :ln=+1

       Example 5: Displaying the Creation Time

       The following command displays the creation time as a hexadecimal long:

       > :ct=X

       Example 6: Displaying the Modification Time

       The following command displays the modification time in time format:

       > :mt=t

       Example 7: Displaying in ASCII

       The following command displays in ASCII, block zero of the file associ‐
       ated with the current inode:

       > 0:file/c

       Example 8: Displaying the First Block's Worth of Directorty Entries

       The  following  command	displays  the first block's worth of directory
       entries for the root inode of this file system.	It  will  stop	prema‐
       turely if the EOF is reached:

       > 2:ino,*?d

       Example 9: Displaying Changes to the Current Inode

       The  following command displays changes the current inode to that asso‐
       ciated with the 5th directory entry (numbered from zero) of the current
       inode. The first logical block of the file is then displayed in ASCII:

       > 5:dir:inode; 0:file,*/c

       Example 10: Displaying the Superblock

       The following command displays the superblock of this file system:

       > :sb

       Example 11: Displaying the Cylinder Group

       The  following  command displays cylinder group information and summary
       for cylinder group 1:

       > 1:cg?c

       Example 12: Changing the i-number

       The following command changes the i-number for  the  seventh  directory
       slot in the root directory to 3:

       > 2:inode; 7:dir=3

       Example 13: Displaying as Directory Entries

       The  following command displays the third block of the current inode as
       directory entries:

       > 2:db:block,*?d

       Example 14: Changing the Name Field

       The following command changes the name field in the directory  slot  to
       name:

       > 7:dir:nm="name"

       Example 15: Getting and Filling Elements

       The  following command gets fragment 3c3 and fill 20 type elements with
       0x20:

       > 3c3:fragment,20:fill=0x20

       Example 16: Setting the Contents of an Address

       The following command sets the contents of address 2050 to  0xffffffff.
       0xffffffff may be truncated depending on the current type:

       > 2050=0xffff

       Example 17: Placing ASCII

       The following command places the ASCII for the string at 1c92434:

       > 1c92434="this is some text"

       Example 18: Displaying Shadow Inode Data

       The  following  command	displays  all  of the shadow inode data in the
       shadow inode associated with the root inode of this file system:

       > 2:ino:si:ino;0:shadow,*?S

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       ┌─────────────────────────────┬─────────────────────────────┐
       │      ATTRIBUTE TYPE	     │	    ATTRIBUTE VALUE	   │
       ├─────────────────────────────┼─────────────────────────────┤
       │Availability		     │SUNWcsu			   │
       └─────────────────────────────┴─────────────────────────────┘

SEE ALSO
       clri(1M), fsck_ufs(1M), dir_ufs(4), attributes(5), ufs(7FS)

WARNINGS
       Since fsdb reads the disk raw, extreme caution is advised in  determin‐
       ing  its	 availability of fsdb on the system. Suggested permissions are
       600 and owned by bin.

NOTES
       The old command line syntax for clearing i-nodes using the ufs-specific
       '-z  i-number' option is still supported by the new debugger, though it
       is obsolete and will be removed in a future release. Use of  this  flag
       will  result in correct operation, but an error message will be printed
       warning of the impending obsolesence of this option to the command. The
       equivalent  functionality is available using the more flexible clri(1M)
       command.

SunOS 5.10			  14 Apr 2003			  fsdb_ufs(1M)
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