1fsdb_udfs(1M) System Administration Commands fsdb_udfs(1M)
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6 fsdb_udfs - udfs file system debugger
7
9 fsdb [-F] udfs [generic_option] [-o specific_option] special
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13 The fsdb_udfs command is an interactive tool that can be used to patch
14 up a damaged udfs file system. fsdb_udfs has conversions to translate
15 block and i-numbers into their corresponding disk addresses. Mnemonic
16 offsets to access different parts of an inode are also included.
17 Mnemonic offsets greatly simplify the process of correcting control
18 block entries or descending the file system tree.
19 fsdb contains several error-checking routines to verify inode and block
22 addresses. These can be disabled if necessary by invoking fsdb with the
23 -o option or by using the o command.
24 fsdb reads one block at a time, and therefore works with raw as well as
27 block I/O devices. A buffer management routine is used to retain com‐
28 monly used blocks of data in order to reduce the number of read system
29 calls. All assignment operations result in an immediate write-through
30 of the corresponding block. In order to modify any portion of the disk,
31 fsdb must be invoked with the -w option.
32 Wherever possible, adb-like syntax has been adopted to promote the use
35 of fsdb through familiarity.
36
38 The following options are supported:
39 -o specific_option Specify udfs file system specific options in a
41 comma-separated list with no intervening spaces.
42 The following specific options are supported:
43 o Override some error conditions.
45 p=string Set prompt to string.
48 w Open for write.
51 ? Display usage.
54
58 Numbers are considered hexadecimal by default. The user has control
59 over how data is to be displayed or accepted. The base command displays
60 or sets the input and output base. Once set, all input defaults to this
61 base and all output displays in this base. The base can be overriden
62 temporarily for input by preceding hexadecimal numbers by 0x, preceding
63 decimal numbers with a 0t, or octal numbers with a 0. Hexadecimal num‐
64 bers beginning with a-f or A -F must be preceded with a 0x to distin‐
65 guish them from commands.
66 Disk addressing by fsdb is at the byte level. However, fsdb offers many
69 commands to convert a desired inode, directory entry, block, and so
70 forth, to a byte address. After the address has been calculated, fsdb
71 records the result in the current address (dot).
72 Several global values are maintained by fsdb:
75 o Current base (referred to as base)
77 o Current address (referred to as dot)
79 o Current inode (referred to as inode)
81 o Current count (referred to as count)
83 o Current type (referred to as type)
85 Most commands use the preset value of dot in their execution. For exam‐
88 ple,
89 > 2:inode
91 first sets the value of dot (.) to 2, colon (:), signifies the start of
96 a command, and the inode command sets inode to 2. A count is specified
97 after a comma (,). Once set, count remains at this value until a new
98 command is encountered that resets the value back to 1 (the default).
99 So, if
102 > 2000,400/X
104 is entered, 400 hex longs are listed from 2000, and when completed, the
109 value of dot is 2000 + 400 * sizeof (long). If a RETURN is then
110 entered, the output routine uses the current values of dot, count, and
111 type and displays 400 more hex longs. An asterisk (*) causes the entire
112 block to be displayed. An example showing several commands and the use
113 of RETURN would be:
114 > 2:ino; 0:dir?d
116 or
121 > 2:ino; 0:db:block?d
123 The two examples are synonymous for getting to the first directory
128 entry of the root of the file system. Once there, subsequently entering
129 a RETURN, plus (+), or minus (-) advances to subsequent entries.
130 Notice that
131 > 2:inode; :ls
133 or
138 > :ls /
140 is again synonymous.
145 Expressions
147 The following symbols are recognized by fsdb:
148 RETURN Update the value of dot by the current value of type and
150 display using the current value of count.
151 # Update the value of dot by specifying a numeric expres‐
154 sion. Specify numeric expressions using addition, subtrac‐
155 tion, mulitiplication, and division operators ( +, -, *,
156 and %). Numeric expressions are evaluated from left to
157 right and can use parentheses. After evaluation, the value
158 of dot is updated.
159 , count Update the count indicator. The global value of count is
162 updated to count. The value of count remains until a new
163 command is run. A count specifier of * attempts to show a
164 blocks's worth of information. The default for count is 1.
165 ? f Display in structured style with format specifier f. See
168 Formatted Output.
169 / f Display in unstructured style with format specifier f. See
172 Formatted Output.
173 . Display the value of dot.
176 +e Increment the value of dot by the expression e. The amount
179 actually incremented is dependent on the size of type: dot
180 = dot + e * sizeof (type) The default for e is 1.
181 −e Decrement the value of dot by the expression e . See +.
184 *e Multiply the value of dot by the expression e. Multiplica‐
187 tion and division don't use type. In the above calculation
188 of dot, consider the sizeof (type) to be 1.
189 %e Divide the value of dot by the expression e. See *.
192 < name Restore an address saved in register name. name must be a
195 single letter or digit.
196 > name Save an address in register name. name must be a single
199 letter or digit.
200 = f Display indicator. If f is a legitimate format specifier
203 (see Formatted Output), then the value of dot is displayed
204 using format specifier f. Otherwise, assignment is
205 assumed. See = [s] [e].
206 = [s] [e] Change the value of dot using an assignment indicator. The
209 address pointed to by dot has its contents changed to the
210 value of the expression e or to the ASCII representation
211 of the quoted (") string s. This can be useful for chang‐
212 ing directory names or ASCII file information.
213 =+ e Change the value of dot using an incremental assignment.
216 The address pointed to by dot has its contents incremented
217 by expression e.
218 =- e Change the value of dot using a decremental assignment.
221 Decrement the contents of the address pointed to by dot by
222 expression e.
223 Commands
226 A command must be prefixed by a colon (:). Only enough letters of the
227 command to uniquely distinguish it are needed. Multiple commands can be
228 entered on one line by separating them by a SPACE, TAB, or semicolon
229 (;).
230 To view a potentially unmounted disk in a reasonable manner, fsdb sup‐
233 ports the cd, pwd, ls, and find commands. The functionality of each of
234 these commands basically matches that of its UNIX counterpart. See
235 cd(1), pwd(1),ls(1), andfind(1) for details. The *, ,, ?, and - wild‐
236 card characters are also supported.
237 The following commands are supported:
240 base[=b]
242 Display or set the base. All input and output is governed by the
244 current base. Without the = b, displays the current base. Other‐
245 wise, sets the current base to b. Base is interpreted using the old
246 value of base, so to ensure correctness use the 0, 0t, or 0x prefix
247 when changing the base. The default for base is hexadecimal.
248 block
251 Convert the value of dot to a block address.
253 cd [dir]
256 Change the current directory to directory dir. The current values
258 of inode and dot are also updated. If dir is not specified, changes
259 directories to inode 2, root (/).
260 directory
263 If the current inode is a directory, converts the value of dot to a
265 directory slot offset in that directory, and dot now points to this
266 entry.
267 file
270 Set the value of dot as a relative block count from the beginning
272 of the file. The value of dot is updated to the first byte of this
273 block.
274 find dir [-name n] | [-inum i]
277 Find files by name or i-number. Recursively searches directory dir
279 and below for file names whose i-number matches i or whose name
280 matches pattern n. Only one of the two options (-name or -inum) can
281 be used at one time. The find -print is not necessary or accepted.
282 fill=p
285 Fill an area of disk with pattern p. The area of disk is delimited
287 by dot and count.
288 inode
291 Convert the value of dot to an inode address. If successful, the
293 current value of inode is updated as well as the value of dot. As a
294 convenient shorthand, if :inode appears at the beginning of the
295 line, the value of dot is set to the current inode and that inode
296 is displayed in inode format.
297 ls [ -R ] [-l ] pat1 pat2...
300 List directories or files. If no file is specified, the current
302 directory is assumed. Either or both of the options can be used
303 (but, if used, must be specified before the filename specifiers).
304 Wild card characters are available and multiple arguments are
305 acceptable. The long listing shows only the i-number and the name;
306 use the inode command with ?i to get more information.
307 override
310 Toggle the value of override. Some error conditions might be over‐
312 ridden if override is toggled to on.
313 prompt "p"
316 Change the fsdb prompt to p. p must be enclosed in quotes.
318 pwd
321 Display the current working directory.
323 quit
326 Quit fsdb.
328 tag
331 Convert the value of dot and if this is a valid tag, print the vol‐
333 ume structure according to the tag.
334 !
337 Escape to the shell.
339 Inode Commands
342 In addition to the above commands, several other commands deal with
343 inode fields and operate directly on the current inode (they still
344 require the colon (:). They can be used to more easily display or
345 change the particular fields. The value of dot is only used by the :db
346 and :ib commands. Upon completion of the command, the value of dot is
347 changed so that it points to that particular field. For example,
348 > :ln=+1
350 increments the link count of the current inode and sets the value of
355 dot to the address of the link count field.
356 The following inode commands are supported:
359 at Access time
361 bs Block size
364 ct Creation time
367 gid Group id
370 ln Link number
373 mt Modification time
376 md Mode
379 maj Major device number
382 min Minor device number
385 nm This command actually operates on the directory name field.
388 Once poised at the desired directory entry (using the
389 directory command), this command allows you to change or dis‐
390 play the directory name. For example,
391 > 7:dir:nm="foo"
393 gets the 7th directory entry of the current inode and changes
396 its name to foo. Directory names cannot be made larger than the
397 field allows. If an attempt is made to make a directory name
398 larger than the field allows,, the string is truncated to fit
399 and a warning message is displayed.
400 sz File size
403 uid User ID
406 uniq Unique ID
409 Formatted Output
412 Formatted output comes in two styles and many format types. The two
413 styles of formatted output are: structured and unstructured. Structured
414 output is used to display inodes, directories, and so forth. Unstruc‐
415 tured output displays raw data.
416 Format specifiers are preceded by the slash (/) or question mark (?)
419 character. type is updated as necessary upon completion.
420 The following format specifiers are preceded by the ? character:
423 i Display as inodes in the current base.
425 d Display as directories in the current base.
428 The following format specifiers are preceded by the / character:
432 b Display as bytes in the current base.
434 c Display as characters.
437 o | O Display as octal shorts or longs.
440 d | D Display as decimal shorts or longs.
443 x | X Display as hexadecimal shorts or longs.
446
449 Example 1 Using fsdb as a calculator for complex arithmetic
450 The following command displays 2010 in decimal format, and is an exam‐
453 ple of using fsdb as a calculator for complex arithmetic.
454 > 2000+400%(20+20)=D
457 Example 2 Using fsdb to display an i-number in idode fomat
461 The following command displays the i-number 386 in inode format.386
464 becomes the current inode.
465 > 386:ino?i
468 Example 3 Using fsdb to change the link count
472 The following command changes the link count for the current inode to
475 4.
476 > :ln=4
479 Example 4 Using fsdb to increment the link count
483 The following command increments the link count by 1.
486 > :ln=+1
489 Example 5 Using fsdb to display the creation time as a hexadecimal long
493 The following command displays the creation time as a hexadecimal long.
496 > :ct=X
499 Example 6 Using fsdb to display the modification time in time format
503 The following command displays the modification time in time format.
506 > :mt=t
509 Example 7 Using fsdb to display in ASCII
513 The following command displays, in ASCII, block 0 of the file associ‐
516 ated with the current inode.
517 > 0:file/c
520 Example 8 Using fsdb to display the directory enteries for the root
524 inode
525 The following command displays the first block's directory entries for
528 the root inode of this file system. This command stops prematurely if
529 the EOF is reached.
530 > 2:ino,*?d
533 Example 9 Using fsdb to change the current inode
537 The following command changes the current inode to that associated
540 with the 5th directory entry (numbered from 0) of the current inode.
541 The first logical block of the file is then displayed in ASCII.
542 > 5:dir:inode; 0:file,*/c
545 Example 10 Using fsdb to change the i-number
549 The following command changes the i-number for the 7th directory slot
552 in the root directory to 3.
553 > 2:inode; 7:dir=3
556 Example 11 Using fsdb to change the name field
560 The following command changes the name field in the directory slot to
563 name.
564 > 7:dir:nm="name"
567 Example 12 Using fsdb to display the a block
571 The following command displays the 3rd block of the current inode as
574 directory entries.
575 Example 13 Using fsdb to set the contents of address
578 The following command sets the contents of address 2050 to 0xffffffff.
581 0xffffffff can be truncated, depending on the current type.
582 > 2050=0xffff
585 Example 14 Using fsdb to place an ASCII string at an address
589 The following command places the ASCII string this is some text at
592 address 1c92434.
593 > 1c92434="this is some text"
596
600 See attributes(5) for descriptions of the following attributes:
601 ┌─────────────────────────────┬─────────────────────────────┐
606 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
607 ├─────────────────────────────┼─────────────────────────────┤
608 │Availability │SUNWudf │
609 └─────────────────────────────┴─────────────────────────────┘
610
612 clri(1M), fsck_udfs(1M), dir(4), attributes(5)
613SunOS 5.11 11 Jun 1999 fsdb_udfs(1M)