3 6e18e03e 2004-04-11 devnull db \- debugger
4 6e18e03e 2004-04-11 devnull .SH SYNOPSIS
7 6e18e03e 2004-04-11 devnull .I option ...
10 6e18e03e 2004-04-11 devnull .I textfile
15 6e18e03e 2004-04-11 devnull .I corefile
17 6e18e03e 2004-04-11 devnull .SH DESCRIPTION
19 6e18e03e 2004-04-11 devnull is a general purpose debugging program.
20 6e18e03e 2004-04-11 devnull It may be used to examine files and to provide
21 6e18e03e 2004-04-11 devnull a controlled environment for the execution
22 6e18e03e 2004-04-11 devnull of programs.
25 6e18e03e 2004-04-11 devnull .I textfile
26 6e18e03e 2004-04-11 devnull is a file containing the text and initialized
27 6e18e03e 2004-04-11 devnull data of an executable program.
31 6e18e03e 2004-04-11 devnull .I corefile
32 6e18e03e 2004-04-11 devnull specifies the memory image of a process.
35 6e18e03e 2004-04-11 devnull gives the id of an executing process to be accessed via
36 058b0118 2005-01-03 devnull .IR ptrace (2).
38 6e18e03e 2004-04-11 devnull .I corefile
39 6e18e03e 2004-04-11 devnull specifies the name of a core dump (see
40 6e18e03e 2004-04-11 devnull .IR core (5)
41 6e18e03e 2004-04-11 devnull on your system of choice) containing the
42 6e18e03e 2004-04-11 devnull memory image of a terminated process.
43 6e18e03e 2004-04-11 devnull This manual refers to the memory image specified by
46 6e18e03e 2004-04-11 devnull .I corefile
48 6e18e03e 2004-04-11 devnull .IR memfile .
52 6e18e03e 2004-04-11 devnull associated with each
53 6e18e03e 2004-04-11 devnull .I textfile
55 6e18e03e 2004-04-11 devnull .I memfile
56 6e18e03e 2004-04-11 devnull supports accesses to instructions and data in the file;
57 6e18e03e 2004-04-11 devnull see `Addresses'.
59 6e18e03e 2004-04-11 devnull An argument consisting entirely of digits is assumed
60 6e18e03e 2004-04-11 devnull to be a process id; otherwise, it is the name of a
61 6e18e03e 2004-04-11 devnull .I textfile
63 6e18e03e 2004-04-11 devnull .IR corefile .
65 6e18e03e 2004-04-11 devnull .I textfile
66 6e18e03e 2004-04-11 devnull is given, the textfile map
67 6e18e03e 2004-04-11 devnull is associated with it.
68 6e18e03e 2004-04-11 devnull If only a
69 6e18e03e 2004-04-11 devnull .I memfile
70 6e18e03e 2004-04-11 devnull is given, the textfile map is
71 6e18e03e 2004-04-11 devnull derived from the corresponding
72 6e18e03e 2004-04-11 devnull .IR textfile ,
73 6e18e03e 2004-04-11 devnull if it can be determined
74 6e18e03e 2004-04-11 devnull (this varies from system to system).
76 6e18e03e 2004-04-11 devnull .I memfile
77 6e18e03e 2004-04-11 devnull is given, the memfile map is associated with it;
78 6e18e03e 2004-04-11 devnull otherwise the map is undefined and accesses to it
79 6e18e03e 2004-04-11 devnull are not permitted.
81 6e18e03e 2004-04-11 devnull Commands to
83 6e18e03e 2004-04-11 devnull are read from the standard input and
84 6e18e03e 2004-04-11 devnull responses are to the standard output.
85 6e18e03e 2004-04-11 devnull The options are
89 6e18e03e 2004-04-11 devnull .I textfile
91 6e18e03e 2004-04-11 devnull .I memfile
92 6e18e03e 2004-04-11 devnull for writing as well as reading.
94 6e18e03e 2004-04-11 devnull .BI -I path
95 6e18e03e 2004-04-11 devnull Directory in which to look for relative path names in
99 6e18e03e 2004-04-11 devnull commands.
101 6e18e03e 2004-04-11 devnull .BI -m machine
102 6e18e03e 2004-04-11 devnull Assume instructions are for the given CPU type
103 6e18e03e 2004-04-11 devnull (possible names include
106 6e18e03e 2004-04-11 devnull .BR powerpc ;
108 6e18e03e 2004-04-11 devnull the suffix
111 6e18e03e 2004-04-11 devnull .B 386-co
113 6e18e03e 2004-04-11 devnull .B powerpc-co
114 6e18e03e 2004-04-11 devnull selects disassembly in the manufacturer's syntax, if
115 6e18e03e 2004-04-11 devnull available,
116 6e18e03e 2004-04-11 devnull rather than the default Plan 9 syntax).
120 6e18e03e 2004-04-11 devnull commands have the following form:
122 6e18e03e 2004-04-11 devnull .RI [ address ]
124 6e18e03e 2004-04-11 devnull .IR count ]
125 6e18e03e 2004-04-11 devnull .RI [ command ]
128 6e18e03e 2004-04-11 devnull .I address
129 6e18e03e 2004-04-11 devnull is present then the current position, called `dot',
130 6e18e03e 2004-04-11 devnull is set to
131 6e18e03e 2004-04-11 devnull .IR address .
132 6e18e03e 2004-04-11 devnull Initially dot
133 6e18e03e 2004-04-11 devnull is set to 0.
134 6e18e03e 2004-04-11 devnull Most commands are repeated
135 6e18e03e 2004-04-11 devnull .I count
136 6e18e03e 2004-04-11 devnull times with
137 6e18e03e 2004-04-11 devnull dot advancing between repetitions.
138 6e18e03e 2004-04-11 devnull The default
139 6e18e03e 2004-04-11 devnull .I count
141 6e18e03e 2004-04-11 devnull .I Address
143 6e18e03e 2004-04-11 devnull .I count
144 6e18e03e 2004-04-11 devnull are expressions.
145 6e18e03e 2004-04-11 devnull Multiple commands on one line must be separated by
147 6e18e03e 2004-04-11 devnull .SS Expressions
148 6e18e03e 2004-04-11 devnull Expressions are evaluated as long
149 6e18e03e 2004-04-11 devnull .IR ints .
150 6e18e03e 2004-04-11 devnull .TP 7.2n
152 6e18e03e 2004-04-11 devnull The value of dot.
153 6e18e03e 2004-04-11 devnull .TP 7.2n
155 6e18e03e 2004-04-11 devnull The value of dot
156 6e18e03e 2004-04-11 devnull incremented by the current increment.
157 6e18e03e 2004-04-11 devnull .TP 7.2n
159 6e18e03e 2004-04-11 devnull The value of dot
160 6e18e03e 2004-04-11 devnull decremented by the current increment.
161 6e18e03e 2004-04-11 devnull .TP 7.2n
163 6e18e03e 2004-04-11 devnull The last
164 6e18e03e 2004-04-11 devnull .I address
166 6e18e03e 2004-04-11 devnull .TP 7.2n
167 6e18e03e 2004-04-11 devnull .I integer
168 6e18e03e 2004-04-11 devnull A number, in decimal radix by default.
169 6e18e03e 2004-04-11 devnull The prefixes
175 6e18e03e 2004-04-11 devnull (zero oh) force interpretation
176 6e18e03e 2004-04-11 devnull in octal radix; the prefixes
180 6e18e03e 2004-04-11 devnull force interpretation in
181 6e18e03e 2004-04-11 devnull decimal radix; the prefixes
182 6e18e03e 2004-04-11 devnull .LR 0x ,
183 6e18e03e 2004-04-11 devnull .LR 0X ,
186 6e18e03e 2004-04-11 devnull force interpretation in
187 6e18e03e 2004-04-11 devnull hexadecimal radix.
189 6e18e03e 2004-04-11 devnull .LR 020 ,
190 6e18e03e 2004-04-11 devnull .LR 0o20 ,
191 6e18e03e 2004-04-11 devnull .LR 0t16 ,
194 6e18e03e 2004-04-11 devnull all represent sixteen.
195 6e18e03e 2004-04-11 devnull .TP 7.2n
196 6e18e03e 2004-04-11 devnull .IB integer . fraction
197 6e18e03e 2004-04-11 devnull A single-precision floating point number.
198 6e18e03e 2004-04-11 devnull .TP 7.2n
199 6e18e03e 2004-04-11 devnull .BI \' c\| \'
202 6e18e03e 2004-04-11 devnull value of a character.
204 6e18e03e 2004-04-11 devnull may be used to escape a
205 6e18e03e 2004-04-11 devnull .LR \' .
206 6e18e03e 2004-04-11 devnull .TP 7.2n
207 6e18e03e 2004-04-11 devnull .BI < name
208 6e18e03e 2004-04-11 devnull The value of
209 6e18e03e 2004-04-11 devnull .IR name ,
210 6e18e03e 2004-04-11 devnull which is a register name.
211 6e18e03e 2004-04-11 devnull The register names are
212 6e18e03e 2004-04-11 devnull those printed by the
214 6e18e03e 2004-04-11 devnull command.
215 6e18e03e 2004-04-11 devnull .TP 7.2n
216 6e18e03e 2004-04-11 devnull .I symbol
218 6e18e03e 2004-04-11 devnull .I symbol
219 6e18e03e 2004-04-11 devnull is a sequence
220 6e18e03e 2004-04-11 devnull of upper or lower case letters, underscores or
221 6e18e03e 2004-04-11 devnull digits, not starting with a digit.
223 6e18e03e 2004-04-11 devnull may be used to escape other characters.
224 6e18e03e 2004-04-11 devnull The location of the
225 6e18e03e 2004-04-11 devnull .I symbol
226 6e18e03e 2004-04-11 devnull is calculated from the symbol table
228 6e18e03e 2004-04-11 devnull .IR textfile .
229 6e18e03e 2004-04-11 devnull .TP 7.2n
230 6e18e03e 2004-04-11 devnull .IB routine . name
231 6e18e03e 2004-04-11 devnull The address of the variable
233 6e18e03e 2004-04-11 devnull in the specified
234 6e18e03e 2004-04-11 devnull C routine.
236 6e18e03e 2004-04-11 devnull .I routine
240 6e18e03e 2004-04-11 devnull .IR symbols .
243 6e18e03e 2004-04-11 devnull is omitted the value is the address of the
244 6e18e03e 2004-04-11 devnull most recently activated stack frame
245 6e18e03e 2004-04-11 devnull corresponding to
246 6e18e03e 2004-04-11 devnull .IR routine ;
248 6e18e03e 2004-04-11 devnull .I routine
249 6e18e03e 2004-04-11 devnull is omitted,
250 6e18e03e 2004-04-11 devnull the active procedure
251 6e18e03e 2004-04-11 devnull is assumed.
252 6e18e03e 2004-04-11 devnull .TP 7.2n
253 6e18e03e 2004-04-11 devnull .IB file : integer
254 6e18e03e 2004-04-11 devnull The address of the instruction corresponding
255 6e18e03e 2004-04-11 devnull to the source statement at the indicated
256 6e18e03e 2004-04-11 devnull line number of the file. If the source line contains
257 6e18e03e 2004-04-11 devnull no executable statement, the address of the
258 6e18e03e 2004-04-11 devnull instruction associated with the nearest
259 6e18e03e 2004-04-11 devnull executable source line is returned. Files
260 6e18e03e 2004-04-11 devnull begin at line 1. If multiple files of the same
261 6e18e03e 2004-04-11 devnull name are loaded, an expression of this form resolves
262 6e18e03e 2004-04-11 devnull to the first file encountered in the symbol table.
263 6e18e03e 2004-04-11 devnull .TP 7.2n
264 6e18e03e 2004-04-11 devnull .BI ( exp )
265 6e18e03e 2004-04-11 devnull The value of the expression
266 6e18e03e 2004-04-11 devnull .IR exp .
268 6e18e03e 2004-04-11 devnull .I Monadic operators
270 6e18e03e 2004-04-11 devnull .TP 7.2n
271 6e18e03e 2004-04-11 devnull .BI * exp
272 6e18e03e 2004-04-11 devnull The contents of the location addressed
276 6e18e03e 2004-04-11 devnull .IR memfile .
277 6e18e03e 2004-04-11 devnull .TP 7.2n
278 6e18e03e 2004-04-11 devnull .BI @ exp
279 6e18e03e 2004-04-11 devnull The contents of the location addressed by
282 6e18e03e 2004-04-11 devnull .IR textfile .
283 6e18e03e 2004-04-11 devnull .TP 7.2n
284 6e18e03e 2004-04-11 devnull .BI - exp
285 6e18e03e 2004-04-11 devnull Integer negation.
286 6e18e03e 2004-04-11 devnull .TP 7.2n
287 6e18e03e 2004-04-11 devnull .BI ~ exp
288 6e18e03e 2004-04-11 devnull Bitwise complement.
289 6e18e03e 2004-04-11 devnull .TP 7.2n
290 6e18e03e 2004-04-11 devnull .BI % exp
291 6e18e03e 2004-04-11 devnull When used as an
292 6e18e03e 2004-04-11 devnull .IR address ,
294 6e18e03e 2004-04-11 devnull is an offset into the segment named
295 6e18e03e 2004-04-11 devnull .IR ublock ;
296 6e18e03e 2004-04-11 devnull see `Addresses'.
299 6e18e03e 2004-04-11 devnull .I "Dyadic\ operators"
300 6e18e03e 2004-04-11 devnull are left-associative
301 6e18e03e 2004-04-11 devnull and are less binding than monadic operators.
303 6e18e03e 2004-04-11 devnull .TP 7.2n
304 6e18e03e 2004-04-11 devnull .IB e1 + e2
305 6e18e03e 2004-04-11 devnull Integer addition.
306 6e18e03e 2004-04-11 devnull .TP 7.2n
307 6e18e03e 2004-04-11 devnull .IB e1 - e2
308 6e18e03e 2004-04-11 devnull Integer subtraction.
309 6e18e03e 2004-04-11 devnull .TP 7.2n
310 6e18e03e 2004-04-11 devnull .IB e1 * e2
311 6e18e03e 2004-04-11 devnull Integer multiplication.
312 6e18e03e 2004-04-11 devnull .TP 7.2n
313 6e18e03e 2004-04-11 devnull .IB e1 % e2
314 6e18e03e 2004-04-11 devnull Integer division.
315 6e18e03e 2004-04-11 devnull .TP 7.2n
316 6e18e03e 2004-04-11 devnull .IB e1 & e2
317 6e18e03e 2004-04-11 devnull Bitwise conjunction.
318 6e18e03e 2004-04-11 devnull .TP 7.2n
319 6e18e03e 2004-04-11 devnull .IB e1 | e2
320 6e18e03e 2004-04-11 devnull Bitwise disjunction.
321 6e18e03e 2004-04-11 devnull .TP 7.2n
322 6e18e03e 2004-04-11 devnull .IB e1 # e2
324 6e18e03e 2004-04-11 devnull rounded up to the next multiple of
325 6e18e03e 2004-04-11 devnull .IR e2 .
328 6e18e03e 2004-04-11 devnull .SS Commands
329 6e18e03e 2004-04-11 devnull Most commands have the following syntax:
332 6e18e03e 2004-04-11 devnull Locations starting at
333 6e18e03e 2004-04-11 devnull .I address
335 6e18e03e 2004-04-11 devnull .I textfile
336 6e18e03e 2004-04-11 devnull are printed according to the format
340 6e18e03e 2004-04-11 devnull Locations starting at
341 6e18e03e 2004-04-11 devnull .I address
343 6e18e03e 2004-04-11 devnull .I memfile
344 6e18e03e 2004-04-11 devnull are printed according to the format
348 6e18e03e 2004-04-11 devnull The value of
349 6e18e03e 2004-04-11 devnull .I address
350 6e18e03e 2004-04-11 devnull itself is printed according to the format
354 6e18e03e 2004-04-11 devnull .I format
355 6e18e03e 2004-04-11 devnull consists of one or more characters that specify a style
356 6e18e03e 2004-04-11 devnull of printing.
357 6e18e03e 2004-04-11 devnull Each format character may be preceded by a decimal integer
358 6e18e03e 2004-04-11 devnull that is a repeat count for the format character.
359 6e18e03e 2004-04-11 devnull If no format is given then the last format is used.
361 6e18e03e 2004-04-11 devnull Most format letters fetch some data,
362 6e18e03e 2004-04-11 devnull print it,
363 6e18e03e 2004-04-11 devnull and advance (a local copy of) dot
364 6e18e03e 2004-04-11 devnull by the number of bytes fetched.
365 6e18e03e 2004-04-11 devnull The total number of bytes in a format becomes the
366 6e18e03e 2004-04-11 devnull .IR current increment .
367 6e18e03e 2004-04-11 devnull .ta 2.5n .5i
372 6e18e03e 2004-04-11 devnull Print two-byte integer in octal.
375 6e18e03e 2004-04-11 devnull Print four-byte integer in octal.
378 6e18e03e 2004-04-11 devnull Print two-byte integer in signed octal.
381 6e18e03e 2004-04-11 devnull Print four-byte integer in signed octal.
384 6e18e03e 2004-04-11 devnull Print two-byte integer in decimal.
387 6e18e03e 2004-04-11 devnull Print four-byte integer in decimal.
390 6e18e03e 2004-04-11 devnull Print eight-byte integer in decimal.
393 6e18e03e 2004-04-11 devnull Print eight-byte integer in unsigned decimal.
396 6e18e03e 2004-04-11 devnull Print two-byte integer in hexadecimal.
399 6e18e03e 2004-04-11 devnull Print four-byte integer in hexadecimal.
402 6e18e03e 2004-04-11 devnull Print eight-byte integer in hexadecimal.
405 6e18e03e 2004-04-11 devnull Print two-byte integer in unsigned decimal.
408 6e18e03e 2004-04-11 devnull Print four-byte integer in unsigned decimal.
412 6e18e03e 2004-04-11 devnull as a single-precision floating point number.
415 6e18e03e 2004-04-11 devnull Print double-precision floating point.
418 6e18e03e 2004-04-11 devnull Print the addressed byte in hexadecimal.
421 6e18e03e 2004-04-11 devnull Print the addressed byte as an
422 6e18e03e 2004-04-11 devnull .SM ASCII
423 6e18e03e 2004-04-11 devnull character.
426 6e18e03e 2004-04-11 devnull Print the addressed byte as a character.
427 6e18e03e 2004-04-11 devnull Printable
428 6e18e03e 2004-04-11 devnull .SM ASCII
429 6e18e03e 2004-04-11 devnull characters
430 6e18e03e 2004-04-11 devnull are represented normally; others
431 6e18e03e 2004-04-11 devnull are printed in the form
432 6e18e03e 2004-04-11 devnull .BR \exnn .
435 6e18e03e 2004-04-11 devnull Print the addressed characters, as a
437 6e18e03e 2004-04-11 devnull string, until a zero byte
438 6e18e03e 2004-04-11 devnull is reached.
439 6e18e03e 2004-04-11 devnull Advance dot
440 6e18e03e 2004-04-11 devnull by the length of the string,
441 6e18e03e 2004-04-11 devnull including the zero terminator.
444 6e18e03e 2004-04-11 devnull Print a string using
445 6e18e03e 2004-04-11 devnull the escape convention (see
450 6e18e03e 2004-04-11 devnull Print as
452 6e18e03e 2004-04-11 devnull the addressed two-byte integer (rune).
455 6e18e03e 2004-04-11 devnull Print as
457 6e18e03e 2004-04-11 devnull the addressed two-byte integers as runes
458 6e18e03e 2004-04-11 devnull until a zero rune is reached.
459 6e18e03e 2004-04-11 devnull Advance dot
460 6e18e03e 2004-04-11 devnull by the length of the string,
461 6e18e03e 2004-04-11 devnull including the zero terminator.
464 6e18e03e 2004-04-11 devnull Print as machine instructions. Dot is
465 6e18e03e 2004-04-11 devnull incremented by the size of the instruction.
470 6e18e03e 2004-04-11 devnull above, but print the machine instructions in
471 6e18e03e 2004-04-11 devnull an alternate form if possible.
474 6e18e03e 2004-04-11 devnull Print the addressed machine instruction in a
475 6e18e03e 2004-04-11 devnull machine-dependent hexadecimal form.
478 6e18e03e 2004-04-11 devnull Print the value of dot
479 6e18e03e 2004-04-11 devnull in symbolic form.
480 6e18e03e 2004-04-11 devnull Dot is unaffected.
483 6e18e03e 2004-04-11 devnull Print the value of dot
484 6e18e03e 2004-04-11 devnull in hexadecimal.
485 6e18e03e 2004-04-11 devnull Dot is unaffected.
488 6e18e03e 2004-04-11 devnull Print the function name, source file, and line number
489 6e18e03e 2004-04-11 devnull corresponding to dot (textfile only). Dot is unaffected.
492 6e18e03e 2004-04-11 devnull Print the addressed value in symbolic form.
493 6e18e03e 2004-04-11 devnull Dot is advanced by the size of a machine address.
496 6e18e03e 2004-04-11 devnull When preceded by an integer, tabs to the next
497 6e18e03e 2004-04-11 devnull appropriate tab stop.
498 6e18e03e 2004-04-11 devnull For example,
500 6e18e03e 2004-04-11 devnull moves to the next 8-space tab stop.
501 6e18e03e 2004-04-11 devnull Dot is unaffected.
504 6e18e03e 2004-04-11 devnull Print a newline.
505 6e18e03e 2004-04-11 devnull Dot is unaffected.
508 6e18e03e 2004-04-11 devnull .BR ' ... '
509 6e18e03e 2004-04-11 devnull Print the enclosed string.
510 6e18e03e 2004-04-11 devnull Dot is unaffected.
515 6e18e03e 2004-04-11 devnull Dot is decremented by the current increment.
516 6e18e03e 2004-04-11 devnull Nothing is printed.
519 6e18e03e 2004-04-11 devnull Dot is incremented by 1.
520 6e18e03e 2004-04-11 devnull Nothing is printed.
523 6e18e03e 2004-04-11 devnull Dot is decremented by 1.
524 6e18e03e 2004-04-11 devnull Nothing is printed.
528 6e18e03e 2004-04-11 devnull Other commands include:
531 6e18e03e 2004-04-11 devnull Update dot by the current increment.
532 6e18e03e 2004-04-11 devnull Repeat the previous command with a
533 6e18e03e 2004-04-11 devnull .I count
536 6e18e03e 2004-04-11 devnull .RB [ ?/ ] l "\fI value mask\fR"
537 6e18e03e 2004-04-11 devnull Words starting at dot
538 6e18e03e 2004-04-11 devnull are masked with
540 6e18e03e 2004-04-11 devnull and compared with
541 6e18e03e 2004-04-11 devnull .I value
543 6e18e03e 2004-04-11 devnull a match is found.
546 6e18e03e 2004-04-11 devnull is used,
547 6e18e03e 2004-04-11 devnull the match is for a two-byte integer;
549 6e18e03e 2004-04-11 devnull matches four bytes.
550 6e18e03e 2004-04-11 devnull If no match is found then dot
551 6e18e03e 2004-04-11 devnull is unchanged; otherwise dot
552 6e18e03e 2004-04-11 devnull is set to the matched location.
555 6e18e03e 2004-04-11 devnull is omitted then ~0 is used.
557 6e18e03e 2004-04-11 devnull .RB [ ?/ ] w "\fI value ...\fR"
558 6e18e03e 2004-04-11 devnull Write the two-byte
559 6e18e03e 2004-04-11 devnull .I value
560 6e18e03e 2004-04-11 devnull into the addressed
561 6e18e03e 2004-04-11 devnull location.
562 6e18e03e 2004-04-11 devnull If the command is
564 6e18e03e 2004-04-11 devnull write four bytes.
566 6e18e03e 2004-04-11 devnull .RB [ ?/ ] "m\fI s b e f \fP" [ ?\fR]
568 6e18e03e 2004-04-11 devnull New values for
569 6e18e03e 2004-04-11 devnull .RI ( b,\ e,\ f )
570 6e18e03e 2004-04-11 devnull in the segment named
572 6e18e03e 2004-04-11 devnull are recorded. Valid segment names are
573 6e18e03e 2004-04-11 devnull .IR text ,
574 6e18e03e 2004-04-11 devnull .IR data ,
576 6e18e03e 2004-04-11 devnull .IR ublock .
577 6e18e03e 2004-04-11 devnull If less than three address expressions are given,
578 6e18e03e 2004-04-11 devnull the remaining parameters are left unchanged.
579 6e18e03e 2004-04-11 devnull If the list is terminated by
583 6e18e03e 2004-04-11 devnull then the file
584 6e18e03e 2004-04-11 devnull .RI ( textfile
586 6e18e03e 2004-04-11 devnull .I memfile
587 6e18e03e 2004-04-11 devnull respectively) is used
588 6e18e03e 2004-04-11 devnull for subsequent requests.
589 6e18e03e 2004-04-11 devnull For example,
593 6e18e03e 2004-04-11 devnull to refer to
594 6e18e03e 2004-04-11 devnull .IR textfile .
596 6e18e03e 2004-04-11 devnull .BI > name
597 6e18e03e 2004-04-11 devnull Dot is assigned to the variable or register named.
600 6e18e03e 2004-04-11 devnull The rest of the line is passed to
601 6e18e03e 2004-04-11 devnull .IR rc (1)
602 6e18e03e 2004-04-11 devnull for execution.
604 6e18e03e 2004-04-11 devnull .BI $ modifier
605 6e18e03e 2004-04-11 devnull Miscellaneous commands.
606 6e18e03e 2004-04-11 devnull The available
607 6e18e03e 2004-04-11 devnull .I modifiers
613 6e18e03e 2004-04-11 devnull Read commands from the file
615 6e18e03e 2004-04-11 devnull If this command is executed in a file, further commands
616 6e18e03e 2004-04-11 devnull in the file are not seen.
619 6e18e03e 2004-04-11 devnull is omitted, the current input stream is terminated.
621 6e18e03e 2004-04-11 devnull .I count
622 6e18e03e 2004-04-11 devnull is given, and is zero, the command is ignored.
624 6e18e03e 2004-04-11 devnull .BI << f
625 6e18e03e 2004-04-11 devnull Similar to
627 6e18e03e 2004-04-11 devnull except it can be used in a file of commands without
628 6e18e03e 2004-04-11 devnull causing the file to be closed.
629 6e18e03e 2004-04-11 devnull There is a (small) limit to the number of
631 6e18e03e 2004-04-11 devnull files that can be open at once.
636 6e18e03e 2004-04-11 devnull Append output to the file
638 6e18e03e 2004-04-11 devnull which is created if it does not exist.
641 6e18e03e 2004-04-11 devnull is omitted, output is returned to the terminal.
644 6e18e03e 2004-04-11 devnull Print process id, the condition which caused stopping or termination,
645 6e18e03e 2004-04-11 devnull the registers and the instruction addressed by
646 6e18e03e 2004-04-11 devnull .BR pc .
647 6e18e03e 2004-04-11 devnull This is the default if
648 6e18e03e 2004-04-11 devnull .I modifier
649 6e18e03e 2004-04-11 devnull is omitted.
652 6e18e03e 2004-04-11 devnull Print the general registers and
653 6e18e03e 2004-04-11 devnull the instruction addressed by
654 6e18e03e 2004-04-11 devnull .BR pc .
655 6e18e03e 2004-04-11 devnull Dot is set to
656 6e18e03e 2004-04-11 devnull .BR pc .
660 6e18e03e 2004-04-11 devnull .BR $r ,
661 6e18e03e 2004-04-11 devnull but include miscellaneous processor control registers
662 6e18e03e 2004-04-11 devnull and floating point registers.
665 6e18e03e 2004-04-11 devnull Print floating-point register values as
666 6e18e03e 2004-04-11 devnull single-precision floating point numbers.
669 6e18e03e 2004-04-11 devnull Print floating-point register values as
670 6e18e03e 2004-04-11 devnull double-precision floating point numbers.
673 6e18e03e 2004-04-11 devnull Print all breakpoints
674 6e18e03e 2004-04-11 devnull and their associated counts and commands. `B' produces the same results.
677 6e18e03e 2004-04-11 devnull Stack backtrace.
679 6e18e03e 2004-04-11 devnull .I address
680 6e18e03e 2004-04-11 devnull is given, it specifies the address of a pair of 32-bit
681 6e18e03e 2004-04-11 devnull values containing the
685 6e18e03e 2004-04-11 devnull of an active process. This allows selecting
686 6e18e03e 2004-04-11 devnull among various contexts of a multi-threaded
687 6e18e03e 2004-04-11 devnull process.
690 6e18e03e 2004-04-11 devnull is used, the names and (long) values of all
691 6e18e03e 2004-04-11 devnull parameters,
692 6e18e03e 2004-04-11 devnull automatic
693 6e18e03e 2004-04-11 devnull and static variables are printed for each active function.
695 6e18e03e 2004-04-11 devnull .I count
696 6e18e03e 2004-04-11 devnull is given, only the first
697 6e18e03e 2004-04-11 devnull .I count
698 6e18e03e 2004-04-11 devnull frames are printed.
701 6e18e03e 2004-04-11 devnull Attach to the running process whose pid
702 6e18e03e 2004-04-11 devnull is contained in
703 6e18e03e 2004-04-11 devnull .IR address .
706 6e18e03e 2004-04-11 devnull The names and values of all
707 6e18e03e 2004-04-11 devnull external variables are printed.
710 6e18e03e 2004-04-11 devnull Set the page width for output to
711 6e18e03e 2004-04-11 devnull .I address
712 6e18e03e 2004-04-11 devnull (default 80).
715 6e18e03e 2004-04-11 devnull Exit from
716 6e18e03e 2004-04-11 devnull .IR db .
719 6e18e03e 2004-04-11 devnull Print the address maps.
722 6e18e03e 2004-04-11 devnull Simulate kernel memory management.
724 6e18e03e 2004-04-11 devnull .BI M machine
726 6e18e03e 2004-04-11 devnull .I machine
727 6e18e03e 2004-04-11 devnull type used for disassembling instructions.
731 6e18e03e 2004-04-11 devnull .BI : modifier
732 6e18e03e 2004-04-11 devnull Manage a subprocess.
733 6e18e03e 2004-04-11 devnull Available modifiers are:
739 6e18e03e 2004-04-11 devnull an asynchronously running process to allow breakpointing.
740 6e18e03e 2004-04-11 devnull Unnecessary for processes created under
741 6e18e03e 2004-04-11 devnull .IR db ,
743 6e18e03e 2004-04-11 devnull .BR :r .
746 6e18e03e 2004-04-11 devnull Set breakpoint at
747 6e18e03e 2004-04-11 devnull .IR address .
748 6e18e03e 2004-04-11 devnull The breakpoint is executed
749 6e18e03e 2004-04-11 devnull .IR count \-1
750 6e18e03e 2004-04-11 devnull times before
751 6e18e03e 2004-04-11 devnull causing a stop.
752 6e18e03e 2004-04-11 devnull Also, if a command
754 6e18e03e 2004-04-11 devnull is given it is executed at each
755 6e18e03e 2004-04-11 devnull breakpoint and if it sets dot to zero
756 6e18e03e 2004-04-11 devnull the breakpoint causes a stop.
759 6e18e03e 2004-04-11 devnull Delete breakpoint at
760 6e18e03e 2004-04-11 devnull .IR address .
764 6e18e03e 2004-04-11 devnull .I textfile
765 6e18e03e 2004-04-11 devnull as a subprocess.
767 6e18e03e 2004-04-11 devnull .I address
768 6e18e03e 2004-04-11 devnull is given the
769 6e18e03e 2004-04-11 devnull program is entered at that point; otherwise
770 6e18e03e 2004-04-11 devnull the standard entry point is used.
771 6e18e03e 2004-04-11 devnull .I Count
772 6e18e03e 2004-04-11 devnull specifies how many breakpoints are to be
773 6e18e03e 2004-04-11 devnull ignored before stopping.
774 6e18e03e 2004-04-11 devnull Arguments to the subprocess may be supplied on the
775 6e18e03e 2004-04-11 devnull same line as the command.
776 6e18e03e 2004-04-11 devnull An argument starting with < or > causes the standard
777 6e18e03e 2004-04-11 devnull input or output to be established for the command.
780 6e18e03e 2004-04-11 devnull The subprocess is continued.
783 6e18e03e 2004-04-11 devnull is omitted
784 6e18e03e 2004-04-11 devnull or nonzero,
785 6e18e03e 2004-04-11 devnull the subprocess
786 6e18e03e 2004-04-11 devnull is sent the note that caused it to stop.
788 6e18e03e 2004-04-11 devnull is specified,
789 6e18e03e 2004-04-11 devnull no note is sent.
790 6e18e03e 2004-04-11 devnull (If the stop was due to a breakpoint or single-step,
791 6e18e03e 2004-04-11 devnull the corresponding note is elided before continuing.)
792 6e18e03e 2004-04-11 devnull Breakpoint skipping is the same
799 6e18e03e 2004-04-11 devnull except that
800 6e18e03e 2004-04-11 devnull the subprocess is single stepped for
801 6e18e03e 2004-04-11 devnull .I count
802 6e18e03e 2004-04-11 devnull machine instructions.
803 6e18e03e 2004-04-11 devnull If a note is pending,
804 6e18e03e 2004-04-11 devnull it is received
805 6e18e03e 2004-04-11 devnull before the first instruction is executed.
806 6e18e03e 2004-04-11 devnull If there is no current subprocess then
807 6e18e03e 2004-04-11 devnull .I textfile
809 6e18e03e 2004-04-11 devnull as a subprocess as for
811 6e18e03e 2004-04-11 devnull In this case no note can be sent; the remainder of the line
812 6e18e03e 2004-04-11 devnull is treated as arguments to the subprocess.
815 6e18e03e 2004-04-11 devnull Identical to
817 6e18e03e 2004-04-11 devnull except the subprocess is single stepped for
818 6e18e03e 2004-04-11 devnull .I count
819 6e18e03e 2004-04-11 devnull lines of C source. In optimized code, the correspondence
820 6e18e03e 2004-04-11 devnull between C source and the machine instructions is
821 6e18e03e 2004-04-11 devnull approximate at best.
824 6e18e03e 2004-04-11 devnull The current subprocess, if any, is released by
826 6e18e03e 2004-04-11 devnull and allowed to continue executing normally.
829 6e18e03e 2004-04-11 devnull The current subprocess, if any, is terminated.
832 6e18e03e 2004-04-11 devnull Display the pending notes for the process.
835 6e18e03e 2004-04-11 devnull is specified, first delete
837 6e18e03e 2004-04-11 devnull pending note.
840 6e18e03e 2004-04-11 devnull .SS Addresses
841 6e18e03e 2004-04-11 devnull The location in a file or memory image associated with
842 6e18e03e 2004-04-11 devnull an address is calculated from a map
843 6e18e03e 2004-04-11 devnull associated with the file.
844 6e18e03e 2004-04-11 devnull Each map contains one or more quadruples
845 6e18e03e 2004-04-11 devnull .RI ( "t, f, b, e, o" ),
846 6e18e03e 2004-04-11 devnull defining a segment named
848 6e18e03e 2004-04-11 devnull (usually,
849 6e18e03e 2004-04-11 devnull .IR text ,
850 6e18e03e 2004-04-11 devnull .IR data ,
852 6e18e03e 2004-04-11 devnull .IR core )
855 6e18e03e 2004-04-11 devnull mapping addresses in the range
859 6e18e03e 2004-04-11 devnull to the part of the file
860 6e18e03e 2004-04-11 devnull beginning at
863 6e18e03e 2004-04-11 devnull If segments overlap, later segments obscure earlier ones.
864 6e18e03e 2004-04-11 devnull An address
866 6e18e03e 2004-04-11 devnull is translated
867 6e18e03e 2004-04-11 devnull to a file address
868 6e18e03e 2004-04-11 devnull by finding the last segment in the list
869 6e18e03e 2004-04-11 devnull for which
870 6e18e03e 2004-04-11 devnull .IR b ≤ a < e ;
871 6e18e03e 2004-04-11 devnull the location in the file
873 6e18e03e 2004-04-11 devnull .IR address + f \- b .
875 6e18e03e 2004-04-11 devnull Usually,
876 6e18e03e 2004-04-11 devnull the text and initialized data of a program
877 6e18e03e 2004-04-11 devnull are mapped by segments called
878 6e18e03e 2004-04-11 devnull .IR text ,
879 6e18e03e 2004-04-11 devnull .IR data ,
881 6e18e03e 2004-04-11 devnull .IR bss .
882 6e18e03e 2004-04-11 devnull Since a program file does not contain stack data,
883 6e18e03e 2004-04-11 devnull this data is
884 6e18e03e 2004-04-11 devnull not mapped.
885 6e18e03e 2004-04-11 devnull The text segment is mapped similarly in
886 6e18e03e 2004-04-11 devnull a normal (i.e., non-kernel)
887 6e18e03e 2004-04-11 devnull .IR memfile .
888 6e18e03e 2004-04-11 devnull However, one or more segments called
890 6e18e03e 2004-04-11 devnull provide access to process memory.
891 6e18e03e 2004-04-11 devnull This region contains the program's static data, the bss, the
892 6e18e03e 2004-04-11 devnull heap and the stack.
894 6e18e03e 2004-04-11 devnull Sometimes it is useful to define a map with a single segment
895 6e18e03e 2004-04-11 devnull mapping the region from 0 to 0xFFFFFFFF; a map of this type
896 6e18e03e 2004-04-11 devnull allows an entire file to be examined
897 6e18e03e 2004-04-11 devnull without address translation.
901 6e18e03e 2004-04-11 devnull command dumps the currently active maps. The
905 6e18e03e 2004-04-11 devnull commands modify the segment parameters in the
906 6e18e03e 2004-04-11 devnull .I textfile
908 6e18e03e 2004-04-11 devnull .I memfile
909 6e18e03e 2004-04-11 devnull maps, respectively.
910 6e18e03e 2004-04-11 devnull .SH EXAMPLES
911 6e18e03e 2004-04-11 devnull To set a breakpoint at the beginning of
912 6e18e03e 2004-04-11 devnull .B write()
913 6e18e03e 2004-04-11 devnull in extant process 27:
930 6e18e03e 2004-04-11 devnull To set a breakpoint at the entry of function
931 6e18e03e 2004-04-11 devnull .B parse
932 6e18e03e 2004-04-11 devnull when the local variable
936 6e18e03e 2004-04-11 devnull is equal to 1:
939 6e18e03e 2004-04-11 devnull parse:b *main.argc-1=X
942 6e18e03e 2004-04-11 devnull This prints the value of
943 6e18e03e 2004-04-11 devnull .B argc-1
944 6e18e03e 2004-04-11 devnull which as a side effect sets dot; when
946 6e18e03e 2004-04-11 devnull is one the breakpoint will fire.
947 6e18e03e 2004-04-11 devnull Beware that local variables may be stored in registers; see the
948 6e18e03e 2004-04-11 devnull BUGS section.
949 6e18e03e 2004-04-11 devnull .SH "SEE ALSO"
950 6e18e03e 2004-04-11 devnull .IR acid (1)
951 6e18e03e 2004-04-11 devnull .SH SOURCE
952 b5fdffee 2004-04-19 devnull .B /usr/local/plan9/src/cmd/db
953 6e18e03e 2004-04-11 devnull .SH DIAGNOSTICS
954 6e18e03e 2004-04-11 devnull Exit status is 0, unless the last command failed or
955 6e18e03e 2004-04-11 devnull returned non-zero status.
956 6e18e03e 2004-04-11 devnull .SH BUGS
957 6e18e03e 2004-04-11 devnull Examining a local variable with
958 6e18e03e 2004-04-11 devnull .I routine.name
959 6e18e03e 2004-04-11 devnull returns the contents of the memory allocated for the variable, but
960 6e18e03e 2004-04-11 devnull with optimization, variables often reside in registers.
961 6e18e03e 2004-04-11 devnull Also, on some architectures, the first argument is always
962 6e18e03e 2004-04-11 devnull passed in a register.
964 6e18e03e 2004-04-11 devnull Variables and parameters that have been
965 6e18e03e 2004-04-11 devnull optimized away do not appear in the
966 6e18e03e 2004-04-11 devnull symbol table, returning the error
967 6e18e03e 2004-04-11 devnull .IR "bad local variable"
968 6e18e03e 2004-04-11 devnull when accessed by
969 6e18e03e 2004-04-11 devnull .IR db .
971 6e18e03e 2004-04-11 devnull Breakpoints should not be set on instructions scheduled
972 6e18e03e 2004-04-11 devnull in delay slots. When a program stops on such a breakpoint,
973 6e18e03e 2004-04-11 devnull it is usually impossible to continue its execution.
