WINEDBG

Section: Wine Developers Manual (1)
Updated: October 2005
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NAME

winedbg - Wine debugger

SYNOPSIS

winedbg [ options ] [ program_name [ program_arguments ] | wpid ]

winedbg --gdb [ options ] [ program_name [ program_arguments ] | wpid ]

winedbg --auto wpid

winedbg --minidump [ file.mdmp ] wpid

winedbg file.mdmp

DESCRIPTION

winedbg is a debugger for Wine. It allows:

+ debugging native Win32 applications
+ debugging Winelib applications
+ being a drop-in replacement for Dr Watson

MODES

winedbg can be used in five modes. The first argument to the program determines the mode winedbg will run in.

default: Without any explicit mode, this is standard winedbg operating mode. winedbg will act as the front end for the user.
--gdb: winedbg will be used as a proxy for gdb. gdb will be the front end for command handling, and winedbg will proxy all debugging requests from gdb to the Win32 APIs.
--auto: This mode is used when winedbg is set up in AeDebug registry entry as the default debugger. winedbg will then display basic information about a crash. This is useful for users who don't want to debug a crash, but rather gather relevant information about the crash to be sent to developers.
--minidump: This mode is similar to the --auto one, except that instead of printing the information on the screen (as --auto does), it's saved into a minidump file. The name of the file is either passed on the command line, or generated by WineDbg when none is given. This file could later on be reloaded into winedbg for further examination.
file.mdmp: In this mode winedbg reloads the state of a debuggee which has been saved into a minidump file. See either the minidump command below, or the --minidump mode.

OPTIONS

When in default mode, the following options are available:

--command string: winedbg will execute the command string as if it was keyed on winedbg command line, and then will exit. This can be handy for getting the pid of running processes (winedbg --command "info proc").
--file filename: winedbg will execute the list of commands contained in file filename as if they were keyed on winedbg command line, and then will exit.

When in gdb proxy mode, the following options are available:

--no-start: gdb will not be automatically started. Relevant information for starting gdb is printed on screen. This is somehow useful when not directly using gdb but some graphical front-ends, like ddd or kgbd.
--port port: Start the gdb server on the given port. If this option is not specified, a randomly chosen port will be used. If --no-start is specified, the port used will be printed on startup.
--with-xterm: This will run gdb in its own xterm instead of using the current Unix console for textual display.

In all modes, the rest of the command line, when passed, is used to identify which programs, if any, has to debugged:

program_name: This is the name of an executable to start for a debugging session. winedbg will actually create a process with this executable. If programs_arguments are also given, they will be used as arguments for creating the process to be debugged.
wpid: winedbg will attach to the process which Windows pid is wpid. Use the info proc command within winedbg to list running processes and their Windows pids.
default: If nothing is specified, you will enter the debugger without any run nor attached process. You'll have to do the job yourself.

COMMANDS

Default mode, and while reloading a minidump file:

Most of commands used in winedbg are similar to the ones from gdb. Please refer to the gdb documentations for some more details. See the gdb differences section later on to get a list of variations from gdb commands.

Misc. commands

abort: Aborts the debugger.
quit: Exits the debugger.
attach N: Attach to a Wine process (N is its Windows ID, numeric or hexadecimal). IDs can be obtained using the info process command. Note the info process command returns hexadecimal values

detach: Detach from a Wine-process.
thread N: Change the current thread to N (its Windows TID, numeric or hexadecimal).

Help commands

help: Prints some help on the commands.
help info: Prints some help on info commands

Flow control commands

cont: Continue execution until next breakpoint or exception.
pass: Pass the exception event up to the filter chain.
step: Continue execution until next C line of code (enters function call)
next: Continue execution until next C line of code (doesn't enter function call)
stepi: Execute next assembly instruction (enters function call)
nexti: Execute next assembly instruction (doesn't enter function call)
finish: Execute until return of current function is reached.

cont, step, next, stepi, nexti can be postfixed by a number (N), meaning that the command must be executed N times before control is returned to the user.

Breakpoints, watchpoints

enable N: Enables (break|watch)-point N
disable N: Disables (break|watch)-point N
delete N: Deletes (break|watch)-point N
cond N: Removes any existing condition to (break|watch)-point N
cond N expr: Adds condition expr to (break|watch)-point N. expr will be evaluated each time the (break|watch)-point is hit. If the result is a zero value, the breakpoint isn't triggered.
break * N: Adds a breakpoint at address N
break id: Adds a breakpoint at the address of symbol id
break id N: Adds a breakpoint at the line N inside symbol id.
break N: Adds a breakpoint at line N of current source file.
break: Adds a breakpoint at current $PC address.
watch * N: Adds a watch command (on write) at address N (on 4 bytes).
watch id: Adds a watch command (on write) at the address of symbol id. Size depends on size of id.
rwatch * N: Adds a watch command (on read) at address N (on 4 bytes).
rwatch id: Adds a watch command (on read) at the address of symbol id. Size depends on size of id.
info break: Lists all (break|watch)-points (with their state).

You can use the symbol EntryPoint to stand for the entry point of the Dll.

When setting a (break|watch)-point by id, if the symbol cannot be found (for example, the symbol is contained in a not yet loaded module), winedbg will recall the name of the symbol and will try to set the breakpoint each time a new module is loaded (until it succeeds).

Stack manipulation

bt: Print calling stack of current thread.
bt N: Print calling stack of thread of ID N. Note: this doesn't change the position of the current frame as manipulated by the up & dn commands).
up: Goes up one frame in current thread's stack
up N: Goes up N frames in current thread's stack
dn: Goes down one frame in current thread's stack
dn N: Goes down N frames in current thread's stack
frame N: Sets N as the current frame for current thread's stack.
info locals: Prints information on local variables for current function frame.

Directory & source file manipulation

show dir: Prints the list of dirs where source files are looked for.
dir pathname: Adds pathname to the list of dirs where to look for source files
dir: Deletes the list of dirs where to look for source files
symbolfile pathname: Loads external symbol definition file pathname
symbolfile pathname N: Loads external symbol definition file pathname (applying an offset of N to addresses)
list: Lists 10 source lines forwards from current position.
list -: Lists 10 source lines backwards from current position
list N: Lists 10 source lines from line N in current file
list pathname:N: Lists 10 source lines from line N in file pathname
list id: Lists 10 source lines of function id
list * N: Lists 10 source lines from address N

You can specify the end target (to change the 10 lines value) using the ',' separator. For example:

list 123, 234: lists source lines from line 123 up to line 234 in current file
list foo.c:1,56: lists source lines from line 1 up to 56 in file foo.c

Displaying

A display is an expression that's evaluated and printed after the execution of any winedbg command.

display
info display: Lists the active displays
display expr: Adds a display for expression expr
display /fmt expr: Adds a display for expression expr. Printing evaluated expr is done using the given format (see print command for more on formats)
del display N
undisplay N: Deletes display N

Disassembly

disas: Disassemble from current position
disas expr: Disassemble from address expr
disas expr,expr: Disassembles code between addresses specified by the two expressions

Memory (reading, writing, typing)

x expr: Examines memory at address expr
x /fmt expr: Examines memory at address expr using format fmt
print expr: Prints the value of expr (possibly using its type)
print /fmt expr: Prints the value of expr (possibly using its type)
set var = expr: Writes the value of expr in var variable
whatis expr: Prints the C type of expression expr

fmt

is either letter or count letter, where letter can be:

s: an ASCII string
u: a UTF16 Unicode string
i: instructions (disassemble)
x: 32-bit unsigned hexadecimal integer
d: 32-bit signed decimal integer
w: 16-bit unsigned hexadecimal integer
c: character (only printable 0x20-0x7f are actually printed)
b: 8-bit unsigned hexadecimal integer
g: Win32 GUID

Expressions

Expressions in Wine Debugger are mostly written in a C form. However, there are a few discrepancies:

: Identifiers can take a '!' in their names. This allows mainly to specify a module where to look the ID from, e.g. USER32!CreateWindowExA.
In a cast operation, when specifying a structure or a union, you must use the struct or union keyword (even if your program uses a typedef).

When specifying an identifier, if several symbols with this name exist, the debugger will prompt for the symbol you want to use. Pick up the one you want from its number.

Misc.

minidump file.mdmp saves the debugging context of the debuggee into a minidump file called file.mdmp.

Information on Wine internals

info class: Lists all Windows classes registered in Wine
info class id: Prints information on Windows class id
info share: Lists all the dynamic libraries loaded in the debugged program (including .so files, NE and PE DLLs)
info share N: Prints information on module at address N
info regs: Prints the value of the CPU registers
info all-regs: Prints the value of the CPU and Floating Point registers
info segment: Lists all allocated segments (i386 only)
info segment N: Prints information on segment N (i386 only)
info stack: Prints the values on top of the stack
info map: Lists all virtual mappings used by the debugged program
info map N: Lists all virtual mappings used by the program of Windows pid N
info wnd: Displays the window hierarchy starting from the desktop window
info wnd N: Prints information of Window of handle N
info process: Lists all w-processes in Wine session
info thread: Lists all w-threads in Wine session
info frame: Lists the exception frames (starting from current stack frame). You can also pass, as optional argument, a thread id (instead of current thread) to examine its exception frames.

Debug messages can be turned on and off as you are debugging using the set command, but only for channels initialized with the WINEDEBUG environment variable.

set warn + win: Turns on warn on win channel
set + win: Turns on warn/fixme/err/trace on win channel
set - win: Turns off warn/fixme/err/trace on win channel
set fixme - all: Turns off fixme class on all channels

Gdb mode:

See the gdb documentation for all the gdb commands.

However, a few Wine extensions are available, through the monitor command:

monitor wnd: Lists all windows in the Wine session
monitor proc: Lists all processes in the Wine session
monitor mem: Displays memory mapping of debugged process

Auto and minidump modes:

Since no user input is possible, no commands are available.

ENVIRONMENT

WINE_GDB: When used in gdb proxy mode, WINE_GDB specifies the name (and the path) of the executable to be used for gdb. "gdb" is used by default.

AUTHORS

The first version was written by Eric Youngdale.

See Wine developers list for the rest of contributors.

BUGS

Bugs can be reported on the Wine bug tracker

AVAILABILITY

winedbg is part of the Wine distribution, which is available through WineHQ, the Wine development headquarters