Summary of GDB commands for x86-64 Systems

原文： http://csapp.cs.cmu.edu/2e/docs/gdbnotes-x86-64.pdf

Summary of GDB commands for x86-64 Systems

Starting:

 gdb
 gdb <file>

Running and stopping

Command	Effect
quit	Exit gdb
run	Run program
run 1 2 3	Run program with command-line arguments 1 2 3
kill	Stop the program
quit	Exit gdb
Ctrl-d	Exit gdb

Note: Ctrl-Cdoes not exit from gdb, but halts the current
gdb command

Breakpoints

Command	Effect
break sum	Set breakpoint at the entry to function sum
break *0x80483c3	Set breakpoint at address 0x80483c3
delete 1	Delete breakpoint 1
disable 1	Disable the breakpoint 1 (gdb numbers each breakpoint you create)
enable 1	Enable breakpoint 1
delete	Delete all breakpoints
clear sum	Clear any breakpoints at the entry to function sum

Execution

Command	Effect
stepi	Execute one instruction
stepi 4	Execute four instructions
nexti	Like stepi, but proceed through function calls without stopping
step	Execute one C statement
continue	Resume execution until the next breakpoint
until 3	Continue executing until program hits breakpoint 3
finish	Resume execution until current function returns
call sum(1, 2)	Call sum(1,2) and print return value

Examining code

Command	Effect
disas	Disassemble current function
disas sum	Disassemble function sum
disas 0x80483b7	Disassemble function around 0x80483b7
disas 0x80483b7 0x80483c7	Disassemble code within specified address range
print /x $rip	Print program counter in hex
print /d $rip	Print program counter in decimal
print /t $rip	Print program counter in binary

Examining data

Command	Effect
print /d $rax	Print contents of %rax in decimal
print /x $rax	Print contents of %rax in hex
print /t $rax	Print contents of %rax in binary
print /d (int)$rax	Print contents of %rax in decimal after sign-extending lower 32-bits.

You need this to print 32-bit, negative numbers stored in the lower 32 bits of %rax. For example, if the lower 32-bits of %rax store 0xffffffff, you will see
(gdb) print $rax
$1 = 4294967295
(gdb) print (int)$rax
$2 = -1
(gdb)

Command	Effect
print 0x100	Print decimal representation of 0x100
print /x 555	Print hex representation of 555
print /x ($rsp+8)	Print (contents of %rsp) + 8 in hex
print *(int *) 0xbffff890	Print integer at address 0xbffff890
print *(int *) ($rsp+8)	Print integer at address %rsp + 8
print (char *) 0xbfff890	Examine a string stored at 0xbffff890
x/w 0xbffff890	Examine (4-byte) word starting at address 0xbffff890
x/w $rsp	Examine (4-byte) word starting at address in $rsp
x/wd $rsp	Examine (4-byte) word starting at address in $rsp. Print in decimal
x/2w $rsp	Examine two (4-byte) words starting at address in $rsp
x/2wd $rsp	Examine two (4-byte) words starting at address in $rsp. Print in decimal
x/g $rsp	Examine (8-byte) word starting at address in $rsp.
x/gd $rsp	Examine (8-byte) word starting at address in $rsp. Print in decimal
x/a $rsp	Examine address in $rsp. Print as offset from previous global symbol.
x/s 0xbffff890	Examine a string stored at 0xbffff890
x/20b sum	Examine first 20 opcode bytes of function sum
x/10i sum	Examine first 10 instructions of function sum

(Note: the format string for the ‘x’ command has the general form x/[NUM][SIZE][FORMAT] where
NUM = number of objects to display
SIZE = size of each object (b=byte, h=half-word, w=word, g=giant (quad-word))
FORMAT = how to display each object (d=decimal, x=hex, o=octal, etc.)
If you don’t specify SIZE or FORMAT, either a default value, or the last
value you specified in a previous ‘print’ or ‘x’ command is used. )

Useful information

Command	Effect
backtrace	Print the current address and stack backtrace
where	Print the current address and stack backtrace
info program	Print current status of the program)
info functions	Print functions in program
info stack	Print backtrace of the stack)
info frame	Print information about the current stack frame
info registers	Print registers and their contents
info breakpoints	Print status of user-settable breakpoints
display /FMT EXPR	Print expression EXPR using format FMT every time GDB stops
undisplay	Turn off display mode
help	Get information about gdb