blob: 8411f194800b15e7012a6ef3d1976feaa09b0fb1 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
###################################################################
###################### #############################
### GDB COMMANDS ###
###################### #############################
###################################################################
QEMU CONFIGURATION
qemu must be started with "-s" option
(shorthand for "-gdb tcp::1234")
#
# GDB PART
#
SYMBOL FILES
add-symbol-file /path/to/Hello.debug 0x... -s .data 0x...
CONNECTION
- source gdbscript
(if a gdbscript is created, which contains
add-symbol-file commandos)
- target remote localhost:1234
DISCONNECTION
- detach
break connection with target, target resumes execution
GDB Target
(RSP Client) (RSP Server)
D
O------------------------------>O
O RSP exchange
O<------------------------------O
OK
-disconnect
Simply break connection. Target stays at the point where execution terminated previously
Reconnection(target remote): resume debugging at the point where the previous connection was broken
BREAKPOINTS
- b CoreHandleProtocol || or OutputString
- break *0x65fe447 || set breakpoint at address
- delete 2 || delete breakpoint no 2
- break sampleApp.c:nn=LineNumber
INFORMATION
- info
address SYM || Get address for symbol SYM
symbol ADDR || Show symbol at specified address
all-registers || all registers & their contents
breakpoints
files || get Entry point + sections
files || Names of targets & files being debugged
functions || all function names in Program
functions UefiMain || show where this function occurs
line
types [regex] || list all types or with regex
args || Argument variables of current stack frame
locals || local variables of current stack frame
variables || all gloabl & static variables
CONTROL FLOW
- c || continue
- next || move only one step forward
- bt || print back_trace of all stack frames
- stop || stop program until it reaches a different source line
FILES (perhaps not applicable when debugging with QEMU)
- file MemtestEfi.efi || load file ...no debugging symbols found...done
- file || unload files
LIST
- list || list specified function or line
gdb --tui
- layout asm
- layout reg
- layout src
- tui enable
- tui disable
- next
- ctrl+x o || change active window
- ctrl+x 1 || use TUI layout with one window
- ctrl+x 2 || use TUI layout with two windows
- PgUp || scroll the active window one page up
- PgDn || scroll the active window one page down
- Up || scroll the active window one line up
- Down || scroll the active window one lin down
- Right
- Left
- C+L || refresh the screen
VARIABLES
info locals
info variables
info args
|| Set is the same as print except that the expression's value is not printed
|| and is not put in the value history.
|| if your program has a variable width, you get an error if you try to set
|| a new value with just ‘set width=13’, because GDB has the command set width
|| To avoid to set silently general variables to invalid values, ALWAYS use
|| set var x=4
print x=4
set x=4 or set variable x=4
whatis x -> type = double
DISSASEMBLE BINARIES
gdb -batch -ex 'file /bin/ls' -ex 'disassemble main'
Also, -ex 'set disassembly-flavor intel' before other -exs will result in Intel assembly syntax
gcc -O0 -ggdb3 -std=c99 -Wall -Wextra -pedantic -o main.out main.c
gdb -batch -ex "disassemble/rs myfunc" main.out
|
