英文:
Assign string stored in memory into a GDB variable
问题
当调试C程序时，如何将存储在某个已知内存位置上的字符串（以\0字节结尾的字芍数组）分配给GDB方便变量？
例如：
有一个字符串"hello_world"存储在内存位置0xAAAAAAAA，如何使用该内存位置将字符串存储到GDB变量string_variable中？使用(gdb) set $string_Variable = (char *) 0xAAAAAAAA会存储地址而不是字符串本身。
英文:
When debugging a C program, how can I assign a string (array of bytes terminated by \0 byte) stored at some known memory location into a GDB convenience variable?
E.g.:
There is a string "hello_world" stored at memory location 0xAAAAAAAA, how can I store the string into a GDB variable string_variable using that memory location? Using (gdb) set $string_Variable = (char *) 0xAAAAAAAA stores the address and not the string itself.
答案1
得分: 2
在GDB中，字符串方便变量是一个char数组：
(gdb) set $foo = "bbb"
(gdb) ptype $foo
type = char [4]
使用GDB的CLI，我找不到一种直接从调试目标的NUL结尾字节字符串地址创建字符串方便变量的方法。
有效的方法是使用GDB的Python扩展从调试目标获取gdb.Value，然后将其转换为字符串：
(gdb) python gdb.set_convenience_variable("string_variable", gdb.parse_and_eval("(char *)0x555555556011").string())
(gdb) ptype $string_variable
type = char [12]
(gdb) p $string_variable
$3 = "hello_world"
英文:
A string convenience variable in GDB is an array of char:
(gdb) set $foo = "bbb"
(gdb) ptype $foo
type = char [4]
Using GDB's CLI, I can't find a straightforward way to create a string convenience variable from an address of a NUL-terminated string of bytes in the debuggee.
What does work is to use GDB's Python extension to get a gdb.Value from the debuggee, then convert it to a string:
(gdb) python gdb.set_convenience_variable("string_variable", gdb.parse_and_eval("(char *)0x555555556011").string())
(gdb) ptype $string_variable
type = char [12]
(gdb) p $string_variable
$3 = "hello_world"
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