💾 Archived View for radare.org › book › scripting › loops.gmi captured on 2023-11-04 at 11:50:13. Gemini links have been rewritten to link to archived content
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One of the most common task in automation is looping through something, there are multiple ways to do this in radare2.
We can loop over flags: ``` @@ flagname-regex ```
For example, we want to see function information with `afi` command: ``` [0x004047d6]> afi # offset: 0x004047d0 name: entry0 size: 42 realsz: 42 stackframe: 0 call-convention: amd64 cyclomatic-complexity: 1 bits: 64 type: fcn [NEW] num-bbs: 1 edges: 0 end-bbs: 1 call-refs: 0x00402450 C data-refs: 0x004136c0 0x00413660 0x004027e0 code-xrefs:
data-xrefs: locals:0 args: 0 diff: type: new [0x004047d6]> ``` Now let's say, for example, that we'd like see a particular field from this output for all functions found by analysis. We can do that with a loop over all function flags (whose names begin with `fcn.`):
[0x004047d6]> fs functions [0x004047d6]> afi @@ fcn.* ~name
This command will extract the `name` field from the `afi` output of every flag with a name matching the regexp `fcn.*`.
There are also a predefined loop called `@@f`, which runs your command on every functions found by r2: ``` [0x004047d6]> afi @@f ~name ```
We can also loop over a list of offsets, using the following syntax: ``` @@=1 2 3 ... N ``` For example, say we want to see the opcode information for 2 offsets: the current one, and at current + 2:
[0x004047d6]> ao @@=$ $+2
address: 0x4047d6
opcode: mov rdx, rsp
prefix: 0
bytes: 4889e2
refptr: 0
size: 3
type: mov
esil: rsp,rdx,=
stack: null
family: cpu
address: 0x4047d8
opcode: loop 0x404822
prefix: 0
bytes: e248
refptr: 0
size: 2
type: cjmp
esil: 1,rcx,-=,rcx,?{,4212770,rip,=,}
jump: 0x00404822
fail: 0x004047da
stack: null
cond: al
family: cpu
[0x004047d6]>
Note we're using the `$` variable which evaluates to the current offset. Also note that `$+2` is evaluated before looping, so we can use the simple arithmetic expressions.
A third way to loop is by having the offsets be loaded from a file. This file should contain one offset per line.
[0x004047d0]> ?v $ > offsets.txt [0x004047d0]> ?v $+2 >> offsets.txt [0x004047d0]> !cat offsets.txt 4047d0 4047d2 [0x004047d0]> pi 1 @@.offsets.txt xor ebp, ebp mov r9, rdx
radare2 also offers various `foreach` constructs for looping. One of the most useful is for looping through all the instructions of a function: ``` [0x004047d0]> pdf / (fcn) entry0 42 |; UNKNOWN XREF from 0x00400018 (unk) |; DATA XREF from 0x004064bf (sub.strlen_460) |; DATA XREF from 0x00406511 (sub.strlen_460) |; DATA XREF from 0x0040b080 (unk) |; DATA XREF from 0x0040b0ef (unk) |0x004047d0 xor ebp, ebp |0x004047d2 mov r9, rdx |0x004047d5 pop rsi |0x004047d6 mov rdx, rsp |0x004047d9 and rsp, 0xfffffffffffffff0 |0x004047dd push rax |0x004047de push rsp |0x004047df mov r8, 0x4136c0 |0x004047e6 mov rcx, 0x413660 ; "AWA..AVI..AUI..ATL.%.. " 0A..AVI..AUI.
|0x004047ed mov rdi, main ; "AWAVAUATUH..S..H...." @ 0 |0x004047f4 call sym.imp.__libc_start_main \0x004047f9 hlt [0x004047d0]> pi 1 @@i mov r9, rdx pop rsi mov rdx, rsp and rsp, 0xfffffffffffffff0 push rax push rsp mov r8, 0x4136c0 mov rcx, 0x413660 mov rdi, main call sym.imp.__libc_start_main hlt ``` In this example the command `pi 1` runs over all the instructions in the current function (entry0).
There are other options too (not complete list, check `@@?` for more information): - `@@k sdbquery` - iterate over all offsets returned by that sdbquery - `@@t`- iterate over on all threads (see dp) - `@@b` - iterate over all basic blocks of current function (see afb) - `@@f` - iterate over all functions (see aflq)
The last kind of looping lets you loop through predefined iterator types:
- symbols
- imports
- registers
- threads
- comments
- functions
- flags
This is done using the `@@@` command. The previous example of listing information about functions can also be done using the `@@@` command:
[0x004047d6]> afi @@@ functions ~name
This will extract `name` field from `afi` output and will output a huge list of function names. We can choose only the second column, to remove the redundant `name:` on every line:
[0x004047d6]> afi @@@ functions ~name[1]