Heap
radare2's dm subcommands can also display a map of the heap which is useful for those who are interested in inspecting the heap and its content. Simply execute dmh to show a map of the heap:
[0x7fae46236ca6]> dmh
Malloc chunk @ 0x55a7ecbce250 [size: 0x411][allocated]
Top chunk @ 0x55a7ecbce660 - [brk_start: 0x55a7ecbce000, brk_end: 0x55a7ecbef000]
You can also see a graph layout of the heap:
[0x7fae46236ca6]> dmhg
Heap Layout
.------------------------------------.
| Malloc chunk @ 0x55a7ecbce000 |
| size: 0x251 |
| fd: 0x0, bk: 0x0 |
`------------------------------------'
|
.---'
|
|
.---------------------------------------------.
| Malloc chunk @ 0x55a7ecbce250 |
| size: 0x411 |
| fd: 0x57202c6f6c6c6548, bk: 0xa21646c726f |
`---------------------------------------------'
|
.---'
|
|
.----------------------------------------------------.
| Top chunk @ 0x55a7ecbce660 |
| [brk_start:0x55a7ecbce000, brk_end:0x55a7ecbef000] |
`----------------------------------------------------'
Another heap commands can be found under dmh, check dmh? for the full list.
[0x00000000]> dmh?
|Usage: dmh # Memory map heap
| dmh List chunks in heap segment
| dmh [malloc_state] List heap chunks of a particular arena
| dmha List all malloc_state instances in application
| dmhb Display all parsed Double linked list of main_arena's bins instance
| dmhb [bin_num|bin_num:malloc_state] Display parsed double linked list of bins instance from a particular arena
| dmhbg [bin_num] Display double linked list graph of main_arena's bin [Under developemnt]
| dmhc @[chunk_addr] Display malloc_chunk struct for a given malloc chunk
| dmhf Display all parsed fastbins of main_arena's fastbinY instance
| dmhf [fastbin_num|fastbin_num:malloc_state] Display parsed single linked list in fastbinY instance from a particular arena
| dmhg Display heap graph of heap segment
| dmhg [malloc_state] Display heap graph of a particular arena
| dmhi @[malloc_state]Display heap_info structure/structures for a given arena
| dmhm List all elements of struct malloc_state of main thread (main_arena)
| dmhm [malloc_state] List all malloc_state instance of a particular arena
| dmht Display all parsed thead cache bins of main_arena's tcache instance
| dmh? Show map heap help
To print safe-linked lists (glibc >= 2.32) with demangled pointers, the variable dbg.glibc.demangle must be true.