The command permits the user to open a file, this is mapped at offset 0 unless it has a known binary header and then the maps are created in virtual addresses.

    Sometimes, we want to rebase a binary, or maybe we want to load or map the file in a different address.

    When launching r2, the base address can be changed with the -B flag. But you must notice the difference when opening files with unknown headers, like bootloaders, so we need to map them using the -m flag (or specifying it as argument to the o command).

    Opening files (and mapping them) is done using the o (open) command. Let’s read the help:

    Prepare a simple layout:

    1. $ rabin2 -l /bin/ls
    3. libselinux.so.1
    4. libacl.so.1
    5. libc.so.6

    Map a file:

    1. [0x00000000]> o
    2. - 6 /bin/ls @ 0x0 ; r
    3. - 10 /lib/ld-linux.so.2 @ 0x100000000 ; r

    Print hexadecimal values from /bin/zsh:

    Unmap files using the o- command. Pass the required file descriptor to it as an argument:

    You can also view the ascii table showing the list of the opened files: