BINMISCCTL(8)

NAME
binmiscctl - manage binary image activators

SYNOPSIS
binmiscctl add name --interpreter path --magic magic --size size [--mask mask] [--offset offset] [--set-enabled] [--pre-open]
binmiscctl disable name
binmiscctl enable name
binmiscctl list
binmiscctl lookup name
binmiscctl remove name

DESCRIPTION
The binmiscctl utility is the management utility for configuring miscellaneous binaries image activators in the kernel. It allows adding, deleting, disabling, enabling, and looking up interpreters. Also, all the interpreters can be listed.

The first argument on the command line indicates the operation to be performed. Operation must be one of the following:

    add name --interpreter path --magic magic --size size [--mask mask] [--offset offset] [--set-enabled] [--pre-open] Add a new activator entry in the kernel. You must specify a unique name, a path to the interpreter, header magic bytes that uniquely identify a suitable binary for the activator, and the size of the magic in bytes.

    Optionally, you may specify a mask to do a bitwise AND with the header bytes. This effectively allows you to ignore fields in the binary header that do not uniquely indentify the binary file's type.

    An offset may be specified for the magic bytes using the --offset option. By default the offset is zero.

    To enable the activator entry the --set-enabled option is used. The activator default state is disabled.

    To make the interpreter automatically available in jails and chroots, use the --pre-open option to allow the kernel to open the binary at configuration time rather then lazily when the interpreted program is started.

    The interpreter path may also contain arguments for the interpreter including #a which gets replaced by the old argv0 value in the interpreter string.

disable name
    Disable the activator entry identified with name.

enable name
    Enable the activator entry identified with name.

list
    Take a snapshot and print all the activator entries currently configured.

lookup name
    Look up and print out the activator entry identified with name.

remove name
    Remove the activator entry identified with name.

EXAMPLES
Add an image activator to run the LLVM interpreter ( lli(1)) on bitcode compiled files and set its state to enabled. In this example #a is replaced with the old argv0 value so that lli(1) can fake its argv0:

    # binmiscctl add llvmbc --interpreter ''/usr/bin/lli \
      --fake-argv0=#a'' --magic ''BC\xc0\xde'' --size 4 \
      --set-enabled

Set the state of the llvmbc image activator to disabled:

    # binmiscctl disable llvmbc

Set the state of the llvmbc image activator to enabled:

    # binmiscctl enable llvmbc

Delete the llvmbc image activator:

    # binmiscctl remove llvmbc

Look up and list the record for the llvmbc image activator:

    # binmiscctl lookup llvmbc

Add QEMU bsd-user program as an image activator for ARM AARCH64 binaries:

    # binmiscctl add arm64 \
      --interpreter "/usr/local/bin/qemu-aarch64-static" \
      --magic "\x7f\x45\x4c\x46\x02\x01\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for ARM little-endian binaries:

    # binmiscctl add armelf \
      --interpreter "/usr/local/bin/qemu-arm-static" \
      --magic "\x7f\x45\x4c\x46\x01\x01\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x02\x00\x28\x00" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for ARM big-endian binaries:

    # binmiscctl add armebelf \
      --interpreter "/usr/local/bin/qemu-arm-static" \
      --magic "\x7f\x45\x4c\x46\x01\x02\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x00\x02\x00\x28" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for MIPS32 binaries:

    # binmiscctl add mips32 \
      --interpreter "/usr/local/bin/qemu-mips-static" \
      --magic "\x7f\x45\x4c\x46\x01\x02\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x00\x02\x00\x08" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for MIPS64 binaries:

    # binmiscctl add mips64 \
      --interpreter "/usr/local/bin/qemu-mips64-static" \
      --magic "\x7f\x45\x4c\x46\x02\x02\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x00\x02\x00\x08" \
      --mask "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
              \xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for PowerPC binaries:

    # binmiscctl add powerpc \
      --interpreter "/usr/local/bin/qemu-ppc-static" \
      --magic "\x7f\x45\x4c\x46\x01\x02\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x00\x02\x00\x14" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for PowerPC64 binaries:

    # binmiscctl add powerpc64 \
      --interpreter "/usr/local/bin/qemu-ppc64-static" \
      --magic "\x7f\x45\x4c\x46\x02\x02\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x00\x02\x00\x15" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff" \
      --size 20 --set-enabled

Add QEMU bsd-user program as an image activator for 64-bit RISC-V binaries:

    # binmiscctl add riscv64 \
      --interpreter "/usr/local/bin/qemu-riscv64-static" \
      --magic "\x7f\x45\x4c\x46\x02\x01\x01\x00\x00\x00\
               \x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00" \
      --mask  "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\
               \xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff" \
      --size 20 --set-enabled

  Create and use an ARMv7 chroot on an AMD64 host
Use an existing source tree to build a chroot host with architecture overrides:

    D=/path/to/chroot
    cd /usr/src
    mkdir -p $D
    make world TARGET=arm TARGET_ARCH=armv7 DESTDIR=$D
    make distribution TARGET=arm TARGET_ARCH=armv7 DESTDIR=$D

With emulators/qemu-user-static from the FreeBSD Ports Collection, the emulator must be copied into the jail path specified in the binmiscctl command. Using the example above:

    mkdir $D/usr/local/bin
    cp /usr/local/bin/qemu-arm-static $D/usr/local/bin

Now the user can chroot into the environment normally, as root:

    chroot $D

SEE ALSO
lli(1), execve(2), jail(8)

HISTORY
The binmiscctl command was added in FreeBSD 10.1. It was developed to support the imgact_binmisc kernel module.

AUTHORS
Stacey D Son <sson@FreeBSD.org>