About

This directory contains the necessary components to run Non-SFI NaCl nexes (native executables) from within Mojo.

Using

The Non-SFI NaCl and accompanying tests should be built by default for Linux. The boolean indicating if they are built is “mojo_use_nacl_nonsfi”, defined inside the BUILD files.

Building Non-SFI NaCl

Build Mojo (all following commands assume you are in the root of the mojo repository):

$  ./mojo/tools/mojob.py gn
$  ./mojo/tools/mojob.py build

Doing this build step will automatically create the necessary content handlers and pexes.

Translating and Running Pexes

When portable executable files (pexes) are generated by mojo, they are created as .pexe.mojo files. These pexes are generated by building a gn target with the mojo_native_application template with a PNaCl toolchain.

The “pexe” part of the name comes from the fact that they are portable, and the “mojo” part of the name comes from the fact that they have the line #!mojo mojo:content_handler_nonsfi_pexe prepended to them, so the appropriate pexe content handler can be found by the Mojo Shell.

To run the FOOBAR.pexe.mojo pexe (aka, to translate and execute it), run the following:

$ ./out/Debug/mojo_shell --enable-multiprocess ./out/Debug/FOOBAR.pexe.mojo

or, alternatively, for a version compatible with Android:

$  ./mojo/devtools/common/mojo_run --enable-multiprocess mojo:FOOBAR.pexe
[--android]

For more information on the process of translating and handling nexes and pexes, refer to the services/nacl directory.

Manually Translating Pexes and Running Nexes

A raw pexe of unit tests will be built, at ./out/Debug/newlib_pnacl/monacl_test.pexe. To manually translate this pexe into a non-SFI nexe:

$ ./native_client/toolchain/linux_x86/pnacl_newlib/bin/pnacl-translate \
./out/Debug/newlib_pnacl/FOOBAR.pexe -o FOOBAR.nexe -arch x86-32-nonsfi

Now, you should have the fully translated nexe (called FOOBAR.nexe). You can run the nexe through the monacl shell (a minimal, “nexe-only” shell, which loads the nexe ELF file -- see monacl_shell_nonsfi.cc):

$ ./out/Debug/clang_x86/monacl_shell_nonsfi FOOBAR.nexe

This monacl_shell_nonsfi is the easiest way to run nexes in Mojo -- however, it is not the only way. Usually, applications are launched through the “mojo_shell”, but some additional information is required to know how to handle this content (i.e., how does the mojo_shell know it is dealing with a nonsfi nexe?).

The BUILD.gn files in Mojo automatically make the “monacl_test” pexe, translate it to a nexe, and prepend a line (#!mojo mojo:content_handler_nonsfi_nexe) to the front of the file, at which point it is also runnable through the mojo_shell. These files, which start with this “#!” line, are “.mojo” files. The nexes can be run like this:

$  ./out/Debug/mojo_shell --enable-multiprocess out/Debug/FOOBAR.mojo