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# Fuchsia support
For information about checking out and building Fuchsia see
[Getting Started](https://fuchsia.dev/fuchsia-src/get-started)
and [Source Code](https://fuchsia.dev/fuchsia-src/get-started/get_fuchsia_source).
## Prerequisites
To run syzkaller with a fuchsia target, you will need:
* A fuchsia checkout.
The rest of the document will use the following environment variables:
* `SOURCEDIR` path of your fuchsia checkout.
## Building Fuchsia
To build fuchsia run:
```shell
$ fx --dir "out/arm64" set core.arm64 \
--with-base "//bundles:tools" \
--with-base "//src/testing/fuzzing/syzkaller" \
--args=syzkaller_dir='"/full/path/to/syzkaller"'
$ fx clean-build
```
And
```shell
$ fx --dir "out/x64" set core.x64 \
--with-base "//bundles:tools" \
--with-base "//src/testing/fuzzing/syzkaller" \
--args=syzkaller_dir='"/full/path/to/syzkaller"'
$ fx clean-build
```
## Building binaries for fuchsia
To build all the binaries required for running syzkaller in fuchsia, run:
```
$ make TARGETOS=fuchsia TARGETARCH=amd64 \
SOURCEDIR=path/to/fuchsia/checkout
```
## Running syz-manager
Running syz-manager requires you to have built fuchsia previously, and added the ssh keys to the fuchsia.zbi image:
```
$ ${SOURCEDIR}/out/x64/host_x64/zbi -o ${SOURCEDIR}/out/x64/fuchsia-ssh.zbi ${SOURCEDIR}/out/x64/fuchsia.zbi --entry "data/ssh/authorized_keys=${SOURCEDIR}/.ssh/authorized_keys"
```
You will also need to extend the `fvm` image:
```
$ cp "${SOURCEDIR}/out/x64/obj/build/images/fvm.blk" "${SOURCEDIR}/out/x64/obj/build/images/fvm-extended.blk"
$ ${SOURCEDIR}/out/x64/host_x64/fvm "${SOURCEDIR}/out/x64/obj/build/images/fvm-extended.blk" extend --length 3G
```
Note: This needs to be repeated after each `fx build`.
Run `syz-manager` with a config along the lines of:
```
{
"name": "fuchsia",
"target": "fuchsia/amd64",
"http": ":12345",
"workdir": "/workdir.fuchsia",
"kernel_obj": "/fuchsia/out/x64.zircon/kernel-x64-gcc",
"syzkaller": "/syzkaller",
"image": "/fuchsia/out/x64/obj/build/images/fvm-extended.blk",
"sshkey": "/fuchsia/.ssh/pkey",
"reproduce": false,
"cover": false,
"procs": 8,
"type": "qemu",
"vm": {
"count": 10,
"cpu": 4,
"mem": 2048,
"kernel": "/fuchsia/out/x64/multiboot.bin",
"initrd": "/fuchsia/out/x64/fuchsia-ssh.zbi"
}
}
```
## Update syscall and fidl definitions
Syscall descriptions live in the `sys/fuchsia` folder. To update a syscall, you need to modify the `.txt` file that contains it, make sure your new definition matches the one in zircon's [syscalls.abigen](https://fuchsia.googlesource.com/fuchsia/+/master/zircon/system/public/zircon/syscalls.abigen) file. **If the syscall was used in `executor/common_fuchsia.h`, you need to update the usages there as well**. FIDL definitions do not need manual updating because they are extracted automatically when you run `make extract`, but they require Fuchsia to be rebuilt for each architecture (see "Building Fuchsia" above).
Once you updated the syscalls definitions, everything can be regenerated by running:
```
make extract TARGETOS=fuchsia SOURCEDIR=/path/to/fuchsia/checkout
make generate
```
## How to generate syscall description for FIDL
TODO: This section is out of date.
Syscall descriptions for FIDL are automatically generated as part of `make extract` as described above.
However, if you wish to manually generate syscall descriptions for a given `.fidl` file, do the following.
FIDL files should first be compiled into FIDL intermediate representation (JSON) files using `fidlc`:
```bash
$SOURCEDIR/out/x64/host_x64/fidlc --json /tmp/io.json --files $SOURCEDIR/zircon/system/fidl/fuchsia-io/io.fidl
```
Then run FIDL compiler backend `fidlgen` with syzkaller generator, which compiles a FIDL IR file into a syscall description file:
```bash
$SOURCEDIR/out/x64/host_x64/fidlgen -generators syzkaller -json /tmp/io.json -output-base fidl_io -include-base fidl_io
```
## Running syz-ci locally
To run `syz-ci` locally for Fuchsia, you need:
- bootstrapped Fuchsia checkout (in `/bootstrap/fuchsia` dir in the example below)
- bootstrap `syz-ci` binary (in the current dir, build with `make ci`)
- `syz-ci` config similar to the one below (in `ci.cfg` file in the current dir)
```
{
"name": "testci",
"http": ":50000",
"manager_port_start": 50001,
"syzkaller_repo": "https://github.com/google/syzkaller.git",
"managers": [
{
"name": "fuchsia",
"repo": "https://fuchsia.googlesource.com",
"manager_config": {
"target": "fuchsia/amd64",
"type": "qemu",
"cover": false,
"procs": 8,
"vm": {
"count": 4,
"cpu": 4,
"mem": 1024
}
}
}
]
}
```
Run `syz-ci` as:
```
SOURCEDIR=/bootstrap/fuchsia ./syz-ci -config ci.cfg
```
## Troubleshooting
While running the `make extract` step, it's possible that the fidl definitions
are not up to date. It could happen that they have been removed or renamed.
If this is the case, you would see an error mentioning that the fidl.json file
could not be found:
```
go generate ./sys/fuchsia
cannot find /path-to-fuchsia/out/x64/fidling/gen/zircon/public/fidl/zircon-ethernet/zircon-ethernet.fidl.json
exit status 1
```
You can search for the string in the fuchsia repos or in the code-review tool to
see what happened to it. If the fidl interface was renamed or removed, you
should update `sys/fuchsia/fidlgen/main.go` to reflect this change, and remove the
stale autogenerated files.
|
