# Fuchsia support

For information about checking out and building Fuchsia see
[Getting Started](https://fuchsia.googlesource.com/docs/+/master/getting_started.md)
and [Soure Code](https://fuchsia.googlesource.com/docs/+/master/development/source_code/README.md).
Image needs to be configured with sshd support:
```
fx set x64 --packages garnet/packages/products/sshd
fx full-build
```

You need to build fuchsia for both arm64 and amd64:

```
fx set arm64 --packages garnet/packages/products/sshd
fx full-build
```

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/zircon/+/HEAD/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 with the commands below.

Once you updated the syscalls definitions, everything can be regenerated by running:

```
make extract TARGETOS=fuchsia SOURCEDIR=/path/to/fuchsia/checkout
make generate
```

To build binaries:
```
make TARGETOS=fuchsia TARGETARCH=amd64 SOURCEDIR=/path/to/fuchsia/checkout
```

Run `syz-manager` with a config along the lines of:
```
{
	"name": "fuchsia",
	"target": "fuchsia/amd64",
	"http": ":12345",
	"workdir": "/workdir.fuchsia",
	"kernel_obj": "/fuchsia/out/build-zircon/build-x64",
	"syzkaller": "/syzkaller",
	"image": "/fuchsia/out/x64/out/build/images/fvm.blk",
	"sshkey": "/fuchsia/out/x64/ssh-keys/id_ed25519",
	"reproduce": false,
	"cover": false,
	"procs": 8,
	"type": "qemu",
	"vm": {
		"count": 10,
		"cpu": 4,
		"mem": 2048,
		"kernel": "/fuchsia/out/build-zircon/build-x64/zircon.bin",
		"initrd": "/fuchsia/out/x64/bootdata-blob.bin"
	}
}
```


## How to generate syscall description for FIDL

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
/fuchsia/out/x64/host_x64/fidlc --json /tmp/io.json --files /fuchsia/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
/fuchsia/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:

- Go 1.10 toolchain (in `/go1.10` dir in the example below)
- 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,
	"goroot": "/go1.10",
	"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
```