wasm-micro-runtime/samples/file/README.md

# "file" sample introduction

This sample demonstrates the supported file interaction API of WASI.
This sample can also demonstrate the SGX IPFS (Intel Protected File System), enabling an enclave to seal and unseal data at rest.

## Preparation

Please install WASI SDK, download the [wasi-sdk release](https://github.com/CraneStation/wasi-sdk/releases) and extract the archive to default path `/opt/wasi-sdk`.
For testing with SGX IPFS, follow the instructions in [the documentation of SGX for WAMR](../../doc/linux_sgx.md#sgx-intel-protected-file-system).

## Build the sample

```bash
mkdir build
cd build
cmake ..
make
```

The WebAssembly application is the file located at `wasm-app/file.wasm`.

## Run workload

Either use [iwasm-sample](../../product-mini/platforms/linux/) for Linux, or [enclave-sample](../../product-mini/platforms/linux-sgx/enclave-sample/) for Intel SGX to run the sample, with the argument to allow the file system interaction with the current folder (`--dir=.`).

The output with Linux and POSIX is like:

```bash
Opening a file..
[Test] File opening passed.
Writing to the file..
[Test] File writing passed.
Moving the cursor to the start of the file..
Reading from the file, up to 1000 characters..
Text read: Hello, world!
[Test] File reading passed.
Determine whether we reach the end of the file..
Is the end of file? 1
[Test] End of file detection passed.
Getting the plaintext size..
The plaintext size is 13.
[Test] Retrieving file offset passed.
Force actual write of all the cached data to the disk..
[Test] Retrieving file offset passed.
Writing 5 characters at offset 7..
File current offset: 13
[Test] Writing at specified offset passed.
Reading 5 characters at offset 7..
Text read: James
File current offset: 13
[Test] Reading at specified offset passed.
Allocate more space to the file..
File current offset: 13
Moving to the end..
File current offset: 23
[Test] Allocation or more space passed.
Extend the file size of 10 bytes using ftruncate..
File current offset: 23
Moving to the end..
File current offset: 33
[Test] Extension of the file size passed.
Closing from the file..
[Test] Closing file passed.
Getting the size of the file on disk..
The file size is 33.
All the tests passed!
```

The output with SGX and IPFS is like:

```bash
Opening a file..
[Test] File opening passed.
Writing to the file..
[Test] File writing passed.
Moving the cursor to the start of the file..
Reading from the file, up to 1000 characters..
Text read: Hello, world!
[Test] File reading passed.
Determine whether we reach the end of the file..
Is the end of file? 1
[Test] End of file detection passed.
Getting the plaintext size..
The plaintext size is 13.
[Test] Retrieving file offset passed.
Force actual write of all the cached data to the disk..
[Test] Retrieving file offset passed.
Writing 5 characters at offset 7..
File current offset: 13
[Test] Writing at specified offset passed.
Reading 5 characters at offset 7..
Text read: James
File current offset: 13
[Test] Reading at specified offset passed.
Allocate more space to the file..
File current offset: 23
Moving to the end..
File current offset: 23
[Test] Allocation or more space passed.
Extend the file size of 10 bytes using ftruncate..
File current offset: 23
Moving to the end..
File current offset: 33
[Test] Extension of the file size passed.
Closing from the file..
[Test] Closing file passed.
Getting the size of the file on disk..
The file size is 4096.
All the tests passed!
```

For SGX IPFS, refer to [SGX Intel Protected File System](../../doc/linux_sgx.md#sgx-intel-protected-file-system) for more details.
linux-sgx: Implement SGX IPFS as POSIX backend for file interaction (#1489) This PR integrates an Intel SGX feature called Intel Protection File System Library (IPFS) into the runtime to create, operate and delete files inside the enclave, while guaranteeing the confidentiality and integrity of the data persisted. IPFS can be referred to here: https://www.intel.com/content/www/us/en/developer/articles/technical/overview-of-intel-protected-file-system-library-using-software-guard-extensions.html Introduce a cmake variable `WAMR_BUILD_SGX_IPFS`, when enabled, the files interaction API of WASI will leverage IPFS, instead of the regular POSIX OCALLs. The implementation has been written with light changes to sgx platform layer, so all the security aspects WAMR relies on are conserved. In addition to this integration, the following changes have been made: - The CI workflow has been adapted to test the compilation of the runtime and sample with the flag `WAMR_BUILD_SGX_IPFS` set to true - Introduction of a new sample that demonstrates the interaction of the files (called `file`), - Documentation of this new feature 2022-09-28 05:09:58 +00:00			`# "file" sample introduction`

			`This sample demonstrates the supported file interaction API of WASI.`
			`This sample can also demonstrate the SGX IPFS (Intel Protected File System), enabling an enclave to seal and unseal data at rest.`

			`## Preparation`

			Please install WASI SDK, download the [wasi-sdk release](https://github.com/CraneStation/wasi-sdk/releases) and extract the archive to default path `/opt/wasi-sdk`.
			`For testing with SGX IPFS, follow the instructions in [the documentation of SGX for WAMR](../../doc/linux_sgx.md#sgx-intel-protected-file-system).`

			`## Build the sample`

			```bash
			`mkdir build`
			`cd build`
			`cmake ..`
			`make`
			```

			The WebAssembly application is the file located at `wasm-app/file.wasm`.

			`## Run workload`

			Either use [iwasm-sample](../../product-mini/platforms/linux/) for Linux, or [enclave-sample](../../product-mini/platforms/linux-sgx/enclave-sample/) for Intel SGX to run the sample, with the argument to allow the file system interaction with the current folder (`--dir=.`).

			`The output with Linux and POSIX is like:`

			```bash
			`Opening a file..`
			`[Test] File opening passed.`
			`Writing to the file..`
			`[Test] File writing passed.`
			`Moving the cursor to the start of the file..`
			`Reading from the file, up to 1000 characters..`
			`Text read: Hello, world!`
			`[Test] File reading passed.`
			`Determine whether we reach the end of the file..`
			`Is the end of file? 1`
			`[Test] End of file detection passed.`
			`Getting the plaintext size..`
			`The plaintext size is 13.`
			`[Test] Retrieving file offset passed.`
			`Force actual write of all the cached data to the disk..`
			`[Test] Retrieving file offset passed.`
			`Writing 5 characters at offset 7..`
			`File current offset: 13`
			`[Test] Writing at specified offset passed.`
			`Reading 5 characters at offset 7..`
			`Text read: James`
			`File current offset: 13`
			`[Test] Reading at specified offset passed.`
			`Allocate more space to the file..`
			`File current offset: 13`
			`Moving to the end..`
			`File current offset: 23`
			`[Test] Allocation or more space passed.`
			`Extend the file size of 10 bytes using ftruncate..`
			`File current offset: 23`
			`Moving to the end..`
			`File current offset: 33`
			`[Test] Extension of the file size passed.`
			`Closing from the file..`
			`[Test] Closing file passed.`
			`Getting the size of the file on disk..`
			`The file size is 33.`
			`All the tests passed!`
			```

			`The output with SGX and IPFS is like:`

			```bash
			`Opening a file..`
			`[Test] File opening passed.`
			`Writing to the file..`
			`[Test] File writing passed.`
			`Moving the cursor to the start of the file..`
			`Reading from the file, up to 1000 characters..`
			`Text read: Hello, world!`
			`[Test] File reading passed.`
			`Determine whether we reach the end of the file..`
			`Is the end of file? 1`
			`[Test] End of file detection passed.`
			`Getting the plaintext size..`
			`The plaintext size is 13.`
			`[Test] Retrieving file offset passed.`
			`Force actual write of all the cached data to the disk..`
			`[Test] Retrieving file offset passed.`
			`Writing 5 characters at offset 7..`
			`File current offset: 13`
			`[Test] Writing at specified offset passed.`
			`Reading 5 characters at offset 7..`
			`Text read: James`
			`File current offset: 13`
			`[Test] Reading at specified offset passed.`
			`Allocate more space to the file..`
			`File current offset: 23`
			`Moving to the end..`
			`File current offset: 23`
			`[Test] Allocation or more space passed.`
			`Extend the file size of 10 bytes using ftruncate..`
			`File current offset: 23`
			`Moving to the end..`
			`File current offset: 33`
			`[Test] Extension of the file size passed.`
			`Closing from the file..`
			`[Test] Closing file passed.`
			`Getting the size of the file on disk..`
			`The file size is 4096.`
			`All the tests passed!`
			```

			`For SGX IPFS, refer to [SGX Intel Protected File System](../../doc/linux_sgx.md#sgx-intel-protected-file-system) for more details.`