7 releases

0.4.1	Apr 1, 2024
0.4.0	Mar 29, 2024
0.3.17	Mar 2, 2024
0.3.16	~~Feb 27, 2024~~
0.3.12	Dec 4, 2023

#581 in Magic Beans

412 downloads per month

MIT license

265KB
6K SLoC

The IC Polyfill library

The project provides polyfill implementation of wasi_unstable and wasi_snapshot_preview1 functions using IC System API.

Usage

The intended use is to add this library as a dependency to your rust project. And then run wasi2ic on the produced Wasm binary.

In your project you would need to call the init function. It makes sure the linker does not remove the functions and can be used to initialize the random seed and define some environment variables.

Example:

    init(&[12,3,54,1], &[("PATH", "/usr/bin"), ("UID", "1028"), ("HOME", "/home/user")]);

Supported WASI functions (wasi_unstable, wasi_snapshot_preview1)

Status	Description
Supported	Function is fully supported.
No-op	Empty implementation that does nothing but can be called without issues.
Not implemented	Function is not yet implemented - calling it causes the application to panic.
Not supported	Function is not planned to be implemented - calling it causes the application to panic.

WASI function	Status
`args_get`	No-op
`args_sizes_get`	No-op
`clock_res_get`	Supported
`clock_time_get`	Supported
`environ_get`	Supported
`environ_sizes_get`	Supported
`fd_advise`	No-op
`fd_allocate`	No-op
`fd_close`	Supported
`fd_datasync`	No-op
`fd_fdstat_get`	Supported
`fd_fdstat_set_flags`	Supported
`fd_fdstat_set_rights`	Supported
`fd_filestat_get`	Supported
`fd_filestat_set_size`	No-op
`fd_filestat_set_times`	Supported
`fd_pread`	Supported
`fd_prestat_dir_name`	Supported
`fd_prestat_get`	Supported
`fd_pwrite`	Supported
`fd_read`	Supported
`fd_readdir`	Supported
`fd_renumber`	Supported
`fd_seek`	Supported
`fd_sync`	Supported
`fd_tell`	Supported
`fd_write`	Supported
`path_create_directory`	Supported
`path_filestat_get`	Supported¹
`path_filestat_set_times`	Supported¹
`path_link`	Supported¹
`path_open`	Supported¹
`path_readlink`	Not implemented
`path_remove_directory`	Supported
`path_rename`	Supported
`path_symlink`	Not implemented
`path_unlink_file`	Supported
`poll_oneoff`	Not implemented
`proc_exit`	Supported
`proc_raise`	Not implemented
`random_get`	Supported²
`sched_yield`	No-op
`sock_accept`	Not supported
`sock_recv`	Not supported
`sock_send`	Not supported
`sock_shutdown`	Not supported

¹ - Currently symlinks are not supported by the file system, this affects a few path_ functions, the flags ("follow symlink") parameter is currently ignored.

² - The random_get function utilizes a synchronous pseudo-random number generator.

Additional library functions

Function	Description
`init(seed: &[u8], env_pairs: &[(&str, &str)])`	Initialization call.
`raw_init(seed: *const u8, len: usize)`	Similar to `init`, but has simpler parameters for calling from C or C++.
`init_seed(seed: &[u8])`	Convenience method to explicitly re-initialize the random seed.
`raw_init_seed(seed: *const u8, len: usize)`	Similar to `init_seed`, but has simpler parameters for calling from C or C++.

Project features

The polyfill library's behavior can be configured using the following Cargo features:

transient use the transient file system implementation. This works faster but does not take the advantage of keeping the file system's state in stable memory (and the ability to keep FS state between canister upgrades).
report_wasi_calls outputs statistical information of the called polyfill functions.
skip_unimplemented_functions rather than throw exception on calling the unimplemented function, its implementation will be missing in the compilation. This can be useful if you want to provide custom implementations for those functions.

Dependencies

~2.5–3.5MB
~72K SLoC