uvwasi
implements the WASI system call API, so that WebAssembly
runtimes can easily implement WASI calls. Under the hood, uvwasi
leverages libuv where possible for maximum portability.
|
WebAssembly code | WebAssembly application code
| |
| v
| WASI syscalls (inserted by compiler toolchain)
| |
------------------------------+ |
| v
WebAssembly runtime (Node.js) | uvwasi (implementation of WASI)
| |
| v
| libuv
| |
| v
| platform-specific calls
|
(Hence uvwasi isn't for making C-programs-that-use-libuv-APIs execute on WASI runtimes. That would either be a new platform added by libuv, or done through POSIX emulation by the Emscripten or wasi-sdk toolchains.)
To build with CMake:
$ mkdir -p out/cmake ; cd out/cmake # create build directory
$ cmake ../.. -DBUILD_TESTING=ON # generate project with test
$ cmake --build . # build
$ ctest -C Debug --output-on-failure # run tests
#include <stdlib.h>
#include <assert.h>
#include "uv.h"
#include "uvwasi.h"
int main(void) {
uvwasi_t uvwasi;
uvwasi_options_t init_options;
uvwasi_errno_t err;
/* Setup the initialization options. */
init_options.in = 0;
init_options.out = 1;
init_options.err = 2;
init_options.fd_table_size = 3;
init_options.argc = 3;
init_options.argv = calloc(3, sizeof(char*));
init_options.argv[0] = "--foo=bar";
init_options.argv[1] = "-baz";
init_options.argv[2] = "100";
init_options.envp = NULL;
init_options.preopenc = 1;
init_options.preopens = calloc(1, sizeof(uvwasi_preopen_t));
init_options.preopens[0].mapped_path = "/var";
init_options.preopens[0].real_path = ".";
init_options.allocator = NULL;
/* Initialize the sandbox. */
err = uvwasi_init(&uvwasi, &init_options);
assert(err == UVWASI_ESUCCESS);
/* TODO(cjihrig): Show an example system call or two. */
/* Clean up resources. */
uvwasi_destroy(&uvwasi);
return 0;
}
The WASI API is versioned. This documentation is based on snapshot_1.
uvwasi
implements the WASI system call API with the following
additions/modifications:
- Each system call takes an additional
uvwasi_t*
as its first argument. Theuvwasi_t
is the sandbox under which system calls are issued. Eachuvwasi_t
can have different command line arguments, environment variables, preopened directories, file descriptor mappings, etc. This allows one controlling process to host multiple WASI applications simultaneously. - Each system call returns a
uvwasi_errno_t
. This appears to be expected of WASI system calls, but it is not explicitly part of the official API docs. This detail is explicitly documented here. - Additional functions and data types are provided for interacting with WASI
sandboxes and the
uvwasi
library. These APIs are documented in the Unofficial APIs section below.
This section contains data types and functions for working with uvwasi
. They
are not part of the official WASI API, but are used to embed uvwasi
.
The major release version of the uvwasi
library. uvwasi
follows semantic
versioning. Changes to this value represent breaking changes in the public API.
The minor release version of the uvwasi
library. uvwasi
follows semantic
versioning. Changes to this value represent feature additions in the public API.
The patch release version of the uvwasi
library. uvwasi
follows semantic
versioning. Changes to this value represent bug fixes in the public API.
The major, minor, and patch versions of the uvwasi
library encoded as a single
integer value.
The major, minor, and patch versions of the uvwasi
library encoded as a
version string.
The version of the WASI API targeted by uvwasi
.
An individual WASI sandbox instance.
typedef struct uvwasi_s {
struct uvwasi_fd_table_t fds;
uvwasi_size_t argc;
char** argv;
char* argv_buf;
uvwasi_size_t argv_buf_size;
uvwasi_size_t envc;
char** env;
char* env_buf;
uvwasi_size_t env_buf_size;
} uvwasi_t;
A data structure used to map a directory path within a WASI sandbox to a directory path on the WASI host platform.
typedef struct uvwasi_preopen_s {
char* mapped_path;
char* real_path;
} uvwasi_preopen_t;
A data structure used to pass configuration options to uvwasi_init()
.
typedef struct uvwasi_options_s {
uvwasi_size_t fd_table_size;
uvwasi_size_t preopenc;
uvwasi_preopen_t* preopens;
uvwasi_size_t argc;
char** argv;
char** envp;
uvwasi_fd_t in;
uvwasi_fd_t out;
uvwasi_fd_t err;
const uvwasi_mem_t* allocator;
} uvwasi_options_t;
Initializes a sandbox represented by a uvwasi_t
using the options represented
by a uvwasi_options_t
.
Inputs:
-
__wasi_t uvwasi
The sandbox to initialize.
-
__wasi_options_t options
Configuration options used when initializing the sandbox.
Outputs:
- None
Returns:
-
__wasi_errno_t errno
A WASI errno.
Cleans up resources related to a WASI sandbox. This function notably does not return an error code.
Inputs:
-
__wasi_t uvwasi
The sandbox to clean up.
Outputs:
- None
Returns:
- None
This section has been adapted from the official WASI API documentation.
uvwasi_args_get()
uvwasi_args_sizes_get()
uvwasi_clock_res_get()
uvwasi_clock_time_get()
uvwasi_environ_get()
uvwasi_environ_sizes_get()
uvwasi_fd_advise()
uvwasi_fd_allocate()
uvwasi_fd_close()
uvwasi_fd_datasync()
uvwasi_fd_fdstat_get()
uvwasi_fd_fdstat_set_flags()
uvwasi_fd_fdstat_set_rights()
uvwasi_fd_filestat_get()
uvwasi_fd_filestat_set_size()
uvwasi_fd_filestat_set_times()
uvwasi_fd_pread()
uvwasi_fd_prestat_get()
uvwasi_fd_prestat_dir_name()
uvwasi_fd_pwrite()
uvwasi_fd_read()
uvwasi_fd_readdir()
uvwasi_fd_renumber()
uvwasi_fd_seek()
uvwasi_fd_sync()
uvwasi_fd_tell()
uvwasi_fd_write()
uvwasi_path_create_directory()
uvwasi_path_filestat_get()
uvwasi_path_filestat_set_times()
uvwasi_path_link()
uvwasi_path_open()
uvwasi_path_readlink()
uvwasi_path_remove_directory()
uvwasi_path_rename()
uvwasi_path_symlink()
uvwasi_path_unlink_file()
uvwasi_poll_oneoff()
uvwasi_proc_exit()
uvwasi_proc_raise()
uvwasi_random_get()
uvwasi_sched_yield()
uvwasi_sock_recv()
uvwasi_sock_send()
uvwasi_sock_shutdown()
Read command-line argument data.
The sizes of the buffers should match that returned by uvwasi_args_sizes_get()
.
Inputs:
-
A pointer to a buffer to write the argument pointers.
-
A pointer to a buffer to write the argument string data.
Return command-line argument data sizes.
Outputs:
-
The number of arguments.
-
The size of the argument string data.
Return the resolution of a clock.
Implementations are required to provide a non-zero value for supported clocks.
For unsupported clocks, return UVWASI_EINVAL
.
Note: This is similar to clock_getres
in POSIX.
Inputs:
-
__wasi_clockid_t clock_id
The clock for which to return the resolution.
Outputs:
-
__wasi_timestamp_t resolution
The resolution of the clock.
Return the time value of a clock.
Note: This is similar to clock_gettime
in POSIX.
Inputs:
-
__wasi_clockid_t clock_id
The clock for which to return the time.
-
__wasi_timestamp_t precision
The maximum lag (exclusive) that the returned time value may have, compared to its actual value.
Outputs:
-
__wasi_timestamp_t time
The time value of the clock.
Read environment variable data.
The sizes of the buffers should match that returned by uvwasi_environ_sizes_get()
.
Inputs:
-
A pointer to a buffer to write the environment variable pointers.
-
A pointer to a buffer to write the environment variable string data.
Return command-line argument data sizes.
Outputs:
-
The number of environment variables.
-
__wasi_size_t *environ_buf_size
The size of the environment variable string data.
Provide file advisory information on a file descriptor.
Note: This is similar to posix_fadvise
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor for the file for which to provide file advisory information.
-
__wasi_filesize_t offset
The offset within the file to which the advisory applies.
-
The length of the region to which the advisory applies.
-
__wasi_advice_t advice
The advice.
Force the allocation of space in a file.
Note: This is similar to posix_fallocate
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor for the file in which to allocate space.
-
__wasi_filesize_t offset
The offset at which to start the allocation.
-
The length of the area that is allocated.
Close a file descriptor.
Note: This is similar to close
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to close.
Synchronize the data of a file to disk.
Note: This is similar to fdatasync
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor of the file to synchronize to disk.
Get the attributes of a file descriptor.
Note: This returns similar flags to fsync(fd, F_GETFL)
in POSIX, as well
as additional fields.
Inputs:
-
__wasi_fd_t fd
The file descriptor to inspect.
-
__wasi_fdstat_t *buf
The buffer where the file descriptor's attributes are stored.
Adjust the flags associated with a file descriptor.
Note: This is similar to fcntl(fd, F_SETFL, flags)
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to operate on.
-
__wasi_fdflags_t flags
The desired values of the file descriptor flags.
Adjust the rights associated with a file descriptor.
This can only be used to remove rights, and returns
UVWASI_ENOTCAPABLE
if called in a way that would attempt
to add rights.
Inputs:
-
__wasi_fd_t fd
The file descriptor to operate on.
-
__wasi_rights_t fs_rights_base
and__wasi_rights_t fs_rights_inheriting
The desired rights of the file descriptor.
Return the attributes of an open file.
Inputs:
-
__wasi_fd_t fd
The file descriptor to inspect.
-
__wasi_filestat_t *buf
The buffer where the file's attributes are stored.
Adjust the size of an open file. If this increases the file's size, the extra bytes are filled with zeros.
Note: This is similar to ftruncate
in POSIX.
Inputs:
-
__wasi_fd_t fd
A file descriptor for the file to adjust.
-
__wasi_filesize_t st_size
The desired file size.
Adjust the timestamps of an open file or directory.
Note: This is similar to futimens
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to operate on.
-
__wasi_timestamp_t st_atim
The desired values of the data access timestamp.
-
__wasi_timestamp_t st_mtim
The desired values of the data modification timestamp.
-
__wasi_fstflags_t fst_flags
A bitmask indicating which timestamps to adjust.
Read from a file descriptor, without using and updating the file descriptor's offset.
Note: This is similar to preadv
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor from which to read data.
-
const __wasi_iovec_t *iovs
and__wasi_size_t iovs_len
List of scatter/gather vectors in which to store data.
-
__wasi_filesize_t offset
The offset within the file at which to read.
Outputs:
Return a description of the given preopened file descriptor.
Inputs:
-
__wasi_fd_t fd
The file descriptor about which to retrieve information.
-
__wasi_prestat_t *buf
The buffer where the description is stored.
Return a description of the given preopened file descriptor.
Inputs:
-
__wasi_fd_t fd
The file descriptor about which to retrieve information.
-
const char *path
and__wasi_size_t path_len
A buffer into which to write the preopened directory name.
Write to a file descriptor, without using and updating the file descriptor's offset.
Note: This is similar to pwritev
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to which to write data.
-
const __wasi_ciovec_t *iovs
and__wasi_size_t iovs_len
List of scatter/gather vectors from which to retrieve data.
-
__wasi_filesize_t offset
The offset within the file at which to write.
Outputs:
Read from a file descriptor.
Note: This is similar to readv
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor from which to read data.
-
const __wasi_iovec_t *iovs
and__wasi_size_t iovs_len
List of scatter/gather vectors to which to store data.
Outputs:
Read directory entries from a directory.
When successful, the contents of the output buffer consist of
a sequence of directory entries. Each directory entry consists
of a uvwasi_dirent_t
object, followed by uvwasi_dirent_t::d_namlen
bytes
holding the name of the directory entry.
This function fills the output buffer as much as possible, potentially truncating the last directory entry. This allows the caller to grow its read buffer size in case it's too small to fit a single large directory entry, or skip the oversized directory entry.
Inputs:
-
__wasi_fd_t fd
The directory from which to read the directory entries.
-
void *buf
and__wasi_size_t buf_len
The buffer where directory entries are stored.
-
__wasi_dircookie_t cookie
The location within the directory to start reading.
Outputs:
-
The number of bytes stored in the read buffer. If less than the size of the read buffer, the end of the directory has been reached.
Atomically replace a file descriptor by renumbering another file descriptor.
Due to the strong focus on thread safety, this environment does not provide a mechanism to duplicate or renumber a file descriptor to an arbitrary number, like dup2(). This would be prone to race conditions, as an actual file descriptor with the same number could be allocated by a different thread at the same time.
This function provides a way to atomically renumber file descriptors, which would disappear if dup2() were to be removed entirely.
Inputs:
-
__wasi_fd_t from
The file descriptor to renumber.
-
__wasi_fd_t to
The file descriptor to overwrite.
Move the offset of a file descriptor.
Note: This is similar to lseek
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to operate on.
-
__wasi_filedelta_t offset
The number of bytes to move.
-
__wasi_whence_t whence
The base from which the offset is relative.
Outputs:
-
__wasi_filesize_t newoffset
The new offset of the file descriptor, relative to the start of the file.
Synchronize the data and metadata of a file to disk.
Note: This is similar to fsync
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor of the file containing the data and metadata to synchronize to disk.
Return the current offset of a file descriptor.
Note: This is similar to lseek(fd, 0, SEEK_CUR)
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to inspect.
Outputs:
-
__wasi_filesize_t offset
The current offset of the file descriptor, relative to the start of the file.
Write to a file descriptor.
Note: This is similar to writev
in POSIX.
Inputs:
-
__wasi_fd_t fd
The file descriptor to which to write data.
-
const __wasi_ciovec_t *iovs
and__wasi_size_t iovs_len
List of scatter/gather vectors from which to retrieve data.
Outputs:
Create a directory.
Note: This is similar to mkdirat
in POSIX.
Inputs:
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
const char *path
and__wasi_size_t path_len
The path at which to create the directory.
Return the attributes of a file or directory.
Note: This is similar to stat
in POSIX.
Inputs:
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
__wasi_lookupflags_t flags
Flags determining the method of how the path is resolved.
-
const char *path
and__wasi_size_t path_len
The path of the file or directory to inspect.
-
__wasi_filestat_t *buf
The buffer where the file's attributes are stored.
Adjust the timestamps of a file or directory.
Note: This is similar to utimensat
in POSIX.
Inputs:
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
__wasi_lookupflags_t flags
Flags determining the method of how the path is resolved.
-
const char *path
and__wasi_size_t path_len
The path of the file or directory to operate on.
-
__wasi_timestamp_t st_atim
The desired values of the data access timestamp.
-
__wasi_timestamp_t st_mtim
The desired values of the data modification timestamp.
-
__wasi_fstflags_t fst_flags
A bitmask indicating which timestamps to adjust.
Create a hard link.
Note: This is similar to linkat
in POSIX.
Inputs:
-
__wasi_fd_t old_fd
The working directory at which the resolution of the old path starts.
-
__wasi_lookupflags_t old_flags
Flags determining the method of how the path is resolved.
-
const char *old_path
and__wasi_size_t old_path_len
The source path from which to link.
-
__wasi_fd_t new_fd
The working directory at which the resolution of the new path starts.
-
const char *new_path
and__wasi_size_t new_path_len
The destination path at which to create the hard link.
Open a file or directory.
The returned file descriptor is not guaranteed to be the lowest-numbered file descriptor not currently open; it is randomized to prevent applications from depending on making assumptions about indexes, since this is error-prone in multi-threaded contexts. The returned file descriptor is guaranteed to be less than 231.
Note: This is similar to openat
in POSIX.
Inputs:
-
__wasi_fd_t dirfd
The working directory at which the resolution of the path starts.
-
__wasi_lookupflags_t dirflags
Flags determining the method of how the path is resolved.
-
const char *path
and__wasi_size_t path_len
The relative path of the file or directory to open, relative to the
dirfd
directory. -
__wasi_oflags_t o_flags
The method by which to open the file.
-
__wasi_rights_t fs_rights_base
and__wasi_rights_t fs_rights_inheriting
The initial rights of the newly created file descriptor. The implementation is allowed to return a file descriptor with fewer rights than specified, if and only if those rights do not apply to the type of file being opened.
The base rights are rights that will apply to operations using the file descriptor itself, while the inheriting rights are rights that apply to file descriptors derived from it.
-
__wasi_fdflags_t fs_flags
The initial flags of the file descriptor.
Outputs:
-
__wasi_fd_t fd
The file descriptor of the file that has been opened.
Read the contents of a symbolic link.
Note: This is similar to readlinkat
in POSIX.
Inputs:
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
const char *path
and__wasi_size_t path_len
The path of the symbolic link from which to read.
-
char *buf
and__wasi_size_t buf_len
The buffer to which to write the contents of the symbolic link.
Outputs:
Remove a directory.
Return UVWASI_ENOTEMPTY
if the directory is not empty.
Note: This is similar to unlinkat(fd, path, AT_REMOVEDIR)
in POSIX.
Inputs:
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
const char *path
and__wasi_size_t path_len
The path to a directory to remove.
Rename a file or directory.
Note: This is similar to renameat
in POSIX.
Inputs:
-
__wasi_fd_t old_fd
The working directory at which the resolution of the old path starts.
-
const char *old_path
and__wasi_size_t old_path_len
The source path of the file or directory to rename.
-
__wasi_fd_t new_fd
The working directory at which the resolution of the new path starts.
-
const char *new_path
and__wasi_size_t new_path_len
The destination path to which to rename the file or directory.
Create a symbolic link.
Note: This is similar to symlinkat
in POSIX.
Inputs:
-
const char *old_path
and__wasi_size_t old_path_len
The contents of the symbolic link.
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
const char *new_path
and__wasi_size_t new_path_len
The destination path at which to create the symbolic link.
Unlink a file.
Return UVWASI_EISDIR
if the path refers to a directory.
Note: This is similar to unlinkat(fd, path, 0)
in POSIX.
Inputs:
-
__wasi_fd_t fd
The working directory at which the resolution of the path starts.
-
const char *path
and__wasi_size_t path_len
The path to a file to unlink.
Concurrently poll for the occurrence of a set of events.
Inputs:
-
const __wasi_subscription_t *in
The events to which to subscribe.
-
__wasi_event_t *out
The events that have occurred.
-
Both the number of subscriptions and events.
Outputs:
Terminate the process normally. An exit code of 0 indicates successful termination of the program. The meanings of other values is dependent on the environment.
Note: This is similar to _Exit
in POSIX.
Inputs:
-
__wasi_exitcode_t rval
The exit code returned by the process.
Does not return.
Send a signal to the process of the calling thread.
Note: This is similar to raise
in POSIX.
Inputs:
-
__wasi_signal_t sig
The signal condition to trigger.
Write high-quality random data into a buffer.
This function blocks when the implementation is unable to immediately provide sufficient high-quality random data.
This function may execute slowly, so when large mounts of random data are required, it's advisable to use this function to seed a pseudo-random number generator, rather than to provide the random data directly.
Inputs:
Temporarily yield execution of the calling thread.
Note: This is similar to sched_yield
in POSIX.
Receive a message from a socket.
Note: This is similar to recv
in POSIX, though it also supports reading
the data into multiple buffers in the manner of readv
.
Inputs:
-
__wasi_fd_t sock
The socket on which to receive data.
-
const __wasi_iovec_t *ri_data
and__wasi_size_t ri_data_len
List of scatter/gather vectors to which to store data.
-
__wasi_riflags_t ri_flags
Message flags.
Outputs:
-
Number of bytes stored in
ri_data
. -
__wasi_roflags_t ro_flags
Message flags.
Send a message on a socket.
Note: This is similar to send
in POSIX, though it also supports writing
the data from multiple buffers in the manner of writev
.
Inputs:
-
__wasi_fd_t sock
The socket on which to send data.
-
const __wasi_ciovec_t *si_data
and__wasi_size_t si_data_len
List of scatter/gather vectors to which to retrieve data
-
__wasi_siflags_t si_flags
Message flags.
Outputs:
Shut down socket send and receive channels.
Note: This is similar to shutdown
in POSIX.
Inputs:
-
__wasi_fd_t sock
The socket on which to shutdown channels.
-
__wasi_sdflags_t how
Which channels on the socket to shut down.
File or memory access pattern advisory information.
Used by uvwasi_fd_advise()
.
Possible values:
-
The application expects that it will not access the specified data in the near future.
-
The application expects to access the specified data once and then not reuse it thereafter.
-
The application has no advice to give on its behavior with respect to the specified data.
-
The application expects to access the specified data in a random order.
-
The application expects to access the specified data sequentially from lower offsets to higher offsets.
-
The application expects to access the specified data in the near future.
A region of memory for scatter/gather writes.
Used by uvwasi_fd_pwrite()
, uvwasi_fd_write()
, and uvwasi_sock_send()
.
Members:
Identifiers for clocks.
Used by uvwasi_subscription_t
, uvwasi_clock_res_get()
, and uvwasi_clock_time_get()
.
Possible values:
-
The store-wide monotonic clock, which is defined as a clock measuring real time, whose value cannot be adjusted and which cannot have negative clock jumps.
The epoch of this clock is undefined. The absolute time value of this clock therefore has no meaning.
-
UVWASI_CLOCK_PROCESS_CPUTIME_ID
The CPU-time clock associated with the current process.
-
The clock measuring real time. Time value zero corresponds with 1970-01-01T00:00:00Z.
-
UVWASI_CLOCK_THREAD_CPUTIME_ID
The CPU-time clock associated with the current thread.
Identifier for a device containing a file system. Can be used
in combination with uvwasi_inode_t
to uniquely identify a file or
directory in the filesystem.
Used by uvwasi_filestat_t
.
A reference to the offset of a directory entry.
Used by uvwasi_dirent_t
and uvwasi_fd_readdir()
.
Special values:
A directory entry.
Members:
-
__wasi_dircookie_t d_next
The offset of the next directory entry stored in this directory.
-
__wasi_inode_t d_ino
The serial number of the file referred to by this directory entry.
-
The length of the name of the directory entry.
-
__wasi_filetype_t d_type
The type of the file referred to by this directory entry.
Error codes returned by functions.
Not all of these error codes are returned by the functions provided by this API; some are used in higher-level library layers, and others are provided merely for alignment with POSIX.
Used by uvwasi_event_t
.
Possible values:
-
No error occurred. System call completed successfully.
-
Argument list too long.
-
Permission denied.
-
Address in use.
-
Address not available.
-
Address family not supported.
-
Resource unavailable, or operation would block.
-
Connection already in progress.
-
Bad file descriptor.
-
Bad message.
-
Device or resource busy.
-
Operation canceled.
-
No child processes.
-
Connection aborted.
-
Connection refused.
-
Connection reset.
-
Resource deadlock would occur.
-
Destination address required.
-
Mathematics argument out of domain of function.
-
Reserved.
-
File exists.
-
Bad address.
-
File too large.
-
Host is unreachable.
-
Identifier removed.
-
Illegal byte sequence.
-
Operation in progress.
-
Interrupted function.
-
Invalid argument.
-
I/O error.
-
Socket is connected.
-
Is a directory.
-
Too many levels of symbolic links.
-
File descriptor value too large.
-
Too many links.
-
Message too large.
-
Reserved.
-
Filename too long.
-
Network is down.
-
Connection aborted by network.
-
Network unreachable.
-
Too many files open in system.
-
No buffer space available.
-
No such device.
-
No such file or directory.
-
Executable file format error.
-
No locks available.
-
Reserved.
-
Not enough space.
-
No message of the desired type.
-
Protocol not available.
-
No space left on device.
-
Function not supported.
-
The socket is not connected.
-
Not a directory or a symbolic link to a directory.
-
Directory not empty.
-
State not recoverable.
-
Not a socket.
-
Not supported, or operation not supported on socket.
-
Inappropriate I/O control operation.
-
No such device or address.
-
Value too large to be stored in data type.
-
Previous owner died.
-
Operation not permitted.
-
Broken pipe.
-
Protocol error.
-
Protocol not supported.
-
Protocol wrong type for socket.
-
Result too large.
-
Read-only file system.
-
Invalid seek.
-
No such process.
-
Reserved.
-
Connection timed out.
-
Text file busy.
-
Cross-device link.
-
Extension: Capabilities insufficient.
An event that occurred.
Used by uvwasi_poll_oneoff()
.
Members:
-
__wasi_userdata_t userdata
User-provided value that got attached to
uvwasi_subscription_t::userdata
. -
__wasi_errno_t error
If non-zero, an error that occurred while processing the subscription request.
-
__wasi_eventtype_t type
The type of the event that occurred.
-
When
type
isUVWASI_EVENTTYPE_FD_READ
orUVWASI_EVENTTYPE_FD_WRITE
:-
-
__wasi_filesize_t nbytes
The number of bytes available for reading or writing.
-
__wasi_eventrwflags_t flags
The state of the file descriptor.
-
-
The state of the file descriptor subscribed to with
UVWASI_EVENTTYPE_FD_READ
or UVWASI_EVENTTYPE_FD_WRITE
.
Used by uvwasi_event_t
.
Possible values:
Type of a subscription to an event or its occurrence.
Used by uvwasi_event_t
and uvwasi_subscription_t
.
Possible values:
-
The time value of clock
uvwasi_subscription_t::u.clock.clock_id
has reached timestampuvwasi_subscription_t::u.clock.timeout
. -
File descriptor
uvwasi_subscription_t::u.fd_readwrite.fd
has data available for reading. This event always triggers for regular files. -
File descriptor
uvwasi_subscription_t::u.fd_readwrite.fd
has capacity available for writing. This event always triggers for regular files.
Exit code generated by a process when exiting.
Used by uvwasi_proc_exit()
.
A file descriptor number.
Used by many functions in this API.
As in POSIX, three file descriptor numbers are provided to instances
on startup -- 0, 1, and 2, (a.k.a. STDIN_FILENO
, STDOUT_FILENO
,
and STDERR_FILENO
).
Other than these, WASI implementations are not required to allocate new file descriptors in ascending order.
File descriptor flags.
Used by uvwasi_fdstat_t
, uvwasi_fd_fdstat_set_flags()
, and uvwasi_path_open()
.
Possible values:
-
Append mode: Data written to the file is always appended to the file's end.
-
Write according to synchronized I/O data integrity completion. Only the data stored in the file is synchronized.
-
Non-blocking mode.
-
Synchronized read I/O operations.
-
Write according to synchronized I/O file integrity completion. In addition to synchronizing the data stored in the file, the implementation may also synchronously update the file's metadata.
File descriptor attributes.
Used by uvwasi_fd_fdstat_get()
.
Members:
-
__wasi_filetype_t fs_filetype
File type.
-
__wasi_fdflags_t fs_flags
File descriptor flags.
-
__wasi_rights_t fs_rights_base
Rights that apply to this file descriptor.
-
__wasi_rights_t fs_rights_inheriting
Maximum set of rights that may be installed on new file descriptors that are created through this file descriptor, e.g., through
uvwasi_path_open()
.
Relative offset within a file.
Used by uvwasi_fd_seek()
.
Non-negative file size or length of a region within a file.
Used by uvwasi_event_t
, uvwasi_filestat_t
, uvwasi_fd_pread()
, uvwasi_fd_pwrite()
, uvwasi_fd_seek()
, uvwasi_path_tell()
, uvwasi_fd_advise()
, uvwasi_fd_allocate()
, and uvwasi_fd_filestat_set_size()
.
File attributes.
Used by uvwasi_fd_filestat_get()
and uvwasi_path_filestat_get()
.
Members:
-
__wasi_device_t st_dev
Device ID of device containing the file.
-
__wasi_inode_t st_ino
File serial number.
-
__wasi_filetype_t st_filetype
File type.
-
__wasi_linkcount_t st_nlink
Number of hard links to the file.
-
__wasi_filesize_t st_size
For regular files, the file size in bytes. For symbolic links, the length in bytes of the pathname contained in the symbolic link.
-
__wasi_timestamp_t st_atim
Last data access timestamp.
-
__wasi_timestamp_t st_mtim
Last data modification timestamp.
-
__wasi_timestamp_t st_ctim
Last file status change timestamp.
The type of a file descriptor or file.
Used by uvwasi_dirent_t
, uvwasi_fdstat_t
, and uvwasi_filestat_t
.
Possible values:
-
The type of the file descriptor or file is unknown or is different from any of the other types specified.
-
The file descriptor or file refers to a block device inode.
-
UVWASI_FILETYPE_CHARACTER_DEVICE
The file descriptor or file refers to a character device inode.
-
The file descriptor or file refers to a directory inode.
-
The file descriptor or file refers to a regular file inode.
-
The file descriptor or file refers to a datagram socket.
-
The file descriptor or file refers to a byte-stream socket.
-
The file refers to a symbolic link inode.
Which file time attributes to adjust.
Used by uvwasi_fd_filestat_set_times()
and uvwasi_path_filestat_set_times()
.
Possible values:
-
Adjust the last data access timestamp to the value stored in
uvwasi_filestat_t::st_atim
. -
Adjust the last data access timestamp to the time of clock
UVWASI_CLOCK_REALTIME
. -
Adjust the last data modification timestamp to the value stored in
uvwasi_filestat_t::st_mtim
. -
Adjust the last data modification timestamp to the time of clock
UVWASI_CLOCK_REALTIME
.
File serial number that is unique within its file system.
Used by uvwasi_dirent_t
and uvwasi_filestat_t
.
A region of memory for scatter/gather reads.
Used by uvwasi_fd_pread()
, uvwasi_fd_read()
, and uvwasi_sock_recv()
.
Members:
Number of hard links to an inode.
Used by uvwasi_filestat_t
.
Flags determining the method of how paths are resolved.
Used by uvwasi_path_filestat_get()
, uvwasi_path_filestat_set_times()
, uvwasi_path_link()
, and uvwasi_path_open()
.
Possible values:
-
As long as the resolved path corresponds to a symbolic link, it is expanded.
Open flags used by uvwasi_path_open()
.
Used by uvwasi_path_open()
.
Possible values:
-
Create file if it does not exist.
-
Fail if not a directory.
-
Fail if file already exists.
-
Truncate file to size 0.
Flags provided to uvwasi_sock_recv()
.
Used by uvwasi_sock_recv()
.
Possible values:
-
Returns the message without removing it from the socket's receive queue.
-
On byte-stream sockets, block until the full amount of data can be returned.
File descriptor rights, determining which actions may be performed.
Used by uvwasi_fdstat_t
, uvwasi_fd_fdstat_set_rights()
, and uvwasi_path_open()
.
Possible values:
-
The right to invoke
uvwasi_fd_datasync()
.If
UVWASI_RIGHT_PATH_OPEN
is set, includes the right to invokeuvwasi_path_open()
withUVWASI_FDFLAG_DSYNC
. -
The right to invoke
uvwasi_fd_read()
anduvwasi_sock_recv()
.If
UVWASI_RIGHT_FD_SEEK
is set, includes the right to invokeuvwasi_fd_pread()
. -
The right to invoke
uvwasi_fd_seek()
. This flag impliesUVWASI_RIGHT_FD_TELL
. -
UVWASI_RIGHT_FD_FDSTAT_SET_FLAGS
The right to invoke
uvwasi_fd_fdstat_set_flags()
. -
The right to invoke
uvwasi_fd_sync()
.If
UVWASI_RIGHT_PATH_OPEN
is set, includes the right to invokeuvwasi_path_open()
withUVWASI_FDFLAG_RSYNC
andUVWASI_FDFLAG_DSYNC
. -
The right to invoke
uvwasi_fd_seek()
in such a way that the file offset remains unaltered (i.e.,UVWASI_WHENCE_CUR
with offset zero), or to invokeuvwasi_fd_tell()
. -
The right to invoke
uvwasi_fd_write()
anduvwasi_sock_send()
.If
UVWASI_RIGHT_FD_SEEK
is set, includes the right to invokeuvwasi_fd_pwrite()
. -
The right to invoke
uvwasi_fd_advise()
. -
The right to invoke
uvwasi_fd_allocate()
. -
UVWASI_RIGHT_PATH_CREATE_DIRECTORY
The right to invoke
uvwasi_path_create_directory()
. -
If
UVWASI_RIGHT_PATH_OPEN
is set, the right to invokeuvwasi_path_open()
withUVWASI_O_CREAT
. -
The right to invoke
uvwasi_path_link()
with the file descriptor as the source directory. -
The right to invoke
uvwasi_path_link()
with the file descriptor as the target directory. -
The right to invoke
uvwasi_path_open()
. -
The right to invoke
uvwasi_fd_readdir()
. -
The right to invoke
uvwasi_path_readlink()
. -
UVWASI_RIGHT_PATH_RENAME_SOURCE
The right to invoke
uvwasi_path_rename()
with the file descriptor as the source directory. -
UVWASI_RIGHT_PATH_RENAME_TARGET
The right to invoke
uvwasi_path_rename()
with the file descriptor as the target directory. -
UVWASI_RIGHT_PATH_FILESTAT_GET
The right to invoke
uvwasi_path_filestat_get()
. -
UVWASI_RIGHT_PATH_FILESTAT_SET_SIZE
The right to change a file's size (there is no
uvwasi_path_filestat_set_size()
).If
UVWASI_RIGHT_PATH_OPEN
is set, includes the right to invokeuvwasi_path_open()
withUVWASI_O_TRUNC
. -
UVWASI_RIGHT_PATH_FILESTAT_SET_TIMES
The right to invoke
uvwasi_path_filestat_set_times()
. -
The right to invoke
uvwasi_fd_filestat_get()
. -
UVWASI_RIGHT_FD_FILESTAT_SET_SIZE
The right to invoke
uvwasi_fd_filestat_set_size()
. -
UVWASI_RIGHT_FD_FILESTAT_SET_TIMES
The right to invoke
uvwasi_fd_filestat_set_times()
. -
The right to invoke
uvwasi_path_symlink()
. -
The right to invoke
uvwasi_path_unlink_file()
. -
UVWASI_RIGHT_PATH_REMOVE_DIRECTORY
The right to invoke
uvwasi_path_remove_directory()
. -
UVWASI_RIGHT_POLL_FD_READWRITE
If
UVWASI_RIGHT_FD_READ
is set, includes the right to invokeuvwasi_poll_oneoff()
to subscribe toUVWASI_EVENTTYPE_FD_READ
.If
UVWASI_RIGHT_FD_WRITE
is set, includes the right to invokeuvwasi_poll_oneoff()
to subscribe toUVWASI_EVENTTYPE_FD_WRITE
. -
The right to invoke
uvwasi_sock_shutdown()
.
Flags returned by uvwasi_sock_recv()
.
Used by uvwasi_sock_recv()
.
Possible values:
-
UVWASI_SOCK_RECV_DATA_TRUNCATED
Returned by
uvwasi_sock_recv()
: Message data has been truncated.
Which channels on a socket to shut down.
Used by uvwasi_sock_shutdown()
.
Possible values:
-
Disables further receive operations.
-
Disables further send operations.
Flags provided to uvwasi_sock_send()
. As there are currently no flags
defined, it must be set to zero.
Used by uvwasi_sock_send()
.
Signal condition.
Used by uvwasi_proc_raise()
.
Possible values:
-
Process abort signal.
Action: Terminates the process.
-
Alarm clock.
Action: Terminates the process.
-
Access to an undefined portion of a memory object.
Action: Terminates the process.
-
Child process terminated, stopped, or continued.
Action: Ignored.
-
Continue executing, if stopped.
Action: Continues executing, if stopped.
-
Erroneous arithmetic operation.
Action: Terminates the process.
-
Hangup.
Action: Terminates the process.
-
Illegal instruction.
Action: Terminates the process.
-
Terminate interrupt signal.
Action: Terminates the process.
-
Kill.
Action: Terminates the process.
-
Write on a pipe with no one to read it.
Action: Ignored.
-
Terminal quit signal.
Action: Terminates the process.
-
Invalid memory reference.
Action: Terminates the process.
-
Stop executing.
Action: Stops executing.
-
Bad system call.
Action: Terminates the process.
-
Termination signal.
Action: Terminates the process.
-
Trace/breakpoint trap.
Action: Terminates the process.
-
Terminal stop signal.
Action: Stops executing.
-
Background process attempting read.
Action: Stops executing.
-
Background process attempting write.
Action: Stops executing.
-
High bandwidth data is available at a socket.
Action: Ignored.
-
User-defined signal 1.
Action: Terminates the process.
-
User-defined signal 2.
Action: Terminates the process.
-
Virtual timer expired.
Action: Terminates the process.
-
CPU time limit exceeded.
Action: Terminates the process.
-
File size limit exceeded.
Action: Terminates the process.
Flags determining how to interpret the timestamp provided in
uvwasi_subscription_t::u.clock.timeout
.
Used by uvwasi_subscription_t
.
Possible values:
-
UVWASI_SUBSCRIPTION_CLOCK_ABSTIME
If set, treat the timestamp provided in
uvwasi_subscription_t::u.clock.timeout
as an absolute timestamp of clockuvwasi_subscription_t::u.clock.clock_id
.If clear, treat the timestamp provided in
uvwasi_subscription_t::u.clock.timeout
relative to the current time value of clockuvwasi_subscription_t::u.clock.clock_id
.
Subscription to an event.
Used by uvwasi_poll_oneoff()
.
Members:
-
__wasi_userdata_t userdata
User-provided value that is attached to the subscription in the implementation and returned through
uvwasi_event_t::userdata
. -
__wasi_eventtype_t type
The type of the event to which to subscribe.
-
When
type
isUVWASI_EVENTTYPE_CLOCK
:-
-
__wasi_clockid_t clock_id
The clock against which to compare the timestamp.
-
__wasi_timestamp_t timeout
The absolute or relative timestamp.
-
__wasi_timestamp_t precision
The amount of time that the implementation may wait additionally to coalesce with other events.
-
__wasi_subclockflags_t flags
Flags specifying whether the timeout is absolute or relative.
-
-
-
When
type
isUVWASI_EVENTTYPE_FD_READ
orUVWASI_EVENTTYPE_FD_WRITE
:-
-
__wasi_fd_t fd
The file descriptor on which to wait for it to become ready for reading or writing.
-
-
Timestamp in nanoseconds.
Used by uvwasi_filestat_t
, uvwasi_subscription_t
, uvwasi_clock_res_get()
, uvwasi_clock_time_get()
, uvwasi_fd_filestat_set_times()
, and uvwasi_path_filestat_set_times()
.
User-provided value that may be attached to objects that is retained when extracted from the implementation.
Used by uvwasi_event_t
and uvwasi_subscription_t
.
The position relative to which to set the offset of the file descriptor.
Used by uvwasi_fd_seek()
.
Possible values: