wasi-common: deprecate fd_allocate (#6217)

* wasi-common: remove allocate from WasiFile trait, always fail with NOTSUP

This operation from cloudabi is linux-specific, isn't even
supported across all linux filesystems, and has no support on macos
or windows. Rather than ship spotty support, it has been removed
from preview 2, and we are no longer supporting it in preview 1 as
well.

The preview 1 implementation will still check if fd is a file, and has
rights, just to reject those cases with the errors expected.

* wasi-tests: expect fd_allocate to always fail now.

rewrite the file_allocate test to just check for failure.

remove use of fd_allocate from fd_advise test, and remove test
configuration setting used for excluding use of fd_allocate on macos and
windows.

crates/test-programs/tests/wasm_tests/runtime/mod.rs

@@ -12,8 +12,6 @@ pub fn test_suite_environment() -> &'static [(&'static str, &'static str)] {
             ("ERRNO_MODE_WINDOWS", "1"),
             // Windows does not support dangling links or symlinks in the filesystem.
             ("NO_DANGLING_FILESYSTEM", "1"),
-            // Windows does not support fd_allocate.
-            ("NO_FD_ALLOCATE", "1"),
             // Windows does not support renaming a directory to an empty directory -
             // empty directory must be deleted.
             ("NO_RENAME_DIR_TO_EMPTY_DIR", "1"),
@@ -25,10 +23,6 @@ pub fn test_suite_environment() -> &'static [(&'static str, &'static str)] {
     }
     #[cfg(target_os = "macos")]
     {
-        &[
+        &[("ERRNO_MODE_MACOS", "1")]
-            ("ERRNO_MODE_MACOS", "1"),
-            // MacOS does not support fd_allocate
-            ("NO_FD_ALLOCATE", "1"),
-        ]
     }
 }

crates/test-programs/wasi-tests/src/bin/fd_advise.rs

@@ -1,5 +1,5 @@
 use std::{env, process};
-use wasi_tests::{open_scratch_directory, TESTCONFIG};
+use wasi_tests::open_scratch_directory;
 
 unsafe fn test_fd_advise(dir_fd: wasi::Fd) {
     // Create a file in the scratch directory.
@@ -40,14 +40,6 @@ unsafe fn test_fd_advise(dir_fd: wasi::Fd) {
     let stat = wasi::fd_filestat_get(file_fd).expect("failed to fdstat 3");
     assert_eq!(stat.size, 100, "file size should be 100");
 
-    if TESTCONFIG.support_fd_allocate() {
-        // Use fd_allocate to expand size to 200:
-        wasi::fd_allocate(file_fd, 100, 100).expect("allocating size");
-
-        let stat = wasi::fd_filestat_get(file_fd).expect("failed to fdstat 3");
-        assert_eq!(stat.size, 200, "file size should be 200");
-    }
-
     wasi::fd_close(file_fd).expect("failed to close");
     wasi::path_unlink_file(dir_fd, "file").expect("failed to unlink");
 }

crates/test-programs/wasi-tests/src/bin/file_allocate.rs

@@ -1,5 +1,5 @@
 use std::{env, process};
-use wasi_tests::{open_scratch_directory, TESTCONFIG};
+use wasi_tests::open_scratch_directory;
 
 unsafe fn test_file_allocate(dir_fd: wasi::Fd) {
     // Create a file in the scratch directory.
@@ -25,22 +25,18 @@ unsafe fn test_file_allocate(dir_fd: wasi::Fd) {
     let mut stat = wasi::fd_filestat_get(file_fd).expect("reading file stats");
     assert_eq!(stat.size, 0, "file size should be 0");
 
-    if TESTCONFIG.support_fd_allocate() {
+    let err = wasi::fd_allocate(file_fd, 0, 100)
-        // Allocate some size
+        .err()
-        wasi::fd_allocate(file_fd, 0, 100).expect("allocating size");
+        .expect("fd_allocate must fail");
-        stat = wasi::fd_filestat_get(file_fd).expect("reading file stats");
+    assert_eq!(
-        assert_eq!(stat.size, 100, "file size should be 100");
+        err,
+        wasi::ERRNO_NOTSUP,
+        "fd_allocate should fail with NOTSUP"
+    );
 
-        // Allocate should not modify if less than current size
-        wasi::fd_allocate(file_fd, 10, 10).expect("allocating size less than current size");
     stat = wasi::fd_filestat_get(file_fd).expect("reading file stats");
-        assert_eq!(stat.size, 100, "file size should remain unchanged at 100");
+    assert_eq!(stat.size, 0, "file size should still be 0");
 
-        // Allocate should modify if offset+len > current_len
-        wasi::fd_allocate(file_fd, 90, 20).expect("allocating size larger than current size");
-        stat = wasi::fd_filestat_get(file_fd).expect("reading file stats");
-        assert_eq!(stat.size, 110, "file size should increase from 100 to 110");
-    }
     wasi::fd_close(file_fd).expect("closing a file");
     wasi::path_unlink_file(dir_fd, "file").expect("removing a file");
 }

crates/test-programs/wasi-tests/src/config.rs

@@ -1,7 +1,6 @@
 pub struct TestConfig {
     errno_mode: ErrnoMode,
     no_dangling_filesystem: bool,
-    no_fd_allocate: bool,
     no_rename_dir_to_empty_dir: bool,
     no_fdflags_sync_support: bool,
 }
@@ -25,13 +24,11 @@ impl TestConfig {
             ErrnoMode::Permissive
         };
         let no_dangling_filesystem = std::env::var("NO_DANGLING_FILESYSTEM").is_ok();
-        let no_fd_allocate = std::env::var("NO_FD_ALLOCATE").is_ok();
         let no_rename_dir_to_empty_dir = std::env::var("NO_RENAME_DIR_TO_EMPTY_DIR").is_ok();
         let no_fdflags_sync_support = std::env::var("NO_FDFLAGS_SYNC_SUPPORT").is_ok();
         TestConfig {
             errno_mode,
             no_dangling_filesystem,
-            no_fd_allocate,
             no_rename_dir_to_empty_dir,
             no_fdflags_sync_support,
         }
@@ -57,9 +54,6 @@ impl TestConfig {
     pub fn support_dangling_filesystem(&self) -> bool {
         !self.no_dangling_filesystem
     }
-    pub fn support_fd_allocate(&self) -> bool {
-        !self.no_fd_allocate
-    }
     pub fn support_rename_dir_to_empty_dir(&self) -> bool {
         !self.no_rename_dir_to_empty_dir
     }

crates/wasi-common/cap-std-sync/src/file.rs

@@ -84,10 +84,6 @@ impl WasiFile for File {
         self.0.advise(offset, len, convert_advice(advice))?;
         Ok(())
     }
-    async fn allocate(&self, offset: u64, len: u64) -> Result<(), Error> {
-        self.0.allocate(offset, len)?;
-        Ok(())
-    }
     async fn set_times(
         &self,
         atime: Option<wasi_common::SystemTimeSpec>,

crates/wasi-common/src/file.rs

@@ -83,10 +83,6 @@ pub trait WasiFile: Send + Sync {
         Err(Error::badf())
     }
 
-    async fn allocate(&self, _offset: u64, _len: u64) -> Result<(), Error> {
-        Err(Error::badf())
-    }
-
     async fn set_times(
         &self,
         _atime: Option<SystemTimeSpec>,

crates/wasi-common/src/snapshots/preview_1.rs

@@ -123,15 +123,21 @@ impl wasi_snapshot_preview1::WasiSnapshotPreview1 for WasiCtx {
     async fn fd_allocate(
         &mut self,
         fd: types::Fd,
-        offset: types::Filesize,
+        _offset: types::Filesize,
-        len: types::Filesize,
+        _len: types::Filesize,
     ) -> Result<(), Error> {
-        self.table()
+        // Check if fd is a file, and has rights, just to reject those cases
+        // with the errors expected:
+        let _ = self
+            .table()
             .get_file(u32::from(fd))?
-            .get_cap(FileCaps::ALLOCATE)?
+            .get_cap(FileCaps::ALLOCATE)?;
-            .allocate(offset, len)
+        // This operation from cloudabi is linux-specific, isn't even
-            .await?;
+        // supported across all linux filesystems, and has no support on macos
-        Ok(())
+        // or windows. Rather than ship spotty support, it has been removed
+        // from preview 2, and we are no longer supporting it in preview 1 as
+        // well.
+        Err(Error::not_supported())
     }
 
     async fn fd_close(&mut self, fd: types::Fd) -> Result<(), Error> {

crates/wasi-common/tokio/src/file.rs

@@ -127,9 +127,6 @@ macro_rules! wasi_file_impl {
             async fn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error> {
                 block_on_dummy_executor(move || self.0.advise(offset, len, advice))
             }
-            async fn allocate(&self, offset: u64, len: u64) -> Result<(), Error> {
-                block_on_dummy_executor(move || self.0.allocate(offset, len))
-            }
             async fn read_vectored<'a>(
                 &self,
                 bufs: &mut [io::IoSliceMut<'a>],