Very rough very experimental very preliminary NuttX proof-of-concept …

…port.

Cargo.toml

@@ -18,7 +18,7 @@ include = ["src", "build.rs", "Cargo.toml", "COPYRIGHT", "LICENSE*", "/*.md"]
 cc = { version = "1.0.68", optional = true }
 
 [dependencies]
-bitflags = "1.2.1"
+bitflags = { version = "1.2.1", default-features = false }
 itoa = { version = "1.0.1", default-features = false, optional = true }
 io-lifetimes = { version = "0.7.0", default-features = false, optional = true }
 
@@ -27,6 +27,9 @@ core = { version = "1.0.0", optional = true, package = "rustc-std-workspace-core
 alloc = { version = "1.0.0", optional = true, package = "rustc-std-workspace-alloc" }
 compiler_builtins = { version = '0.1.49', optional = true }
 
+# The NuttX API.
+nuttx-sys = { git = "https://github.com/sunfishcode/nuttx-sys", features = ["build_flat", "pipes", "dev_pipe", "sched_user_identity", "sched_have_parent"] }
+
 # The procfs feature needs once_cell.
 [target.'cfg(any(target_os = "android", target_os = "linux"))'.dependencies]
 once_cell = { version = "1.5.2", optional = true }
@@ -39,16 +42,16 @@ once_cell = { version = "1.5.2", optional = true }
 # `RUSTFLAGS` or enabling the `use-libc` cargo feature.
 [target.'cfg(all(not(rustix_use_libc), not(miri), target_os = "linux", any(target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64"), all(target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "powerpc64", target_arch = "riscv64", target_arch = "mips", target_arch = "mips64")))))'.dependencies]
 linux-raw-sys = { version = "0.0.46", default-features = false, features = ["general", "errno", "ioctl", "no_std"] }
-libc_errno = { package = "errno", version = "0.2.8", default-features = false, optional = true }
-libc = { version = "0.2.126", features = ["extra_traits"], optional = true }
+#libc_errno = { package = "errno", version = "0.2.8", default-features = false, optional = true }
+#libc = { version = "0.2.126", features = ["extra_traits"], optional = true }
 
 # Dependencies for platforms where only libc is supported:
 #
 # On all other Unix-family platforms, and under Miri, we always use the libc
 # backend, so enable its dependencies unconditionally.
 [target.'cfg(any(rustix_use_libc, miri, not(all(target_os = "linux", any(target_arch = "x86", all(target_arch = "x86_64", target_pointer_width = "64"), all(target_endian = "little", any(target_arch = "arm", all(target_arch = "aarch64", target_pointer_width = "64"), target_arch = "powerpc64", target_arch = "riscv64", target_arch = "mips", target_arch = "mips64")))))))'.dependencies]
-libc_errno = { package = "errno", version = "0.2.8", default-features = false }
-libc = { version = "0.2.126", features = ["extra_traits"] }
+#libc_errno = { package = "errno", version = "0.2.8", default-features = false }
+#libc = { version = "0.2.126", features = ["extra_traits"] }
 
 # Additional dependencies for Linux with the libc backend:
 #
@@ -122,7 +125,7 @@ rustc-dep-of-std = [
 ]
 
 # Enable this to request the libc backend.
-use-libc = ["libc_errno", "libc"]
+use-libc = []
 
 # Enable `rustix::fs::*`.
 fs = []
@@ -179,7 +182,7 @@ all-apis = [
 # When using the linux_raw backend, and not using Mustang, should we use libc
 # for reading the aux vectors, instead of reading them ourselves from
 # /proc/self/auxv?
-use-libc-auxv = ["libc"]
+use-libc-auxv = []
 
 # Expose io-lifetimes' features for third-party crate impls.
 async-std = ["io-lifetimes/async-std"]

build.rs

@@ -40,7 +40,7 @@ fn main() {
 
     // Check for `--features=use-libc`. This allows crate users to enable the
     // libc backend.
-    let feature_use_libc = var("CARGO_FEATURE_USE_LIBC").is_ok();
+    let feature_use_libc = true; // For now, always enable this on the NuttX branch.
 
     // Check for `--features=rustc-dep-of-std`. This is used when rustix is
     // being used to build std, in which case `can_compile` doesn't work

src/backend/libc/fs/mod.rs

@@ -1,3 +1,4 @@
+/*
 #[cfg(not(target_os = "redox"))]
 #[cfg(any(feature = "fs", feature = "procfs"))]
 pub(crate) mod dir;
@@ -13,6 +14,7 @@ pub(crate) mod dir;
     target_os = "wasi",
 )))]
 pub(crate) mod makedev;
+*/
 #[cfg(not(windows))]
 pub(crate) mod syscalls;
 pub(crate) mod types;

src/backend/libc/fs/syscalls.rs

@@ -6,6 +6,7 @@ use super::super::conv::{
 };
 #[cfg(any(target_os = "android", target_os = "linux"))]
 use super::super::conv::{syscall_ret, syscall_ret_owned_fd, syscall_ret_ssize_t};
+/*
 #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
 use super::super::offset::libc_fallocate;
 #[cfg(not(any(
@@ -31,16 +32,19 @@ use super::super::offset::libc_posix_fadvise;
     target_os = "redox",
 )))]
 use super::super::offset::libc_posix_fallocate;
-use super::super::offset::{libc_fstat, libc_fstatat, libc_ftruncate, libc_lseek, libc_off_t};
+*/
+use super::super::offset::{libc_fstat, /*libc_fstatat,*/ libc_ftruncate, libc_lseek, libc_off_t};
 #[cfg(not(any(
     target_os = "illumos",
     target_os = "netbsd",
     target_os = "redox",
     target_os = "wasi",
 )))]
 use super::super::offset::{libc_fstatfs, libc_statfs};
+/*
 #[cfg(not(any(target_os = "illumos", target_os = "redox", target_os = "wasi")))]
 use super::super::offset::{libc_fstatvfs, libc_statvfs};
+*/
 #[cfg(all(
     any(target_arch = "arm", target_arch = "mips", target_arch = "x86"),
     target_env = "gnu",
@@ -54,6 +58,7 @@ use crate::ffi::CStr;
 use crate::ffi::CString;
 #[cfg(not(target_os = "illumos"))]
 use crate::fs::Access;
+/*
 #[cfg(not(any(
     target_os = "dragonfly",
     target_os = "illumos",
@@ -74,6 +79,7 @@ use crate::fs::Advice;
 use crate::fs::FallocateFlags;
 #[cfg(not(target_os = "wasi"))]
 use crate::fs::FlockOperation;
+*/
 #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
 use crate::fs::MemfdFlags;
 #[cfg(any(
@@ -100,8 +106,10 @@ use crate::fs::{cwd, RenameFlags, ResolveFlags, Statx, StatxFlags};
 )))]
 use crate::fs::{Dev, FileType};
 use crate::fs::{FdFlags, Mode, OFlags, Stat, Timestamps};
+/*
 #[cfg(not(any(target_os = "illumos", target_os = "redox", target_os = "wasi")))]
 use crate::fs::{StatVfs, StatVfsMountFlags};
+*/
 use crate::io::{self, OwnedFd, SeekFrom};
 #[cfg(not(target_os = "wasi"))]
 use crate::process::{Gid, Uid};
@@ -133,6 +141,7 @@ use {
     super::super::conv::nonnegative_ret,
     crate::fs::{copyfile_state_t, CloneFlags, CopyfileFlags},
 };
+/*
 #[cfg(not(target_os = "redox"))]
 use {super::super::offset::libc_openat, crate::fs::AtFlags};
 
@@ -197,6 +206,7 @@ pub(crate) fn openat(
         ))
     }
 }
+*/
 
 #[cfg(not(any(
     target_os = "illumos",
@@ -213,6 +223,7 @@ pub(crate) fn statfs(filename: &CStr) -> io::Result<StatFs> {
     }
 }
 
+/*
 #[cfg(not(any(target_os = "illumos", target_os = "redox", target_os = "wasi")))]
 #[inline]
 pub(crate) fn statvfs(filename: &CStr) -> io::Result<StatVfs> {
@@ -806,6 +817,7 @@ pub(crate) fn fadvise(fd: BorrowedFd<'_>, offset: u64, len: u64, advice: Advice)
         Err(io::Errno(err))
     }
 }
+*/
 
 pub(crate) fn fcntl_getfd(fd: BorrowedFd<'_>) -> io::Result<FdFlags> {
     unsafe { ret_c_int(c::fcntl(borrowed_fd(fd), c::F_GETFD)).map(FdFlags::from_bits_truncate) }
@@ -846,6 +858,7 @@ pub(crate) fn fcntl_add_seals(fd: BorrowedFd<'_>, seals: SealFlags) -> io::Resul
     unsafe { ret(c::fcntl(borrowed_fd(fd), c::F_ADD_SEALS, seals.bits())) }
 }
 
+/*
 #[cfg(not(target_os = "wasi"))]
 pub(crate) fn fcntl_dupfd_cloexec(fd: BorrowedFd<'_>, min: RawFd) -> io::Result<OwnedFd> {
     unsafe { ret_owned_fd(c::fcntl(borrowed_fd(fd), c::F_DUPFD_CLOEXEC, min)) }
@@ -864,6 +877,7 @@ pub(crate) fn seek(fd: BorrowedFd<'_>, pos: SeekFrom) -> io::Result<u64> {
     let offset = unsafe { ret_off_t(libc_lseek(borrowed_fd(fd), offset, whence))? };
     Ok(offset as u64)
 }
+*/
 
 pub(crate) fn tell(fd: BorrowedFd<'_>) -> io::Result<u64> {
     let offset = unsafe { ret_off_t(libc_lseek(borrowed_fd(fd), 0, c::SEEK_CUR))? };
@@ -910,10 +924,12 @@ pub(crate) fn fchown(fd: BorrowedFd<'_>, owner: Option<Uid>, group: Option<Gid>)
     }
 }
 
+/*
 #[cfg(not(target_os = "wasi"))]
 pub(crate) fn flock(fd: BorrowedFd<'_>, operation: FlockOperation) -> io::Result<()> {
     unsafe { ret(c::flock(borrowed_fd(fd), operation as c::c_int)) }
 }
+*/
 
 pub(crate) fn fstat(fd: BorrowedFd<'_>) -> io::Result<Stat> {
     // 32-bit and mips64 Linux: `struct stat64` is not y2038 compatible; use
@@ -969,6 +985,7 @@ pub(crate) fn fstatfs(fd: BorrowedFd<'_>) -> io::Result<StatFs> {
     }
 }
 
+/*
 #[cfg(not(any(target_os = "illumos", target_os = "redox", target_os = "wasi")))]
 pub(crate) fn fstatvfs(fd: BorrowedFd<'_>) -> io::Result<StatVfs> {
     let mut statvfs = MaybeUninit::<libc_statvfs>::uninit();
@@ -994,6 +1011,7 @@ fn libc_statvfs_to_statvfs(from: libc_statvfs) -> StatVfs {
         f_namemax: from.f_namemax as u64,
     }
 }
+*/
 
 pub(crate) fn futimens(fd: BorrowedFd<'_>, times: &Timestamps) -> io::Result<()> {
     // 32-bit gnu version: libc has `futimens` but it is not y2038 safe by default.
@@ -1096,6 +1114,7 @@ unsafe fn futimens_old(fd: BorrowedFd<'_>, times: &Timestamps) -> io::Result<()>
     ret(c::futimens(borrowed_fd(fd), old_times.as_ptr()))
 }
 
+/*
 #[cfg(not(any(
     target_os = "dragonfly",
     target_os = "illumos",
@@ -1133,6 +1152,7 @@ pub(crate) fn fallocate(
         }
     }
 }
+*/
 
 #[cfg(any(target_os = "ios", target_os = "macos"))]
 pub(crate) fn fallocate(
@@ -1174,7 +1194,7 @@ pub(crate) fn fsync(fd: BorrowedFd<'_>) -> io::Result<()> {
     target_os = "redox",
 )))]
 pub(crate) fn fdatasync(fd: BorrowedFd<'_>) -> io::Result<()> {
-    unsafe { ret(c::fdatasync(borrowed_fd(fd))) }
+    unsafe { ret(c::fsync(borrowed_fd(fd))) }
 }
 
 pub(crate) fn ftruncate(fd: BorrowedFd<'_>, length: u64) -> io::Result<()> {

src/backend/libc/fs/types.rs

@@ -31,6 +31,7 @@ bitflags! {
     }
 }
 
+/*
 #[cfg(not(target_os = "redox"))]
 bitflags! {
     /// `AT_*` constants for use with [`openat`], [`statat`], and other `*at`
@@ -73,6 +74,7 @@ bitflags! {
         const STATX_DONT_SYNC = c::AT_STATX_DONT_SYNC;
     }
 }
+*/
 
 bitflags! {
     /// `S_I*` constants for use with [`openat`], [`chmodat`], and [`fchmod`].
@@ -204,8 +206,10 @@ bitflags! {
         ))]
         const FSYNC = c::O_FSYNC;
 
+        /*
         /// `O_NOFOLLOW`
         const NOFOLLOW = c::O_NOFOLLOW;
+        */
 
         /// `O_NONBLOCK`
         const NONBLOCK = c::O_NONBLOCK;
@@ -456,6 +460,7 @@ impl FileType {
     }
 }
 
+/*
 /// `POSIX_FADV_*` constants for use with [`fadvise`].
 ///
 /// [`fadvise`]: crate::fs::fadvise
@@ -489,6 +494,7 @@ pub enum Advice {
     /// `POSIX_FADV_DONTNEED`
     DontNeed = c::POSIX_FADV_DONTNEED as c::c_uint,
 }
+*/
 
 #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
 bitflags! {
@@ -680,6 +686,7 @@ bitflags! {
     }
 }
 
+/*
 #[cfg(not(any(
     target_os = "illumos",
     target_os = "netbsd",
@@ -777,7 +784,9 @@ bitflags! {
         const UNSHARE_RANGE = c::FALLOC_FL_UNSHARE_RANGE;
     }
 }
+*/
 
+/*
 #[cfg(not(any(target_os = "illumos", target_os = "redox", target_os = "wasi",)))]
 bitflags! {
     /// `ST_*` constants for use with [`StatVfs`].
@@ -838,6 +847,7 @@ pub enum FlockOperation {
     /// `LOCK_UN | LOCK_NB`
     NonBlockingUnlock = c::LOCK_UN | c::LOCK_NB,
 }
+*/
 
 /// `struct stat` for use with [`statat`] and [`fstat`].
 ///
@@ -943,7 +953,7 @@ pub struct StatVfs {
     pub f_ffree: u64,
     pub f_favail: u64,
     pub f_fsid: u64,
-    pub f_flag: StatVfsMountFlags,
+    /*pub f_flag: StatVfsMountFlags, */
     pub f_namemax: u64,
 }
 
@@ -1055,8 +1065,10 @@ pub type FsWord = u64;
 #[cfg(all(target_os = "linux", target_arch = "s390x"))]
 pub type FsWord = u32;
 
+/*
 #[cfg(not(target_os = "redox"))]
 pub use c::{UTIME_NOW, UTIME_OMIT};
+*/
 
 /// `PROC_SUPER_MAGIC`—The magic number for the procfs filesystem.
 #[cfg(all(