IoUring: Working on Pipe2 flags

Build on the extensive work already done

IoUring: add fixed_fd_install, ftruncate, cmd_discard

Working on IoUring pipe flags

Signed-off-by: Bernard Assan <mega.alpha100@gmail.com>

lib/std/os/linux.zig

@@ -494,6 +494,161 @@ pub const O = switch (native_arch) {
     else => @compileError("missing std.os.linux.O constants for this architecture"),
 };
 
+pub const Pipe2 = switch (native_arch) {
+    .x86_64, .x86, .riscv32, .riscv64, .loongarch64 => packed struct(u32) {
+        _: u7 = 0,
+        EXCL: bool = false, //
+        _9: u3 = 0,
+        NONBLOCK: bool = false, //
+        _13: u2 = 0,
+        DIRECT: bool = false, //
+        _16: u4 = 0,
+        CLOEXEC: bool = false, //
+        _21: u12 = 0,
+    },
+    .aarch64, .aarch64_be, .arm, .armeb, .thumb, .thumbeb => packed struct(u32) {
+        ACCMODE: ACCMODE = .RDONLY,
+        _2: u4 = 0,
+        CREAT: bool = false,
+        EXCL: bool = false, //
+        NOCTTY: bool = false,
+        TRUNC: bool = false,
+        APPEND: bool = false,
+        NONBLOCK: bool = false, //
+        DSYNC: bool = false,
+        ASYNC: bool = false,
+        DIRECTORY: bool = false,
+        NOFOLLOW: bool = false,
+        DIRECT: bool = false, //
+        LARGEFILE: bool = false,
+        NOATIME: bool = false,
+        CLOEXEC: bool = false, //
+        SYNC: bool = false,
+        PATH: bool = false,
+        TMPFILE: bool = false,
+        _23: u9 = 0,
+    },
+    .sparc64 => packed struct(u32) {
+        ACCMODE: ACCMODE = .RDONLY,
+        _2: u1 = 0,
+        APPEND: bool = false,
+        _4: u2 = 0,
+        ASYNC: bool = false,
+        _7: u2 = 0,
+        CREAT: bool = false,
+        TRUNC: bool = false,
+        EXCL: bool = false, //
+        _12: u1 = 0,
+        DSYNC: bool = false,
+        NONBLOCK: bool = false, //
+        NOCTTY: bool = false,
+        DIRECTORY: bool = false,
+        NOFOLLOW: bool = false,
+        _18: u2 = 0,
+        DIRECT: bool = false, //
+        NOATIME: bool = false,
+        CLOEXEC: bool = false, //
+        SYNC: bool = false,
+        PATH: bool = false,
+        TMPFILE: bool = false,
+        _27: u6 = 0,
+    },
+    .mips, .mipsel, .mips64, .mips64el => packed struct(u32) {
+        ACCMODE: ACCMODE = .RDONLY,
+        _2: u1 = 0,
+        APPEND: bool = false,
+        DSYNC: bool = false,
+        _5: u2 = 0,
+        NONBLOCK: bool = false, //
+        CREAT: bool = false,
+        TRUNC: bool = false,
+        EXCL: bool = false, //
+        NOCTTY: bool = false,
+        ASYNC: bool = false,
+        LARGEFILE: bool = false,
+        SYNC: bool = false,
+        DIRECT: bool = false, //
+        DIRECTORY: bool = false,
+        NOFOLLOW: bool = false,
+        NOATIME: bool = false, //
+        CLOEXEC: bool = false,
+        _20: u1 = 0,
+        PATH: bool = false,
+        TMPFILE: bool = false,
+        _23: u9 = 0,
+    },
+    .powerpc, .powerpcle, .powerpc64, .powerpc64le => packed struct(u32) {
+        ACCMODE: ACCMODE = .RDONLY,
+        _2: u4 = 0,
+        CREAT: bool = false,
+        EXCL: bool = false, //
+        NOCTTY: bool = false,
+        TRUNC: bool = false,
+        APPEND: bool = false,
+        NONBLOCK: bool = false, //
+        DSYNC: bool = false,
+        ASYNC: bool = false,
+        DIRECTORY: bool = false,
+        NOFOLLOW: bool = false,
+        LARGEFILE: bool = false,
+        DIRECT: bool = false, //
+        NOATIME: bool = false,
+        CLOEXEC: bool = false, //
+        SYNC: bool = false,
+        PATH: bool = false,
+        TMPFILE: bool = false,
+        _23: u9 = 0,
+    },
+    .hexagon, .or1k, .s390x => packed struct(u32) {
+        ACCMODE: ACCMODE = .RDONLY,
+        _2: u4 = 0,
+        CREAT: bool = false,
+        EXCL: bool = false, //
+        NOCTTY: bool = false,
+        TRUNC: bool = false,
+        APPEND: bool = false,
+        NONBLOCK: bool = false, //
+        DSYNC: bool = false,
+        ASYNC: bool = false,
+        DIRECT: bool = false, //
+        LARGEFILE: bool = false,
+        DIRECTORY: bool = false,
+        NOFOLLOW: bool = false,
+        NOATIME: bool = false,
+        CLOEXEC: bool = false, //
+        _20: u1 = 0,
+        PATH: bool = false,
+        _22: u10 = 0,
+
+        // #define O_RSYNC    04010000
+        // #define O_SYNC     04010000
+        // #define O_TMPFILE 020200000
+        // #define O_NDELAY O_NONBLOCK
+    },
+    .m68k => packed struct(u32) {
+        ACCMODE: ACCMODE = .RDONLY,
+        _2: u4 = 0,
+        CREAT: bool = false,
+        EXCL: bool = false, //
+        NOCTTY: bool = false,
+        TRUNC: bool = false,
+        APPEND: bool = false,
+        NONBLOCK: bool = false, //
+        DSYNC: bool = false,
+        ASYNC: bool = false,
+        DIRECTORY: bool = false,
+        NOFOLLOW: bool = false,
+        DIRECT: bool = false, //
+        LARGEFILE: bool = false,
+        NOATIME: bool = false,
+        CLOEXEC: bool = false, //
+        _20: u1 = 0,
+        PATH: bool = false,
+        _22: u10 = 0,
+    },
+    else => @compileError("missing std.os.linux.O constants for this architecture"),
+};
+
 /// Set by startup code, used by `getauxval`.
 pub var elf_aux_maybe: ?[*]std.elf.Auxv = null;
 
@@ -745,7 +900,6 @@ pub fn futex_4arg(uaddr: *const u32, futex_op: FUTEX_OP, val: u32, timeout: ?*co
 /// most recently woken, nor...)
 ///
 /// Requires at least kernel v5.16.
-// TODO: can't we use slices here? and assert `Futex2.waitone_max`
 pub fn futex2_waitv(
     /// The length of `futexes` slice must not exceed `Futex2.waitone_max`
     futexes: []const Futex2.WaitOne,
@@ -3757,8 +3911,11 @@ pub const Futex2 = struct {
 
         /// `Bitset` with all bits set for the FUTEX_xxx_BITSET OPs to request a
         /// match of any bit. matches FUTEX_BITSET_MATCH_ANY
-        pub const match_any: Bitset = @bitCast(@as(u64, 0x00000000ffffffff));
+        pub const match_any: Bitset = @bitCast(@as(u64, 0x0000_0000_ffff_ffff));
-        /// Bitset must not be empty, this is only useful in test
+        /// An empty `Bitset` will not wake any threads because the kernel
+        /// requires at least one bit to be set in the bitmask to identify
+        /// which waiters should be woken up. Therefore, no action will be
+        /// taken if the bitset is zero, this is only useful in test
         pub const empty: Bitset = .{};
 
         /// Create from raw u64 value

lib/std/os/linux/IoUring.zig

@@ -1806,7 +1806,6 @@ pub fn futex_wait(
     return sqe;
 }
 
-// TODO: ensure flags and Wait in futexv are correct
 /// Available since kernel 6.7
 pub fn futex_waitv(
     self: *IoUring,
@@ -1821,6 +1820,55 @@ pub fn futex_waitv(
     return sqe;
 }
 
+pub fn fixed_fd_install(
+    self: *IoUring,
+    user_data: u64,
+    fd: linux.fd_t,
+    flags: uflags.FixedFd,
+) !*Sqe {
+    const sqe = try self.get_sqe();
+    sqe.prep_fixed_fd_install(fd, flags);
+    sqe.user_data = user_data;
+    return sqe;
+}
+
+pub fn ftruncate(
+    self: *IoUring,
+    user_data: u64,
+    fd: linux.fd_t,
+    offset: u64,
+) !*Sqe {
+    const sqe = try self.get_sqe();
+    sqe.prep_ftruncate(fd, offset);
+    sqe.user_data = user_data;
+    return sqe;
+}
+
+pub fn cmd_discard(
+    self: *IoUring,
+    user_data: u64,
+    fd: linux.fd_t,
+    offset: u64,
+    nbytes: u64,
+) !*Sqe {
+    const sqe = try self.get_sqe();
+    sqe.prep_cmd_discard(fd, offset, nbytes);
+    sqe.user_data = user_data;
+    return sqe;
+}
+
+pub fn pipe(
+    self: *IoUring,
+    user_data: u64,
+    fds: *[2]linux.fd_t,
+    flags: uflags.,
+) !*Sqe {
+    const sqe = try self.get_sqe();
+    sqe.prep_pipe(fds, offset, nbytes);
+    sqe.user_data = user_data;
+    return sqe;
+}
+
 pub fn register_buffers_sparse(self: *IoUring, nr: u32) !void {
     assert(self.fd >= 0);
 
@@ -2332,7 +2380,7 @@ pub const Sqe = extern struct {
     /// msg_flags | timeout_flags | accept_flags | cancel_flags | open_flags |
     /// statx_flags | fadvise_advice | splice_flags | rename_flags |
     /// unlink_flags | hardlink_flags xattr_flags | msg_ring_flags |
-    /// uring_cmd_flags | waitid_flags | futex_flags install_fd_flags |
+    /// uring_cmd_flags | waitid_flags | futex_flags | install_fd_flags |
     /// nop_flags | pipe_flags
     rw_flags: u32,
     /// data to be passed back at completion time
@@ -3323,6 +3371,73 @@ pub const Sqe = extern struct {
         sqe.rw_flags = flags;
     }
 
+    pub fn prep_fixed_fd_install(
+        sqe: *Sqe,
+        fd: linux.fd_t,
+        flags: uflags.FixedFd,
+    ) void {
+        sqe.prep_rw(
+            .fixed_fd_install,
+            fd,
+            undefined,
+            0,
+            0,
+        );
+        sqe.flags = .{ .fixed_file = true };
+        sqe.rw_flags = @bitCast(flags);
+    }
+
+    pub fn prep_ftruncate(
+        sqe: *Sqe,
+        fd: linux.fd_t,
+        offset: u64,
+    ) void {
+        sqe.prep_rw(
+            .ftruncate,
+            fd,
+            undefined,
+            0,
+            offset,
+        );
+    }
+
+    pub fn prep_cmd_discard(
+        sqe: *Sqe,
+        fd: linux.fd_t,
+        offset: u64,
+        nbytes: u64,
+    ) void {
+        sqe.prep_rw(
+            .uring_cmd,
+            fd,
+            undefined,
+            0,
+            0,
+        );
+        // sqe.off maps to sqe.cmd_op in liburing
+        sqe.off = constants.BLOCK_URING_CMD_DISCARD;
+        sqe.addr = offset;
+        sqe.addr3 = nbytes;
+    }
+
+    pub fn prep_pipe(
+        sqe: *Sqe,
+        fd: linux.fd_t,
+        offset: u64,
+        nbytes: u64,
+    ) void {
+        sqe.prep_rw(
+            .uring_cmd,
+            fd,
+            undefined,
+            0,
+            0,
+        );
+        // sqe.off maps to sqe.cmd_op in liburing
+        sqe.off = constants.BLOCK_URING_CMD_DISCARD;
+        sqe.addr = offset;
+        sqe.addr3 = nbytes;
+    }
     // TODO: maybe remove unused flag fields?
     pub fn prep_bind(
         sqe: *Sqe,
@@ -4143,6 +4258,10 @@ pub const ZcrxIfqRegister = extern struct {
 
 // COMMIT: move IoUring constants to Constants
 pub const constants = struct {
+    /// io_uring block file commands, see IORING_OP_URING_CMD.
+    /// It's a different number space from ioctl(), reuse the block's code 0x12.
+    /// It is the value of ioctl.IO(0x12, 0) at runtime
+    pub const BLOCK_URING_CMD_DISCARD = 0x1200;
     /// If sqe.file_index (splice_fd_in in Zig Struct) is set to this for
     /// opcodes that instantiate a new an available direct descriptor instead
     /// of having the application pass one direct descriptor