diff --git a/lib/std/io/test.zig b/lib/std/io/test.zig index 92259fd6e9..d6de912240 100644 --- a/lib/std/io/test.zig +++ b/lib/std/io/test.zig @@ -649,3 +649,16 @@ test "updateTimes" { std.testing.expect(stat_new.atime < stat_old.atime); std.testing.expect(stat_new.mtime < stat_old.mtime); } + +test "memfd_create" { + if (builtin.os != .linux) return error.SkipZigTest; + + const fd = try std.os.memfd_create("test", 0); + try std.os.write(fd, "test"); + try std.os.lseek_SET(fd, 0); + + var buf: [10]u8 = undefined; + const bytes_read = try std.os.read(fd, &buf); + expect(bytes_read == 4); + expect(mem.eql(u8, buf[0..4], "test")); +} diff --git a/lib/std/os.zig b/lib/std/os.zig index f7426faeda..37043f19bb 100644 --- a/lib/std/os.zig +++ b/lib/std/os.zig @@ -3281,3 +3281,35 @@ pub fn setsockopt(fd: fd_t, level: u32, optname: u32, opt: []const u8) SetSockOp else => |err| return unexpectedErrno(err), } } + +// TODO support for non-null terminated strings? +pub fn memfd_createC(name: [*:0]const u8, flags: usize) !fd_t { + if (builtin.os != .linux) @compileError("memfd_create() not implemented for this target"); + + const rc = linux.memfd_create(name, flags); + switch (linux.getErrno(rc)) { + 0 => return @intCast(fd_t, rc), + EFAULT => unreachable, // name has invalid memory + EINVAL => unreachable, // name/flags are faulty + ENFILE => return error.SystemFdQuotaExceeded, + EMFILE => return error.ProcessFdQuotaExceeded, + ENOMEM => return error.OutOfMemory, + else => |err| return unexpectedErrno(err), + } +} + +pub const MFD_NAME_PREFIX = "memfd:"; +pub const MFD_MAX_NAME_LEN = NAME_MAX - MFD_NAME_PREFIX.len; +fn toMemFdPath(name: []const u8) ![MFD_MAX_NAME_LEN:0]u8 { + var path_with_null: [MFD_MAX_NAME_LEN:0]u8 = undefined; + // >= rather than > to make room for the null byte + if (name.len >= MFD_MAX_NAME_LEN) return error.NameTooLong; + mem.copy(u8, &path_with_null, name); + path_with_null[name.len] = 0; + return path_with_null; +} + +pub fn memfd_create(name: []const u8, flags: usize) !fd_t { + const name_t = try toMemFdPath(name); + return try memfd_createC(&name_t, flags); +} diff --git a/lib/std/os/bits/linux.zig b/lib/std/os/bits/linux.zig index 8033f27c2b..3fb160e3ec 100644 --- a/lib/std/os/bits/linux.zig +++ b/lib/std/os/bits/linux.zig @@ -26,6 +26,7 @@ pub const uid_t = i32; pub const gid_t = u32; pub const clock_t = isize; +pub const NAME_MAX = 255; pub const PATH_MAX = 4096; pub const IOV_MAX = 1024; @@ -1417,3 +1418,38 @@ pub const POLLHUP = 0x010; pub const POLLNVAL = 0x020; pub const POLLRDNORM = 0x040; pub const POLLRDBAND = 0x080; + +pub const MFD_CLOEXEC = 0x0001; +pub const MFD_ALLOW_SEALING = 0x0002; +pub const MFD_HUGETLB = 0x0004; +pub const MFD_ALL_FLAGS = MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB; + +pub const HUGETLB_FLAG_ENCODE_SHIFT = 26; +pub const HUGETLB_FLAG_ENCODE_MASK = 0x3f; +pub const HUGETLB_FLAG_ENCODE_64KB = 16 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_512KB = 19 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_1MB = 20 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_2MB = 21 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_8MB = 23 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_16MB = 24 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_32MB = 25 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_256MB = 28 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_512MB = 29 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_1GB = 30 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_2GB = 31 << HUGETLB_FLAG_ENCODE_SHIFT; +pub const HUGETLB_FLAG_ENCODE_16GB = 34 << HUGETLB_FLAG_ENCODE_SHIFT; + +pub const MFD_HUGE_SHIFT = HUGETLB_FLAG_ENCODE_SHIFT; +pub const MFD_HUGE_MASK = HUGETLB_FLAG_ENCODE_MASK; +pub const MFD_HUGE_64KB = HUGETLB_FLAG_ENCODE_64KB; +pub const MFD_HUGE_512KB = HUGETLB_FLAG_ENCODE_512KB; +pub const MFD_HUGE_1MB = HUGETLB_FLAG_ENCODE_1MB; +pub const MFD_HUGE_2MB = HUGETLB_FLAG_ENCODE_2MB; +pub const MFD_HUGE_8MB = HUGETLB_FLAG_ENCODE_8MB; +pub const MFD_HUGE_16MB = HUGETLB_FLAG_ENCODE_16MB; +pub const MFD_HUGE_32MB = HUGETLB_FLAG_ENCODE_32MB; +pub const MFD_HUGE_256MB = HUGETLB_FLAG_ENCODE_256MB; +pub const MFD_HUGE_512MB = HUGETLB_FLAG_ENCODE_512MB; +pub const MFD_HUGE_1GB = HUGETLB_FLAG_ENCODE_1GB; +pub const MFD_HUGE_2GB = HUGETLB_FLAG_ENCODE_2GB; +pub const MFD_HUGE_16GB = HUGETLB_FLAG_ENCODE_16GB; diff --git a/lib/std/os/linux.zig b/lib/std/os/linux.zig index d5bab64493..69e5b25f86 100644 --- a/lib/std/os/linux.zig +++ b/lib/std/os/linux.zig @@ -1110,6 +1110,10 @@ pub fn io_uring_register(fd: i32, opcode: u32, arg: ?*const c_void, nr_args: u32 return syscall4(SYS_io_uring_register, @bitCast(usize, @as(isize, fd)), opcode, @ptrToInt(arg), nr_args); } +pub fn memfd_create(name: [*:0]const u8, flags: usize) usize { + return syscall2(SYS_memfd_create, @ptrToInt(name), flags); +} + test "" { if (builtin.os == .linux) { _ = @import("linux/test.zig");