diff --git a/src/kernel/filesystem/vfs.zig b/src/kernel/filesystem/vfs.zig index 8a906b0..fce16a6 100644 --- a/src/kernel/filesystem/vfs.zig +++ b/src/kernel/filesystem/vfs.zig @@ -211,13 +211,8 @@ pub const DirNode = struct { /// See the documentation for FileSystem.Open pub fn open(self: *const DirNode, name: []const u8, flags: OpenFlags, args: OpenArgs) (Allocator.Error || Error)!*Node { - var fs = self.fs; - var node = self; - if (self.mount) |mnt| { - fs = mnt.fs; - node = mnt; - } - return fs.open(fs, node, name, flags, args); + var node = self.mount orelse self; + return node.fs.open(node.fs, node, name, flags, args); } /// See the documentation for FileSystem.Close @@ -426,6 +421,20 @@ pub fn open(path: []const u8, follow_symlinks: bool, flags: OpenFlags, args: Ope return try traversePath(path, follow_symlinks, flags, args); } +/// +/// Close a node. +/// +/// Arguments: +/// IN node: Node - The node to close +/// +pub fn close(node: Node) void { + switch (node) { + .Dir => |d| d.close(), + .File => |f| f.close(), + .Symlink => |s| s.close(), + } +} + /// /// Open a file at a path. /// @@ -592,7 +601,7 @@ const TestFS = struct { const Self = @This(); - fn deinit(self: *@This()) void { + pub fn deinit(self: *@This()) void { self.tree.deinit(self.allocator); self.allocator.destroy(self.fs); } @@ -718,7 +727,7 @@ const TestFS = struct { } }; -fn testInitFs(allocator: Allocator) !*TestFS { +pub fn testInitFs(allocator: Allocator) !*TestFS { const fs = try allocator.create(FileSystem); var testfs = try allocator.create(TestFS); var root_node = try allocator.create(Node); diff --git a/src/kernel/kmain.zig b/src/kernel/kmain.zig index 8d2ab82..d6cd618 100644 --- a/src/kernel/kmain.zig +++ b/src/kernel/kmain.zig @@ -17,6 +17,7 @@ const scheduler = @import("scheduler.zig"); const vfs = @import("filesystem/vfs.zig"); const initrd = @import("filesystem/initrd.zig"); const keyboard = @import("keyboard.zig"); +const syscalls = @import("syscalls.zig"); const Allocator = std.mem.Allocator; comptime { @@ -96,6 +97,7 @@ export fn kmain(boot_payload: arch.BootPayload) void { panic_root.panic(@errorReturnTrace(), "Failed to initialise kernel heap: {}\n", .{e}); }; + syscalls.init(kernel_heap.allocator()); tty.init(kernel_heap.allocator(), boot_payload); var arch_kb = keyboard.init(fixed_allocator.allocator()) catch |e| { panic_root.panic(@errorReturnTrace(), "Failed to inititalise keyboard: {}\n", .{e}); diff --git a/src/kernel/scheduler.zig b/src/kernel/scheduler.zig index 5dc68a1..852823d 100644 --- a/src/kernel/scheduler.zig +++ b/src/kernel/scheduler.zig @@ -27,7 +27,7 @@ extern var KERNEL_STACK_START: []u32; extern var KERNEL_STACK_END: []u32; /// The current task running -var current_task: *Task = undefined; +pub var current_task: *Task = undefined; /// Array list of all runnable tasks var tasks: TailQueue(*Task) = undefined; diff --git a/src/kernel/syscalls.zig b/src/kernel/syscalls.zig index bb25793..ddec609 100644 --- a/src/kernel/syscalls.zig +++ b/src/kernel/syscalls.zig @@ -1,14 +1,99 @@ const std = @import("std"); +const testing = std.testing; +const is_test = @import("builtin").is_test; const scheduler = @import("scheduler.zig"); const panic = @import("panic.zig").panic; const log = std.log.scoped(.syscalls); const arch = @import("arch.zig").internals; +const vfs = @import("filesystem/vfs.zig"); +const task = @import("task.zig"); +const vmm = @import("vmm.zig"); +const mem = @import("mem.zig"); +const pmm = @import("pmm.zig"); +const bitmap = @import("bitmap.zig"); -/// A compilation of all errors that syscall handlers could return. -pub const Error = error{OutOfMemory}; +var allocator: std.mem.Allocator = undefined; + +/// The maximum amount of data to allocate when copying user memory into kernel memory +pub const USER_MAX_DATA_LEN = 16 * 1024; + +pub const Error = error{ NoMoreFSHandles, TooBig, NotAFile }; /// All implemented syscalls pub const Syscall = enum { + /// Open a new vfs node + /// + /// Arguments: + /// path_ptr: usize - The user/kernel pointer to the file path to open + /// path_len: usize - The length of the file path + /// flags: usize - The flag specifying what to do with the opened node. Use the integer value of vfs.OpenFlags + /// args: usize - The user/kernel pointer to the structure holding the vfs.OpenArgs + /// ignored: usize - Ignored + /// + /// Return: usize + /// The handle for the opened vfs node + /// + /// Error: + /// NoMoreFSHandles - The task has reached the maximum number of allowed vfs handles + /// OutOfMemory - There wasn't enough kernel (heap or VMM) memory left to fulfill the request. + /// TooBig - The path length is greater than allowed + /// InvalidAddress - A pointer that the user task passed is invalid (not mapped, out of bounds etc.) + /// InvalidFlags - The flags provided don't correspond to a vfs.OpenFlags value + /// Refer to vfs.Error for details on what causes vfs errors + /// + Open, + + /// Read data from an open vfs file + /// + /// Arguments: + /// node_handle: usize - The file handle returned from the open syscall + /// buff_ptr: usize ` - The user/kernel address of the buffer to put the read data in + /// buff_len: usize - The size of the buffer + /// ignored1: usize - Ignored + /// ignored2: usize - Ignored + /// + /// Return: usize + /// The number of bytes read and put into the buffer + /// + /// Error: + /// OutOfBounds - The node handle is outside of the maximum per process + /// TooBig - The buffer is bigger than what a user process is allowed to give the kernel + /// NotAFile - The handle does not correspond to a file + /// Refer to vfs.FileNode.read and vmm.VirtualMemoryManager.copyData for details on what causes other errors + /// + Read, + /// Write data from to open vfs file + /// + /// Arguments: + /// node_handle: usize - The file handle returned from the open syscall + /// buff_ptr: usize ` - The user/kernel address of the buffer containing the data to write + /// buff_len: usize - The size of the buffer + /// ignored1: usize - Ignored + /// ignored2: usize - Ignored + /// + /// Return: usize + /// The number of bytes written + /// + /// Error: + /// OutOfBounds - The node handle is outside of the maximum per process + /// TooBig - The buffer is bigger than what a user process is allowed to give the kernel + /// NotAFile - The handle does not correspond to a file + /// Refer to vfs.FileNode.read and vmm.VirtualMemoryManager.copyData for details on what causes other errors + /// + Write, + /// + /// Close an open vfs node. What it means to "close" depends on the underlying file system, but often it will cause the file to be committed to disk or for a network socket to be closed + /// + /// Arguments: + /// node_handle: usize - The handle to close + /// ignored1..4: usize - Ignored + /// + /// Return: void + /// + /// Error: + /// OutOfBounds - The node handle is outside of the maximum per process + /// NotOpened - The node handle hasn't been opened + Close, Test1, Test2, Test3, @@ -24,6 +109,10 @@ pub const Syscall = enum { /// fn getHandler(self: @This()) Handler { return switch (self) { + .Open => handleOpen, + .Read => handleRead, + .Write => handleWrite, + .Close => handleClose, .Test1 => handleTest1, .Test2 => handleTest2, .Test3 => handleTest3, @@ -42,21 +131,26 @@ pub const Syscall = enum { pub fn isTest(self: @This()) bool { return switch (self) { .Test1, .Test2, .Test3 => true, + else => false, }; } }; /// A function that can handle a syscall and return a result or an error -pub const Handler = fn (ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) Error!usize; +pub const Handler = fn (ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) anyerror!usize; + +pub fn init(alloc: std.mem.Allocator) void { + allocator = alloc; +} /// -/// Convert an error code to an instance of Error. The conversion must be synchronised with toErrorCode +/// Convert an error code to an instance of anyerror. The conversion must be synchronised with toErrorCode /// Passing an error code that does not correspond to an error results in safety-protected undefined behaviour /// /// Arguments: /// IN code: u16 - The erorr code to convert /// -/// Return: Error +/// Return: anyerror /// The error corresponding to the error code /// pub fn fromErrorCode(code: u16) anyerror { @@ -64,10 +158,10 @@ pub fn fromErrorCode(code: u16) anyerror { } /// -/// Convert an instance of Error to an error code. The conversion must be synchronised with fromErrorCode +/// Convert an instance of anyerror to an error code. The conversion must be synchronised with fromErrorCode /// /// Arguments: -/// IN err: Error - The erorr to convert +/// IN err: anyerror - The erorr to convert /// /// Return: u16 /// The error code corresponding to the error @@ -86,14 +180,223 @@ pub fn toErrorCode(err: anyerror) u16 { /// Return: usize /// The syscall result /// -/// Error: Error +/// Error: anyerror /// The error raised by the handler /// -pub fn handle(syscall: Syscall, ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) Error!usize { +pub fn handle(syscall: Syscall, ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) anyerror!usize { return try syscall.getHandler()(ctx, arg1, arg2, arg3, arg4, arg5); } -pub fn handleTest1(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) Error!usize { +/// +/// Get a slice containing the data at an address and length. If the current task is a kernel task then a simple pointer to slice conversion is performed, +/// otherwise the slice is allocated on the heap and the data is copied in from user space. +/// +/// Arguments: +/// IN ptr: usize - The slice's address +/// IN len: usize - The number of bytes +/// +/// Error: Error || Allocator.Error || VmmError || BitmapError +/// OutOfMemory - There wasn't enough kernel (heap or VMM) memory left to fulfill the request. +/// TooBig - The user task requested to have too much data copied +/// NotAllocated - The pointer hasn't been mapped by the task +/// OutOfBounds - The pointer and length is out of bounds of the task's VMM +/// +/// Return: []u8 +/// The slice of data. Will be stack-allocated if the current task is kernel-level, otherwise will be heap-allocated +/// +fn getData(ptr: usize, len: usize) (Error || std.mem.Allocator.Error || vmm.VmmError || bitmap.BitmapError)![]u8 { + if (scheduler.current_task.kernel) { + if (try vmm.kernel_vmm.isSet(ptr)) { + return @intToPtr([*]u8, ptr)[0..len]; + } else { + return error.NotAllocated; + } + } else { + if (len > USER_MAX_DATA_LEN) { + return Error.TooBig; + } + var buff = try allocator.alloc(u8, len); + errdefer allocator.free(buff); + try vmm.kernel_vmm.copyData(scheduler.current_task.vmm, false, buff, ptr); + return buff; + } +} + +/// Open a new vfs node +/// +/// Arguments: +/// path_ptr: usize - The user/kernel pointer to the file path to open +/// path_len: usize - The length of the file path +/// flags: usize - The flag specifying what to do with the opened node. Use the integer value of vfs.OpenFlags +/// args: usize - The user/kernel pointer to the structure holding the vfs.OpenArgs +/// ignored: usize - Ignored +/// +/// Return: usize +/// The handle for the opened vfs node +/// +/// Error: +/// NoMoreFSHandles - The task has reached the maximum number of allowed vfs handles +/// OutOfMemory - There wasn't enough kernel (heap or VMM) memory left to fulfill the request. +/// TooBig - The path length is greater than allowed +/// InvalidAddress - A pointer that the user task passed is invalid (not mapped, out of bounds etc.) +/// InvalidFlags - The flags provided don't correspond to a vfs.OpenFlags value +/// Refer to vfs.Error for details on what causes vfs errors +/// +fn handleOpen(ctx: *const arch.CpuState, path_ptr: usize, path_len: usize, flags: usize, args: usize, ignored: usize) anyerror!usize { + _ = ctx; + _ = ignored; + const current_task = scheduler.current_task; + if (!current_task.hasFreeVFSHandle()) { + return Error.NoMoreFSHandles; + } + + // Fetch the open arguments from user/kernel memory + var open_args: vfs.OpenArgs = if (args == 0) .{} else blk: { + const data = try getData(args, @sizeOf(vfs.OpenArgs)); + defer if (!current_task.kernel) allocator.free(data); + break :blk std.mem.bytesAsValue(vfs.OpenArgs, data[0..@sizeOf(vfs.OpenArgs)]).*; + }; + // The symlink target could refer to a location in user memory so convert that too + if (open_args.symlink_target) |target| { + open_args.symlink_target = try getData(@ptrToInt(target.ptr), target.len); + } + defer if (!current_task.kernel) if (open_args.symlink_target) |target| allocator.free(target); + + const open_flags = std.meta.intToEnum(vfs.OpenFlags, flags) catch return error.InvalidFlags; + const path = try getData(path_ptr, path_len); + defer if (!current_task.kernel) allocator.free(path); + + const node = try vfs.open(path, true, open_flags, open_args); + errdefer vfs.close(node.*); + return (try current_task.addVFSHandle(node)) orelse panic(null, "Failed to add a VFS handle to current_task\n", .{}); +} + +/// Read data from an open vfs file +/// +/// Arguments: +/// node_handle: usize - The file handle returned from the open syscall +/// buff_ptr: usize ` - The user/kernel address of the buffer to put the read data in +/// buff_len: usize - The size of the buffer +/// ignored1: usize - Ignored +/// ignored2: usize - Ignored +/// +/// Return: usize +/// The number of bytes read and put into the buffer +/// +/// Error: +/// OutOfBounds - The node handle is outside of the maximum per process +/// TooBig - The buffer is bigger than what a user process is allowed to give the kernel +/// NotAFile - The handle does not correspond to a file +/// NotOpened - The handle doesn't correspond to an opened file +/// Refer to vfs.FileNode.read and vmm.VirtualMemoryManager.copyData for details on what causes other errors +/// +fn handleRead(ctx: *const arch.CpuState, node_handle: usize, buff_ptr: usize, buff_len: usize, ignored1: usize, ignored2: usize) anyerror!usize { + _ = ctx; + _ = ignored1; + _ = ignored2; + if (node_handle >= task.VFS_HANDLES_PER_PROCESS) + return error.OutOfBounds; + const real_handle = @intCast(task.Handle, node_handle); + if (buff_len > USER_MAX_DATA_LEN) { + return Error.TooBig; + } + + const current_task = scheduler.current_task; + const node_opt = current_task.getVFSHandle(real_handle) catch panic(@errorReturnTrace(), "Failed to get VFS node for handle {}\n", .{real_handle}); + if (node_opt) |node| { + const file = switch (node.*) { + .File => |*f| f, + else => return error.NotAFile, + }; + var buff = if (current_task.kernel) @intToPtr([*]u8, buff_ptr)[0..buff_len] else try allocator.alloc(u8, buff_len); + defer if (!current_task.kernel) allocator.free(buff); + + const bytes_read = try file.read(buff); + // TODO: A more performant method would be mapping in the user memory and using that directly. Then we wouldn't need to allocate or copy the buffer + if (!current_task.kernel) try vmm.kernel_vmm.copyData(current_task.vmm, true, buff, buff_ptr); + return bytes_read; + } + + return error.NotOpened; +} + +/// Write data from to open vfs file +/// +/// Arguments: +/// node_handle: usize - The file handle returned from the open syscall +/// buff_ptr: usize ` - The user/kernel address of the buffer containing the data to write +/// buff_len: usize - The size of the buffer +/// ignored1: usize - Ignored +/// ignored2: usize - Ignored +/// +/// Return: usize +/// The number of bytes written +/// +/// Error: +/// OutOfBounds - The node handle is outside of the maximum per process +/// TooBig - The buffer is bigger than what a user process is allowed to give the kernel +/// NotAFile - The handle does not correspond to a file +/// NotOpened - The handle doesn't correspond to an opened file +/// Refer to vfs.FileNode.read and vmm.VirtualMemoryManager.copyData for details on what causes other errors +/// +fn handleWrite(ctx: *const arch.CpuState, node_handle: usize, buff_ptr: usize, buff_len: usize, ignored1: usize, ignored2: usize) anyerror!usize { + _ = ctx; + _ = ignored1; + _ = ignored2; + if (node_handle >= task.VFS_HANDLES_PER_PROCESS) + return error.OutOfBounds; + const real_handle = @intCast(task.Handle, node_handle); + + const current_task = scheduler.current_task; + const node_opt = current_task.getVFSHandle(real_handle) catch panic(@errorReturnTrace(), "Failed to get VFS node for handle {}\n", .{real_handle}); + if (node_opt) |node| { + const file = switch (node.*) { + .File => |*f| f, + else => return error.NotAFile, + }; + + // TODO: A more performant method would be mapping in the user memory and using that directly. Then we wouldn't need to allocate or copy the buffer + var buff = try getData(buff_ptr, buff_len); + defer if (!current_task.kernel) allocator.free(buff); + return try file.write(buff); + } + + return error.NotOpened; +} + +/// +/// Close an open vfs node. What it means to "close" depends on the underlying file system, but often it will cause the file to be committed to disk or for a network socket to be closed +/// +/// Arguments: +/// node_handle: usize - The handle to close +/// ignored1..4: usize - Ignored +/// +/// Return: void +/// +/// Error: +/// OutOfBounds - The node handle is outside of the maximum per process +/// NotOpened - The node handle hasn't been opened +fn handleClose(ctx: *const arch.CpuState, node_handle: usize, ignored1: usize, ignored2: usize, ignored3: usize, ignored4: usize) anyerror!usize { + _ = ctx; + _ = ignored1; + _ = ignored2; + _ = ignored3; + _ = ignored4; + if (node_handle >= task.VFS_HANDLES_PER_PROCESS) + return error.OutOfBounds; + const real_handle = @intCast(task.Handle, node_handle); + const current_task = scheduler.current_task; + const node_opt = current_task.getVFSHandle(real_handle) catch panic(@errorReturnTrace(), "Failed to get VFS node for handle {}\n", .{real_handle}); + if (node_opt) |node| { + current_task.clearVFSHandle(real_handle) catch |e| return switch (e) { + error.VFSHandleNotSet, error.OutOfBounds => error.NotOpened, + }; + vfs.close(node.*); + } + return error.NotOpened; +} + +pub fn handleTest1(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) anyerror!usize { // Suppress unused variable warnings _ = ctx; _ = arg1; @@ -104,12 +407,12 @@ pub fn handleTest1(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: us return 0; } -pub fn handleTest2(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) Error!usize { +pub fn handleTest2(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) anyerror!usize { _ = ctx; return arg1 + arg2 + arg3 + arg4 + arg5; } -pub fn handleTest3(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) Error!usize { +pub fn handleTest3(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: usize, arg4: usize, arg5: usize) anyerror!usize { // Suppress unused variable warnings _ = ctx; _ = arg1; @@ -117,18 +420,351 @@ pub fn handleTest3(ctx: *const arch.CpuState, arg1: usize, arg2: usize, arg3: us _ = arg3; _ = arg4; _ = arg5; - return std.mem.Allocator.Error.OutOfMemory; + return error.OutOfMemory; +} + +fn testInitMem(comptime num_vmm_entries: usize, alloc: std.mem.Allocator, map_all: bool) !std.heap.FixedBufferAllocator { + // handleOpen requires that the name passed is mapped in the VMM + // Allocate them within a buffer so we know the start and end address to give to the VMM + var buffer = try alloc.alloc(u8, num_vmm_entries * vmm.BLOCK_SIZE); + var fixed_buffer_allocator = std.heap.FixedBufferAllocator.init(buffer[0..]); + + vmm.kernel_vmm = try vmm.VirtualMemoryManager(arch.VmmPayload).init(@ptrToInt(fixed_buffer_allocator.buffer.ptr), @ptrToInt(fixed_buffer_allocator.buffer.ptr) + buffer.len, alloc, arch.VMM_MAPPER, arch.KERNEL_VMM_PAYLOAD); + // The PMM is required as well + const mem_profile = mem.MemProfile{ + .vaddr_end = undefined, + .vaddr_start = undefined, + .physaddr_start = undefined, + .physaddr_end = undefined, + .mem_kb = num_vmm_entries * vmm.BLOCK_SIZE / 1024, + .fixed_allocator = undefined, + .virtual_reserved = &[_]mem.Map{}, + .physical_reserved = &[_]mem.Range{}, + .modules = &[_]mem.Module{}, + }; + pmm.init(&mem_profile, alloc); + // Set the whole VMM space as mapped so all address within the buffer allocator will be considered valid + if (map_all) _ = try vmm.kernel_vmm.alloc(num_vmm_entries, null, .{ .kernel = true, .writable = true, .cachable = true }); + return fixed_buffer_allocator; +} + +fn testDeinitMem(alloc: std.mem.Allocator, buffer_allocator: std.heap.FixedBufferAllocator) void { + alloc.free(buffer_allocator.buffer); + vmm.kernel_vmm.deinit(); + pmm.deinit(); } test "getHandler" { try std.testing.expectEqual(Syscall.Test1.getHandler(), handleTest1); try std.testing.expectEqual(Syscall.Test2.getHandler(), handleTest2); try std.testing.expectEqual(Syscall.Test3.getHandler(), handleTest3); + try std.testing.expectEqual(Syscall.Open.getHandler(), handleOpen); + try std.testing.expectEqual(Syscall.Close.getHandler(), handleClose); + try std.testing.expectEqual(Syscall.Read.getHandler(), handleRead); + try std.testing.expectEqual(Syscall.Write.getHandler(), handleWrite); } test "handle" { const state = arch.CpuState.empty(); try std.testing.expectEqual(@as(usize, 0), try handle(.Test1, &state, 0, 0, 0, 0, 0)); try std.testing.expectEqual(@as(usize, 1 + 2 + 3 + 4 + 5), try handle(.Test2, &state, 1, 2, 3, 4, 5)); - try std.testing.expectError(Error.OutOfMemory, handle(.Test3, &state, 0, 0, 0, 0, 0)); + try std.testing.expectError(error.OutOfMemory, handle(.Test3, &state, 0, 0, 0, 0, 0)); +} + +test "handleOpen" { + allocator = std.testing.allocator; + var testfs = try vfs.testInitFs(allocator); + defer allocator.destroy(testfs); + defer testfs.deinit(); + + testfs.instance = 1; + try vfs.setRoot(testfs.tree.val); + + var fixed_buffer_allocator = try testInitMem(1, allocator, true); + var buffer_allocator = fixed_buffer_allocator.allocator(); + defer testDeinitMem(allocator, fixed_buffer_allocator); + + scheduler.current_task = try task.Task.create(0, true, undefined, allocator, true); + defer scheduler.current_task.destroy(allocator); + var current_task = scheduler.current_task; + + const empty = arch.CpuState.empty(); + + // Creating a file + var name1 = try buffer_allocator.dupe(u8, "/abc.txt"); + var test_handle = @intCast(task.Handle, try handleOpen(&empty, @ptrToInt(name1.ptr), name1.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, undefined)); + var test_node = (try current_task.getVFSHandle(test_handle)).?; + try testing.expectEqual(testfs.tree.children.items.len, 1); + var tree = testfs.tree.children.items[0]; + try testing.expect(tree.val.isFile() and test_node.isFile()); + try testing.expectEqual(&test_node.File, &tree.val.File); + try testing.expect(std.mem.eql(u8, tree.name, "abc.txt")); + try testing.expectEqual(tree.data, null); + try testing.expectEqual(tree.children.items.len, 0); + + // Creating a dir + var name2 = try buffer_allocator.dupe(u8, "/def"); + test_handle = @intCast(task.Handle, try handleOpen(&empty, @ptrToInt(name2.ptr), name2.len, @enumToInt(vfs.OpenFlags.CREATE_DIR), 0, undefined)); + test_node = (try current_task.getVFSHandle(test_handle)).?; + try testing.expectEqual(testfs.tree.children.items.len, 2); + tree = testfs.tree.children.items[1]; + try testing.expect(tree.val.isDir() and test_node.isDir()); + try testing.expectEqual(&test_node.Dir, &tree.val.Dir); + try testing.expect(std.mem.eql(u8, tree.name, "def")); + try testing.expectEqual(tree.data, null); + try testing.expectEqual(tree.children.items.len, 0); + + // Creating a file under a new dir + var name3 = try buffer_allocator.dupe(u8, "/def/ghi.zig"); + test_handle = @intCast(task.Handle, try handleOpen(&empty, @ptrToInt(name3.ptr), name3.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, undefined)); + test_node = (try current_task.getVFSHandle(test_handle)).?; + try testing.expectEqual(testfs.tree.children.items[1].children.items.len, 1); + tree = testfs.tree.children.items[1].children.items[0]; + try testing.expect(tree.val.isFile() and test_node.isFile()); + try testing.expectEqual(&test_node.File, &tree.val.File); + try testing.expect(std.mem.eql(u8, tree.name, "ghi.zig")); + try testing.expectEqual(tree.data, null); + try testing.expectEqual(tree.children.items.len, 0); + + // Opening an existing file + test_handle = @intCast(task.Handle, try handleOpen(&empty, @ptrToInt(name3.ptr), name3.len, @enumToInt(vfs.OpenFlags.NO_CREATION), 0, undefined)); + test_node = (try current_task.getVFSHandle(test_handle)).?; + try testing.expectEqual(testfs.tree.children.items[1].children.items.len, 1); + try testing.expect(test_node.isFile()); + try testing.expectEqual(&test_node.File, &tree.val.File); +} + +test "handleRead" { + allocator = std.testing.allocator; + var testfs = try vfs.testInitFs(allocator); + defer allocator.destroy(testfs); + defer testfs.deinit(); + + testfs.instance = 1; + try vfs.setRoot(testfs.tree.val); + + var fixed_buffer_allocator = try testInitMem(1, allocator, true); + var buffer_allocator = fixed_buffer_allocator.allocator(); + defer testDeinitMem(allocator, fixed_buffer_allocator); + scheduler.current_task = try task.Task.create(0, true, &vmm.kernel_vmm, allocator, true); + defer scheduler.current_task.destroy(allocator); + _ = scheduler.current_task; + + const empty = arch.CpuState.empty(); + + var test_file_path = try buffer_allocator.dupe(u8, "/foo.txt"); + var test_file = @intCast(task.Handle, try handleOpen(&empty, @ptrToInt(test_file_path.ptr), test_file_path.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, undefined)); + var f_data = &testfs.tree.children.items[0].data; + var str = "test123"; + f_data.* = try testing.allocator.dupe(u8, str); + + var buffer: [str.len]u8 = undefined; + { + const length = try handleRead(&empty, test_file, @ptrToInt(&buffer[0]), buffer.len, 0, undefined); + try testing.expect(std.mem.eql(u8, str, buffer[0..length])); + } + + { + const length = try handleRead(&empty, test_file, @ptrToInt(&buffer[0]), buffer.len + 1, 0, undefined); + try testing.expect(std.mem.eql(u8, str, buffer[0..length])); + } + + { + const length = try handleRead(&empty, test_file, @ptrToInt(&buffer[0]), buffer.len + 3, 0, undefined); + try testing.expect(std.mem.eql(u8, str, buffer[0..length])); + } + + { + const length = try handleRead(&empty, test_file, @ptrToInt(&buffer[0]), buffer.len - 1, 0, undefined); + try testing.expect(std.mem.eql(u8, str[0 .. str.len - 1], buffer[0..length])); + } + + { + const length = try handleRead(&empty, test_file, @ptrToInt(&buffer[0]), 0, 0, undefined); + try testing.expect(std.mem.eql(u8, str[0..0], buffer[0..length])); + } + // Try reading from a symlink + var args = try buffer_allocator.create(vfs.OpenArgs); + args.* = vfs.OpenArgs{ .symlink_target = test_file_path }; + var link = try buffer_allocator.dupe(u8, "/link"); + var test_link = @intCast(task.Handle, try handleOpen(&empty, @ptrToInt(link.ptr), link.len, @enumToInt(vfs.OpenFlags.CREATE_SYMLINK), @ptrToInt(args), undefined)); + { + const length = try handleRead(&empty, test_link, @ptrToInt(&buffer[0]), buffer.len, 0, undefined); + try testing.expect(std.mem.eql(u8, str[0..str.len], buffer[0..length])); + } +} + +test "handleRead errors" { + allocator = std.testing.allocator; + var testfs = try vfs.testInitFs(allocator); + { + defer allocator.destroy(testfs); + defer testfs.deinit(); + + testfs.instance = 1; + try vfs.setRoot(testfs.tree.val); + + const empty = arch.CpuState.empty(); + + // The data we pass to handleRead needs to be mapped within the VMM, so we need to know their address + // Allocating the data within a fixed buffer allocator is the best way to know the address of the data + var fixed_buffer_allocator = try testInitMem(3, allocator, true); + var buffer_allocator = fixed_buffer_allocator.allocator(); + defer testDeinitMem(allocator, fixed_buffer_allocator); + + scheduler.current_task = try task.Task.create(0, true, &vmm.kernel_vmm, allocator, true); + defer scheduler.current_task.destroy(allocator); + + // Invalid file handle + try testing.expectError(error.OutOfBounds, handleRead(&empty, task.VFS_HANDLES_PER_PROCESS, 0, 0, 0, 0)); + try testing.expectError(error.OutOfBounds, handleRead(&empty, task.VFS_HANDLES_PER_PROCESS + 1, 0, 0, 0, 0)); + + // Unopened file + try testing.expectError(error.NotOpened, handleRead(&empty, 0, 0, 0, 0, 0)); + try testing.expectError(error.NotOpened, handleRead(&empty, 1, 0, 0, 0, 0)); + try testing.expectError(error.NotOpened, handleRead(&empty, task.VFS_HANDLES_PER_PROCESS - 1, 0, 0, 0, 0)); + + // Reading from a dir + const name = try buffer_allocator.dupe(u8, "/dir"); + const node = try handleOpen(&empty, @ptrToInt(name.ptr), name.len, @enumToInt(vfs.OpenFlags.CREATE_DIR), 0, 0); + try testing.expectError(error.NotAFile, handleRead(&empty, node, 0, 0, 0, 0)); + + // User buffer is too big + const name2 = try buffer_allocator.dupe(u8, "/file.txt"); + const node2 = try handleOpen(&empty, @ptrToInt(name2.ptr), name2.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, 0); + scheduler.current_task.kernel = false; + try testing.expectError(Error.TooBig, handleRead(&empty, node2, 0, USER_MAX_DATA_LEN + 1, 0, 0)); + } + try testing.expect(!testing.allocator_instance.detectLeaks()); +} + +test "handleWrite" { + allocator = std.testing.allocator; + var testfs = try vfs.testInitFs(allocator); + defer allocator.destroy(testfs); + defer testfs.deinit(); + + testfs.instance = 1; + try vfs.setRoot(testfs.tree.val); + + var fixed_buffer_allocator = try testInitMem(1, allocator, true); + var buffer_allocator = fixed_buffer_allocator.allocator(); + defer testDeinitMem(allocator, fixed_buffer_allocator); + + scheduler.current_task = try task.Task.create(0, true, &vmm.kernel_vmm, allocator, true); + defer scheduler.current_task.destroy(allocator); + + const empty = arch.CpuState.empty(); + + // Open test file + const name = try buffer_allocator.dupe(u8, "/abc.txt"); + const node = try handleOpen(&empty, @ptrToInt(name.ptr), name.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, undefined); + + // Write + const data = try buffer_allocator.dupe(u8, "test_data 123"); + const res = try handleWrite(&empty, node, @ptrToInt(data.ptr), data.len, 0, 0); + try testing.expectEqual(res, data.len); + try testing.expectEqualSlices(u8, data, testfs.tree.children.items[0].data.?); + + // Write to a file in a folder + const name2 = try buffer_allocator.dupe(u8, "/dir"); + _ = try handleOpen(&empty, @ptrToInt(name2.ptr), name2.len, @enumToInt(vfs.OpenFlags.CREATE_DIR), 0, undefined); + const name3 = try buffer_allocator.dupe(u8, "/dir/def.txt"); + const node3 = try handleOpen(&empty, @ptrToInt(name3.ptr), name3.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, undefined); + const data2 = try buffer_allocator.dupe(u8, "some more test data!"); + const res2 = try handleWrite(&empty, node3, @ptrToInt(data2.ptr), data2.len, 0, 0); + try testing.expectEqual(res2, data2.len); + try testing.expectEqualSlices(u8, data2, testfs.tree.children.items[1].children.items[0].data.?); +} + +test "handleWrite errors" { + allocator = std.testing.allocator; + var testfs = try vfs.testInitFs(allocator); + { + defer allocator.destroy(testfs); + defer testfs.deinit(); + + testfs.instance = 1; + try vfs.setRoot(testfs.tree.val); + + const empty = arch.CpuState.empty(); + + // The data we pass to handleWrite needs to be mapped within the VMM, so we need to know their address + // Allocating the data within a fixed buffer allocator is the best way to know the address of the data + var fixed_buffer_allocator = try testInitMem(3, allocator, true); + var buffer_allocator = fixed_buffer_allocator.allocator(); + defer testDeinitMem(allocator, fixed_buffer_allocator); + + scheduler.current_task = try task.Task.create(0, true, &vmm.kernel_vmm, allocator, true); + defer scheduler.current_task.destroy(allocator); + + // Invalid file handle + try testing.expectError(error.OutOfBounds, handleWrite(&empty, task.VFS_HANDLES_PER_PROCESS, 0, 0, 0, 0)); + try testing.expectError(error.OutOfBounds, handleWrite(&empty, task.VFS_HANDLES_PER_PROCESS + 1, 0, 0, 0, 0)); + + // Unopened file + try testing.expectError(error.NotOpened, handleWrite(&empty, 0, 0, 0, 0, 0)); + try testing.expectError(error.NotOpened, handleWrite(&empty, 1, 0, 0, 0, 0)); + try testing.expectError(error.NotOpened, handleWrite(&empty, task.VFS_HANDLES_PER_PROCESS - 1, 0, 0, 0, 0)); + + // Writing to a dir + const name = try buffer_allocator.dupe(u8, "/dir"); + const node = try handleOpen(&empty, @ptrToInt(name.ptr), name.len, @enumToInt(vfs.OpenFlags.CREATE_DIR), 0, 0); + try testing.expectError(error.NotAFile, handleWrite(&empty, node, 0, 0, 0, 0)); + + // User buffer is too big + const name2 = try buffer_allocator.dupe(u8, "/file.txt"); + const node2 = try handleOpen(&empty, @ptrToInt(name2.ptr), name2.len, @enumToInt(vfs.OpenFlags.CREATE_FILE), 0, 0); + scheduler.current_task.kernel = false; + try testing.expectError(Error.TooBig, handleWrite(&empty, node2, 0, USER_MAX_DATA_LEN + 1, 0, 0)); + } + try testing.expect(!testing.allocator_instance.detectLeaks()); +} + +test "handleOpen errors" { + allocator = std.testing.allocator; + var testfs = try vfs.testInitFs(allocator); + { + defer allocator.destroy(testfs); + defer testfs.deinit(); + + testfs.instance = 1; + try vfs.setRoot(testfs.tree.val); + + const empty = arch.CpuState.empty(); + + // The data we pass to handleOpen needs to be mapped within the VMM, so we need to know their address + // Allocating the data within a fixed buffer allocator is the best way to know the address of the data + var fixed_buffer_allocator = try testInitMem(3, allocator, false); + var buffer_allocator = fixed_buffer_allocator.allocator(); + defer testDeinitMem(allocator, fixed_buffer_allocator); + + scheduler.current_task = try task.Task.create(0, true, &vmm.kernel_vmm, allocator, true); + defer scheduler.current_task.destroy(allocator); + + // Check opening with no free file handles left + const free_handles = scheduler.current_task.file_handles.num_free_entries; + scheduler.current_task.file_handles.num_free_entries = 0; + try testing.expectError(Error.NoMoreFSHandles, handleOpen(&empty, 0, 0, 0, 0, 0)); + scheduler.current_task.file_handles.num_free_entries = free_handles; + + // Using a path that is too long + scheduler.current_task.kernel = false; + try testing.expectError(Error.TooBig, handleOpen(&empty, 0, USER_MAX_DATA_LEN + 1, 0, 0, 0)); + + // Unallocated user address + const test_alloc = try buffer_allocator.alloc(u8, 1); + // The kernel VMM and task VMM need to have their buffers mapped, so we'll temporarily use the buffer allocator since it operates within a known address space + allocator = buffer_allocator; + try testing.expectError(error.NotAllocated, handleOpen(&empty, @ptrToInt(test_alloc.ptr), 1, 0, 0, 0)); + allocator = std.testing.allocator; + + // Unallocated kernel address + scheduler.current_task.kernel = true; + try testing.expectError(error.NotAllocated, handleOpen(&empty, @ptrToInt(test_alloc.ptr), 1, 0, 0, 0)); + + // Invalid flag enum value + try testing.expectError(error.InvalidFlags, handleOpen(&empty, @ptrToInt(test_alloc.ptr), 1, 999, 0, 0)); + } + try testing.expect(!testing.allocator_instance.detectLeaks()); } diff --git a/src/kernel/task.zig b/src/kernel/task.zig index e60fba9..cb50c32 100644 --- a/src/kernel/task.zig +++ b/src/kernel/task.zig @@ -1,6 +1,7 @@ const std = @import("std"); const expectEqual = std.testing.expectEqual; const expectError = std.testing.expectError; +const expect = std.testing.expect; const builtin = @import("builtin"); const is_test = builtin.is_test; const build_options = @import("build_options"); @@ -11,6 +12,7 @@ const pmm = @import("pmm.zig"); const mem = @import("mem.zig"); const elf = @import("elf.zig"); const bitmap = @import("bitmap.zig"); +const vfs = @import("filesystem/vfs.zig"); const Allocator = std.mem.Allocator; const log = std.log.scoped(.task); @@ -18,6 +20,12 @@ const log = std.log.scoped(.task); /// as we cannot deallocate this. extern var KERNEL_STACK_START: *u32; +/// The number of vfs handles that a process can have +pub const VFS_HANDLES_PER_PROCESS = std.math.maxInt(Handle); + +/// A vfs handle. 65k is probably a good limit for the number of files a task can have open at once so we use u16 as the type +pub const Handle = u16; + /// The function type for the entry point. pub const EntryPoint = usize; @@ -27,11 +35,18 @@ const PidBitmap = bitmap.Bitmap(1024, usize); /// The list of PIDs that have been allocated. var all_pids = PidBitmap.init(1024, null) catch unreachable; +const FileHandleBitmap = bitmap.Bitmap(1024, usize); + /// The default stack size of a task. Currently this is set to a page size. pub const STACK_SIZE: u32 = arch.MEMORY_BLOCK_SIZE / @sizeOf(u32); /// The task control block for storing all the information needed to save and restore a task. pub const Task = struct { + pub const Error = error{ + /// The supplied vfs handle hasn't been allocated + VFSHandleNotSet, + }; + const Self = @This(); /// The unique task identifier @@ -52,6 +67,12 @@ pub const Task = struct { /// The virtual memory manager belonging to the task vmm: *vmm.VirtualMemoryManager(arch.VmmPayload), + /// The list of file handles for this process + file_handles: FileHandleBitmap, + + /// The mapping between file handles and file nodes + file_handle_mapping: std.hash_map.AutoHashMap(Handle, *vfs.Node), + /// /// Create a task. This will allocate a PID and the stack. The stack will be set up as a /// kernel task. As this is a new task, the stack will need to be initialised with the CPU @@ -90,6 +111,8 @@ pub const Task = struct { .stack_pointer = if (!alloc_kernel_stack) 0 else @ptrToInt(&k_stack[STACK_SIZE - 1]), .kernel = kernel, .vmm = task_vmm, + .file_handles = FileHandleBitmap.init(null, null) catch unreachable, + .file_handle_mapping = std.hash_map.AutoHashMap(Handle, *vfs.Node).init(allocator), }; try arch.initTask(task, entry_point, allocator, alloc_kernel_stack); @@ -146,8 +169,97 @@ pub const Task = struct { if (!self.kernel) { allocator.free(self.user_stack); } + self.file_handle_mapping.deinit(); allocator.destroy(self); } + + /// + /// Get the VFS node associated with a VFS handle. + /// + /// Arguments: + /// IN self: *Self - The pointer to self. + /// IN handle: Handle - The handle to get the node for. Must have been returned from addVFSHandle. + /// + /// Return: *vfs.Node + /// The node associated with the handle. + /// + /// Error: bitmap.BitmapError + /// See Bitmap. + /// + pub fn getVFSHandle(self: Self, handle: Handle) bitmap.BitmapError!?*vfs.Node { + return self.file_handle_mapping.get(handle); + } + + /// + /// Check if the task has free handles to allocate. + /// + /// Arguments: + /// IN self: Self - The self. + /// + /// Return: bool + /// True if there are free handles, else false. + /// + pub fn hasFreeVFSHandle(self: Self) bool { + return self.file_handles.num_free_entries > 0; + } + + /// + /// Add a handle associated with a node. The node can later be retrieved with getVFSHandle. + /// + /// Arguments: + /// IN self: *Self - The pointer to self. + /// IN node: *vfs.Node - The node to associate with the returned handle. + /// + /// Return: Handle + /// The handle now associated with the vfs node. + /// + /// Error: std.mem.Allocator.Error + /// + pub fn addVFSHandle(self: *Self, node: *vfs.Node) std.mem.Allocator.Error!?Handle { + if (self.file_handles.setFirstFree()) |handle| { + const real_handle = @intCast(Handle, handle); + try self.file_handle_mapping.put(real_handle, node); + return real_handle; + } + return null; + } + + /// + /// Check if the task has a certain handle registered. + /// + /// Arguments: + /// IN self: Self - The self. + /// IN handle: Handle - The handle to check. + /// + /// Return: bool + /// True if the handle has been registered to this task, else false. + /// + /// Error: bitmap.BitmapError + /// See Bitmap. + /// + pub fn hasVFSHandle(self: Self, handle: Handle) bitmap.BitmapError!bool { + return self.file_handles.isSet(handle); + } + + /// + /// Clear a registered handle and de-associate the node from it. + /// + /// Arguments: + /// IN self: *Self - The pointer to self. + /// IN handle: Handle - The handle to clear. Must have been registered before. + /// + /// Error: bitmap.BitmapError || Error + /// bitmap.BitmapError.* - See bitmap.BitmapError + /// Error.VFSHandleNotSet - The handle has not previously been registered + /// + pub fn clearVFSHandle(self: *Self, handle: Handle) (bitmap.BitmapError || Error)!void { + if (try self.hasVFSHandle(handle)) { + try self.file_handles.clearEntry(handle); + _ = self.file_handle_mapping.remove(handle); + } else { + return Error.VFSHandleNotSet; + } + } }; /// @@ -381,3 +493,75 @@ test "create doesn't allocate kernel stack" { try std.testing.expectEqualSlices(usize, task.kernel_stack, &[_]usize{}); try std.testing.expectEqual(task.stack_pointer, 0); } + +test "addVFSHandle" { + var task = try Task.create(0, true, undefined, std.testing.allocator, false); + defer task.destroy(std.testing.allocator); + var node1 = vfs.Node{ .Dir = .{ .fs = undefined, .mount = null } }; + var node2 = vfs.Node{ .File = .{ .fs = undefined } }; + + const handle1 = (try task.addVFSHandle(&node1)) orelse return error.FailedToAddVFSHandle; + try expectEqual(handle1, 0); + try expectEqual(&node1, task.file_handle_mapping.get(handle1).?); + try expectEqual(true, try task.file_handles.isSet(handle1)); + + const handle2 = (try task.addVFSHandle(&node2)) orelse return error.FailedToAddVFSHandle; + try expectEqual(handle2, 1); + try expectEqual(&node2, task.file_handle_mapping.get(handle2).?); + try expectEqual(true, try task.file_handles.isSet(handle2)); +} + +test "hasFreeVFSHandle" { + var task = try Task.create(0, true, undefined, std.testing.allocator, false); + defer task.destroy(std.testing.allocator); + var node1 = vfs.Node{ .Dir = .{ .fs = undefined, .mount = null } }; + + try expect(task.hasFreeVFSHandle()); + + _ = (try task.addVFSHandle(&node1)) orelse return error.FailedToAddVFSHandle; + try expect(task.hasFreeVFSHandle()); + + var i: usize = 0; + const free_entries = task.file_handles.num_free_entries; + while (i < free_entries) : (i += 1) { + try expect(task.hasFreeVFSHandle()); + _ = task.file_handles.setFirstFree(); + } + try expect(!task.hasFreeVFSHandle()); +} + +test "getVFSHandle" { + var task = try Task.create(0, true, undefined, std.testing.allocator, false); + defer task.destroy(std.testing.allocator); + var node1 = vfs.Node{ .Dir = .{ .fs = undefined, .mount = null } }; + var node2 = vfs.Node{ .File = .{ .fs = undefined } }; + + const handle1 = (try task.addVFSHandle(&node1)) orelse return error.FailedToAddVFSHandle; + try expectEqual(&node1, (try task.getVFSHandle(handle1)).?); + + const handle2 = (try task.addVFSHandle(&node2)) orelse return error.FailedToAddVFSHandle; + try expectEqual(&node2, (try task.getVFSHandle(handle2)).?); + try expectEqual(&node1, (try task.getVFSHandle(handle1)).?); + + try expectEqual(task.getVFSHandle(handle2 + 1), null); +} + +test "clearVFSHandle" { + var task = try Task.create(0, true, undefined, std.testing.allocator, false); + defer task.destroy(std.testing.allocator); + var node1 = vfs.Node{ .Dir = .{ .fs = undefined, .mount = null } }; + var node2 = vfs.Node{ .File = .{ .fs = undefined } }; + + const handle1 = (try task.addVFSHandle(&node1)) orelse return error.FailedToAddVFSHandle; + const handle2 = (try task.addVFSHandle(&node2)) orelse return error.FailedToAddVFSHandle; + + try task.clearVFSHandle(handle1); + try expectEqual(false, try task.hasVFSHandle(handle1)); + + try task.clearVFSHandle(handle2); + try expectEqual(false, try task.hasVFSHandle(handle2)); + + try expectError(Task.Error.VFSHandleNotSet, task.clearVFSHandle(handle2 + 1)); + try expectError(Task.Error.VFSHandleNotSet, task.clearVFSHandle(handle2)); + try expectError(Task.Error.VFSHandleNotSet, task.clearVFSHandle(handle1)); +}