wip refactoring PackedUser
This commit is contained in:
parent
b924e3a935
commit
0f43f8b2d0
290
src/user.zig
290
src/user.zig
|
@ -4,50 +4,11 @@ const pad = @import("padding.zig");
|
||||||
const assert = std.debug.assert;
|
const assert = std.debug.assert;
|
||||||
const Allocator = std.mem.Allocator;
|
const Allocator = std.mem.Allocator;
|
||||||
const ArrayList = std.ArrayList;
|
const ArrayList = std.ArrayList;
|
||||||
const cast = std.math.cast;
|
const math = std.math;
|
||||||
|
const mem = std.mem;
|
||||||
|
|
||||||
const PackedUserSize = @divExact(@bitSizeOf(PackedUser), 8);
|
// TODO(motiejus) move to the struct where it's used.
|
||||||
pub const PackedUser = packed struct {
|
const shellIndexProto = fn (u6) []const u8;
|
||||||
uid: u32,
|
|
||||||
gid: u32,
|
|
||||||
additional_gids_offset: u29,
|
|
||||||
shell_here: bool,
|
|
||||||
shell_len_or_idx: u6,
|
|
||||||
home_len: u6,
|
|
||||||
name_is_a_suffix: bool,
|
|
||||||
name_len: u5,
|
|
||||||
gecos_len: u8,
|
|
||||||
|
|
||||||
// blobLength returns the length of the blob storing string values.
|
|
||||||
pub fn blobLength(self: *const PackedUser) usize {
|
|
||||||
var result: usize = self.realHomeLen();
|
|
||||||
if (!self.name_is_a_suffix) {
|
|
||||||
result += self.realNameLen();
|
|
||||||
}
|
|
||||||
result += self.realGecosLen();
|
|
||||||
if (self.shell_here) {
|
|
||||||
result += self.realShellLen();
|
|
||||||
}
|
|
||||||
|
|
||||||
return result;
|
|
||||||
}
|
|
||||||
|
|
||||||
pub fn realHomeLen(self: *const PackedUser) usize {
|
|
||||||
return @as(u32, self.home_len) + 1;
|
|
||||||
}
|
|
||||||
|
|
||||||
pub fn realNameLen(self: *const PackedUser) usize {
|
|
||||||
return @as(u32, self.name_len) + 1;
|
|
||||||
}
|
|
||||||
|
|
||||||
pub fn realShellLen(self: *const PackedUser) usize {
|
|
||||||
return @as(u32, self.shell_len_or_idx) + 1;
|
|
||||||
}
|
|
||||||
|
|
||||||
pub fn realGecosLen(self: *const PackedUser) usize {
|
|
||||||
return self.gecos_len;
|
|
||||||
}
|
|
||||||
};
|
|
||||||
const PackedUserAlignmentBits = 3;
|
const PackedUserAlignmentBits = 3;
|
||||||
|
|
||||||
pub const User = struct {
|
pub const User = struct {
|
||||||
|
@ -59,28 +20,94 @@ pub const User = struct {
|
||||||
shell: []const u8,
|
shell: []const u8,
|
||||||
};
|
};
|
||||||
|
|
||||||
// UserWriter accepts a naive User struct and returns a PackedUser
|
pub const PackedUser = struct {
|
||||||
pub const UserWriter = struct {
|
// TODO: use @bitSizeOf(Inner)/8:
|
||||||
// shellIndexFnType is a signature for a function that accepts a shell
|
//const InnerSize = @divExact(@bitSizeOf(Inner), 8);
|
||||||
// string and returns it's index in the global shell section. Passing a
|
|
||||||
// function makes tests easier, and removes the Shell dependency of this
|
|
||||||
// module.
|
|
||||||
const shellIndexFnType = fn ([]const u8) ?u6;
|
const shellIndexFnType = fn ([]const u8) ?u6;
|
||||||
|
|
||||||
appendTo: *ArrayList(u8),
|
const InnerSize = @sizeOf(Inner);
|
||||||
shellIndexFn: shellIndexFnType,
|
const Inner = packed struct {
|
||||||
|
uid: u32,
|
||||||
|
gid: u32,
|
||||||
|
additional_gids_offset: u29,
|
||||||
|
shell_here: bool,
|
||||||
|
shell_len_or_idx: u6,
|
||||||
|
home_len: u6,
|
||||||
|
name_is_a_suffix: bool,
|
||||||
|
name_len: u5,
|
||||||
|
gecos_len: u8,
|
||||||
|
|
||||||
pub fn init(
|
pub fn homeLen(self: *const PackedUser) usize {
|
||||||
appendTo: *ArrayList(u8),
|
return @as(u32, self.home_len) + 1;
|
||||||
shellIndexFn: shellIndexFnType,
|
}
|
||||||
) UserWriter {
|
|
||||||
return UserWriter{
|
pub fn nameLen(self: *const PackedUser) usize {
|
||||||
.appendTo = appendTo,
|
return @as(u32, self.name_len) + 1;
|
||||||
.shellIndexFn = shellIndexFn,
|
}
|
||||||
|
|
||||||
|
pub fn gecosLen(self: *const PackedUser) usize {
|
||||||
|
return self.gecos_len;
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn shellLen(self: *const PackedUser) usize {
|
||||||
|
return @as(u32, self.shell_len_or_idx) + 1;
|
||||||
|
}
|
||||||
|
|
||||||
|
// blobLength returns the length of the blob storing string values.
|
||||||
|
pub fn blobLength(self: *const Inner) usize {
|
||||||
|
var result: usize = self.homeLen();
|
||||||
|
if (!self.name_is_a_suffix) {
|
||||||
|
result += self.nameLen();
|
||||||
|
}
|
||||||
|
result += self.gecosLen();
|
||||||
|
if (self.shell_here) {
|
||||||
|
result += self.shellLen();
|
||||||
|
}
|
||||||
|
|
||||||
|
return result;
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn namePos(self: *const Inner) usize {
|
||||||
|
const name_len = self.nameLen();
|
||||||
|
if (self.name_is_a_suffix) {
|
||||||
|
return self.inner.homeLen() - name_len;
|
||||||
|
} else {
|
||||||
|
return self.homeLen();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn gecosPos(self: *const Inner) usize {
|
||||||
|
if (self.name_is_a_suffix) {
|
||||||
|
return self.homeLen();
|
||||||
|
} else {
|
||||||
|
return self.homeLen() + self.nameLen();
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn maybeShellPos(self: *const Inner) usize {
|
||||||
|
assert(self.shell_here);
|
||||||
|
return self.gecosPos() + self.gecosLen();
|
||||||
|
}
|
||||||
|
};
|
||||||
|
|
||||||
|
inner: Inner,
|
||||||
|
userdata: []const u8,
|
||||||
|
|
||||||
|
pub fn fromBytes(bytes: []const u8) PackedUser {
|
||||||
|
const inner = std.mem.bytesAsValue(
|
||||||
|
PackedUser,
|
||||||
|
bytes[0..@sizeOf(Inner)][0..@sizeOf(Inner)],
|
||||||
|
);
|
||||||
|
|
||||||
|
const startBlob = InnerSize;
|
||||||
|
const endBlob = startBlob + inner.blobLength();
|
||||||
|
return PackedUser{
|
||||||
|
.inner = inner,
|
||||||
|
.userdata = bytes[startBlob..endBlob],
|
||||||
};
|
};
|
||||||
}
|
}
|
||||||
|
|
||||||
pub fn downCast(comptime T: type, n: u64) error{InvalidRecord}!T {
|
fn downCast(comptime T: type, n: u64) error{InvalidRecord}!T {
|
||||||
return std.math.cast(T, n) catch |err| switch (err) {
|
return std.math.cast(T, n) catch |err| switch (err) {
|
||||||
error.Overflow => {
|
error.Overflow => {
|
||||||
return error.InvalidRecord;
|
return error.InvalidRecord;
|
||||||
|
@ -88,23 +115,19 @@ pub const UserWriter = struct {
|
||||||
};
|
};
|
||||||
}
|
}
|
||||||
|
|
||||||
pub fn validateUtf8(s: []const u8) error{InvalidRecord}!void {
|
fn validateUtf8(s: []const u8) error{InvalidRecord}!void {
|
||||||
if (!std.unicode.utf8ValidateSlice(s)) {
|
if (!std.unicode.utf8ValidateSlice(s)) {
|
||||||
return error.InvalidRecord;
|
return error.InvalidRecord;
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
// FIXME(motiejus) record valiation should return a separate type. For User
|
// packTo packs the User record and copies it to the given byte slice. The
|
||||||
// case, it should be length-bound slices and utf8-codepoints instead of
|
// slice must have at least maxRecordSize() bytes available.
|
||||||
// strings.
|
pub fn packTo(buf1: *[]u8, user: User, shellIndexFn: shellIndexFnType) error{InvalidRecord}!void {
|
||||||
//
|
std.debug.print("\nbuf1.len: {d}\n", .{buf1.*.len});
|
||||||
// zig does not have error contexts
|
var buf = buf1.*;
|
||||||
// (https://github.com/ziglang/zig/issues/2647) and length-limited slices.
|
const bufStart = @ptrToInt(&buf[0]);
|
||||||
// (It does have bounded_array, but that preallocates the maximum length,
|
|
||||||
// which is not great for User records). So I am using those excuses to
|
|
||||||
// do the validation here. I may move it once I learn the language better.
|
|
||||||
const appendUserErr = error{InvalidRecord} || Allocator.Error;
|
|
||||||
pub fn appendUser(self: *UserWriter, user: User) appendUserErr!void {
|
|
||||||
const home_len = try downCast(u6, user.home.len - 1);
|
const home_len = try downCast(u6, user.home.len - 1);
|
||||||
const name_len = try downCast(u5, user.name.len - 1);
|
const name_len = try downCast(u5, user.name.len - 1);
|
||||||
const shell_len = try downCast(u6, user.shell.len - 1);
|
const shell_len = try downCast(u6, user.shell.len - 1);
|
||||||
|
@ -115,39 +138,79 @@ pub const UserWriter = struct {
|
||||||
try validateUtf8(user.shell);
|
try validateUtf8(user.shell);
|
||||||
try validateUtf8(user.gecos);
|
try validateUtf8(user.gecos);
|
||||||
|
|
||||||
var puser = PackedUser{
|
const inner = Inner{
|
||||||
.uid = user.uid,
|
.uid = user.uid,
|
||||||
.gid = user.gid,
|
.gid = user.gid,
|
||||||
.additional_gids_offset = 1 << 29 - 1,
|
.additional_gids_offset = std.math.maxInt(u29),
|
||||||
.shell_here = self.shellIndexFn(user.shell) == null,
|
.shell_here = shellIndexFn(user.shell) == null,
|
||||||
.shell_len_or_idx = self.shellIndexFn(user.shell) orelse shell_len,
|
.shell_len_or_idx = shellIndexFn(user.shell) orelse shell_len,
|
||||||
.home_len = home_len,
|
.home_len = home_len,
|
||||||
.name_is_a_suffix = std.mem.endsWith(u8, user.home, user.name),
|
.name_is_a_suffix = std.mem.endsWith(u8, user.home, user.name),
|
||||||
.name_len = name_len,
|
.name_len = name_len,
|
||||||
.gecos_len = gecos_len,
|
.gecos_len = gecos_len,
|
||||||
};
|
};
|
||||||
|
const innerBytes = mem.asBytes(&inner);
|
||||||
|
|
||||||
try self.appendTo.appendSlice(std.mem.asBytes(&puser));
|
mem.copy(u8, buf, innerBytes);
|
||||||
try self.appendTo.appendSlice(user.home);
|
buf = buf[innerBytes.len..];
|
||||||
if (!puser.name_is_a_suffix) {
|
mem.copy(u8, buf, user.home);
|
||||||
try self.appendTo.appendSlice(user.name);
|
buf = buf[user.home.len..];
|
||||||
|
|
||||||
|
if (!inner.name_is_a_suffix) {
|
||||||
|
mem.copy(u8, buf, user.name);
|
||||||
|
buf = buf[user.name.len..];
|
||||||
}
|
}
|
||||||
try self.appendTo.appendSlice(user.gecos);
|
mem.copy(u8, buf, user.gecos);
|
||||||
if (puser.shell_here) {
|
buf = buf[user.gecos.len..];
|
||||||
try self.appendTo.appendSlice(user.shell);
|
if (inner.shell_here) {
|
||||||
|
mem.copy(u8, buf, user.shell);
|
||||||
|
buf = buf[user.shell.len..];
|
||||||
}
|
}
|
||||||
|
|
||||||
try self.appendTo.appendNTimes(0, pad.roundUpPadding(
|
_ = bufStart;
|
||||||
u64,
|
//const bufLen = @ptrToInt(&buf[0]) - bufStart;
|
||||||
PackedUserAlignmentBits,
|
//const padding = pad.roundUpPadding(u64, PackedUserAlignmentBits, bufLen);
|
||||||
self.appendTo.items.len,
|
//mem.set(u8, buf[0..padding], 0);
|
||||||
));
|
}
|
||||||
|
|
||||||
|
// maxSize is the maximum number of records a PackedUser can take
|
||||||
|
// (struct + userdata).
|
||||||
|
pub fn maxSize() usize {
|
||||||
|
const unpadded = InnerSize +
|
||||||
|
std.math.maxInt(u6) + // home
|
||||||
|
std.math.maxInt(u5) + // name
|
||||||
|
std.math.maxInt(u6) + // shell
|
||||||
|
std.math.maxInt(u8); // gecos
|
||||||
|
return pad.roundUp(u64, PackedUserAlignmentBits, unpadded);
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn home(self: *const PackedUser) []const u8 {
|
||||||
|
return self.userdata[0..self.inner.homeLen()];
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn name(self: *const PackedUser) []const u8 {
|
||||||
|
const name_pos = self.inner.namePos();
|
||||||
|
const name_len = self.inner.nameLen();
|
||||||
|
return self.userdata[name_pos .. name_pos + name_len];
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn gecos(self: *const PackedUser) []const u8 {
|
||||||
|
const gecos_pos = self.inner.gecosPos();
|
||||||
|
const gecos_len = self.inner.gecosLen();
|
||||||
|
return self.userdata[gecos_pos .. gecos_pos + gecos_len];
|
||||||
|
}
|
||||||
|
|
||||||
|
pub fn shell(self: *const PackedUser, shellIndex: shellIndexProto) []const u8 {
|
||||||
|
if (self.inner.shell_here) {
|
||||||
|
const shell_pos = self.inner.maybeShellPos();
|
||||||
|
const shell_len = self.inner.shellLen();
|
||||||
|
return self.userdata[shell_pos .. shell_pos + shell_len];
|
||||||
|
}
|
||||||
|
return shellIndex(self.inner.shell_len_or_idx);
|
||||||
}
|
}
|
||||||
};
|
};
|
||||||
|
|
||||||
pub const UserReader = struct {
|
pub const UserReader = struct {
|
||||||
const shellIndexProto = fn (u6) []const u8;
|
|
||||||
|
|
||||||
section: []const u8,
|
section: []const u8,
|
||||||
shellIndex: shellIndexProto,
|
shellIndex: shellIndexProto,
|
||||||
|
|
||||||
|
@ -182,25 +245,25 @@ pub const UserReader = struct {
|
||||||
const endBlob = startBlob + u.blobLength();
|
const endBlob = startBlob + u.blobLength();
|
||||||
const section = self.section[startBlob..endBlob];
|
const section = self.section[startBlob..endBlob];
|
||||||
|
|
||||||
const home = section[0..u.realHomeLen()];
|
const home = section[0..u.homeLen()];
|
||||||
var name: []const u8 = undefined;
|
var name: []const u8 = undefined;
|
||||||
var pos: usize = undefined;
|
var pos: usize = undefined;
|
||||||
|
|
||||||
if (u.name_is_a_suffix) {
|
if (u.name_is_a_suffix) {
|
||||||
const name_start = u.realHomeLen() - u.realNameLen();
|
const name_start = u.homeLen() - u.nameLen();
|
||||||
name = section[name_start..u.realHomeLen()];
|
name = section[name_start..u.homeLen()];
|
||||||
pos = u.realHomeLen();
|
pos = u.homeLen();
|
||||||
} else {
|
} else {
|
||||||
const name_start = u.realHomeLen();
|
const name_start = u.homeLen();
|
||||||
name = section[name_start .. name_start + u.realNameLen()];
|
name = section[name_start .. name_start + u.nameLen()];
|
||||||
pos = name_start + u.realNameLen();
|
pos = name_start + u.nameLen();
|
||||||
}
|
}
|
||||||
const gecos = section[pos .. pos + u.realGecosLen()];
|
const gecos = section[pos .. pos + u.gecosLen()];
|
||||||
pos += u.realGecosLen();
|
pos += u.gecosLen();
|
||||||
|
|
||||||
var shell: []const u8 = undefined;
|
var shell: []const u8 = undefined;
|
||||||
if (u.shell_here) {
|
if (u.shell_here) {
|
||||||
shell = section[pos .. pos + u.realShellLen()];
|
shell = section[pos .. pos + u.shellLen()];
|
||||||
} else {
|
} else {
|
||||||
shell = self.shellIndex(u.shell_len_or_idx);
|
shell = self.shellIndex(u.shell_len_or_idx);
|
||||||
}
|
}
|
||||||
|
@ -272,7 +335,6 @@ test "construct PackedUser section" {
|
||||||
var buf = ArrayList(u8).init(testing.allocator);
|
var buf = ArrayList(u8).init(testing.allocator);
|
||||||
defer buf.deinit();
|
defer buf.deinit();
|
||||||
|
|
||||||
var writer = UserWriter.init(&buf, testShellIndex);
|
|
||||||
const users = [_]User{ User{
|
const users = [_]User{ User{
|
||||||
.uid = 1000,
|
.uid = 1000,
|
||||||
.gid = 1000,
|
.gid = 1000,
|
||||||
|
@ -296,19 +358,23 @@ test "construct PackedUser section" {
|
||||||
.shell = "s" ** 64,
|
.shell = "s" ** 64,
|
||||||
} };
|
} };
|
||||||
for (users) |user| {
|
for (users) |user| {
|
||||||
try writer.appendUser(user);
|
std.debug.print("\nmaxSize: {d}\n", .{PackedUser.maxSize()});
|
||||||
|
try buf.ensureUnusedCapacity(PackedUser.maxSize());
|
||||||
|
buf.items[0] = 1;
|
||||||
|
std.debug.print("\nbuf.items.len: {d}\n", .{buf.items.len});
|
||||||
|
try PackedUser.packTo(&buf.items, user, testShellIndex);
|
||||||
}
|
}
|
||||||
|
|
||||||
var rd = UserReader.init(buf.items, testShell);
|
//var rd = UserReader.init(buf.items, testShell);
|
||||||
|
|
||||||
var it = rd.iterator();
|
//var it = rd.iterator();
|
||||||
var i: u32 = 0;
|
//var i: u32 = 0;
|
||||||
while (it.next()) |user| : (i += 1) {
|
//while (it.next()) |user| : (i += 1) {
|
||||||
try testing.expectEqual(users[i].uid, user.uid);
|
// try testing.expectEqual(users[i].uid, user.uid);
|
||||||
try testing.expectEqual(users[i].gid, user.gid);
|
// try testing.expectEqual(users[i].gid, user.gid);
|
||||||
try testing.expectEqualStrings(users[i].name, user.name);
|
// try testing.expectEqualStrings(users[i].name, user.name);
|
||||||
try testing.expectEqualStrings(users[i].gecos, user.gecos);
|
// try testing.expectEqualStrings(users[i].gecos, user.gecos);
|
||||||
try testing.expectEqualStrings(users[i].home, user.home);
|
// try testing.expectEqualStrings(users[i].home, user.home);
|
||||||
try testing.expectEqualStrings(users[i].shell, user.shell);
|
// try testing.expectEqualStrings(users[i].shell, user.shell);
|
||||||
}
|
//}
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in New Issue