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bring back additional_gids_offset

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Motiejus Jakštys
2022-02-24 05:32:27 +02:00
committed by Motiejus Jakštys
parent c0afca00b0
commit 3bf1b3fc01
2 changed files with 39 additions and 30 deletions
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19
src/user.zig
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@@ -6,16 +6,17 @@ const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const cast = std.math.cast;
const PackedUserSize = @divExact(@bitSizeOf(PackedUser), 8);
pub const PackedUser = 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: u10,
padding: u3,
gecos_len: u8,
// blobLength returns the length of the blob storing string values.
pub fn blobLength(self: *const PackedUser) usize {
@@ -107,7 +108,7 @@ pub const UserWriter = struct {
const home_len = try downCast(u6, user.home.len - 1);
const name_len = try downCast(u5, user.name.len - 1);
const shell_len = try downCast(u6, user.shell.len - 1);
const gecos_len = try downCast(u10, user.gecos.len);
const gecos_len = try downCast(u8, user.gecos.len);
try validateUtf8(user.home);
try validateUtf8(user.name);
@@ -117,13 +118,13 @@ pub const UserWriter = struct {
var puser = PackedUser{
.uid = user.uid,
.gid = user.gid,
.additional_gids_offset = 1 << 29 - 1,
.shell_here = self.shellIndexFn(user.shell) == null,
.shell_len_or_idx = self.shellIndexFn(user.shell) orelse shell_len,
.home_len = home_len,
.name_is_a_suffix = std.mem.endsWith(u8, user.home, user.name),
.name_len = name_len,
.gecos_len = gecos_len,
.padding = 0,
};
try self.appendTo.appendSlice(std.mem.asBytes(&puser));
@@ -241,7 +242,13 @@ pub const UserReader = struct {
const testing = std.testing;
test "PackedUser internal and external alignment" {
try testing.expectEqual(@bitSizeOf(PackedUser), @sizeOf(PackedUser) * 8);
// External padding (PackedUserAlignmentBits) must be higher or equal to
// the "internal" PackedUser alignment. By aligning PackedUser we are also
// working around https://github.com/ziglang/zig/issues/10958 ; PackedUser
// cannot be converted from/to [@bitSizeOf(PackedUser)/8]u8;
// asBytes/bytesAsValue use @sizeOf, which is larger. Now we are putting no
// more than 1, but it probably could be higher.
try testing.expect(@bitSizeOf(PackedUser) - @sizeOf(PackedUser) * 8 <= 8);
}
fn testShellIndex(shell: []const u8) ?u6 {
@@ -284,7 +291,7 @@ test "construct PackedUser section" {
.uid = 0,
.gid = 4294967295,
.name = "n" ** 32,
.gecos = "g" ** 1023,
.gecos = "g" ** 255,
.home = "h" ** 64,
.shell = "s" ** 64,
} };