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getpwent/getgrent: advance iterator only on success

This commit is contained in:
Motiejus Jakštys 2022-07-21 11:23:13 +03:00
parent 2ceb3d5c29
commit 4bd44d10b7
3 changed files with 44 additions and 17 deletions

View File

@ -1,15 +1,16 @@
const std = @import("std");
const mem = std.mem;
const assert = std.debug.assert;
const Allocator = mem.Allocator;
const ArrayList = std.ArrayList;
const BufSet = std.BufSet;
const pad = @import("padding.zig");
const validate = @import("validate.zig");
const compress = @import("compress.zig");
const InvalidRecord = validate.InvalidRecord;
const mem = std.mem;
const Allocator = mem.Allocator;
const ArrayList = std.ArrayList;
const BufSet = std.BufSet;
const PackedGroup = @This();
pub const GroupStored = struct {
@ -65,18 +66,30 @@ fn validateUtf8(s: []const u8) InvalidRecord!void {
pub const Iterator = struct {
section: []const u8,
nextStart: usize = 0,
next_start: usize = 0,
idx: u32 = 0,
total: u32,
advance_by: usize = 0,
pub fn next(it: *Iterator) ?PackedGroup {
if (it.idx == it.total) return null;
const gr = it.peek() orelse return null;
it.advance();
return gr;
}
const entry = fromBytes(it.section[it.nextStart..]);
it.nextStart += entry.end;
it.idx += 1;
pub fn peek(it: *Iterator) ?PackedGroup {
if (it.idx == it.total) return null;
const entry = fromBytes(it.section[it.next_start..]);
it.advance_by = entry.end;
return entry.group;
}
pub fn advance(it: *Iterator) void {
assert(it.advance_by > 0);
it.idx += 1;
it.next_start += it.advance_by;
it.advance_by = 0;
}
};
pub fn iterator(section: []const u8, total: u32) Iterator {

View File

@ -105,19 +105,31 @@ pub fn fromBytes(bytes: []const u8) Entry {
pub const Iterator = struct {
section: []const u8,
nextStart: usize = 0,
next_start: usize = 0,
shell_reader: ShellReader,
idx: u32 = 0,
total: u32,
advance_by: usize = 0,
pub fn next(it: *Iterator) ?PackedUser {
if (it.idx == it.total) return null;
const u = it.peek() orelse return null;
it.advance();
return u;
}
const entry = PackedUser.fromBytes(it.section[it.nextStart..]);
it.nextStart += entry.end;
it.idx += 1;
pub fn peek(it: *Iterator) ?PackedUser {
if (it.idx == it.total) return null;
const entry = fromBytes(it.section[it.next_start..]);
it.advance_by = entry.end;
return entry.user;
}
pub fn advance(it: *Iterator) void {
assert(it.advance_by > 0);
it.idx += 1;
it.next_start += it.advance_by;
it.advance_by = 0;
}
};
pub fn iterator(section: []const u8, total: u32, shell_reader: ShellReader) Iterator {

View File

@ -370,7 +370,7 @@ fn getgrent_r(
defer state.getgrent_iterator_mu.unlock();
if (state.getgrent_iterator) |*it| {
const group = it.next() orelse {
const group = it.peek() orelse {
errnop.* = 0;
return c.NSS_STATUS_NOTFOUND;
};
@ -381,6 +381,7 @@ fn getgrent_r(
state.file.db.packCGroup(&group, buffer[0..buflen]);
if (cgroup1) |cgroup| {
it.advance();
result.* = cgroup;
return c.NSS_STATUS_SUCCESS;
} else |err| switch (err) {
@ -422,7 +423,7 @@ fn getpwent_r(
defer state.getpwent_iterator_mu.unlock();
if (state.getpwent_iterator) |*it| {
const user = it.next() orelse {
const user = it.peek() orelse {
errnop.* = 0;
return c.NSS_STATUS_NOTFOUND;
};
@ -435,6 +436,7 @@ fn getpwent_r(
},
};
it.advance();
result.* = cuser;
return c.NSS_STATUS_SUCCESS;
} else {