Add dual version handling, relative path handling

src/hosts.zig

@@ -61,16 +61,7 @@ fn purge_existing(old_hosts: std.fs.File, tmp_hosts: std.fs.File) !void {
     }
 }
 
-fn append_new(tmp_hosts: std.fs.File, addr: std.net.Address, local_domain: util.Domain) !void {
+fn write_subdomains_map(writer: std.fs.File.Writer, addr: std.net.Address, local_domain: util.Domain) !void {
-    const writer = tmp_hosts.writer();
-    var buff = [_]u8{0x00} ** FILE_LINE_BUFF_SIZE;
-
-    // write output
-    const header_len = hosts_header.*.len;
-    @memcpy(buff[0..header_len], hosts_header);
-    try writer.writeAll(buff[0..header_len]);
-    try writer.writeByte('\n');
-
     var subdomains = try get_subdomains();
     const domain = try util.getenv("TARGET_DOMAIN");
 
@@ -86,6 +77,24 @@ fn append_new(tmp_hosts: std.fs.File, addr: std.net.Address, local_domain: util.
         try std.fmt.format(writer, "{s} {s}.{s}\n", .{ addr_str, subdomain, domain });
     }
     try std.fmt.format(writer, "{s} {s}\n", .{ addr_str, local_domain.name });
+}
+
+fn append_new(tmp_hosts: std.fs.File, ip: util.IP, local_domain: util.Domain) !void {
+    const writer = tmp_hosts.writer();
+    var buff = [_]u8{0x00} ** FILE_LINE_BUFF_SIZE;
+
+    // write output
+    const header_len = hosts_header.*.len;
+    @memcpy(buff[0..header_len], hosts_header);
+    try writer.writeAll(buff[0..header_len]);
+    try writer.writeByte('\n');
+
+    if (ip.v6) |addr| {
+        try write_subdomains_map(writer, addr, local_domain);
+    }
+    if (ip.v4) |addr| {
+        try write_subdomains_map(writer, addr, local_domain);
+    }
 
     // add extra final newline
     try writer.writeByte('\n');
@@ -97,22 +106,20 @@ fn get_subdomains() !std.mem.SplitIterator(u8, .scalar) {
 }
 
 fn create_tmp_hosts(ip: util.IP, domain: util.Domain) !void {
-    var old_hosts = try std.fs.openFileAbsoluteZ(try util.getenv("OLD_HOSTS_PATH"), .{ .mode = .read_only });
+    var old_hosts = try std.fs.Dir.openFileZ(util.cwd, try util.getenv("OLD_HOSTS_PATH"), .{ .mode = .read_only });
     defer old_hosts.close();
-    var tmp_hosts = try std.fs.createFileAbsoluteZ(try util.getenv("TMP_HOSTS_PATH"), .{ .truncate = true });
+    var tmp_hosts = try std.fs.Dir.createFileZ(util.cwd, try util.getenv("TMP_HOSTS_PATH"), .{ .truncate = true });
     defer tmp_hosts.close();
 
     try purge_existing(old_hosts, tmp_hosts);
-    if (ip) |addr| {
+    try append_new(tmp_hosts, ip, domain);
-        try append_new(tmp_hosts, addr, domain);
-    }
 }
 
 fn move_tmp_hosts() !void {
-    var target_hosts = try std.fs.createFileAbsoluteZ(try util.getenv("OLD_HOSTS_PATH"), .{ .lock = .exclusive });
+    var target_hosts = try std.fs.Dir.createFileZ(util.cwd, try util.getenv("OLD_HOSTS_PATH"), .{ .lock = .exclusive });
     defer target_hosts.close();
     const target_writer = target_hosts.writer();
-    var tmp_hosts = try std.fs.openFileAbsoluteZ(try util.getenv("TMP_HOSTS_PATH"), .{});
+    var tmp_hosts = try std.fs.Dir.openFileZ(util.cwd, try util.getenv("TMP_HOSTS_PATH"), .{});
     defer tmp_hosts.close();
     const source_reader = tmp_hosts.reader();
 
@@ -122,5 +129,5 @@ fn move_tmp_hosts() !void {
         }
     };
 
-    try std.fs.deleteFileAbsoluteZ(try util.getenv("TMP_HOSTS_PATH"));
+    try std.fs.Dir.deleteFileZ(util.cwd, try util.getenv("TMP_HOSTS_PATH"));
 }

src/mdns.zig

@@ -2,7 +2,6 @@ const std = @import("std");
 const util = @import("util.zig");
 
 const MDNSError = error{
-    Unimplemented,
     SocketInitFail,
     UDPConnectFail,
     UDPSendFail,
@@ -14,10 +13,22 @@ const MDNSError = error{
 };
 
 pub fn get_mdns(domain: util.Domain, ip_info: util.IPInfo) !util.IP {
+    if (ip_info.version != .Both) {
         const sock = try send_query(domain, ip_info);
         return receive_response(sock, ip_info);
     }
 
+    const ip_info4 = util.IPInfo{ .version = .IPv4, .interface = ip_info.interface };
+    var sock = try send_query(domain, ip_info4);
+    const addr_v4 = try receive_response(sock, ip_info4);
+
+    const ip_info6 = util.IPInfo{ .version = .IPv4, .interface = ip_info.interface };
+    sock = try send_query(domain, ip_info6);
+    const addr_v6 = try receive_response(sock, ip_info6);
+
+    return util.merge_addrs(addr_v4, addr_v6);
+}
+
 const socket = c_int;
 const MSG_BUFF_SIZE = 200;
 
@@ -25,6 +36,7 @@ fn get_mdns_socket(ip_info: util.IPInfo) !socket {
     const sock = std.c.socket(switch (ip_info.version) {
         util.IP_VER_ENUM.IPv4 => std.c.AF.INET,
         util.IP_VER_ENUM.IPv6 => std.c.AF.INET6,
+        else => unreachable,
     }, std.c.SOCK.DGRAM, std.c.IPPROTO.UDP);
     if (sock == -1) {
         return MDNSError.SocketInitFail;
@@ -59,6 +71,7 @@ fn construct_mdns_query(domain: util.Domain, ip_info: util.IPInfo, buff: []u8) !
         [_]u8{ 0x00, switch (ip_info.version) {
         util.IP_VER_ENUM.IPv4 => 0x01,
         util.IP_VER_ENUM.IPv6 => 0x1c,
+        else => unreachable,
     } } ++ // A or AAAA record
         [_]u8{ 0x00, 0x01 } // IN query
     ;
@@ -77,6 +90,7 @@ fn get_target_address(ip_info: util.IPInfo) !std.net.Address {
             try std.fmt.format(writer, "ff02::fb%{s}", .{ip_info.interface.?});
             break :blk buf[0..writer.context.pos];
         },
+        else => unreachable,
     };
     return std.net.Address.resolveIp(target_addr, 5353);
 }
@@ -153,6 +167,7 @@ fn parse_mdns_response(response: []u8, ip_info: util.IPInfo) !util.IP {
         if (switch (ip_info.version) {
             util.IP_VER_ENUM.IPv4 => ip_len != 4,
             util.IP_VER_ENUM.IPv6 => ip_len != 16,
+            else => unreachable,
         }) {
             continue;
         }
@@ -170,5 +185,12 @@ fn parse_mdns_response(response: []u8, ip_info: util.IPInfo) !util.IP {
             }
         }
     }
-    return addr;
+    if (addr == null) {
+        return MDNSError.NoMatchingAddress;
+    }
+    return switch (ip_info.version) {
+        .IPv4 => util.IP{ .v4 = addr },
+        .IPv6 => util.IP{ .v6 = addr },
+        else => unreachable,
+    };
 }

src/util.zig

@@ -7,14 +7,26 @@ const ArgError = error{
     InterfaceRequired,
     InvalidInterface,
     EnvVarNotSet,
+    InvalidOldHostsPath,
 };
 
 pub const IP_VER_ENUM = enum(u3) {
+    Both = 0,
     IPv4 = 4,
     IPv6 = 6,
 };
 
-pub const IP = ?std.net.Address;
+pub const IP = struct {
+    v4: ?std.net.Address = null,
+    v6: ?std.net.Address = null,
+};
+
+pub fn merge_addrs(v4: IP, v6: IP) IP {
+    return IP{
+        .v4 = v4.v4,
+        .v6 = v6.v6,
+    };
+}
 
 pub const IPInfo = struct {
     version: IP_VER_ENUM,
@@ -31,10 +43,12 @@ pub fn getenv(key: [*:0]const u8) ![*:0]const u8 {
 }
 
 pub fn check_perms() !void {
-    var f = try std.fs.openFileAbsoluteZ(try getenv("OLD_HOSTS_PATH"), .{ .mode = .write_only });
+    var f = try std.fs.Dir.openFileZ(cwd, try getenv("OLD_HOSTS_PATH"), .{ .mode = .write_only });
     f.close();
 }
 
+pub const cwd = std.fs.cwd();
+
 pub fn get_input() !struct {
     Domain,
     IPInfo,
@@ -49,7 +63,7 @@ pub fn get_input() !struct {
     const ip_ver = std.meta.intToEnum(IP_VER_ENUM, std.fmt.parseInt(u3, ip_ver_str, 10) catch return ArgError.InvalidAddressVer) catch return ArgError.InvalidAddressVer;
 
     var iface: ?[:0]const u8 = null;
-    if (ip_ver == IP_VER_ENUM.IPv6) {
+    if (ip_ver != IP_VER_ENUM.IPv4) {
         iface = args.next() orelse return ArgError.InterfaceRequired;
         if (std.c.if_nametoindex(iface.?) == 0) {
             return ArgError.InvalidInterface;