From c5489bbefb070eeb3a49b80c534bd605b8fabc4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@jakstys.lt>
Date: Fri, 11 Oct 2024 08:37:13 +0200
Subject: [PATCH] pointer chasing

---
 build.zig      |  1 -
 src/tunnel.zig | 18 +++++++++++++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/build.zig b/build.zig
index 5720db2..8df2ed5 100644
--- a/build.zig
+++ b/build.zig
@@ -70,7 +70,6 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
     });
 
-    exe_unit_tests.setExecCmd(&.{"/run/current-system/sw/bin/false"});
     const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
 
     // Similar to creating the run step earlier, this exposes a `test` step to
diff --git a/src/tunnel.zig b/src/tunnel.zig
index 91260ab..ca09842 100644
--- a/src/tunnel.zig
+++ b/src/tunnel.zig
@@ -9,7 +9,8 @@ const IFF_TUN = 0x0001; // <linux/if_tun.h>
 const IFF_NO_PI = 0x1000; // <linux/if_tun.h>
 const TUNSETIFF = 0x400454ca; // compile a C program, run and see
 
-dev: [posix.IFNAMESIZE - 1:0]u8,
+dev_buf: [posix.IFNAMESIZE:0]u8,
+dev: [:0]u8,
 tunFile: posix.fd_t,
 
 pub fn init(devname: ?[]const u8) !Tunnel {
@@ -29,9 +30,7 @@ pub fn init(devname: ?[]const u8) !Tunnel {
     ifr.ifru.flags = IFF_TUN | IFF_NO_PI;
 
     if (devname) |name| {
-        if (name.len >= posix.IFNAMESIZE - 1) {
-            return error.BadInterfaceName;
-        }
+        if (name.len >= posix.IFNAMESIZE - 1) return error.BadInterfaceName;
         @memcpy(ifr.ifrn.name[0..name.len], name);
     }
 
@@ -43,9 +42,15 @@ pub fn init(devname: ?[]const u8) !Tunnel {
 
     var tunnel = Tunnel{
         .dev = undefined,
+        .dev_buf = .{0} ** posix.IFNAMESIZE,
         .tunFile = tunFile,
     };
-    @memcpy(tunnel.dev[0..posix.IFNAMESIZE], mem.sliceTo(&ifr.ifrn.name, 0));
+
+    const ifname = mem.sliceTo(&ifr.ifrn.name, 0);
+    @memcpy(tunnel.dev_buf[0..ifname.len], ifname);
+    tunnel.dev = tunnel.dev_buf[0..ifname.len :0];
+    std.debug.print("&tunnel = {*}\n", .{&tunnel});
+    std.debug.print("&tunnel.dev = {*}\n", .{tunnel.dev});
 
     return tunnel;
 }
@@ -58,5 +63,8 @@ const Tunnel = @This();
 
 test "init" {
     var tun = try init("nyotun");
+    std.debug.print("&tun = {*}\n", .{&tun});
+    std.debug.print("&tun.dev = {*}\n", .{tun.dev});
+    try std.testing.expectEqualStrings("nyotun", tun.dev);
     tun.close();
 }