Unknown state [2025-08-04]

loader/.envrc

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+PATH_add zig-out/bin

loader/main.zig

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+const std = @import("std");
+
+const Hook = *const fn (i32, i32) callconv(.c) i32;
+
+pub fn main() !void {
+    std.log.debug("setting up watches...", .{});
+
+    var event: std.os.linux.inotify_event = undefined;
+    const event_buf = std.mem.asBytes(&event);
+
+    const fd: i32 = @intCast(std.os.linux.inotify_init1(std.os.linux.IN.NONBLOCK));
+    defer _ = std.os.linux.close(fd);
+
+    _ = std.os.linux.inotify_add_watch(fd, "./libroot.so", std.os.linux.IN.MODIFY);
+
+    std.log.debug("loading dylib...", .{});
+
+    var lib = try std.DynLib.open("./libroot.so");
+    defer lib.close();
+
+    var hook: Hook = lib.lookup(Hook, "hook").?;
+
+    var polls = [_]std.os.linux.pollfd{
+        .{ .fd = fd, .events = std.os.linux.POLL.IN, .revents = 0 },
+    };
+
+    while (true) {
+        const eps = std.os.linux.poll(&polls, polls.len, 0);
+        std.log.debug("eps: {d}", .{eps});
+        if (eps > 0) {
+            std.log.debug("event!", .{});
+            while (std.os.linux.read(fd, event_buf.ptr, event_buf.len) > 0) {
+                std.log.debug("consume.", .{});
+            }
+            std.log.debug("reloading.", .{});
+            lib.close();
+            lib = try std.DynLib.open("./libroot.so");
+            hook = lib.lookup(Hook, "hook").?;
+        }
+
+        std.log.debug("update", .{});
+        const res = hook(5, 7);
+        std.log.debug("hook(5, 7) = {d}", .{res});
+
+        std.time.sleep(std.time.ns_per_s);
+    }
+}

loader/root.zig

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+const std = @import("std");
+
+pub export fn hook(a: i32, b: i32) i32 {
+    return a * b;
+}
+

loader/sample.txt

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+content
+
+
+
+

loader/test.zig

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+const std = @import("std");
+comptime{
+@compileLog(std.math.maxInt(u64));
+}

loader/watch.zig

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+const std = @import("std");
+const linux = std.os.linux;
+
+pub fn main() !void {
+    std.log.debug("setting up watches.", .{});
+
+    var event: linux.inotify_event = undefined;
+    const event_buf = std.mem.asBytes(&event);
+
+    const fd: i32 = @intCast(linux.inotify_init1(linux.IN.NONBLOCK));
+    defer _ = linux.close(fd);
+
+    const wd: i32 = @intCast(linux.inotify_add_watch(
+        fd,
+        "sample.txt",
+        linux.IN.MODIFY | linux.IN.CLOSE_WRITE,
+    ));
+    defer _ = linux.inotify_rm_watch(fd, wd);
+
+    var fds = [_]linux.pollfd{
+        .{ .fd = fd, .events = linux.POLL.IN, .revents = 0 },
+    };
+
+    while (true) {
+        const k = linux.poll(&fds, fds.len, 1000);
+        std.log.debug("poll -> {d}", .{k});
+
+        if (k > 0) {
+            while (true) {
+                const n: isize = @bitCast(linux.read(
+                    fd,
+                    event_buf.ptr,
+                    event_buf.len,
+                ));
+                std.log.debug("read -> {d}", .{n});
+                std.time.sleep(500 * std.time.ns_per_ms);
+                if (n < 0) break;
+            }
+        }
+    }
+}