Config: perform basic validation

This just makes sure the parking posture is within the valid range of
motion of the rotator.

build.zig

@@ -22,6 +22,12 @@ pub fn build(b: *std.Build) void {
         .{ .target = target, .optimize = optimize, .use_udev = use_udev },
     );
     exe.linkLibrary(ljacklm_dep.artifact("ljacklm"));
+    exe.root_module.addImport(
+        "udev_rules",
+        b.addModule("udev_rules", .{
+            .root_source_file = b.path("deps/labjack/exodriver/udev_rules.zig"),
+        }),
+    );
 
     b.installArtifact(exe);
 }

deps/labjack/exodriver/udev_rules.zig

@@ -0,0 +1,2 @@
+pub const rules_filename = "90-labjack.rules";
+pub const rules = @embedFile(rules_filename);

src/Config.zig

@@ -8,7 +8,7 @@ const Config = @This();
 var global_internal: Config = undefined;
 pub const global: *const Config = &global_internal;
 
-pub fn load(allocator: std.mem.Allocator, reader: anytype) !void {
+pub fn load(allocator: std.mem.Allocator, reader: anytype, err_writer: anytype) !void {
     var jread = std.json.Reader(1024, @TypeOf(reader)).init(allocator, reader);
     defer jread.deinit();
 
@@ -18,6 +18,8 @@ pub fn load(allocator: std.mem.Allocator, reader: anytype) !void {
         &jread,
         .{},
     );
+
+    try global_internal.validate(err_writer);
 }
 
 pub fn loadDefault(allocator: std.mem.Allocator) void {
@@ -30,6 +32,57 @@ pub fn destroy(allocator: std.mem.Allocator) void {
     _ = allocator;
 }
 
+pub fn validate(self: Config, err_writer: anytype) !void {
+    var valid: bool = true;
+
+    // zig fmt: off
+    if (
+        self.controller.parking_posture.azimuth < (
+            self.labjack.feedback_calibration.azimuth.minimum.angle
+            + self.controller.angle_offset.azimuth
+        ) or self.controller.parking_posture.azimuth > (
+            self.labjack.feedback_calibration.azimuth.maximum.angle
+            + self.controller.angle_offset.azimuth
+        )
+    ) {
+        // zig fmt: on
+        valid = false;
+        try err_writer.print(
+            "Config validation failed: Parking azimuth {d:.1} is outside of the valid azimuth range {d:.1} - {d:.1}\n",
+            .{
+                self.controller.parking_posture.azimuth,
+                self.labjack.feedback_calibration.azimuth.minimum.angle + self.controller.angle_offset.azimuth,
+                self.labjack.feedback_calibration.azimuth.maximum.angle + self.controller.angle_offset.azimuth,
+            },
+        );
+    }
+
+    // zig fmt: off
+    if (
+        self.controller.parking_posture.elevation < (
+            self.labjack.feedback_calibration.elevation.minimum.angle
+            + self.controller.angle_offset.elevation
+        ) or self.controller.parking_posture.elevation > (
+            self.labjack.feedback_calibration.elevation.maximum.angle
+            + self.controller.angle_offset.elevation
+        )
+    ) {
+        // zig fmt: on
+        valid = false;
+        try err_writer.print(
+            "Config validation failed: Parking elevation {d:.1} is outside of the valid elevation range {d:.1} - {d:.1}\n",
+            .{
+                self.controller.parking_posture.elevation,
+                self.labjack.feedback_calibration.elevation.minimum.angle + self.controller.angle_offset.elevation,
+                self.labjack.feedback_calibration.elevation.maximum.angle + self.controller.angle_offset.elevation,
+            },
+        );
+    }
+
+    if (!valid)
+        return error.InvalidConfig;
+}
+
 rotctl: RotControlConfig = .{
     .listen_address = "127.0.0.1",
     .listen_port = 4533,

src/LabjackYaesu.zig

@@ -35,18 +35,44 @@ pub fn init(allocator: std.mem.Allocator) !LabjackYaesu {
     };
 }
 
-pub fn setTarget(self: LabjackYaesu, target: AzEl) void {
+fn inRange(request: f64, comptime dof: enum { azimuth, elevation }) bool {
+    return switch (dof) {
+        // zig fmt: off
+        .azimuth => request >= (
+                  config.labjack.feedback_calibration.azimuth.minimum.angle
+                + config.controller.angle_offset.azimuth
+            ) and request <= (
+                  config.labjack.feedback_calibration.azimuth.maximum.angle
+                + config.controller.angle_offset.azimuth
+        ),
+        .elevation => request >= (
+                  config.labjack.feedback_calibration.elevation.minimum.angle
+                + config.controller.angle_offset.elevation
+            ) and request <= (
+                  config.labjack.feedback_calibration.elevation.maximum.angle
+                + config.controller.angle_offset.elevation
+        ),
+        // zig fmt: on
+    };
+}
+
+pub fn setTarget(self: LabjackYaesu, target: AzEl) error{OutOfRange}!void {
     self.lock.lock();
     defer self.lock.unlock();
 
-    const controller = @constCast(self.controller);
-    controller.target = .{
+    const masked_target: AzEl = .{
         .azimuth = target.azimuth,
         .elevation = @min(
             @max(target.elevation, config.controller.elevation_mask),
             180.0 - config.controller.elevation_mask,
         ),
     };
+
+    if (!inRange(masked_target.azimuth, .azimuth) or !inRange(masked_target.elevation, .elevation))
+        return error.OutOfRange;
+
+    const controller = @constCast(self.controller);
+    controller.target = masked_target;
     controller.requested_state = .running;
 }
 
@@ -87,7 +113,7 @@ pub fn stop(self: LabjackYaesu) void {
 }
 
 pub fn startPark(self: LabjackYaesu) void {
-    self.setTarget(config.controller.parking_posture);
+    self.setTarget(config.controller.parking_posture) catch unreachable;
 }
 
 fn runController(controller: *Controller) void {

src/RotCtl.zig

@@ -142,19 +142,19 @@ fn setPosition(self: *RotCtl, _: []const u8, tokens: *TokenIter) CommandError!vo
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
     };
 
-    if (!inRange(azimuth, .azimuth))
-        return self.replyStatus(.invalid_parameter) catch error.BadOutput;
-
     const elevation = std.fmt.parseFloat(f64, tokens.next() orelse {
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
     }) catch {
         return self.replyStatus(.invalid_parameter) catch error.BadOutput;
     };
 
-    if (!inRange(elevation, .elevation))
-        return self.replyStatus(.invalid_parameter) catch error.BadOutput;
+    self.rotator.setTarget(.{
+        .azimuth = azimuth,
+        .elevation = elevation,
+    }) catch |err| switch (err) {
+        error.OutOfRange => return self.replyStatus(.invalid_parameter) catch error.BadOutput,
+    };
 
-    self.rotator.setTarget(.{ .azimuth = azimuth, .elevation = elevation });
     return self.replyStatus(.okay) catch error.BadOutput;
 }
 

src/main.zig

@@ -4,35 +4,157 @@ const Config = @import("./Config.zig");
 const lj = @import("./labjack.zig");
 const RotCtl = @import("./RotCtl.zig");
 
+const udev = @import("udev_rules");
+
 const log = std.log.scoped(.main);
 
+fn printStderr(comptime fmt: []const u8, args: anytype) void {
+    std.debug.print(fmt ++ "\n", args);
+}
+
+const commands = .{
+    .install_udev = "install-udev-rules",
+    .write_config = "write-default-config",
+    .run = "run",
+};
+
+const command_help = .{
+    .install_udev = "[udev rules.d path]: Install the built-in LabJack u12 udev rules file. May require sudo privileges. Linux only.",
+    .write_config = "[path]: write the default configuration to a json file.",
+    .run = "[config path]: run the rotctl interface with the provided config.",
+};
+
 pub fn main() !u8 {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();
     const allocator = gpa.allocator();
 
-    blk: {
-        const conf_file = std.fs.cwd().openFile("yaes.json", .{}) catch {
-            log.warn("Could not load config file yaes.json. Using default config.", .{});
-            Config.loadDefault(allocator);
-            break :blk;
-        };
-        defer conf_file.close();
+    const args = std.process.argsAlloc(allocator) catch {
+        printStderr("Couldn't allocate arguments array", .{});
+        return 1;
+    };
+    defer std.process.argsFree(allocator, args);
 
-        Config.load(allocator, conf_file.reader()) catch {
-            log.err("Could not parse config file yaes.json. Good luck figuring out why.", .{});
+    if (args.len < 2) {
+        printHelp();
+        return 1;
+    }
+
+    if (std.mem.eql(u8, args[1], commands.install_udev)) {
+        if (args.len > 3) {
+            printHelp();
+            return 1;
+        }
+
+        return installUdevRules(if (args.len == 3) args[2] else null);
+    } else if (std.mem.eql(u8, args[1], commands.write_config)) {
+        if (args.len > 3) {
+            printHelp();
+            return 1;
+        }
+
+        Config.loadDefault(allocator);
+        return writeDefaultConfig(if (args.len == 3) args[2] else null);
+    } else if (std.mem.eql(u8, args[1], commands.run)) {
+        if (args.len > 3) {
+            printHelp();
+            return 1;
+        }
+        blk: {
+            const confpath = if (args.len == 3) args[2] else "yaes.json";
+            const conf_file = std.fs.cwd().openFile(confpath, .{}) catch {
+                log.warn("Could not load config file '{s}'. Using default config.", .{confpath});
+                Config.loadDefault(allocator);
+                break :blk;
+            };
+            defer conf_file.close();
+
+            Config.load(allocator, conf_file.reader(), std.io.getStdErr().writer()) catch |err| {
+                log.err("Could not parse config file '{s}': {s}.", .{ confpath, @errorName(err) });
+                return 1;
+            };
+        }
+        defer Config.destroy(allocator);
+
+        const ver = lj.getDriverVersion();
+        std.debug.print("Driver version: {d}\n", .{ver});
+
+        RotCtl.run(allocator) catch |err| {
+            log.err("rotator controller ceased unexpectedly! {s}", .{@errorName(err)});
             return 1;
         };
+
+        return 0;
+    } else {
+        printHelp();
+        return 1;
     }
-    defer Config.destroy(allocator);
+}
 
-    const ver = lj.getDriverVersion();
-    std.debug.print("Driver version: {d}\n", .{ver});
+fn installUdevRules(outpath: ?[]const u8) u8 {
+    const rules_path = outpath orelse "/etc/udev/rules.d";
+    var rules_d = std.fs.cwd().openDir(rules_path, .{}) catch |err| {
+        printStderr(
+            "could not open udev rules path '{s}': {s}",
+            .{ rules_path, @errorName(err) },
+        );
+        return 1;
+    };
+    defer rules_d.close();
 
-    RotCtl.run(allocator) catch |err| {
-        log.err("rotator controller ceased unexpectedly! {s}", .{@errorName(err)});
+    rules_d.writeFile(.{ .sub_path = udev.rules_filename, .data = udev.rules }) catch |err| {
+        printStderr(
+            "could not write rules file '{s}{s}{s}': {s}",
+            .{
+                rules_path,
+                if (rules_path.len == 0)
+                    "./"
+                else if (rules_path[rules_path.len - 1] == '/')
+                    ""
+                else
+                    "/",
+                udev.rules_filename,
+                @errorName(err),
+            },
+        );
         return 1;
     };
 
     return 0;
 }
+
+fn writeDefaultConfig(outarg: ?[]const u8) u8 {
+    const outpath = outarg orelse "yaes.json";
+
+    const outfile = std.fs.cwd().createFile(outpath, .{}) catch |err| {
+        printStderr("Could not write config file '{s}': {s}", .{ outpath, @errorName(err) });
+        return 1;
+    };
+    defer outfile.close();
+
+    std.json.stringify(Config.global.*, .{ .whitespace = .indent_4 }, outfile.writer()) catch |err| {
+        printStderr("Could not serialize config file '{s}': {s}", .{ outpath, @errorName(err) });
+        return 1;
+    };
+
+    printStderr("config written to {s}", .{outpath});
+    return 0;
+}
+
+fn printHelp() void {
+    printStderr(
+        \\Usage: yaes [command] [args...]
+        \\
+        \\  Control a Yaesu G-5500DC rotator through a LabJack U12 using the hamlib TCP interface.
+        \\
+        \\Available commands:
+        \\
+    , .{});
+
+    inline for (@typeInfo(@TypeOf(commands)).Struct.fields) |field| {
+        printStderr(
+            "  {s} {s}",
+            .{ @field(commands, field.name), @field(command_help, field.name) },
+        );
+    }
+}