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libipc-old/zig-impl/src/context.zig

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Zig

const std = @import("std");
const hexdump = @import("./hexdump.zig");
const testing = std.testing;
const net = std.net;
const os = std.os;
const fmt = std.fmt;
const receive_fd = @import("./exchange-fd.zig").receive_fd;
const Timer = std.time.Timer;
const print = std.debug.print;
const CBEvent = @import("./callback.zig").CBEvent;
const Connection = @import("./connection.zig").Connection;
const Message = @import("./message.zig").Message;
const Event = @import("./event.zig").Event;
const Switch = @import("./switch.zig").Switch;
const print_eq = @import("./util.zig").print_eq;
const Messages = @import("./message.zig").Messages;
const Switches = @import("./switch.zig").Switches;
const Connections = @import("./connection.zig").Connections;
pub const PollFD = std.ArrayList(std.os.pollfd);
pub const IPC_HEADER_SIZE = 5; // Size (5 bytes) then content.
pub const IPC_BASE_SIZE = 2000000; // 2 MB, plenty enough space for messages
pub const IPC_MAX_MESSAGE_SIZE = IPC_BASE_SIZE-IPC_HEADER_SIZE;
pub const IPC_VERSION = 1;
// Context of the whole networking state.
pub const Context = struct {
rundir: [] u8,
allocator: std.mem.Allocator, // Memory allocator.
connections: Connections, // Keep track of connections.
// "pollfd" structures passed to poll(2). Same indexes as "connections".
pollfd: PollFD, // .fd (fd_t) + .events (i16) + .revents (i16)
tx: Messages, // Messages to send, once their fd is available.
switchdb: Switches, // Relations between fd.
timer: ?i32 = null, // No timer by default (no TIMER event).
const Self = @This();
// Context initialization:
// - init structures (provide the allocator)
pub fn init(allocator: std.mem.Allocator) !Self {
var rundir = std.process.getEnvVarOwned(allocator, "RUNDIR") catch |err| switch(err) {
error.EnvironmentVariableNotFound => blk: {
break :blk try allocator.dupeZ(u8, "/tmp/libipc-run/");
},
else => {
return err;
},
};
return Self {
.rundir = rundir
, .connections = Connections.init(allocator)
, .pollfd = PollFD.init(allocator)
, .tx = Messages.init(allocator)
, .switchdb = try Switches.init(allocator)
, .allocator = allocator
};
}
// create a server path for the UNIX socket based on the service name
pub fn server_path(self: *Self, service_name: []const u8, writer: anytype) !void {
try writer.print("{s}/{s}", .{self.rundir, service_name});
}
pub fn deinit(self: *Self) void {
self.close_all() catch |err| switch(err){
error.IndexOutOfBounds => {
print("context.deinit(): IndexOutOfBounds\n", .{});
},
};
self.allocator.free(self.rundir);
self.connections.deinit();
self.pollfd.deinit();
for (self.tx.items) |m| {
m.deinit();
}
self.tx.deinit();
self.switchdb.deinit();
}
// Both simple connection and the switched one share this code.
fn connect_ (self: *Self, ctype: Connection.Type, path: []const u8) !i32 {
var stream = try net.connectUnixSocket(path);
const newfd = stream.handle;
errdefer std.os.closeSocket(newfd);
var newcon = Connection.init(ctype, null);
try self.add_ (newcon, newfd);
return newfd;
}
fn connect_ipcd (self: *Self, service_name: []const u8
, connection_type: Connection.Type) !?i32 {
const buffer_size = 10000;
var buffer: [buffer_size]u8 = undefined;
var fba = std.heap.FixedBufferAllocator.init(&buffer);
var allocator = fba.allocator();
// Get IPC_NETWORK environment variable
// IPC_NETWORK is shared with the network service to choose the protocol stack,
// according to the target service.
//
// Example, connecting to 'audio' service through tor service:
// IPC_NETWORK="audio tor://some.example.com/audio"
//
// Routing directives can be chained using " ;" separator:
// IPC_NETWORK="audio https://example.com/audio ;pong tls://pong.example.com/pong"
var network_envvar = std.process.getEnvVarOwned(allocator, "IPC_NETWORK") catch |err| switch(err) {
// error{ OutOfMemory, EnvironmentVariableNotFound, InvalidUtf8 } (ErrorSet)
error.EnvironmentVariableNotFound => {
print("no IPC_NETWORK envvar: IPCd won't be contacted\n", .{});
return null;
}, // no need to contact IPCd
else => { return err; },
};
var lookupbuffer: [buffer_size]u8 = undefined;
var lookupfbs = std.io.fixedBufferStream(&lookupbuffer);
var lookupwriter = lookupfbs.writer();
try lookupwriter.print("{s};{s}", .{service_name, network_envvar});
// Try to connect to the IPCd service
var ipcdfd = try self.connect_service("ipc");
defer self.close_fd (ipcdfd) catch {}; // in any case, connection should be closed
// Send LOOKUP message
// content: target service name;${IPC_NETWORK}
// example: pong;pong tls://example.com:8998/pong
var m = try Message.init (ipcdfd, allocator, lookupfbs.getWritten());
try self.write (m);
// Read LOOKUP response
// case error: ignore and move on (TODO)
// else: get fd sent by IPCd then close IPCd fd
var reception_buffer: [2000]u8 = undefined;
var reception_size: usize = 0;
var newfd = try receive_fd (ipcdfd, &reception_buffer, &reception_size);
if (reception_size == 0) {
return error.IPCdFailedNoMessage;
}
var response: []u8 = reception_buffer[0..reception_size];
// print ("receive_fd:message received: {s} (len: {})\n", .{response, reception_size});
if (! std.mem.eql(u8, response, "ok")) {
return error.IPCdFailedNotOk;
}
var newcon = Connection.init(connection_type, null);
try self.add_ (newcon, newfd);
return newfd;
}
/// TODO: Add a new connection, but takes care of memory problems:
/// in case one of the arrays cannot sustain another entry, the other
/// won't be added.
fn add_ (self: *Self, new_connection: Connection, fd: os.socket_t) !void {
try self.connections.append(new_connection);
try self.pollfd.append(.{ .fd = fd
, .events = std.os.linux.POLL.IN
, .revents = 0 });
}
fn fd_to_index (self: Self, fd: i32) !usize {
var i: usize = 0;
while(i < self.pollfd.items.len) {
if (self.pollfd.items[i].fd == fd) {
return i;
}
i += 1;
}
return error.IndexNotFound;
}
// Return the new fd. Can be useful to the caller.
pub fn connect(self: *Self, path: []const u8) !i32 {
return self.connect_ (Connection.Type.IPC, path);
}
pub fn connect_service (self: *Self, service_name: []const u8) !i32 {
var buffer: [1000]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
try self.server_path(service_name, writer);
var path = fbs.getWritten();
return self.connect(path);
}
pub fn connect_ipc (self: *Self, service_name: []const u8) !i32 {
// First, try ipcd.
if (try self.connect_ipcd (service_name, Connection.Type.IPC)) |fd| {
print("Connected via IPCd, fd is {}\n", .{fd});
return fd;
}
// In case this doesn't work, connect directly.
return try self.connect_service (service_name);
}
// Connection to a service, but with switched with the client fd.
// pub fn connection_switched(self: *Self
// , path: [] const u8
// , clientfd: i32) !i32 {
// // print("connection switched from {} to path {s}\n", .{clientfd, path});
// var newfd = try self.connect_ (Connection.Type.SWITCHED, path);
// // TODO: record switch.
// return newfd;
// }
pub fn accept_new_client(self: *Self, event: *Event, server_index: usize) !void {
// net.StreamServer
var serverfd = self.pollfd.items[server_index].fd;
var path = self.connections.items[server_index].path orelse return error.ServerWithNoPath;
var server = net.StreamServer {
.sockfd = serverfd
, .kernel_backlog = 100
, .reuse_address = false
, .listen_address = try net.Address.initUnix(path)
};
var client = try server.accept(); // net.StreamServer.Connection
const newfd = client.stream.handle;
var newcon = Connection.init(Connection.Type.IPC, null);
try self.add_ (newcon, newfd);
const sfd = server.sockfd orelse return error.SocketLOL; // TODO
// WARNING: imply every new item is last
event.set(Event.Type.CONNECTION, self.pollfd.items.len - 1, sfd, null);
}
// Create a unix socket.
// Store std lib structures in the context.
pub fn server_init(self: *Self, service_name: [] const u8) !net.StreamServer {
var buffer: [1000]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
try self.server_path(service_name, writer);
var path = fbs.getWritten();
// print("context server init {s}\n", .{path});
var server = net.StreamServer.init(.{});
var socket_addr = try net.Address.initUnix(path);
try server.listen(socket_addr);
const newfd = server.sockfd orelse return error.SocketLOL; // TODO
// Store the path in the Connection structure, so the UNIX socket file can be removed later.
var newcon = Connection.init(Connection.Type.SERVER, try self.allocator.dupeZ(u8, path));
try self.add_ (newcon, newfd);
return server;
}
pub fn write (_: *Self, m: Message) !void {
// Message contains the fd, no need to search for
// the right structure to copy, let's just recreate
// a Stream from the fd.
var stream = net.Stream { .handle = m.fd };
var buffer: [IPC_MAX_MESSAGE_SIZE]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
_ = try m.write(writer); // returns paylen
_ = try stream.write (fbs.getWritten());
}
pub fn schedule (self: *Self, m: Message) !void {
try self.tx.append(m);
}
pub fn read (self: *Self, index: usize) !?Message {
if (index >= self.pollfd.items.len) {
return error.IndexOutOfBounds;
}
var buffer: [IPC_MAX_MESSAGE_SIZE]u8 = undefined; // TODO: FIXME??
var packet_size: usize = undefined;
// TODO: this is a problem from the network API in Zig,
// servers and clients are different, they aren't just fds.
// Maybe there is something to change in the API.
if (self.connections.items[index].t == .SERVER) {
return error.messageOnServer;
}
// This may be kinda hacky, idk.
var fd = self.pollfd.items[index].fd;
var stream: net.Stream = .{ .handle = fd };
packet_size = try stream.read(buffer[0..]);
// Let's handle this as a disconnection.
if (packet_size <= 4) {
return null;
}
return try Message.read(fd, buffer[0..], self.allocator);
}
// Wait for an event.
pub fn wait_event(self: *Self) !Event {
var current_event: Event = Event.init(Event.Type.ERROR, 0, 0, null);
var wait_duration: i32 = -1; // -1 == unlimited
if (self.timer) |t| { wait_duration = t; }
else { print("listening (no timer)\n", .{}); }
// Make sure we listen to the right file descriptors,
// setting POLLIN & POLLOUT flags.
for (self.pollfd.items) |*fd| {
fd.events |= std.os.linux.POLL.IN; // just to make sure
}
for (self.tx.items) |m| {
for (self.pollfd.items) |*fd| {
if (fd.fd == m.fd) {
fd.events |= std.os.linux.POLL.OUT; // just to make sure
}
}
}
// before initiate a timer
var timer = try Timer.start();
// Polling.
var count: usize = undefined;
// print("fds: {any}\n", .{self.pollfd.items});
count = try os.poll(self.pollfd.items, wait_duration);
// print("fds NOW: {any}\n", .{self.pollfd.items});
if (count < 0) {
print("there is a problem: poll < 0\n", .{});
current_event = Event.init(Event.Type.ERROR, 0, 0, null);
return current_event;
}
var duration = timer.read() / 1000000; // ns -> ms
if (count == 0) {
if (duration >= wait_duration) {
current_event = Event.init(Event.Type.TIMER, 0, 0, null);
}
else {
// In case nothing happened, and poll wasn't triggered by time out.
current_event = Event.init(Event.Type.ERROR, 0, 0, null);
}
return current_event;
}
// handle messages
// => loop over self.pollfd.items
for (self.pollfd.items) |*fd, i| {
// .revents is POLLIN
if(fd.revents & std.os.linux.POLL.IN > 0) {
// SERVER = new connection
if (self.connections.items[i].t == .SERVER) {
try self.accept_new_client(&current_event, i);
return current_event;
}
// SWITCHED = send message to the right dest (or drop the switch)
else if (self.connections.items[i].t == .SWITCHED) {
// TODO: read message from fd.fd + schedule read message
return Event.init(Event.Type.SWITCH, i, fd.fd, null);
}
// EXTERNAL = user handles IO
else if (self.connections.items[i].t == .EXTERNAL) {
return Event.init(Event.Type.EXTERNAL, i, fd.fd, null);
}
// otherwise = new message or disconnection
else {
var maybe_message = self.read(i) catch |err| switch(err) {
error.ConnectionResetByPeer => {
print("connection reset by peer\n", .{});
try self.close(i);
return Event.init(Event.Type.DISCONNECTION, i, fd.fd, null);
},
else => { return err; },
};
if (maybe_message) |m| {
return Event.init(Event.Type.MESSAGE, i, fd.fd, m);
}
try self.close(i);
return Event.init(Event.Type.DISCONNECTION, i, fd.fd, null);
}
}
// .revent is POLLOUT
if(fd.revents & std.os.linux.POLL.OUT > 0) {
fd.events &= ~ @as(i16, std.os.linux.POLL.OUT);
// SWITCHED = write message for its switch buddy (callbacks)
if (self.connections.items[i].t == .SWITCHED) {
// TODO: write message
return Event.init(Event.Type.SWITCH, i, fd.fd, null);
}
else {
// otherwise = write message for the msg.fd
var index: usize = undefined;
for (self.tx.items) |m, index_| {
if (m.fd == self.pollfd.items[i].fd) {
index = index_;
break;
}
}
var m = self.tx.swapRemove(index);
try self.write (m);
m.deinit();
return Event.init(Event.Type.TX, i, fd.fd, null);
}
}
// .revent is POLLHUP
if(fd.revents & std.os.linux.POLL.HUP > 0) {
// handle disconnection
current_event = Event.init(Event.Type.DISCONNECTION, i, fd.fd, null);
try self.close(i);
return current_event;
}
// if fd revent is POLLERR or POLLNVAL
if ((fd.revents & std.os.linux.POLL.HUP > 0) or
(fd.revents & std.os.linux.POLL.NVAL > 0)) {
return Event.init(Event.Type.ERROR, i, fd.fd, null);
}
}
return current_event;
}
/// Remove a connection based on its file descriptor.
pub fn close_fd(self: *Self, fd: i32) !void {
try self.close(try self.fd_to_index (fd));
}
pub fn close(self: *Self, index: usize) !void {
// REMINDER: connections and pollfd have the same length
if (index >= self.pollfd.items.len) {
return error.IndexOutOfBounds;
}
// close the connection and remove it from the two structures
var con = self.connections.swapRemove(index);
// Remove service's UNIX socket file.
if (con.path) |path| {
std.fs.cwd().deleteFile(path) catch {};
self.allocator.free(path);
}
var pollfd = self.pollfd.swapRemove(index);
std.os.close(pollfd.fd);
// Remove all its non-sent messages.
var i: usize = 0;
while (true) {
if (i >= self.tx.items.len)
break;
if (self.tx.items[i].fd == pollfd.fd) {
var m = self.tx.swapRemove(i);
m.deinit();
continue;
}
i += 1;
}
}
pub fn close_all(self: *Self) !void {
while(self.connections.items.len > 0) { try self.close(0); }
}
pub fn format(self: Self, comptime form: []const u8, options: fmt.FormatOptions, out_stream: anytype) !void {
try fmt.format(out_stream
, "context ({} connections and {} messages):"
, .{self.connections.items.len, self.tx.items.len});
for (self.connections.items) |con| {
try fmt.format(out_stream, "\n- ", .{});
try con.format(form, options, out_stream);
}
for (self.tx.items) |tx| {
try fmt.format(out_stream, "\n- ", .{});
try tx.format(form, options, out_stream);
}
}
};
//test "Simple structures - init, display and memory check" {
// // origin destination
// var s = Switch.init(3,8);
// var payload = "hello!!";
// // fd type payload
// var m = Message.init(0, allocator, payload);
//
// // type index origin message
// var e = Event.init(Event.Type.CONNECTION, 5, 8, &m);
// // CLIENT SIDE: connection to a service.
// _ = try c.connect(path);
// // TODO: connection to a server, but switched with clientfd "3".
// _ = try c.connection_switched(path, 3);
//}
// Creating a new thread: testing UNIX communication.
// This is a client sending a raw "Hello world!" bytestring,
// not an instance of Message.
const CommunicationTestThread = struct {
fn clientFn() !void {
const config = .{.safety = true};
var gpa = std.heap.GeneralPurposeAllocator(config){};
defer _ = gpa.deinit();
const allocator = gpa.allocator();
var c = try Context.init(allocator);
defer c.deinit(); // There. Can't leak. Isn't Zig wonderful?
var buffer: [1000]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
try c.server_path("simple-context-test", writer);
var path = fbs.getWritten();
const socket = try net.connectUnixSocket(path);
defer socket.close();
_ = try socket.writer().writeAll("Hello world!");
}
};
test "Context - creation, display and memory check" {
const config = .{.safety = true};
var gpa = std.heap.GeneralPurposeAllocator(config){};
defer _ = gpa.deinit();
const allocator = gpa.allocator();
var c = try Context.init(allocator);
defer c.deinit(); // There. Can't leak. Isn't Zig wonderful?
var buffer: [1000]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
try c.server_path("simple-context-test", writer);
var path = fbs.getWritten();
// SERVER SIDE: creating a service.
var server = c.server_init("simple-context-test") catch |err| switch(err) {
error.FileNotFound => {
print ("\nError: cannot init server at {s}\n", .{path});
return err;
},
else => return err,
};
defer std.fs.cwd().deleteFile(path) catch {}; // Once done, remove file.
const t = try std.Thread.spawn(.{}, CommunicationTestThread.clientFn, .{});
defer t.join();
// Server.accept returns a net.StreamServer.Connection.
var client = try server.accept();
defer client.stream.close();
var buf: [16]u8 = undefined;
const n = try client.stream.reader().read(&buf);
try testing.expectEqual(@as(usize, 12), n);
try testing.expectEqualSlices(u8, "Hello world!", buf[0..n]);
}
// Creating a new thread: testing UNIX communication.
// This is a client sending a an instance of Message.
const ConnectThenSendMessageThread = struct {
fn clientFn() !void {
const config = .{.safety = true};
var gpa = std.heap.GeneralPurposeAllocator(config){};
defer _ = gpa.deinit();
const allocator = gpa.allocator();
var c = try Context.init(allocator);
defer c.deinit(); // There. Can't leak. Isn't Zig wonderful?
var path_buffer: [1000]u8 = undefined;
var path_fbs = std.io.fixedBufferStream(&path_buffer);
var path_writer = path_fbs.writer();
try c.server_path("simple-context-test", path_writer);
var path = path_fbs.getWritten();
// Actual UNIX socket connection.
const socket = try net.connectUnixSocket(path);
defer socket.close();
// Writing message into a buffer.
var message_buffer: [1000]u8 = undefined;
var message_fbs = std.io.fixedBufferStream(&message_buffer);
var message_writer = message_fbs.writer();
// 'fd' parameter is not taken into account here (no loop)
var m = try Message.init(0, allocator, "Hello world!");
defer m.deinit();
_ = try m.write(message_writer);
_ = try socket.writer().writeAll(message_fbs.getWritten());
}
};
test "Context - creation, echo once" {
const config = .{.safety = true};
var gpa = std.heap.GeneralPurposeAllocator(config){};
defer _ = gpa.deinit();
const allocator = gpa.allocator();
var c = try Context.init(allocator);
defer c.deinit(); // There. Can't leak. Isn't Zig wonderful?
var buffer: [1000]u8 = undefined;
var fbs = std.io.fixedBufferStream(&buffer);
var writer = fbs.writer();
try c.server_path("simple-context-test", writer);
var path = fbs.getWritten();
// SERVER SIDE: creating a service.
var server = c.server_init("simple-context-test") catch |err| switch(err) {
error.FileNotFound => {
print ("\nError: cannot init server at {s}\n", .{path});
return err;
},
else => return err,
};
defer std.fs.cwd().deleteFile(path) catch {}; // Once done, remove file.
const t = try std.Thread.spawn(.{}, ConnectThenSendMessageThread.clientFn, .{});
defer t.join();
// Server.accept returns a net.StreamServer.Connection.
var client = try server.accept();
defer client.stream.close();
var buf: [1000]u8 = undefined;
const n = try client.stream.reader().read(&buf);
var m = try Message.read(8, buf[0..n], allocator); // 8 == random client's fd number
defer m.deinit();
try testing.expectEqual(@as(usize, 12), m.payload.len);
try testing.expectEqualSlices(u8, m.payload, "Hello world!");
}