Source/SocketWrapper.m

   1 /*
   2  * MacGDBp
   3  * Copyright (c) 2002 - 2007, Blue Static <http://www.bluestatic.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it under the terms of the GNU
   6  * General Public License as published by the Free Software Foundation; either version 2 of the
   7  * License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
  10  * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with this program; if not,
  14  * write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  15  */
  16
  17 #import "SocketWrapper.h"
  18 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <arpa/inet.h>
  22 #include <unistd.h>
  23
  24 NSString *sockNotificationDebuggerConnection = @"DebuggerConnection";
  25 NSString *sockNotificationReceiver = @"SEL-del-SocketWrapper_dataReceived";
  26 NSString *NsockError = @"SocketWrapper_Error";
  27 NSString *NsockDidAccept = @"SocketWrapper_DidAccept";
  28 NSString *NsockDataReceived = @"SocketWrapper_DataReceived";
  29 NSString *NsockDataSent = @"SocketWrapper_DataSent";
  30
  31 @implementation SocketWrapper
  32
  33 /**
  34  * Initializes the socket wrapper with a host and port
  35  */
  36 - (id)initWithPort: (int)port
  37 {
  38         if (self = [super init])
  39         {
  40                 _port = port;
  41
  42                 // the delegate notifications work funky because of threads. we register ourselves as the
  43                 // observer and then pass up the messages that are actually from this object (as we can't only observe self due to threads)
  44                 // to our delegate, and not to all delegates
  45                 [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(_sendMessageToDelegate:) name: nil object: nil];
  46         }
  47         return self;
  48 }
  49
  50 /**
  51  * Close our socket and clean up anything else
  52  */
  53 - (void)dealloc
  54 {
  55         close(_socket);
  56
  57         [super dealloc];
  58 }
  59
  60 /**
  61  * Returns the delegate
  62  */
  63 - (id)delegate
  64 {
  65         return _delegate;
  66 }
  67
  68 /**
  69  * Sets the delegate but does *not* retain it
  70  */
  71 - (void)setDelegate: (id)delegate
  72 {
  73         _delegate = delegate;
  74 }
  75
  76 /**
  77  * This is the notification listener for all types of notifications. If the notifications are from a SocketWrapper
  78  * class, it checks that the value of _delegate in the NSNotification's userInfo matches that of this object. If it does,
  79  * then the notification was sent from the same object in another thread and it passes the message along to the object's
  80  * delegate. Complicated enough?
  81  */
  82 - (void)_sendMessageToDelegate: (NSNotification *)notif
  83 {
  84         // this isn't us, so there's no point in continuing
  85         if ([[notif userInfo] objectForKey: sockNotificationDebuggerConnection] != _delegate)
  86         {
  87                 return;
  88         }
  89
  90         NSString *name = [notif name];
  91
  92         if (name == NsockDidAccept)
  93         {
  94                 [_delegate socketDidAccept];
  95         }
  96         else if (name == NsockDataReceived)
  97         {
  98                 [_delegate dataReceived: [notif object] deliverTo: NSSelectorFromString([[notif userInfo] objectForKey: sockNotificationReceiver])];
  99         }
 100         else if (name == NsockDataSent)
 101         {
 102                 [_delegate dataSent];
 103         }
 104         else if (name == NsockError)
 105         {
 106                 [_delegate errorEncountered: [NSError errorWithDomain: [notif object] code: -1 userInfo: nil]];
 107         }
 108 }
 109
 110 /**
 111  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
 112  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
 113  */
 114 - (void)connect
 115 {
 116         [NSThread detachNewThreadSelector: @selector(_connect:) toTarget: self withObject: nil];
 117 }
 118
 119 /**
 120  * This does the actual dirty work (in a separate thread) of connecting to a socket
 121  */
 122 - (void)_connect: (id)obj
 123 {
 124         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 125
 126         // create an INET socket that we'll be listen()ing on
 127         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
 128
 129         // create our address given the port
 130         struct sockaddr_in address;
 131         address.sin_family = AF_INET;
 132         address.sin_port = htons(_port);
 133         address.sin_addr.s_addr = htonl(INADDR_ANY);
 134         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 135
 136         // bind the socket... and don't give up until we've tried for a while
 137         int tries = 0;
 138         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 139         {
 140                 if (tries >= 5)
 141                 {
 142                         close(socketOpen);
 143                         [self _postNotification: NsockError withObject: @"Could not bind to socket"];
 144                 }
 145                 NSLog(@"couldn't bind to the socket... trying again in 5");
 146                 sleep(5);
 147                 tries++;
 148         }
 149
 150         // now we just have to keep our ears open
 151         if (listen(socketOpen, 0) == -1)
 152         {
 153                 [self _postNotification: NsockError withObject: @"Could not use bound socket for listening"];
 154         }
 155
 156         // accept a connection
 157         struct sockaddr_in remoteAddress;
 158         socklen_t remoteAddressLen = sizeof(remoteAddress);
 159         _socket = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 160         if (_socket < 0)
 161         {
 162                 close(socketOpen);
 163                 [self _postNotification: NsockError withObject: @"Client failed to accept remote socket"];
 164         }
 165
 166         // we're done listening now that we have a connection
 167         close(socketOpen);
 168
 169         [self _postNotification: NsockDidAccept withObject: nil];
 170
 171         [pool release];
 172 }
 173
 174 /**
 175  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 176  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 177  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 178  * will return something (which we almost always do).
 179  *
 180  * The paramater is an optional selector which the delegate method dataReceived:deliverTo: should forward to
 181  */
 182 - (void)receive: (SEL)selector
 183 {
 184         // create a buffer
 185         char buffer[1024];
 186
 187         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 188         int recvd = recv(_socket, &buffer, sizeof(buffer), 0);
 189
 190         // take the received data and put it into an NSData
 191         NSMutableData *data = [NSMutableData data];
 192
 193         // strip the length from the packet, and clear the null byte then add it to the NSData
 194         char packetLength[8];
 195         int i = 0;
 196         while (buffer[i] != '\0')
 197         {
 198                 packetLength[i] = buffer[i];
 199                 i++;
 200         }
 201
 202         // we also want the null byte, so move us up 1
 203         i++;
 204
 205         // the total length of the full transmission
 206         int length = atoi(packetLength);
 207
 208         // move the packet part of the received data into it's own char[]
 209         char packet[sizeof(buffer)];
 210         memmove(packet, &buffer[i], recvd - i);
 211
 212         // convert bytes to NSData
 213         [data appendBytes: packet length: recvd];
 214
 215         // check if we have a partial packet
 216         if (length + i > sizeof(buffer))
 217         {
 218                 while (recvd < length)
 219                 {
 220                         int latest = recv(_socket, &buffer, sizeof(buffer), 0);
 221                         if (latest < 1)
 222                         {
 223                                 [self _postNotification: NsockError withObject: @"Socket closed or could not be read"];
 224                         }
 225                         [data appendBytes: buffer length: latest];
 226                         recvd += latest;
 227                 }
 228         }
 229
 230         // convert the NSData into a NSString
 231         NSString *string = [[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding] autorelease];
 232
 233         [self _postNotification: NsockDataReceived
 234                                  withObject: string
 235                                    withDict: [NSMutableDictionary dictionaryWithObject: NSStringFromSelector(selector) forKey: sockNotificationReceiver]];
 236 }
 237
 238 /**
 239  * Sends a given NSString over the socket
 240  */
 241 - (void)send: (NSString *)data
 242 {
 243         data = [NSString stringWithFormat: @"%@\0", data];
 244         int sent = send(_socket, [data UTF8String], [data length], 0);
 245         if (sent < 0)
 246         {
 247                 [self _postNotification: NsockError withObject: @"Failed to write data to socket"];
 248         }
 249         if (sent < [data length])
 250         {
 251                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 252                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 253         }
 254
 255         [self _postNotification: NsockDataSent withObject: nil];
 256 }
 257
 258 /**
 259  * Helper method to simply post a notification to the default notification center with a given name and object
 260  */
 261 - (void)_postNotification: (NSString *)name withObject: (id)obj
 262 {
 263         [self _postNotification: name withObject: obj withDict: [NSMutableDictionary dictionary]];
 264 }
 265
 266 /**
 267  * Another helper method to aid in the posting of notifications. This one should be used if you have additional
 268  * things for the userInfo. This automatically adds the sockNotificationDebuggerConnection key.
 269  */
 270 - (void)_postNotification: (NSString *)name withObject: (id)obj withDict: (NSMutableDictionary *)dict
 271 {
 272         [dict setValue: _delegate forKey: sockNotificationDebuggerConnection];
 273         [[NSNotificationCenter defaultCenter] postNotificationName: name object: obj userInfo: dict];
 274 }
 275
 276 @end