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 @interface SocketWrapper (Private)
  32
  33 - (void)connect: (id)obj;
  34 - (void)postNotification: (NSString *)name withObject: (id)obj;
  35 - (void)postNotification: (NSString *)name withObject: (id)obj withDict: (NSMutableDictionary *)dict;
  36
  37 @end
  38
  39 @implementation SocketWrapper
  40
  41 /**
  42  * Initializes the socket wrapper with a host and port
  43  */
  44 - (id)initWithPort: (int)port
  45 {
  46         if (self = [super init])
  47         {
  48                 _port = port;
  49
  50                 // the delegate notifications work funky because of threads. we register ourselves as the
  51                 // observer and then pass up the messages that are actually from this object (as we can't only observe self due to threads)
  52                 // to our delegate, and not to all delegates
  53                 [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(sendMessageToDelegate:) name: nil object: nil];
  54         }
  55         return self;
  56 }
  57
  58 /**
  59  * Close our socket and clean up anything else
  60  */
  61 - (void)dealloc
  62 {
  63         close(_socket);
  64
  65         [super dealloc];
  66 }
  67
  68 /**
  69  * Returns the delegate
  70  */
  71 - (id)delegate
  72 {
  73         return _delegate;
  74 }
  75
  76 /**
  77  * Sets the delegate but does *not* retain it
  78  */
  79 - (void)setDelegate: (id)delegate
  80 {
  81         _delegate = delegate;
  82 }
  83
  84 /**
  85  * Returns the name of the host to whom we are currently connected.
  86  */
  87 - (NSString *)remoteHost
  88 {
  89         struct sockaddr_in addr;
  90         socklen_t addrLength;
  91
  92         if (getpeername(_socket, (struct sockaddr *)&addr, &addrLength) < 0)
  93         {
  94                 [self postNotification: NsockError withObject: [NSError errorWithDomain: @"Could not get remote hostname." code: -1 userInfo: nil]];
  95         }
  96
  97         char *name = inet_ntoa(addr.sin_addr);
  98
  99         return [NSString stringWithUTF8String: name];
 100 }
 101
 102 /**
 103  * This is the notification listener for all types of notifications. If the notifications are from a SocketWrapper
 104  * class, it checks that the value of _delegate in the NSNotification's userInfo matches that of this object. If it does,
 105  * then the notification was sent from the same object in another thread and it passes the message along to the object's
 106  * delegate. Complicated enough?
 107  */
 108 - (void)sendMessageToDelegate: (NSNotification *)notif
 109 {
 110         // this isn't us, so there's no point in continuing
 111         if ([[notif userInfo] objectForKey: sockNotificationDebuggerConnection] != _delegate)
 112         {
 113                 return;
 114         }
 115
 116         NSString *name = [notif name];
 117
 118         if (name == NsockDidAccept)
 119         {
 120                 [_delegate socketDidAccept];
 121         }
 122         else if (name == NsockDataReceived)
 123         {
 124                 [_delegate dataReceived: [notif object] deliverTo: NSSelectorFromString([[notif userInfo] objectForKey: sockNotificationReceiver])];
 125         }
 126         else if (name == NsockDataSent)
 127         {
 128                 [_delegate dataSent: [notif object]];
 129         }
 130         else if (name == NsockError)
 131         {
 132                 [_delegate errorEncountered: [NSError errorWithDomain: [notif object] code: -1 userInfo: nil]];
 133         }
 134 }
 135
 136 /**
 137  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
 138  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
 139  */
 140 - (void)connect
 141 {
 142         [NSThread detachNewThreadSelector: @selector(connect:) toTarget: self withObject: nil];
 143 }
 144
 145 /**
 146  * This does the actual dirty work (in a separate thread) of connecting to a socket
 147  */
 148 - (void)connect: (id)obj
 149 {
 150         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 151
 152         // create an INET socket that we'll be listen()ing on
 153         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
 154
 155         // create our address given the port
 156         struct sockaddr_in address;
 157         address.sin_family = AF_INET;
 158         address.sin_port = htons(_port);
 159         address.sin_addr.s_addr = htonl(INADDR_ANY);
 160         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 161
 162         // bind the socket... and don't give up until we've tried for a while
 163         int tries = 0;
 164         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 165         {
 166                 if (tries >= 5)
 167                 {
 168                         close(socketOpen);
 169                         [self postNotification: NsockError withObject: @"Could not bind to socket"];
 170                         return;
 171                 }
 172                 NSLog(@"couldn't bind to the socket... trying again in 5");
 173                 sleep(5);
 174                 tries++;
 175         }
 176
 177         // now we just have to keep our ears open
 178         if (listen(socketOpen, 0) == -1)
 179         {
 180                 [self postNotification: NsockError withObject: @"Could not use bound socket for listening"];
 181         }
 182
 183         // accept a connection
 184         struct sockaddr_in remoteAddress;
 185         socklen_t remoteAddressLen = sizeof(remoteAddress);
 186         _socket = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 187         if (_socket < 0)
 188         {
 189                 close(socketOpen);
 190                 [self postNotification: NsockError withObject: @"Client failed to accept remote socket"];
 191                 return;
 192         }
 193
 194         // we're done listening now that we have a connection
 195         close(socketOpen);
 196
 197         [self postNotification: NsockDidAccept withObject: nil];
 198
 199         [pool release];
 200 }
 201
 202 /**
 203  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 204  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 205  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 206  * will return something (which we almost always do).
 207  *
 208  * The paramater is an optional selector which the delegate method dataReceived:deliverTo: should forward to
 209  */
 210 - (void)receive: (SEL)selector
 211 {
 212         // create a buffer
 213         char buffer[1024];
 214
 215         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 216         int recvd = recv(_socket, &buffer, sizeof(buffer), 0);
 217
 218         // take the received data and put it into an NSData
 219         NSMutableData *data = [NSMutableData data];
 220
 221         // strip the length from the packet, and clear the null byte then add it to the NSData
 222         char packetLength[8];
 223         int i = 0;
 224         while (buffer[i] != '\0')
 225         {
 226                 packetLength[i] = buffer[i];
 227                 i++;
 228         }
 229
 230         // we also want the null byte, so move us up 1
 231         i++;
 232
 233         // the total length of the full transmission
 234         int length = atoi(packetLength);
 235
 236         // move the packet part of the received data into it's own char[]
 237         char packet[sizeof(buffer)];
 238         memmove(packet, &buffer[i], recvd - i);
 239
 240         // convert bytes to NSData
 241         [data appendBytes: packet length: recvd];
 242
 243         // check if we have a partial packet
 244         if (length + i > sizeof(buffer))
 245         {
 246                 while (recvd < length)
 247                 {
 248                         int latest = recv(_socket, &buffer, sizeof(buffer), 0);
 249                         if (latest < 1)
 250                         {
 251                                 [self postNotification: NsockError withObject: @"Socket closed or could not be read"];
 252                                 return;
 253                         }
 254                         [data appendBytes: buffer length: latest];
 255                         recvd += latest;
 256                 }
 257         }
 258
 259         if (selector != nil)
 260         {
 261                 [self postNotification: NsockDataReceived
 262                                          withObject: data
 263                                            withDict: [NSMutableDictionary dictionaryWithObject: NSStringFromSelector(selector) forKey: sockNotificationReceiver]];
 264         }
 265         else
 266         {
 267                 [self postNotification: NsockDataReceived withObject: data];
 268         }
 269 }
 270
 271 /**
 272  * Sends a given NSString over the socket
 273  */
 274 - (void)send: (NSString *)data
 275 {
 276         data = [NSString stringWithFormat: @"%@\0", data];
 277         int sent = send(_socket, [data UTF8String], [data length], 0);
 278         if (sent < 0)
 279         {
 280                 [self postNotification: NsockError withObject: @"Failed to write data to socket"];
 281                 return;
 282         }
 283         if (sent < [data length])
 284         {
 285                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 286                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 287         }
 288
 289         [self postNotification: NsockDataSent withObject: [data substringToIndex: sent]];
 290 }
 291
 292 /**
 293  * Helper method to simply post a notification to the default notification center with a given name and object
 294  */
 295 - (void)postNotification: (NSString *)name withObject: (id)obj
 296 {
 297         [self postNotification: name withObject: obj withDict: [NSMutableDictionary dictionary]];
 298 }
 299
 300 /**
 301  * Another helper method to aid in the posting of notifications. This one should be used if you have additional
 302  * things for the userInfo. This automatically adds the sockNotificationDebuggerConnection key.
 303  */
 304 - (void)postNotification: (NSString *)name withObject: (id)obj withDict: (NSMutableDictionary *)dict
 305 {
 306         [dict setValue: _delegate forKey: sockNotificationDebuggerConnection];
 307         [[NSNotificationCenter defaultCenter] postNotificationName: name object: obj userInfo: dict];
 308 }
 309
 310 @end