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  * Returns the name of the host to whom we are currently connected.
  78  */
  79 - (NSString *)remoteHost
  80 {
  81         struct sockaddr_in addr;
  82         socklen_t addrLength;
  83
  84         if (getpeername(_socket, (struct sockaddr *)&addr, &addrLength) < 0)
  85         {
  86                 [self _postNotification: NsockError withObject: [NSError errorWithDomain: @"Could not get remote hostname." code: -1 userInfo: nil]];
  87         }
  88
  89         char *name = inet_ntoa(addr.sin_addr);
  90
  91         return [NSString stringWithUTF8String: name];
  92 }
  93
  94 /**
  95  * This is the notification listener for all types of notifications. If the notifications are from a SocketWrapper
  96  * class, it checks that the value of _delegate in the NSNotification's userInfo matches that of this object. If it does,
  97  * then the notification was sent from the same object in another thread and it passes the message along to the object's
  98  * delegate. Complicated enough?
  99  */
 100 - (void)_sendMessageToDelegate: (NSNotification *)notif
 101 {
 102         // this isn't us, so there's no point in continuing
 103         if ([[notif userInfo] objectForKey: sockNotificationDebuggerConnection] != _delegate)
 104         {
 105                 return;
 106         }
 107
 108         NSString *name = [notif name];
 109
 110         if (name == NsockDidAccept)
 111         {
 112                 [_delegate socketDidAccept];
 113         }
 114         else if (name == NsockDataReceived)
 115         {
 116                 [_delegate dataReceived: [notif object] deliverTo: NSSelectorFromString([[notif userInfo] objectForKey: sockNotificationReceiver])];
 117         }
 118         else if (name == NsockDataSent)
 119         {
 120                 [_delegate dataSent];
 121         }
 122         else if (name == NsockError)
 123         {
 124                 [_delegate errorEncountered: [NSError errorWithDomain: [notif object] code: -1 userInfo: nil]];
 125         }
 126 }
 127
 128 /**
 129  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
 130  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
 131  */
 132 - (void)connect
 133 {
 134         [NSThread detachNewThreadSelector: @selector(_connect:) toTarget: self withObject: nil];
 135 }
 136
 137 /**
 138  * This does the actual dirty work (in a separate thread) of connecting to a socket
 139  */
 140 - (void)_connect: (id)obj
 141 {
 142         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 143
 144         // create an INET socket that we'll be listen()ing on
 145         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
 146
 147         // create our address given the port
 148         struct sockaddr_in address;
 149         address.sin_family = AF_INET;
 150         address.sin_port = htons(_port);
 151         address.sin_addr.s_addr = htonl(INADDR_ANY);
 152         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 153
 154         // bind the socket... and don't give up until we've tried for a while
 155         int tries = 0;
 156         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 157         {
 158                 if (tries >= 5)
 159                 {
 160                         close(socketOpen);
 161                         [self _postNotification: NsockError withObject: @"Could not bind to socket"];
 162                         return;
 163                 }
 164                 NSLog(@"couldn't bind to the socket... trying again in 5");
 165                 sleep(5);
 166                 tries++;
 167         }
 168
 169         // now we just have to keep our ears open
 170         if (listen(socketOpen, 0) == -1)
 171         {
 172                 [self _postNotification: NsockError withObject: @"Could not use bound socket for listening"];
 173         }
 174
 175         // accept a connection
 176         struct sockaddr_in remoteAddress;
 177         socklen_t remoteAddressLen = sizeof(remoteAddress);
 178         _socket = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 179         if (_socket < 0)
 180         {
 181                 close(socketOpen);
 182                 [self _postNotification: NsockError withObject: @"Client failed to accept remote socket"];
 183                 return;
 184         }
 185
 186         // we're done listening now that we have a connection
 187         close(socketOpen);
 188
 189         [self _postNotification: NsockDidAccept withObject: nil];
 190
 191         [pool release];
 192 }
 193
 194 /**
 195  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 196  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 197  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 198  * will return something (which we almost always do).
 199  *
 200  * The paramater is an optional selector which the delegate method dataReceived:deliverTo: should forward to
 201  */
 202 - (void)receive: (SEL)selector
 203 {
 204         // create a buffer
 205         char buffer[1024];
 206
 207         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 208         int recvd = recv(_socket, &buffer, sizeof(buffer), 0);
 209
 210         // take the received data and put it into an NSData
 211         NSMutableData *data = [NSMutableData data];
 212
 213         // strip the length from the packet, and clear the null byte then add it to the NSData
 214         char packetLength[8];
 215         int i = 0;
 216         while (buffer[i] != '\0')
 217         {
 218                 packetLength[i] = buffer[i];
 219                 i++;
 220         }
 221
 222         // we also want the null byte, so move us up 1
 223         i++;
 224
 225         // the total length of the full transmission
 226         int length = atoi(packetLength);
 227
 228         // move the packet part of the received data into it's own char[]
 229         char packet[sizeof(buffer)];
 230         memmove(packet, &buffer[i], recvd - i);
 231
 232         // convert bytes to NSData
 233         [data appendBytes: packet length: recvd];
 234
 235         // check if we have a partial packet
 236         if (length + i > sizeof(buffer))
 237         {
 238                 while (recvd < length)
 239                 {
 240                         int latest = recv(_socket, &buffer, sizeof(buffer), 0);
 241                         if (latest < 1)
 242                         {
 243                                 [self _postNotification: NsockError withObject: @"Socket closed or could not be read"];
 244                                 return;
 245                         }
 246                         [data appendBytes: buffer length: latest];
 247                         recvd += latest;
 248                 }
 249         }
 250
 251         // convert the NSData into a NSString
 252         NSString *string = [[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding] autorelease];
 253
 254         [self _postNotification: NsockDataReceived
 255                                  withObject: string
 256                                    withDict: [NSMutableDictionary dictionaryWithObject: NSStringFromSelector(selector) forKey: sockNotificationReceiver]];
 257 }
 258
 259 /**
 260  * Sends a given NSString over the socket
 261  */
 262 - (void)send: (NSString *)data
 263 {
 264         data = [NSString stringWithFormat: @"%@\0", data];
 265         int sent = send(_socket, [data UTF8String], [data length], 0);
 266         if (sent < 0)
 267         {
 268                 [self _postNotification: NsockError withObject: @"Failed to write data to socket"];
 269                 return;
 270         }
 271         if (sent < [data length])
 272         {
 273                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 274                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 275         }
 276
 277         [self _postNotification: NsockDataSent withObject: nil];
 278 }
 279
 280 /**
 281  * Helper method to simply post a notification to the default notification center with a given name and object
 282  */
 283 - (void)_postNotification: (NSString *)name withObject: (id)obj
 284 {
 285         [self _postNotification: name withObject: obj withDict: [NSMutableDictionary dictionary]];
 286 }
 287
 288 /**
 289  * Another helper method to aid in the posting of notifications. This one should be used if you have additional
 290  * things for the userInfo. This automatically adds the sockNotificationDebuggerConnection key.
 291  */
 292 - (void)_postNotification: (NSString *)name withObject: (id)obj withDict: (NSMutableDictionary *)dict
 293 {
 294         [dict setValue: _delegate forKey: sockNotificationDebuggerConnection];
 295         [[NSNotificationCenter defaultCenter] postNotificationName: name object: obj userInfo: dict];
 296 }
 297
 298 @end