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)initWithConnection:(DebuggerConnection *)cnx
  45 {
  46         if (self = [super init])
  47         {
  48                 connection = cnx;
  49                 port = [connection port];
  50
  51                 // the delegate notifications work funky because of threads. we register ourselves as the
  52                 // observer and then pass up the messages that are actually from this object (as we can't only observe self due to threads)
  53                 // to our delegate, and not to all delegates
  54                 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sendMessageToDelegate:) name:nil object:nil];
  55         }
  56         return self;
  57 }
  58
  59 /**
  60  * Close our socket and clean up anything else
  61  */
  62 - (void)close
  63 {
  64         [[NSNotificationCenter defaultCenter] removeObserver:self];
  65         close(sock);
  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)aDelegate
  80 {
  81         delegate = aDelegate;
  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(sock, (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         // create an INET socket that we'll be listen()ing on
 151         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
 152
 153         // create our address given the port
 154         struct sockaddr_in address;
 155         address.sin_family = AF_INET;
 156         address.sin_port = htons(port);
 157         address.sin_addr.s_addr = htonl(INADDR_ANY);
 158         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 159
 160         // allow an already-opened socket to be reused
 161         int yes = 1;
 162         setsockopt(socketOpen, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
 163
 164         // bind the socket... and don't give up until we've tried for a while
 165         int tries = 0;
 166         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 167         {
 168                 if (tries >= 5)
 169                 {
 170                         close(socketOpen);
 171                         [self postNotification:NsockError withObject:@"Could not bind to socket"];
 172                         return;
 173                 }
 174                 NSLog(@"couldn't bind to the socket... trying again in 5");
 175                 sleep(5);
 176                 tries++;
 177         }
 178
 179         // now we just have to keep our ears open
 180         if (listen(socketOpen, 0) == -1)
 181         {
 182                 [self postNotification:NsockError withObject:@"Could not use bound socket for listening"];
 183         }
 184
 185         // accept a connection
 186         struct sockaddr_in remoteAddress;
 187         socklen_t remoteAddressLen = sizeof(remoteAddress);
 188         sock = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 189         if (sock < 0)
 190         {
 191                 close(socketOpen);
 192                 [self postNotification:NsockError withObject:@"Client failed to accept remote socket"];
 193                 return;
 194         }
 195
 196         // we're done listening now that we have a connection
 197         close(socketOpen);
 198
 199         [self postNotification:NsockDidAccept withObject:nil];
 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(sock, &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         memset(packetLength, '\0', sizeof(packetLength));
 224         int i = 0;
 225         while (buffer[i] != '\0')
 226         {
 227                 packetLength[i] = buffer[i];
 228                 i++;
 229         }
 230
 231         // we also want the null byte, so move us up 1
 232         i++;
 233
 234         // the total length of the full transmission
 235         int length = atoi(packetLength);
 236
 237         // move the packet part of the received data into it's own char[]
 238         char packet[sizeof(buffer)];
 239         memset(packet, '\0', sizeof(packet));
 240         memmove(packet, &buffer[i], recvd - i);
 241
 242         // convert bytes to NSData
 243         [data appendBytes:packet length:recvd - i];
 244
 245         // check if we have a partial packet
 246         if (length + i > sizeof(buffer))
 247         {
 248                 while (recvd < length)
 249                 {
 250                         int latest = recv(sock, &buffer, sizeof(buffer), 0);
 251                         if (latest < 1)
 252                         {
 253                                 [self postNotification:NsockError withObject:@"Socket closed or could not be read"];
 254                                 return;
 255                         }
 256                         [data appendBytes:buffer length:latest];
 257                         recvd += latest;
 258                 }
 259         }
 260
 261         //NSLog(@"data = %@", [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease]);
 262
 263         if (selector != nil)
 264         {
 265                 [self postNotification:NsockDataReceived
 266                                          withObject:data
 267                                            withDict:[NSMutableDictionary dictionaryWithObject:NSStringFromSelector(selector) forKey:sockNotificationReceiver]];
 268         }
 269         else
 270         {
 271                 [self postNotification:NsockDataReceived withObject:data];
 272         }
 273 }
 274
 275 /**
 276  * Sends a given NSString over the socket
 277  */
 278 - (void)send:(NSString *)data
 279 {
 280         data = [NSString stringWithFormat:@"%@\0", data];
 281         int sent = send(sock, [data UTF8String], [data length], 0);
 282         if (sent < 0)
 283         {
 284                 [self postNotification:NsockError withObject:@"Failed to write data to socket"];
 285                 return;
 286         }
 287         if (sent < [data length])
 288         {
 289                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 290                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 291         }
 292
 293         [self postNotification:NsockDataSent withObject:[data substringToIndex:sent]];
 294 }
 295
 296 /**
 297  * Helper method to simply post a notification to the default notification center with a given name and object
 298  */
 299 - (void)postNotification:(NSString *)name withObject:(id)obj
 300 {
 301         [self postNotification:name withObject:obj withDict:[NSMutableDictionary dictionary]];
 302 }
 303
 304 /**
 305  * Another helper method to aid in the posting of notifications. This one should be used if you have additional
 306  * things for the userInfo. This automatically adds the sockNotificationDebuggerConnection key.
 307  */
 308 - (void)postNotification:(NSString *)name withObject:(id)obj withDict:(NSMutableDictionary *)dict
 309 {
 310         [dict setValue:delegate forKey:sockNotificationDebuggerConnection];
 311         [[NSNotificationCenter defaultCenter] postNotificationName:name object:obj userInfo:dict];
 312 }
 313
 314 @end