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 *SocketWrapperNotificationConnection = @"debuggerconnection";
  25 NSString *SocketDidAcceptNotification = @"socketdidaccept";
  26
  27 @implementation SocketWrapper
  28
  29 /**
  30  * Initializes the socket wrapper with a host and port
  31  */
  32 - (id)initWithPort: (int)port
  33 {
  34         if (self = [super init])
  35         {
  36                 _port = port;
  37         }
  38         return self;
  39 }
  40
  41 /**
  42  * Close our socket and clean up anything else
  43  */
  44 - (void)dealloc
  45 {
  46         close(_socket);
  47
  48         [super dealloc];
  49 }
  50
  51 /**
  52  * Returns the delegate
  53  */
  54 - (id)delegate
  55 {
  56         return _delegate;
  57 }
  58
  59 /**
  60  * Sets the delegate but does *not* retain it
  61  */
  62 - (void)setDelegate: (id)delegate
  63 {
  64         if (_delegate != nil)
  65         {
  66                 [[NSNotificationCenter defaultCenter] removeObserver: _delegate];
  67         }
  68
  69         _delegate = delegate;
  70
  71         [[NSNotificationCenter defaultCenter] addObserver: _delegate selector: @selector(socketDidAccept:) name: SocketDidAcceptNotification object: nil];
  72 }
  73
  74 /**
  75  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
  76  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
  77  */
  78 - (void)connect
  79 {
  80         [NSThread detachNewThreadSelector: @selector(_connect:) toTarget: self withObject: nil];
  81 }
  82
  83 /**
  84  * This does the actual dirty work (in a separate thread) of connecting to a socket
  85  */
  86 - (void)_connect: (id)obj
  87 {
  88         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  89
  90         // create an INET socket that we'll be listen()ing on
  91         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
  92
  93         // create our address given the port
  94         struct sockaddr_in address;
  95         address.sin_family = AF_INET;
  96         address.sin_port = htons(_port);
  97         address.sin_addr.s_addr = htonl(INADDR_ANY);
  98         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
  99
 100         // bind the socket... and don't give up until we've tried for a while
 101         int tries = 0;
 102         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 103         {
 104                 if (tries >= 5)
 105                 {
 106                         close(socketOpen);
 107                         [_delegate errorEncountered: nil];
 108                 }
 109                 NSLog(@"couldn't bind to the socket... trying again in 5");
 110                 sleep(5);
 111                 tries++;
 112         }
 113
 114         // now we just have to keep our ears open
 115         if (listen(socketOpen, 0) == -1)
 116         {
 117                 [_delegate errorEncountered: nil];
 118         }
 119
 120         // accept a connection
 121         struct sockaddr_in remoteAddress;
 122         socklen_t remoteAddressLen = sizeof(remoteAddress);
 123         _socket = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 124         if (_socket < 0)
 125         {
 126                 close(socketOpen);
 127                 [_delegate errorEncountered: nil];
 128         }
 129
 130         // we're done listening now that we have a connection
 131         close(socketOpen);
 132
 133         [self _postNotification: SocketDidAcceptNotification withObject: nil];
 134
 135         [pool release];
 136 }
 137
 138 /**
 139  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 140  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 141  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 142  * will return something (which we almost always do).
 143  *
 144  * Data string returned is autorelease'd
 145  */
 146 - (void)receive
 147 {
 148         // create a buffer
 149         char buffer[1024];
 150
 151         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 152         int recvd = recv(_socket, &buffer, sizeof(buffer), 0);
 153
 154         // take the received data and put it into an NSData
 155         NSMutableData *data = [NSMutableData data];
 156
 157         // strip the length from the packet, and clear the null byte then add it to the NSData
 158         char packetLength[8];
 159         int i = 0;
 160         while (buffer[i] != '\0')
 161         {
 162                 packetLength[i] = buffer[i];
 163                 i++;
 164         }
 165
 166         // we also want the null byte, so move us up 1
 167         i++;
 168
 169         // the total length of the full transmission
 170         int length = atoi(packetLength);
 171
 172         // move the packet part of the received data into it's own char[]
 173         char packet[sizeof(buffer)];
 174         memmove(packet, &buffer[i], recvd - i);
 175
 176         // convert bytes to NSData
 177         [data appendBytes: packet length: recvd];
 178
 179         // check if we have a partial packet
 180         if (length + i > sizeof(buffer))
 181         {
 182                 while (recvd < length)
 183                 {
 184                         int latest = recv(_socket, &buffer, sizeof(buffer), 0);
 185                         if (latest < 1)
 186                         {
 187                                 NSLog(@"socket closed or error");
 188                         }
 189                         [data appendBytes: buffer length: latest];
 190                         recvd += latest;
 191                 }
 192         }
 193
 194         // convert the NSData into a NSString
 195         [_delegate dataReceived: [[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding] autorelease]];
 196 }
 197
 198 /**
 199  * Sends a given NSString over the socket
 200  */
 201 - (void)send: (NSString *)data
 202 {
 203         data = [NSString stringWithFormat: @"%@\0", data];
 204         int sent = send(_socket, [data UTF8String], [data length], 0);
 205         if (sent < 0)
 206         {
 207                 NSLog(@"error in sending");
 208         }
 209         if (sent < [data length])
 210         {
 211                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 212                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 213         }
 214
 215         [_delegate dataSent];
 216 }
 217
 218 /**
 219  * Helper method to simply post a notification to the default notification center with a given name and object
 220  */
 221 - (void)_postNotification: (NSString *)name withObject: (id)obj
 222 {
 223         NSDictionary *dict = [NSDictionary dictionaryWithObjects: [NSArray arrayWithObjects: _delegate, nil]
 224                                                                                                          forKeys: [NSArray arrayWithObjects: SocketWrapperNotificationConnection, nil]];
 225         [[NSNotificationCenter defaultCenter] postNotificationName: name object: obj userInfo: dict];
 226 }
 227
 228 @end