Source/SocketWrapper.m

   1 /*
   2  * MacGDBp
   3  * Copyright (c) 2007 - 2008, 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 @interface SocketWrapper (Private)
  25
  26 - (void)error:(NSString *)msg;
  27
  28 @end
  29
  30 @implementation SocketWrapper
  31
  32 /**
  33  * Initializes the socket wrapper with a host and port
  34  */
  35 - (id)initWithConnection:(DebuggerConnection *)cnx
  36 {
  37         if (self = [super init])
  38         {
  39                 connection = [cnx retain];
  40                 port = [connection port];
  41         }
  42         return self;
  43 }
  44
  45 /**
  46  * Dealloc
  47  */
  48 - (void)dealloc
  49 {
  50         [connection release];
  51         [super dealloc];
  52 }
  53
  54 /**
  55  * Close our socket and clean up anything else
  56  */
  57 - (void)close
  58 {
  59         close(sock);
  60 }
  61
  62 /**
  63  * Returns the delegate
  64  */
  65 - (id)delegate
  66 {
  67         return delegate;
  68 }
  69
  70 /**
  71  * Sets the delegate but does *not* retain it
  72  */
  73 - (void)setDelegate:(id)aDelegate
  74 {
  75         delegate = aDelegate;
  76 }
  77
  78 /**
  79  * Returns the name of the host to whom we are currently connected.
  80  */
  81 - (NSString *)remoteHost
  82 {
  83         return hostname;
  84 }
  85
  86 /**
  87  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
  88  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
  89  */
  90 - (void)connect
  91 {
  92         [NSThread detachNewThreadSelector:@selector(connect:) toTarget:self withObject:nil];
  93 }
  94
  95 /**
  96  * This does the actual dirty work (in a separate thread) of connecting to a socket
  97  */
  98 - (void)connect:(id)obj
  99 {
 100         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 101
 102         // create an INET socket that we'll be listen()ing on
 103         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
 104
 105         // create our address given the port
 106         struct sockaddr_in address;
 107         address.sin_family = AF_INET;
 108         address.sin_port = htons(port);
 109         address.sin_addr.s_addr = htonl(INADDR_ANY);
 110         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 111
 112         // allow an already-opened socket to be reused
 113         int yes = 1;
 114         setsockopt(socketOpen, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
 115
 116         // bind the socket... and don't give up until we've tried for a while
 117         int tries = 0;
 118         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 119         {
 120                 if (tries >= 5)
 121                 {
 122                         close(socketOpen);
 123                         [self error:@"Could not bind to socket"];
 124                         [pool release];
 125                         return;
 126                 }
 127                 NSLog(@"couldn't bind to the socket... trying again in 5");
 128                 sleep(5);
 129                 tries++;
 130         }
 131
 132         // now we just have to keep our ears open
 133         if (listen(socketOpen, 0) == -1)
 134         {
 135                 [self error:@"Could not use bound socket for listening"];
 136         }
 137
 138         // accept a connection
 139         struct sockaddr_in remoteAddress;
 140         socklen_t remoteAddressLen = sizeof(remoteAddress);
 141         sock = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 142         if (sock < 0)
 143         {
 144                 close(socketOpen);
 145                 [self error:@"Client failed to accept remote socket"];
 146                 [pool release];
 147                 return;
 148         }
 149
 150         // we're done listening now that we have a connection
 151         close(socketOpen);
 152
 153         struct sockaddr_in addr;
 154         socklen_t addrLength;
 155         if (getpeername(sock, (struct sockaddr *)&addr, &addrLength) < 0)
 156         {
 157                 [self error:@"Could not get remote hostname."];
 158         }
 159         char *name = inet_ntoa(addr.sin_addr);
 160         hostname = [NSString stringWithUTF8String:name];
 161
 162         [connection performSelectorOnMainThread:@selector(socketDidAccept:) withObject:nil waitUntilDone:NO];
 163
 164         [pool release];
 165 }
 166
 167 /**
 168  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 169  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 170  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 171  * will return something (which we almost always do). Returns the data that was received from the socket.
 172  */
 173 - (NSString *)receive
 174 {
 175         // create a buffer
 176         char buffer[1024];
 177
 178         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 179         int recvd = recv(sock, &buffer, sizeof(buffer), 0);
 180
 181         // take the received data and put it into an NSData
 182         NSMutableString *str = [NSMutableString string];
 183
 184         // strip the length from the packet, and clear the null byte then add it to the NSData
 185         char packetLength[8];
 186         memset(packetLength, '\0', sizeof(packetLength));
 187         int i = 0;
 188         while (buffer[i] != '\0')
 189         {
 190                 packetLength[i] = buffer[i];
 191                 i++;
 192         }
 193
 194         // we also want the null byte, so move us up 1
 195         i++;
 196
 197         // the total length of the full transmission
 198         int length = atoi(packetLength);
 199
 200         // move the packet part of the received data into it's own char[]
 201         char packet[sizeof(buffer)];
 202         memset(packet, '\0', sizeof(packet));
 203         memmove(packet, &buffer[i], recvd - i);
 204
 205         // convert bytes to NSString
 206         [str appendString:[[NSString alloc] initWithCString:packet length:recvd - i]];
 207
 208         // check if we have a partial packet
 209         if (length + i > sizeof(buffer))
 210         {
 211                 while (recvd < length)
 212                 {
 213                         int latest = recv(sock, &buffer, sizeof(buffer), 0);
 214                         if (latest < 1)
 215                         {
 216                                 [self error:@"Socket closed or could not be read"];
 217                                 return nil;
 218                         }
 219                         [str appendString:[[NSString alloc] initWithCString:buffer length:latest]];
 220                         recvd += latest;
 221                 }
 222         }
 223
 224         NSString *tmp = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // strip whitespace
 225         return [tmp substringToIndex:[tmp length] - 1]; // don't want the null byte
 226 }
 227
 228 /**
 229  * Sends a given NSString over the socket. Returns YES on complete submission.
 230  */
 231 - (BOOL)send:(NSString *)data
 232 {
 233         data = [NSString stringWithFormat:@"%@\0", data];
 234         int sent = send(sock, [data UTF8String], [data length], 0);
 235         if (sent < 0)
 236         {
 237                 [self error:@"Failed to write data to socket"];
 238                 return NO;
 239         }
 240         if (sent < [data length])
 241         {
 242                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 243                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 244                 return NO;
 245         }
 246
 247         return YES;
 248 }
 249
 250 /**
 251  * Helper method that just calls -[DebuggerWindowController setError:] on the main thread
 252  */
 253 - (void)error:(NSString *)msg
 254 {
 255         [delegate performSelectorOnMainThread:@selector(errorEncountered:) withObject:msg waitUntilDone:NO];
 256 }
 257
 258 @end