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         // create an INET socket that we'll be listen()ing on
 101         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
 102
 103         // create our address given the port
 104         struct sockaddr_in address;
 105         address.sin_family = AF_INET;
 106         address.sin_port = htons(port);
 107         address.sin_addr.s_addr = htonl(INADDR_ANY);
 108         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 109
 110         // allow an already-opened socket to be reused
 111         int yes = 1;
 112         setsockopt(socketOpen, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
 113
 114         // bind the socket... and don't give up until we've tried for a while
 115         int tries = 0;
 116         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 117         {
 118                 if (tries >= 5)
 119                 {
 120                         close(socketOpen);
 121                         [self error:@"Could not bind to socket"];
 122                         return;
 123                 }
 124                 NSLog(@"couldn't bind to the socket... trying again in 5");
 125                 sleep(5);
 126                 tries++;
 127         }
 128
 129         // now we just have to keep our ears open
 130         if (listen(socketOpen, 0) == -1)
 131         {
 132                 [self error:@"Could not use bound socket for listening"];
 133         }
 134
 135         // accept a connection
 136         struct sockaddr_in remoteAddress;
 137         socklen_t remoteAddressLen = sizeof(remoteAddress);
 138         sock = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 139         if (sock < 0)
 140         {
 141                 close(socketOpen);
 142                 [self error:@"Client failed to accept remote socket"];
 143                 return;
 144         }
 145
 146         // we're done listening now that we have a connection
 147         close(socketOpen);
 148
 149         struct sockaddr_in addr;
 150         socklen_t addrLength;
 151         if (getpeername(sock, (struct sockaddr *)&addr, &addrLength) < 0)
 152         {
 153                 [self error:@"Could not get remote hostname."];
 154         }
 155         char *name = inet_ntoa(addr.sin_addr);
 156         hostname = [NSString stringWithUTF8String:name];
 157
 158         [connection performSelectorOnMainThread:@selector(socketDidAccept:) withObject:nil waitUntilDone:NO];
 159 }
 160
 161 /**
 162  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 163  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 164  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 165  * will return something (which we almost always do). Returns the data that was received from the socket.
 166  */
 167 - (NSString *)receive
 168 {
 169         // create a buffer
 170         char buffer[1024];
 171
 172         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 173         int recvd = recv(sock, &buffer, sizeof(buffer), 0);
 174
 175         // take the received data and put it into an NSData
 176         NSMutableString *str = [NSMutableString string];
 177
 178         // strip the length from the packet, and clear the null byte then add it to the NSData
 179         char packetLength[8];
 180         memset(packetLength, '\0', sizeof(packetLength));
 181         int i = 0;
 182         while (buffer[i] != '\0')
 183         {
 184                 packetLength[i] = buffer[i];
 185                 i++;
 186         }
 187
 188         // we also want the null byte, so move us up 1
 189         i++;
 190
 191         // the total length of the full transmission
 192         int length = atoi(packetLength);
 193
 194         // move the packet part of the received data into it's own char[]
 195         char packet[sizeof(buffer)];
 196         memset(packet, '\0', sizeof(packet));
 197         memmove(packet, &buffer[i], recvd - i);
 198
 199         // convert bytes to NSString
 200         [str appendString:[[NSString alloc] initWithCString:packet length:recvd - i]];
 201
 202         // check if we have a partial packet
 203         if (length + i > sizeof(buffer))
 204         {
 205                 while (recvd < length)
 206                 {
 207                         int latest = recv(sock, &buffer, sizeof(buffer), 0);
 208                         if (latest < 1)
 209                         {
 210                                 [self error:@"Socket closed or could not be read"];
 211                                 return nil;
 212                         }
 213                         [str appendString:[[NSString alloc] initWithCString:buffer length:latest]];
 214                         recvd += latest;
 215                 }
 216         }
 217
 218         NSString *tmp = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // strip whitespace
 219         return [tmp substringToIndex:[tmp length] - 1]; // don't want the null byte
 220 }
 221
 222 /**
 223  * Sends a given NSString over the socket. Returns YES on complete submission.
 224  */
 225 - (BOOL)send:(NSString *)data
 226 {
 227         data = [NSString stringWithFormat:@"%@\0", data];
 228         int sent = send(sock, [data UTF8String], [data length], 0);
 229         if (sent < 0)
 230         {
 231                 [self error:@"Failed to write data to socket"];
 232                 return NO;
 233         }
 234         if (sent < [data length])
 235         {
 236                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 237                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 238                 return NO;
 239         }
 240
 241         return YES;
 242 }
 243
 244 /**
 245  * Helper method that just calls -[DebuggerWindowController setError:] on the main thread
 246  */
 247 - (void)error:(NSString *)msg
 248 {
 249         [delegate performSelectorOnMainThread:@selector(errorEncountered:) withObject:msg waitUntilDone:NO];
 250 }
 251
 252 @end