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