Source/SocketWrapper.m

   1 /*
   2  * MacGDBp
   3  * Copyright (c) 2007 - 2009, 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 ()
  25 @property (copy, readwrite, getter=remoteHost) NSString *hostname;
  26
  27 - (void)error:(NSString *)msg;
  28 @end
  29
  30 @implementation SocketWrapper
  31 @synthesize hostname;
  32
  33 /**
  34  * Initializes the socket wrapper with a host and port
  35  */
  36 - (id)initWithConnection:(GDBpConnection *)cnx
  37 {
  38         if (self = [super init])
  39         {
  40                 connection = [cnx retain];
  41                 port = [connection port];
  42         }
  43         return self;
  44 }
  45
  46 /**
  47  * Dealloc
  48  */
  49 - (void)dealloc
  50 {
  51         [connection release];
  52         [hostname release];
  53         [super dealloc];
  54 }
  55
  56 /**
  57  * Close our socket and clean up anything else
  58  */
  59 - (void)close
  60 {
  61         close(sock);
  62 }
  63
  64 /**
  65  * Returns the delegate
  66  */
  67 - (id)delegate
  68 {
  69         return delegate;
  70 }
  71
  72 /**
  73  * Sets the delegate but does *not* retain it
  74  */
  75 - (void)setDelegate:(id)aDelegate
  76 {
  77         delegate = aDelegate;
  78 }
  79
  80 /**
  81  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
  82  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
  83  */
  84 - (void)connect
  85 {
  86         [NSThread detachNewThreadSelector:@selector(connect:) toTarget:self withObject:nil];
  87 }
  88
  89 /**
  90  * This does the actual dirty work (in a separate thread) of connecting to a socket
  91  */
  92 - (void)connect:(id)obj
  93 {
  94         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
  95
  96         // create an INET socket that we'll be listen()ing on
  97         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
  98
  99         // create our address given the port
 100         struct sockaddr_in address;
 101         address.sin_family = AF_INET;
 102         address.sin_port = htons(port);
 103         address.sin_addr.s_addr = htonl(INADDR_ANY);
 104         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 105
 106         // allow an already-opened socket to be reused
 107         int yes = 1;
 108         setsockopt(socketOpen, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
 109
 110         // bind the socket... and don't give up until we've tried for a while
 111         int tries = 0;
 112         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 113         {
 114                 if (tries >= 5)
 115                 {
 116                         close(socketOpen);
 117                         [self error:@"Could not bind to socket"];
 118                         [pool release];
 119                         return;
 120                 }
 121                 NSLog(@"couldn't bind to the socket... trying again in 5");
 122                 sleep(5);
 123                 tries++;
 124         }
 125
 126         // now we just have to keep our ears open
 127         if (listen(socketOpen, 0) == -1)
 128         {
 129                 [self error:@"Could not use bound socket for listening"];
 130         }
 131
 132         // accept a connection
 133         struct sockaddr_in remoteAddress;
 134         socklen_t remoteAddressLen = sizeof(remoteAddress);
 135         sock = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 136         if (sock < 0)
 137         {
 138                 close(socketOpen);
 139                 [self error:@"Client failed to accept remote socket"];
 140                 [pool release];
 141                 return;
 142         }
 143
 144         // we're done listening now that we have a connection
 145         close(socketOpen);
 146
 147         struct sockaddr_in addr;
 148         socklen_t addrLength;
 149         if (getpeername(sock, (struct sockaddr *)&addr, &addrLength) < 0)
 150         {
 151                 [self error:@"Could not get remote hostname."];
 152         }
 153         char *name = inet_ntoa(addr.sin_addr);
 154         [self setHostname:[NSString stringWithUTF8String:name]];
 155
 156         [connection performSelectorOnMainThread:@selector(socketDidAccept:) withObject:nil waitUntilDone:NO];
 157
 158         [pool release];
 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 stringWithCString:packet length:recvd - i]];
 201
 202         // check if we have a partial packet
 203         if (length + i > sizeof(buffer))
 204         {
 205                 while (recvd < length + i)
 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 stringWithCString:buffer length:latest]];
 214                         recvd += latest;
 215                 }
 216         }
 217
 218         NSString *tmp = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // strip whitespace
 219         tmp = [tmp substringToIndex:[tmp length] - 1]; // don't want the null byte
 220
 221         NSAssert([tmp UTF8String][[tmp length] - 1] == '>', @"-[SocketWrapper receive] buffer is incomplete");
 222
 223         return tmp;
 224 }
 225
 226 /**
 227  * Sends a given NSString over the socket. Returns YES on complete submission.
 228  */
 229 - (BOOL)send:(NSString *)data
 230 {
 231         data = [NSString stringWithFormat:@"%@\0", data];
 232         int sent = send(sock, [data UTF8String], [data length], 0);
 233         if (sent < 0)
 234         {
 235                 [self error:@"Failed to write data to socket"];
 236                 return NO;
 237         }
 238         if (sent < [data length])
 239         {
 240                 // TODO - do we really need to worry about partial sends with the lenght of our commands?
 241                 NSLog(@"FAIL: only partial packet was sent; sent %d bytes", sent);
 242                 return NO;
 243         }
 244
 245         return YES;
 246 }
 247
 248 /**
 249  * Helper method that just calls -[DebuggerWindowController setError:] on the main thread
 250  */
 251 - (void)error:(NSString *)msg
 252 {
 253         [delegate performSelectorOnMainThread:@selector(setError:) withObject:msg waitUntilDone:NO];
 254 }
 255
 256 @end