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         return hostname;
  75 }
  76
  77 /**
  78  * Connects to a socket on the port specified during init. This will dispatch another thread to do the
  79  * actual waiting. Delegate notifications are posted along the way to let the client know what is going on.
  80  */
  81 - (void)connect
  82 {
  83         [NSThread detachNewThreadSelector:@selector(connect:) toTarget:self withObject:nil];
  84 }
  85
  86 /**
  87  * This does the actual dirty work (in a separate thread) of connecting to a socket
  88  */
  89 - (void)connect:(id)obj
  90 {
  91         // create an INET socket that we'll be listen()ing on
  92         int socketOpen = socket(PF_INET, SOCK_STREAM, 0);
  93
  94         // create our address given the port
  95         struct sockaddr_in address;
  96         address.sin_family = AF_INET;
  97         address.sin_port = htons(port);
  98         address.sin_addr.s_addr = htonl(INADDR_ANY);
  99         memset(address.sin_zero, '\0', sizeof(address.sin_zero));
 100
 101         // allow an already-opened socket to be reused
 102         int yes = 1;
 103         setsockopt(socketOpen, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
 104
 105         // bind the socket... and don't give up until we've tried for a while
 106         int tries = 0;
 107         while (bind(socketOpen, (struct sockaddr *)&address, sizeof(address)) < 0)
 108         {
 109                 if (tries >= 5)
 110                 {
 111                         close(socketOpen);
 112                         [self error:@"Could not bind to socket"];
 113                         return;
 114                 }
 115                 NSLog(@"couldn't bind to the socket... trying again in 5");
 116                 sleep(5);
 117                 tries++;
 118         }
 119
 120         // now we just have to keep our ears open
 121         if (listen(socketOpen, 0) == -1)
 122         {
 123                 [self error:@"Could not use bound socket for listening"];
 124         }
 125
 126         // accept a connection
 127         struct sockaddr_in remoteAddress;
 128         socklen_t remoteAddressLen = sizeof(remoteAddress);
 129         sock = accept(socketOpen, (struct sockaddr *)&remoteAddress, &remoteAddressLen);
 130         if (sock < 0)
 131         {
 132                 close(socketOpen);
 133                 [self error:@"Client failed to accept remote socket"];
 134                 return;
 135         }
 136
 137         // we're done listening now that we have a connection
 138         close(socketOpen);
 139
 140         struct sockaddr_in addr;
 141         socklen_t addrLength;
 142         if (getpeername(sock, (struct sockaddr *)&addr, &addrLength) < 0)
 143         {
 144                 [self error:@"Could not get remote hostname."];
 145         }
 146         char *name = inet_ntoa(addr.sin_addr);
 147         hostname = [NSString stringWithUTF8String:name];
 148
 149         [connection performSelectorOnMainThread:@selector(socketDidAccept:) withObject:nil waitUntilDone:NO];
 150 }
 151
 152 /**
 153  * Reads from the socket and returns the result as a NSString (because it's always going to be XML). Be aware
 154  * that the underlying socket recv() call will *wait* for the server to send a message, so be sure that this
 155  * is used either in a threaded environment so the interface does not hang, or when you *know* the server
 156  * will return something (which we almost always do). Returns the data that was received from the socket.
 157  */
 158 - (NSString *)receive
 159 {
 160         // create a buffer
 161         char buffer[1024];
 162
 163         // do our initial recv() call to get (hopefully) all the data and the lengh of the packet
 164         int recvd = recv(sock, &buffer, sizeof(buffer), 0);
 165
 166         // take the received data and put it into an NSData
 167         NSMutableString *str = [NSMutableString string];
 168
 169         // strip the length from the packet, and clear the null byte then add it to the NSData
 170         char packetLength[8];
 171         memset(packetLength, '\0', sizeof(packetLength));
 172         int i = 0;
 173         while (buffer[i] != '\0')
 174         {
 175                 packetLength[i] = buffer[i];
 176                 i++;
 177         }
 178
 179         // we also want the null byte, so move us up 1
 180         i++;
 181
 182         // the total length of the full transmission
 183         int length = atoi(packetLength);
 184
 185         // move the packet part of the received data into it's own char[]
 186         char packet[sizeof(buffer)];
 187         memset(packet, '\0', sizeof(packet));
 188         memmove(packet, &buffer[i], recvd - i);
 189
 190         // convert bytes to NSString
 191         [str appendString:[[NSString alloc] initWithCString:packet length:recvd - i]];
 192
 193         // check if we have a partial packet
 194         if (length + i > sizeof(buffer))
 195         {
 196                 while (recvd < length)
 197                 {
 198                         int latest = recv(sock, &buffer, sizeof(buffer), 0);
 199                         if (latest < 1)
 200                         {
 201                                 [self error:@"Socket closed or could not be read"];
 202                                 return nil;
 203                         }
 204                         [str appendString:[[NSString alloc] initWithCString:buffer length:latest]];
 205                         recvd += latest;
 206                 }
 207         }
 208
 209         NSString *tmp = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // strip whitespace
 210         return [tmp substringToIndex:[tmp length] - 1]; // don't want the null byte
 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