apps/irssi/src/core/net-nonblock.c

   1 /*
   2  net-nonblock.c : Nonblocking net_connect()
   3
   4     Copyright (C) 1998-2000 Timo Sirainen
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 */
  20
  21 #include "module.h"
  22
  23 #include <signal.h>
  24
  25 #include "pidwait.h"
  26 #include "net-nonblock.h"
  27
  28 typedef struct {
  29         NET_CALLBACK func;
  30         void *data;
  31
  32         GIOChannel *pipes[2];
  33         int port;
  34         IPADDR *my_ip;
  35         int tag;
  36 } SIMPLE_THREAD_REC;
  37
  38 #define is_fatal_error(err) \
  39         (err != 0 && err != G_IO_ERROR_AGAIN && errno != EINTR)
  40
  41 static int g_io_channel_write_block(GIOChannel *channel, void *data, int len)
  42 {
  43         unsigned int ret;
  44         int err, sent;
  45
  46         sent = 0;
  47         do {
  48                 err = g_io_channel_write(channel, (char *) data + sent,
  49                                          len-sent, &ret);
  50                 sent += ret;
  51         } while (sent < len && !is_fatal_error(err));
  52
  53         return err != 0 ? -1 : 0;
  54 }
  55
  56 static int g_io_channel_read_block(GIOChannel *channel, void *data, int len)
  57 {
  58         time_t maxwait;
  59         unsigned int ret;
  60         int err, received;
  61
  62         maxwait = time(NULL)+2;
  63         received = 0;
  64         do {
  65                 err = g_io_channel_read(channel, (char *) data + received,
  66                                         len-received, &ret);
  67                 received += ret;
  68         } while (received < len && time(NULL) < maxwait &&
  69                  (ret != 0 || !is_fatal_error(err)));
  70
  71         return received < len ? -1 : 0;
  72 }
  73
  74 /* nonblocking gethostbyname(), ip (IPADDR) + error (int, 0 = not error) is
  75    written to pipe when found PID of the resolver child is returned */
  76 int net_gethostbyname_nonblock(const char *addr, GIOChannel *pipe,
  77                                int reverse_lookup)
  78 {
  79         RESOLVED_IP_REC rec;
  80         const char *errorstr;
  81 #ifndef WIN32
  82         int pid;
  83 #endif
  84         int len;
  85
  86         g_return_val_if_fail(addr != NULL, FALSE);
  87
  88 #ifndef WIN32
  89         pid = fork();
  90         if (pid > 0) {
  91                 /* parent */
  92                 pidwait_add(pid);
  93                 return pid;
  94         }
  95
  96         if (pid != 0) {
  97                 /* failed! */
  98                 g_warning("net_connect_thread(): fork() failed! "
  99                           "Using blocking resolving");
 100         }
 101 #endif
 102
 103         /* child */
 104         memset(&rec, 0, sizeof(rec));
 105         rec.error = net_gethostbyname(addr, &rec.ip4, &rec.ip6);
 106         if (rec.error == 0) {
 107                 errorstr = NULL;
 108                 if (reverse_lookup) {
 109                         /* reverse lookup the IP, ignore any error */
 110                         if (rec.ip4.family != 0)
 111                                 net_gethostbyaddr(&rec.ip4, &rec.host4);
 112                         if (rec.ip6.family != 0)
 113                                 net_gethostbyaddr(&rec.ip6, &rec.host6);
 114                 }
 115         } else {
 116                 errorstr = net_gethosterror(rec.error);
 117                 rec.errlen = errorstr == NULL ? 0 : strlen(errorstr)+1;
 118         }
 119
 120         g_io_channel_write_block(pipe, &rec, sizeof(rec));
 121         if (rec.errlen != 0)
 122                 g_io_channel_write_block(pipe, (void *) errorstr, rec.errlen);
 123         else {
 124                 if (rec.host4) {
 125                         len = strlen(rec.host4) + 1;
 126                         g_io_channel_write_block(pipe, (void *) &len,
 127                                                        sizeof(int));
 128                         g_io_channel_write_block(pipe, (void *) rec.host4,
 129                                                        len);
 130                 }
 131                 if (rec.host6) {
 132                         len = strlen(rec.host6) + 1;
 133                         g_io_channel_write_block(pipe, (void *) &len,
 134                                                        sizeof(int));
 135                         g_io_channel_write_block(pipe, (void *) rec.host6,
 136                                                        len);
 137                 }
 138         }
 139
 140 #ifndef WIN32
 141         if (pid == 0)
 142                 _exit(99);
 143 #endif
 144
 145         /* we used blocking lookup */
 146         return 0;
 147 }
 148
 149 /* get the resolved IP address */
 150 int net_gethostbyname_return(GIOChannel *pipe, RESOLVED_IP_REC *rec)
 151 {
 152         int len;
 153
 154         rec->error = -1;
 155         rec->errorstr = NULL;
 156         rec->host4 = NULL;
 157         rec->host6 = NULL;
 158
 159 #ifndef WIN32
 160         fcntl(g_io_channel_unix_get_fd(pipe), F_SETFL, O_NONBLOCK);
 161 #endif
 162
 163         /* get ip+error */
 164         if (g_io_channel_read_block(pipe, rec, sizeof(*rec)) == -1) {
 165                 rec->errorstr = g_strdup_printf("Host name lookup: %s",
 166                                                 g_strerror(errno));
 167                 return -1;
 168         }
 169
 170         if (rec->error) {
 171                 /* read error string, if we can't read everything for some
 172                    reason, just ignore it. */
 173                 rec->errorstr = g_malloc0(rec->errlen+1);
 174                 g_io_channel_read_block(pipe, rec->errorstr, rec->errlen);
 175         } else {
 176                 if (rec->host4) {
 177                         g_io_channel_read_block(pipe, &len, sizeof(int));
 178                         rec->host4 = g_malloc0(len);
 179                         g_io_channel_read_block(pipe, rec->host4, len);
 180                 }
 181                 if (rec->host6) {
 182                         g_io_channel_read_block(pipe, &len, sizeof(int));
 183                         rec->host6 = g_malloc0(len);
 184                         g_io_channel_read_block(pipe, rec->host6, len);
 185                 }
 186         }
 187
 188         return 0;
 189 }
 190
 191 /* Get host name, call func when finished */
 192 int net_gethostbyaddr_nonblock(IPADDR *ip, NET_HOST_CALLBACK func, void *data)
 193 {
 194         /* FIXME: not implemented */
 195         return FALSE;
 196 }
 197
 198 /* Kill the resolver child */
 199 void net_disconnect_nonblock(int pid)
 200 {
 201         g_return_if_fail(pid > 0);
 202
 203 #ifndef WIN32
 204         kill(pid, SIGKILL);
 205 #endif
 206 }
 207
 208 static void simple_init(SIMPLE_THREAD_REC *rec, GIOChannel *handle)
 209 {
 210         g_return_if_fail(rec != NULL);
 211
 212         g_source_remove(rec->tag);
 213
 214         if (net_geterror(handle) != 0) {
 215                 /* failed */
 216                 g_io_channel_close(handle);
 217                 g_io_channel_unref(handle);
 218                 handle = NULL;
 219         }
 220
 221         rec->func(handle, rec->data);
 222         g_free(rec);
 223 }
 224
 225 static void simple_readpipe(SIMPLE_THREAD_REC *rec, GIOChannel *pipe)
 226 {
 227         RESOLVED_IP_REC iprec;
 228         GIOChannel *handle;
 229         IPADDR *ip;
 230
 231         g_return_if_fail(rec != NULL);
 232
 233         g_source_remove(rec->tag);
 234
 235         net_gethostbyname_return(pipe, &iprec);
 236         g_free_not_null(iprec.errorstr);
 237
 238         g_io_channel_close(rec->pipes[0]);
 239         g_io_channel_unref(rec->pipes[0]);
 240         g_io_channel_close(rec->pipes[1]);
 241         g_io_channel_unref(rec->pipes[1]);
 242
 243         ip = iprec.ip4.family != 0 ? &iprec.ip4 : &iprec.ip6;
 244         handle = iprec.error == -1 ? NULL :
 245                 net_connect_ip(ip, rec->port, rec->my_ip);
 246
 247         g_free_not_null(rec->my_ip);
 248
 249         if (handle == NULL) {
 250                 /* failed */
 251                 rec->func(NULL, rec->data);
 252                 g_free(rec);
 253                 return;
 254         }
 255
 256         rec->tag = g_input_add(handle, G_INPUT_READ | G_INPUT_WRITE,
 257                                (GInputFunction) simple_init, rec);
 258 }
 259
 260 /* Connect to server, call func when finished */
 261 int net_connect_nonblock(const char *server, int port, const IPADDR *my_ip,
 262                          NET_CALLBACK func, void *data)
 263 {
 264         SIMPLE_THREAD_REC *rec;
 265         int fd[2];
 266
 267         g_return_val_if_fail(server != NULL, FALSE);
 268         g_return_val_if_fail(func != NULL, FALSE);
 269
 270         if (pipe(fd) != 0) {
 271                 g_warning("net_connect_nonblock(): pipe() failed.");
 272                 return FALSE;
 273         }
 274
 275         rec = g_new0(SIMPLE_THREAD_REC, 1);
 276         rec->port = port;
 277         if (my_ip != NULL) {
 278                 rec->my_ip = g_malloc(sizeof(IPADDR));
 279                 memcpy(rec->my_ip, my_ip, sizeof(IPADDR));
 280         }
 281         rec->func = func;
 282         rec->data = data;
 283         rec->pipes[0] = g_io_channel_unix_new(fd[0]);
 284         rec->pipes[1] = g_io_channel_unix_new(fd[1]);
 285
 286         /* start nonblocking host name lookup */
 287         net_gethostbyname_nonblock(server, rec->pipes[1], 0);
 288         rec->tag = g_input_add(rec->pipes[0], G_INPUT_READ,
 289                                (GInputFunction) simple_readpipe, rec);
 290
 291         return TRUE;
 292 }