git.ozlabs.org Git - ccan/blob - ccan/nfs/socket.c

   1 /*
   2    Copyright (C) by Ronnie Sahlberg <ronniesahlberg@gmail.com> 2010
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <stdio.h>
  19 #include <unistd.h>
  20 #include <fcntl.h>
  21 #include <poll.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <time.h>
  25 #include <rpc/xdr.h>
  26 #include <arpa/inet.h>
  27 #include <sys/ioctl.h>
  28 #include "nfs.h"
  29 #include "libnfs-raw.h"
  30 #include "libnfs-private.h"
  31 #include "dlinklist.h"
  32
  33 static void set_nonblocking(int fd)
  34 {
  35         unsigned v;
  36         v = fcntl(fd, F_GETFL, 0);
  37         fcntl(fd, F_SETFL, v | O_NONBLOCK);
  38 }
  39
  40 int rpc_get_fd(struct rpc_context *rpc)
  41 {
  42         return rpc->fd;
  43 }
  44
  45 int rpc_which_events(struct rpc_context *rpc)
  46 {
  47         int events = POLLIN;
  48
  49         if (rpc->is_connected == 0) {
  50                 events |= POLLOUT;
  51         }
  52
  53         if (rpc->outqueue) {
  54                 events |= POLLOUT;
  55         }
  56         return events;
  57 }
  58
  59 static int rpc_write_to_socket(struct rpc_context *rpc)
  60 {
  61         ssize_t count;
  62
  63         if (rpc == NULL) {
  64                 printf("trying to write to socket for NULL context\n");
  65                 return -1;
  66         }
  67         if (rpc->fd == -1) {
  68                 printf("trying to write but not connected\n");
  69                 return -2;
  70         }
  71
  72         while (rpc->outqueue != NULL) {
  73                 ssize_t total;
  74
  75                 total = rpc->outqueue->outdata.size;
  76
  77                 count = write(rpc->fd, rpc->outqueue->outdata.data + rpc->outqueue->written, total - rpc->outqueue->written);
  78                 if (count == -1) {
  79                         if (errno == EAGAIN || errno == EWOULDBLOCK) {
  80                                 printf("socket would block, return from write to socket\n");
  81                                 return 0;
  82                         }
  83                         printf("Error when writing to socket :%s(%d)\n", strerror(errno), errno);
  84                         return -3;
  85                 }
  86
  87                 rpc->outqueue->written += count;
  88                 if (rpc->outqueue->written == total) {
  89                         struct rpc_pdu *pdu = rpc->outqueue;
  90
  91                         DLIST_REMOVE(rpc->outqueue, pdu);
  92                         DLIST_ADD_END(rpc->waitpdu, pdu, NULL);
  93                 }
  94         }
  95         return 0;
  96 }
  97
  98 static int rpc_read_from_socket(struct rpc_context *rpc)
  99 {
 100         int available;
 101         int size;
 102         unsigned char *buf;
 103         ssize_t count;
 104
 105         if (ioctl(rpc->fd, FIONREAD, &available) != 0) {
 106                 rpc_set_error(rpc, "Ioctl FIONREAD returned error : %d. Closing socket.", errno);
 107                 return -1;
 108         }
 109         if (available == 0) {
 110                 rpc_set_error(rpc, "Socket has been closed");
 111                 return -2;
 112         }
 113         size = rpc->insize - rpc->inpos + available;
 114         buf = malloc(size);
 115         if (buf == NULL) {
 116                 rpc_set_error(rpc, "Out of memory: failed to allocate %d bytes for input buffer. Closing socket.", size);
 117                 return -3;
 118         }
 119         if (rpc->insize > rpc->inpos) {
 120                 memcpy(buf, rpc->inbuf + rpc->inpos, rpc->insize - rpc->inpos);
 121                 rpc->insize -= rpc->inpos;
 122                 rpc->inpos   = 0;
 123         }
 124
 125         count = read(rpc->fd, buf + rpc->insize, available);
 126         if (count == -1) {
 127                 if (errno == EINTR) {
 128                         free(buf);
 129                         buf = NULL;
 130                         return 0;
 131                 }
 132                 rpc_set_error(rpc, "Read from socket failed, errno:%d. Closing socket.", errno);
 133                 free(buf);
 134                 buf = NULL;
 135                 return -4;
 136         }
 137
 138         if (rpc->inbuf != NULL) {
 139                 free(rpc->inbuf);
 140         }
 141         rpc->inbuf   = (char *)buf;
 142         rpc->insize += count;
 143
 144         while (1) {
 145                 if (rpc->insize - rpc->inpos < 4) {
 146                         return 0;
 147                 }
 148                 count = rpc_get_pdu_size(rpc->inbuf + rpc->inpos);
 149                 if (rpc->insize + rpc->inpos < count) {
 150                         return 0;
 151                 }
 152                 if (rpc_process_pdu(rpc, rpc->inbuf + rpc->inpos, count) != 0) {
 153                         rpc_set_error(rpc, "Invalid/garbage pdu received from server. Closing socket");
 154                         return -5;
 155                 }
 156                 rpc->inpos += count;
 157                 if (rpc->inpos == rpc->insize) {
 158                         free(rpc->inbuf);
 159                         rpc->inbuf = NULL;
 160                         rpc->insize = 0;
 161                         rpc->inpos = 0;
 162                 }
 163         }
 164         return 0;
 165 }
 166
 167
 168
 169 int rpc_service(struct rpc_context *rpc, int revents)
 170 {
 171         if (revents & POLLERR) {
 172                 printf("rpc_service: POLLERR, socket error\n");
 173                 if (rpc->is_connected == 0) {
 174                         rpc_set_error(rpc, "Failed to connect to server socket.");
 175                 } else {
 176                         rpc_set_error(rpc, "Socket closed with POLLERR");
 177                 }
 178                 rpc->connect_cb(rpc, RPC_STATUS_ERROR, rpc->error_string, rpc->connect_data);
 179                 return -1;
 180         }
 181         if (revents & POLLHUP) {
 182                 printf("rpc_service: POLLHUP, socket error\n");
 183                 rpc_set_error(rpc, "Socket failed with POLLHUP");
 184                 rpc->connect_cb(rpc, RPC_STATUS_ERROR, rpc->error_string, rpc->connect_data);
 185                 return -2;
 186         }
 187
 188         if (rpc->is_connected == 0 && rpc->fd != -1 && revents&POLLOUT) {
 189                 rpc->is_connected = 1;
 190                 rpc->connect_cb(rpc, RPC_STATUS_SUCCESS, NULL, rpc->connect_data);
 191                 return 0;
 192         }
 193
 194         if (revents & POLLOUT && rpc->outqueue != NULL) {
 195                 if (rpc_write_to_socket(rpc) != 0) {
 196                         printf("write to socket failed\n");
 197                         return -3;
 198                 }
 199         }
 200
 201         if (revents & POLLIN) {
 202                 if (rpc_read_from_socket(rpc) != 0) {
 203                         rpc_disconnect(rpc, rpc_get_error(rpc));
 204                         return -4;
 205                 }
 206         }
 207
 208         return 0;
 209 }
 210
 211
 212 int rpc_connect_async(struct rpc_context *rpc, const char *server, int port, int use_privileged_port, rpc_cb cb, void *private_data)
 213 {
 214         struct sockaddr_storage s;
 215         struct sockaddr_in *sin = (struct sockaddr_in *)&s;
 216         int socksize;
 217
 218         if (rpc->fd != -1) {
 219                 rpc_set_error(rpc, "Trying to connect while already connected");
 220                 printf("%s\n", rpc->error_string);
 221                 return -1;
 222         }
 223
 224         sin->sin_family = AF_INET;
 225         sin->sin_port   = htons(port);
 226         if (inet_pton(AF_INET, server, &sin->sin_addr) != 1) {
 227                 rpc_set_error(rpc, "Not a valid server ip address");
 228                 printf("%s\n", rpc->error_string);
 229                 return -2;
 230         }
 231
 232         switch (s.ss_family) {
 233         case AF_INET:
 234                 rpc->fd = socket(AF_INET, SOCK_STREAM, 0);
 235                 socksize = sizeof(struct sockaddr_in);
 236                 break;
 237         }
 238
 239         if (rpc->fd == -1) {
 240                 rpc_set_error(rpc, "Failed to open socket");
 241                 printf("%s\n", rpc->error_string);
 242                 return -3;
 243         }
 244
 245         /* if we are root, try to find a privileged port to use (512 - 1023) */
 246         if (geteuid() == 0 && use_privileged_port != 0) {
 247                 struct sockaddr_storage ls;
 248                 int ret, count = 0;
 249                 static int local_port = 0;
 250
 251                 if (local_port == 0) {
 252                         srandom(getpid() ^ time(NULL));
 253                         local_port = random()%512 + 512;
 254                 }
 255
 256                 do {
 257                         count ++;
 258                         if (local_port >= 1024) {
 259                                 local_port = 512;
 260                         }
 261                         switch (s.ss_family) {
 262                         case AF_INET:
 263                                 bzero(&ls, socksize);
 264                                 ((struct sockaddr_in *)&ls)->sin_family      = AF_INET;
 265                                 ((struct sockaddr_in *)&ls)->sin_addr.s_addr = INADDR_ANY;
 266                                 ((struct sockaddr_in *)&ls)->sin_port        = htons(local_port++);
 267                                 break;
 268                         }
 269
 270                         ret  = bind(rpc->fd, (struct sockaddr *)&ls, socksize);
 271                 } while (ret != 0  && count < 50);
 272         }
 273
 274         rpc->connect_cb  = cb;
 275         rpc->connect_data = private_data;
 276
 277         set_nonblocking(rpc->fd);
 278
 279         if (connect(rpc->fd, (struct sockaddr *)&s, socksize) != 0 && errno != EINPROGRESS) {
 280                 rpc_set_error(rpc, "connect() to server failed");
 281                 printf("%s\n", rpc->error_string);
 282                 return -4;
 283         }
 284
 285         return 0;
 286 }
 287
 288 int rpc_disconnect(struct rpc_context *rpc, char *error)
 289 {
 290         if (rpc->fd != -1) {
 291                 close(rpc->fd);
 292         }
 293         rpc->fd  = -1;
 294
 295         rpc->is_connected = 0;
 296
 297         rpc_error_all_pdus(rpc, error);
 298
 299         return 0;
 300 }