ctdb/common/sock_io.c

   1 /*
   2    Generic Unix-domain Socket I/O
   3
   4    Copyright (C) Amitay Isaacs  2016
   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 3 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, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "replace.h"
  21 #include "system/filesys.h"
  22 #include "system/network.h"
  23
  24 #include <talloc.h>
  25 #include <tevent.h>
  26
  27 #include "lib/util/sys_rw.h"
  28 #include "lib/util/debug.h"
  29 #include "lib/util/blocking.h"
  30
  31 #include "common/logging.h"
  32 #include "common/sock_io.h"
  33
  34 bool sock_clean(const char *sockpath)
  35 {
  36         int ret;
  37
  38         ret = unlink(sockpath);
  39         if (ret == 0) {
  40                 D_WARNING("Removed stale socket %s\n", sockpath);
  41         } else if (errno != ENOENT) {
  42                 D_ERR("Failed to remove stale socket %s\n", sockpath);
  43                 return false;
  44         }
  45
  46         return true;
  47 }
  48
  49 int sock_connect(const char *sockpath)
  50 {
  51         struct sockaddr_un addr;
  52         size_t len;
  53         int fd, ret;
  54
  55         if (sockpath == NULL) {
  56                 D_ERR("Invalid socket path\n");
  57                 return -1;
  58         }
  59
  60         memset(&addr, 0, sizeof(addr));
  61         addr.sun_family = AF_UNIX;
  62         len = strlcpy(addr.sun_path, sockpath, sizeof(addr.sun_path));
  63         if (len >= sizeof(addr.sun_path)) {
  64                 D_ERR("Socket path too long, len=%zu\n", strlen(sockpath));
  65                 return -1;
  66         }
  67
  68         fd = socket(AF_UNIX, SOCK_STREAM, 0);
  69         if (fd == -1) {
  70                 D_ERR("socket() failed, errno=%d\n", errno);
  71                 return -1;
  72         }
  73
  74         ret = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
  75         if (ret == -1) {
  76                 D_ERR("connect() failed, errno=%d\n", errno);
  77                 close(fd);
  78                 return -1;
  79         }
  80
  81         return fd;
  82 }
  83
  84 struct sock_queue {
  85         struct tevent_context *ev;
  86         sock_queue_callback_fn_t callback;
  87         void *private_data;
  88         int fd;
  89
  90         struct tevent_immediate *im;
  91         struct tevent_queue *queue;
  92         struct tevent_fd *fde;
  93         uint8_t *buf;
  94         size_t buflen, begin, end;
  95 };
  96
  97 /*
  98  * The reserved talloc headers, SOCK_QUEUE_OBJ_COUNT,
  99  * and the pre-allocated pool-memory SOCK_QUEUE_POOL_SIZE,
 100  * are used for the sub-objects queue->im, queue->queue, queue->fde
 101  * and queue->buf.
 102  * If the memory allocating sub-objects of struct sock_queue change,
 103  * those values need to be adjusted.
 104  */
 105 #define SOCK_QUEUE_OBJ_COUNT 4
 106 #define SOCK_QUEUE_POOL_SIZE 2048
 107
 108 static bool sock_queue_set_fd(struct sock_queue *queue, int fd);
 109 static void sock_queue_handler(struct tevent_context *ev,
 110                                struct tevent_fd *fde, uint16_t flags,
 111                                void *private_data);
 112 static void sock_queue_process(struct sock_queue *queue);
 113 static void sock_queue_process_event(struct tevent_context *ev,
 114                                      struct tevent_immediate *im,
 115                                      void *private_data);
 116
 117 struct sock_queue *sock_queue_setup(TALLOC_CTX *mem_ctx,
 118                                     struct tevent_context *ev,
 119                                     int fd,
 120                                     sock_queue_callback_fn_t callback,
 121                                     void *private_data)
 122 {
 123         struct sock_queue *queue;
 124
 125         queue = talloc_pooled_object(mem_ctx, struct sock_queue,
 126                                      SOCK_QUEUE_OBJ_COUNT, SOCK_QUEUE_POOL_SIZE);
 127         if (queue == NULL) {
 128                 return NULL;
 129         }
 130         memset(queue, 0, sizeof(struct sock_queue));
 131
 132         queue->ev = ev;
 133         queue->callback = callback;
 134         queue->private_data = private_data;
 135
 136         queue->im = tevent_create_immediate(queue);
 137         if (queue->im == NULL) {
 138                 talloc_free(queue);
 139                 return NULL;
 140         }
 141
 142         queue->queue = tevent_queue_create(queue, "out-queue");
 143         if (queue->queue == NULL) {
 144                 talloc_free(queue);
 145                 return NULL;
 146         }
 147
 148         if (! sock_queue_set_fd(queue, fd)) {
 149                 talloc_free(queue);
 150                 return NULL;
 151         }
 152
 153         return queue;
 154 }
 155
 156 static bool sock_queue_set_fd(struct sock_queue *queue, int fd)
 157 {
 158         TALLOC_FREE(queue->fde);
 159         queue->fd = fd;
 160
 161         if (fd != -1) {
 162                 int ret;
 163
 164                 ret = set_blocking(fd, false);
 165                 if (ret != 0) {
 166                         return false;
 167                 }
 168
 169                 queue->fde = tevent_add_fd(queue->ev, queue, fd,
 170                                            TEVENT_FD_READ,
 171                                            sock_queue_handler, queue);
 172                 if (queue->fde == NULL) {
 173                         return false;
 174                 }
 175                 tevent_fd_set_auto_close(queue->fde);
 176         }
 177
 178         return true;
 179 }
 180
 181 static void sock_queue_handler(struct tevent_context *ev,
 182                                struct tevent_fd *fde, uint16_t flags,
 183                                void *private_data)
 184 {
 185         struct sock_queue *queue = talloc_get_type_abort(
 186                 private_data, struct sock_queue);
 187         int ret, num_ready;
 188         ssize_t nread;
 189
 190         ret = ioctl(queue->fd, FIONREAD, &num_ready);
 191         if (ret != 0) {
 192                 /* Ignore */
 193                 return;
 194         }
 195
 196         if (num_ready == 0) {
 197                 /* descriptor has been closed */
 198                 goto fail;
 199         }
 200
 201         if ((size_t)num_ready > queue->buflen - queue->end) {
 202                 queue->buf = talloc_realloc_size(queue, queue->buf,
 203                                                  queue->end + num_ready);
 204                 if (queue->buf == NULL) {
 205                         goto fail;
 206                 }
 207                 queue->buflen = queue->end + num_ready;
 208         }
 209
 210         nread = sys_read(queue->fd, queue->buf + queue->end, num_ready);
 211         if (nread < 0) {
 212                 goto fail;
 213         }
 214         queue->end += nread;
 215
 216         sock_queue_process(queue);
 217         return;
 218
 219 fail:
 220         queue->callback(NULL, 0, queue->private_data);
 221 }
 222
 223 static void sock_queue_process(struct sock_queue *queue)
 224 {
 225         uint32_t pkt_size;
 226
 227         if ((queue->end - queue->begin) < sizeof(uint32_t)) {
 228                 /* not enough data */
 229                 return;
 230         }
 231
 232         pkt_size = *(uint32_t *)(queue->buf + queue->begin);
 233         if (pkt_size == 0) {
 234                 D_ERR("Invalid packet of length 0\n");
 235                 queue->callback(NULL, 0, queue->private_data);
 236                 return;
 237         }
 238
 239         if ((queue->end - queue->begin) < pkt_size) {
 240                 /* not enough data */
 241                 return;
 242         }
 243
 244         queue->callback(queue->buf + queue->begin, pkt_size,
 245                         queue->private_data);
 246         queue->begin += pkt_size;
 247
 248         if (queue->begin < queue->end) {
 249                 /* more data to be processed */
 250                 tevent_schedule_immediate(queue->im, queue->ev,
 251                                           sock_queue_process_event, queue);
 252         } else {
 253                 TALLOC_FREE(queue->buf);
 254                 queue->buflen = 0;
 255                 queue->begin = 0;
 256                 queue->end = 0;
 257         }
 258 }
 259
 260 static void sock_queue_process_event(struct tevent_context *ev,
 261                                      struct tevent_immediate *im,
 262                                      void *private_data)
 263 {
 264         struct sock_queue *queue = talloc_get_type_abort(
 265                 private_data, struct sock_queue);
 266
 267         sock_queue_process(queue);
 268 }
 269
 270 struct sock_queue_write_state {
 271         uint8_t *pkt;
 272         uint32_t pkt_size;
 273 };
 274
 275 static void sock_queue_trigger(struct tevent_req *req, void *private_data);
 276
 277 int sock_queue_write(struct sock_queue *queue, uint8_t *buf, size_t buflen)
 278 {
 279         struct tevent_req *req;
 280         struct sock_queue_write_state *state;
 281         struct tevent_queue_entry *qentry;
 282
 283         if (buflen >= INT32_MAX) {
 284                 return -1;
 285         }
 286
 287         req = tevent_req_create(queue, &state, struct sock_queue_write_state);
 288         if (req == NULL) {
 289                 return -1;
 290         }
 291
 292         state->pkt = buf;
 293         state->pkt_size = (uint32_t)buflen;
 294
 295         qentry = tevent_queue_add_entry(queue->queue, queue->ev, req,
 296                                         sock_queue_trigger, queue);
 297         if (qentry == NULL) {
 298                 talloc_free(req);
 299                 return -1;
 300         }
 301
 302         return 0;
 303 }
 304
 305 static void sock_queue_trigger(struct tevent_req *req, void *private_data)
 306 {
 307         struct sock_queue *queue = talloc_get_type_abort(
 308                 private_data, struct sock_queue);
 309         struct sock_queue_write_state *state = tevent_req_data(
 310                 req, struct sock_queue_write_state);
 311         size_t offset = 0;
 312
 313         do {
 314                 ssize_t nwritten;
 315
 316                 nwritten = sys_write(queue->fd, state->pkt + offset,
 317                                      state->pkt_size - offset);
 318                 if (nwritten < 0) {
 319                         queue->callback(NULL, 0, queue->private_data);
 320                         return;
 321                 }
 322                 offset += nwritten;
 323
 324         } while (offset < state->pkt_size);
 325
 326         tevent_req_done(req);
 327         talloc_free(req);
 328 }