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 static bool sock_queue_set_fd(struct sock_queue *queue, int fd);
  98 static void sock_queue_handler(struct tevent_context *ev,
  99                                struct tevent_fd *fde, uint16_t flags,
 100                                void *private_data);
 101 static void sock_queue_process(struct sock_queue *queue);
 102 static void sock_queue_process_event(struct tevent_context *ev,
 103                                      struct tevent_immediate *im,
 104                                      void *private_data);
 105
 106 struct sock_queue *sock_queue_setup(TALLOC_CTX *mem_ctx,
 107                                     struct tevent_context *ev,
 108                                     int fd,
 109                                     sock_queue_callback_fn_t callback,
 110                                     void *private_data)
 111 {
 112         struct sock_queue *queue;
 113
 114         queue = talloc_zero(mem_ctx, struct sock_queue);
 115         if (queue == NULL) {
 116                 return NULL;
 117         }
 118
 119         queue->ev = ev;
 120         queue->callback = callback;
 121         queue->private_data = private_data;
 122
 123         queue->im = tevent_create_immediate(queue);
 124         if (queue->im == NULL) {
 125                 talloc_free(queue);
 126                 return NULL;
 127         }
 128
 129         queue->queue = tevent_queue_create(queue, "out-queue");
 130         if (queue->queue == NULL) {
 131                 talloc_free(queue);
 132                 return NULL;
 133         }
 134
 135         if (! sock_queue_set_fd(queue, fd)) {
 136                 talloc_free(queue);
 137                 return NULL;
 138         }
 139
 140         return queue;
 141 }
 142
 143 static bool sock_queue_set_fd(struct sock_queue *queue, int fd)
 144 {
 145         TALLOC_FREE(queue->fde);
 146         queue->fd = fd;
 147
 148         if (fd != -1) {
 149                 int ret;
 150
 151                 ret = set_blocking(fd, false);
 152                 if (ret != 0) {
 153                         return false;
 154                 }
 155
 156                 queue->fde = tevent_add_fd(queue->ev, queue, fd,
 157                                            TEVENT_FD_READ,
 158                                            sock_queue_handler, queue);
 159                 if (queue->fde == NULL) {
 160                         return false;
 161                 }
 162                 tevent_fd_set_auto_close(queue->fde);
 163         }
 164
 165         return true;
 166 }
 167
 168 static void sock_queue_handler(struct tevent_context *ev,
 169                                struct tevent_fd *fde, uint16_t flags,
 170                                void *private_data)
 171 {
 172         struct sock_queue *queue = talloc_get_type_abort(
 173                 private_data, struct sock_queue);
 174         int ret, num_ready;
 175         ssize_t nread;
 176
 177         ret = ioctl(queue->fd, FIONREAD, &num_ready);
 178         if (ret != 0) {
 179                 /* Ignore */
 180                 return;
 181         }
 182
 183         if (num_ready == 0) {
 184                 /* descriptor has been closed */
 185                 goto fail;
 186         }
 187
 188         if (num_ready > queue->buflen - queue->end) {
 189                 queue->buf = talloc_realloc_size(queue, queue->buf,
 190                                                  queue->end + num_ready);
 191                 if (queue->buf == NULL) {
 192                         goto fail;
 193                 }
 194                 queue->buflen = queue->end + num_ready;
 195         }
 196
 197         nread = sys_read(queue->fd, queue->buf + queue->end, num_ready);
 198         if (nread < 0) {
 199                 goto fail;
 200         }
 201         queue->end += nread;
 202
 203         sock_queue_process(queue);
 204         return;
 205
 206 fail:
 207         queue->callback(NULL, 0, queue->private_data);
 208 }
 209
 210 static void sock_queue_process(struct sock_queue *queue)
 211 {
 212         uint32_t pkt_size;
 213
 214         if ((queue->end - queue->begin) < sizeof(uint32_t)) {
 215                 /* not enough data */
 216                 return;
 217         }
 218
 219         pkt_size = *(uint32_t *)(queue->buf + queue->begin);
 220         if (pkt_size == 0) {
 221                 D_ERR("Invalid packet of length 0\n");
 222                 queue->callback(NULL, 0, queue->private_data);
 223                 return;
 224         }
 225
 226         if ((queue->end - queue->begin) < pkt_size) {
 227                 /* not enough data */
 228                 return;
 229         }
 230
 231         queue->callback(queue->buf + queue->begin, pkt_size,
 232                         queue->private_data);
 233         queue->begin += pkt_size;
 234
 235         if (queue->begin < queue->end) {
 236                 /* more data to be processed */
 237                 tevent_schedule_immediate(queue->im, queue->ev,
 238                                           sock_queue_process_event, queue);
 239         } else {
 240                 TALLOC_FREE(queue->buf);
 241                 queue->buflen = 0;
 242                 queue->begin = 0;
 243                 queue->end = 0;
 244         }
 245 }
 246
 247 static void sock_queue_process_event(struct tevent_context *ev,
 248                                      struct tevent_immediate *im,
 249                                      void *private_data)
 250 {
 251         struct sock_queue *queue = talloc_get_type_abort(
 252                 private_data, struct sock_queue);
 253
 254         sock_queue_process(queue);
 255 }
 256
 257 struct sock_queue_write_state {
 258         uint8_t *pkt;
 259         uint32_t pkt_size;
 260 };
 261
 262 static void sock_queue_trigger(struct tevent_req *req, void *private_data);
 263
 264 int sock_queue_write(struct sock_queue *queue, uint8_t *buf, size_t buflen)
 265 {
 266         struct tevent_req *req;
 267         struct sock_queue_write_state *state;
 268         bool status;
 269
 270         if (buflen >= INT32_MAX) {
 271                 return -1;
 272         }
 273
 274         req = tevent_req_create(queue, &state, struct sock_queue_write_state);
 275         if (req == NULL) {
 276                 return -1;
 277         }
 278
 279         state->pkt = buf;
 280         state->pkt_size = (uint32_t)buflen;
 281
 282         status = tevent_queue_add_entry(queue->queue, queue->ev, req,
 283                                         sock_queue_trigger, queue);
 284         if (! status) {
 285                 talloc_free(req);
 286                 return -1;
 287         }
 288
 289         return 0;
 290 }
 291
 292 static void sock_queue_trigger(struct tevent_req *req, void *private_data)
 293 {
 294         struct sock_queue *queue = talloc_get_type_abort(
 295                 private_data, struct sock_queue);
 296         struct sock_queue_write_state *state = tevent_req_data(
 297                 req, struct sock_queue_write_state);
 298         size_t offset = 0;
 299
 300         do {
 301                 ssize_t nwritten;
 302
 303                 nwritten = sys_write(queue->fd, state->pkt + offset,
 304                                      state->pkt_size - offset);
 305                 if (nwritten < 0) {
 306                         queue->callback(NULL, 0, queue->private_data);
 307                         return;
 308                 }
 309                 offset += nwritten;
 310
 311         } while (offset < state->pkt_size);
 312
 313         tevent_req_done(req);
 314         talloc_free(req);
 315 }