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 int sock_queue_destructor(struct sock_queue *queue);
  99 static void sock_queue_handler(struct tevent_context *ev,
 100                                struct tevent_fd *fde, uint16_t flags,
 101                                void *private_data);
 102 static void sock_queue_process(struct sock_queue *queue);
 103 static void sock_queue_process_event(struct tevent_context *ev,
 104                                      struct tevent_immediate *im,
 105                                      void *private_data);
 106
 107 struct sock_queue *sock_queue_setup(TALLOC_CTX *mem_ctx,
 108                                     struct tevent_context *ev,
 109                                     int fd,
 110                                     sock_queue_callback_fn_t callback,
 111                                     void *private_data)
 112 {
 113         struct sock_queue *queue;
 114
 115         queue = talloc_zero(mem_ctx, struct sock_queue);
 116         if (queue == NULL) {
 117                 return NULL;
 118         }
 119
 120         queue->ev = ev;
 121         queue->callback = callback;
 122         queue->private_data = private_data;
 123
 124         queue->im = tevent_create_immediate(queue);
 125         if (queue->im == NULL) {
 126                 talloc_free(queue);
 127                 return NULL;
 128         }
 129
 130         queue->queue = tevent_queue_create(queue, "out-queue");
 131         if (queue->queue == NULL) {
 132                 talloc_free(queue);
 133                 return NULL;
 134         }
 135
 136         if (! sock_queue_set_fd(queue, fd)) {
 137                 talloc_free(queue);
 138                 return NULL;
 139         }
 140
 141         talloc_set_destructor(queue, sock_queue_destructor);
 142
 143         return queue;
 144 }
 145
 146 static bool sock_queue_set_fd(struct sock_queue *queue, int fd)
 147 {
 148         TALLOC_FREE(queue->fde);
 149         queue->fd = fd;
 150
 151         if (fd != -1) {
 152                 int ret;
 153
 154                 ret = set_blocking(fd, false);
 155                 if (ret != 0) {
 156                         return false;
 157                 }
 158
 159                 queue->fde = tevent_add_fd(queue->ev, queue, fd,
 160                                            TEVENT_FD_READ,
 161                                            sock_queue_handler, queue);
 162                 if (queue->fde == NULL) {
 163                         return false;
 164                 }
 165                 tevent_fd_set_auto_close(queue->fde);
 166         }
 167
 168         return true;
 169 }
 170
 171 static int sock_queue_destructor(struct sock_queue *queue)
 172 {
 173         TALLOC_FREE(queue->fde);
 174         queue->fd = -1;
 175
 176         return 0;
 177 }
 178
 179 static void sock_queue_handler(struct tevent_context *ev,
 180                                struct tevent_fd *fde, uint16_t flags,
 181                                void *private_data)
 182 {
 183         struct sock_queue *queue = talloc_get_type_abort(
 184                 private_data, struct sock_queue);
 185         int ret, num_ready;
 186         ssize_t nread;
 187
 188         ret = ioctl(queue->fd, FIONREAD, &num_ready);
 189         if (ret != 0) {
 190                 /* Ignore */
 191                 return;
 192         }
 193
 194         if (num_ready == 0) {
 195                 /* descriptor has been closed */
 196                 goto fail;
 197         }
 198
 199         if (num_ready > queue->buflen - queue->end) {
 200                 queue->buf = talloc_realloc_size(queue, queue->buf,
 201                                                  queue->end + num_ready);
 202                 if (queue->buf == NULL) {
 203                         goto fail;
 204                 }
 205                 queue->buflen = queue->end + num_ready;
 206         }
 207
 208         nread = sys_read(queue->fd, queue->buf + queue->end, num_ready);
 209         if (nread < 0) {
 210                 goto fail;
 211         }
 212         queue->end += nread;
 213
 214         sock_queue_process(queue);
 215         return;
 216
 217 fail:
 218         queue->callback(NULL, 0, queue->private_data);
 219 }
 220
 221 static void sock_queue_process(struct sock_queue *queue)
 222 {
 223         uint32_t pkt_size;
 224
 225         if ((queue->end - queue->begin) < sizeof(uint32_t)) {
 226                 /* not enough data */
 227                 return;
 228         }
 229
 230         pkt_size = *(uint32_t *)(queue->buf + queue->begin);
 231         if (pkt_size == 0) {
 232                 D_ERR("Invalid packet of length 0\n");
 233                 queue->callback(NULL, 0, queue->private_data);
 234         }
 235
 236         if ((queue->end - queue->begin) < pkt_size) {
 237                 /* not enough data */
 238                 return;
 239         }
 240
 241         queue->callback(queue->buf + queue->begin, pkt_size,
 242                         queue->private_data);
 243         queue->begin += pkt_size;
 244
 245         if (queue->begin < queue->end) {
 246                 /* more data to be processed */
 247                 tevent_schedule_immediate(queue->im, queue->ev,
 248                                           sock_queue_process_event, queue);
 249         } else {
 250                 TALLOC_FREE(queue->buf);
 251                 queue->buflen = 0;
 252                 queue->begin = 0;
 253                 queue->end = 0;
 254         }
 255 }
 256
 257 static void sock_queue_process_event(struct tevent_context *ev,
 258                                      struct tevent_immediate *im,
 259                                      void *private_data)
 260 {
 261         struct sock_queue *queue = talloc_get_type_abort(
 262                 private_data, struct sock_queue);
 263
 264         sock_queue_process(queue);
 265 }
 266
 267 struct sock_queue_write_state {
 268         uint8_t *pkt;
 269         uint32_t pkt_size;
 270 };
 271
 272 static void sock_queue_trigger(struct tevent_req *req, void *private_data);
 273
 274 int sock_queue_write(struct sock_queue *queue, uint8_t *buf, size_t buflen)
 275 {
 276         struct tevent_req *req;
 277         struct sock_queue_write_state *state;
 278         bool status;
 279
 280         if (buflen >= INT32_MAX) {
 281                 return -1;
 282         }
 283
 284         req = tevent_req_create(queue, &state, struct sock_queue_write_state);
 285         if (req == NULL) {
 286                 return -1;
 287         }
 288
 289         state->pkt = buf;
 290         state->pkt_size = (uint32_t)buflen;
 291
 292         status = tevent_queue_add_entry(queue->queue, queue->ev, req,
 293                                         sock_queue_trigger, queue);
 294         if (! status) {
 295                 talloc_free(req);
 296                 return -1;
 297         }
 298
 299         return 0;
 300 }
 301
 302 static void sock_queue_trigger(struct tevent_req *req, void *private_data)
 303 {
 304         struct sock_queue *queue = talloc_get_type_abort(
 305                 private_data, struct sock_queue);
 306         struct sock_queue_write_state *state = tevent_req_data(
 307                 req, struct sock_queue_write_state);
 308         size_t offset = 0;
 309
 310         do {
 311                 ssize_t nwritten;
 312
 313                 nwritten = sys_write(queue->fd, state->pkt + offset,
 314                                      state->pkt_size - offset);
 315                 if (nwritten < 0) {
 316                         queue->callback(NULL, 0, queue->private_data);
 317                         return;
 318                 }
 319                 offset += nwritten;
 320
 321         } while (offset < state->pkt_size);
 322
 323         tevent_req_done(req);
 324         talloc_free(req);
 325 }