udebug.c

   1 /*
   2  * udebug - debug ring buffer library
   3  *
   4  * Copyright (C) 2023 Felix Fietkau <nbd@nbd.name>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #define _GNU_SOURCE
  19 #include <sys/types.h>
  20 #include <sys/mman.h>
  21 #include <sys/socket.h>
  22 #include <unistd.h>
  23 #include <string.h>
  24 #include <stdio.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <poll.h>
  28 #include <time.h>
  29 #include "udebug-priv.h"
  30 #include "usock.h"
  31
  32 #define ALIGN(i, sz)    (((i) + (sz) - 1) & ~((sz) - 1))
  33
  34 #ifndef MAP_ANONYMOUS
  35 #define MAP_ANONYMOUS MAP_ANON
  36 #endif
  37
  38 #define UDEBUG_MIN_ALLOC_LEN    128
  39 static struct blob_buf b;
  40
  41 static void __randname(char *template)
  42 {
  43         int i;
  44         struct timespec ts;
  45         unsigned long r;
  46
  47         clock_gettime(CLOCK_REALTIME, &ts);
  48         r = ts.tv_sec + ts.tv_nsec;
  49         for (i=0; i<6; i++, r>>=5)
  50                 template[i] = 'A'+(r&15)+(r&16)*2;
  51 }
  52
  53 int udebug_id_cmp(const void *k1, const void *k2, void *ptr)
  54 {
  55         uint32_t id1 = (uint32_t)(uintptr_t)k1, id2 = (uint32_t)(uintptr_t)k2;
  56         if (id1 < id2)
  57                 return -1;
  58         else if (id1 > id2)
  59                 return 1;
  60         return 0;
  61 }
  62
  63 static inline int
  64 shm_open_anon(char *name)
  65 {
  66         char *template = name + strlen(name) - 6;
  67         int fd;
  68
  69         if (template < name || memcmp(template, "XXXXXX", 6) != 0)
  70                 return -1;
  71
  72         for (int i = 0; i < 100; i++) {
  73                 __randname(template);
  74                 fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
  75                 if (fd >= 0) {
  76                         if (shm_unlink(name) < 0) {
  77                                 close(fd);
  78                                 continue;
  79                         }
  80                         return fd;
  81                 }
  82
  83                 if (fd < 0 && errno != EEXIST)
  84                         return -1;
  85         }
  86
  87         return -1;
  88 }
  89
  90 static void __udebug_disconnect(struct udebug *ctx, bool reconnect)
  91 {
  92         uloop_fd_delete(&ctx->fd);
  93         close(ctx->fd.fd);
  94         ctx->fd.fd = -1;
  95         ctx->poll_handle = -1;
  96         if (ctx->reconnect.cb && reconnect)
  97                 uloop_timeout_set(&ctx->reconnect, 1);
  98 }
  99
 100 uint64_t udebug_timestamp(void)
 101 {
 102         struct timespec ts;
 103         uint64_t val;
 104
 105         clock_gettime(CLOCK_REALTIME, &ts);
 106
 107         val = ts.tv_sec;
 108         val *= UDEBUG_TS_SEC;
 109         val += ts.tv_nsec / 1000;
 110
 111         return val;
 112 }
 113
 114 static int
 115 __udebug_buf_map(struct udebug_buf *buf)
 116 {
 117         void *ptr, *ptr2;
 118
 119         ptr = mmap(NULL, buf->head_size + 2 * buf->data_size, PROT_NONE,
 120                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 121         if (ptr == MAP_FAILED)
 122                 return -1;
 123
 124         ptr2 = mmap(ptr, buf->head_size + buf->data_size,
 125                     PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED, buf->fd, 0);
 126         if (ptr2 != ptr)
 127                 goto err_unmap;
 128
 129         ptr2 = mmap(ptr + buf->head_size + buf->data_size, buf->data_size,
 130                     PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED, buf->fd,
 131                     buf->head_size);
 132         if (ptr2 != ptr + buf->head_size + buf->data_size)
 133                 goto err_unmap;
 134
 135         buf->hdr = ptr;
 136         buf->data = ptr + buf->head_size;
 137         return 0;
 138
 139 err_unmap:
 140         munmap(ptr, buf->head_size + 2 * buf->data_size);
 141         return -1;
 142 }
 143
 144 static int
 145 writev_retry(int fd, struct iovec *iov, int iov_len, int sock_fd)
 146 {
 147         uint8_t fd_buf[CMSG_SPACE(sizeof(int))] = { 0 };
 148         struct msghdr msghdr = { 0 };
 149         struct cmsghdr *cmsg;
 150         int len = 0;
 151         int *pfd;
 152
 153         msghdr.msg_iov = iov,
 154         msghdr.msg_iovlen = iov_len,
 155         msghdr.msg_control = fd_buf;
 156         msghdr.msg_controllen = sizeof(fd_buf);
 157
 158         cmsg = CMSG_FIRSTHDR(&msghdr);
 159         cmsg->cmsg_type = SCM_RIGHTS;
 160         cmsg->cmsg_level = SOL_SOCKET;
 161         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
 162
 163         pfd = (int *) CMSG_DATA(cmsg);
 164         msghdr.msg_controllen = cmsg->cmsg_len;
 165
 166         do {
 167                 ssize_t cur_len;
 168
 169                 if (sock_fd < 0) {
 170                         msghdr.msg_control = NULL;
 171                         msghdr.msg_controllen = 0;
 172                 } else {
 173                         *pfd = sock_fd;
 174                 }
 175
 176                 cur_len = sendmsg(fd, &msghdr, 0);
 177                 if (cur_len < 0) {
 178                         struct pollfd pfd = {
 179                                 .fd = fd,
 180                                 .events = POLLOUT
 181                         };
 182
 183                         switch(errno) {
 184                         case EAGAIN:
 185                                 poll(&pfd, 1, -1);
 186                                 break;
 187                         case EINTR:
 188                                 break;
 189                         default:
 190                                 return -1;
 191                         }
 192                         continue;
 193                 }
 194
 195                 if (len > 0)
 196                         sock_fd = -1;
 197
 198                 len += cur_len;
 199                 while (cur_len >= (ssize_t) iov->iov_len) {
 200                         cur_len -= iov->iov_len;
 201                         iov_len--;
 202                         iov++;
 203                         if (!iov_len)
 204                                 return len;
 205                 }
 206                 iov->iov_base += cur_len;
 207                 iov->iov_len -= cur_len;
 208                 msghdr.msg_iov = iov;
 209                 msghdr.msg_iovlen = iov_len;
 210         } while (1);
 211
 212         /* Should never reach here */
 213         return -1;
 214 }
 215
 216 static int
 217 recv_retry(int fd, struct iovec *iov, bool wait, int *recv_fd)
 218 {
 219         uint8_t fd_buf[CMSG_SPACE(sizeof(int))] = { 0 };
 220         struct msghdr msghdr = { 0 };
 221         struct cmsghdr *cmsg;
 222         int total = 0;
 223         int bytes;
 224         int *pfd;
 225
 226         msghdr.msg_iov = iov,
 227         msghdr.msg_iovlen = 1,
 228         msghdr.msg_control = fd_buf;
 229         msghdr.msg_controllen = sizeof(fd_buf);
 230
 231         cmsg = CMSG_FIRSTHDR(&msghdr);
 232         cmsg->cmsg_type = SCM_RIGHTS;
 233         cmsg->cmsg_level = SOL_SOCKET;
 234         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
 235
 236         pfd = (int *) CMSG_DATA(cmsg);
 237
 238         while (iov->iov_len > 0) {
 239                 if (recv_fd) {
 240                         msghdr.msg_control = fd_buf;
 241                         msghdr.msg_controllen = cmsg->cmsg_len;
 242                 } else {
 243                         msghdr.msg_control = NULL;
 244                         msghdr.msg_controllen = 0;
 245                 }
 246
 247                 *pfd = -1;
 248                 bytes = recvmsg(fd, &msghdr, 0);
 249                 if (!bytes)
 250                         return -2;
 251                 if (bytes < 0) {
 252                         bytes = 0;
 253                         if (errno == EINTR)
 254                                 continue;
 255
 256                         if (errno != EAGAIN)
 257                                 return -2;
 258                 }
 259                 if (!wait && !bytes)
 260                         return 0;
 261
 262                 if (recv_fd)
 263                         *recv_fd = *pfd;
 264                 else if (*pfd >= 0)
 265                         close(*pfd);
 266
 267                 if (bytes > 0)
 268                         recv_fd = NULL;
 269
 270                 wait = true;
 271                 iov->iov_len -= bytes;
 272                 iov->iov_base += bytes;
 273                 total += bytes;
 274
 275                 if (iov->iov_len > 0) {
 276                         struct pollfd pfd = {
 277                                 .fd = fd,
 278                                 .events = POLLIN
 279                         };
 280                         int ret;
 281                         do {
 282                                 ret = poll(&pfd, 1, UDEBUG_TIMEOUT);
 283                         } while (ret < 0 && errno == EINTR);
 284
 285                         if (!(pfd.revents & POLLIN))
 286                                 return -1;
 287                 }
 288         }
 289
 290         return total;
 291 }
 292
 293 void udebug_send_msg(struct udebug *ctx, struct udebug_client_msg *msg,
 294                      struct blob_attr *meta, int fd)
 295 {
 296         struct iovec iov[2] = {
 297                 { .iov_base = msg, .iov_len = sizeof(*msg) },
 298                 {}
 299         };
 300
 301         if (!meta) {
 302                 blob_buf_init(&b, 0);
 303                 meta = b.head;
 304         }
 305
 306         iov[1].iov_base = meta;
 307         iov[1].iov_len = blob_pad_len(meta);
 308         writev_retry(ctx->fd.fd, iov, ARRAY_SIZE(iov), fd);
 309 }
 310
 311 static void
 312 udebug_buf_msg(struct udebug_buf *buf, enum udebug_client_msg_type type)
 313 {
 314         struct udebug_client_msg msg = {
 315                 .type = type,
 316                 .id = buf->id,
 317         };
 318
 319         udebug_send_msg(buf->ctx, &msg, NULL, -1);
 320 }
 321
 322 static size_t __udebug_headsize(unsigned int ring_size, unsigned int page_size)
 323 {
 324         ring_size *= sizeof(struct udebug_ptr);
 325         return ALIGN(sizeof(struct udebug_hdr) + ring_size, page_size);
 326 }
 327
 328 int udebug_buf_open(struct udebug_buf *buf, int fd, uint32_t ring_size, uint32_t data_size)
 329 {
 330         INIT_LIST_HEAD(&buf->list);
 331         buf->fd = fd;
 332         buf->ring_size = ring_size;
 333         buf->head_size = __udebug_headsize(ring_size, sysconf(_SC_PAGESIZE));
 334         buf->data_size = data_size;
 335
 336         if (buf->ring_size > (1U << 24) || buf->data_size > (1U << 29))
 337                 return -1;
 338
 339         if (__udebug_buf_map(buf))
 340                 return -1;
 341
 342         if (buf->ring_size != buf->hdr->ring_size ||
 343                 buf->data_size != buf->hdr->data_size) {
 344                 munmap(buf->hdr, buf->head_size + 2 * buf->data_size);
 345                 buf->hdr = NULL;
 346                 return -1;
 347         }
 348
 349         return 0;
 350 }
 351
 352 int udebug_buf_init(struct udebug_buf *buf, size_t entries, size_t size)
 353 {
 354         uint32_t pagesz = sysconf(_SC_PAGESIZE);
 355         char filename[] = "/udebug.XXXXXX";
 356         unsigned int order = 12;
 357         uint8_t ring_order = 5;
 358         size_t head_size;
 359         int fd;
 360
 361         INIT_LIST_HEAD(&buf->list);
 362         if (size < pagesz)
 363                 size = pagesz;
 364         while(size > 1U << order)
 365                 order++;
 366         size = 1 << order;
 367         while (entries > 1U << ring_order)
 368                 ring_order++;
 369         entries = 1 << ring_order;
 370
 371         if (size > (1U << 29) || entries > (1U << 24))
 372                 return -1;
 373
 374         head_size = __udebug_headsize(entries, pagesz);
 375         while (ALIGN(sizeof(*buf->hdr) + (entries * 2) * sizeof(struct udebug_ptr), pagesz) == head_size)
 376                 entries *= 2;
 377
 378         fd = shm_open_anon(filename);
 379         if (fd < 0)
 380                 return -1;
 381
 382         if (ftruncate(fd, head_size + size) < 0)
 383                 goto err_close;
 384
 385         buf->head_size = head_size;
 386         buf->data_size = size;
 387         buf->ring_size = entries;
 388         buf->fd = fd;
 389
 390         if (__udebug_buf_map(buf))
 391                 goto err_close;
 392
 393         buf->hdr->ring_size = entries;
 394         buf->hdr->data_size = size;
 395
 396         /* ensure hdr changes are visible */
 397         __sync_synchronize();
 398
 399         return 0;
 400
 401 err_close:
 402         close(fd);
 403         return -1;
 404 }
 405
 406 static void *udebug_buf_alloc(struct udebug_buf *buf, uint32_t ofs, uint32_t len)
 407 {
 408         struct udebug_hdr *hdr = buf->hdr;
 409
 410         hdr->data_used = u32_max(hdr->data_used, ofs + len + 1);
 411
 412         /* ensure that data_used update is visible before clobbering data */
 413         __sync_synchronize();
 414
 415         return udebug_buf_ptr(buf, ofs);
 416 }
 417
 418 uint64_t udebug_buf_flags(struct udebug_buf *buf)
 419 {
 420         struct udebug_hdr *hdr = buf->hdr;
 421         uint64_t flags;
 422
 423         if (!hdr)
 424                 return 0;
 425
 426         flags = hdr->flags[0];
 427         if (sizeof(flags) != sizeof(uintptr_t))
 428                 flags |= ((uint64_t)hdr->flags[1]) << 32;
 429
 430         return flags;
 431 }
 432
 433 void udebug_entry_init_ts(struct udebug_buf *buf, uint64_t timestamp)
 434 {
 435         struct udebug_hdr *hdr = buf->hdr;
 436         struct udebug_ptr *ptr;
 437
 438         if (!hdr)
 439                 return;
 440
 441         ptr = udebug_ring_ptr(hdr, hdr->head);
 442         ptr->start = hdr->data_head;
 443         ptr->len = 0;
 444         ptr->timestamp = timestamp;
 445 }
 446
 447 void *udebug_entry_append(struct udebug_buf *buf, const void *data, uint32_t len)
 448 {
 449         struct udebug_hdr *hdr = buf->hdr;
 450         struct udebug_ptr *ptr;
 451         uint32_t ofs;
 452         void *ret;
 453
 454         if (!hdr)
 455                 return NULL;
 456
 457         ptr = udebug_ring_ptr(hdr, hdr->head);
 458         ofs = ptr->start + ptr->len;
 459         if (ptr->len + len > buf->data_size / 2)
 460                 return NULL;
 461
 462         ret = udebug_buf_alloc(buf, ofs, len);
 463         if (data)
 464                 memcpy(ret, data, len);
 465         ptr->len += len;
 466
 467         return ret;
 468 }
 469
 470 uint16_t udebug_entry_trim(struct udebug_buf *buf, uint16_t len)
 471 {
 472         struct udebug_hdr *hdr = buf->hdr;
 473         struct udebug_ptr *ptr = udebug_ring_ptr(hdr, hdr->head);
 474
 475         if (len)
 476                 ptr->len -= len;
 477
 478         return ptr->len;
 479 }
 480
 481 void udebug_entry_set_length(struct udebug_buf *buf, uint16_t len)
 482 {
 483         struct udebug_hdr *hdr = buf->hdr;
 484         struct udebug_ptr *ptr = udebug_ring_ptr(hdr, hdr->head);
 485
 486         ptr->len = len;
 487 }
 488
 489 int udebug_entry_printf(struct udebug_buf *buf, const char *fmt, ...)
 490 {
 491         va_list ap;
 492         size_t ret;
 493
 494         va_start(ap, fmt);
 495         ret = udebug_entry_vprintf(buf, fmt, ap);
 496         va_end(ap);
 497
 498         return ret;
 499 }
 500
 501 int udebug_entry_vprintf(struct udebug_buf *buf, const char *fmt, va_list ap)
 502 {
 503         struct udebug_hdr *hdr = buf->hdr;
 504         struct udebug_ptr *ptr;
 505         uint32_t ofs;
 506         uint32_t len;
 507         char *str;
 508
 509         if (!hdr)
 510                 return -1;
 511
 512         ptr = udebug_ring_ptr(hdr, hdr->head);
 513         ofs = ptr->start + ptr->len;
 514         if (ptr->len > buf->data_size / 2)
 515                 return -1;
 516
 517         str = udebug_buf_alloc(buf, ofs, UDEBUG_MIN_ALLOC_LEN);
 518         len = vsnprintf(str, UDEBUG_MIN_ALLOC_LEN, fmt, ap);
 519         if (len <= UDEBUG_MIN_ALLOC_LEN)
 520                 goto out;
 521
 522         if (ptr->len + len > buf->data_size / 2)
 523                 return -1;
 524
 525         udebug_buf_alloc(buf, ofs, len + 1);
 526         len = vsnprintf(str, len, fmt, ap);
 527
 528 out:
 529         ptr->len += len;
 530         return 0;
 531 }
 532
 533 void udebug_entry_add(struct udebug_buf *buf)
 534 {
 535         struct udebug_hdr *hdr = buf->hdr;
 536         struct udebug_ptr *ptr = udebug_ring_ptr(hdr, hdr->head);
 537         uint32_t notify;
 538         uint8_t *data;
 539
 540         /* ensure strings are always 0-terminated */
 541         data = udebug_buf_ptr(buf, ptr->start + ptr->len);
 542         *data = 0;
 543         hdr->data_head = ptr->start + ptr->len + 1;
 544
 545         /* ensure that all data changes are visible before advancing head */
 546         __sync_synchronize();
 547
 548         u32_set(&hdr->head, u32_get(&hdr->head) + 1);
 549         if (!u32_get(&hdr->head))
 550                 u32_set(&hdr->head_hi, u32_get(&hdr->head_hi) + 1);
 551
 552         /* ensure that head change is visible */
 553         __sync_synchronize();
 554
 555         notify = __atomic_exchange_n(&hdr->notify, 0, __ATOMIC_RELAXED);
 556         if (notify) {
 557                 struct udebug_client_msg msg = {
 558                         .type = CL_MSG_RING_NOTIFY,
 559                         .id = buf->id,
 560                         .notify_mask = notify,
 561                 };
 562                 blob_buf_init(&b, 0);
 563
 564                 udebug_send_msg(buf->ctx, &msg, b.head, -1);
 565         }
 566 }
 567 void udebug_buf_free(struct udebug_buf *buf)
 568 {
 569         struct udebug *ctx = buf->ctx;
 570
 571         if (!list_empty(&buf->list) && buf->list.prev)
 572                 list_del(&buf->list);
 573
 574         if (ctx && ctx->fd.fd >= 0)
 575                 udebug_buf_msg(buf, CL_MSG_RING_REMOVE);
 576
 577         munmap(buf->hdr, buf->head_size + 2 * buf->data_size);
 578         close(buf->fd);
 579         memset(buf, 0, sizeof(*buf));
 580 }
 581
 582 static void
 583 __udebug_buf_add(struct udebug *ctx, struct udebug_buf *buf)
 584 {
 585         struct udebug_client_msg msg = {
 586                 .type = CL_MSG_RING_ADD,
 587                 .id = buf->id,
 588                 .ring_size = buf->hdr->ring_size,
 589                 .data_size = buf->hdr->data_size,
 590         };
 591         const struct udebug_buf_meta *meta = buf->meta;
 592         void *c;
 593
 594         blob_buf_init(&b, 0);
 595         blobmsg_add_string(&b, "name", meta->name);
 596         c = blobmsg_open_array(&b, "flags");
 597         for (size_t i = 0; i < meta->n_flags; i++) {
 598                 const struct udebug_buf_flag *flag = &meta->flags[i];
 599                 void *e = blobmsg_open_array(&b, NULL);
 600                 blobmsg_add_string(&b, NULL, flag->name);
 601                 blobmsg_add_u64(&b, NULL, flag->mask);
 602                 blobmsg_close_array(&b, e);
 603         }
 604         blobmsg_close_array(&b, c);
 605
 606         udebug_send_msg(ctx, &msg, b.head, buf->fd);
 607 }
 608
 609 int udebug_buf_add(struct udebug *ctx, struct udebug_buf *buf,
 610                    const struct udebug_buf_meta *meta)
 611 {
 612         list_add_tail(&buf->list, &ctx->local_rings);
 613         buf->ctx = ctx;
 614         buf->meta = meta;
 615         buf->id = ctx->next_id++;
 616         buf->hdr->format = meta->format;
 617         buf->hdr->sub_format = meta->sub_format;
 618
 619         if (ctx->fd.fd >= 0)
 620                 __udebug_buf_add(ctx, buf);
 621
 622         return 0;
 623 }
 624
 625 void udebug_init(struct udebug *ctx)
 626 {
 627         INIT_LIST_HEAD(&ctx->local_rings);
 628         avl_init(&ctx->remote_rings, udebug_id_cmp, true, NULL);
 629         ctx->fd.fd = -1;
 630         ctx->poll_handle = -1;
 631 }
 632
 633 static void udebug_reconnect_cb(struct uloop_timeout *t)
 634 {
 635         struct udebug *ctx = container_of(t, struct udebug, reconnect);
 636
 637         if (udebug_connect(ctx, ctx->socket_path) < 0) {
 638                 uloop_timeout_set(&ctx->reconnect, 1000);
 639                 return;
 640         }
 641
 642         udebug_add_uloop(ctx);
 643 }
 644
 645 void udebug_auto_connect(struct udebug *ctx, const char *path)
 646 {
 647         free(ctx->socket_path);
 648         ctx->reconnect.cb = udebug_reconnect_cb;
 649         ctx->socket_path = path ? strdup(path) : NULL;
 650         if (ctx->fd.fd >= 0)
 651                 return;
 652
 653         udebug_reconnect_cb(&ctx->reconnect);
 654 }
 655
 656 int udebug_connect(struct udebug *ctx, const char *path)
 657 {
 658         struct udebug_remote_buf *rb;
 659         struct udebug_buf *buf;
 660
 661         if (ctx->fd.fd >= 0)
 662                 close(ctx->fd.fd);
 663         ctx->fd.fd = -1;
 664
 665         if (!path)
 666                 path = UDEBUG_SOCK_NAME;
 667
 668         ctx->fd.fd = usock(USOCK_UNIX, path, NULL);
 669         if (ctx->fd.fd < 0)
 670                 return -1;
 671
 672         list_for_each_entry(buf, &ctx->local_rings, list)
 673                 __udebug_buf_add(ctx, buf);
 674
 675         avl_for_each_element(&ctx->remote_rings, rb, node) {
 676                 if (!rb->poll)
 677                         continue;
 678
 679                 rb->poll = false;
 680                 udebug_remote_buf_set_poll(ctx, rb, true);
 681         }
 682
 683         return 0;
 684 }
 685
 686 static bool
 687 udebug_recv_msg(struct udebug *ctx, struct udebug_client_msg *msg, int *fd,
 688                 bool wait)
 689 {
 690         struct iovec iov = {
 691                 .iov_base = msg,
 692                 .iov_len = sizeof(*msg)
 693         };
 694         int ret;
 695
 696         ret = recv_retry(ctx->fd.fd, &iov, wait, fd);
 697         if (ret == -2)
 698                 __udebug_disconnect(ctx, true);
 699
 700         return ret == sizeof(*msg);
 701 }
 702
 703 struct udebug_client_msg *__udebug_poll(struct udebug *ctx, int *fd, bool wait)
 704 {
 705         static struct udebug_client_msg msg = {};
 706
 707         while (udebug_recv_msg(ctx, &msg, fd, wait)) {
 708                 struct udebug_remote_buf *rb;
 709                 void *key;
 710
 711                 if (msg.type != CL_MSG_RING_NOTIFY)
 712                         return &msg;
 713
 714                 if (fd && *fd >= 0)
 715                         close(*fd);
 716
 717                 if (!ctx->notify_cb)
 718                         continue;
 719
 720                 key = (void *)(uintptr_t)msg.id;
 721                 rb = avl_find_element(&ctx->remote_rings, key, rb, node);
 722                 if (!rb || !rb->poll)
 723                         continue;
 724
 725                 if (ctx->poll_handle >= 0)
 726                         __atomic_fetch_or(&rb->buf.hdr->notify,
 727                                           1UL << ctx->poll_handle,
 728                                           __ATOMIC_RELAXED);
 729                 ctx->notify_cb(ctx, rb);
 730         }
 731
 732         return NULL;
 733 }
 734
 735 void udebug_poll(struct udebug *ctx)
 736 {
 737         while (__udebug_poll(ctx, NULL, false));
 738 }
 739
 740 static void udebug_fd_cb(struct uloop_fd *fd, unsigned int events)
 741 {
 742         struct udebug *ctx = container_of(fd, struct udebug, fd);
 743
 744         if (fd->eof)
 745                 __udebug_disconnect(ctx, true);
 746
 747         udebug_poll(ctx);
 748 }
 749
 750 void udebug_add_uloop(struct udebug *ctx)
 751 {
 752         if (ctx->fd.registered)
 753                 return;
 754
 755         ctx->fd.cb = udebug_fd_cb;
 756         uloop_fd_add(&ctx->fd, ULOOP_READ);
 757 }
 758
 759 void udebug_free(struct udebug *ctx)
 760 {
 761         struct udebug_remote_buf *rb, *tmp;
 762         struct udebug_buf *buf;
 763
 764         free(ctx->socket_path);
 765         ctx->socket_path = NULL;
 766
 767         __udebug_disconnect(ctx, false);
 768         uloop_timeout_cancel(&ctx->reconnect);
 769
 770         while (!list_empty(&ctx->local_rings)) {
 771                 buf = list_first_entry(&ctx->local_rings, struct udebug_buf, list);
 772                 udebug_buf_free(buf);
 773         }
 774
 775         avl_for_each_element_safe(&ctx->remote_rings, rb, node, tmp)
 776                 udebug_remote_buf_unmap(ctx, rb);
 777 }