Replace libowfat's iobatch with our own smaller (and probably only temporary) ot_batch

1 files changed, 348 insertions, 0 deletions

diff --git a/tests/t_batch.c b/tests/t_batch.c
new file mode 100644
index 0000000..02743f1
--- /dev/null
+++ b/tests/t_batch.c
@@ -0,0 +1,348 @@
+/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
+   It is considered beerware. Prost. Skol. Cheers or whatever.
+
+   $id$ */
+
+/* System */
+#include <fcntl.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+/* Opentracker */
+#include "ot_batch.h"
+#include "test.h"
+
+/* The batch writes to a real socket pair, because what is worth pinning down
+   is what it does when the kernel takes only part of what it was offered. */
+
+static char *dup_of(const char *text) {
+  size_t len  = strlen(text);
+  char  *copy = malloc(len);
+
+  memcpy(copy, text, len);
+  return copy;
+}
+
+static void drain(int s, char *into, size_t len) {
+  size_t got = 0;
+
+  while (got < len) {
+    ssize_t r = read(s, into + got, len - got);
+
+    if (r <= 0)
+      break;
+    got += (size_t)r;
+  }
+  into[got] = 0;
+}
+
+static void case_queue_accounting(void) {
+  ot_batch batch;
+
+  memset(&batch, 0, sizeof(batch));
+
+  test_case("a zeroed batch is empty and sends nothing");
+  CHECK_INT(batch_pending(&batch), 0);
+  CHECK_INT(batch_send(-1, &batch), BATCH_DONE);
+
+  test_case("anything queued makes it pending");
+  CHECK_INT(batch_add(&batch, dup_of("hello "), 6), 0);
+  CHECK_INT(batch_add_copy(&batch, "world", 5), 0);
+  CHECK_INT(batch_pending(&batch), 1);
+  CHECK_INT(batch.count, 2);
+
+  batch_reset(&batch);
+  test_case("and a reset empties it");
+  CHECK_INT(batch_pending(&batch), 0);
+  CHECK_PTR(batch.entries, NULL);
+}
+
+static void case_send_in_one_go(void) {
+  ot_batch batch;
+  int      sv[2];
+  char     got[32];
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+
+  test_case("several buffers arrive as one stream, in order");
+  CHECK_INT(batch_add(&batch, dup_of("opentracker"), 11), 0);
+  CHECK_INT(batch_add_copy(&batch, " says ", 6), 0);
+  CHECK_INT(batch_add(&batch, dup_of("hello"), 5), 0);
+  CHECK_INT(batch_send(sv[0], &batch), 22);
+  CHECK_INT(batch_pending(&batch), 0);
+
+  drain(sv[1], got, 22);
+  CHECK_STR(got, "opentracker says hello");
+
+  test_case("and an empty batch reports it has nothing left");
+  CHECK_INT(batch_send(sv[0], &batch), BATCH_DONE);
+
+  batch_reset(&batch);
+  close(sv[0]);
+  close(sv[1]);
+}
+
+/* Send everything the batch holds, reading the other end as we go so the
+   socket never stays full, and return what arrived. */
+static size_t pump(int writer, int reader, ot_batch *batch, char *into, size_t room) {
+  size_t got = 0;
+
+  while (batch_pending(batch) || got < room) {
+    ssize_t r;
+
+    if (batch_pending(batch)) {
+      ssize_t res = batch_send(writer, batch);
+
+      if (res == BATCH_FAILED)
+        break;
+      if (res > 0)
+        continue;
+    }
+
+    r = read(reader, into + got, room - got);
+    if (r <= 0)
+      break;
+    got += (size_t)r;
+  }
+  return got;
+}
+
+static void case_partial_write_resumes(void) {
+  const size_t size = 200000;
+  ot_batch     batch;
+  int          sv[2], sndbuf = 4096;
+  char        *sent, *got;
+  size_t       i, arrived;
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+  setsockopt(sv[0], SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
+  fcntl(sv[0], F_SETFL, fcntl(sv[0], F_GETFL, 0) | O_NONBLOCK);
+
+  sent = malloc(size);
+  got  = malloc(size);
+  for (i = 0; i < size; ++i)
+    sent[i] = (char)(i % 251);
+
+  test_case("a buffer the kernel takes in pieces arrives whole and in order");
+  CHECK_INT(batch_add(&batch, memcpy(malloc(size), sent, size), size), 0);
+  arrived = pump(sv[0], sv[1], &batch, got, size);
+  CHECK_INT(arrived, size);
+  CHECK_INT(batch_pending(&batch), 0);
+  CHECK_MEM(got, sent, size);
+
+  free(sent);
+  free(got);
+  batch_reset(&batch);
+  close(sv[0]);
+  close(sv[1]);
+}
+
+/* writev refuses more than IOV_MAX entries at once, so a long batch has to be
+   sent across several calls. */
+static void case_more_entries_than_one_writev(void) {
+  const size_t entries = 3000, each = 4;
+  ot_batch     batch;
+  int          sv[2], sndbuf = 4096;
+  char        *sent, *got;
+  size_t       i, arrived, refused = 0;
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+  setsockopt(sv[0], SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
+  fcntl(sv[0], F_SETFL, fcntl(sv[0], F_GETFL, 0) | O_NONBLOCK);
+
+  sent = malloc(entries * each);
+  got  = malloc(entries * each);
+
+  test_case("a batch of more entries than writev accepts still arrives whole");
+  for (i = 0; i < entries; ++i) {
+    char piece[4];
+
+    piece[0] = (char)(i), piece[1] = (char)(i >> 8), piece[2] = 'x', piece[3] = 'y';
+    memcpy(sent + i * each, piece, each);
+    if (batch_add(&batch, memcpy(malloc(each), piece, each), each))
+      ++refused;
+  }
+  CHECK_INT(refused, 0);
+  CHECK_INT(batch.count, entries);
+
+  arrived = pump(sv[0], sv[1], &batch, got, entries * each);
+  CHECK_INT(arrived, entries * each);
+  CHECK_MEM(got, sent, entries * each);
+
+  free(sent);
+  free(got);
+  batch_reset(&batch);
+  close(sv[0]);
+  close(sv[1]);
+}
+
+static void case_reset_frees_the_unsent(void) {
+  ot_batch batch;
+  int      sv[2];
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+
+  test_case("a batch torn down mid flight keeps no bytes outstanding");
+  CHECK_INT(batch_add(&batch, dup_of("first"), 5), 0);
+  CHECK_INT(batch_add(&batch, dup_of("second"), 6), 0);
+  CHECK_INT(batch_send(sv[0], &batch), 11);
+  CHECK_INT(batch_add(&batch, dup_of("never sent"), 10), 0);
+  CHECK_INT(batch_pending(&batch), 1);
+
+  /* Whether the unsent buffer is freed is for the sanitizer to say */
+  batch_reset(&batch);
+  CHECK_INT(batch_pending(&batch), 0);
+  CHECK_INT(batch.count, 0);
+
+  close(sv[0]);
+  close(sv[1]);
+}
+
+static void case_closed_socket_is_fatal(void) {
+  ot_batch batch;
+  int      sv[2];
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+  close(sv[1]);
+
+  test_case("writing to a socket whose peer is gone reports a dead connection");
+  CHECK_INT(batch_add(&batch, dup_of("nobody is listening"), 19), 0);
+  CHECK_INT(batch_send(sv[0], &batch), BATCH_FAILED);
+
+  batch_reset(&batch);
+  close(sv[0]);
+}
+
+static void case_vector_is_taken_whole(void) {
+  ot_batch      batch;
+  struct iovec *vector = malloc(3 * sizeof(struct iovec));
+  int           sv[2];
+  char          got[32];
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+
+  test_case("a whole vector is queued in one go, in order");
+  vector[0].iov_base = dup_of("one "), vector[0].iov_len = 4;
+  vector[1].iov_base = dup_of("two "), vector[1].iov_len = 4;
+  vector[2].iov_base = dup_of("three"), vector[2].iov_len = 5;
+  CHECK_INT(batch_add_vector(&batch, vector, 3), 0);
+  free(vector);
+  CHECK_INT(batch.count, 3);
+  CHECK_INT(batch_send(sv[0], &batch), 13);
+
+  drain(sv[1], got, 13);
+  CHECK_STR(got, "one two three");
+
+  batch_reset(&batch);
+  close(sv[0]);
+  close(sv[1]);
+}
+
+/* The entry array starts small and doubles, so crossing that boundary one
+   buffer at a time is worth its own case. */
+static void case_growing_one_entry_at_a_time(void) {
+  const size_t entries = 100;
+  ot_batch     batch;
+  int          sv[2];
+  char         sent[400], got[401];
+  size_t       i, refused = 0;
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+
+  test_case("a batch grown one buffer at a time keeps them all, in order");
+  for (i = 0; i < entries; ++i) {
+    char piece[4];
+
+    piece[0] = (char)('a' + i % 26), piece[1] = (char)('0' + i % 10);
+    piece[2] = (char)('A' + i % 26), piece[3] = '.';
+    memcpy(sent + i * 4, piece, 4);
+    if (batch_add(&batch, memcpy(malloc(4), piece, 4), 4))
+      ++refused;
+  }
+  CHECK_INT(refused, 0);
+  CHECK_INT(batch.count, entries);
+  CHECK_INT(batch_send(sv[0], &batch), (ssize_t)(entries * 4));
+
+  drain(sv[1], got, entries * 4);
+  CHECK_MEM(got, sent, entries * 4);
+
+  batch_reset(&batch);
+  close(sv[0]);
+  close(sv[1]);
+}
+
+/* Appending while earlier entries are still on their way is what a chunked
+   transfer does. Rather than depend on when a kernel decides to block, this
+   takes entries off the front the way a completed send would and checks that
+   the array reuses the space instead of growing. */
+static void case_append_while_sending(void) {
+  const size_t per_round = 12, each = 8;
+  ot_batch     batch;
+  int          sv[2];
+  char         expected[16], got[17];
+  size_t       i, round, refused = 0, space_after_first = 0;
+
+  memset(&batch, 0, sizeof(batch));
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, sv), 0);
+
+  test_case("an array whose front has gone out is reused, not grown");
+  for (round = 0; round < 8; ++round) {
+    for (i = 0; i < per_round; ++i) {
+      /* Distinct per entry, so a move from the wrong index shows up */
+      char *piece = malloc(each);
+
+      memset(piece, (int)('a' + (round * per_round + i) % 26), each);
+      piece[0] = (char)('0' + i);
+      piece[1] = (char)('0' + round);
+      if (batch_add(&batch, piece, each))
+        ++refused;
+    }
+
+    /* All but the last entry have left and been freed */
+    while (batch.count - batch.first > 1)
+      free(batch.entries[batch.first++].iov_base);
+
+    if (!round)
+      space_after_first = batch.space;
+  }
+  CHECK_INT(refused, 0);
+  CHECK_INT(batch.space, space_after_first);
+
+  test_case("and what is still queued survives the move, in order");
+  CHECK_INT(batch.count - batch.first, 1);
+  CHECK_INT(batch_add(&batch, memset(malloc(each), 'Z', each), each), 0);
+  CHECK_INT(batch_send(sv[0], &batch), (ssize_t)(2 * each));
+
+  memset(expected, (int)('a' + (7 * per_round + per_round - 1) % 26), each);
+  expected[0] = (char)('0' + per_round - 1);
+  expected[1] = '7';
+  memset(expected + each, 'Z', each);
+  drain(sv[1], got, 2 * each);
+  CHECK_MEM(got, expected, 2 * each);
+
+  batch_reset(&batch);
+  close(sv[0]);
+  close(sv[1]);
+}
+
+void test_batch(void) {
+  case_queue_accounting();
+  case_send_in_one_go();
+  case_vector_is_taken_whole();
+  case_growing_one_entry_at_a_time();
+  case_append_while_sending();
+  case_partial_write_resumes();
+  case_more_entries_than_one_writev();
+  case_reset_frees_the_unsent();
+  case_closed_socket_is_fatal();
+}