2 files changed, 181 insertions, 0 deletions

diff --git a/tests/syscount.c b/tests/syscount.c
new file mode 100644
index 0000000..ec45c15
--- /dev/null
+++ b/tests/syscount.c
@@ -0,0 +1,144 @@
+/* Counts the system calls a run makes, by standing in front of libc.
+
+     cc -O2 -shared -fPIC -o syscount.so tests/syscount.c -ldl
+     LD_PRELOAD=./syscount.so ./opentracker -f conf      (DYLD_INSERT_LIBRARIES on macOS)
+
+   The tally goes to stderr when the process exits. Reading the source tells
+   you which calls a path should make; this tells you which it does make,
+   which is not always the same thing. */
+
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <stdarg.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifdef __linux__
+#include <sys/epoll.h>
+#endif
+
+#define COUNTER(name) static _Atomic long g_##name
+#define BUMP(name)    atomic_fetch_add_explicit(&g_##name, 1, memory_order_relaxed)
+#define REPORT(name)  fprintf(stderr, "  %-14s %10ld\n", #name, atomic_load(&g_##name))
+
+COUNTER(accept);
+COUNTER(accept4);
+COUNTER(read);
+COUNTER(write);
+COUNTER(close);
+COUNTER(fcntl);
+COUNTER(recvfrom);
+COUNTER(sendto);
+COUNTER(epoll_ctl);
+COUNTER(epoll_wait);
+
+typedef int (*fn_accept)(int, struct sockaddr *, socklen_t *);
+typedef int (*fn_accept4)(int, struct sockaddr *, socklen_t *, int);
+typedef ssize_t (*fn_read)(int, void *, size_t);
+typedef ssize_t (*fn_write)(int, const void *, size_t);
+typedef int (*fn_close)(int);
+typedef int (*fn_fcntl)(int, int, ...);
+typedef ssize_t (*fn_recvfrom)(int, void *, size_t, int, struct sockaddr *, socklen_t *);
+typedef ssize_t (*fn_sendto)(int, const void *, size_t, int, const struct sockaddr *, socklen_t);
+
+static fn_accept   real_accept;
+static fn_accept4  real_accept4;
+static fn_read     real_read;
+static fn_write    real_write;
+static fn_close    real_close;
+static fn_fcntl    real_fcntl;
+static fn_recvfrom real_recvfrom;
+static fn_sendto   real_sendto;
+
+/* Resolving lazily keeps the library out of the way until something is
+   actually called, which matters because dlsym itself allocates */
+#define WRAP(name)                                                                                                     \
+  if (!real_##name)                                                                                                    \
+    real_##name = (fn_##name)dlsym(RTLD_NEXT, #name);                                                                  \
+  BUMP(name)
+
+int accept(int s, struct sockaddr *addr, socklen_t *len) {
+  WRAP(accept);
+  return real_accept(s, addr, len);
+}
+
+#ifdef SOCK_NONBLOCK
+int accept4(int s, struct sockaddr *addr, socklen_t *len, int flags) {
+  WRAP(accept4);
+  return real_accept4(s, addr, len, flags);
+}
+#endif
+
+ssize_t read(int fd, void *buf, size_t count) {
+  WRAP(read);
+  return real_read(fd, buf, count);
+}
+
+ssize_t write(int fd, const void *buf, size_t count) {
+  WRAP(write);
+  return real_write(fd, buf, count);
+}
+
+int close(int fd) {
+  WRAP(close);
+  return real_close(fd);
+}
+
+int fcntl(int fd, int cmd, ...) {
+  va_list args;
+  long    arg;
+
+  va_start(args, cmd);
+  arg = va_arg(args, long);
+  va_end(args);
+  WRAP(fcntl);
+  return real_fcntl(fd, cmd, arg);
+}
+
+ssize_t recvfrom(int s, void *buf, size_t len, int flags, struct sockaddr *from, socklen_t *fromlen) {
+  WRAP(recvfrom);
+  return real_recvfrom(s, buf, len, flags, from, fromlen);
+}
+
+ssize_t sendto(int s, const void *buf, size_t len, int flags, const struct sockaddr *to, socklen_t tolen) {
+  WRAP(sendto);
+  return real_sendto(s, buf, len, flags, to, tolen);
+}
+
+#ifdef __linux__
+typedef int (*fn_epoll_ctl)(int, int, int, struct epoll_event *);
+typedef int (*fn_epoll_wait)(int, struct epoll_event *, int, int);
+static fn_epoll_ctl  real_epoll_ctl;
+static fn_epoll_wait real_epoll_wait;
+
+int epoll_ctl(int ep, int op, int fd, struct epoll_event *ev) {
+  WRAP(epoll_ctl);
+  return real_epoll_ctl(ep, op, fd, ev);
+}
+
+int epoll_wait(int ep, struct epoll_event *events, int max, int timeout) {
+  WRAP(epoll_wait);
+  return real_epoll_wait(ep, events, max, timeout);
+}
+#endif
+
+__attribute__((destructor)) static void report(void) {
+  fprintf(stderr, "\n  system calls this run\n");
+  REPORT(accept);
+#ifdef SOCK_NONBLOCK
+  REPORT(accept4);
+#endif
+  REPORT(read);
+  REPORT(write);
+  REPORT(close);
+  REPORT(fcntl);
+  REPORT(recvfrom);
+  REPORT(sendto);
+#ifdef __linux__
+  REPORT(epoll_ctl);
+  REPORT(epoll_wait);
+#endif
+}
diff --git a/tests/t_event.c b/tests/t_event.c
index 5509f19..ad3948f 100644
--- a/tests/t_event.c
+++ b/tests/t_event.c
@@ -4,6 +4,7 @@
    $id$ */
 
 /* System */
+#include <fcntl.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/time.h>
@@ -205,6 +206,41 @@ static void case_unknown_descriptor(void) {
   CHECK_INT(event_del(4096), -1);
 }
 
+/* event_close exists so that the mechanisms which drop a closed descriptor
+   by themselves are not asked to do it twice. The one that keeps its own
+   list has to be told, and forgetting would leave the entry there to be
+   reported for ever, so what is checked here is the silence afterwards. */
+static void case_close_takes_it_out(void) {
+  int other[2], closed, count, i, strays = 0;
+
+  test_case("a closed descriptor is gone from the set and really closed");
+  pair_open();
+  CHECK(sv[0] != -1);
+  CHECK_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, other), 0);
+  CHECK_INT(event_add(sv[0], EVENT_IN, 1), 0);
+  CHECK_INT(event_add(other[0], EVENT_IN, 2), 0);
+
+  closed = sv[0];
+  CHECK_INT(event_close(closed), 0);
+  sv[0] = -1;
+  CHECK_INT(fcntl(closed, F_GETFD), -1);
+
+  /* The survivor is made ready so the wait has something to come back with,
+     and anything left over from the closed one shows up beside it */
+  CHECK_INT((int)write(other[1], "x", 1), 1);
+  count = event_wait(ready, EVENTS, 200);
+  CHECK(count >= 1);
+  for (i = 0; i < count; ++i)
+    if (ready[i].fd != other[0])
+      ++strays;
+  CHECK_INT(strays, 0);
+
+  event_del(other[0]);
+  close(other[0]);
+  close(other[1]);
+  pair_close();
+}
+
 void test_event(void) {
   CHECK_INT(event_init(), 0);
   CHECK(event_mechanism() != NULL);
@@ -217,6 +253,7 @@ void test_event(void) {
   case_delete_from_the_middle();
   case_timeout();
   case_unknown_descriptor();
+  case_close_takes_it_out();
 
   event_deinit();
 }