shared mutex fixes

4 files changed, 106 insertions, 26 deletions

diff --git a/build_and_test.sh b/build_and_test.sh
index 4133639..d1a6484 100644
--- a/build_and_test.sh
+++ b/build_and_test.sh
@@ -223,6 +223,7 @@ else
   STATUS=1
 fi
 
+./build/test_interprocess clean
 ./build/test_interprocess reader &
 ./build/test_interprocess writer
 if [ $? -eq 0 ]; then
diff --git a/source/kit/shared_memory.h b/source/kit/shared_memory.h
index 594d4a4..bd910cb 100644
--- a/source/kit/shared_memory.h
+++ b/source/kit/shared_memory.h
@@ -40,6 +40,7 @@ kit_status_t        kit_shared_memory_clean(kit_str_t name);
 
 #ifndef KIT_DISABLE_SHORT_NAMES
 #  define shared_memory_t kit_shared_memory_t
+#  define shared_memory_clean kit_shared_memory_clean
 #  define shared_memory_open kit_shared_memory_open
 #  define shared_memory_close kit_shared_memory_close
 
diff --git a/source/kit/shared_mutex.h b/source/kit/shared_mutex.h
index de5958d..3626939 100644
--- a/source/kit/shared_mutex.h
+++ b/source/kit/shared_mutex.h
@@ -9,6 +9,7 @@
 #include "threads.h"
 
 #include <assert.h>
+#include <string.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -23,22 +24,27 @@ extern "C" {
 #endif
 
 enum {
-  KIT_SHARED_MUTEX_READY,
+  KIT_SHARED_MUTEX_READY = 1,
   KIT_SHARED_MUTEX_LOCKED,
   KIT_SHARED_MUTEX_WRITER
 };
 
-typedef struct {
-  i8 _Atomic state;
-  i32        readers;
+typedef union {
+  struct {
+    i8 _Atomic state;
+    i32        readers;
+  };
+  struct {
+    u8 _pad[16];
+  };
 } kit_shared_mutex_t;
 
 static void kit_shared_mutex_init(kit_shared_mutex_t *m) {
   assert(m != NULL);
+  memset(m, 0, sizeof *m);
 
   atomic_store_explicit(&m->state, KIT_SHARED_MUTEX_READY,
                         memory_order_relaxed);
-  m->readers = 0;
 }
 
 static i8 kit_shared_try_lock(kit_shared_mutex_t *m) {
@@ -58,7 +64,7 @@ static i8 kit_shared_try_lock(kit_shared_mutex_t *m) {
   }
 
   assert(m->readers >= 0);
-  m->readers++;
+  ++m->readers;
 
   i8 prev_state = KIT_SHARED_MUTEX_LOCKED;
   if (!atomic_compare_exchange_strong_explicit(
@@ -66,7 +72,7 @@ static i8 kit_shared_try_lock(kit_shared_mutex_t *m) {
           memory_order_seq_cst, memory_order_seq_cst))
     assert(0);
 
-  return 0;
+  return 1;
 }
 
 static void kit_shared_lock(kit_shared_mutex_t *m) {
@@ -111,7 +117,7 @@ static i8 kit_unique_try_lock(kit_shared_mutex_t *m) {
           memory_order_seq_cst, memory_order_seq_cst))
     return 0;
 
-  i8 is_locked = m->readers == 0;
+  i8 is_locked = (m->readers == 0);
 
   prev_state = KIT_SHARED_MUTEX_WRITER;
   if (!is_locked &&
@@ -147,6 +153,17 @@ static void kit_unique_unlock(kit_shared_mutex_t *m) {
 #  pragma GCC diagnostic pop
 #endif
 
+#ifndef KIT_DISABLE_SHORT_NAMES
+#  define shared_mutex_t kit_shared_mutex_t
+#  define shared_mutex_init kit_shared_mutex_init
+#  define shared_try_lock kit_shared_try_lock
+#  define shared_lock kit_shared_lock
+#  define shared_unlock kit_shared_unlock
+#  define unique_try_lock kit_unique_try_lock
+#  define unique_lock kit_unique_lock
+#  define unique_unlock kit_unique_unlock
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/tests/test_interprocess.c b/source/tests/test_interprocess.c
index cf33086..b41f71f 100644
--- a/source/tests/test_interprocess.c
+++ b/source/tests/test_interprocess.c
@@ -1,19 +1,24 @@
 #include "../kit/shared_memory.h"
+#include "../kit/shared_mutex.h"
 #include "../kit/threads.h"
 
 #include <stdio.h>
 
 #define NAME "kit_test_interprocess"
 
-enum { DATA_SIZE = 64 };
+enum { DATA_SIZE = 64, TIMEOUT = 3 };
+
+typedef struct {
+  shared_mutex_t m;
+  i8             state;
+  i8             bytes[DATA_SIZE];
+} shared_data_t;
 
 enum { STATE_INIT, STATE_READY, STATE_DONE };
 
 int run_writer() {
-  kit_shared_memory_clean(SZ(NAME));
-
-  kit_shared_memory_t mem = kit_shared_memory_open(
-      SZ(NAME), DATA_SIZE, KIT_SHARED_MEMORY_CREATE);
+  shared_memory_t mem = shared_memory_open(
+      SZ(NAME), sizeof(shared_data_t), SHARED_MEMORY_CREATE);
 
   if (mem.status != KIT_OK) {
     printf("%s: kit_shared_memory_open failed.\n", __FUNCTION__);
@@ -21,13 +26,41 @@ int run_writer() {
     return 1;
   }
 
-  mem.bytes[0] = STATE_INIT;
-  for (int i = 1; i < DATA_SIZE; i++) mem.bytes[i] = i;
-  mem.bytes[0] = STATE_READY;
+  shared_data_t *p = (shared_data_t *) mem.bytes;
+
+  shared_mutex_init(&p->m);
+
+  unique_lock(&p->m);
+  p->state = STATE_INIT;
+  unique_unlock(&p->m);
+
+  unique_lock(&p->m);
+  for (int i = 0; i < DATA_SIZE; i++) p->bytes[i] = i;
+  p->state = STATE_READY;
+  unique_unlock(&p->m);
+
+  struct timespec t0;
+  timespec_get(&t0, TIME_UTC);
+
+  shared_lock(&p->m);
+  while (p->state != STATE_DONE) {
+    shared_unlock(&p->m);
 
-  while (mem.bytes[0] != STATE_DONE) thrd_yield();
+    struct timespec t1;
+    timespec_get(&t1, TIME_UTC);
+
+    if (t1.tv_sec - t0.tv_sec > TIMEOUT) {
+      printf("%s: timeout.\n", __FUNCTION__);
+      shared_memory_close(&mem);
+      return 1;
+    }
+
+    thrd_yield();
+    shared_lock(&p->m);
+  }
+  shared_unlock(&p->m);
 
-  if (kit_shared_memory_close(&mem) != KIT_OK) {
+  if (shared_memory_close(&mem) != KIT_OK) {
     printf("%s: kit_shared_memory_close failed.\n", __FUNCTION__);
     fflush(stdout);
     return 1;
@@ -37,12 +70,24 @@ int run_writer() {
 }
 
 int run_reader() {
-  kit_shared_memory_t mem;
+  struct timespec t0;
+  timespec_get(&t0, TIME_UTC);
+
+  shared_memory_t mem;
   for (;;) {
-    mem = kit_shared_memory_open(SZ(NAME), DATA_SIZE,
-                                 KIT_SHARED_MEMORY_OPEN);
+    mem = shared_memory_open(SZ(NAME), sizeof(shared_data_t),
+                             SHARED_MEMORY_OPEN);
     if (mem.status == KIT_OK)
       break;
+
+    struct timespec t1;
+    timespec_get(&t1, TIME_UTC);
+
+    if (t1.tv_sec - t0.tv_sec > TIMEOUT) {
+      printf("%s: timeout.\n", __FUNCTION__);
+      return 1;
+    }
+
     thrd_yield();
   }
 
@@ -52,20 +97,31 @@ int run_reader() {
     return 1;
   }
 
-  while (mem.bytes[0] != STATE_READY) thrd_yield();
+  shared_data_t *p = (shared_data_t *) mem.bytes;
+
+  shared_lock(&p->m);
+  while (p->state != STATE_READY) {
+    shared_unlock(&p->m);
+    thrd_yield();
+    shared_lock(&p->m);
+  }
 
   i32 status = 0;
 
-  for (i32 i = 1; i < DATA_SIZE; i++)
-    if (mem.bytes[i] != i) {
+  for (i32 i = 0; i < DATA_SIZE; i++)
+    if (p->bytes[i] != i) {
       printf("%s: wrong byte %d\n", __FUNCTION__, i);
       fflush(stdout);
       status = 1;
     }
 
-  mem.bytes[0] = STATE_DONE;
+  shared_unlock(&p->m);
 
-  if (kit_shared_memory_close(&mem) != KIT_OK) {
+  unique_lock(&p->m);
+  p->state = STATE_DONE;
+  unique_unlock(&p->m);
+
+  if (shared_memory_close(&mem) != KIT_OK) {
     printf("%s: kit_shared_memory_close failed.\n", __FUNCTION__);
     fflush(stdout);
     status = 1;
@@ -102,6 +158,11 @@ int main(int argc, char **argv) {
   if (strcmp(argv[1], "reader") == 0)
     return run_reader();
 
+  if (strcmp(argv[1], "clean") == 0) {
+    shared_memory_clean(SZ(NAME));
+    return 0;
+  }
+
   printf("Invalid command line argument \"%s\"\n", argv[1]);
   return 1;
 }