From 1e4823ca9904db68c5b42955fd19b5e822c048be Mon Sep 17 00:00:00 2001
From: John Barboza <jbarboza@ca.ibm.com>
Date: Tue, 17 Apr 2018 06:01:57 -0700
Subject: [PATCH] zos: use custom semaphore

The System V semaphores on z/OS require explicit ending of the worker
threads and cleanup at process exit. The user will have to manually
cleanup these resources that are left behind. Instead use the custom
semaphore implementation which uses posix mutexes and condition
variables which are cleaned up automatically on process exit.

PR-URL: https://github.com/libuv/libuv/pull/1805
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
---
 include/uv-os390.h |   2 +-
 src/unix/thread.c  | 101 ++++++---------------------------------------
 2 files changed, 13 insertions(+), 90 deletions(-)

diff --git a/include/uv-os390.h b/include/uv-os390.h
index 39e7384d..0267d74c 100644
--- a/include/uv-os390.h
+++ b/include/uv-os390.h
@@ -22,7 +22,7 @@
 #ifndef UV_MVS_H
 #define UV_MVS_H
 
-#define UV_PLATFORM_SEM_T int
+#define UV_PLATFORM_SEM_T long
 
 #define UV_PLATFORM_LOOP_FIELDS                                               \
   void* ep;                                                                   \
diff --git a/src/unix/thread.c b/src/unix/thread.c
index ada2ffc8..a25c733d 100644
--- a/src/unix/thread.c
+++ b/src/unix/thread.c
@@ -423,87 +423,6 @@ int uv_sem_trywait(uv_sem_t* sem) {
   return UV_EINVAL;  /* Satisfy the compiler. */
 }
 
-#elif defined(__MVS__)
-
-int uv_sem_init(uv_sem_t* sem, unsigned int value) {
-  uv_sem_t semid;
-  int err;
-  union {
-    int val;
-    struct semid_ds* buf;
-    unsigned short* array;
-  } arg;
-
-
-  semid = semget(IPC_PRIVATE, 1, S_IRUSR | S_IWUSR);
-  if (semid == -1)
-    return UV__ERR(errno);
-
-  arg.val = value;
-  if (-1 == semctl(semid, 0, SETVAL, arg)) {
-    err = errno;
-    if (-1 == semctl(*sem, 0, IPC_RMID))
-      abort();
-    return UV__ERR(err);
-  }
-
-  *sem = semid;
-  return 0;
-}
-
-void uv_sem_destroy(uv_sem_t* sem) {
-  if (-1 == semctl(*sem, 0, IPC_RMID))
-    abort();
-}
-
-void uv_sem_post(uv_sem_t* sem) {
-  struct sembuf buf;
-
-  buf.sem_num = 0;
-  buf.sem_op = 1;
-  buf.sem_flg = 0;
-
-  if (-1 == semop(*sem, &buf, 1))
-    abort();
-}
-
-void uv_sem_wait(uv_sem_t* sem) {
-  struct sembuf buf;
-  int op_status;
-
-  buf.sem_num = 0;
-  buf.sem_op = -1;
-  buf.sem_flg = 0;
-
-  do
-    op_status = semop(*sem, &buf, 1);
-  while (op_status == -1 && errno == EINTR);
-
-  if (op_status)
-    abort();
-}
-
-int uv_sem_trywait(uv_sem_t* sem) {
-  struct sembuf buf;
-  int op_status;
-
-  buf.sem_num = 0;
-  buf.sem_op = -1;
-  buf.sem_flg = IPC_NOWAIT;
-
-  do
-    op_status = semop(*sem, &buf, 1);
-  while (op_status == -1 && errno == EINTR);
-
-  if (op_status) {
-    if (errno == EAGAIN)
-      return UV_EAGAIN;
-    abort();
-  }
-
-  return 0;
-}
-
 #else /* !(defined(__APPLE__) && defined(__MACH__)) */
 
 #ifdef __GLIBC__
@@ -517,18 +436,22 @@ int uv_sem_trywait(uv_sem_t* sem) {
  * a pointer to the actual struct we're using underneath. */
 
 static uv_once_t glibc_version_check_once = UV_ONCE_INIT;
-static int glibc_needs_custom_semaphore = 0;
+static int platform_needs_custom_semaphore = 0;
 
 static void glibc_version_check(void) {
   const char* version = gnu_get_libc_version();
-  glibc_needs_custom_semaphore =
+  platform_needs_custom_semaphore =
       version[0] == '2' && version[1] == '.' &&
       atoi(version + 2) < 21;
 }
 
+#elif defined(__MVS__)
+
+#define platform_needs_custom_semaphore 1
+
 #else /* !defined(__GLIBC__) */
 
-#define glibc_needs_custom_semaphore 0
+#define platform_needs_custom_semaphore 0
 
 #endif
 
@@ -670,7 +593,7 @@ int uv_sem_init(uv_sem_t* sem, unsigned int value) {
   uv_once(&glibc_version_check_once, glibc_version_check);
 #endif
 
-  if (glibc_needs_custom_semaphore)
+  if (platform_needs_custom_semaphore)
     return uv__custom_sem_init(sem, value);
   else
     return uv__sem_init(sem, value);
@@ -678,7 +601,7 @@ int uv_sem_init(uv_sem_t* sem, unsigned int value) {
 
 
 void uv_sem_destroy(uv_sem_t* sem) {
-  if (glibc_needs_custom_semaphore)
+  if (platform_needs_custom_semaphore)
     uv__custom_sem_destroy(sem);
   else
     uv__sem_destroy(sem);
@@ -686,7 +609,7 @@ void uv_sem_destroy(uv_sem_t* sem) {
 
 
 void uv_sem_post(uv_sem_t* sem) {
-  if (glibc_needs_custom_semaphore)
+  if (platform_needs_custom_semaphore)
     uv__custom_sem_post(sem);
   else
     uv__sem_post(sem);
@@ -694,7 +617,7 @@ void uv_sem_post(uv_sem_t* sem) {
 
 
 void uv_sem_wait(uv_sem_t* sem) {
-  if (glibc_needs_custom_semaphore)
+  if (platform_needs_custom_semaphore)
     uv__custom_sem_wait(sem);
   else
     uv__sem_wait(sem);
@@ -702,7 +625,7 @@ void uv_sem_wait(uv_sem_t* sem) {
 
 
 int uv_sem_trywait(uv_sem_t* sem) {
-  if (glibc_needs_custom_semaphore)
+  if (platform_needs_custom_semaphore)
     return uv__custom_sem_trywait(sem);
   else
     return uv__sem_trywait(sem);