zos: use custom proctitle implementation

ZOSLIB uses `argv[0]` to determine the exepath. So it is necessary to
use an implementation of proctitle that does not modify `argv[0]`. Since
there is currently no support for process titles on z/OS, the custom
proctitle implementation simply stores the desired title in memory.

This resolves failure in tests `get_currentexe` and `process_title` on
z/OS.

PR-URL: https://github.com/libuv/libuv/pull/3060
Reviewed-By: Richard Lau <rlau@redhat.com>

CMakeLists.txt

@@ -212,7 +212,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Android")
        src/unix/random-sysctl-linux.c)
 endif()
 
-if(APPLE OR CMAKE_SYSTEM_NAME MATCHES "Android|Linux|OS390")
+if(APPLE OR CMAKE_SYSTEM_NAME MATCHES "Android|Linux")
   list(APPEND uv_sources src/unix/proctitle.c)
 endif()
 
@@ -286,7 +286,8 @@ if(CMAKE_SYSTEM_NAME STREQUAL "OS390")
   list(APPEND uv_sources
        src/unix/pthread-fixes.c
        src/unix/os390.c
-       src/unix/os390-syscalls.c)
+       src/unix/os390-syscalls.c
+       src/unix/os390-proctitle.c)
   list(APPEND uv_cflags
        -q64
        -qascii

src/unix/os390-proctitle.c

@@ -0,0 +1,136 @@
+/* Copyright libuv project contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "internal.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static uv_mutex_t process_title_mutex;
+static uv_once_t process_title_mutex_once = UV_ONCE_INIT;
+static char* process_title = NULL;
+static void* args_mem = NULL;
+
+
+static void init_process_title_mutex_once(void) {
+  uv_mutex_init(&process_title_mutex);
+}
+
+
+char** uv_setup_args(int argc, char** argv) {
+  char** new_argv;
+  size_t size;
+  char* s;
+  int i;
+
+  if (argc <= 0)
+    return argv;
+
+  /* Calculate how much memory we need for the argv strings. */
+  size = 0;
+  for (i = 0; i < argc; i++)
+    size += strlen(argv[i]) + 1;
+
+  /* Add space for the argv pointers. */
+  size += (argc + 1) * sizeof(char*);
+
+  new_argv = uv__malloc(size);
+  if (new_argv == NULL)
+    return argv;
+
+  /* Copy over the strings and set up the pointer table. */
+  s = (char*) &new_argv[argc + 1];
+  for (i = 0; i < argc; i++) {
+    size = strlen(argv[i]) + 1;
+    memcpy(s, argv[i], size);
+    new_argv[i] = s;
+    s += size;
+  }
+  new_argv[i] = NULL;
+
+  args_mem = new_argv;
+  process_title = uv__strdup(argv[0]);
+
+  return new_argv;
+}
+
+
+int uv_set_process_title(const char* title) {
+  char* new_title;
+
+  /* If uv_setup_args wasn't called or failed, we can't continue. */
+  if (args_mem == NULL)
+    return UV_ENOBUFS;
+
+  /* We cannot free this pointer when libuv shuts down,
+   * the process may still be using it.
+   */
+  new_title = uv__strdup(title);
+  if (new_title == NULL)
+    return UV_ENOMEM;
+
+  uv_once(&process_title_mutex_once, init_process_title_mutex_once);
+  uv_mutex_lock(&process_title_mutex);
+
+  if (process_title != NULL)
+    uv__free(process_title);
+
+  process_title = new_title;
+
+  uv_mutex_unlock(&process_title_mutex);
+
+  return 0;
+}
+
+
+int uv_get_process_title(char* buffer, size_t size) {
+  size_t len;
+
+  if (buffer == NULL || size == 0)
+    return UV_EINVAL;
+
+  /* If uv_setup_args wasn't called or failed, we can't continue. */
+  if (args_mem == NULL || process_title == NULL)
+    return UV_ENOBUFS;
+
+  uv_once(&process_title_mutex_once, init_process_title_mutex_once);
+  uv_mutex_lock(&process_title_mutex);
+
+  len = strlen(process_title);
+
+  if (size <= len) {
+    uv_mutex_unlock(&process_title_mutex);
+    return UV_ENOBUFS;
+  }
+
+  strcpy(buffer, process_title);
+
+  uv_mutex_unlock(&process_title_mutex);
+
+  return 0;
+}
+
+
+void uv__process_title_cleanup(void) {
+  uv__free(args_mem);  /* Keep valgrind happy. */
+  args_mem = NULL;
+}

src/unix/os390.c

@@ -869,9 +869,6 @@ update_timeout:
   }
 }
 
-void uv__set_process_title(const char* title) {
-  /* do nothing */
-}
 
 int uv__io_fork(uv_loop_t* loop) {
   /*

src/unix/proctitle.c

@@ -84,10 +84,7 @@ char** uv_setup_args(int argc, char** argv) {
   }
   new_argv[i] = NULL;
 
-  /* argv is not adjacent on z/os, we use just argv[0] on that platform. */
-#ifndef __MVS__
   pt.cap = argv[i - 1] + size - argv[0];
-#endif
 
   args_mem = new_argv;
   process_title = pt;