Fix -Woverflow warning for POSIX_RLIMIT_INFINITY on 32-bit

With a 64-bit rlim_t, RLIM_INFINITY does not fit into a 32-bit zend_long
and the implicit conversion warns, which breaks --enable-werror builds.
Register -1 in that case, which posix_setrlimit() maps back to
RLIM_INFINITY. This is the value the truncation produced already, so the
constant does not change on any platform.

Also add a test, as POSIX_RLIMIT_INFINITY was not covered by any test.

Author: marc-mabe

ext/posix/posix.c

@@ -51,6 +51,10 @@
 #define POSIX_PID_MAX INT_MAX
 #endif
 
+/* RLIM_INFINITY does not fit into a 32-bit zend_long if rlim_t is 64-bit.
+ * posix_setrlimit() maps -1 to RLIM_INFINITY, so use that in this case. */
+#define PHP_POSIX_RLIM_INFINITY (RLIM_INFINITY > ZEND_LONG_MAX ? -1 : (zend_long) RLIM_INFINITY)
+
 #include "posix_arginfo.h"
 
 ZEND_DECLARE_MODULE_GLOBALS(posix)

ext/posix/posix.stub.php

@@ -187,7 +187,7 @@
 #ifdef HAVE_SETRLIMIT
 /**
  * @var int
- * @cvalue RLIM_INFINITY
+ * @cvalue PHP_POSIX_RLIM_INFINITY
  */
 const POSIX_RLIMIT_INFINITY = UNKNOWN;
 #endif

ext/posix/posix_arginfo.h

@@ -0,0 +1,34 @@
+--TEST--
+posix_setrlimit() with POSIX_RLIMIT_INFINITY
+--EXTENSIONS--
+posix
+--SKIPIF--
+<?php
+if (!function_exists('posix_setrlimit')) die('skip posix_setrlimit() not found');
+if (posix_getrlimit(POSIX_RLIMIT_CORE)[1] !== 'unlimited') die('skip hard limit of POSIX_RLIMIT_CORE is not unlimited');
+?>
+--FILE--
+<?php
+
+var_dump(posix_setrlimit(POSIX_RLIMIT_CORE, 1024, POSIX_RLIMIT_INFINITY));
+var_dump(posix_getrlimit(POSIX_RLIMIT_CORE));
+
+var_dump(posix_setrlimit(POSIX_RLIMIT_CORE, POSIX_RLIMIT_INFINITY, POSIX_RLIMIT_INFINITY));
+var_dump(posix_getrlimit(POSIX_RLIMIT_CORE));
+
+?>
+--EXPECT--
+bool(true)
+array(2) {
+  [0]=>
+  int(1024)
+  [1]=>
+  string(9) "unlimited"
+}
+bool(true)
+array(2) {
+  [0]=>
+  string(9) "unlimited"
+  [1]=>
+  string(9) "unlimited"
+}