Free environ when RUBY_FREE_AT_EXIT

The environ is malloc'd, so it gets reported as a memory leak. This
commit adds ruby_free_proctitle which frees it during shutdown when
RUBY_FREE_AT_EXIT is set.

    STACK OF 1 INSTANCE OF 'ROOT LEAK: <calloc in ruby_init_setproctitle>':
    5   dyld                                  0x18b7090e0 start + 2360
    4   ruby                                  0x10000e3a8 main + 100  main.c:58
    3   ruby                                  0x1000b4dfc ruby_options + 180  eval.c:121
    2   ruby                                  0x1001c5f70 ruby_process_options + 200  ruby.c:3014
    1   ruby                                  0x10035c9fc ruby_init_setproctitle + 76  setproctitle.c:105
    0   libsystem_malloc.dylib                0x18b8c7b78 _malloc_zone_calloc_instrumented_or_legacy + 100

common.mk

@@ -19320,6 +19320,7 @@ vm.$(OBJEXT): $(top_srcdir)/internal/gc.h
 vm.$(OBJEXT): $(top_srcdir)/internal/hash.h
 vm.$(OBJEXT): $(top_srcdir)/internal/imemo.h
 vm.$(OBJEXT): $(top_srcdir)/internal/inits.h
+vm.$(OBJEXT): $(top_srcdir)/internal/missing.h
 vm.$(OBJEXT): $(top_srcdir)/internal/numeric.h
 vm.$(OBJEXT): $(top_srcdir)/internal/object.h
 vm.$(OBJEXT): $(top_srcdir)/internal/parse.h

internal/missing.h

@@ -13,6 +13,7 @@
 /* missing/setproctitle.c */
 #ifndef HAVE_SETPROCTITLE
 extern void ruby_init_setproctitle(int argc, char *argv[]);
+extern void ruby_free_proctitle(void);
 #endif
 
 #endif /* INTERNAL_MISSING_H */

missing/setproctitle.c

@@ -80,10 +80,20 @@ static char **argv1_addr = NULL;
 
 #endif /* HAVE_SETPROCTITLE */
 
+#if defined(SPT_TYPE) && SPT_TYPE == SPT_REUSEARGV
+# define ALLOCATE_ENVIRON 1
+#else
+# define ALLOCATE_ENVIRON 0
+#endif
+
+#if ALLOCATE_ENVIRON
+static char **orig_environ = NULL;
+#endif
+
 void
 compat_init_setproctitle(int argc, char *argv[])
 {
-#if defined(SPT_TYPE) && SPT_TYPE == SPT_REUSEARGV
+#if ALLOCATE_ENVIRON
 	extern char **environ;
 	char *lastargv = NULL;
 	char *lastenvp = NULL;
@@ -100,9 +110,10 @@ compat_init_setproctitle(int argc, char *argv[])
 		return;
 
 	/* Fail if we can't allocate room for the new environment */
-	for (i = 0; envp[i] != NULL; i++)
-		;
-	if ((environ = calloc(i + 1, sizeof(*environ))) == NULL) {
+	for (i = 0; envp[i] != NULL; i++);
+
+	orig_environ = environ = xcalloc(i + 1, sizeof(*environ));
+	if (environ == NULL) {
 		environ = envp;	/* put it back */
 		return;
 	}
@@ -134,6 +145,29 @@ compat_init_setproctitle(int argc, char *argv[])
 #endif /* SPT_REUSEARGV */
 }
 
+void
+ruby_free_proctitle(void)
+{
+#if ALLOCATE_ENVIRON
+	extern char **environ;
+
+	if (!orig_environ) return; /* environ is allocated by OS */
+
+	for (int i = 0; environ[i] != NULL; i++) {
+		xfree(environ[i]);
+	}
+
+	/* ruby_setenv could allocate a new environ, so we need to free both environ
+	 * orig_environ in that case. */
+	if (environ != orig_environ) {
+		xfree(orig_environ);
+		orig_environ = NULL;
+	}
+
+	xfree(environ);
+#endif
+}
+
 #ifndef HAVE_SETPROCTITLE
 
 void

vm.c

@@ -20,6 +20,7 @@
 #include "internal/eval.h"
 #include "internal/gc.h"
 #include "internal/inits.h"
+#include "internal/missing.h"
 #include "internal/object.h"
 #include "internal/proc.h"
 #include "internal/re.h"
@@ -3034,6 +3035,10 @@ ruby_vm_destruct(rb_vm_t *vm)
                 xfree(th->nt);
                 th->nt = NULL;
             }
+
+#ifndef HAVE_SETPROCTITLE
+            ruby_free_proctitle();
+#endif
         }
         else {
             if (th) {