Module Name: src
Committed By: kamil
Date: Sat Feb 1 15:38:46 UTC 2020
Modified Files:
src/lib/libc/gen: pthread_atfork.c
Log Message:
Switch atform allocations from malloc()+free() to mmap()+munmap()
This avoid bootstrapping malloc too early when libc+libpthread are not
ready. It is called through pthread__init() -> _pthread_atfork().
This also helps LLVM Leak Sanitizer to pacify false positive reports.
To generate a diff of this commit:
cvs rdiff -u -r1.10 -r1.11 src/lib/libc/gen/pthread_atfork.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/gen/pthread_atfork.c
diff -u src/lib/libc/gen/pthread_atfork.c:1.10 src/lib/libc/gen/pthread_atfork.c:1.11
--- src/lib/libc/gen/pthread_atfork.c:1.10 Tue Jan 20 18:31:25 2015
+++ src/lib/libc/gen/pthread_atfork.c Sat Feb 1 15:38:46 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_atfork.c,v 1.10 2015/01/20 18:31:25 christos Exp $ */
+/* $NetBSD: pthread_atfork.c,v 1.11 2020/02/01 15:38:46 kamil Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -31,15 +31,17 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: pthread_atfork.c,v 1.10 2015/01/20 18:31:25 christos Exp $");
+__RCSID("$NetBSD: pthread_atfork.c,v 1.11 2020/02/01 15:38:46 kamil Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/queue.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
-#include <sys/queue.h>
#include "reentrant.h"
#ifdef __weak_alias
@@ -73,11 +75,22 @@ static struct atfork_callback_q childq =
static struct atfork_callback *
af_alloc(void)
{
+ void *arena;
+ size_t sz;
if (atfork_builtin.fn == NULL)
return &atfork_builtin;
- return malloc(sizeof(atfork_builtin));
+ /*
+ * Avoid using here malloc() as this function is used on early init
+ * and can prematuraly initialize the malloc library.
+ * malloc() allocations here also confuse the LLVM Leak Sanitizer.
+ */
+ sz = sizeof(atfork_builtin);
+ arena = mmap(NULL, sz, PROT_READ|PROT_WRITE, MAP_ANON, -1, 0);
+ if (arena == MAP_FAILED)
+ return NULL;
+ return arena;
}
static void
@@ -85,7 +98,7 @@ af_free(struct atfork_callback *af)
{
if (af != &atfork_builtin)
- free(af);
+ munmap(af, sizeof(atfork_builtin));
}
int
