From: zrj <rimvydas.jasinskas@gmail.com>
Date: Sat, 5 Oct 2019 10:04:12 +0000 (+0300)
Subject: libc: Add __errno_location() for language binding benefits.
X-Git-Tag: v5.8.0rc1~755
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/60d311380ff2bf02a87700a0f3e6eb53e6034920

libc: Add __errno_location() for language binding benefits.

 Some languages have restrictions when it comes to C style TLS handling
 (thread local might be feature-gated) or simply it is inconvenient to
 add various OS specific binding wrappers just to access C errno values.

 The __errno_location() symbol provides externally callable version of
 __error() inline function.

 While there, add __WANT_NO_INLINED___ERROR guard for few python parsers
 in DPorts that are unable to parse inlined __error() code yet.
---

diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
index 32176113ba..838feaf880 100644
--- a/lib/libc/gen/Makefile.inc
+++ b/lib/libc/gen/Makefile.inc
@@ -8,8 +8,9 @@ CFLAGS+=-I${.CURDIR}/../libc/sysvipc
 
 CMAPS+=	${.CURDIR}/gen/Symbol.map
 
-SRCS+=  _once_stub.c _pthread_stubs.c _rand48.c _spinlock_stub.c \
-	_thread_init.c alarm.c arc4random.c assert.c basename.c \
+SRCS+=  __errno_location.c _once_stub.c _pthread_stubs.c _rand48.c \
+	_spinlock_stub.c _thread_init.c \
+	alarm.c arc4random.c assert.c basename.c \
 	clock.c clock_getcpuclockid.c closedir.c confstr.c creat.c \
 	ctermid.c daemon.c devname.c dirfd.c dirname.c disklabel.c disktab.c \
 	dlfcn.c drand48.c dup3.c elf_utils.c erand48.c err.c errlst.c exec.c \
diff --git a/lib/libc/gen/Symbol.map b/lib/libc/gen/Symbol.map
index 564888885f..72423e5b9c 100644
--- a/lib/libc/gen/Symbol.map
+++ b/lib/libc/gen/Symbol.map
@@ -490,6 +490,7 @@ DF506.0 {
 };
 
 DF508.0 {
+    __errno_location;
     getutxuser;
 };
 
diff --git a/lib/libc/gen/__errno_location.c b/lib/libc/gen/__errno_location.c
new file mode 100644
index 0000000000..163f26fdad
--- /dev/null
+++ b/lib/libc/gen/__errno_location.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2019 The DragonFly Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/errno.h>
+
+/*
+ * This function to fetch errno is provided for language binding only.
+ */
+int *
+__errno_location(void)
+{
+  return (__error());
+}
diff --git a/sys/sys/errno.h b/sys/sys/errno.h
index 657e5ec267..2bfa6a9b5c 100644
--- a/sys/sys/errno.h
+++ b/sys/sys/errno.h
@@ -43,15 +43,23 @@
 #if !defined(_KERNEL) || defined(_KERNEL_VIRTUAL)
 __BEGIN_DECLS
 extern __thread int	errno;
+
+int * __errno_location(void);		/* For language bindings only */
 __END_DECLS
 
+/*
+ * Some python parsers unable to parse such __error() inline.
+ */
+#ifdef __WANT_NO_INLINED___ERROR
+#define	errno		(* __errno_location())
+#else
 static __inline int *__error(void)
 {
 	return (&errno);
 }
-
 #define	errno		(* __error())
 #endif
+#endif
 
 #define	EPERM		1		/* Operation not permitted */
 #define	ENOENT		2		/* No such file or directory */