[newlib-cygwin] Make the path length of UNIX domain sockets

[newlib-cygwin] Make the path length of UNIX domain sockets

[Sebastian Huber]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=09e5cb57a0c837c0c442668a8dacea19a1d9522a

commit 09e5cb57a0c837c0c442668a8dacea19a1d9522a
Author: Jonathan T. Looney <jtl@FreeBSD.org>
Date:   Tue Apr 14 15:27:24 2020 +0000

    Make the path length of UNIX domain sockets
    
    specified by a #define. Also, add a comment describing the historical context
    for this length.
    
    Reviewed by:    bz, jhb, kbowling (previous version)
    MFC after:      2 weeks
    Sponsored by:   Netflix, Inc.
    Differential Revision:  https://reviews.freebsd.org/D24272

Diff:
---
 newlib/libc/sys/rtems/include/sys/un.h | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/newlib/libc/sys/rtems/include/sys/un.h b/newlib/libc/sys/rtems/include/sys/un.h
index f83652e07..3c408628c 100644
--- a/newlib/libc/sys/rtems/include/sys/un.h
+++ b/newlib/libc/sys/rtems/include/sys/un.h
@@ -43,13 +43,21 @@ typedef	__sa_family_t	sa_family_t;
 #define	_SA_FAMILY_T_DECLARED
 #endif
 
+/*
+ * Historically, (struct sockaddr) needed to fit inside an mbuf.
+ * For this reason, UNIX domain sockets were therefore limited to
+ * 104 bytes. While this limit is no longer necessary, it is kept for
+ * binary compatibility reasons.
+ */
+#define	SUNPATHLEN	104
+
 /*
  * Definitions for UNIX IPC domain.
  */
 struct sockaddr_un {
 	unsigned char	sun_len;	/* sockaddr len including null */
 	sa_family_t	sun_family;	/* AF_UNIX */
-	char	sun_path[104];		/* path name (gag) */
+	char	sun_path[SUNPATHLEN];	/* path name (gag) */
 };
 
 #if __BSD_VISIBLE