On NetBSD 10.0/i386, I see a test failure of ptsname_r. The cause is that
this function, on NetBSD, clobbers the result buffer even when it fails
with error ERANGE.
This patch adds a workaround.
2024-04-08 Bruno Haible <br...@clisp.org>
ptsname_r: Work around ptsname_r bug on NetBSD 10.0.
* m4/ptsname_r.m4 (gl_FUNC_PTSNAME_R): On NetBSD, arrange to override
ptsname_r.
* lib/ptsname_r.c (ptsname_r): Add workaround for NetBSD bug.
* doc/glibc-functions/ptsname_r.texi: Mention the NetBSD bug.
diff --git a/doc/glibc-functions/ptsname_r.texi
b/doc/glibc-functions/ptsname_r.texi
index 198ebf3fe6..785064a2fe 100644
--- a/doc/glibc-functions/ptsname_r.texi
+++ b/doc/glibc-functions/ptsname_r.texi
@@ -28,6 +28,10 @@
When this function fails, it returns -1 instead of the error code
on some platforms:
macOS 11.1, FreeBSD 14.0, Android 4.3.
+@item
+When this function fails with ERANGE, it stores an empty string as result
+on some platforms:
+NetBSD 10.0.
@end itemize
Portability problems not fixed by Gnulib:
diff --git a/lib/ptsname_r.c b/lib/ptsname_r.c
index 460220b201..cc1ae495ec 100644
--- a/lib/ptsname_r.c
+++ b/lib/ptsname_r.c
@@ -68,11 +68,34 @@ ptsname_r (int fd, char *buf, size_t buflen)
#undef ptsname_r
{
#if HAVE_ESSENTIALLY_WORKING_PTSNAME_R
+# if defined __NetBSD__
+ char tmpbuf[32];
+ if (buf == NULL)
+ return EINVAL;
+ if (buflen >= sizeof (tmpbuf))
+ /* ERANGE should not happen in this case. */
+ return ptsname_r (fd, buf, buflen);
+ else
+ {
+ int ret = ptsname_r (fd, tmpbuf, sizeof (tmpbuf));
+ if (ret != 0)
+ return ret;
+ else
+ {
+ size_t len = strlen (tmpbuf);
+ if (len >= buflen)
+ return ERANGE;
+ memcpy (buf, tmpbuf, len + 1);
+ return 0;
+ }
+ }
+# else
int ret = ptsname_r (fd, buf, buflen);
if (ret == 0)
return 0;
else
return errno;
+# endif
#elif defined __DragonFly__
int saved_errno = errno;
char tmpbuf[5 + 4 + 10 + 1];
diff --git a/m4/ptsname_r.m4 b/m4/ptsname_r.m4
index 4c8826c730..286ccab8c9 100644
--- a/m4/ptsname_r.m4
+++ b/m4/ptsname_r.m4
@@ -1,5 +1,5 @@
# ptsname_r.m4
-# serial 9
+# serial 10
dnl Copyright (C) 2010-2024 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -74,6 +74,13 @@ AC_DEFUN([gl_FUNC_PTSNAME_R]
*yes) ;;
*) REPLACE_PTSNAME_R=1 ;;
esac
+ dnl On NetBSD 10.0, when ptsname_r fails with ERANGE, it clobbers the
+ dnl result buffer. We don't use an AC_RUN_IFELSE test here, because
+ dnl while the bug exists on all platforms, only NetBSD/i386 has the
+ dnl files /dev/ptyp[01] on which the bug becomes apparent.
+ case "$host_os" in
+ netbsd*) REPLACE_PTSNAME_R=1 ;;
+ esac
fi
fi
