From ec9cee7fc2f4407597597b216791d2980d656e5f Mon Sep 17 00:00:00 2001
From: Wouter Wijngaards <wouter@nlnetlabs.nl>
Date: Tue, 27 Oct 2015 13:47:50 +0000
Subject: [PATCH] - portability, replace snprintf if return value broken.

git-svn-id: file:///svn/unbound/trunk@3518 be551aaa-1e26-0410-a405-d3ace91eadb9
---
 config.h.in   |  9 +++++----
 configure     | 42 ++++++++++++++++++++++++++++++++++++++++++
 configure.ac  | 22 +++++++++++++++++++++-
 doc/Changelog |  1 +
 4 files changed, 69 insertions(+), 5 deletions(-)

diff --git a/config.h.in b/config.h.in
index 5eb81c79d..32a9d88c6 100644
--- a/config.h.in
+++ b/config.h.in
@@ -542,6 +542,9 @@
 /* The size of `time_t', as computed by sizeof. */
 #undef SIZEOF_TIME_T
 
+/* define if (v)snprintf does not return length needed, (but length used) */
+#undef SNPRINTF_RET_BROKEN
+
 /* Define to 1 if you have the ANSI C header files. */
 #undef STDC_HEADERS
 
@@ -855,15 +858,13 @@
 #define MAXHOSTNAMELEN 256
 #endif
 
-
-#ifndef HAVE_SNPRINTF
+#if !defined(HAVE_SNPRINTF) || defined(SNPRINTF_RET_BROKEN)
 #define snprintf snprintf_unbound
 #define vsnprintf vsnprintf_unbound
 #include <stdarg.h>
 int snprintf (char *str, size_t count, const char *fmt, ...);
 int vsnprintf (char *str, size_t count, const char *fmt, va_list arg);
-#endif /* HAVE_SNPRINTF */
-
+#endif /* HAVE_SNPRINTF or SNPRINTF_RET_BROKEN */
 
 #ifndef HAVE_INET_PTON
 #define inet_pton inet_pton_unbound
diff --git a/configure b/configure
index 1e729af42..bc763f95b 100755
--- a/configure
+++ b/configure
@@ -18237,6 +18237,48 @@ esac
 fi
 
 
+# test if snprintf return the proper length
+if test "x$ac_cv_func_snprintf" = xyes; then
+    if test c${cross_compiling} = cno; then
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for correct snprintf return value" >&5
+$as_echo_n "checking for correct snprintf return value... " >&6; }
+	if test "$cross_compiling" = yes; then :
+  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot run test program while cross compiling
+See \`config.log' for more details" "$LINENO" 5; }
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_includes_default
+
+int main(void) { return (snprintf(NULL, 0, "test") == 5); }
+
+_ACEOF
+if ac_fn_c_try_run "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+$as_echo "#define SNPRINTF_RET_BROKEN /**/" >>confdefs.h
+
+		case " $LIBOBJS " in
+  *" snprintf.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS snprintf.$ac_objext"
+ ;;
+esac
+
+
+fi
+rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
+  conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+
+    fi
+fi
 ac_fn_c_check_func "$LINENO" "strlcat" "ac_cv_func_strlcat"
 if test "x$ac_cv_func_strlcat" = xyes; then :
   $as_echo "#define HAVE_STRLCAT 1" >>confdefs.h
diff --git a/configure.ac b/configure.ac
index 17036184e..79367280c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1002,6 +1002,20 @@ AC_REPLACE_FUNCS(inet_aton)
 AC_REPLACE_FUNCS(inet_pton)
 AC_REPLACE_FUNCS(inet_ntop)
 AC_REPLACE_FUNCS(snprintf)
+# test if snprintf return the proper length
+if test "x$ac_cv_func_snprintf" = xyes; then
+    if test c${cross_compiling} = cno; then
+	AC_MSG_CHECKING([for correct snprintf return value])
+	AC_RUN_IFELSE([AC_LANG_SOURCE(AC_INCLUDES_DEFAULT
+[[
+int main(void) { return (snprintf(NULL, 0, "test") == 5); }
+]])], [AC_MSG_RESULT(yes)], [
+		AC_MSG_RESULT(no)
+		AC_DEFINE([SNPRINTF_RET_BROKEN], [], [define if (v)snprintf does not return length needed, (but length used)])
+		AC_LIBOBJ(snprintf)
+	  ])
+    fi
+fi
 AC_REPLACE_FUNCS(strlcat)
 AC_REPLACE_FUNCS(strlcpy)
 AC_REPLACE_FUNCS(memmove)
@@ -1241,7 +1255,13 @@ AHX_CONFIG_FORMAT_ATTRIBUTE
 AHX_CONFIG_UNUSED_ATTRIBUTE
 AHX_CONFIG_FSEEKO
 AHX_CONFIG_MAXHOSTNAMELEN
-AHX_CONFIG_SNPRINTF(unbound)
+#if !defined(HAVE_SNPRINTF) || defined(SNPRINTF_RET_BROKEN)
+#define snprintf snprintf_unbound
+#define vsnprintf vsnprintf_unbound
+#include <stdarg.h>
+int snprintf (char *str, size_t count, const char *fmt, ...);
+int vsnprintf (char *str, size_t count, const char *fmt, va_list arg);
+#endif /* HAVE_SNPRINTF or SNPRINTF_RET_BROKEN */
 AHX_CONFIG_INET_PTON(unbound)
 AHX_CONFIG_INET_NTOP(unbound)
 AHX_CONFIG_INET_ATON(unbound)
diff --git a/doc/Changelog b/doc/Changelog
index 620e69a62..2b0b5a66f 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -2,6 +2,7 @@
 	- isblank() compat implementation.
 	- detect libexpat without xml_StopParser function.
 	- portability fixes.
+	- portability, replace snprintf if return value broken.
 
 23 October 2015: Wouter
 	- Fix #714: Document config to block private-address for IPv4
-- 
2.47.2