Problem: internal reimplementation of strlcpy used by default on Linux

Solution: use libbsd by default when available, and the internal implementation
only as a fallback, to take advantage of Linux distros maintenance of the
string libraries.

CMakeLists.txt

@@ -138,6 +138,25 @@ if (NOT DISABLE_WS)
   endif()
 endif()
 
+if(NOT MSVC)
+  find_package(PkgConfig)
+  option(WITH_LIBBSD "Use libbsd instead of builtin strlcpy" ON)
+  if (WITH_LIBBSD)
+    pkg_check_modules(LIBBSD "libbsd")
+    if (LIBBSD_FOUND)
+      message(STATUS "Using libbsd")
+      include_directories(${LIBBSD_INCLUDE_DIRS})
+      set(pkg_config_names_private "${pkg_config_names_private} libbsd")
+      set(ZMQ_HAVE_LIBBSD 1)
+      link_directories(${LIBBSD_LIBRARY_DIRS})
+      set(OPTIONAL_LIBRARIES ${LIBBSD_LIBRARIES})
+    endif()
+  endif()
+  if (NOT WITH_LIBBSD OR NOT LIBBSD_FOUND)
+    check_cxx_symbol_exists(strlcpy string.h ZMQ_HAVE_STRLCPY)
+  endif()
+endif()
+
 
 # Select curve encryption library, defaults to tweetnacl
 # To use libsodium instead, use --with-libsodium(must be installed)
@@ -460,7 +479,6 @@ if(NOT MSVC)
   check_cxx_symbol_exists(mkdtemp stdlib.h HAVE_MKDTEMP)
   check_cxx_symbol_exists(accept4 sys/socket.h HAVE_ACCEPT4)
   check_cxx_symbol_exists(strnlen string.h HAVE_STRNLEN)
-  check_cxx_symbol_exists(strlcpy string.h ZMQ_HAVE_STRLCPY)
 else()
   set(HAVE_STRNLEN 1)
 endif()
@@ -661,7 +679,6 @@ else()
       "Name pkg-config shall use to find openpgm libraries and include paths"
       FORCE)
 
-    find_package(PkgConfig)
     pkg_check_modules(OPENPGM  ${OPENPGM_PKGCONFIG_NAME})
 
     if(OPENPGM_FOUND)

Makefile.am

@@ -344,11 +344,11 @@ if HAVE_VSCRIPT_COMPLEX
 src_libzmq_la_LDFLAGS += $(VSCRIPT_LDFLAGS),$(srcdir)/src/libzmq.vers
 endif
 
-src_libzmq_la_CPPFLAGS = $(CODE_COVERAGE_CPPFLAGS) $(LIBUNWIND_CFLAGS)
-src_libzmq_la_CFLAGS = $(CODE_COVERAGE_CFLAGS) $(LIBUNWIND_CFLAGS)
+src_libzmq_la_CPPFLAGS = $(CODE_COVERAGE_CPPFLAGS) $(LIBUNWIND_CFLAGS) $(LIBBSD_CFLAGS)
+src_libzmq_la_CFLAGS = $(CODE_COVERAGE_CFLAGS) $(LIBUNWIND_CFLAGS) $(LIBBSD_CFLAGS)
 src_libzmq_la_CXXFLAGS = @LIBZMQ_EXTRA_CXXFLAGS@ $(CODE_COVERAGE_CXXFLAGS) \
-	$(LIBUNWIND_CFLAGS)
-src_libzmq_la_LIBADD = $(CODE_COVERAGE_LDFLAGS) $(LIBUNWIND_LIBS)
+	$(LIBUNWIND_CFLAGS) $(LIBBSD_CFLAGS)
+src_libzmq_la_LIBADD = $(CODE_COVERAGE_LDFLAGS) $(LIBUNWIND_LIBS) $(LIBBSD_LIBS)
 
 if USE_NSS
 src_libzmq_la_CPPFLAGS += ${NSS3_CFLAGS}
@@ -841,10 +841,10 @@ tests_test_security_curve_SOURCES += \
 endif
 
 tests_test_security_curve_LDADD = \
-        ${TESTUTIL_LIBS} src/libzmq.la $(LIBUNWIND_LIBS)
+        ${TESTUTIL_LIBS} src/libzmq.la $(LIBUNWIND_LIBS) $(LIBBSD_LIBS)
 tests_test_security_curve_CPPFLAGS = \
         ${TESTUTIL_CPPFLAGS} \
-	${LIBUNWIND_CFLAGS}
+	${LIBUNWIND_CFLAGS}  ${LIBBSD_CFLAGS}
 
 if USE_LIBSODIUM
 tests_test_security_curve_CPPFLAGS += \

builds/cmake/platform.hpp.in

@@ -52,6 +52,7 @@
 #cmakedefine HAVE_ACCEPT4
 #cmakedefine HAVE_STRNLEN
 #cmakedefine ZMQ_HAVE_STRLCPY
+#cmakedefine ZMQ_HAVE_LIBBSD
 
 #cmakedefine ZMQ_HAVE_IPC
 

configure.ac

@@ -751,19 +751,44 @@ AC_COMPILE_IFELSE(
 		AC_MSG_RESULT([no])
 ])
 
-# string.h doesn't seem to be included by default in Fedora 30
-AC_MSG_CHECKING([whether strlcpy is available])
-AC_COMPILE_IFELSE(
-	[AC_LANG_PROGRAM(
-		[[#include <string.h>]],
-		[[char buf [100]; size_t bar = strlcpy (buf, "foo", 100); (void)bar; return 0;]])
-	],[
-		AC_MSG_RESULT([yes])
-		AC_DEFINE(ZMQ_HAVE_STRLCPY, [1],
-		    [strlcpy is available])
-	],[
-		AC_MSG_RESULT([no])
-])
+AC_ARG_ENABLE([libbsd],
+    [AS_HELP_STRING([--enable-libbsd],
+        [enable libbsd [default=auto]])],
+    [enable_libbsd=$enableval],
+    [enable_libbsd="auto"])
+
+if test "x$enable_libbsd" != "xno"; then
+    PKG_CHECK_MODULES(LIBBSD, [libbsd],
+        [
+            AC_DEFINE(ZMQ_HAVE_LIBBSD, 1, [The libbsd library is to be used])
+            AC_SUBST([LIBBSD_CFLAGS])
+            AC_SUBST([LIBBSD_LIBS])
+            PKGCFG_NAMES_PRIVATE="$PKGCFG_NAMES_PRIVATE libbsd"
+            found_libbsd="yes"
+        ],
+        [
+            found_libbsd="no"
+            if test "x$enable_libbsd" = "xyes"; then
+                AC_MSG_ERROR([Cannot find libbsd])
+            else
+                AC_MSG_WARN([Cannot find libbsd])
+            fi
+        ])
+fi
+if test "x$found_libbsd" != "xyes"; then
+    AC_MSG_CHECKING([whether strlcpy is available])
+    AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM(
+            [[#include <string.h>]],
+            [[char buf [100]; size_t bar = strlcpy (buf, "foo", 100); (void)bar; return 0;]])
+        ],[
+            AC_MSG_RESULT([yes])
+            AC_DEFINE(ZMQ_HAVE_STRLCPY, [1],
+                [strlcpy is available])
+        ],[
+            AC_MSG_RESULT([no])
+    ])
+fi
 
 # pthread_setname is non-posix, and there are at least 4 different implementations
 AC_MSG_CHECKING([whether signature of pthread_setname_np() has 1 argument])

packaging/debian/control

@@ -11,6 +11,7 @@ Build-Depends: debhelper (>= 9),
  libunwind-dev | libunwind8-dev | libunwind7-dev,
  libnss3-dev,
  libgnutls28-dev | libgnutls-dev,
+ libbsd-dev,
  pkg-config,
  asciidoc-base | asciidoc, xmlto,
 Standards-Version: 3.9.8
@@ -42,6 +43,7 @@ Depends: libzmq5 (= ${binary:Version}), ${misc:Depends},
  libunwind-dev | libunwind8-dev | libunwind7-dev,
  libnss3-dev,
  libgnutls28-dev | libgnutls-dev,
+ libbsd-dev,
 Conflicts: libzmq-dev, libzmq5-dev
 Replaces: libzmq5-dev
 Provides: libzmq5-dev

packaging/debian/zeromq.dsc.obs

@@ -6,7 +6,7 @@ Version: 4.3.3
 Maintainer: libzmq Developers <zeromq-dev@lists.zeromq.org>
 Homepage: http://www.zeromq.org/
 Standards-Version: 3.9.8
-Build-Depends: debhelper (>= 9), dh-autoreconf, libkrb5-dev, libpgm-dev, libnorm-dev, libsodium-dev, libunwind-dev | libunwind8-dev | libunwind7-dev, libnss3-dev, libgnutls28-dev | libgnutls-dev, pkg-config, asciidoc-base | asciidoc, xmlto
+Build-Depends: debhelper (>= 9), dh-autoreconf, libkrb5-dev, libpgm-dev, libnorm-dev, libsodium-dev, libunwind-dev | libunwind8-dev | libunwind7-dev, libnss3-dev, libgnutls28-dev | libgnutls-dev, libbsd-dev, pkg-config, asciidoc-base | asciidoc, xmlto
 Package-List:
  libzmq3-dev deb libdevel optional arch=any
  libzmq5 deb libs optional arch=any

packaging/redhat/zeromq.spec

@@ -19,7 +19,7 @@ URL:           http://www.zeromq.org/
 Source:        http://download.zeromq.org/%{name}-%{version}.tar.gz
 Prefix:        %{_prefix}
 Buildroot:     %{_tmppath}/%{name}-%{version}-%{release}-root
-BuildRequires:  autoconf automake libtool glib2-devel
+BuildRequires:  autoconf automake libtool glib2-devel libbsd-devel
 %if ! (0%{?fedora} > 12 || 0%{?rhel} > 5)
 BuildRequires:  e2fsprogs-devel
 BuildRoot:      %(mktemp -ud %{_tmppath}/%{name}-%{version}-%{release}-XXXXXX)

src/ws_engine.cpp

@@ -74,7 +74,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifdef ZMQ_HAVE_WINDOWS
 #define strcasecmp _stricmp
 #else
-#ifndef ZMQ_HAVE_STRLCPY
+#ifdef ZMQ_HAVE_LIBBSD
+#include <bsd/string.h>
+#elif !defined(ZMQ_HAVE_STRLCPY)
 static size_t strlcpy (char *dest_, const char *src_, const size_t dest_size_)
 {
     size_t remain = dest_size_;