gio: use reentrant getservbyname_r() if available

gio/gnetworkaddress.c

@@ -486,10 +486,7 @@ g_network_address_parse (const gchar  *host_and_port,
 
       else
         {
-          struct servent *entry;
-
-          entry = getservbyname (port, "tcp");
-          if (entry == NULL)
+          if (!g_getservbyname_ntohs (port, "tcp", &portnum))
             {
               g_set_error (error, G_IO_ERROR, G_IO_ERROR_INVALID_ARGUMENT,
                            "Unknown service '%s' specified in hostname '%s'",
@@ -501,8 +498,6 @@ g_network_address_parse (const gchar  *host_and_port,
               return NULL;
             }
 
-          portnum = g_ntohs (entry->s_port);
-
 #ifdef HAVE_ENDSERVENT
           endservent ();
 #endif

gio/gnetworking.c

@@ -23,6 +23,7 @@
 #include "config.h"
 
 #include "gnetworking.h"
+#include "gnetworkingprivate.h"
 
 /**
  * SECTION:gnetworking
@@ -76,3 +77,26 @@ g_networking_init (void)
     }
 #endif
 }
+
+gboolean
+g_getservbyname_ntohs (const char *name, const char *proto, guint16 *out_port)
+{
+  struct servent *result;
+
+#ifdef HAVE_GETSERVBYNAME_R
+  struct servent result_buf;
+  char buf[2048];
+  int r;
+
+  r = getservbyname_r (name, proto, &result_buf, buf, sizeof (buf), &result);
+  if (r != 0 || result != &result_buf)
+    result = NULL;
+#else
+  result = getservbyname (name, proto);
+#endif
+
+  if (!result)
+    return FALSE;
+  *out_port = g_ntohs (result->s_port);
+  return TRUE;
+}

gio/gnetworkingprivate.h

@@ -33,6 +33,8 @@ gint g_socket (gint     domain,
                gint     protocol,
                GError **error);
 
+gboolean g_getservbyname_ntohs (const char *name, const char *proto, guint16 *out_port);
+
 G_END_DECLS
 
 #endif /* __G_NETWORKINGPRIVATE_H__ */

gio/gnetworkservice.c

@@ -364,17 +364,17 @@ static GList *
 g_network_service_fallback_targets (GNetworkService *srv)
 {
   GSrvTarget *target;
-  struct servent *entry;
+  gboolean has_port;
   guint16 port;
 
-  entry = getservbyname (srv->priv->service, "tcp");
-  port = entry ? g_ntohs (entry->s_port) : 0;
+  has_port = g_getservbyname_ntohs (srv->priv->service, "tcp", &port);
+
 #ifdef HAVE_ENDSERVENT
   endservent ();
 #endif
 
-  if (entry == NULL)
-      return NULL;
+  if (!has_port)
+    return NULL;
 
   target = g_srv_target_new (srv->priv->domain, port, 0, 0);
   return g_list_append (NULL, target);

meson.build

@@ -756,6 +756,24 @@ if cc.has_function('memalign', prefix: '#include <stdlib.h>\n#include <malloc.h>
   glib_conf.set('HAVE_MEMALIGN', 1)
 endif
 
+# For example on Openbsd, getservbyname_r() has a different signature.
+# https://man.openbsd.org/getservbyname.3
+if cc.compiles('''#include <netdb.h>
+               int main (int argc, char ** argv) {
+                 int (*fcn)(const char *,
+                            const char *,
+                            struct servent *,
+                            char *,
+                            size_t,
+                            struct servent **) = getservbyname_r;
+                 (void) fcn;
+                 return 0;
+               }''',
+               name : 'getservbyname_r()',
+               args: '-Werror=incompatible-pointer-types')
+  glib_conf.set('HAVE_GETSERVBYNAME_R', 1)
+endif
+
 if cc.has_function('_aligned_malloc', prefix: '#include <malloc.h>')
   glib_conf.set('HAVE__ALIGNED_MALLOC', 1)
 endif