[PATCH 2/5] m4: support to load modules on OS/2

[KO Myung-Hun]

* m4/modue.c (SYMBOL_PREFIX): New macro for a symbol prefix.
(m4_module_import): Prepend SYMBOL_PREFIX.
(m4__module_open): Add .dll to suffixes for shared libraries.
Truncate a module name up to 8 characters.
Use a system path if m4_path_search() failed.
* m4/path.c (PATH_SEPARATOR): New macro for a PATH separator.
(FILE_SUFFIXES): Add .dll to search module with .dll extension.
(search_path_env_init): Use PATH_SEPARATOR to distinguish a path.
---
 m4/module.c | 31 ++++++++++++++++++++++++++++---
 m4/path.c   |  9 ++++++++-
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/m4/module.c b/m4/module.c
index 6f2a2a9..a4351c3 100644
--- a/m4/module.c
+++ b/m4/module.c
@@ -67,6 +67,12 @@
 
 #define MODULE_SELF_NAME        "!myself!"
 
+#if OS2
+#  define SYMBOL_PREFIX "_"
+#else
+#  define SYMBOL_PREFIX ""
+#endif
+
 static const char*  module_dlerror (void);
 
 static void         install_builtin_table (m4*, m4_module *);
@@ -97,7 +103,9 @@ m4_module_import (m4 *context, const char *module_name,
 
   if (module)
     {
-      symbol_address = dlsym (module->handle, symbol_name);
+      char *import_name = xasprintf (SYMBOL_PREFIX "%s", symbol_name);
+      symbol_address = dlsym (module->handle, import_name);
+      free (import_name);
 
       if (!symbol_address)
         m4_error (context, 0, 0, NULL,
@@ -265,14 +273,31 @@ compare_builtin_CB (const void *a, const void *b)
 m4_module *
 m4__module_open (m4 *context, const char *name, m4_obstack *obs)
 {
-  static const char *  suffixes[]      = { "", ".so", NULL };
+  static const char *  suffixes[]      = { "", ".so", ".dll", NULL };
   m4_module *          module          = NULL;
 
   assert (context);
 
+#if OS2
+  const char *saved_name = name;
+
+  /* OS/2 does not allow a module name longer than 8 characters. So truncate
+     a module name up to 8 characters. */
+  char os2name[8 + 1] = {'\0', };
+  name = strncpy (os2name, name, sizeof (os2name) - 1);
+#endif
+
   char *filepath = m4_path_search (context, name, suffixes);
   void *handle   = NULL;
 
+#if OS2
+  /* if m4_path_search () fails, then use a system path. */
+  if (!filepath)
+    filepath = xstrdup (name);
+
+  name = saved_name;
+#endif
+
   if (filepath)
     {
       handle = dlopen (filepath, RTLD_NOW|RTLD_GLOBAL);
@@ -296,7 +321,7 @@ m4__module_open (m4 *context, const char *name, m4_obstack 
*obs)
 
       /* Find and run any initializing function in the opened module,
          the first time the module is opened.  */
-      char *entry_point = xasprintf ("include_%s", name);
+      char *entry_point = xasprintf (SYMBOL_PREFIX "include_%s", name);
       m4_module_init_func *init_func =
           (m4_module_init_func *) dlsym (handle, entry_point);
       free (entry_point);
diff --git a/m4/path.c b/m4/path.c
index 3a93289..3f89951 100644
--- a/m4/path.c
+++ b/m4/path.c
@@ -37,11 +37,18 @@
 /* Define this to see runtime debug info.  Implied by DEBUG.  */
 /*#define DEBUG_INCL */
 
+#if OS2
+#  define PATH_SEPARATOR ';'
+#else
+#  define PATH_SEPARATOR ':'
+#endif
+
 static const char *FILE_SUFFIXES[] = {
   "",
   ".m4f",
   ".m4",
   ".so",
+  ".dll",
   NULL
 };
 
@@ -100,7 +107,7 @@ search_path_env_init (m4__search_path_info *info, char 
*path, bool isabs)
 
   do
     {
-      path_end = strchr (path, ':');
+      path_end = strchr (path, PATH_SEPARATOR);
       if (path_end)
         *path_end = '\0';
       if (!isabs || *path == '/')
-- 
1.8.5.2