DSO: Support hot-swapping, enabled with new flag DL_HOTSWAP.

- lib/dl_lib.c:
   - Extract function `DL_invoke()` from `DL_func()`
   - Add functions `DL_get_hotswap()` and `DL_func_hotswap`
      for reloading DSO libraries when `DL_HOTSWAP` is enabled.
- include/dao.h: Add declaration of functions `DL_get_hotswap()` and `DL_func_hotswap`.

- maple/: menu.c: `domenu()`, popupmenu.c: `do_cmd()` & xover.c: `xover()`:
   Do not modify the callback table when `DL_HOTSWAP` is enabled.

- include/cppdef.h: Add macro `DL_HOTSWAP_SCOPE` for declaring DSO object pointers.
- maple/: Do not preserve DSO function pointers when `DL_HOTSWAP` is enabled.

- sample/dreambbs.conf: Add build config `DL_HOTSWAP` for enabling hot-swapping.
- include/global.h: Add `MODULE_DL_HOTSWAP` for `module_flags`.
- so/xyz.c: `x_siteinfo()`: Add information for hot-swapping enabling information.

include/cppdef.h

@@ -176,6 +176,8 @@ template <class T>
 
 /* Macros for managing loading of dynamic libraries */
 
+#include "config.h"
+
 #if NO_SO
 
 #define DL_NAME(module_str, obj)   (&obj)
@@ -185,12 +187,20 @@ template <class T>
 #define DL_NAME_GET(module_str, obj)  (&obj)
 #define DL_NAME_CALL(module_str, func)  func
 
+#undef DL_HOTSWAP
+
 #else  // #if NO_SO
 
 #define DL_NAME(module_str, obj) \
     BINARY_SUFFIX module_str ":" CPP_STR(CPP_UNPAREN_OPT(obj))
-#define DL_GET(dl_name)  DL_get(dl_name)
-#define DL_CALL(dl_name)  DL_func((dl_name), CPP_APPEND_CLOSEPAREN
+
+#ifdef DL_HOTSWAP
+  #define DL_GET(dl_name)  DL_get_hotswap(dl_name)
+  #define DL_CALL(dl_name)  DL_func_hotswap((dl_name), CPP_APPEND_CLOSEPAREN
+#else
+  #define DL_GET(dl_name)  DL_get(dl_name)
+  #define DL_CALL(dl_name)  DL_func((dl_name), CPP_APPEND_CLOSEPAREN
+#endif
 
 #ifdef CPP_TYPEOF
   #define DL_NAME_GET(module_str, obj)  \
@@ -207,6 +217,14 @@ template <class T>
 
 #endif  // #if NO_SO
 
+/* IID.20200103: For making dynamic libraries hot-swappable. */
+#ifdef DL_HOTSWAP
+  #define DL_HOTSWAP_SCOPE  /* Function local */
+#else
+  #define DL_HOTSWAP_SCOPE  static
+#endif
+
+
 /* Macros for emitting warnings */
 
 #define CPP_PRAGMA(arg)  _Pragma(CPP_STR(arg))

include/dao.h

@@ -74,7 +74,9 @@ void archiv32(time_t chrono, char *fname);
 void archiv32m(time_t chrono, char *fname);
 /* dl_lib.c */
 void *DL_get(const char *name);
+void *DL_get_hotswap(const char *name);
 int DL_func(const char *name, ...);
+int DL_func_hotswap(const char *name, ...);
 /* record.c */
 int rec_add(const char *fpath, const void *data, int size);
 int rec_bot(const char *fpath, const void *data, int size);

include/global.h

@@ -541,6 +541,7 @@ VAR const int build_langver       INI(IF_DEF(__cplusplus, (int)__cplusplus, (int
 #define MODULE_GRAYOUT            (1U << 3)
 #define MODULE_M3_USE_BBSLUA      (1U << 4)
 #define MODULE_M3_USE_BBSRUBY     (1U << 5)
+#define MODULE_DL_HOTSWAP         (1U << 6)
 
 #ifdef  HAVE_BBSLUA
 VAR const char bbslua_version_str[]   INI(
@@ -564,6 +565,7 @@ VAR const unsigned int module_flags   INI(
     | MODULE_STATUS(GRAYOUT)
     | MODULE_STATUS(M3_USE_BBSLUA)
     | MODULE_STATUS(M3_USE_BBSRUBY)
+    | MODULE_STATUS(DL_HOTSWAP)
 );
 #undef MODULE_STATUS
 

lib/dl_lib.c

@@ -92,10 +92,29 @@ void *DL_get(const char *name)
     return dlsym(p->handle, t+1);
 }
 
-int DL_func(const char *name, ...)
+void *DL_get_hotswap(const char *name)
+{
+    const char *t = DL_name_delim(name);
+    DL_list *p;
+    if (!t)
+        return NULL;
+
+    p = DL_insert(name, t - name);
+    if (p->handle)              /* Unload the library to load a updated one */
+        dlclose(p->handle);
+
+    p->handle = dlopen(p->path, DL_OPEN_FLAGS);
+    if (!p->handle)
+        return NULL;
+
+    return dlsym(p->handle, t+1);
+}
+
+/* Dynamic library function invokers */
+
+static int DL_invoke(int (*f)(va_list), ...)
 {
     va_list args;
-    int (*f)(va_list) = (int (*)(va_list)) DL_get(name);
     int ret;
 
     if (!f)                      /* not get func */
@@ -107,3 +126,12 @@ int DL_func(const char *name, ...)
 
     return ret;
 }
+
+int DL_func(const char *name, ...)
+{
+    return DL_invoke((int (*)(va_list)) DL_get(name));
+}
+int DL_func_hotswap(const char *name, ...)
+{
+    return DL_invoke((int (*)(va_list)) DL_get_hotswap(name));
+}

maple/acct.c

@@ -986,8 +986,6 @@ void acct_setup(ACCT * u, int adm)
     ACCT x;
     int y, c;
 
-    int (*sm) (char *mail);
-
     int i, num, tmp, mode;
     FILE *flog;
     char *str, buf[80], pass[PLAINPASSLEN];
@@ -998,7 +996,6 @@ void acct_setup(ACCT * u, int adm)
     acct_show(u, (adm) ? 3 : 0);
 
     memcpy(&x, u, sizeof(ACCT));
-    sm = NULL;
 
     if (((u->userlevel & PERM_SYSOP) && strcmp(cuser.userid, u->userid))
         && !check_admin(cuser.userid))
@@ -1083,6 +1080,7 @@ void acct_setup(ACCT * u, int adm)
         }
         if (adm == '3')
         {
+            DL_HOTSWAP_SCOPE int (*sm) (char *mail) = NULL;
             switch (vans("使用程序 i)內部 o)外部 q)取消：[q]"))
             {
             case 'i':

maple/edit.c

@@ -1689,7 +1689,6 @@ vedit(
 {
     textline *vln, *tmp;
     int cc, col, mode, margin, pos;
-    static void (*input_tool)(void);
 
     /* --------------------------------------------------- */
     /* 初始設定：載入檔案、引用文章、設定編輯模式          */
@@ -2044,6 +2043,7 @@ vedit(
 #ifdef  HAVE_INPUT_TOOLS
                 if (cc == VE_INPUTOOL)
                 {
+                    DL_HOTSWAP_SCOPE void (*input_tool)(void) = NULL;
                     if (!input_tool)
                     {
                         input_tool = DL_NAME_GET("ascii.so", input_tools);

maple/mail.c

@@ -2764,7 +2764,7 @@ static int
 mbox_gem(
     XO *xo)
 {
-    static void (*mgp)(void);
+    DL_HOTSWAP_SCOPE void (*mgp)(void) = NULL;
     if (!HAS_PERM(PERM_MBOX))
         return XO_NONE;
     if (!mgp)

maple/menu.c

@@ -1389,8 +1389,10 @@ domenu(
                     mitem.func = (int (*)(void)) DL_GET(mitem.dlfunc);
                     if (!mitem.func) break;
                     mmode = -mmode;
+  #ifndef DL_HOTSWAP
                     mptr->item = mitem;
                     mptr->umode = mmode;
+  #endif
                 }
 #endif
                 utmp_mode(mmode /* = mptr->umode*/);

maple/popupmenu.c

@@ -67,8 +67,10 @@ do_cmd(MENU *mptr, XO *xo, int x, int y)
         if (!mitem.xofunc)
             return 0;
         mmode = -mmode;
+  #ifndef DL_HOTSWAP
         mptr->item = mitem;
         mptr->umode = mmode;
+  #endif
     }
 #endif
 
@@ -84,8 +86,10 @@ do_cmd(MENU *mptr, XO *xo, int x, int y)
                 scr_free(&old_screen);
                 return 0;
             }
+  #ifndef DL_HOTSWAP
             mptr->item = mitem;
             mptr->umode = POPUP_FUN;
+  #endif
             mode = (*mitem.func) ();
             break;
 #endif

maple/talk.c

@@ -22,12 +22,6 @@ typedef struct
     char ship[46];
 }  PAL_SHIP;
 
-#ifdef  HAVE_PIP_FIGHT
-    void (*p)(void);
-#endif
-
-
-
 static int pal_count;
 static int *pal_pool;
 static int bmw_modetype;
@@ -2953,6 +2947,7 @@ talk_page(
 #ifdef  HAVE_PIP_FIGHT
     else if (ans == 'c')
     {
+        DL_HOTSWAP_SCOPE void (*p)(void) = NULL;
         if (!p)
             p = DL_NAME_GET("pip.so", pip_vf_fight);
         if (p)
@@ -4366,6 +4361,7 @@ talk_rqst(void)
 #ifdef  HAVE_PIP_FIGHT
             else if (ans == 'c')
             {
+                DL_HOTSWAP_SCOPE void (*p)(void) = NULL;
                 if (!p)
                     p = DL_NAME_GET("pip.so", pip_vf_fight);
                 strcpy(cutmp->mateid, up->userid);

maple/xover.c

@@ -1682,11 +1682,16 @@ xover(
                     if (p)
                     {
   #ifdef HAVE_HASH_KEYFUNCLIST
+    #ifdef DL_HOTSWAP
                         xcmd->erase(num);
                         cb = xcmd->insert({cmd, {p}}).first;
+    #endif
   #else
+    #ifdef DL_HOTSWAP
                         cb->second.func = p;
-                        pos = cb->first = cmd;
+                        cb->first = cmd;
+    #endif
+                        pos = cmd;
   #endif
                     }
                     else
@@ -1929,7 +1934,7 @@ xover(
 #ifdef  HAVE_MAILGEM
                 else if (cmd == 'G' && HAS_PERM(PERM_MBOX))
                 {
-                    static int (*mgp)(XO *xo);
+                    DL_HOTSWAP_SCOPE int (*mgp)(XO *xo) = NULL;
                     if (!mgp)
                     {
                         mgp = DL_NAME_GET("mailgem.so", mailgem_gather);

sample/dreambbs.conf

@@ -23,6 +23,11 @@
     "\033[1;32m�� Origin: \033[35m�ڦR�毸 \033[33m<news.clam.ml>  \033[31m�� From:\033[36m %-34.34s \033[m\n"
 
 
+/* �}�� DSO �Ҳժ� hot swapping  Enable hot swapping for DSO modules */
+/* �}�ҫᤣ�����s�n�J�Y�i�M�� DSO �Ҳժ���s */
+/* Re-login is not required to reload DSO modules when enabled */
+//#define DL_HOTSWAP
+
 /* �}�� pmore �\Ū������ */
 //#define M3_USE_PMORE            /* piaip's more 2007+ */
 

so/xyz.c

@@ -47,7 +47,9 @@ x_siteinfo(void)
     prints("\x1b[1;33mInternet Technology Lab\x1b[37m, Institute of CCE, National Cheng Kung University.\x1b[m\n");
     prints("\n");
 #ifdef Modules
-    prints("Modules & Plug-in: \x1b[m\n\n");
+#define CHECK_CONF(conf)  ((bool)(module_flags & (MODULE_ ## conf)))
+    prints("Modules & Plug-in: %s\x1b[m\n\n",
+        CHECK_CONF(DL_HOTSWAP) ? "[\x1b[1;32mHotswap enabled\x1b[m]" : "[\x1b[1;31mHotswap disabled\x1b[m]");
 
 //模組化的放在這邊
 #define ONLINE_STR  "\x1b[1;32monline \x1b[m"