openenvutils/commandshell/shell/src/module.c
changeset 0 2e3d3ce01487
child 1 0fdb7f6b0309
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/openenvutils/commandshell/shell/src/module.c	Tue Feb 02 10:12:00 2010 +0200
@@ -0,0 +1,2227 @@
+// module.c - deal with dynamic modules
+//
+// © Portions Copyright (c) Symbian Software Ltd 2007. All rights reserved.
+//
+/*
+ * This file is part of zsh, the Z shell.
+ *
+ * Copyright (c) 1996-1997 Zoltán Hidvégi
+ * All rights reserved.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and to distribute modified versions of this software for any
+ * purpose, provided that the above copyright notice and the following
+ * two paragraphs appear in all copies of this software.
+ *
+ * In no event shall Zoltán Hidvégi or the Zsh Development Group be liable
+ * to any party for direct, indirect, special, incidental, or consequential
+ * damages arising out of the use of this software and its documentation,
+ * even if Zoltán Hidvégi and the Zsh Development Group have been advised of
+ * the possibility of such damage.
+ *
+ * Zoltán Hidvégi and the Zsh Development Group specifically disclaim any
+ * warranties, including, but not limited to, the implied warranties of
+ * merchantability and fitness for a particular purpose.  The software
+ * provided hereunder is on an "as is" basis, and Zoltán Hidvégi and the
+ * Zsh Development Group have no obligation to provide maintenance,
+ * support, updates, enhancements, or modifications.
+ *
+ */
+#include "zsh.mdh"
+#include "module.pro"
+
+#ifdef __SYMBIAN32__
+#ifdef __WINSCW__
+#pragma warn_unusedarg off
+#pragma warn_possunwant off
+#endif//__WINSCW__
+#endif//__SYMBIAN32__
+
+/* List of linked-in modules. */
+
+/**/
+LinkList linkedmodules;
+
+
+/* The `zsh/main' module contains all the base code that can't actually be *
+ * built as a separate module.  It is initialised by main(), so there's    *
+ * nothing for the boot function to do.                                    */
+
+/**/
+int
+setup_(UNUSED(Module m))
+{
+    return 0;
+}
+
+/**/
+int
+boot_(UNUSED(Module m))
+{
+    return 0;
+}
+
+/**/
+int
+cleanup_(UNUSED(Module m))
+{
+    return 0;
+}
+
+/**/
+int
+finish_(UNUSED(Module m))
+{
+    return 0;
+}
+
+/* This registers a builtin module.                                   */
+
+/**/
+void
+register_module(char *n, Module_func setup, Module_func boot,
+		Module_func cleanup, Module_func finish)
+{
+    Linkedmod m;
+
+    m = (Linkedmod) zalloc(sizeof(*m));
+
+    m->name = ztrdup(n);
+    m->setup = setup;
+    m->boot = boot;
+    m->cleanup = cleanup;
+    m->finish = finish;
+
+    zaddlinknode(linkedmodules, m);
+}
+
+/* Print an alias. */
+
+/**/
+static void
+printmodalias(Module m, Options ops)
+{
+    if (OPT_ISSET(ops,'L')) {
+	printf("zmodload -A ");
+	if (m->nam[0] == '-')
+	    fputs("-- ", stdout);
+	quotedzputs(m->nam, stdout);
+	putchar('=');
+	quotedzputs(m->u.alias, stdout);
+    } else {
+	nicezputs(m->nam, stdout);
+	fputs(" -> ", stdout);
+	nicezputs(m->u.alias, stdout);
+    }
+    putchar('\n');
+}
+
+/* Check if a module is linked in. */
+
+/**/
+Linkedmod
+module_linked(char const *name)
+{
+    LinkNode node;
+
+    for (node = firstnode(linkedmodules); node; incnode(node))
+	if (!strcmp(((Linkedmod) getdata(node))->name, name))
+	    return (Linkedmod) getdata(node);
+
+    return NULL;
+}
+
+/* addbuiltin() can be used to add a new builtin.  It returns zero on *
+ * success, 1 on failure.  The only possible type of failure is that  *
+ * a builtin with the specified name already exists.  An autoloaded   *
+ * builtin can be replaced using this function.                       */
+
+/**/
+int
+addbuiltin(Builtin b)
+{
+    Builtin bn = (Builtin) builtintab->getnode2(builtintab, b->nam);
+    if (bn && (bn->flags & BINF_ADDED))
+	return 1;
+    if (bn)
+	builtintab->freenode(builtintab->removenode(builtintab, b->nam));
+    builtintab->addnode(builtintab, b->nam, b);
+    return 0;
+}
+
+/* Add multiple builtins.  binl points to a table of `size' builtin      *
+ * structures.  Those for which (.flags & BINF_ADDED) is false are to be *
+ * added; that flag is set if they succeed.  If any fail, an error       *
+ * message is printed, using nam as the leading name.  Returns 1 if all  *
+ * additions succeed, 2 if some succeed and some fail, and 0 if all (and *
+ * at least 1) fail.  The usual usage in a boot_*() function would be    *
+ *  return !addbuiltins(m->nam, bintab, sizeof(bintab)/sizeof(*bintab)); */
+
+/**/
+mod_export int
+addbuiltins(char const *nam, Builtin binl, int size)
+{
+    int hads = 0, hadf = 0, n;
+
+    for(n = 0; n < size; n++) {
+	Builtin b = &binl[n];
+	if(b->flags & BINF_ADDED)
+	    continue;
+	if(addbuiltin(b)) {
+	    zwarnnam(nam, "name clash when adding builtin `%s'", b->nam, 0);
+	    hadf = 1;
+	} else {
+	    b->flags |= BINF_ADDED;
+	    hads = 2;
+	}
+    }
+    return hadf ? hads : 1;
+}
+
+/* The list of function wrappers defined. */
+
+/**/
+FuncWrap wrappers;
+
+/* This adds a definition for a wrapper. Return value is one in case of *
+ * error and zero if all went fine. */
+
+/**/
+mod_export int
+addwrapper(Module m, FuncWrap w)
+{
+    FuncWrap p, q;
+
+    /*
+     * We can't add a wrapper to an alias, since it's supposed
+     * to behave identically to the resolved module.  This shouldn't
+     * happen since we usually add wrappers when a real module is
+     * loaded.
+     */
+    if (m->flags & MOD_ALIAS)
+	return 1;
+
+    if (w->flags & WRAPF_ADDED)
+	return 1;
+    for (p = wrappers, q = NULL; p; q = p, p = p->next);
+    if (q)
+	q->next = w;
+    else
+	wrappers = w;
+    w->next = NULL;
+    w->flags |= WRAPF_ADDED;
+    w->module = m;
+
+    return 0;
+}
+
+/* $module_path ($MODULE_PATH) */
+
+/**/
+char **module_path;
+
+/* List of modules */
+
+/**/
+mod_export LinkList modules;
+
+/* Define an autoloadable builtin.  It returns 0 on success, or 1 on *
+ * failure.  The only possible cause of failure is that a builtin    *
+ * with the specified name already exists.                           */
+
+/**/
+int
+add_autobin(char *nam, char *module)
+{
+    Builtin bn = zshcalloc(sizeof(*bn));
+    bn->nam = ztrdup(nam);
+    bn->optstr = ztrdup(module);
+    return addbuiltin(bn);
+}
+
+/* Remove the builtin added previously by addbuiltin().  Returns *
+ * zero on succes and -1 if there is no builtin with that name.  */
+
+/**/
+int
+deletebuiltin(char *nam)
+{
+    Builtin bn;
+
+    bn = (Builtin) builtintab->removenode(builtintab, nam);
+    if (!bn)
+	return -1;
+    builtintab->freenode((HashNode)bn);
+    return 0;
+}
+
+/* Delete multiple builtins.  binl points to a table of `size' builtin  *
+ * structures.  Those for which (.flags & BINF_ADDED) is true are to be *
+ * deleted; that flag is cleared.  If any fail, an error message is     *
+ * printed, using nam as the leading name.  Returns 1 if all deletions  *
+ * succeed, 2 if some succeed and some fail, and 0 if all (and at least *
+ * 1) fail.  In normal use, from a cleanup_*() function, this return    *
+ * value would be ignored -- the only cause of failure would be that a  *
+ * wayward module had deleted our builtin without telling us.           */
+
+/**/
+mod_export int
+deletebuiltins(char const *nam, Builtin binl, int size)
+{
+    int hads = 0, hadf = 0, n;
+
+    for(n = 0; n < size; n++) {
+	Builtin b = &binl[n];
+	if(!(b->flags & BINF_ADDED))
+	    continue;
+	if(deletebuiltin(b->nam)) {
+	    zwarnnam(nam, "builtin `%s' already deleted", b->nam, 0);
+	    hadf = 1;
+	} else
+	    hads = 2;
+	b->flags &= ~BINF_ADDED;
+    }
+    return hadf ? hads : 1;
+}
+
+/* This removes the given wrapper definition from the list. Returned is *
+ * one in case of error and zero otherwise. */
+
+/**/
+mod_export int
+deletewrapper(Module m, FuncWrap w)
+{
+    FuncWrap p, q;
+
+    if (m->flags & MOD_ALIAS)
+	return 1;
+
+    if (w->flags & WRAPF_ADDED) {
+	for (p = wrappers, q = NULL; p && p != w; q = p, p = p->next);
+
+	if (p) {
+	    if (q)
+		q->next = p->next;
+	    else
+		wrappers = p->next;
+	    p->flags &= ~WRAPF_ADDED;
+
+	    return 0;
+	}
+    }
+    return 1;
+}
+
+/**/
+#ifdef DYNAMIC
+
+/**/
+#ifdef AIXDYNAMIC
+
+#include <sys/ldr.h>
+
+static char *dlerrstr[256];
+
+static void *
+load_and_bind(const char *fn)
+{
+    void *ret = (void *) load((char *) fn, L_NOAUTODEFER, NULL);
+
+    if (ret) {
+	LinkNode node;
+	int err = loadbind(0, (void *) addbuiltin, ret);
+	for (node = firstnode(modules); !err && node; incnode(node)) {
+	    Module m = (Module) getdata(node);
+	    if (!(m->flags & MOD_ALIAS) &&
+		m->u.handle && !(m->flags & MOD_LINKED))
+		err |= loadbind(0, m->u.handle, ret);
+	}
+
+	if (err) {
+	    loadquery(L_GETMESSAGES, dlerrstr, sizeof(dlerrstr));
+	    unload(ret);
+	    ret = NULL;
+	}
+    } else
+	loadquery(L_GETMESSAGES, dlerrstr, sizeof(dlerrstr));
+
+    return ret;
+}
+
+#define dlopen(X,Y) load_and_bind(X)
+#define dlclose(X)  unload(X)
+#define dlerror()   (dlerrstr[0])
+
+/**/
+#else
+
+#ifdef HAVE_DLFCN_H
+# if defined(HAVE_DL_H) && defined(HPUXDYNAMIC)
+#  include <dl.h>
+# else
+#  include <dlfcn.h>
+# endif
+#else
+# ifdef HAVE_DL_H
+#  include <dl.h>
+#  define RTLD_LAZY BIND_DEFERRED
+#  define RTLD_GLOBAL DYNAMIC_PATH
+# else
+#  include <sys/types.h>
+#  include <nlist.h>
+#  include <link.h>
+# endif
+#endif
+
+/**/
+#ifdef HPUXDYNAMIC
+# define dlopen(file,mode) (void *)shl_load((file), (mode), (long) 0)
+# define dlclose(handle) shl_unload((shl_t)(handle))
+
+static
+void *
+hpux_dlsym(void *handle, char *name)
+{
+    void *sym_addr;
+    if (!shl_findsym((shl_t *)&handle, name, TYPE_UNDEFINED, &sym_addr))
+	return sym_addr;
+    return NULL;
+}
+
+# define dlsym(handle,name) hpux_dlsym(handle,name)
+# define dlerror() 0
+#else
+# ifndef HAVE_DLCLOSE
+#  define dlclose(X) ((X), 0)
+# endif
+/**/
+#endif
+
+#ifdef DLSYM_NEEDS_UNDERSCORE
+# define STR_SETUP     "_setup_"
+# define STR_BOOT      "_boot_"
+# define STR_CLEANUP   "_cleanup_"
+# define STR_FINISH    "_finish_"
+#else /* !DLSYM_NEEDS_UNDERSCORE */
+# define STR_SETUP     "setup_"
+# define STR_BOOT      "boot_"
+# define STR_CLEANUP   "cleanup_"
+# define STR_FINISH    "finish_"
+#endif /* !DLSYM_NEEDS_UNDERSCORE */
+
+/**/
+#endif /* !AIXDYNAMIC */
+
+#ifndef RTLD_LAZY
+# define RTLD_LAZY 1
+#endif
+#ifndef RTLD_GLOBAL
+# define RTLD_GLOBAL 0
+#endif
+
+/**/
+static void *
+try_load_module(char const *name)
+{
+    char buf[PATH_MAX + 1];
+    char **pp;
+    void *ret = NULL;
+    int l;
+
+    l = 1 + strlen(name) + 1 + strlen(DL_EXT);
+    for (pp = module_path; !ret && *pp; pp++) {
+	if (l + (**pp ? strlen(*pp) : 1) > PATH_MAX)
+	    continue;
+	sprintf(buf, "%s/%s.%s", **pp ? *pp : ".", name, DL_EXT);
+	ret = dlopen(unmeta(buf), RTLD_LAZY | RTLD_GLOBAL);
+    }
+
+    return ret;
+}
+
+/**/
+static void *
+do_load_module(char const *name)
+{
+    void *ret;
+
+    ret = try_load_module(name);
+    if (!ret) {
+	int waserr = errflag;
+	zerr("failed to load module: %s", name, 0);
+	errflag = waserr;
+    }
+    return ret;
+}
+
+/**/
+#else /* !DYNAMIC */
+
+/**/
+static void *
+do_load_module(char const *name)
+{
+    int waserr = errflag;
+
+    zerr("failed to load module: %s", name, 0);
+    errflag = waserr;
+
+    return NULL;
+}
+
+/**/
+#endif /* !DYNAMIC */
+
+/*
+ * Find a module in the list.
+ * If aliasp is non-zero, resolve any aliases to the underlying module.
+ * If namep is set, this is set to point to the last alias value resolved,
+ *   even if that module was not loaded. or the module name if no aliases.
+ *   Hence this is always the physical module to load in a chain of aliases.
+ * Return NULL if the module named is not stored as a structure, or if we were
+ * resolving aliases and the final module named is not stored as a
+ * structure.
+ *
+ * TODO: now we have aliases, there may be some merit in using a hash
+ * table instead of a linked list.
+ */
+/**/
+static LinkNode
+find_module(const char *name, int aliasp, const char **namep)
+{
+    Module m;
+    LinkNode node;
+
+    for (node = firstnode(modules); node; incnode(node)) {
+	m = (Module) getdata(node);
+	if (!strcmp(m->nam, name)) {
+	    if (aliasp && (m->flags & MOD_ALIAS)) {
+		if (namep)
+		    *namep = m->u.alias;
+		return find_module(m->u.alias, 1, namep);
+	    }
+	    if (namep)
+		*namep = m->nam;
+	    return node;
+	}
+    }
+    return NULL;
+}
+
+/*
+ * Unlink and free a module node from the linked list.
+ */
+
+/**/
+static void
+delete_module(LinkNode node)
+{
+    Module m = (Module) remnode(modules, node);
+
+    if (m->flags & MOD_ALIAS)
+	zsfree(m->u.alias);
+    zsfree(m->nam);
+    if (m->deps)
+	freelinklist(m->deps, freestr);
+    zfree(m, sizeof(*m));
+}
+
+/**/
+mod_export int
+module_loaded(const char *name)
+{
+    LinkNode node;
+    Module m;
+
+    return ((node = find_module(name, 1, NULL)) &&
+	    (m = ((Module) getdata(node)))->u.handle &&
+	    !(m->flags & MOD_UNLOAD));
+}
+
+/*
+ * Setup and cleanup functions:  we don't search for aliases here,
+ * since they should have been resolved before we try to load or unload
+ * the module.
+ */
+
+/**/
+#ifdef DYNAMIC
+
+/**/
+#ifdef AIXDYNAMIC
+
+/**/
+static int
+dyn_setup_module(Module m)
+{
+    return ((int (*)_((int,Module))) m->u.handle)(0, m);
+}
+
+/**/
+static int
+dyn_boot_module(Module m)
+{
+    return ((int (*)_((int,Module))) m->u.handle)(1, m);
+}
+
+/**/
+static int
+dyn_cleanup_module(Module m)
+{
+    return ((int (*)_((int,Module))) m->u.handle)(2, m);
+}
+
+/**/
+static int
+dyn_finish_module(Module m)
+{
+    return ((int (*)_((int,Module))) m->u.handle)(3, m);
+}
+
+/**/
+#else
+
+static Module_func
+module_func(Module m, char *name)
+{
+#ifdef DYNAMIC_NAME_CLASH_OK
+    return (Module_func) dlsym(m->u.handle, name);
+#else /* !DYNAMIC_NAME_CLASH_OK */
+    VARARR(char, buf, strlen(name) + strlen(m->nam)*2 + 1);
+    char const *p;
+    char *q;
+    strcpy(buf, name);
+    q = strchr(buf, 0);
+    for(p = m->nam; *p; p++) {
+	if(*p == '/') {
+	    *q++ = 'Q';
+	    *q++ = 's';
+	} else if(*p == '_') {
+	    *q++ = 'Q';
+	    *q++ = 'u';
+	} else if(*p == 'Q') {
+	    *q++ = 'Q';
+	    *q++ = 'q';
+	} else
+	    *q++ = *p;
+    }
+    *q = 0;
+    return (Module_func) dlsym(m->u.handle, buf);
+#endif /* !DYNAMIC_NAME_CLASH_OK */
+}
+
+/**/
+static int
+dyn_setup_module(Module m)
+{
+    Module_func fn = module_func(m, STR_SETUP);
+
+    if (fn)
+	return fn(m);
+    zwarnnam(m->nam, "no setup function", NULL, 0);
+    return 1;
+}
+
+/**/
+static int
+dyn_boot_module(Module m)
+{
+    Module_func fn = module_func(m, STR_BOOT);
+
+    if(fn)
+	return fn(m);
+    zwarnnam(m->nam, "no boot function", NULL, 0);
+    return 1;
+}
+
+/**/
+static int
+dyn_cleanup_module(Module m)
+{
+    Module_func fn = module_func(m, STR_CLEANUP);
+
+    if(fn)
+	return fn(m);
+    zwarnnam(m->nam, "no cleanup function", NULL, 0);
+    return 1;
+}
+
+/* Note that this function does more than just calling finish_foo(), *
+ * it really unloads the module. */
+
+/**/
+static int
+dyn_finish_module(Module m)
+{
+    Module_func fn = module_func(m, STR_FINISH);
+    int r;
+
+    if (fn)
+	r = fn(m);
+    else {
+	zwarnnam(m->nam, "no finish function", NULL, 0);
+	r = 1;
+    }
+    dlclose(m->u.handle);
+    return r;
+}
+
+/**/
+#endif /* !AIXDYNAMIC */
+
+/**/
+static int
+setup_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ?
+	    (m->u.linked->setup)(m) : dyn_setup_module(m));
+}
+
+/**/
+static int
+boot_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ?
+	    (m->u.linked->boot)(m) : dyn_boot_module(m));
+}
+
+/**/
+static int
+cleanup_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ?
+	    (m->u.linked->cleanup)(m) : dyn_cleanup_module(m));
+}
+
+/**/
+static int
+finish_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ?
+	    (m->u.linked->finish)(m) : dyn_finish_module(m));
+}
+
+/**/
+#else /* !DYNAMIC */
+
+/**/
+static int
+setup_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ? (m->u.linked->setup)(m) : 1);
+}
+
+/**/
+static int
+boot_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ? (m->u.linked->boot)(m) : 1);
+}
+
+/**/
+static int
+cleanup_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ? (m->u.linked->cleanup)(m) : 1);
+}
+
+/**/
+static int
+finish_module(Module m)
+{
+    return ((m->flags & MOD_LINKED) ? (m->u.linked->finish)(m) : 1);
+}
+
+/**/
+#endif /* !DYNAMIC */
+
+/**/
+static int
+modname_ok(char const *p)
+{
+    do {
+	if(*p != '_' && !ialnum(*p))
+	    return 0;
+	do {
+	    p++;
+	} while(*p == '_' || ialnum(*p));
+	if(!*p)
+	    return 1;
+    } while(*p++ == '/');
+    return 0;
+}
+
+/**/
+mod_export int
+load_module(char const *name)
+{
+    Module m;
+    void *handle = NULL;
+    Linkedmod linked;
+    LinkNode node, n;
+    int set;
+
+    if (!modname_ok(name)) {
+	zerr("invalid module name `%s'", name, 0);
+	return 0;
+    }
+    /*
+     * The following function call may alter name to the final name in a
+     * chain of aliases.  This makes sure the actual module loaded
+     * is the right one.
+     */
+    queue_signals();
+    if (!(node = find_module(name, 1, &name))) {
+	if (!(linked = module_linked(name)) &&
+	    !(handle = do_load_module(name))) {
+	    unqueue_signals();
+	    return 0;
+	}
+	m = zshcalloc(sizeof(*m));
+	m->nam = ztrdup(name);
+	if (handle) {
+	    m->u.handle = handle;
+	    m->flags |= MOD_SETUP;
+	} else {
+	    m->u.linked = linked;
+	    m->flags |= MOD_SETUP | MOD_LINKED;
+	}
+	node = zaddlinknode(modules, m);
+
+	if ((set = setup_module(m)) || boot_module(m)) {
+	    if (!set)
+		finish_module(m);
+	    delete_module(node);
+	    unqueue_signals();
+	    return 0;
+	}
+	m->flags |= MOD_INIT_S | MOD_INIT_B;
+	m->flags &= ~MOD_SETUP;
+	unqueue_signals();
+	return 1;
+    } 
+    m = (Module) getdata(node);
+    if (m->flags & MOD_SETUP) {
+	unqueue_signals();
+	return 1;
+    }
+    if (m->flags & MOD_UNLOAD)
+	m->flags &= ~MOD_UNLOAD;
+    else if ((m->flags & MOD_LINKED) ? m->u.linked : m->u.handle) {
+	unqueue_signals();
+	return 1;
+    }
+    if (m->flags & MOD_BUSY) {
+	zerr("circular dependencies for module %s", name, 0);
+	return 0;
+    }
+    m->flags |= MOD_BUSY;
+    if (m->deps)
+	for (n = firstnode(m->deps); n; incnode(n))
+	    if (!load_module((char *) getdata(n))) {
+		m->flags &= ~MOD_BUSY;
+		unqueue_signals();
+		return 0;
+	    }
+    m->flags &= ~MOD_BUSY;
+    if (!m->u.handle) {
+	handle = NULL;
+	if (!(linked = module_linked(name)) &&
+	    !(handle = do_load_module(name))) {
+	    unqueue_signals();
+	    return 0;
+	}
+	if (handle) {
+	    m->u.handle = handle;
+	    m->flags |= MOD_SETUP;
+	} else {
+	    m->u.linked = linked;
+	    m->flags |= MOD_SETUP | MOD_LINKED;
+	}
+	if (setup_module(m)) {
+	    if (handle)
+		m->u.handle = NULL;
+	    else
+		m->u.linked = NULL;
+	    m->flags &= ~MOD_SETUP;
+	    unqueue_signals();
+	    return 0;
+	}
+	m->flags |= MOD_INIT_S;
+    }
+    m->flags |= MOD_SETUP;
+    if (boot_module(m)) {
+	finish_module(m);
+	if (m->flags & MOD_LINKED)
+	    m->u.linked = NULL;
+	else
+	    m->u.handle = NULL;
+	m->flags &= ~MOD_SETUP;
+	unqueue_signals();
+	return 0;
+    }
+    m->flags |= MOD_INIT_B;
+    m->flags &= ~MOD_SETUP;
+    unqueue_signals();
+    return 1;
+}
+
+/* This ensures that the module with the name given as the second argument
+ * is loaded.
+ * The third argument should be non-zero if the function should complain
+ * about trying to load a module with a full path name in restricted mode.
+ * The last argument should be non-zero if this function should signal an
+ * error if the module is already loaded.
+ * The return value is non-zero if the module was found or loaded. */
+
+/**/
+mod_export int
+require_module(char *nam, const char *module, UNUSED(int res), int test)
+{
+    Module m = NULL;
+    LinkNode node;
+    int ret = 1;
+
+    /* Resolve aliases and actual loadable module as for load_module */
+    queue_signals();
+    node = find_module(module, 1, &module);
+    if (node && (m = ((Module) getdata(node)))->u.handle &&
+	!(m->flags & MOD_UNLOAD)) {
+	if (test) {
+	    unqueue_signals();
+	    zwarnnam(nam, "module %s already loaded.", module, 0);
+	    return 0;
+	}
+    } else
+	ret = load_module(module);
+    unqueue_signals();
+
+    return ret;
+}
+
+/**/
+void
+add_dep(const char *name, char *from)
+{
+    LinkNode node;
+    Module m;
+
+    /*
+     * If we were passed an alias, we must resolve it to a final
+     * module name (and maybe add the corresponding struct), since otherwise
+     * we would need to check all modules to see if they happen
+     * to be aliased to the same thing to implement dependencies properly.
+     *
+     * This should mean that an attempt to add an alias which would
+     * have the same name as a module which has dependencies is correctly
+     * rejected, because then the module named already exists as a non-alias.
+     * Better make sure.  (There's no problem making a an alias which
+     * *points* to a module with dependencies, of course.)
+     */
+    if (!(node = find_module(name, 1, &name))) {
+	m = zshcalloc(sizeof(*m));
+	m->nam = ztrdup(name);
+	zaddlinknode(modules, m);
+    } else
+	m = (Module) getdata(node);
+    if (!m->deps)
+	m->deps = znewlinklist();
+    for (node = firstnode(m->deps);
+	 node && strcmp((char *) getdata(node), from);
+	 incnode(node));
+    if (!node)
+	zaddlinknode(m->deps, ztrdup(from));
+}
+
+/**/
+static void
+autoloadscan(HashNode hn, int printflags)
+{
+    Builtin bn = (Builtin) hn;
+
+    if(bn->flags & BINF_ADDED)
+	return;
+    if(printflags & PRINT_LIST) {
+	fputs("zmodload -ab ", stdout);
+	if(bn->optstr[0] == '-')
+	    fputs("-- ", stdout);
+	quotedzputs(bn->optstr, stdout);
+	if(strcmp(bn->nam, bn->optstr)) {
+	    putchar(' ');
+	    quotedzputs(bn->nam, stdout);
+	}
+    } else {
+	nicezputs(bn->nam, stdout);
+	if(strcmp(bn->nam, bn->optstr)) {
+	    fputs(" (", stdout);
+	    nicezputs(bn->optstr, stdout);
+	    putchar(')');
+	}
+    }
+    putchar('\n');
+}
+
+#ifndef __SYMBIAN32__
+/**/
+int
+bin_zmodload(char *nam, char **args, Options ops, UNUSED(int func))
+{
+    int ops_bcpf = OPT_ISSET(ops,'b') || OPT_ISSET(ops,'c') || 
+	OPT_ISSET(ops,'p') || OPT_ISSET(ops,'f');
+    int ops_au = OPT_ISSET(ops,'a') || OPT_ISSET(ops,'u');
+    int ret = 1;
+
+    if (ops_bcpf && !ops_au) {
+	zwarnnam(nam, "-b, -c, -f, and -p must be combined with -a or -u",
+		 NULL, 0);
+	return 1;
+    }
+    if (OPT_ISSET(ops,'A') || OPT_ISSET(ops,'R')) {
+	if (ops_bcpf || ops_au || OPT_ISSET(ops,'d') || 
+	    (OPT_ISSET(ops,'R') && OPT_ISSET(ops,'e'))) {
+	    zwarnnam(nam, "illegal flags combined with -A or -R", NULL, 0);
+	    return 1;
+	}
+	if (!OPT_ISSET(ops,'e'))
+	    return bin_zmodload_alias(nam, args, ops);
+    }
+    if (OPT_ISSET(ops,'d') && OPT_ISSET(ops,'a')) {
+	zwarnnam(nam, "-d cannot be combined with -a", NULL, 0);
+	return 1;
+    }
+    if (OPT_ISSET(ops,'u') && !*args) {
+	zwarnnam(nam, "what do you want to unload?", NULL, 0);
+	return 1;
+    }
+    if (OPT_ISSET(ops,'e') && (OPT_ISSET(ops,'I') || OPT_ISSET(ops,'L') || 
+			       OPT_ISSET(ops,'a') || OPT_ISSET(ops,'d') ||
+			       OPT_ISSET(ops,'i') || OPT_ISSET(ops,'u'))) {
+	zwarnnam(nam, "-e cannot be combined with other options", NULL, 0);
+	return 1;
+    }
+    queue_signals();
+    if (OPT_ISSET(ops,'e'))
+	ret = bin_zmodload_exist(nam, args, ops);
+    else if (OPT_ISSET(ops,'d'))
+	ret = bin_zmodload_dep(nam, args, ops);
+    else if ((OPT_ISSET(ops,'a') || OPT_ISSET(ops,'b')) && 
+	     !(OPT_ISSET(ops,'c') || OPT_ISSET(ops,'p') || OPT_ISSET(ops,'f')))
+	ret = bin_zmodload_auto(nam, args, ops);
+    else if (OPT_ISSET(ops,'c') && !(OPT_ISSET(ops,'b') || OPT_ISSET(ops,'p')))
+	ret = bin_zmodload_cond(nam, args, ops);
+    else if (OPT_ISSET(ops,'f') && !(OPT_ISSET(ops,'b') || OPT_ISSET(ops,'p')))
+	ret = bin_zmodload_math(nam, args, ops);
+    else if (OPT_ISSET(ops,'p') && !(OPT_ISSET(ops,'b') || OPT_ISSET(ops,'c')))
+	ret = bin_zmodload_param(nam, args, ops);
+    else if (!(OPT_ISSET(ops,'a') || OPT_ISSET(ops,'b') || 
+	       OPT_ISSET(ops,'c') || OPT_ISSET(ops,'p')))
+	ret = bin_zmodload_load(nam, args, ops);
+    else
+	zwarnnam(nam, "use only one of -b, -c, or -p", NULL, 0);
+    unqueue_signals();
+
+    return ret;
+}
+#endif //#ifndef __SYMBIAN32__
+
+/**/
+static int
+bin_zmodload_alias(char *nam, char **args, Options ops)
+{
+    /*
+     * TODO: while it would be too nasty to have aliases, as opposed
+     * to real loadable modules, with dependencies --- just what would
+     * we need to load when, exactly? --- there is in principle no objection
+     * to making it possible to force an alias onto an existing unloaded
+     * module which has dependencies.  This would simply transfer
+     * the dependencies down the line to the aliased-to module name.
+     * This is actually useful, since then you can alias zsh/zle=mytestzle
+     * to load another version of zle.  But then what happens when the
+     * alias is removed?  Do you transfer the dependencies back? And
+     * suppose other names are aliased to the same file?  It might be
+     * kettle of fish best left unwormed.
+     */
+    LinkNode node;
+    Module m;
+    int ret = 0;
+
+    if (!*args) {
+	if (OPT_ISSET(ops,'R')) {
+	    zwarnnam(nam, "no module alias to remove", NULL, 0);
+	    return 1;
+	}
+	for (node = firstnode(modules); node; incnode(node)) {
+	    m = (Module) getdata(node);
+	    if (m->flags & MOD_ALIAS)
+		printmodalias(m, ops);
+	}
+	return 0;
+    }
+
+    for (; !ret && *args; args++) {
+	char *eqpos = strchr(*args, '=');
+	char *aliasname = eqpos ? eqpos+1 : NULL;
+	if (eqpos)
+	    *eqpos = '\0';
+	if (!modname_ok(*args)) {
+	    zwarnnam(nam, "invalid module name `%s'", *args, 0);
+	    return 1;
+	}
+	if (OPT_ISSET(ops,'R')) {
+	    if (aliasname) {
+		zwarnnam(nam, "bad syntax for removing module alias: %s",
+			 *args, 0);
+		return 1;
+	    }
+	    node = find_module(*args, 0, NULL);
+	    if (node) {
+		m = (Module) getdata(node);
+		if (!(m->flags & MOD_ALIAS)) {
+		    zwarnnam(nam, "module is not an alias: %s", *args, 0);
+		    ret = 1;
+		    break;
+		}
+		delete_module(node);
+	    } else {
+		zwarnnam(nam, "no such module alias: %s", *args, 0);
+		return 1;
+	    }
+	} else {
+	    if (aliasname) {
+		const char *mname = aliasname;
+		if (!modname_ok(aliasname)) {
+		    zwarnnam(nam, "invalid module name `%s'", aliasname, 0);
+		    return 1;
+		}
+		find_module(aliasname, 1, &mname);
+		if (!strcmp(mname, *args)) {
+		    zwarnnam(nam, "module alias would refer to itself: %s",
+			     *args, 0);
+		    return 1;
+		}
+		node = find_module(*args, 0, NULL);
+		if (node) {
+		    m = (Module) getdata(node);
+		    if (!(m->flags & MOD_ALIAS)) {
+			zwarnnam(nam, "module is not an alias: %s", *args, 0);
+			return 1;
+		    }
+		    zsfree(m->u.alias);
+		} else {
+		    m = (Module) zshcalloc(sizeof(*m));
+		    m->nam = ztrdup(*args);
+		    m->flags = MOD_ALIAS;
+		    zaddlinknode(modules, m);
+		}
+		m->u.alias = ztrdup(aliasname);
+	    } else {
+		if ((node = find_module(*args, 0, NULL))) {
+		    m = (Module) getdata(node);
+		    if (m->flags & MOD_ALIAS)
+			printmodalias(m, ops);
+		    else {
+			zwarnnam(nam, "module is not an alias: %s",
+				 *args, 0);
+			return 1;
+		    }
+		} else {
+		    zwarnnam(nam, "no such module alias: %s", *args, 0);
+		    return 1;
+		}
+	    }
+	}
+    }
+
+    return 0;
+}
+
+/**/
+static int
+bin_zmodload_exist(UNUSED(char *nam), char **args, Options ops)
+{
+    LinkNode node;
+    Module m;
+    char *modname;
+
+    if (!*args) {
+	for (node = firstnode(modules); node; incnode(node)) {
+	    m = (Module) getdata(node);
+	    modname = m->nam;
+	    if (m->flags & MOD_ALIAS) {
+		LinkNode node2;
+		if (OPT_ISSET(ops,'A') && 
+		    (node2 = find_module(m->u.alias, 1, NULL)))
+		    m = (Module) getdata(node2);
+		else
+		    continue;
+	    } 
+	    if (m->u.handle && !(m->flags & MOD_UNLOAD)) {
+		nicezputs(modname, stdout);
+		putchar('\n');
+	    }
+	}
+	return 0;
+    } else {
+	int ret = 0;
+
+	for (; !ret && *args; args++) {
+	    if (!(node = find_module(*args, 1, NULL))
+		|| !(m = (Module) getdata(node))->u.handle
+		|| (m->flags & MOD_UNLOAD))
+		ret = 1;
+	}
+	return ret;
+    }
+}
+
+/**/
+static int
+bin_zmodload_dep(UNUSED(char *nam), char **args, Options ops)
+{
+    LinkNode node;
+    Module m;
+    if (OPT_ISSET(ops,'u')) {
+	/* remove dependencies, which can't pertain to aliases */
+	const char *tnam = *args++;
+	node = find_module(tnam, 1, &tnam);
+	if (!node)
+	    return 0;
+	m = (Module) getdata(node);
+	if (*args && m->deps) {
+	    do {
+		LinkNode dnode;
+		for (dnode = firstnode(m->deps); dnode; incnode(dnode))
+		    if (!strcmp(*args, getdata(dnode))) {
+			zsfree(getdata(dnode));
+			remnode(m->deps, dnode);
+			break;
+		    }
+	    } while(*++args);
+	    if (empty(m->deps)) {
+		freelinklist(m->deps, freestr);
+		m->deps = NULL;
+	    }
+	} else {
+	    if (m->deps) {
+		freelinklist(m->deps, freestr);
+		m->deps = NULL;
+	    }
+	}
+	if (!m->deps && !m->u.handle)
+	    delete_module(node);
+	return 0;
+    } else if (!args[0] || !args[1]) {
+	/* list dependencies */
+	for (node = firstnode(modules); node; incnode(node)) {
+	    m = (Module) getdata(node);
+	    if (m->deps && (!args[0] || !strcmp(args[0], m->nam))) {
+		LinkNode n;
+		if (OPT_ISSET(ops,'L')) {
+		    printf("zmodload -d ");
+		    if(m->nam[0] == '-')
+			fputs("-- ", stdout);
+		    quotedzputs(m->nam, stdout);
+		} else {
+		    nicezputs(m->nam, stdout);
+		    putchar(':');
+		}
+		for (n = firstnode(m->deps); n; incnode(n)) {
+		    putchar(' ');
+		    if(OPT_ISSET(ops,'L'))
+			quotedzputs((char *) getdata(n), stdout);
+		    else
+			nicezputs((char *) getdata(n), stdout);
+		}
+		putchar('\n');
+	    }
+	}
+	return 0;
+    } else {
+	/* add dependencies */
+	int ret = 0;
+	char *tnam = *args++;
+
+	for (; *args; args++)
+	    add_dep(tnam, *args);
+	return ret;
+    }
+}
+
+/**/
+static int
+bin_zmodload_auto(char *nam, char **args, Options ops)
+{
+    int ret = 0;
+    if(OPT_ISSET(ops,'u')) {
+	/* remove autoloaded builtins */
+	for (; *args; args++) {
+	    Builtin bn = (Builtin) builtintab->getnode2(builtintab, *args);
+	    if (!bn) {
+		if(!OPT_ISSET(ops,'i')) {
+		    zwarnnam(nam, "%s: no such builtin", *args, 0);
+		    ret = 1;
+		}
+	    } else if (bn->flags & BINF_ADDED) {
+		zwarnnam(nam, "%s: builtin is already defined", *args, 0);
+		ret = 1;
+	    } else
+		deletebuiltin(*args);
+	}
+	return ret;
+    } else if(!*args) {
+	/* list autoloaded builtins */
+	scanhashtable(builtintab, 0, 0, 0,
+	    autoloadscan, OPT_ISSET(ops,'L') ? PRINT_LIST : 0);
+	return 0;
+    } else {
+	/* add autoloaded builtins */
+	char *modnam;
+	modnam = *args++;
+	do {
+	    char *bnam = *args ? *args++ : modnam;
+	    if (strchr(bnam, '/')) {
+		zwarnnam(nam, "%s: `/' is illegal in a builtin", bnam, 0);
+		ret = 1;
+	    } else if (add_autobin(bnam, modnam) && !OPT_ISSET(ops,'i')) {
+		zwarnnam(nam, "failed to add builtin %s", bnam, 0);
+		ret = 1;
+	    }
+	} while(*args);
+	return ret;
+    }
+}
+
+/**/
+static int
+bin_zmodload_cond(char *nam, char **args, Options ops)
+{
+    int ret = 0;
+
+    if (OPT_ISSET(ops,'u')) {
+	/* remove autoloaded conditions */
+	for (; *args; args++) {
+	    Conddef cd = getconddef(OPT_ISSET(ops,'I'), *args, 0);
+
+	    if (!cd) {
+		if (!OPT_ISSET(ops,'i')) {
+		    zwarnnam(nam, "%s: no such condition", *args, 0);
+		    ret = 1;
+		}
+	    } else if (cd->flags & CONDF_ADDED) {
+		zwarnnam(nam, "%s: condition is already defined", *args, 0);
+		ret = 1;
+	    } else
+		deleteconddef(cd);
+	}
+	return ret;
+    } else if (!*args) {
+	/* list autoloaded conditions */
+	Conddef p;
+
+	for (p = condtab; p; p = p->next) {
+	    if (p->module) {
+		if (OPT_ISSET(ops,'L')) {
+		    fputs("zmodload -ac", stdout);
+		    if (p->flags & CONDF_INFIX)
+			putchar('I');
+		    printf(" %s %s\n", p->module, p->name);
+		} else {
+		    if (p->flags & CONDF_INFIX)
+			fputs("infix ", stdout);
+		    else
+			fputs("post ", stdout);
+		    printf("%s (%s)\n",p->name, p->module);
+		}
+	    }
+	}
+	return 0;
+    } else {
+	/* add autoloaded conditions */
+	char *modnam;
+
+	modnam = *args++;
+	do {
+	    char *cnam = *args ? *args++ : modnam;
+	    if (strchr(cnam, '/')) {
+		zwarnnam(nam, "%s: `/' is illegal in a condition", cnam, 0);
+		ret = 1;
+	    } else if (add_autocond(cnam, OPT_ISSET(ops,'I'), modnam) &&
+		       !OPT_ISSET(ops,'i')) {
+		zwarnnam(nam, "failed to add condition `%s'", cnam, 0);
+		ret = 1;
+	    }
+	} while(*args);
+	return ret;
+    }
+}
+
+/**/
+static int
+bin_zmodload_math(char *nam, char **args, Options ops)
+{
+    int ret = 0;
+
+    if (OPT_ISSET(ops,'u')) {
+	/* remove autoloaded math functions */
+	for (; *args; args++) {
+	    MathFunc f = getmathfunc(*args, 0);
+
+	    if (!f) {
+		if (!OPT_ISSET(ops,'i')) {
+		    zwarnnam(nam, "%s: no such math function", *args, 0);
+		    ret = 1;
+		}
+	    } else if (f->flags & MFF_ADDED) {
+		zwarnnam(nam, "%s: math function is already defined", *args, 0);
+		ret = 1;
+	    } else
+		deletemathfunc(f);
+	}
+	return ret;
+    } else if (!*args) {
+	/* list autoloaded math functions */
+	MathFunc p;
+
+	for (p = mathfuncs; p; p = p->next) {
+	    if (p->module) {
+		if (OPT_ISSET(ops,'L')) {
+		    fputs("zmodload -af", stdout);
+		    printf(" %s %s\n", p->module, p->name);
+		} else
+		    printf("%s (%s)\n",p->name, p->module);
+	    }
+	}
+	return 0;
+    } else {
+	/* add autoloaded math functions */
+	char *modnam;
+
+	modnam = *args++;
+	do {
+	    char *fnam = *args ? *args++ : modnam;
+	    if (strchr(fnam, '/')) {
+		zwarnnam(nam, "%s: `/' is illegal in a math function",
+			 fnam, 0);
+		ret = 1;
+	    } else if (add_automathfunc(fnam, modnam) && !OPT_ISSET(ops,'i')) {
+		zwarnnam(nam, "failed to add math function `%s'", fnam, 0);
+		ret = 1;
+	    }
+	} while(*args);
+	return ret;
+    }
+}
+
+static void
+printautoparams(HashNode hn, int lon)
+{
+    Param pm = (Param) hn;
+
+    if (pm->flags & PM_AUTOLOAD) {
+	if (lon)
+	    printf("zmodload -ap %s %s\n", pm->u.str, pm->nam);
+	else
+	    printf("%s (%s)\n", pm->nam, pm->u.str);
+    }
+}
+
+/**/
+static int
+bin_zmodload_param(char *nam, char **args, Options ops)
+{
+    int ret = 0;
+
+    if (OPT_ISSET(ops,'u')) {
+	/* remove autoloaded parameters */
+	for (; *args; args++) {
+	    Param pm = (Param) gethashnode2(paramtab, *args);
+
+	    if (!pm) {
+		if (!OPT_ISSET(ops,'i')) {
+		    zwarnnam(nam, "%s: no such parameter", *args, 0);
+		    ret = 1;
+		}
+	    } else if (!(pm->flags & PM_AUTOLOAD)) {
+		zwarnnam(nam, "%s: parameter is already defined", *args, 0);
+		ret = 1;
+	    } else
+		unsetparam_pm(pm, 0, 1);
+	}
+	return ret;
+    } else if (!*args) {
+	scanhashtable(paramtab, 1, 0, 0, printautoparams, OPT_ISSET(ops,'L'));
+	return 0;
+    } else {
+	/* add autoloaded parameters */
+	char *modnam;
+
+	modnam = *args++;
+	do {
+	    char *pnam = *args ? *args++ : modnam;
+	    if (strchr(pnam, '/')) {
+		zwarnnam(nam, "%s: `/' is illegal in a parameter", pnam, 0);
+		ret = 1;
+	    } else
+		add_autoparam(pnam, modnam);
+	} while(*args);
+	return ret;
+    }
+}
+
+/**/
+int
+unload_module(Module m, LinkNode node)
+{
+    /*
+     * Only unload the real module, so resolve aliases.
+     */
+    if (m->flags & MOD_ALIAS) {
+	LinkNode node = find_module(m->u.alias, 1, NULL);
+	if (!node)
+	    return 1;
+	m = (Module) getdata(node);
+    }
+    if ((m->flags & MOD_INIT_S) &&
+	!(m->flags & MOD_UNLOAD) &&
+	((m->flags & MOD_LINKED) ?
+	 (m->u.linked && m->u.linked->cleanup(m)) :
+	 (m->u.handle && cleanup_module(m))))
+	return 1;
+    else {
+	int del = (m->flags & MOD_UNLOAD);
+
+	if (m->wrapper) {
+	    m->flags |= MOD_UNLOAD;
+	    return 0;
+	}
+	m->flags &= ~MOD_UNLOAD;
+	if (m->flags & MOD_INIT_B) {
+	    if (m->flags & MOD_LINKED) {
+		if (m->u.linked) {
+		    m->u.linked->finish(m);
+		    m->u.linked = NULL;
+		}
+	    } else {
+		if (m->u.handle) {
+		    finish_module(m);
+		    m->u.handle = NULL;
+		}
+	    }
+	}
+	if (del && m->deps) {
+	    /* The module was unloaded delayed, unload all modules *
+	     * on which it depended. */
+	    LinkNode n;
+
+	    for (n = firstnode(m->deps); n; incnode(n)) {
+		LinkNode dn = find_module((char *) getdata(n), 1, NULL);
+		Module dm;
+
+		if (dn && (dm = (Module) getdata(dn)) &&
+		    (dm->flags & MOD_UNLOAD)) {
+		    /* See if this is the only module depending on it. */
+
+		    LinkNode an;
+		    Module am;
+		    int du = 1;
+
+		    for (an = firstnode(modules); du && an; incnode(an)) {
+			am = (Module) getdata(an);
+			if (am != m && am->deps &&
+			    ((am->flags & MOD_LINKED) ?
+			     am->u.linked : am->u.handle)) {
+			    LinkNode sn;
+
+			    for (sn = firstnode(am->deps); du && sn;
+				 incnode(sn)) {
+				if (!strcmp((char *) getdata(sn), dm->nam))
+				    du = 0;
+			    }
+			}
+		    }
+		    if (du)
+			unload_module(dm, NULL);
+		}
+	    }
+	}
+	if(!m->deps) {
+	    if (!node) {
+		for (node = firstnode(modules); node; incnode(node))
+		    if (m == (Module) getdata(node))
+			break;
+		if (!node)
+		    return 1;
+	    }
+	    delete_module(node);
+	}
+    }
+    return 0;
+}
+
+/**/
+static int
+bin_zmodload_load(char *nam, char **args, Options ops)
+{
+    LinkNode node;
+    Module m;
+    int ret = 0;
+    if(OPT_ISSET(ops,'u')) {
+	/* unload modules */
+	const char *mname = *args;
+	for(; *args; args++) {
+	    node = find_module(*args, 1, &mname);
+	    if (node) {
+		LinkNode mn, dn;
+		int del = 0;
+
+		for (mn = firstnode(modules); mn; incnode(mn)) {
+		    m = (Module) getdata(mn);
+		    if (m->deps && m->u.handle)
+			for (dn = firstnode(m->deps); dn; incnode(dn))
+			    if (!strcmp((char *) getdata(dn), mname)) {
+				if (m->flags & MOD_UNLOAD)
+				    del = 1;
+				else {
+				    zwarnnam(nam, "module %s is in use by another module and cannot be unloaded", mname, 0);
+				    ret = 1;
+				    goto cont;
+				}
+			    }
+		}
+		m = (Module) getdata(node);
+		if (del)
+		    m->wrapper++;
+		if (unload_module(m, node))
+		    ret = 1;
+		if (del)
+		    m->wrapper--;
+	    } else if (!OPT_ISSET(ops,'i')) {
+		zwarnnam(nam, "no such module %s", *args, 0);
+		ret = 1;
+	    }
+	    cont: ;
+	}
+	return ret;
+    } else if(!*args) {
+	/* list modules */
+	for (node = firstnode(modules); node; incnode(node)) {
+	    m = (Module) getdata(node);
+	    if (m->u.handle && !(m->flags & (MOD_UNLOAD|MOD_ALIAS))) {
+		if(OPT_ISSET(ops,'L')) {
+		    printf("zmodload ");
+		    if(m->nam[0] == '-')
+			fputs("-- ", stdout);
+		    quotedzputs(m->nam, stdout);
+		} else
+		    nicezputs(m->nam, stdout);
+		putchar('\n');
+	    }
+	}
+	return 0;
+    } else {
+	/* load modules */
+	for (; *args; args++)
+	    if (!require_module(nam, *args, 1, (!OPT_ISSET(ops,'i'))))
+		ret = 1;
+
+	return ret;
+    }
+}
+
+/* The list of module-defined conditions. */
+
+/**/
+mod_export Conddef condtab;
+
+/* This gets a condition definition with the given name. The first        *
+ * argument says if we have to look for an infix condition. The last      *
+ * argument is non-zero if we should autoload modules if needed. */
+
+/**/
+Conddef
+getconddef(int inf, char *name, int autol)
+{
+    Conddef p;
+    int f = 1;
+
+    do {
+	for (p = condtab; p; p = p->next) {
+	    if ((!!inf == !!(p->flags & CONDF_INFIX)) &&
+		!strcmp(name, p->name))
+		break;
+	}
+	if (autol && p && p->module) {
+	    /* This is a definition for an autoloaded condition, load the *
+	     * module if we haven't tried that already. */
+	    if (f) {
+		load_module(p->module);
+		f = 0;
+		p = NULL;
+	    } else {
+		deleteconddef(p);
+		return NULL;
+	    }
+	} else
+	    break;
+    } while (!p);
+    return p;
+}
+
+/* This adds the given condition definition. The return value is zero on *
+ * success and 1 on failure. If there is a matching definition for an    *
+ * autoloaded condition, it is removed. */
+
+/**/
+int
+addconddef(Conddef c)
+{
+    Conddef p = getconddef((c->flags & CONDF_INFIX), c->name, 0);
+
+    if (p) {
+	if (!p->module || (p->flags & CONDF_ADDED))
+	    return 1;
+	/* There is an autoload definition. */
+
+	deleteconddef(p);
+    }
+    c->next = condtab;
+    condtab = c;
+    return 0;
+}
+
+/* This adds multiple condition definitions. This is like addbuiltins(). */
+
+/**/
+mod_export int
+addconddefs(char const *nam, Conddef c, int size)
+{
+    int hads = 0, hadf = 0;
+
+    while (size--) {
+	if (c->flags & CONDF_ADDED) {
+	    c++;
+	    continue;
+	}
+	if (addconddef(c)) {
+	    zwarnnam(nam, "name clash when adding condition `%s'", c->name, 0);
+	    hadf = 1;
+	} else {
+	    c->flags |= CONDF_ADDED;
+	    hads = 2;
+	}
+	c++;
+    }
+    return hadf ? hads : 1;
+}
+
+/* This list of hook functions defined. */
+
+/**/
+Hookdef hooktab;
+
+/* Find a hook definition given the name. */
+
+/**/
+Hookdef
+gethookdef(char *n)
+{
+    Hookdef p;
+
+    for (p = hooktab; p; p = p->next)
+	if (!strcmp(n, p->name))
+	    return p;
+    return NULL;
+}
+
+/* This adds the given hook definition. The return value is zero on      *
+ * success and 1 on failure.                                             */
+
+/**/
+int
+addhookdef(Hookdef h)
+{
+    if (gethookdef(h->name))
+	return 1;
+
+    h->next = hooktab;
+    hooktab = h;
+    h->funcs = znewlinklist();
+
+    return 0;
+}
+
+/* This adds multiple hook definitions. This is like addbuiltins(). */
+
+/**/
+mod_export int
+addhookdefs(char const *nam, Hookdef h, int size)
+{
+    int hads = 0, hadf = 0;
+
+    while (size--) {
+	if (addhookdef(h)) {
+	    zwarnnam(nam, "name clash when adding hook `%s'", h->name, 0);
+	    hadf = 1;
+	} else
+	    hads = 2;
+	h++;
+    }
+    return hadf ? hads : 1;
+}
+
+/* Delete hook definitions. */
+
+/**/
+int
+deletehookdef(Hookdef h)
+{
+    Hookdef p, q;
+
+    for (p = hooktab, q = NULL; p && p != h; q = p, p = p->next);
+
+    if (!p)
+	return 1;
+
+    if (q)
+	q->next = p->next;
+    else
+	hooktab = p->next;
+    freelinklist(p->funcs, NULL);
+    return 0;
+}
+
+/**/
+mod_export int
+deletehookdefs(UNUSED(char const *nam), Hookdef h, int size)
+{
+    while (size--) {
+	deletehookdef(h);
+	h++;
+    }
+    return 1;
+}
+
+/* Add a function to a hook. */
+
+/**/
+int
+addhookdeffunc(Hookdef h, Hookfn f)
+{
+    zaddlinknode(h->funcs, (void *) f);
+
+    return 0;
+}
+
+/**/
+mod_export int
+addhookfunc(char *n, Hookfn f)
+{
+    Hookdef h = gethookdef(n);
+
+    if (h)
+	return addhookdeffunc(h, f);
+    return 1;
+}
+
+/* Delete a function from a hook. */
+
+/**/
+int
+deletehookdeffunc(Hookdef h, Hookfn f)
+{
+    LinkNode p;
+
+    for (p = firstnode(h->funcs); p; incnode(p))
+	if (f == (Hookfn) getdata(p)) {
+	    remnode(h->funcs, p);
+	    return 0;
+	}
+    return 1;
+}
+
+/**/
+mod_export int
+deletehookfunc(char *n, Hookfn f)
+{
+    Hookdef h = gethookdef(n);
+
+    if (h)
+	return deletehookdeffunc(h, f);
+    return 1;
+}
+
+/* Run the function(s) for a hook. */
+
+/**/
+mod_export int
+runhookdef(Hookdef h, void *d)
+{
+    if (empty(h->funcs)) {
+	if (h->def)
+	    return h->def(h, d);
+	return 0;
+    } else if (h->flags & HOOKF_ALL) {
+	LinkNode p;
+	int r;
+
+	for (p = firstnode(h->funcs); p; incnode(p))
+	    if ((r = ((Hookfn) getdata(p))(h, d)))
+		return r;
+	if (h->def)
+	    return h->def(h, d);
+	return 0;
+    } else
+	return ((Hookfn) getdata(lastnode(h->funcs)))(h, d);
+}
+
+/**/
+int
+runhook(char *n, void *d)
+{
+    Hookdef h = gethookdef(n);
+
+    if (h)
+	return runhookdef(h, d);
+    return 0;
+}
+
+/* This adds the given parameter definition. The return value is zero on *
+ * success and 1 on failure. */
+
+/**/
+int
+addparamdef(Paramdef d)
+{
+    Param pm;
+
+    if ((pm = (Param) gethashnode2(paramtab, d->name)))
+	unsetparam_pm(pm, 0, 1);
+
+    if (!(pm = createparam(d->name, d->flags)) &&
+	!(pm = (Param) paramtab->getnode(paramtab, d->name)))
+	return 1;
+
+    pm->level = 0;
+    pm->u.data = d->var;
+    if (d->gsu)
+	pm->gsu.i = (GsuInteger) d->gsu;
+    else {
+	/*
+	 * If no get/set/unset class, use the appropriate
+	 * variable type.
+	 */
+	switch (PM_TYPE(pm->flags)) {
+	case PM_SCALAR:
+	    pm->gsu.s = &varscalar_gsu;
+	    break;
+
+	case PM_INTEGER:
+	    pm->gsu.i = &varinteger_gsu;
+	    break;
+
+	case PM_ARRAY:
+	    pm->gsu.a = &vararray_gsu;
+	    break;
+
+	default:
+	    unsetparam_pm(pm, 0, 1);
+	    return 1;
+	}
+    }
+
+    return 0;
+}
+
+/* This adds multiple parameter definitions. This is like addbuiltins(). */
+
+/**/
+mod_export int
+addparamdefs(char const *nam, Paramdef d, int size)
+{
+    int hads = 0, hadf = 0;
+
+    while (size--) {
+	if (addparamdef(d)) {
+	    zwarnnam(nam, "error when adding parameter `%s'", d->name, 0);
+	    hadf = 1;
+	} else
+	    hads = 2;
+	d++;
+    }
+    return hadf ? hads : 1;
+}
+
+/* Delete parameters defined. No error checking yet. */
+
+/**/
+int
+deleteparamdef(Paramdef d)
+{
+    unsetparam(d->name);
+    return 0;
+}
+
+/**/
+mod_export int
+deleteparamdefs(UNUSED(char const *nam), Paramdef d, int size)
+{
+    while (size--) {
+	deleteparamdef(d);
+	d++;
+    }
+    return 1;
+}
+
+/* This adds a definition for autoloading a module for a condition. */
+
+/**/
+int
+add_autocond(char *nam, int inf, char *module)
+{
+    Conddef c = (Conddef) zalloc(sizeof(*c));
+
+    c->name = ztrdup(nam);
+    c->flags = (inf  ? CONDF_INFIX : 0);
+    c->module = ztrdup(module);
+
+    if (addconddef(c)) {
+	zsfree(c->name);
+	zsfree(c->module);
+	zfree(c, sizeof(*c));
+
+	return 1;
+    }
+    return 0;
+}
+
+/* This removes the given condition definition from the list(s). If this *
+ * is a definition for a autoloaded condition, the memory is freed. */
+
+/**/
+int
+deleteconddef(Conddef c)
+{
+    Conddef p, q;
+
+    for (p = condtab, q = NULL; p && p != c; q = p, p = p->next);
+
+    if (p) {
+	if (q)
+	    q->next = p->next;
+	else 
+	    condtab = p->next;
+		
+	if (p->module) {
+	    /* autoloaded, free it */
+	    zsfree(p->name);
+	    zsfree(p->module);
+	    zfree(p, sizeof(*p));
+	}
+	return 0;
+    }
+    return -1;
+}
+
+/* This removes multiple condition definitions (like deletebuiltins()). */
+
+/**/
+mod_export int
+deleteconddefs(char const *nam, Conddef c, int size)
+{
+    int hads = 0, hadf = 0;
+
+    while (size--) {
+	if (!(c->flags & CONDF_ADDED)) {
+	    c++;
+	    continue;
+	}
+	if (deleteconddef(c)) {
+	    zwarnnam(nam, "condition `%s' already deleted", c->name, 0);
+	    hadf = 1;
+	} else
+	    hads = 2;
+	c->flags &= ~CONDF_ADDED;
+	c++;
+    }
+    return hadf ? hads : 1;
+}
+
+/* This adds a definition for autoloading a module for a parameter. */
+
+/**/
+void
+add_autoparam(char *nam, char *module)
+{
+    Param pm;
+
+    queue_signals();
+    if ((pm = (Param) gethashnode2(paramtab, nam)))
+	unsetparam_pm(pm, 0, 1);
+
+    pm = setsparam(nam, ztrdup(module));
+
+    pm->flags |= PM_AUTOLOAD;
+    unqueue_signals();
+}
+
+/* List of math functions. */
+
+/**/
+MathFunc mathfuncs;
+
+/**/
+static void removemathfunc(MathFunc previous, MathFunc current)
+{
+    if (previous)
+	previous->next = current->next;
+    else
+	mathfuncs = current->next;
+
+    zsfree(current->name);
+    zsfree(current->module);
+    zfree(current, sizeof(*current));
+}
+
+/**/
+MathFunc
+getmathfunc(char *name, int autol)
+{
+    MathFunc p, q = NULL;
+
+    for (p = mathfuncs; p; q = p, p = p->next)
+	if (!strcmp(name, p->name)) {
+	    if (autol && p->module) {
+		char *n = dupstring(p->module);
+
+		removemathfunc(q, p);
+
+		load_module(n);
+
+		return getmathfunc(name, 0);
+	    }
+	    return p;
+	}
+
+    return NULL;
+}
+
+/**/
+mod_export int
+addmathfunc(MathFunc f)
+{
+    MathFunc p, q = NULL;
+
+    if (f->flags & MFF_ADDED)
+	return 1;
+
+    for (p = mathfuncs; p; q = p, p = p->next)
+	if (!strcmp(f->name, p->name)) {
+	    if (p->module) {
+		/*
+		 * Autoloadable, replace.
+		 */
+		removemathfunc(q, p);
+		break;
+	    }
+	    return 1;
+	}
+
+    f->flags |= MFF_ADDED;
+    f->next = mathfuncs;
+    mathfuncs = f;
+
+    return 0;
+}
+
+/**/
+mod_export int
+addmathfuncs(char const *nam, MathFunc f, int size)
+{
+    int hads = 0, hadf = 0;
+
+    while (size--) {
+	if (f->flags & MFF_ADDED) {
+	    f++;
+	    continue;
+	}
+	if (addmathfunc(f)) {
+	    zwarnnam(nam, "name clash when adding math function `%s'",
+		     f->name, 0);
+	    hadf = 1;
+	} else
+	    hads = 2;
+	f++;
+    }
+    return hadf ? hads : 1;
+}
+
+/**/
+int
+add_automathfunc(char *nam, char *module)
+{
+    MathFunc f = (MathFunc) zalloc(sizeof(*f));
+
+    f->name = ztrdup(nam);
+    f->module = ztrdup(module);
+    f->flags = 0;
+
+    if (addmathfunc(f)) {
+	zsfree(f->name);
+	zsfree(f->module);
+	zfree(f, sizeof(*f));
+
+	return 1;
+    }
+    f->flags &= ~MFF_ADDED; /* still to autoload, not added yet */
+
+    return 0;
+}
+
+/**/
+mod_export int
+deletemathfunc(MathFunc f)
+{
+    MathFunc p, q;
+
+    for (p = mathfuncs, q = NULL; p && p != f; q = p, p = p->next);
+
+    if (p) {
+	if (q)
+	    q->next = f->next;
+	else
+	    mathfuncs = f->next;
+
+	if (f->module) {
+	    zsfree(f->name);
+	    zsfree(f->module);
+	    zfree(f, sizeof(*f));
+	} else
+	    f->flags &= ~MFF_ADDED;
+
+	return 0;
+    }
+    return -1;
+}
+
+/**/
+mod_export int
+deletemathfuncs(char const *nam, MathFunc f, int size)
+{
+    int hads = 0, hadf = 0;
+
+    while (size--) {
+	if (!(f->flags & MFF_ADDED)) {
+	    f++;
+	    continue;
+	}
+	if (deletemathfunc(f)) {
+	    zwarnnam(nam, "math function `%s' already deleted",
+		     f->name, 0);
+	    hadf = 1;
+	} else
+	    hads = 2;
+	f++;
+    }
+    return hadf ? hads : 1;
+}