1 files changed, 383 insertions, 0 deletions
diff --git a/libs/lucittpd/src/lib/luaplugin.c b/libs/lucittpd/src/lib/luaplugin.c
new file mode 100644
index 000000000..6a0e1caad
--- /dev/null
+++ b/libs/lucittpd/src/lib/luaplugin.c
@@ -0,0 +1,383 @@
+/*
+ * luaplugin - fast lua plugin indexing
+ * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/cdefs.h>
+
+#ifndef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE /* XXX: portability hack for timestamp */
+#endif
+
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <limits.h>
+#include <glob.h>
+
+#include <lualib.h>
+#include <lauxlib.h>
+#include <lib/list.h>
+#include <lib/luaplugin.h>
+
+//#define DEBUG 1
+#ifdef DEBUG
+#define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
+#else
+#define DPRINTF(...) do {} while (0)
+#endif
+
+/**
+ * list_for_each_offset	-	iterate over a list, start with the provided pointer
+ * @pos:	the &struct list_head to use as a loop cursor.
+ * @head:	the head for your list.
+ */
+#define list_for_each_offset(pos, head, offset) \
+	for (pos = (offset)->next; pos != (offset); \
+	     pos = ((pos->next == (head)) && ((offset) != (head)) ? (head)->next : pos->next))
+
+static char pbuf[PATH_MAX];
+static void load_module(struct luaplugin_ctx *ctx, struct luaplugin_entry *e);
+
+static struct luaplugin_entry *
+find_entry(struct luaplugin_ctx *ctx, const char *name, bool modname)
+{
+	struct list_head *p;
+
+	if (!ctx->last)
+		ctx->last = &ctx->entries;
+
+	list_for_each_offset(p, &ctx->entries, ctx->last) {
+		struct luaplugin_entry *e;
+		const char *cmp;
+
+		e = container_of(p, struct luaplugin_entry, list);
+		if (modname)
+			cmp = e->module;
+		else
+			cmp = e->name;
+
+		if (!strcmp(cmp, name))
+			return e;
+	}
+	return NULL;
+}
+
+static struct luaplugin_entry *
+new_entry(struct luaplugin_ctx *ctx, const char *name, const char *modname)
+{
+	struct luaplugin_entry *e;
+	char *c;
+
+	e = malloc(sizeof(struct luaplugin_entry));
+	if (!e)
+		goto error;
+
+	memset(e, 0, sizeof(struct luaplugin_entry));
+	INIT_LIST_HEAD(&e->list);
+	e->ctx = ctx;
+	e->loaded = false;
+
+	e->name = strdup(name);
+	if (!e->name)
+		goto error1;
+
+	e->module = strdup(modname);
+	if (!e->module)
+		goto error2;
+
+	/* strip filename extension */
+	c = strrchr(e->module, '.');
+	if (c)
+		*c = 0;
+
+	/* lua namespace: replace / with . */
+	c = e->module;
+	while ((c = strchr(c, '/')) != NULL) {
+		*c = '.';
+	}
+	return e;
+
+error2:
+	free(e->name);
+error1:
+	free(e);
+error:
+	return NULL;
+}
+
+static const char *module_loader =
+"loader = function (newgt, filename)\n"
+"	setmetatable(newgt, { __index = _G })\n"
+"	local f = loadfile(filename)\n"
+"	if (type(f) == \"function\") then\n"
+"		setfenv(f, newgt)\n"
+"		f()\n"
+"	else\n"
+"		error(f)\n"
+"	end\n"
+"end\n";
+
+static void
+access_plugin_table (lua_State *L, const char *modname, bool set)
+{
+	const char *e;
+
+	lua_pushvalue(L, LUA_GLOBALSINDEX);
+	do {
+		bool _set = true;
+
+		e = strchr(modname, '.');
+		if (e == NULL) {
+			e = modname + strlen(modname);
+			_set = set;
+		}
+
+		lua_pushlstring(L, modname, e - modname);
+		lua_rawget(L, -2);
+		if (lua_isnil(L, -1) ||
+		    /* no such field or last field */
+		    (lua_istable(L, -1) && (*e != '.'))) {
+			lua_pop(L, 1);  /* remove this result */
+
+			if (_set) {
+				if (*e != '.')
+					lua_pushvalue(L, -2); /* use table from given index */
+				else
+					lua_createtable(L, 0, 1); /* new table for field */
+			}
+
+			lua_pushlstring(L, modname, e - modname);
+
+			if (_set) {
+				lua_pushvalue(L, -2);
+				lua_settable(L, -4);  /* set new table into field */
+			} else {
+				lua_gettable(L, -2);
+			}
+		}
+		else if (!lua_istable(L, -1)) {  /* field has a non-table value? */
+			lua_pop(L, 2 + !!set);  /* remove table and values */
+			return;
+		}
+		lua_remove(L, -2);  /* remove previous table */
+		modname = e + 1;
+	} while (*e == '.');
+	if (set)
+		lua_pop(L, 2);
+}
+
+
+static void
+load_module(struct luaplugin_ctx *ctx, struct luaplugin_entry *e)
+{
+	lua_State *L = ctx->L;
+	int ret;
+
+	/* grab the loader wrapper function */
+	ret = luaL_dostring(L, module_loader);
+	if (ret)
+		return;
+
+	lua_getglobal(L, "loader");
+	lua_pushnil(L);
+	lua_setglobal(L, "loader");
+
+	e->loaded = true;
+	e->reload = false;
+
+	/* new environment table for function call */
+	lua_newtable(L);
+
+	/* register the table globally */
+	lua_pushvalue(L, -1);
+	access_plugin_table(L, e->module, true);
+
+	lua_pushstring(L, e->name);
+
+	if (lua_pcall(L, 2, 0, 0) != 0) {
+		const char *err = "unknown error";
+
+		if (lua_isstring(L, -1))
+			err = lua_tostring(L, -1);
+
+		fprintf(stderr, err);
+	}
+}
+
+static void
+free_entry(struct luaplugin_ctx *ctx, struct luaplugin_entry *e)
+{
+	lua_State *L = ctx->L;
+
+	if (e->loaded && L) {
+		/* allow the gc to free the module */
+		lua_pushnil(L);
+		access_plugin_table(L, e->module, true);
+	}
+	list_del(&e->list);
+	free(e->name);
+	free(e->module);
+	free(e);
+}
+
+static void
+__luaplugin_scan(struct luaplugin_ctx *ctx, int base_len, int rec)
+{
+	int gl_flags = GLOB_NOESCAPE | GLOB_NOSORT | GLOB_MARK;
+	glob_t gl;
+	int i;
+
+	strncpy(pbuf + base_len, "*.lua", PATH_MAX - base_len);
+	if (glob(pbuf, gl_flags, NULL, &gl) < 0) {
+		globfree(&gl);
+		return;
+	}
+
+	for (i = 0; i < gl.gl_pathc; i++) {
+		const char *entry = gl.gl_pathv[i];
+		struct luaplugin_entry *e;
+		struct stat st;
+		int elen;
+
+		elen = strlen(entry);
+
+		/* should not happen */
+		if ((elen <= base_len) || (strncmp(entry, pbuf, base_len) != 0)) {
+			fprintf(stderr, "[%s] sanity check failed in %s(%d)!\n", __FILE__, __func__, __LINE__);
+			continue;
+		}
+
+		/* descend into subdirectories */
+		if (entry[elen - 1] == '/') {
+			strncpy(pbuf + base_len, entry + base_len, PATH_MAX - base_len);
+			__luaplugin_scan(ctx, base_len, rec + 1);
+			pbuf[base_len] = '\0';
+			continue;
+		}
+
+		if (stat(gl.gl_pathv[i], &st))
+			continue;
+
+		if ((st.st_mode & S_IFMT) != S_IFREG)
+			continue;
+
+		e = find_entry(ctx, entry + base_len, false);
+		if (!e) {
+			e = new_entry(ctx, entry, entry + base_len);
+			list_add_tail(&e->list, &ctx->entries);
+		}
+		if (!e)
+			continue;
+
+		e->checked = ctx->checked;
+		e->reload = (e->timestamp < st.st_mtime);
+		e->timestamp = st.st_mtime;
+	}
+	globfree(&gl);
+}
+
+int
+luaplugin_call(struct luaplugin_entry *e, int narg)
+{
+	struct luaplugin_ctx *ctx = e->ctx;
+	lua_State *L = ctx->L;
+	const char *func;
+	int ret;
+
+	func = luaL_checkstring(L, -1 - narg);
+
+	/* grab a reference to the plugin's table */
+	access_plugin_table(L, e->module, false);
+	lua_getfield(L, -1, func);
+	if (!lua_isfunction(L, -1)) {
+		lua_pop(L, narg + 1);
+		ret = -ENOENT;
+		goto done;
+	}
+
+	/* replace function name with a ref to the function */
+	lua_replace(L, -3 - narg);
+
+	/* pop the table */
+	lua_pop(L, 1);
+	ret = lua_pcall(L, narg, 0, 0);
+
+	if (ret != 0) {
+		fprintf(stderr, lua_tostring(L, -1));
+	}
+
+done:
+	return ret;
+}
+
+void
+luaplugin_scan(struct luaplugin_ctx *ctx)
+{
+	struct list_head *tmp, *p;
+
+	sprintf(pbuf, "%s/", ctx->path);
+
+	ctx->checked++;
+	__luaplugin_scan(ctx, strlen(pbuf), 0);
+
+	/* expire old entries */
+	list_for_each_safe(p, tmp, &ctx->entries) {
+		struct luaplugin_entry *e = container_of(p, struct luaplugin_entry, list);
+		if (e->checked < ctx->checked)
+			free_entry(ctx, e);
+		else if (e->reload)
+			load_module(ctx, e);
+	}
+}
+
+int
+luaplugin_init(struct luaplugin_ctx *ctx, const char *path)
+{
+	memset(ctx, 0, sizeof(struct luaplugin_ctx));
+	INIT_LIST_HEAD(&ctx->entries);
+	ctx->path = path;
+
+	ctx->L = luaL_newstate();
+	if (!ctx->L)
+		return -ENOMEM;
+
+	luaL_openlibs(ctx->L);
+
+	/* disable the module functionality, a plugin is restricted to its own environment */
+	/*
+	lua_pushcfunction(ctx->L, luaplugin_module);
+	lua_setfield(ctx->L, LUA_GLOBALSINDEX, "module");
+	*/
+
+	return 0;
+}
+
+void
+luaplugin_done(struct luaplugin_ctx *ctx)
+{
+	struct list_head *p, *tmp;
+
+	lua_close(ctx->L);
+	ctx->L = NULL;
+
+	list_for_each_safe(p, tmp, &ctx->entries) {
+		struct luaplugin_entry *e;
+		e = container_of(p, struct luaplugin_entry, list);
+		free_entry(ctx, e);
+	}
+}