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librazor/lua.c
author J. Ali Harlow <ali@juiblex.co.uk>
Fri Apr 17 21:09:55 2009 +0100 (2009-04-17)
changeset 357 39f8dab73084
child 361 2523d03a840e
permissions -rw-r--r--
Add hashtable test to expose confusion as to whether 0 is a valid value or not 
     1 /*

     2  * Copyright (C) 2009  J. Ali Harlow <ali@juiblex.co.uk>

     3  *

     4  * This program is free software; you can redistribute it and/or modify

     5  * it under the terms of the GNU General Public License as published by

     6  * the Free Software Foundation; either version 2 of the License, or

     7  * (at your option) any later version.

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License along

    15  * with this program; if not, write to the Free Software Foundation, Inc.,

    16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

    17  */

    18 

    19 #include "config.h"

    20 

    21 #include <stdlib.h>

    22 #include <string.h>

    23 #include <stdio.h>

    24 #include <errno.h>

    25 #include <sys/stat.h>

    26 #include <sys/types.h>

    27 #include <lua.h>

    28 #include <lualib.h>

    29 #include <lauxlib.h>

    30 

    31 #include "razor.h"

    32 #include "razor-internal.h"

    33 

    34 #define MAX_ARGS		2

    35 

    36 #define ARG_FLAG_OPT		0x1

    37 #define ARG_FLAG_BYPASS		0x2

    38 

    39 #define ARG(flags, swtch, index, type) \

    40 				((flags) << 26 | (swtch) << 21 | \

    41 				 (index) << 16 | type)

    42 #define ARG_FLAGS(arg)		((unsigned)(arg) >> 26)

    43 #define ARG_SWTCH(arg)		((unsigned)(arg) >> 21 & 0x1F)

    44 #define ARG_INDEX(arg)		((unsigned)(arg) >> 16 & 0x1F)

    45 #define ARG_TYPE(arg)		((unsigned)(arg) & 0xFFFF)

    46 

    47 #define ARG_NONE		0

    48 #define ARG_STRING(n)		ARG(0, 0, n, LUA_TSTRING)

    49 #define ARG_OPT_STRING(n)	ARG(ARG_FLAG_OPT, 0, n, LUA_TSTRING)

    50 #define ARG_BYP_STRING(n, s)	ARG(ARG_FLAG_BYPASS, s, n, LUA_TSTRING)

    51 

    52 struct razor_proxy {

    53 	char *table, *name;

    54 	int result;

    55 	unsigned args[MAX_ARGS];

    56 };

    57 

    58 static struct razor_proxy proxy[] = {

    59 	{ NULL, "dofile", LUA_TNONE, { ARG_STRING(1) } },

    60 	{ NULL, "loadfile", LUA_TNONE, { ARG_OPT_STRING(1) } },

    61 	{ "io", "input", LUA_TNONE, { ARG_OPT_STRING(1) } },

    62 	{ "io", "output", LUA_TNONE, { ARG_OPT_STRING(1) } },

    63 	{ "io", "lines", LUA_TNONE, { ARG_OPT_STRING(1) } },

    64 	{ "io", "open", LUA_TNONE, { ARG_STRING(1) } },

    65 	{ "io", "popen", LUA_TNONE, { ARG_STRING(1) } },

    66 	/*

    67 	 * Note: We do not proxy os.execute

    68 	 * We can't do it properly (there is no way to distinguish filenames

    69 	 * in arguments from any other strings) so it's better not to try.

    70 	 * Scripts that attempt to be portable should use posix.exec[p]

    71 	 */

    72 	{ "os", "remove", LUA_TNONE, { ARG_STRING(1) } },

    73 	{ "os", "rename", LUA_TNONE, { ARG_STRING(1), ARG_STRING(2) } },

    74 	/*

    75 	 * Note: We do not proxy os.tmpname

    76 	 * It should never be used. scripts should use io.tmpfile instead

    77 	 * if the rather limited functionality it provides suffices. The

    78 	 * proper solution is to implement posix.mkstemp

    79 	 */

    80 	{ "posix", "access", LUA_TNONE, { ARG_STRING(1) } },

    81 	{ "posix", "chdir", LUA_TNONE, { ARG_STRING(1) } },

    82 	{ "posix", "chmod", LUA_TNONE, { ARG_STRING(1) } },

    83 	{ "posix", "chown", LUA_TNONE, { ARG_STRING(1) } },

    84 	{ "posix", "dir", LUA_TNONE, { ARG_OPT_STRING(1) } },

    85 	{ "posix", "exec", LUA_TNONE, { ARG_STRING(1) } },

    86 	{ "posix", "execp", LUA_TNONE, { ARG_STRING(1) } },

    87 	{ "posix", "files", LUA_TNONE, { ARG_OPT_STRING(1) } },

    88 	{ "posix", "getcwd", LUA_TSTRING, { ARG_NONE } },

    89 	{ "posix", "glob", LUA_TTABLE, { ARG_STRING(1) } },

    90 	{ "posix", "link", LUA_TNONE, { ARG_BYP_STRING(1, 3), ARG_STRING(2) } },

    91 	{ "posix", "mkdir", LUA_TNONE, { ARG_STRING(1) } },

    92 	{ "posix", "mkfifo", LUA_TNONE, { ARG_STRING(1) } },

    93 	{ "posix", "pathconf", LUA_TNONE, { ARG_STRING(1) } },

    94 	{ "posix", "readlink", LUA_TNONE, { ARG_STRING(1) } },

    95 	{ "posix", "rmdir", LUA_TNONE, { ARG_STRING(1) } },

    96 	{ "posix", "stat", LUA_TNONE, { ARG_STRING(1) } },

    97 	{ "posix", "unlink", LUA_TNONE, { ARG_STRING(1) } },

    98 	{ "posix", "utime", LUA_TNONE, { ARG_STRING(1) } },

    99 };

   100 

   101 static lua_CFunction execp_handler;

   102 

   103 struct razor_lua {

   104 	const char *root;

   105 	lua_CFunction handler[ARRAY_SIZE(proxy)];

   106 };

   107 

   108 static void *alloc_lua(void *user_data, void *ptr, size_t osize, size_t nsize)

   109 {

   110 	if (!nsize) {

   111 		free(ptr);

   112 		return NULL;

   113 	} else

   114 		return realloc(ptr, nsize);

   115 }

   116 

   117 static int proxy_execp(lua_State *L)

   118 {

   119 	int r, n, err, got_eacces = 0;

   120 	char *file = strdup(luaL_checkstring(L, 1));

   121 	char *exe;

   122 	const char *s, *e, *path;

   123 	struct razor_lua *rl;

   124 

   125 	if (*file == '\0' || strchr(file, '/')) {

   126 		r = execp_handler(L);

   127 		free(file);

   128 		return r;

   129 	}

   130 

   131 	(void)lua_getallocf(L, (void **)&rl);

   132 

   133 	path = getenv("PATH");

   134 	if (!path)

   135 		path = ":/bin:/usr/bin";

   136 

   137 	s = path;

   138 	for (;;) {

   139 		e = strchr(s, ':');

   140 		if (!e)

   141 			e = s + strlen(s);

   142 		if (*s == '/') {

   143 			n = strlen(rl->root);

   144 			exe = malloc(n + (e - s) + 1 + strlen(file) + 1);

   145 			memcpy(exe, rl->root, n);

   146 			memcpy(exe + n, s, e - s);

   147 			n += e - s;

   148 			exe[n++] = '/';

   149 			strcpy(exe + n, file);

   150 		} else if (e != s) {

   151 			exe = malloc((e - s) + 1 + strlen(file) + 1);

   152 			memcpy(exe, s, e - s);

   153 			n = e - s;

   154 			exe[n++] = '/';

   155 			strcpy(exe + n, file);

   156 		} else {

   157 			/* Ensure exe contains a slash to avoid PATH search */

   158 			exe = malloc(2 + strlen(file) + 1);

   159 			exe[0] = '.';

   160 			exe[1] = '/';

   161 			strcpy(exe + 2, file);

   162 		}

   163 		lua_pushstring(L, exe);

   164 		lua_replace(L, 1);

   165 		free(exe);

   166 		n = lua_gettop(L);

   167 		r = execp_handler(L);

   168 

   169 		err = lua_tointeger(L, -1);

   170 		switch (err) {

   171 		case EACCES:

   172 			got_eacces = 1;

   173 			/* Fall through */

   174 		case ENOENT:

   175 		case ESTALE:

   176 		case ENOTDIR:

   177 		case ENODEV:

   178 		case ETIMEDOUT:

   179 			lua_pop(L, lua_gettop(L) - n);

   180 			break;

   181 		default:

   182 			free(file);

   183 			return r;

   184 		}

   185 

   186 		if (*e)

   187 			s = e + 1;

   188 		else

   189 			break;

   190 	}

   191 

   192 	if (got_eacces)

   193 		err = EACCES;

   194 

   195 	lua_pushnil(L);

   196 	lua_pushfstring(L, "%s: %s", file, strerror(err));

   197 	lua_pushinteger(L, err);

   198 

   199 	free(file);

   200 	return 3;

   201 }

   202 

   203 static int real2fake(lua_State *L, struct razor_lua *rl, int indx)

   204 {

   205 	const char *path;

   206 

   207 	if (indx < 0)

   208 		indx += lua_gettop(L) + 1;

   209 

   210 	if (lua_type(L, indx) == LUA_TSTRING) {

   211 		path = lua_tostring(L, indx);

   212 		if (path && !strncmp(path, rl->root, strlen(rl->root)) &&

   213 		   (path[strlen(rl->root)] == '/' || !path[strlen(rl->root)])) {

   214 			lua_pushstring(L, path + strlen(rl->root));

   215 			lua_replace(L, indx);

   216 			return 1;

   217 		}

   218 	}

   219 

   220 	return 0;

   221 }

   222 

   223 static int proxy_handler(lua_State *L)

   224 {

   225 	int i, retval, cond;

   226 	unsigned arg;

   227 	const char *path;

   228 	struct razor_lua *rl;

   229 	int method = lua_tointeger(L, lua_upvalueindex(1));

   230 	struct razor_proxy *rp = proxy + method;

   231 

   232 	(void)lua_getallocf(L, (void **)&rl);

   233 

   234 	for(i = 0; i < MAX_ARGS; i++) {

   235 		arg = rp->args[i];

   236 		if (arg == ARG_NONE)

   237 			continue;

   238 		switch (ARG_TYPE(arg)) {

   239 		case LUA_TSTRING:

   240 			if (ARG_FLAGS(arg) & ARG_FLAG_BYPASS)

   241 				cond = !lua_toboolean(L, ARG_SWTCH(arg));

   242 			else

   243 				cond = 1;

   244 			if (ARG_FLAGS(arg) & ARG_FLAG_OPT) {

   245 				if (lua_isstring(L, ARG_INDEX(arg)))

   246 					path = lua_tostring(L, ARG_INDEX(arg));

   247 				else

   248 					path = NULL;

   249 			} else

   250 				path = luaL_checkstring(L, ARG_INDEX(arg));

   251 			if (cond && path && *path == '/') {

   252 				lua_pushfstring(L, "%s%s", rl->root, path);

   253 				lua_replace(L, ARG_INDEX(arg));

   254 			}

   255 			break;

   256 		default:

   257 			lua_pushfstring(L, "razor proxy: Unhandled type (%d)",

   258 					ARG_TYPE(arg));

   259 			lua_error(L);

   260 		}

   261 	}

   262 

   263 	retval = rl->handler[method](L);

   264 

   265 	if (rp->result != LUA_TNONE && !lua_isnil(L, 1)) {

   266 		switch (rp->result) {

   267 		case LUA_TNONE:

   268 			break;

   269 		case LUA_TSTRING:

   270 			real2fake(L, rl, -1);

   271 			break;

   272 		case LUA_TTABLE:

   273 			lua_pushnil(L);

   274 			while (lua_next(L, -2)) {

   275 				if (real2fake(L, rl, -1)) {

   276 					i = lua_tonumber(L, -2);

   277 					lua_rawseti(L, -3, i);

   278 				} else

   279 					lua_pop(L, 1);

   280 			}

   281 			break;

   282 		default:

   283 			lua_pushfstring(L, "razor proxy: Unhandled type (%d)",

   284 					rp->result);

   285 			lua_error(L);

   286 		}

   287 	}

   288 

   289 	return retval;

   290 }

   291 

   292 int run_lua_script(const char *root, const char *name, const char *body,

   293 		   ssize_t len)

   294 {

   295 	int i, n;

   296 	lua_State *L;

   297 	struct razor_lua rl;

   298 

   299 	if (root && strcmp(root, "/"))

   300 		rl.root = root;

   301 	else

   302 		rl.root = NULL;

   303 

   304 	L = lua_newstate(alloc_lua, &rl);

   305 	luaL_openlibs(L);

   306 	lua_getglobal(L, "require");

   307 	lua_pushstring(L, "posix");

   308 	if (lua_pcall(L, 1, 1, 0)) {

   309 		fprintf(stderr, "lua posix: %s\n", lua_tostring(L, -1));

   310 		lua_pop(L, 1);

   311 		lua_close(L);

   312 		return -1;

   313 	}

   314 

   315 	if (rl.root)

   316 		for(i = 0; i < ARRAY_SIZE(proxy); i++) {

   317 			if (proxy[i].table) {

   318 				lua_getglobal(L, proxy[i].table);

   319 				n = lua_gettop(L);

   320 			} else

   321 				n = LUA_GLOBALSINDEX;

   322 			lua_getfield(L, n, proxy[i].name);

   323 			rl.handler[i] = lua_tocfunction(L, -1);

   324 			lua_getfenv(L, -1);

   325 			lua_remove(L, -2);

   326 			if (proxy[i].table &&

   327 			    !strcmp(proxy[i].table, "posix") &&

   328 			    !strcmp(proxy[i].name, "execp")) {

   329 				execp_handler = rl.handler[i];

   330 				rl.handler[i] = proxy_execp;

   331 			}

   332 			lua_pushinteger(L, i);

   333 			lua_pushcclosure(L, proxy_handler, 1);

   334 			lua_pushvalue(L, -2);

   335 			lua_setfenv(L, -2);

   336 			lua_setfield(L, n, proxy[i].name);

   337 			if (proxy[i].table)

   338 				lua_pop(L, 2);

   339 			else

   340 				lua_pop(L, 1);

   341 		}

   342 

   343 	if (len < 0)

   344 		len = strlen(body);

   345 

   346 	if (luaL_loadbuffer(L, body, len, name)) {

   347 		fprintf(stderr, "failed to load lua script\n");

   348 		lua_close(L);

   349 		return -1;

   350 	}

   351 

   352 	if (lua_pcall(L, 0, 0, 0)) {

   353 		fprintf(stderr, "lua script failed: %s\n", lua_tostring(L, -1));

   354 		lua_pop(L, 1);

   355 		lua_close(L);

   356 		return -1;

   357 	}

   358 

   359 	lua_close(L);

   360 	return 0;

   361 }
razor