xref: /freebsd/libexec/flua/modules/lfs.c (revision 9768746b)
1 /*-
2  * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * Portions derived from https://github.com/keplerproject/luafilesystem under
27  * the terms of the MIT license:
28  *
29  * Copyright (c) 2003-2014 Kepler Project.
30  *
31  * Permission is hereby granted, free of charge, to any person
32  * obtaining a copy of this software and associated documentation
33  * files (the "Software"), to deal in the Software without
34  * restriction, including without limitation the rights to use, copy,
35  * modify, merge, publish, distribute, sublicense, and/or sell copies
36  * of the Software, and to permit persons to whom the Software is
37  * furnished to do so, subject to the following conditions:
38  *
39  * The above copyright notice and this permission notice shall be
40  * included in all copies or substantial portions of the Software.
41  *
42  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
43  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
44  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
45  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
46  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
47  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
48  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
49  * SOFTWARE.
50  */
51 
52 #include <sys/cdefs.h>
53 __FBSDID("$FreeBSD$");
54 
55 #ifndef _STANDALONE
56 #include <sys/stat.h>
57 #include <dirent.h>
58 #include <errno.h>
59 #include <unistd.h>
60 #include <stdio.h>
61 #include <string.h>
62 #endif
63 
64 #include <lua.h>
65 #include "lauxlib.h"
66 #include "lfs.h"
67 
68 #ifdef _STANDALONE
69 #include "lstd.h"
70 #include "lutils.h"
71 #include "bootstrap.h"
72 #endif
73 
74 #ifndef nitems
75 #define	nitems(x)	(sizeof((x)) / sizeof((x)[0]))
76 #endif
77 
78 /*
79  * The goal is to emulate a subset of the upstream Lua FileSystem library, as
80  * faithfully as possible in the boot environment.  Only APIs that seem useful
81  * need to emulated.
82  *
83  * Example usage:
84  *
85  *     for file in lfs.dir("/boot") do
86  *         print("\t"..file)
87  *     end
88  *
89  * Prints:
90  *     .
91  *     ..
92  * (etc.)
93  *
94  * The other available API is lfs.attributes(), which functions somewhat like
95  * stat(2) and returns a table of values.  Example code:
96  *
97  *     attrs, errormsg, errorcode = lfs.attributes("/boot")
98  *     if attrs == nil then
99  *         print(errormsg)
100  *         return errorcode
101  *     end
102  *
103  *     for k, v in pairs(attrs) do
104  *         print(k .. ":\t" .. v)
105  *     end
106  *     return 0
107  *
108  * Prints (on success):
109  *     gid:    0
110  *     change: 140737488342640
111  *     mode:   directory
112  *     rdev:   0
113  *     ino:    4199275
114  *     dev:    140737488342544
115  *     modification:   140737488342576
116  *     size:   512
117  *     access: 140737488342560
118  *     permissions:    755
119  *     nlink:  58283552
120  *     uid:    1001
121  */
122 
123 #define DIR_METATABLE "directory iterator metatable"
124 
125 static int
126 lua_dir_iter_pushtype(lua_State *L __unused, const struct dirent *ent __unused)
127 {
128 
129 	/*
130 	 * This is a non-standard extension to luafilesystem for loader's
131 	 * benefit.  The extra stat() calls to determine the entry type can
132 	 * be quite expensive on some systems, so this speeds up enumeration of
133 	 * /boot greatly by providing the type up front.
134 	 *
135 	 * This extension is compatible enough with luafilesystem, in that we're
136 	 * just using an extra return value for the iterator.
137 	 */
138 #ifdef _STANDALONE
139 	lua_pushinteger(L, ent->d_type);
140 	return 1;
141 #else
142 	return 0;
143 #endif
144 }
145 
146 static int
147 lua_dir_iter_next(lua_State *L)
148 {
149 	struct dirent *entry;
150 	DIR *dp, **dpp;
151 
152 	dpp = (DIR **)luaL_checkudata(L, 1, DIR_METATABLE);
153 	dp = *dpp;
154 	luaL_argcheck(L, dp != NULL, 1, "closed directory");
155 
156 #ifdef _STANDALONE
157 	entry = readdirfd(dp->fd);
158 #else
159 	entry = readdir(dp);
160 #endif
161 	if (entry == NULL) {
162 		closedir(dp);
163 		*dpp = NULL;
164 		return 0;
165 	}
166 
167 	lua_pushstring(L, entry->d_name);
168 	return 1 + lua_dir_iter_pushtype(L, entry);
169 }
170 
171 static int
172 lua_dir_iter_close(lua_State *L)
173 {
174 	DIR *dp, **dpp;
175 
176 	dpp = (DIR **)lua_touserdata(L, 1);
177 	dp = *dpp;
178 	if (dp == NULL)
179 		return 0;
180 
181 	closedir(dp);
182 	*dpp = NULL;
183 	return 0;
184 }
185 
186 static int
187 lua_dir(lua_State *L)
188 {
189 	const char *path;
190 	DIR *dp;
191 
192 	if (lua_gettop(L) != 1) {
193 		lua_pushnil(L);
194 		return 1;
195 	}
196 
197 	path = luaL_checkstring(L, 1);
198 	dp = opendir(path);
199 	if (dp == NULL) {
200 		lua_pushnil(L);
201 		return 1;
202 	}
203 
204 	lua_pushcfunction(L, lua_dir_iter_next);
205 	*(DIR **)lua_newuserdata(L, sizeof(DIR **)) = dp;
206 	luaL_getmetatable(L, DIR_METATABLE);
207 	lua_setmetatable(L, -2);
208 	return 2;
209 }
210 
211 static void
212 register_metatable(lua_State *L)
213 {
214 	/*
215 	 * Create so-called metatable for iterator object returned by
216 	 * lfs.dir().
217 	 */
218 	luaL_newmetatable(L, DIR_METATABLE);
219 
220 	lua_newtable(L);
221 	lua_pushcfunction(L, lua_dir_iter_next);
222 	lua_setfield(L, -2, "next");
223 	lua_pushcfunction(L, lua_dir_iter_close);
224 	lua_setfield(L, -2, "close");
225 
226 	/* Magically associate anonymous method table with metatable. */
227 	lua_setfield(L, -2, "__index");
228 	/* Implement magic destructor method */
229 	lua_pushcfunction(L, lua_dir_iter_close);
230 	lua_setfield(L, -2, "__gc");
231 
232 	lua_pop(L, 1);
233 }
234 
235 #define PUSH_INTEGER(lname, stname)				\
236 static void							\
237 push_st_ ## lname (lua_State *L, struct stat *sb)		\
238 {								\
239 	lua_pushinteger(L, (lua_Integer)sb->st_ ## stname);	\
240 }
241 PUSH_INTEGER(dev, dev)
242 PUSH_INTEGER(ino, ino)
243 PUSH_INTEGER(nlink, nlink)
244 PUSH_INTEGER(uid, uid)
245 PUSH_INTEGER(gid, gid)
246 PUSH_INTEGER(rdev, rdev)
247 PUSH_INTEGER(access, atime)
248 PUSH_INTEGER(modification, mtime)
249 PUSH_INTEGER(change, ctime)
250 PUSH_INTEGER(size, size)
251 #undef PUSH_INTEGER
252 
253 static void
254 push_st_mode(lua_State *L, struct stat *sb)
255 {
256 	const char *mode_s;
257 	mode_t mode;
258 
259 	mode = (sb->st_mode & S_IFMT);
260 	if (S_ISREG(mode))
261 		mode_s = "file";
262 	else if (S_ISDIR(mode))
263 		mode_s = "directory";
264 	else if (S_ISLNK(mode))
265 		mode_s = "link";
266 	else if (S_ISSOCK(mode))
267 		mode_s = "socket";
268 	else if (S_ISFIFO(mode))
269 		mode_s = "fifo";
270 	else if (S_ISCHR(mode))
271 		mode_s = "char device";
272 	else if (S_ISBLK(mode))
273 		mode_s = "block device";
274 	else
275 		mode_s = "other";
276 
277 	lua_pushstring(L, mode_s);
278 }
279 
280 static void
281 push_st_permissions(lua_State *L, struct stat *sb)
282 {
283 	char buf[20];
284 
285 	/*
286 	 * XXX
287 	 * Could actually format as "-rwxrwxrwx" -- do we care?
288 	 */
289 	snprintf(buf, sizeof(buf), "%o", sb->st_mode & ~S_IFMT);
290 	lua_pushstring(L, buf);
291 }
292 
293 #define PUSH_ENTRY(n)	{ #n, push_st_ ## n }
294 struct stat_members {
295 	const char *name;
296 	void (*push)(lua_State *, struct stat *);
297 } members[] = {
298 	PUSH_ENTRY(mode),
299 	PUSH_ENTRY(dev),
300 	PUSH_ENTRY(ino),
301 	PUSH_ENTRY(nlink),
302 	PUSH_ENTRY(uid),
303 	PUSH_ENTRY(gid),
304 	PUSH_ENTRY(rdev),
305 	PUSH_ENTRY(access),
306 	PUSH_ENTRY(modification),
307 	PUSH_ENTRY(change),
308 	PUSH_ENTRY(size),
309 	PUSH_ENTRY(permissions),
310 };
311 #undef PUSH_ENTRY
312 
313 static int
314 lua_attributes(lua_State *L)
315 {
316 	struct stat sb;
317 	const char *path, *member;
318 	size_t i;
319 	int rc;
320 
321 	path = luaL_checkstring(L, 1);
322 	if (path == NULL) {
323 		lua_pushnil(L);
324 		lua_pushfstring(L, "cannot convert first argument to string");
325 		lua_pushinteger(L, EINVAL);
326 		return 3;
327 	}
328 
329 	rc = stat(path, &sb);
330 	if (rc != 0) {
331 		lua_pushnil(L);
332 		lua_pushfstring(L,
333 		    "cannot obtain information from file '%s': %s", path,
334 		    strerror(errno));
335 		lua_pushinteger(L, errno);
336 		return 3;
337 	}
338 
339 	if (lua_isstring(L, 2)) {
340 		member = lua_tostring(L, 2);
341 		for (i = 0; i < nitems(members); i++) {
342 			if (strcmp(members[i].name, member) != 0)
343 				continue;
344 
345 			members[i].push(L, &sb);
346 			return 1;
347 		}
348 		return luaL_error(L, "invalid attribute name '%s'", member);
349 	}
350 
351 	/* Create or reuse existing table */
352 	lua_settop(L, 2);
353 	if (!lua_istable(L, 2))
354 		lua_newtable(L);
355 
356 	/* Export all stat data to caller */
357 	for (i = 0; i < nitems(members); i++) {
358 		lua_pushstring(L, members[i].name);
359 		members[i].push(L, &sb);
360 		lua_rawset(L, -3);
361 	}
362 	return 1;
363 }
364 
365 #ifndef _STANDALONE
366 #define	lfs_mkdir_impl(path)	(mkdir((path), \
367     S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | \
368     S_IROTH | S_IXOTH))
369 
370 static int
371 lua_mkdir(lua_State *L)
372 {
373 	const char *path;
374 	int error, serrno;
375 
376 	path = luaL_checkstring(L, 1);
377 	if (path == NULL) {
378 		lua_pushnil(L);
379 		lua_pushfstring(L, "cannot convert first argument to string");
380 		lua_pushinteger(L, EINVAL);
381 		return 3;
382 	}
383 
384 	error = lfs_mkdir_impl(path);
385 	if (error == -1) {
386 		/* Save it; unclear what other libc functions may be invoked */
387 		serrno = errno;
388 		lua_pushnil(L);
389 		lua_pushfstring(L, strerror(serrno));
390 		lua_pushinteger(L, serrno);
391 		return 3;
392 	}
393 
394 	lua_pushboolean(L, 1);
395 	return 1;
396 }
397 
398 static int
399 lua_rmdir(lua_State *L)
400 {
401 	const char *path;
402 	int error, serrno;
403 
404 	path = luaL_checkstring(L, 1);
405 	if (path == NULL) {
406 		lua_pushnil(L);
407 		lua_pushfstring(L, "cannot convert first argument to string");
408 		lua_pushinteger(L, EINVAL);
409 		return 3;
410 	}
411 
412 	error = rmdir(path);
413 	if (error == -1) {
414 		/* Save it; unclear what other libc functions may be invoked */
415 		serrno = errno;
416 		lua_pushnil(L);
417 		lua_pushfstring(L, strerror(serrno));
418 		lua_pushinteger(L, serrno);
419 		return 3;
420 	}
421 
422 	lua_pushboolean(L, 1);
423 	return 1;
424 }
425 #endif
426 
427 #define REG_SIMPLE(n)	{ #n, lua_ ## n }
428 static const struct luaL_Reg fslib[] = {
429 	REG_SIMPLE(attributes),
430 	REG_SIMPLE(dir),
431 #ifndef _STANDALONE
432 	REG_SIMPLE(mkdir),
433 	REG_SIMPLE(rmdir),
434 #endif
435 	{ NULL, NULL },
436 };
437 #undef REG_SIMPLE
438 
439 int
440 luaopen_lfs(lua_State *L)
441 {
442 	register_metatable(L);
443 	luaL_newlib(L, fslib);
444 #ifdef _STANDALONE
445 	/* Non-standard extension for loader, used with lfs.dir(). */
446 	lua_pushinteger(L, DT_DIR);
447 	lua_setfield(L, -2, "DT_DIR");
448 #endif
449 	return 1;
450 }
451