1 /*
2 ** LuaFileSystem
3 ** Copyright Kepler Project 2003 (http://www.keplerproject.org/luafilesystem)
4 **
5 ** File system manipulation library.
6 ** This library offers these functions:
7 **   lfs.attributes (filepath [, attributename])
8 **   lfs.chdir (path)
9 **   lfs.currentdir ()
10 **   lfs.dir (path)
11 **   lfs.lock (fh, mode)
12 **   lfs.lock_dir (path)
13 **   lfs.mkdir (path)
14 **   lfs.rmdir (path)
15 **   lfs.setmode (filepath, mode)
16 **   lfs.symlinkattributes (filepath [, attributename]) -- thanks to Sam Roberts
17 **   lfs.touch (filepath [, atime [, mtime]])
18 **   lfs.unlock (fh)
19 **
20 ** $Id: lfs.c,v 1.61 2009/07/04 02:10:16 mascarenhas Exp $
21 */
22 
23 #ifndef _WIN32
24 #ifndef _AIX
25 #define _FILE_OFFSET_BITS 64 /* Linux, Solaris and HP-UX */
26 #else
27 #define _LARGE_FILES 1 /* AIX */
28 #endif
29 #endif
30 
31 #define _LARGEFILE64_SOURCE
32 
33 #include <errno.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <stdlib.h>
37 #include <time.h>
38 #include <sys/stat.h>
39 
40 #ifdef _WIN32
41 #include <direct.h>
42 #include <windows.h>
43 #include <io.h>
44 #include <sys/locking.h>
45 #ifdef __BORLANDC__
46  #include <utime.h>
47 #else
48  #include <sys/utime.h>
49 #endif
50 #include <fcntl.h>
51 #else
52 #include <unistd.h>
53 #include <dirent.h>
54 #include <fcntl.h>
55 #include <sys/types.h>
56 #include <utime.h>
57 #endif
58 
59 #include "lua.h"
60 #include "lauxlib.h"
61 #include "lualib.h"
62 #include "lfs.h"
63 
64 /* Define 'strerror' for systems that do not implement it */
65 #ifdef NO_STRERROR
66 #define strerror(_)	"System unable to describe the error"
67 #endif
68 
69 /* Define 'getcwd' for systems that do not implement it */
70 #ifdef NO_GETCWD
71 #define getcwd(p,s)	NULL
72 #define getcwd_error	"Function 'getcwd' not provided by system"
73 #else
74 #define getcwd_error	strerror(errno)
75 #endif
76 
77 #define DIR_METATABLE "lfs.directory"
78 #define MAX_DIR_LENGTH 1023
79 typedef struct dir_data {
80 	int  closed;
81 #ifdef _WIN32
82 	long hFile;
83 	char pattern[MAX_DIR_LENGTH+1];
84 #else
85 	DIR *dir;
86 #endif
87 } dir_data;
88 
89 #define LOCK_METATABLE "lfs.lock"
90 
91 #ifdef _WIN32
92  #ifdef __BORLANDC__
93   #define lfs_setmode(L,file,m)   ((void)L, setmode(_fileno(file), m))
94   #define STAT_STRUCT struct stati64
95  #else
96   #define lfs_setmode(L,file,m)   ((void)L, _setmode(_fileno(file), m))
97   #define STAT_STRUCT struct _stati64
98  #endif
99 #define STAT_FUNC _stati64
100 #else
101 #ifndef _O_TEXT
102  #define _O_TEXT               0
103 #endif
104 #ifndef _O_BINARY
105  #define _O_BINARY             0
106 #endif
107 #define lfs_setmode(L,file,m)   ((void)((void)file,m),  \
108 		 luaL_error(L, LUA_QL("setmode") " not supported on this platform"), -1)
109 #define STAT_STRUCT struct stat
110 #define STAT_FUNC stat
111 #define LSTAT_FUNC lstat
112 #endif
113 
114 /*
115 ** This function changes the working (current) directory
116 */
change_dir(lua_State * L)117 static int change_dir (lua_State *L) {
118 	const char *path = luaL_checkstring(L, 1);
119 	if (chdir(path)) {
120 		lua_pushnil (L);
121 		lua_pushfstring (L,"Unable to change working directory to '%s'\n%s\n",
122 				path, chdir_error);
123 		return 2;
124 	} else {
125 		lua_pushboolean (L, 1);
126 		return 1;
127 	}
128 }
129 
130 /*
131 ** This function returns the current directory
132 ** If unable to get the current directory, it returns nil
133 **  and a string describing the error
134 */
135 #ifndef PATH_MAX
136 #define PATH_MAX 4096
137 #endif
138 
get_dir(lua_State * L)139 static int get_dir (lua_State *L) {
140   char path[PATH_MAX];
141   if (getcwd((char *)path, PATH_MAX) == NULL) {
142     lua_pushnil(L);
143     lua_pushstring(L, getcwd_error);
144     return 2;
145   }
146   else {
147     lua_pushstring(L, path);
148     return 1;
149   }
150 }
151 
152 /*
153 ** Check if the given element on the stack is a file and returns it.
154 */
check_file(lua_State * L,int idx,const char * funcname)155 static FILE *check_file (lua_State *L, int idx, const char *funcname) {
156 	FILE **fh = (FILE **)luaL_checkudata (L, idx, "FILE*");
157 	if (fh == NULL) {
158 		luaL_error (L, "%s: not a file", funcname);
159 		return 0;
160 	} else if (*fh == NULL) {
161 		luaL_error (L, "%s: closed file", funcname);
162 		return 0;
163 	} else
164 		return *fh;
165 }
166 
167 
168 /*
169 **
170 */
_file_lock(lua_State * L,FILE * fh,const char * mode,const long start,long len,const char * funcname)171 static int _file_lock (lua_State *L, FILE *fh, const char *mode, const long start, long len, const char *funcname) {
172 	int code;
173 #ifdef _WIN32
174 	/* lkmode valid values are:
175 	   LK_LOCK    Locks the specified bytes. If the bytes cannot be locked, the program immediately tries again after 1 second. If, after 10 attempts, the bytes cannot be locked, the constant returns an error.
176 	   LK_NBLCK   Locks the specified bytes. If the bytes cannot be locked, the constant returns an error.
177 	   LK_NBRLCK  Same as _LK_NBLCK.
178 	   LK_RLCK    Same as _LK_LOCK.
179 	   LK_UNLCK   Unlocks the specified bytes, which must have been previously locked.
180 
181 	   Regions should be locked only briefly and should be unlocked before closing a file or exiting the program.
182 
183 	   http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_crt__locking.asp
184 	*/
185 	int lkmode;
186 	switch (*mode) {
187 		case 'r': lkmode = LK_NBLCK; break;
188 		case 'w': lkmode = LK_NBLCK; break;
189 		case 'u': lkmode = LK_UNLCK; break;
190 		default : return luaL_error (L, "%s: invalid mode", funcname);
191 	}
192 	if (!len) {
193 		fseek (fh, 0L, SEEK_END);
194 		len = ftell (fh);
195 	}
196 	fseek (fh, start, SEEK_SET);
197 #ifdef __BORLANDC__
198 	code = locking (fileno(fh), lkmode, len);
199 #else
200 	code = _locking (fileno(fh), lkmode, len);
201 #endif
202 #else
203 	struct flock f;
204 	switch (*mode) {
205 		case 'w': f.l_type = F_WRLCK; break;
206 		case 'r': f.l_type = F_RDLCK; break;
207 		case 'u': f.l_type = F_UNLCK; break;
208 		default : return luaL_error (L, "%s: invalid mode", funcname);
209 	}
210 	f.l_whence = SEEK_SET;
211 	f.l_start = (off_t)start;
212 	f.l_len = (off_t)len;
213 	code = fcntl (fileno(fh), F_SETLK, &f);
214 #endif
215 	return (code != -1);
216 }
217 
218 #ifdef _WIN32
219 typedef struct lfs_Lock {
220   HANDLE fd;
221 } lfs_Lock;
lfs_lock_dir(lua_State * L)222 static int lfs_lock_dir(lua_State *L) {
223   size_t pathl; HANDLE fd;
224   lfs_Lock *lock;
225   char *ln;
226   const char *lockfile = "/lockfile.lfs";
227   const char *path = luaL_checklstring(L, 1, &pathl);
228   ln = (char*)malloc(pathl + strlen(lockfile) + 1);
229   if(!ln) {
230     lua_pushnil(L); lua_pushstring(L, strerror(errno)); return 2;
231   }
232   strcpy(ln, path); strcat(ln, lockfile);
233   if((fd = CreateFile(ln, GENERIC_WRITE, 0, NULL, CREATE_NEW,
234 	  	FILE_ATTRIBUTE_NORMAL | FILE_FLAG_DELETE_ON_CLOSE, NULL)) == INVALID_HANDLE_VALUE) {
235   	int en = GetLastError();
236   	free(ln); lua_pushnil(L);
237   	if(en == ERROR_FILE_EXISTS || en == ERROR_SHARING_VIOLATION)
238   		lua_pushstring(L, "File exists");
239   	else
240 		lua_pushstring(L, strerror(en));
241 	return 2;
242   }
243   free(ln);
244   lock = (lfs_Lock*)lua_newuserdata(L, sizeof(lfs_Lock));
245   lock->fd = fd;
246   luaL_getmetatable (L, LOCK_METATABLE);
247   lua_setmetatable (L, -2);
248   return 1;
249 }
lfs_unlock_dir(lua_State * L)250 static int lfs_unlock_dir(lua_State *L) {
251   lfs_Lock *lock = luaL_checkudata(L, 1, LOCK_METATABLE);
252   CloseHandle(lock->fd);
253   return 0;
254 }
255 #else
256 typedef struct lfs_Lock {
257   char *ln;
258 } lfs_Lock;
lfs_lock_dir(lua_State * L)259 static int lfs_lock_dir(lua_State *L) {
260   lfs_Lock *lock;
261   size_t pathl;
262   char *ln;
263   const char *lockfile = "/lockfile.lfs";
264   const char *path = luaL_checklstring(L, 1, &pathl);
265   lock = (lfs_Lock*)lua_newuserdata(L, sizeof(lfs_Lock));
266   ln = (char*)malloc(pathl + strlen(lockfile) + 1);
267   if(!ln) {
268     lua_pushnil(L); lua_pushstring(L, strerror(errno)); return 2;
269   }
270   strcpy(ln, path); strcat(ln, lockfile);
271   if(symlink("lock", ln) == -1) {
272     free(ln); lua_pushnil(L);
273     lua_pushstring(L, strerror(errno)); return 2;
274   }
275   lock->ln = ln;
276   luaL_getmetatable (L, LOCK_METATABLE);
277   lua_setmetatable (L, -2);
278   return 1;
279 }
lfs_unlock_dir(lua_State * L)280 static int lfs_unlock_dir(lua_State *L) {
281   lfs_Lock *lock = luaL_checkudata(L, 1, LOCK_METATABLE);
282   if(lock->ln) {
283     unlink(lock->ln);
284     free(lock->ln);
285     lock->ln = NULL;
286   }
287   return 0;
288 }
289 #endif
290 
291 #ifdef _WIN32
lfs_g_setmode(lua_State * L,FILE * f,int arg)292 static int lfs_g_setmode (lua_State *L, FILE *f, int arg) {
293   static const int mode[] = {_O_TEXT, _O_BINARY};
294   static const char *const modenames[] = {"text", "binary", NULL};
295   int op = luaL_checkoption(L, arg, NULL, modenames);
296   int res = lfs_setmode(L, f, mode[op]);
297   if (res != -1) {
298     int i;
299     lua_pushboolean(L, 1);
300     for (i = 0; modenames[i] != NULL; i++) {
301       if (mode[i] == res) {
302         lua_pushstring(L, modenames[i]);
303         goto exit;
304       }
305     }
306     lua_pushnil(L);
307   exit:
308     return 2;
309   } else {
310     int en = errno;
311     lua_pushnil(L);
312     lua_pushfstring(L, "%s", strerror(en));
313     lua_pushinteger(L, en);
314     return 3;
315   }
316 }
317 #else
lfs_g_setmode(lua_State * L,FILE * f,int arg)318 static int lfs_g_setmode (lua_State *L, FILE *f, int arg) {
319   lua_pushboolean(L, 0);
320   lua_pushliteral(L, "setmode not supported on this platform");
321   return 2;
322 }
323 #endif
324 
lfs_f_setmode(lua_State * L)325 static int lfs_f_setmode(lua_State *L) {
326   return lfs_g_setmode(L, check_file(L, 1, "setmode"), 2);
327 }
328 
329 /*
330 ** Locks a file.
331 ** @param #1 File handle.
332 ** @param #2 String with lock mode ('w'rite, 'r'ead).
333 ** @param #3 Number with start position (optional).
334 ** @param #4 Number with length (optional).
335 */
file_lock(lua_State * L)336 static int file_lock (lua_State *L) {
337 	FILE *fh = check_file (L, 1, "lock");
338 	const char *mode = luaL_checkstring (L, 2);
339 	const long start = luaL_optlong (L, 3, 0);
340 	long len = luaL_optlong (L, 4, 0);
341 	if (_file_lock (L, fh, mode, start, len, "lock")) {
342 		lua_pushboolean (L, 1);
343 		return 1;
344 	} else {
345 		lua_pushnil (L);
346 		lua_pushfstring (L, "%s", strerror(errno));
347 		return 2;
348 	}
349 }
350 
351 
352 /*
353 ** Unlocks a file.
354 ** @param #1 File handle.
355 ** @param #2 Number with start position (optional).
356 ** @param #3 Number with length (optional).
357 */
file_unlock(lua_State * L)358 static int file_unlock (lua_State *L) {
359 	FILE *fh = check_file (L, 1, "unlock");
360 	const long start = luaL_optlong (L, 2, 0);
361 	long len = luaL_optlong (L, 3, 0);
362 	if (_file_lock (L, fh, "u", start, len, "unlock")) {
363 		lua_pushboolean (L, 1);
364 		return 1;
365 	} else {
366 		lua_pushnil (L);
367 		lua_pushfstring (L, "%s", strerror(errno));
368 		return 2;
369 	}
370 }
371 
372 
make_dir(lua_State * L)373 static int make_dir (lua_State *L) {
374 	const char *path = luaL_checkstring (L, 1);
375 	int fail;
376 #ifdef _WIN32
377 	int oldmask = umask (0);
378 	fail = _mkdir (path);
379 #else
380 	mode_t oldmask = umask( (mode_t)0 );
381 	fail =  mkdir (path, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP |
382 	                     S_IWGRP | S_IXGRP | S_IROTH | S_IXOTH );
383 #endif
384 	if (fail) {
385 		lua_pushnil (L);
386         lua_pushfstring (L, "%s", strerror(errno));
387 		return 2;
388 	}
389 	umask (oldmask);
390 	lua_pushboolean (L, 1);
391 	return 1;
392 }
393 
394 /*
395 ** Removes a directory.
396 ** @param #1 Directory path.
397 */
remove_dir(lua_State * L)398 static int remove_dir (lua_State *L) {
399 	const char *path = luaL_checkstring (L, 1);
400 	int fail;
401 
402 	fail = rmdir (path);
403 
404 	if (fail) {
405 		lua_pushnil (L);
406 		lua_pushfstring (L, "%s", strerror(errno));
407 		return 2;
408 	}
409 	lua_pushboolean (L, 1);
410 	return 1;
411 }
412 
413 /*
414 ** Directory iterator
415 */
dir_iter(lua_State * L)416 static int dir_iter (lua_State *L) {
417 #ifdef _WIN32
418 	struct _finddata_t c_file;
419 #else
420 	struct dirent *entry;
421 #endif
422 	dir_data *d = (dir_data *)luaL_checkudata (L, 1, DIR_METATABLE);
423 	luaL_argcheck (L, !d->closed, 1, "closed directory");
424 #ifdef _WIN32
425 	if (d->hFile == 0L) { /* first entry */
426 		if ((d->hFile = _findfirst (d->pattern, &c_file)) == -1L) {
427 			lua_pushnil (L);
428 			lua_pushstring (L, strerror (errno));
429 			return 2;
430 		} else {
431 			lua_pushstring (L, c_file.name);
432 			return 1;
433 		}
434 	} else { /* next entry */
435 		if (_findnext (d->hFile, &c_file) == -1L) {
436 			/* no more entries => close directory */
437 			_findclose (d->hFile);
438 			d->closed = 1;
439 			return 0;
440 		} else {
441 			lua_pushstring (L, c_file.name);
442 			return 1;
443 		}
444 	}
445 #else
446 	if ((entry = readdir (d->dir)) != NULL) {
447 		lua_pushstring (L, entry->d_name);
448 		return 1;
449 	} else {
450 		/* no more entries => close directory */
451 		closedir (d->dir);
452 		d->closed = 1;
453 		return 0;
454 	}
455 #endif
456 }
457 
458 
459 /*
460 ** Closes directory iterators
461 */
dir_close(lua_State * L)462 static int dir_close (lua_State *L) {
463 	dir_data *d = (dir_data *)lua_touserdata (L, 1);
464 #ifdef _WIN32
465 	if (!d->closed && d->hFile) {
466 		_findclose (d->hFile);
467 		d->closed = 1;
468 	}
469 #else
470 	if (!d->closed && d->dir) {
471 		closedir (d->dir);
472 		d->closed = 1;
473 	}
474 #endif
475 	return 0;
476 }
477 
478 
479 /*
480 ** Factory of directory iterators
481 */
dir_iter_factory(lua_State * L)482 static int dir_iter_factory (lua_State *L) {
483 	const char *path = luaL_checkstring (L, 1);
484 	dir_data *d;
485 	lua_pushcfunction (L, dir_iter);
486 	d = (dir_data *) lua_newuserdata (L, sizeof(dir_data));
487 	d->closed = 0;
488 #ifdef _WIN32
489 	d->hFile = 0L;
490 	luaL_getmetatable (L, DIR_METATABLE);
491 	lua_setmetatable (L, -2);
492 	if (strlen(path) > MAX_DIR_LENGTH)
493 		luaL_error (L, "path too long: %s", path);
494 	else
495 		sprintf (d->pattern, "%s/*", path);
496 #else
497 	luaL_getmetatable (L, DIR_METATABLE);
498 	lua_setmetatable (L, -2);
499 	d->dir = opendir (path);
500 	if (d->dir == NULL)
501 		luaL_error (L, "cannot open %s: %s", path, strerror (errno));
502 #endif
503 	return 2;
504 }
505 
506 
507 /*
508 ** Creates directory metatable.
509 */
dir_create_meta(lua_State * L)510 static int dir_create_meta (lua_State *L) {
511 	luaL_newmetatable (L, DIR_METATABLE);
512 	/* set its __gc field */
513 	lua_pushstring (L, "__index");
514 	lua_newtable(L);
515 	lua_pushstring (L, "next");
516 	lua_pushcfunction (L, dir_iter);
517 	lua_settable(L, -3);
518 	lua_pushstring (L, "close");
519 	lua_pushcfunction (L, dir_close);
520 	lua_settable(L, -3);
521 	lua_settable (L, -3);
522 	lua_pushstring (L, "__gc");
523 	lua_pushcfunction (L, dir_close);
524 	lua_settable (L, -3);
525 	return 1;
526 }
527 
528 /*
529 ** Creates lock metatable.
530 */
lock_create_meta(lua_State * L)531 static int lock_create_meta (lua_State *L) {
532 	luaL_newmetatable (L, LOCK_METATABLE);
533 	/* set its __gc field */
534 	lua_newtable(L);
535 	lua_pushcfunction(L, lfs_unlock_dir);
536 	lua_setfield(L, -2, "free");
537 	lua_setfield(L, -2, "__index");
538 	lua_pushcfunction(L, lfs_unlock_dir);
539 	lua_setfield(L, -2, "__gc");
540 	return 1;
541 }
542 
543 
544 #ifdef _WIN32
545  #ifndef S_ISDIR
546    #define S_ISDIR(mode)  (mode&_S_IFDIR)
547  #endif
548  #ifndef S_ISREG
549    #define S_ISREG(mode)  (mode&_S_IFREG)
550  #endif
551  #ifndef S_ISLNK
552    #define S_ISLNK(mode)  (0)
553  #endif
554  #ifndef S_ISSOCK
555    #define S_ISSOCK(mode)  (0)
556  #endif
557  #ifndef S_ISFIFO
558    #define S_ISFIFO(mode)  (0)
559  #endif
560  #ifndef S_ISCHR
561    #define S_ISCHR(mode)  (mode&_S_IFCHR)
562  #endif
563  #ifndef S_ISBLK
564    #define S_ISBLK(mode)  (0)
565  #endif
566 #endif
567 /*
568 ** Convert the inode protection mode to a string.
569 */
570 #ifdef _WIN32
mode2string(unsigned short mode)571 static const char *mode2string (unsigned short mode) {
572 #else
573 static const char *mode2string (mode_t mode) {
574 #endif
575   if ( S_ISREG(mode) )
576     return "file";
577   else if ( S_ISDIR(mode) )
578     return "directory";
579   else if ( S_ISLNK(mode) )
580 	return "link";
581   else if ( S_ISSOCK(mode) )
582     return "socket";
583   else if ( S_ISFIFO(mode) )
584 	return "named pipe";
585   else if ( S_ISCHR(mode) )
586 	return "char device";
587   else if ( S_ISBLK(mode) )
588 	return "block device";
589   else
590 	return "other";
591 }
592 
593 
594 /*
595 ** Set access time and modification values for file
596 */
597 static int file_utime (lua_State *L) {
598 	const char *file = luaL_checkstring (L, 1);
599 	struct utimbuf utb, *buf;
600 
601 	if (lua_gettop (L) == 1) /* set to current date/time */
602 		buf = NULL;
603 	else {
604 		utb.actime = (time_t)luaL_optnumber (L, 2, 0);
605 		utb.modtime = (time_t)luaL_optnumber (L, 3, utb.actime);
606 		buf = &utb;
607 	}
608 	if (utime (file, buf)) {
609 		lua_pushnil (L);
610 		lua_pushfstring (L, "%s", strerror (errno));
611 		return 2;
612 	}
613 	lua_pushboolean (L, 1);
614 	return 1;
615 }
616 
617 
618 /* inode protection mode */
619 static void push_st_mode (lua_State *L, STAT_STRUCT *info) {
620 	lua_pushstring (L, mode2string (info->st_mode));
621 }
622 /* device inode resides on */
623 static void push_st_dev (lua_State *L, STAT_STRUCT *info) {
624 	lua_pushnumber (L, (lua_Number)info->st_dev);
625 }
626 /* inode's number */
627 static void push_st_ino (lua_State *L, STAT_STRUCT *info) {
628 	lua_pushnumber (L, (lua_Number)info->st_ino);
629 }
630 /* number of hard links to the file */
631 static void push_st_nlink (lua_State *L, STAT_STRUCT *info) {
632 	lua_pushnumber (L, (lua_Number)info->st_nlink);
633 }
634 /* user-id of owner */
635 static void push_st_uid (lua_State *L, STAT_STRUCT *info) {
636 	lua_pushnumber (L, (lua_Number)info->st_uid);
637 }
638 /* group-id of owner */
639 static void push_st_gid (lua_State *L, STAT_STRUCT *info) {
640 	lua_pushnumber (L, (lua_Number)info->st_gid);
641 }
642 /* device type, for special file inode */
643 static void push_st_rdev (lua_State *L, STAT_STRUCT *info) {
644 	lua_pushnumber (L, (lua_Number)info->st_rdev);
645 }
646 /* time of last access */
647 static void push_st_atime (lua_State *L, STAT_STRUCT *info) {
648 	lua_pushnumber (L, info->st_atime);
649 }
650 /* time of last data modification */
651 static void push_st_mtime (lua_State *L, STAT_STRUCT *info) {
652 	lua_pushnumber (L, info->st_mtime);
653 }
654 /* time of last file status change */
655 static void push_st_ctime (lua_State *L, STAT_STRUCT *info) {
656 	lua_pushnumber (L, info->st_ctime);
657 }
658 /* file size, in bytes */
659 static void push_st_size (lua_State *L, STAT_STRUCT *info) {
660 	lua_pushnumber (L, (lua_Number)info->st_size);
661 }
662 #ifndef _WIN32
663 /* blocks allocated for file */
664 static void push_st_blocks (lua_State *L, STAT_STRUCT *info) {
665 	lua_pushnumber (L, (lua_Number)info->st_blocks);
666 }
667 /* optimal file system I/O blocksize */
668 static void push_st_blksize (lua_State *L, STAT_STRUCT *info) {
669 	lua_pushnumber (L, (lua_Number)info->st_blksize);
670 }
671 #endif
672 static void push_invalid (lua_State *L, STAT_STRUCT *info) {
673   luaL_error(L, "invalid attribute name");
674 #ifndef _WIN32
675   info->st_blksize = 0; /* never reached */
676 #endif
677 }
678 
679  /*
680 ** Convert the inode protection mode to a permission list.
681 */
682 
683 #ifdef _WIN32
684 static const char *perm2string (unsigned short mode) {
685   static char perms[10] = "---------\0";
686   int i;
687   for (i=0;i<9;i++) perms[i]='-';
688   if (mode  & _S_IREAD)
689    { perms[0] = 'r'; perms[3] = 'r'; perms[6] = 'r'; }
690   if (mode  & _S_IWRITE)
691    { perms[1] = 'w'; perms[4] = 'w'; perms[7] = 'w'; }
692   if (mode  & _S_IEXEC)
693    { perms[2] = 'x'; perms[5] = 'x'; perms[8] = 'x'; }
694   return perms;
695 }
696 #else
697 static const char *perm2string (mode_t mode) {
698   static char perms[10] = "---------\0";
699   int i;
700   for (i=0;i<9;i++) perms[i]='-';
701   if (mode & S_IRUSR) perms[0] = 'r';
702   if (mode & S_IWUSR) perms[1] = 'w';
703   if (mode & S_IXUSR) perms[2] = 'x';
704   if (mode & S_IRGRP) perms[3] = 'r';
705   if (mode & S_IWGRP) perms[4] = 'w';
706   if (mode & S_IXGRP) perms[5] = 'x';
707   if (mode & S_IROTH) perms[6] = 'r';
708   if (mode & S_IWOTH) perms[7] = 'w';
709   if (mode & S_IXOTH) perms[8] = 'x';
710   return perms;
711 }
712 #endif
713 
714 /* permssions string */
715 static void push_st_perm (lua_State *L, STAT_STRUCT *info) {
716     lua_pushstring (L, perm2string (info->st_mode));
717 }
718 
719 typedef void (*_push_function) (lua_State *L, STAT_STRUCT *info);
720 
721 struct _stat_members {
722 	const char *name;
723 	_push_function push;
724 };
725 
726 struct _stat_members members[] = {
727 	{ "mode",         push_st_mode },
728 	{ "dev",          push_st_dev },
729 	{ "ino",          push_st_ino },
730 	{ "nlink",        push_st_nlink },
731 	{ "uid",          push_st_uid },
732 	{ "gid",          push_st_gid },
733 	{ "rdev",         push_st_rdev },
734 	{ "access",       push_st_atime },
735 	{ "modification", push_st_mtime },
736 	{ "change",       push_st_ctime },
737 	{ "size",         push_st_size },
738  	{ "permissions",  push_st_perm },
739 #ifndef _WIN32
740 	{ "blocks",       push_st_blocks },
741 	{ "blksize",      push_st_blksize },
742 #endif
743 	{ NULL, push_invalid }
744 };
745 
746 /*
747 ** Get file or symbolic link information
748 */
749 static int _file_info_ (lua_State *L, int (*st)(const char*, STAT_STRUCT*)) {
750 	int i;
751 	STAT_STRUCT info;
752 	const char *file = luaL_checkstring (L, 1);
753 
754 	if (st(file, &info)) {
755 		lua_pushnil (L);
756 		lua_pushfstring (L, "cannot obtain information from file `%s'", file);
757 		return 2;
758 	}
759 	if (lua_isstring (L, 2)) {
760 		int v;
761 		const char *member = lua_tostring (L, 2);
762 		if (strcmp (member, "mode") == 0) v = 0;
763 #ifndef _WIN32
764 		else if (strcmp (member, "blocks")  == 0) v = 11;
765 		else if (strcmp (member, "blksize") == 0) v = 12;
766 #endif
767 		else /* look for member */
768 			for (v = 1; members[v].name; v++)
769 				if (*members[v].name == *member)
770 					break;
771 		/* push member value and return */
772 		members[v].push (L, &info);
773 		return 1;
774 	} else if (!lua_istable (L, 2))
775 		/* creates a table if none is given */
776 		lua_newtable (L);
777 	/* stores all members in table on top of the stack */
778 	for (i = 0; members[i].name; i++) {
779 		lua_pushstring (L, members[i].name);
780 		members[i].push (L, &info);
781 		lua_rawset (L, -3);
782 	}
783 	return 1;
784 }
785 
786 
787 /*
788 ** Get file information using stat.
789 */
790 static int file_info (lua_State *L) {
791 	return _file_info_ (L, STAT_FUNC);
792 }
793 
794 
795 /*
796 ** Get symbolic link information using lstat.
797 */
798 #ifndef _WIN32
799 static int link_info (lua_State *L) {
800 	return _file_info_ (L, LSTAT_FUNC);
801 }
802 #else
803 static int link_info (lua_State *L) {
804   lua_pushboolean(L, 0);
805   lua_pushliteral(L, "symlinkattributes not supported on this platform");
806   return 2;
807 }
808 #endif
809 
810 
811 /*
812 ** Assumes the table is on top of the stack.
813 */
814 static void set_info (lua_State *L) {
815 	lua_pushliteral (L, "_COPYRIGHT");
816 	lua_pushliteral (L, "Copyright (C) 2003-2009 Kepler Project");
817 	lua_settable (L, -3);
818 	lua_pushliteral (L, "_DESCRIPTION");
819 	lua_pushliteral (L, "LuaFileSystem is a Lua library developed to complement the set of functions related to file systems offered by the standard Lua distribution");
820 	lua_settable (L, -3);
821 	lua_pushliteral (L, "_VERSION");
822 	lua_pushliteral (L, "LuaFileSystem 1.5.0");
823 	lua_settable (L, -3);
824 }
825 
826 
827 static const struct luaL_Reg fslib[] = {
828 	{"attributes", file_info},
829 	{"chdir", change_dir},
830 	{"currentdir", get_dir},
831 	{"dir", dir_iter_factory},
832 	{"lock", file_lock},
833 	{"mkdir", make_dir},
834 	{"rmdir", remove_dir},
835 	{"symlinkattributes", link_info},
836 	{"setmode", lfs_f_setmode},
837 	{"touch", file_utime},
838 	{"unlock", file_unlock},
839 	{"lock_dir", lfs_lock_dir},
840 	{NULL, NULL},
841 };
842 
843 int luaopen_lfs (lua_State *L) {
844 	dir_create_meta (L);
845 	lock_create_meta (L);
846 	luaL_register (L, "lfs", fslib);
847 	set_info (L);
848 	return 1;
849 }
850