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freebsd/stand/liblua/lfs.c
Conrad Meyer f2b32f473e Lua lfs.attributes: Provide a more consistent error return
In the remaining error case, return a 3-tuple consistent with the other
error return case.

Document how to invoke lfs.attributes() and detect/decode error return in
example comments.

Reviewed by:	kevans
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14451
2018-02-20 18:21:30 +00:00

343 lines
8.2 KiB
C

/*-
* Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Portions derived from https://github.com/keplerproject/luafilesystem under
* the terms of the MIT license:
*
* Copyright (c) 2003-2014 Kepler Project.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <lua.h>
#include "lauxlib.h"
#include "lfs.h"
#include "lstd.h"
#include "lutils.h"
#include "bootstrap.h"
#ifndef nitems
#define nitems(x) (sizeof((x)) / sizeof((x)[0]))
#endif
/*
* The goal is to emulate a subset of the upstream Lua FileSystem library, as
* faithfully as possible in the boot environment. Only APIs that seem useful
* need to emulated.
*
* Example usage:
*
* for file in lfs.dir("/boot") do
* print("\t"..file)
* end
*
* Prints:
* .
* ..
* (etc.)
*
* The other available API is lfs.attributes(), which functions somewhat like
* stat(2) and returns a table of values. Example code:
*
* attrs, errormsg, errorcode = lfs.attributes("/boot")
* if attrs == nil then
* print(errormsg)
* return errorcode
* end
*
* for k, v in pairs(attrs) do
* print(k .. ":\t" .. v)
* end
* return 0
*
* Prints (on success):
* gid: 0
* change: 140737488342640
* mode: directory
* rdev: 0
* ino: 4199275
* dev: 140737488342544
* modification: 140737488342576
* size: 512
* access: 140737488342560
* permissions: 755
* nlink: 58283552
* uid: 1001
*/
#define DIR_METATABLE "directory iterator metatable"
static int
lua_dir_iter_next(lua_State *L)
{
struct dirent *entry;
DIR *dp, **dpp;
dpp = (DIR **)luaL_checkudata(L, 1, DIR_METATABLE);
dp = *dpp;
luaL_argcheck(L, dp != NULL, 1, "closed directory");
entry = readdirfd(dp->fd);
if (entry == NULL) {
closedir(dp);
*dpp = NULL;
return 0;
}
lua_pushstring(L, entry->d_name);
return 1;
}
static int
lua_dir_iter_close(lua_State *L)
{
DIR *dp, **dpp;
dpp = (DIR **)lua_touserdata(L, 1);
dp = *dpp;
if (dp == NULL)
return 0;
closedir(dp);
*dpp = NULL;
return 0;
}
static int
lua_dir(lua_State *L)
{
const char *path;
DIR *dp;
if (lua_gettop(L) != 1) {
lua_pushnil(L);
return 1;
}
path = luaL_checkstring(L, 1);
dp = opendir(path);
if (dp == NULL) {
lua_pushnil(L);
return 1;
}
lua_pushcfunction(L, lua_dir_iter_next);
*(DIR **)lua_newuserdata(L, sizeof(DIR **)) = dp;
luaL_getmetatable(L, DIR_METATABLE);
lua_setmetatable(L, -2);
return 2;
}
static void
register_metatable(lua_State *L)
{
/*
* Create so-called metatable for iterator object returned by
* lfs.dir().
*/
luaL_newmetatable(L, DIR_METATABLE);
lua_newtable(L);
lua_pushcfunction(L, lua_dir_iter_next);
lua_setfield(L, -2, "next");
lua_pushcfunction(L, lua_dir_iter_close);
lua_setfield(L, -2, "close");
/* Magically associate anonymous method table with metatable. */
lua_setfield(L, -2, "__index");
/* Implement magic destructor method */
lua_pushcfunction(L, lua_dir_iter_close);
lua_setfield(L, -2, "__gc");
lua_pop(L, 1);
}
#define PUSH_INTEGER(lname, stname) \
static void \
push_st_ ## lname (lua_State *L, struct stat *sb) \
{ \
lua_pushinteger(L, (lua_Integer)sb->st_ ## stname); \
}
PUSH_INTEGER(dev, dev)
PUSH_INTEGER(ino, ino)
PUSH_INTEGER(nlink, nlink)
PUSH_INTEGER(uid, uid)
PUSH_INTEGER(gid, gid)
PUSH_INTEGER(rdev, rdev)
PUSH_INTEGER(access, atime)
PUSH_INTEGER(modification, mtime)
PUSH_INTEGER(change, ctime)
PUSH_INTEGER(size, size)
#undef PUSH_INTEGER
static void
push_st_mode(lua_State *L, struct stat *sb)
{
const char *mode_s;
mode_t mode;
mode = (sb->st_mode & S_IFMT);
if (S_ISREG(mode))
mode_s = "file";
else if (S_ISDIR(mode))
mode_s = "directory";
else if (S_ISLNK(mode))
mode_s = "link";
else if (S_ISSOCK(mode))
mode_s = "socket";
else if (S_ISFIFO(mode))
mode_s = "fifo";
else if (S_ISCHR(mode))
mode_s = "char device";
else if (S_ISBLK(mode))
mode_s = "block device";
else
mode_s = "other";
lua_pushstring(L, mode_s);
}
static void
push_st_permissions(lua_State *L, struct stat *sb)
{
char buf[20];
/*
* XXX
* Could actually format as "-rwxrwxrwx" -- do we care?
*/
snprintf(buf, sizeof(buf), "%o", sb->st_mode & ~S_IFMT);
lua_pushstring(L, buf);
}
#define PUSH_ENTRY(n) { #n, push_st_ ## n }
struct stat_members {
const char *name;
void (*push)(lua_State *, struct stat *);
} members[] = {
PUSH_ENTRY(mode),
PUSH_ENTRY(dev),
PUSH_ENTRY(ino),
PUSH_ENTRY(nlink),
PUSH_ENTRY(uid),
PUSH_ENTRY(gid),
PUSH_ENTRY(rdev),
PUSH_ENTRY(access),
PUSH_ENTRY(modification),
PUSH_ENTRY(change),
PUSH_ENTRY(size),
PUSH_ENTRY(permissions),
};
#undef PUSH_ENTRY
static int
lua_attributes(lua_State *L)
{
struct stat sb;
const char *path, *member;
size_t i;
int rc;
path = luaL_checkstring(L, 1);
if (path == NULL) {
lua_pushnil(L);
lua_pushfstring(L, "cannot convert first argument to string");
lua_pushinteger(L, EINVAL);
return 3;
}
rc = stat(path, &sb);
if (rc != 0) {
lua_pushnil(L);
lua_pushfstring(L,
"cannot obtain information from file '%s': %s", path,
strerror(errno));
lua_pushinteger(L, errno);
return 3;
}
if (lua_isstring(L, 2)) {
member = lua_tostring(L, 2);
for (i = 0; i < nitems(members); i++) {
if (strcmp(members[i].name, member) != 0)
continue;
members[i].push(L, &sb);
return 1;
}
return luaL_error(L, "invalid attribute name '%s'", member);
}
/* Create or reuse existing table */
lua_settop(L, 2);
if (!lua_istable(L, 2))
lua_newtable(L);
/* Export all stat data to caller */
for (i = 0; i < nitems(members); i++) {
lua_pushstring(L, members[i].name);
members[i].push(L, &sb);
lua_rawset(L, -3);
}
return 1;
}
#define REG_SIMPLE(n) { #n, lua_ ## n }
static const struct luaL_Reg fslib[] = {
REG_SIMPLE(attributes),
REG_SIMPLE(dir),
{ NULL, NULL },
};
#undef REG_SIMPLE
int
luaopen_lfs(lua_State *L)
{
register_metatable(L);
luaL_newlib(L, fslib);
return 1;
}