libs/core/luasrc/fs.lua

   1 --[[
   2 LuCI - Filesystem tools
   3
   4 Description:
   5 A module offering often needed filesystem manipulation functions
   6
   7 FileId:
   8 $Id$
   9
  10 License:
  11 Copyright 2008 Steven Barth <steven@midlink.org>
  12
  13 Licensed under the Apache License, Version 2.0 (the "License");
  14 you may not use this file except in compliance with the License.
  15 You may obtain a copy of the License at
  16
  17         http://www.apache.org/licenses/LICENSE-2.0
  18
  19 Unless required by applicable law or agreed to in writing, software
  20 distributed under the License is distributed on an "AS IS" BASIS,
  21 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  22 See the License for the specific language governing permissions and
  23 limitations under the License.
  24
  25 ]]--
  26
  27 local io    = require "io"
  28 local os    = require "os"
  29 local ltn12 = require "luci.ltn12"
  30 local posix = require "posix"
  31
  32 local type  = type
  33
  34 --- LuCI filesystem library.
  35 module "luci.fs"
  36
  37 --- Test for file access permission on given path.
  38 -- @class               function
  39 -- @name                access
  40 -- @param str   String value containing the path
  41 -- @return              Number containing the return code, 0 on sucess or nil on error
  42 -- @return              String containing the error description (if any)
  43 -- @return              Number containing the os specific errno (if any)
  44 access = posix.access
  45
  46 --- Evaluate given shell glob pattern and return a table containing all matching
  47 -- file and directory entries.
  48 -- @class                       function
  49 -- @name                        glob
  50 -- @param filename      String containing the path of the file to read
  51 -- @return                      Table containing file and directory entries or nil if no matches
  52 -- @return                      String containing the error description (if no matches)
  53 -- @return                      Number containing the os specific errno (if no matches)
  54 glob = posix.glob
  55
  56 --- Checks wheather the given path exists and points to a regular file.
  57 -- @param filename      String containing the path of the file to test
  58 -- @return                      Boolean indicating wheather given path points to regular file
  59 function isfile(filename)
  60         return posix.stat(filename, "type") == "regular"
  61 end
  62
  63 --- Checks wheather the given path exists and points to a directory.
  64 -- @param dirname       String containing the path of the directory to test
  65 -- @return                      Boolean indicating wheather given path points to directory
  66 function isdirectory(dirname)
  67         return posix.stat(dirname, "type") == "directory"
  68 end
  69
  70 --- Read the whole content of the given file into memory.
  71 -- @param filename      String containing the path of the file to read
  72 -- @return                      String containing the file contents or nil on error
  73 -- @return                      String containing the error message on error
  74 function readfile(filename)
  75         local fp, err = io.open(filename)
  76
  77         if fp == nil then
  78                 return nil, err
  79         end
  80
  81         local data = fp:read("*a")
  82         fp:close()
  83         return data
  84 end
  85
  86 --- Write the contents of given string to given file.
  87 -- @param filename      String containing the path of the file to read
  88 -- @param data          String containing the data to write
  89 -- @return                      Boolean containing true on success or nil on error
  90 -- @return                      String containing the error message on error
  91 function writefile(filename, data)
  92         local fp, err = io.open(filename, "w")
  93
  94         if fp == nil then
  95                 return nil, err
  96         end
  97
  98         fp:write(data)
  99         fp:close()
 100
 101         return true
 102 end
 103
 104 --- Copies a file.
 105 -- @param source        Source file
 106 -- @param dest          Destination
 107 -- @return                      Boolean containing true on success or nil on error
 108 function copy(source, dest)
 109         return ltn12.pump.all(
 110                 ltn12.source.file(io.open(source)),
 111                 ltn12.sink.file(io.open(dest, "w"))
 112         )
 113 end
 114
 115 --- Renames a file.
 116 -- @param source        Source file
 117 -- @param dest          Destination
 118 -- @return                      Boolean containing true on success or nil on error
 119 function rename(source, dest)
 120         local stat, err, code = os.rename(source, dest)
 121         if code == 18 then
 122                 stat, err, code = copy(source, dest)
 123                 if stat then
 124                         stat, err, code = unlink(source)
 125                 end
 126         end
 127         return stat, err, code
 128 end
 129
 130 --- Get the last modification time of given file path in Unix epoch format.
 131 -- @param path  String containing the path of the file or directory to read
 132 -- @return              Number containing the epoch time or nil on error
 133 -- @return              String containing the error description (if any)
 134 -- @return              Number containing the os specific errno (if any)
 135 function mtime(path)
 136         return posix.stat(path, "mtime")
 137 end
 138
 139 --- Return the last element - usually the filename - from the given path with
 140 -- the directory component stripped.
 141 -- @class               function
 142 -- @name                basename
 143 -- @param path  String containing the path to strip
 144 -- @return              String containing the base name of given path
 145 -- @see                 dirname
 146 basename = posix.basename
 147
 148 --- Return the directory component of the given path with the last element
 149 -- stripped of.
 150 -- @class               function
 151 -- @name                dirname
 152 -- @param path  String containing the path to strip
 153 -- @return              String containing the directory component of given path
 154 -- @see                 basename
 155 dirname = posix.dirname
 156
 157 --- Return a table containing all entries of the specified directory.
 158 -- @class               function
 159 -- @name                dir
 160 -- @param path  String containing the path of the directory to scan
 161 -- @return              Table containing file and directory entries or nil on error
 162 -- @return              String containing the error description on error
 163 -- @return              Number containing the os specific errno on error
 164 dir = posix.dir
 165
 166 --- Create a new directory, recursively on demand.
 167 -- @param path          String with the name or path of the directory to create
 168 -- @param recursive     Create multiple directory levels (optional, default is true)
 169 -- @return                      Number with the return code, 0 on sucess or nil on error
 170 -- @return                      String containing the error description on error
 171 -- @return                      Number containing the os specific errno on error
 172 function mkdir(path, recursive)
 173         if recursive then
 174                 local base = "."
 175
 176                 if path:sub(1,1) == "/" then
 177                         base = ""
 178                         path = path:gsub("^/+","")
 179                 end
 180
 181                 for elem in path:gmatch("([^/]+)/*") do
 182                         base = base .. "/" .. elem
 183
 184                         local stat = posix.stat( base )
 185
 186                         if not stat then
 187                                 local stat, errmsg, errno = posix.mkdir( base )
 188
 189                                 if type(stat) ~= "number" or stat ~= 0 then
 190                                         return stat, errmsg, errno
 191                                 end
 192                         else
 193                                 if stat.type ~= "directory" then
 194                                         return nil, base .. ": File exists", 17
 195                                 end
 196                         end
 197                 end
 198
 199                 return 0
 200         else
 201                 return posix.mkdir( path )
 202         end
 203 end
 204
 205 --- Remove the given empty directory.
 206 -- @class               function
 207 -- @name                rmdir
 208 -- @param path  String containing the path of the directory to remove
 209 -- @return              Number with the return code, 0 on sucess or nil on error
 210 -- @return              String containing the error description on error
 211 -- @return              Number containing the os specific errno on error
 212 rmdir = posix.rmdir
 213
 214 --- Get information about given file or directory.
 215 -- @class               function
 216 -- @name                stat
 217 -- @param path  String containing the path of the directory to query
 218 -- @return              Table containing file or directory properties or nil on error
 219 -- @return              String containing the error description on error
 220 -- @return              Number containing the os specific errno on error
 221 stat = posix.stat
 222
 223 --- Set permissions on given file or directory.
 224 -- @class               function
 225 -- @name                chmod
 226 -- @param path  String containing the path of the directory
 227 -- @param perm  String containing the permissions to set ([ugoa][+-][rwx])
 228 -- @return              Number with the return code, 0 on sucess or nil on error
 229 -- @return              String containing the error description on error
 230 -- @return              Number containing the os specific errno on error
 231 chmod = posix.chmod
 232
 233 --- Create a hard- or symlink from given file (or directory) to specified target
 234 -- file (or directory) path.
 235 -- @class                       function
 236 -- @name                        link
 237 -- @param path1         String containing the source path to link
 238 -- @param path2         String containing the destination path for the link
 239 -- @param symlink       Boolean indicating wheather to create a symlink (optional)
 240 -- @return                      Number with the return code, 0 on sucess or nil on error
 241 -- @return                      String containing the error description on error
 242 -- @return                      Number containing the os specific errno on error
 243 link = posix.link
 244
 245 --- Remove the given file.
 246 -- @class               function
 247 -- @name                unlink
 248 -- @param path  String containing the path of the file to remove
 249 -- @return              Number with the return code, 0 on sucess or nil on error
 250 -- @return              String containing the error description on error
 251 -- @return              Number containing the os specific errno on error
 252 unlink = posix.unlink
 253
 254 --- Retrieve target of given symlink.
 255 -- @class               function
 256 -- @name                readlink
 257 -- @param path  String containing the path of the symlink to read
 258 -- @return              String containing the link target or nil on error
 259 -- @return              String containing the error description on error
 260 -- @return              Number containing the os specific errno on error
 261 readlink = posix.readlink