Simple implementation of chmod(path, mode)

currently only integer modes, can do string modes like +x later
fixes JuliaLang#7574

base/exports.jl

@@ -1237,6 +1237,7 @@ export
 
 # filesystem operations
  cd,
+ chmod,
  cp,
  ctime,
  download,

base/fs.jl

@@ -23,6 +23,7 @@ export File,
  rename,
  sendfile,
  symlink,
+ chmod,
  JL_O_WRONLY,
  JL_O_RDONLY,
  JL_O_RDWR,
@@ -162,6 +163,11 @@ end
 @windowsxp_only symlink(p::String, np::String) = 
  error("WindowsXP does not support soft symlinks")
 
+function chmod(p::String, mode::Integer)
+ err = ccall(:jl_fs_chmod, Int32, (Ptr{Uint8}, Cint), p, mode)
+ uv_error("chmod",err)
+end
+
 function write(f::File, buf::Ptr{Uint8}, len::Integer, offset::Integer=-1)
  if !f.open
  error("file is not open")

doc/stdlib/base.rst

@@ -5279,6 +5279,11 @@ System
  This function raises an error under operating systems that do not support
  soft symbolic links, such as Windows XP.
 
+.. function:: chmod(path, mode)
+
+ Change the permissions mode of ``path`` to ``mode``. Only integer ``mode``s
+ (e.g. 0o777) are currently supported.
+
 .. function:: getpid() -> Int32
 
  Get julia's process ID.

src/jl_uv.c

@@ -442,6 +442,14 @@ DLLEXPORT int jl_fs_symlink(char *path, char *new_path, int flags)
  return ret;
 }
 
+DLLEXPORT int jl_fs_chmod(char *path, int mode)
+{
+ uv_fs_t req;
+ int ret = uv_fs_chmod(jl_io_loop, &req, path, mode, NULL);
+ uv_fs_req_cleanup(&req);
+ return ret;
+}
+
 DLLEXPORT int jl_fs_write(int handle, char *data, size_t len, size_t offset)
 {
  uv_fs_t req;

test/file.jl

@@ -28,10 +28,9 @@ end
 @test !islink(file)
 @test isreadable(file)
 @test iswritable(file)
-# Here's something else that might be UNIX-specific?
-run(`chmod -w $file`)
+chmod(file, filemode(file) & 0o7555)
 @test !iswritable(file)
-run(`chmod +w $file`)
+chmod(file, filemode(file) | 0o222)
 @test !isexecutable(file)
 @test filesize(file) == 0
 # On windows the filesize of a folder is the accumulation of all the contained