Fix humongous bug with fdopendir on mac

https://opensource.apple.com/source/Libc/Libc-1244.1.7/include/dirent.h.auto.html

ccall picks the wrong one, causes crashes and truncated d_name
entries. Wrapping the function in a small C shim, as well as
using the CAPI, fixes this.
This commit is contained in:
Julian Ospald 2020-04-14 17:07:35 +02:00
parent 06b5a46cf8
commit 74d686547e
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3 changed files with 11 additions and 4 deletions

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@ -1,7 +1,7 @@
#include "dirutils.h"
unsigned int
__posixdir_d_type(struct dirent* d)
{
return(d -> d_type);
}

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@ -7,7 +7,9 @@
#include <sys/stat.h>
#include <fcntl.h>
extern unsigned int
__posixdir_d_type(struct dirent* d)
;
#endif

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@ -10,6 +10,7 @@
-- Traversal and read operations on directories.
{-# LANGUAGE CApiFFI #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE ForeignFunctionInterface #-}
{-# LANGUAGE OverloadedStrings #-}
@ -173,11 +174,15 @@ foreign import ccall unsafe "__hscore_d_name"
foreign import ccall unsafe "__posixdir_d_type"
c_type :: Ptr CDirent -> IO DirType
foreign import ccall "realpath"
foreign import capi "stdlib.h realpath"
c_realpath :: CString -> CString -> IO CString
foreign import ccall unsafe "fdopendir"
c_fdopendir :: Posix.Fd -> IO (Ptr ())
-- Using normal 'ccall' here lead to memory bugs, crashes
-- and corrupted d_name entries. It appears there are two fdopendirs:
-- https://opensource.apple.com/source/Libc/Libc-1244.1.7/include/dirent.h.auto.html
-- The capi call picks the correct one.
foreign import capi unsafe "dirent.h fdopendir"
c_fdopendir :: Posix.Fd -> IO (Ptr CDir)
----------------------------------------------------------
-- less dodgy but still lower-level