Indirectly free(3) buffers in fshutdown(3).

libc/include/FILE.h

@@ -86,6 +86,7 @@ struct FILE
 	void (*free_func)(void* free_user, struct FILE* fp);
 	/* Application writers shouldn't use anything beyond this point. */
 	pthread_mutex_t file_lock;
+	void (*buffer_free_indirect)(void*);
 	struct FILE* prev;
 	struct FILE* next;
 	int flags;

libc/stdio/fsetdefaultbuf_unlocked.cpp

@@ -66,5 +66,7 @@ extern "C" int fsetdefaultbuf_unlocked(FILE* fp)
 
 	// The buffer now belongs to the FILE.
 	fp->flags |= _FILE_BUFFER_OWNED;
+	fp->buffer_free_indirect = free;
+
 	return 0;
 }

libc/stdio/fshutdown.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2013.
+    Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
 
     This file is part of the Sortix C Library.
 
@@ -34,8 +34,8 @@ extern "C" int fshutdown(FILE* fp)
 		         exact error value, for instance, as with popen/pclose. */;
 	}
 	ret = fp->close_func ? fp->close_func(fp->user) : ret;
-	if ( fp->flags & _FILE_BUFFER_OWNED )
-		free(fp->buffer);
+	if ( fp->flags & _FILE_BUFFER_OWNED && fp->buffer_free_indirect )
+		fp->buffer_free_indirect(fp->buffer);
 	// Resetting the FILE here isn't needed in the case where fclose calls us,
 	// but it's nice to zero it out anyway (avoiding state) data, and it's a
 	// feature when called by freopen that wishes to reuse the FILE. It also