tls: avoid unnecessary changes to POSIX build, part 2

On reflection, the previous commit may have been ill-advised.  There
are many calls to open_read_close() and most shouldn't be able to
access special devices.  (Though in practice only a few are enabled
in busybox-w32.)

Nonetheless, I've implemented a new mechanism which uses the macro
MINGW_SPECIAL() to mark calls to functions that are allowed to
access special devices.

An unrelated change is to avoid compiling fputs_stdout() in
coreutils/printf.c for the POSIX build.

2 files changed, 7 insertions, 0 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 3d6a6a0cf..a7f32e21e 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -202,6 +202,9 @@ int klogctl(int type, char *b, int len);
 
 #if ENABLE_PLATFORM_MINGW32
 # include "mingw.h"
+# define MINGW_SPECIAL(a) mingw_ ## a
+#else
+# define MINGW_SPECIAL(a) a
 #endif
 
 /* Busybox does not use threads, we can speed up stdio. */
diff --git a/include/mingw.h b/include/mingw.h
index d1e638231..a1ba5f5af 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -429,7 +429,11 @@ enum {DEV_NULL, DEV_ZERO, DEV_URANDOM, NOT_DEVICE = -1};
 int get_dev_type(const char *filename);
 void update_dev_fd(int dev, int fd);
 int mingw_open (const char *filename, int oflags, ...);
+
+/* functions which add O_SPECIAL to open(2) to allow access to devices */
 int mingw_xopen(const char *filename, int oflags);
+ssize_t mingw_open_read_close(const char *fn, void *buf, size_t size) FAST_FUNC;
+
 ssize_t mingw_read(int fd, void *buf, size_t count);
 int mingw_close(int fd);
 int pipe(int filedes[2]);