From eb0c2bbbaf0722103124a589e3dfe952c2664cbb Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Mon, 25 Jan 2021 13:57:08 +0000
Subject: 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.
---
 coreutils/dd.c     | 6 ++----
 coreutils/printf.c | 2 ++
 coreutils/shred.c  | 8 ++------
 include/libbb.h    | 3 +++
 include/mingw.h    | 4 ++++
 libbb/read.c       | 7 -------
 networking/tls.c   | 2 +-
 win32/mingw.c      | 9 +++++++++
 8 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/coreutils/dd.c b/coreutils/dd.c
index c150ef5bc..bd799aa2b 100644
--- a/coreutils/dd.c
+++ b/coreutils/dd.c
@@ -505,10 +505,8 @@ int dd_main(int argc UNUSED_PARAM, char **argv)
 		if (G.flags & FLAG_IDIRECT)
 			iflag |= O_DIRECT;
 #endif
-#if !ENABLE_PLATFORM_MINGW32
-		xmove_fd(xopen(infile, iflag), ifd);
-#else
-		xmove_fd(mingw_xopen(infile, iflag), ifd);
+		xmove_fd(MINGW_SPECIAL(xopen)(infile, iflag), ifd);
+#if ENABLE_PLATFORM_MINGW32
 		update_dev_fd(get_dev_type(infile), ifd);
 #endif
 	} else {
diff --git a/coreutils/printf.c b/coreutils/printf.c
index aabc51e0d..d1d22f39c 100644
--- a/coreutils/printf.c
+++ b/coreutils/printf.c
@@ -151,10 +151,12 @@ static double my_xstrtod(const char *arg)
 	return result;
 }
 
+#if ENABLE_PLATFORM_MINGW32
 static int fputs_stdout(const char *s)
 {
 	return fputs(s, stdout);
 }
+#endif
 
 /* Handles %b; return 1 if output is to be short-circuited by \c */
 static int print_esc_string(const char *str)
diff --git a/coreutils/shred.c b/coreutils/shred.c
index 86d4b66b4..0b11b9491 100644
--- a/coreutils/shred.c
+++ b/coreutils/shred.c
@@ -38,10 +38,6 @@
 
 #include "libbb.h"
 
-#if ENABLE_PLATFORM_MINGW32
-#define xopen mingw_xopen
-#endif
-
 int shred_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int shred_main(int argc UNUSED_PARAM, char **argv)
 {
@@ -61,9 +57,9 @@ int shred_main(int argc UNUSED_PARAM, char **argv)
 	opt = getopt32(argv, "fuzn:+vx", &num_iter);
 	argv += optind;
 
-	zero_fd = xopen("/dev/zero", O_RDONLY);
+	zero_fd = MINGW_SPECIAL(xopen)("/dev/zero", O_RDONLY);
 	if (num_iter != 0)
-		rand_fd = xopen("/dev/urandom", O_RDONLY);
+		rand_fd = MINGW_SPECIAL(xopen)("/dev/urandom", O_RDONLY);
 
 	if (!*argv)
 		bb_show_usage();
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]);
diff --git a/libbb/read.c b/libbb/read.c
index 2e4317cd5..a342506a8 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -73,14 +73,7 @@ ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size)
 
 ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size)
 {
-#if !ENABLE_PLATFORM_MINGW32
 	int fd = open(filename, O_RDONLY);
-#else
-	int fd, flag;
-
-	flag = O_RDONLY | (get_dev_type(filename) == DEV_URANDOM ? O_SPECIAL : 0);
-	fd = mingw_open(filename, flag);
-#endif
 	if (fd < 0)
 		return fd;
 	return read_close(fd, buf, size);
diff --git a/networking/tls.c b/networking/tls.c
index e34acd69f..b05afe1c9 100644
--- a/networking/tls.c
+++ b/networking/tls.c
@@ -349,7 +349,7 @@ static void dump_tls_record(const void *vp, int len)
 
 void FAST_FUNC tls_get_random(void *buf, unsigned len)
 {
-	if (len != open_read_close("/dev/urandom", buf, len))
+	if (len != MINGW_SPECIAL(open_read_close)("/dev/urandom", buf, len))
 		xfunc_die();
 }
 
diff --git a/win32/mingw.c b/win32/mingw.c
index ed0989be2..474d9cdc6 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -229,6 +229,15 @@ int mingw_xopen(const char *pathname, int flags)
 	return ret;
 }
 
+ssize_t FAST_FUNC mingw_open_read_close(const char *fn, void *buf, size_t size)
+{
+	/* allow use of special devices */
+	int fd = mingw_open(fn, O_RDONLY|O_SPECIAL);
+	if (fd < 0)
+		return fd;
+	return read_close(fd, buf, size);
+}
+
 #undef fopen
 FILE *mingw_fopen (const char *filename, const char *otype)
 {
-- 
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