From e4a29888cb52c1eafd3ab57a6e220b38147ecfbe Mon Sep 17 00:00:00 2001
From: Etienne Cordonnier <ecordonnier@snap.com>
Date: Tue, 14 Mar 2023 13:39:23 +0100
Subject: [PATCH] adb: Fix build on big endian systems

The usb_linux_client.c file defines cpu_to_le16/32 by using the C
library htole16/32 function calls. However, cpu_to_le16/32 are used
when initializing structures, i.e in a context where a function call
is not allowed.

It works fine on little endian systems because htole16/32 are defined
by the C library as no-ops. But on big-endian systems, they are
actually doing something, which might involve calling a function,
causing build failures.

To solve this, we simply open-code cpu_to_le16/32 in a way that allows
them to be used when initializing structures.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[Forward-ported to version 29]
Signed-off-by: Etienne Cordonnier <ecordonnier@snap.com>

---
Upstream-Status: Pending

 system/core/adb/daemon/usb_ffs.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/system/core/adb/daemon/usb_ffs.cpp b/system/core/adb/daemon/usb_ffs.cpp
index b19fa5d5..ef2291ca 100644
--- a/system/core/adb/daemon/usb_ffs.cpp
+++ b/system/core/adb/daemon/usb_ffs.cpp
@@ -39,8 +39,15 @@
 
 #define USB_EXT_PROP_UNICODE 1
 
-#define cpu_to_le16(x) htole16(x)
-#define cpu_to_le32(x) htole32(x)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+# define cpu_to_le16(x) (x)
+# define cpu_to_le32(x) (x)
+#else
+# define cpu_to_le16(x) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
+# define cpu_to_le32(x) \
+	((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) | \
+	 (((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))
+#endif
 
 // clang-format off
 struct func_desc {
