From fc49cc10ba7e979f02bacacc10c6805c25e43c92 Mon Sep 17 00:00:00 2001
From: Chris Dickens <christopher.a.dickens@gmail.com>
Date: Wed, 5 Jul 2017 15:01:58 -0700
Subject: [PATCH] core: Add provisions for per-context private backend data

This functionality will be useful for backends that need to maintain
data specific to a context.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>
---
 libusb/core.c               | 3 ++-
 libusb/libusbi.h            | 7 +++++++
 libusb/os/haiku_usb_raw.cpp | 1 +
 libusb/os/netbsd_usb.c      | 1 +
 libusb/os/openbsd_usb.c     | 1 +
 libusb/os/wince_usb.c       | 1 +
 libusb/os/windows_usbdk.c   | 1 +
 libusb/os/windows_winusb.c  | 1 +
 libusb/version_nano.h       | 2 +-
 9 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/libusb/core.c b/libusb/core.c
index 38dea8e..06da8d0 100644
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -2050,6 +2050,7 @@ int API_EXPORTED libusb_init(libusb_context **context)
 {
 	struct libusb_device *dev, *next;
 	char *dbg = getenv("LIBUSB_DEBUG");
+	size_t priv_size = usbi_backend.context_priv_size;
 	struct libusb_context *ctx;
 	static int first_init = 1;
 	int r = 0;
@@ -2067,7 +2068,7 @@ int API_EXPORTED libusb_init(libusb_context **context)
 		return 0;
 	}
 
-	ctx = calloc(1, sizeof(*ctx));
+	ctx = calloc(1, sizeof(*ctx) + priv_size);
 	if (!ctx) {
 		r = LIBUSB_ERROR_NO_MEM;
 		goto err_unlock;
diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index bd76111..c820b89 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -358,6 +358,8 @@ struct libusb_context {
 #endif
 
 	struct list_head list;
+
+	PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
 };
 
 enum usbi_event_flags {
@@ -1112,6 +1114,11 @@ struct usbi_os_backend {
 	clockid_t (*get_timerfd_clockid)(void);
 #endif
 
+	/* Number of bytes to reserve for per-context private backend data.
+	 * This private data area is accessible through the "os_priv" field of
+	 * struct libusb_context. */
+	size_t context_priv_size;
+
 	/* Number of bytes to reserve for per-device private backend data.
 	 * This private data area is accessible through the "os_priv" field of
 	 * struct libusb_device. */
diff --git a/libusb/os/haiku_usb_raw.cpp b/libusb/os/haiku_usb_raw.cpp
index a84bd59..f480b2d 100644
--- a/libusb/os/haiku_usb_raw.cpp
+++ b/libusb/os/haiku_usb_raw.cpp
@@ -244,6 +244,7 @@ const struct usbi_os_backend usbi_backend = {
 	/*.get_timerfd_clockid =*/ NULL,
 #endif
 
+	/*.context_priv_size=*/ 0,
 	/*.device_priv_size =*/ sizeof(USBDevice *),
 	/*.device_handle_priv_size =*/ sizeof(USBDeviceHandle *),
 	/*.transfer_priv_size =*/ sizeof(USBTransfer *),
diff --git a/libusb/os/netbsd_usb.c b/libusb/os/netbsd_usb.c
index 26163c0..93a1e22 100644
--- a/libusb/os/netbsd_usb.c
+++ b/libusb/os/netbsd_usb.c
@@ -131,6 +131,7 @@ const struct usbi_os_backend usbi_backend = {
 	netbsd_handle_transfer_completion,
 
 	netbsd_clock_gettime,
+	0,				/* context_priv_size */
 	sizeof(struct device_priv),
 	sizeof(struct handle_priv),
 	0,				/* transfer_priv_size */
diff --git a/libusb/os/openbsd_usb.c b/libusb/os/openbsd_usb.c
index bb75db7..4afa262 100644
--- a/libusb/os/openbsd_usb.c
+++ b/libusb/os/openbsd_usb.c
@@ -134,6 +134,7 @@ const struct usbi_os_backend usbi_backend = {
 	obsd_handle_transfer_completion,
 
 	obsd_clock_gettime,
+	0,				/* context_priv_size */
 	sizeof(struct device_priv),
 	sizeof(struct handle_priv),
 	0,				/* transfer_priv_size */
diff --git a/libusb/os/wince_usb.c b/libusb/os/wince_usb.c
index 39c2da1..a691c9e 100644
--- a/libusb/os/wince_usb.c
+++ b/libusb/os/wince_usb.c
@@ -893,6 +893,7 @@ const struct usbi_os_backend usbi_backend = {
 	NULL,				/* handle_transfer_completion() */
 
 	wince_clock_gettime,
+	0,
 	sizeof(struct wince_device_priv),
 	0,
 	sizeof(struct wince_transfer_priv),
diff --git a/libusb/os/windows_usbdk.c b/libusb/os/windows_usbdk.c
index 6aa7cad..047ce51 100644
--- a/libusb/os/windows_usbdk.c
+++ b/libusb/os/windows_usbdk.c
@@ -893,6 +893,7 @@ const struct usbi_os_backend usbi_backend = {
 #if defined(USBI_TIMERFD_AVAILABLE)
 	NULL,
 #endif
+	0,
 	sizeof(struct usbdk_device_priv),
 	0,
 	sizeof(struct usbdk_transfer_priv),
diff --git a/libusb/os/windows_winusb.c b/libusb/os/windows_winusb.c
index c2559c7..ac360d2 100644
--- a/libusb/os/windows_winusb.c
+++ b/libusb/os/windows_winusb.c
@@ -2095,6 +2095,7 @@ const struct usbi_os_backend usbi_backend = {
 #if defined(USBI_TIMERFD_AVAILABLE)
 	NULL,
 #endif
+	0,
 	sizeof(struct windows_device_priv),
 	sizeof(struct windows_device_handle_priv),
 	sizeof(struct windows_transfer_priv),
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 9821993..d60e39e 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11206
+#define LIBUSB_NANO 11207
-- 
2.7.4