From 5f0cc26af63c811143975061ada9af4093a3f95e Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dtor@chromium.org>
Date: Tue, 4 Jun 2019 12:51:45 -0700
Subject: [PATCH 06/11] CHROMIUM: linux_usbfs: tease apart
 linux_device_address()

The function has become a kitchen sink and hard to follow, let's split
it apart so we can call individual parts, as needed.

Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
---
 libusb/os/linux_udev.c  |   2 +-
 libusb/os/linux_usbfs.c | 121 +++++++++++++++++++++++++---------------
 libusb/os/linux_usbfs.h |   2 +-
 3 files changed, 78 insertions(+), 47 deletions(-)

diff --git a/libusb/os/linux_udev.c b/libusb/os/linux_udev.c
index bea03e3..c97806b 100644
--- a/libusb/os/linux_udev.c
+++ b/libusb/os/linux_udev.c
@@ -232,7 +232,7 @@ static int udev_device_info(struct libusb_context *ctx, int detached,
 	}
 
 	return linux_get_device_address(ctx, detached, busnum, devaddr,
-					dev_node, *sys_name, -1);
+					dev_node, *sys_name);
 }
 
 static void udev_hotplug_event(struct udev_device* udev_dev)
diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
index 2e7add4..b55b86d 100644
--- a/libusb/os/linux_usbfs.c
+++ b/libusb/os/linux_usbfs.c
@@ -686,40 +686,13 @@ static int sysfs_get_active_config(struct libusb_device *dev, int *config)
 	return 0;
 }
 
-int linux_get_device_address (struct libusb_context *ctx, int detached,
-	uint8_t *busnum, uint8_t *devaddr,const char *dev_node,
-	const char *sys_name, int fd)
+static int device_address_from_sysfs(struct libusb_context *ctx,
+	const char *sys_name, uint8_t *busnum, uint8_t *devaddr)
 {
-	char proc_path[PATH_MAX], fd_path[PATH_MAX];
 	int sysfs_attr;
-	ssize_t r;
-
-	usbi_dbg("getting address for device: %s detached: %d", sys_name, detached);
-	/* can't use sysfs to read the bus and device number if the
-	 * device has been detached */
-	if (!sysfs_can_relate_devices || detached || NULL == sys_name) {
-		if (NULL == dev_node && fd >= 0) {
-			/* try to retrieve the device node from fd */
-			snprintf(proc_path, PATH_MAX, "/proc/self/fd/%d", fd);
-			r = readlink(proc_path, fd_path, PATH_MAX);
-			if (r > 0)
-				dev_node = fd_path;
-		}
-		if (NULL == dev_node) {
-			return LIBUSB_ERROR_OTHER;
-		}
 
-		/* will this work with all supported kernel versions? */
-		if (!strncmp(dev_node, "/dev/bus/usb", 12)) {
-			sscanf (dev_node, "/dev/bus/usb/%hhu/%hhu", busnum, devaddr);
-		} else if (!strncmp(dev_node, "/proc/bus/usb", 13)) {
-			sscanf (dev_node, "/proc/bus/usb/%hhu/%hhu", busnum, devaddr);
-		} else {
-			return LIBUSB_ERROR_OTHER;
-		}
-
-		return LIBUSB_SUCCESS;
-	}
+	if (!sysfs_can_relate_devices || NULL == sys_name)
+		return LIBUSB_ERROR_OTHER;
 
 	usbi_dbg("scan %s", sys_name);
 
@@ -743,6 +716,74 @@ int linux_get_device_address (struct libusb_context *ctx, int detached,
 	return LIBUSB_SUCCESS;
 }
 
+static int device_address_from_path(struct libusb_context *ctx,
+	const char *path, uint8_t *busnum, uint8_t *devaddr)
+{
+	int ret = 0;
+
+	if (NULL == path)
+		return LIBUSB_ERROR_OTHER;
+
+	/* will this work with all supported kernel versions? */
+	if (!strncmp(path, "/dev/bus/usb", 12)) {
+		ret = sscanf(path, "/dev/bus/usb/%hhu/%hhu", busnum, devaddr);
+	} else if (!strncmp(path, "/proc/bus/usb", 13)) {
+		ret = sscanf(path, "/proc/bus/usb/%hhu/%hhu", busnum, devaddr);
+	}
+
+	return ret == 2 ? LIBUSB_SUCCESS : LIBUSB_ERROR_OTHER;
+}
+
+static int device_address_from_fd(struct libusb_context *ctx,
+	int fd, uint8_t *busnum, uint8_t *devaddr)
+{
+	struct usbfs_connectinfo ci;
+	char proc_path[PATH_MAX], fd_path[PATH_MAX];
+	ssize_t r;
+	int ret;
+
+	/* Try to see if we can deduce the address from file our
+	 * file descriptor points to.
+	 */
+	snprintf(proc_path, PATH_MAX, "/proc/self/fd/%d", fd);
+	r = readlink(proc_path, fd_path, PATH_MAX);
+	if (r > 0) {
+		ret = device_address_from_path(ctx, fd_path, busnum, devaddr);
+		if (ret == LIBUSB_SUCCESS)
+			return ret;
+	}
+
+	ret = ioctl(fd, IOCTL_USBFS_CONNECTINFO, &ci);
+	if (ret < 0) {
+		usbi_err(ctx, "connectinfo failed (%d)", errno);
+		return LIBUSB_ERROR_IO;
+	}
+
+	/* IOCTL_USBFS_CONNECTINFO does not return the bus number.
+	 * We choose 0 here as linux starts numbering buses from 1. */
+	*busnum = 0;
+	*devaddr = ci.devnum;
+
+	return LIBUSB_SUCCESS;
+}
+
+int linux_get_device_address(struct libusb_context *ctx, int detached,
+	uint8_t *busnum, uint8_t *devaddr,const char *dev_node,
+	const char *sys_name)
+{
+	usbi_dbg("getting address for device: %s detached: %d", sys_name, detached);
+	/* can't use sysfs to read the bus and device number if the
+	 * device has been detached */
+	if (!sysfs_can_relate_devices || detached) {
+		if (dev_node)
+			return device_address_from_path(ctx, dev_node,
+							busnum, devaddr);
+		return LIBUSB_ERROR_OTHER;
+	}
+
+	return device_address_from_sysfs(ctx, sys_name, busnum, devaddr);
+}
+
 /* Return offset of the next descriptor with the given type */
 static int seek_to_next_descriptor(struct libusb_context *ctx,
 	uint8_t descriptor_type, unsigned char *buffer, int size)
@@ -1314,7 +1355,7 @@ static int sysfs_scan_device(struct libusb_context *ctx, const char *devname)
 	uint8_t busnum, devaddr;
 	int ret;
 
-	ret = linux_get_device_address (ctx, 0, &busnum, &devaddr, NULL, devname, -1);
+	ret = device_address_from_sysfs(ctx, devname, &busnum, &devaddr);
 	if (LIBUSB_SUCCESS != ret) {
 		return ret;
 	}
@@ -1408,22 +1449,12 @@ static int op_wrap_sys_device(struct libusb_context *ctx,
 	struct linux_device_handle_priv *hpriv = _device_handle_priv(handle);
 	int fd = (int)sys_dev;
 	uint8_t busnum, devaddr;
-	struct usbfs_connectinfo ci;
 	struct libusb_device *dev;
 	int r;
 
-	r = linux_get_device_address(ctx, 1, &busnum, &devaddr, NULL, NULL, fd);
-	if (r < 0) {
-		r = ioctl(fd, IOCTL_USBFS_CONNECTINFO, &ci);
-		if (r < 0) {
-			usbi_err(ctx, "connectinfo failed (%d)", errno);
-			return LIBUSB_ERROR_IO;
-		}
-		/* There is no ioctl to get the bus number. We choose 0 here
-		 * as linux starts numbering buses from 1. */
-		busnum = 0;
-		devaddr = ci.devnum;
-	}
+	r = device_address_from_fd(ctx, fd, &busnum, &devaddr);
+	if (r != LIBUSB_SUCCESS)
+		return r;
 
 	/* Session id is unused as we do not add the device to the list of
 	 * connected devices. */
diff --git a/libusb/os/linux_usbfs.h b/libusb/os/linux_usbfs.h
index a57eb41..2449632 100644
--- a/libusb/os/linux_usbfs.h
+++ b/libusb/os/linux_usbfs.h
@@ -187,7 +187,7 @@ void linux_device_disconnected(uint8_t busnum, uint8_t devaddr);
 
 int linux_get_device_address (struct libusb_context *ctx, int detached,
 	uint8_t *busnum, uint8_t *devaddr, const char *dev_node,
-	const char *sys_name, int fd);
+	const char *sys_name);
 int linux_enumerate_device(struct libusb_context *ctx,
 	uint8_t busnum, uint8_t devaddr, const char *sysfs_dir);
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog