From 8418bf71b08124ded641909a7056cafe4ecbf557 Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dtor@chromium.org>
Date: Tue, 4 Jun 2019 23:37:31 -0700
Subject: [PATCH 07/11] CHROMIUM: linux_usbfs: split initialize_device()

In preparation to using the new USBFS_CONNINFO_EX ioctl allowing fetch
more data from usbfs, let's split apart initialize_device() to make the
logic clearer.

Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
---
 libusb/os/linux_usbfs.c | 185 ++++++++++++++++++++++++----------------
 1 file changed, 113 insertions(+), 72 deletions(-)

diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
index b55b86d..0ba38c3 100644
--- a/libusb/os/linux_usbfs.c
+++ b/libusb/os/linux_usbfs.c
@@ -999,98 +999,74 @@ static int usbfs_get_active_config(struct libusb_device *dev, int fd)
 	return LIBUSB_SUCCESS;
 }
 
-static int initialize_device(struct libusb_device *dev, uint8_t busnum,
-	uint8_t devaddr, const char *sysfs_dir, int wrapped_fd)
+static int device_cache_descriptors(struct libusb_context *ctx,
+	struct linux_device_priv *priv, int fd)
 {
-	struct linux_device_priv *priv = _device_priv(dev);
-	struct libusb_context *ctx = DEVICE_CTX(dev);
 	int descriptors_size = 512; /* Begin with a 1024 byte alloc */
-	int fd, speed;
 	ssize_t r;
 
-	dev->bus_number = busnum;
-	dev->device_address = devaddr;
-
-	if (sysfs_dir) {
-		priv->sysfs_dir = strdup(sysfs_dir);
-		if (!priv->sysfs_dir)
-			return LIBUSB_ERROR_NO_MEM;
-
-		/* Note speed can contain 1.5, in this case __read_sysfs_attr
-		   will stop parsing at the '.' and return 1 */
-		speed = __read_sysfs_attr(DEVICE_CTX(dev), sysfs_dir, "speed");
-		if (speed >= 0) {
-			switch (speed) {
-			case     1: dev->speed = LIBUSB_SPEED_LOW; break;
-			case    12: dev->speed = LIBUSB_SPEED_FULL; break;
-			case   480: dev->speed = LIBUSB_SPEED_HIGH; break;
-			case  5000: dev->speed = LIBUSB_SPEED_SUPER; break;
-			case 10000: dev->speed = LIBUSB_SPEED_SUPER_PLUS; break;
-			default:
-				usbi_warn(DEVICE_CTX(dev), "Unknown device speed: %d Mbps", speed);
-			}
-		}
-	}
-
-	/* cache descriptors in memory */
-	if (sysfs_dir && sysfs_has_descriptors) {
-		fd = _open_sysfs_attr(dev, "descriptors");
-	} else if (wrapped_fd < 0) {
-		fd = _get_usbfs_fd(dev, O_RDONLY, 0);
-	} else {
-		fd = wrapped_fd;
-		r = lseek(fd, 0, SEEK_SET);
-		if (r < 0) {
-			usbi_err(ctx, "seek failed ret=%d errno=%d", r, errno);
-			return LIBUSB_ERROR_IO;
-		}
-	}
-	if (fd < 0)
-		return fd;
-
 	do {
 		descriptors_size *= 2;
 		priv->descriptors = usbi_reallocf(priv->descriptors,
 						  descriptors_size);
-		if (!priv->descriptors) {
-			if (fd != wrapped_fd)
-				close(fd);
+		if (!priv->descriptors)
 			return LIBUSB_ERROR_NO_MEM;
-		}
-		/* usbfs has holes in the file */
-		if (!(sysfs_dir && sysfs_has_descriptors)) {
-			memset(priv->descriptors + priv->descriptors_len,
-			       0, descriptors_size - priv->descriptors_len);
-		}
+
+		/* usbfs has holes in the file so let's clear the buffer
+		 * before passing it to the kernel. */
+		memset(priv->descriptors + priv->descriptors_len,
+		       0, descriptors_size - priv->descriptors_len);
+
 		r = read(fd, priv->descriptors + priv->descriptors_len,
 			 descriptors_size - priv->descriptors_len);
 		if (r < 0) {
 			usbi_err(ctx, "read descriptor failed ret=%d errno=%d",
 				 fd, errno);
-			if (fd != wrapped_fd)
-				close(fd);
 			return LIBUSB_ERROR_IO;
 		}
 		priv->descriptors_len += r;
 	} while (priv->descriptors_len == descriptors_size);
 
-	if (fd != wrapped_fd)
-		close(fd);
-
 	if (priv->descriptors_len < DEVICE_DESC_LENGTH) {
 		usbi_err(ctx, "short descriptor read (%d)",
 			 priv->descriptors_len);
 		return LIBUSB_ERROR_IO;
 	}
 
-	if (sysfs_dir && sysfs_can_relate_devices)
-		return LIBUSB_SUCCESS;
+	return LIBUSB_SUCCESS;
+}
 
-	/* cache active config */
-	if (wrapped_fd < 0)
-		fd = _get_usbfs_fd(dev, O_RDWR, 1);
-	else
-		fd = wrapped_fd;
+static int device_speed_from_sysfs(struct libusb_context *ctx,
+	const char *sysfs_dir)
+{
+	int speed;
+
+	/* Note speed can contain 1.5, in this case __read_sysfs_attr
+	   will stop parsing at the '.' and return 1 */
+	speed = __read_sysfs_attr(ctx, sysfs_dir, "speed");
+	if (speed < 0)
+		return LIBUSB_SPEED_UNKNOWN;
+
+	switch (speed) {
+	case     1: return LIBUSB_SPEED_LOW;
+	case    12: return LIBUSB_SPEED_FULL;
+	case   480: return LIBUSB_SPEED_HIGH;
+	case  5000: return LIBUSB_SPEED_SUPER;
+	case 10000: return LIBUSB_SPEED_SUPER_PLUS;
+	default:
+		usbi_warn(ctx, "Unknown device speed: %d Mbps", speed);
+		return LIBUSB_SPEED_UNKNOWN;
+	}
+}
+
+static int device_cache_active_config(struct libusb_device *dev, int wrapped_fd)
+{
+	struct linux_device_priv *priv = _device_priv(dev);
+	struct libusb_context *ctx = DEVICE_CTX(dev);
+	int fd;
+	int ret;
+
+	fd = wrapped_fd >= 0 ? dup(wrapped_fd) : _get_usbfs_fd(dev, O_RDWR, 1);
 	if (fd < 0) {
 		/* cannot send a control message to determine the active
 		 * config. just assume the first one is active. */
@@ -1103,17 +1079,82 @@ static int initialize_device(struct libusb_device *dev, uint8_t busnum,
 				priv->descriptors + DEVICE_DESC_LENGTH,
 				"bbwbbbbb", &config, 0);
 			priv->active_config = config.bConfigurationValue;
-		} else
+		} else {
 			priv->active_config = -1; /* No config dt */
-
+		}
 		return LIBUSB_SUCCESS;
 	}
 
-	r = usbfs_get_active_config(dev, fd);
-	if (wrapped_fd < 0)
-		close(fd);
+	ret = usbfs_get_active_config(dev, fd);
+	close(fd);
+	return ret;
+}
 
-	return r;
+static int initialize_from_usbfs(struct libusb_device *dev, int fd)
+{
+	struct linux_device_priv *priv = _device_priv(dev);
+	struct libusb_context *ctx = DEVICE_CTX(dev);
+	int ret;
+
+	ret = lseek(fd, 0, SEEK_SET);
+	if (ret < 0) {
+		usbi_err(ctx, "seek failed ret=%d errno=%d", ret, errno);
+		return LIBUSB_ERROR_IO;
+	}
+
+	return device_cache_descriptors(ctx, priv, fd);
+}
+
+static int initialize_device(struct libusb_device *dev, uint8_t busnum,
+	uint8_t devaddr, const char *sysfs_dir, int wrapped_fd)
+{
+	struct linux_device_priv *priv = _device_priv(dev);
+	struct libusb_context *ctx = DEVICE_CTX(dev);
+	int sysfs_fd, usbfs_fd;
+	int ret;
+
+	/* Seed the device address. We might need to adjust them if
+	 * we have file descriptor. */
+	dev->bus_number = busnum;
+	dev->device_address = devaddr;
+
+	/* If we have sysfs access we can get most of the data from it
+	 * even if we do not have valid file descriptor. */
+	if (sysfs_dir) {
+		priv->sysfs_dir = strdup(sysfs_dir);
+		if (!priv->sysfs_dir)
+			return LIBUSB_ERROR_NO_MEM;
+
+		dev->speed = device_speed_from_sysfs(ctx, sysfs_dir);
+
+		if (sysfs_has_descriptors) {
+			sysfs_fd = _open_sysfs_attr(dev, "descriptors");
+			if (sysfs_fd < 0)
+				return sysfs_fd;
+			ret = device_cache_descriptors(ctx, priv, sysfs_fd);
+			close(sysfs_fd);
+			if (ret != LIBUSB_SUCCESS)
+				return ret;
+		}
+	}
+
+	if (!priv->descriptors) {
+		usbfs_fd = wrapped_fd >= 0 ?
+				dup(wrapped_fd) :
+				_get_usbfs_fd(dev, O_RDONLY, 0 /* silent */);
+		if (usbfs_fd < 0)
+			return usbfs_fd;
+
+		ret = initialize_from_usbfs(dev, usbfs_fd);
+		close(usbfs_fd);
+		if (ret != LIBUSB_SUCCESS)
+			return ret;
+	}
+
+	if (sysfs_dir && sysfs_can_relate_devices)
+		return LIBUSB_SUCCESS;
+
+	return device_cache_active_config(dev, wrapped_fd);
 }
 
 static int linux_get_parent_info(struct libusb_device *dev, const char *sysfs_dir)
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog