[Qemu-devel] [PATCH] Add USB sys file-system support (v2)

[TJ <linux@tjworld.net>]

Revision 2.

I realised I'd made a major programming boo-boo despite knowing better -
requesting an allocation of memory in the host USB file-system scan
function, forgetting that the function isn't just called once but
repeatedly. That would have led to orphaned memory allocations each time
a USB scan or open operation occurred - baaad!

I've also changed the logic so it only scans for the USB file-system
type the first time. After that it works off stored values.

=======
This patch adds support for host USB devices discovered via:

/sys/bus/usb/devices/* and opened from /dev/bus/usb/*/*
/dev/bus/usb/devices and opened from /dev/bus/usb/*/*

in addition to the existing discovery via:

/proc/bus/usb/devices and opened from /proc/bus/usb/*/*

Signed-off-by: TJ <linux@tjworld.net>
---
 qemu/usb-linux.c |  367 +++++++++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 292 insertions(+), 75 deletions(-)

diff --git a/qemu/usb-linux.c b/qemu/usb-linux.c
index 8ee789f..40fce47 100644
--- a/qemu/usb-linux.c
+++ b/qemu/usb-linux.c
@@ -7,6 +7,10 @@
  *      Support for host device auto connect & disconnect
  *      Magor rewrite to support fully async operation
  *
+ * Copyright 2008 TJ <linux@tjworld.net>
+ *      Added flexible support for /dev/bus/usb /sys/bus/usb/devices in addition
+ *      to the legacy /proc/bus/usb USB device discovery and handling
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
@@ -65,9 +69,20 @@ static int usb_host_find_device(int *pbus_num, int *paddr,
 #define dprintf(...)
 #endif
 
-#define USBDEVFS_PATH "/proc/bus/usb"
+#define USBPROCBUS_PATH "/proc/bus/usb"
 #define PRODUCT_NAME_SZ 32
 #define MAX_ENDPOINTS 16
+#define USBDEVBUS_PATH "/dev/bus/usb"
+#define USBSYSBUS_PATH "/sys/bus/usb"
+
+static char *USBHostDevicePath = 0;
+
+#define USB_FS_NONE 0
+#define USB_FS_PROC 1
+#define USB_FS_DEV 2
+#define USB_FS_SYS 3
+
+static int USBfs = 0;
 
 struct sigaction sigact;
 
@@ -600,13 +615,18 @@ static USBDevice *usb_host_device_open_addr(int bus_num, int addr, const char *p
 
     printf("husb: open device %d.%d\n", bus_num, addr);
 
-    snprintf(buf, sizeof(buf), USBDEVFS_PATH "/%03d/%03d",
+	if (!USBHostDevicePath) {
+		perror("husb: USB Host Device Path not set");
+		goto fail;
+	}
+    snprintf(buf, sizeof(buf), "%s/%03d/%03d", USBHostDevicePath,
              bus_num, addr);
     fd = open(buf, O_RDWR | O_NONBLOCK);
     if (fd < 0) {
         perror(buf);
         goto fail;
     }
+    printf("husb: opened %s\n", buf);
 
     /* read the device description */
     dev->descr_len = read(fd, dev->descr, sizeof(dev->descr));
@@ -629,9 +649,10 @@ static USBDevice *usb_host_device_open_addr(int bus_num, int addr, const char *p
     dev->configuration = 1;
 
     /* XXX - do something about initial configuration */
-    if (!usb_host_update_interfaces(dev, -1))
+    if (!usb_host_update_interfaces(dev, -1)) {
+        perror("usb_host_device_open: update interfaces");
         goto fail;
-
+    }
     ret = ioctl(fd, USBDEVFS_CONNECTINFO, &ci);
     if (ret < 0) {
         perror("usb_host_device_open: USBDEVFS_CONNECTINFO");
@@ -717,81 +738,277 @@ static int get_tag_value(char *buf, int buf_size,
     return q - buf;
 }
 
+/*
+ Use /proc/bus/usb/devices or /dev/bus/usb/devices file to determine
+ host's USB devices. This is legacy support since many distributions
+ are moving to /sys/bus/usb
+*/
+static int usb_host_scan_dev(void *opaque, USBScanFunc *func)
+{
+	FILE *f = 0;
+	char line[1024];
+	char buf[1024];
+	int bus_num, addr, speed, device_count, class_id, product_id, vendor_id;
+	char product_name[512];
+	int ret = 0;
+
+	snprintf(line, sizeof(line), "%s/devices", USBHostDevicePath);
+	f = fopen(line, "r");
+	if (!f) {
+		perror("husb: cannot open devices file");
+		goto the_end;
+	}
+
+	device_count = 0;
+	bus_num = addr = speed = class_id = product_id = vendor_id = 0;
+	for(;;) {
+		if (fgets(line, sizeof(line), f) == NULL)
+			break;
+		if (strlen(line) > 0)
+			line[strlen(line) - 1] = '\0';
+		if (line[0] == 'T' && line[1] == ':') {
+			if (device_count && (vendor_id || product_id)) {
+				/* New device.  Add the previously discovered device.  */
+				ret = func(opaque, bus_num, addr, class_id, vendor_id,
+							product_id, product_name, speed);
+				if (ret)
+					goto the_end;
+			}
+			if (get_tag_value(buf, sizeof(buf), line, "Bus=", " ") < 0)
+				goto fail;
+
+			bus_num = atoi(buf);
+			if (get_tag_value(buf, sizeof(buf), line, "Dev#=", " ") < 0)
+				goto fail;
+
+			addr = atoi(buf);
+			if (get_tag_value(buf, sizeof(buf), line, "Spd=", " ") < 0)
+				goto fail;
+
+			if (!strcmp(buf, "480"))
+				speed = USB_SPEED_HIGH;
+			else if (!strcmp(buf, "1.5"))
+				speed = USB_SPEED_LOW;
+			else
+				speed = USB_SPEED_FULL;
+			product_name[0] = '\0';
+			class_id = 0xff;
+			device_count++;
+			product_id = 0;
+			vendor_id = 0;
+		}
+		else if (line[0] == 'P' && line[1] == ':') {
+			if (get_tag_value(buf, sizeof(buf), line, "Vendor=", " ") < 0)
+				goto fail;
+
+			vendor_id = strtoul(buf, NULL, 16);
+			if (get_tag_value(buf, sizeof(buf), line, "ProdID=", " ") < 0)
+				goto fail;
+
+			product_id = strtoul(buf, NULL, 16);
+		}
+		else if (line[0] == 'S' && line[1] == ':') {
+			if (get_tag_value(buf, sizeof(buf), line, "Product=", "") < 0)
+				goto fail;
+
+			pstrcpy(product_name, sizeof(product_name), buf);
+		}
+		else if (line[0] == 'D' && line[1] == ':') {
+			if (get_tag_value(buf, sizeof(buf), line, "Cls=", " (") < 0)
+				goto fail;
+
+			class_id = strtoul(buf, NULL, 16);
+		}
+ fail: ;
+	}
+	if (device_count && (vendor_id || product_id)) {
+		/* Add the last device.  */
+		ret = func(opaque, bus_num, addr, class_id, vendor_id,
+					product_id, product_name, speed);
+	}
+ the_end:
+	if (f) fclose(f);
+	return ret;
+}
+
+/*
+ Use /sys/bus/usb/devices/ directory to determine host's USB devices.
+
+ This code is taken from Robert Schiele's original patches posted to the
+ Novell bug-tracker https://bugzilla.novell.com/show_bug.cgi?id=241950
+*/
+static int usb_host_scan_sys(void *opaque, USBScanFunc *func)
+{
+	FILE *f;
+	DIR *dir = 0;
+	char line[1024];
+	int bus_num, addr, speed, class_id, product_id, vendor_id;
+	int ret = 0;
+	char product_name[512];
+	struct dirent* de;
+
+	dir = opendir(USBSYSBUS_PATH "/devices");
+	if (!dir) {
+		perror("husb: cannot open devices directory");
+		goto the_end;
+	}
+
+	while ((de = readdir(dir))) {
+		if (de->d_name[0] != '.' && ! strchr(de->d_name, ':')) {
+			char filename[PATH_MAX];
+			char* tmpstr = de->d_name;
+			if (!strncmp(de->d_name, "usb", 3))
+				tmpstr += 3;
+
+			bus_num = atoi(tmpstr);
+			snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/devnum", de->d_name);
+			f = fopen(filename, "r");
+			if (!f) {
+				term_printf("Could not open %s\n", filename);
+				goto the_end;
+			}
+			fgets(line, sizeof(line), f);
+			fclose(f);
+			addr = atoi(line);
+			snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/bDeviceClass", de->d_name);
+			f = fopen(filename, "r");
+			if (!f) {
+				term_printf("Could not open %s\n", filename);
+				goto the_end;
+			}
+			fgets(line, sizeof(line), f);
+			fclose(f);
+			class_id = strtoul(line, NULL, 16);
+			snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/idVendor", de->d_name);
+			f = fopen(filename, "r");
+			if (!f) {
+				term_printf("Could not open %s\n", filename);
+				goto the_end;
+			}
+			fgets(line, sizeof(line), f);
+			fclose(f);
+			vendor_id = strtoul(line, NULL, 16);
+			snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/idProduct", de->d_name);
+			f = fopen(filename, "r");
+			if (!f) {
+				term_printf("Could not open %s\n", filename);
+				goto the_end;
+			}
+			fgets(line, sizeof(line), f);
+			fclose(f);
+			product_id = strtoul(line, NULL, 16);
+			snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/product", de->d_name);
+			f = fopen(filename, "r");
+			if (f) {
+				fgets(line, sizeof(line), f);
+				fclose(f);
+				if (strlen(line) > 0)
+					line[strlen(line) - 1] = '\0';
+
+				pstrcpy(product_name, sizeof(product_name), line);
+			} else
+				*product_name = 0;
+
+			snprintf(filename, PATH_MAX, USBSYSBUS_PATH "/devices/%s/speed", de->d_name);
+			f = fopen(filename, "r");
+			if (!f) {
+				term_printf("Could not open %s\n", filename);
+				goto the_end;
+			}
+			fgets(line, sizeof(line), f);
+			fclose(f);
+			if (!strcmp(line, "480\n"))
+				speed = USB_SPEED_HIGH;
+			else if (!strcmp(line, "1.5\n"))
+				speed = USB_SPEED_LOW;
+			else
+				speed = USB_SPEED_FULL;
+
+			ret = func(opaque, bus_num, addr, class_id, vendor_id,
+						product_id, product_name, speed);
+		}
+	}
+ the_end:
+	if (dir) closedir(dir);
+	return ret;
+}
+
+/*
+ Determine how to access the host's USB devices and call the specific
+ support function.
+
+ Introduced to fix Ubuntu LP #156085
+ https://bugs.launchpad.net/ubuntu/+bug/156085
+ */
 static int usb_host_scan(void *opaque, USBScanFunc *func)
 {
-    FILE *f;
-    char line[1024];
-    char buf[1024];
-    int bus_num, addr, speed, device_count, class_id, product_id, vendor_id;
-    int ret;
-    char product_name[512];
+	FILE *f = 0;
+	DIR *dir = 0;
+	int ret = 0;
+	char *devices = "/devices";
+	char *trying = "husb: trying to open %s%s\n";
+	char *failed = "husb: could not open %s%s\n";
+	char devpath[PATH_MAX];
+
+	// only check the host once
+	if (!USBfs) {
+		// test for dev file-system access in /proc/
+		term_printf(trying, USBPROCBUS_PATH, devices);
+		f = fopen(USBPROCBUS_PATH "/devices", "r");
+		if (!f) {
+			term_printf(failed, USBPROCBUS_PATH, devices);
+			// maybe it has been moved to the /dev/ base
+			term_printf(trying, USBDEVBUS_PATH, devices);
+			f = fopen(USBDEVBUS_PATH "/devices", "r");
+			if (!f) {
+				term_printf(failed, USBDEVBUS_PATH, devices);
+				// test for newer sys file-system access
+				term_printf(trying, USBSYSBUS_PATH, devices);
+				dir = opendir(USBSYSBUS_PATH "/devices");
+				if (!dir) {
+					term_printf(failed, USBSYSBUS_PATH, devices);
+					goto the_end;
+				}
+				else { // devices found in /dev/bus/usb/ (yes - not a mistake!)
+					strcpy(devpath, USBDEVBUS_PATH);
+					USBfs = USB_FS_SYS;
+				}
+				if (dir) closedir(dir);
+			}
+			else { // devices found in /dev/bus/usb/
+				strcpy(devpath, USBDEVBUS_PATH);
+				USBfs = USB_FS_DEV;
+			}
+		}
+		else { // devices found in /proc/bus/usb/
+			strcpy(devpath, USBPROCBUS_PATH);
+			USBfs = USB_FS_PROC;
+		}
+		if (f) fclose(f);
+
+		// the module setting (used later for opening devices)
+		USBHostDevicePath = qemu_mallocz(strlen(devpath)+1);
+		if (USBHostDevicePath) {
+			strcpy(USBHostDevicePath, devpath);
+			term_printf("husb: using %s\n", USBHostDevicePath);
+		}
+		else { // out of memory?
+			perror("husb: unable to allocate memory for device path");
+			goto the_end;
+		}
+	}
 
-    f = fopen(USBDEVFS_PATH "/devices", "r");
-    if (!f) {
-        term_printf("husb: could not open %s\n", USBDEVFS_PATH "/devices");
-        return 0;
-    }
-    device_count = 0;
-    bus_num = addr = speed = class_id = product_id = vendor_id = 0;
-    ret = 0;
-    for(;;) {
-        if (fgets(line, sizeof(line), f) == NULL)
-            break;
-        if (strlen(line) > 0)
-            line[strlen(line) - 1] = '\0';
-        if (line[0] == 'T' && line[1] == ':') {
-            if (device_count && (vendor_id || product_id)) {
-                /* New device.  Add the previously discovered device.  */
-                ret = func(opaque, bus_num, addr, class_id, vendor_id,
-                           product_id, product_name, speed);
-                if (ret)
-                    goto the_end;
-            }
-            if (get_tag_value(buf, sizeof(buf), line, "Bus=", " ") < 0)
-                goto fail;
-            bus_num = atoi(buf);
-            if (get_tag_value(buf, sizeof(buf), line, "Dev#=", " ") < 0)
-                goto fail;
-            addr = atoi(buf);
-            if (get_tag_value(buf, sizeof(buf), line, "Spd=", " ") < 0)
-                goto fail;
-            if (!strcmp(buf, "480"))
-                speed = USB_SPEED_HIGH;
-            else if (!strcmp(buf, "1.5"))
-                speed = USB_SPEED_LOW;
-            else
-                speed = USB_SPEED_FULL;
-            product_name[0] = '\0';
-            class_id = 0xff;
-            device_count++;
-            product_id = 0;
-            vendor_id = 0;
-        } else if (line[0] == 'P' && line[1] == ':') {
-            if (get_tag_value(buf, sizeof(buf), line, "Vendor=", " ") < 0)
-                goto fail;
-            vendor_id = strtoul(buf, NULL, 16);
-            if (get_tag_value(buf, sizeof(buf), line, "ProdID=", " ") < 0)
-                goto fail;
-            product_id = strtoul(buf, NULL, 16);
-        } else if (line[0] == 'S' && line[1] == ':') {
-            if (get_tag_value(buf, sizeof(buf), line, "Product=", "") < 0)
-                goto fail;
-            pstrcpy(product_name, sizeof(product_name), buf);
-        } else if (line[0] == 'D' && line[1] == ':') {
-            if (get_tag_value(buf, sizeof(buf), line, "Cls=", " (") < 0)
-                goto fail;
-            class_id = strtoul(buf, NULL, 16);
-        }
-    fail: ;
-    }
-    if (device_count && (vendor_id || product_id)) {
-        /* Add the last device.  */
-        ret = func(opaque, bus_num, addr, class_id, vendor_id,
-                   product_id, product_name, speed);
-    }
+	switch (USBfs) {
+		case USB_FS_PROC:
+		case USB_FS_DEV:
+			ret = usb_host_scan_dev(opaque, func);
+			break;
+		case USB_FS_SYS:
+			ret = usb_host_scan_sys(opaque, func);
+			break;
+	}
  the_end:
-    fclose(f);
-    return ret;
+	return ret;
 }
 
 struct USBAutoFilter {
-- 
1.5.4.3