[Qemu-devel] [PATCH] Add USB sys file-system support (v6)

[TJ <linux@tjworld.net>]

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>
---
--- a/usb-linux.c	2008-09-17 22:39:38.000000000 +0100
+++ b/usb-linux.c	2008-09-23 02:28:48.000000000 +0100
@@ -7,6 +7,10 @@
  *      Support for host device auto connect & disconnect
  *      Major 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
@@ -72,9 +76,20 @@
 #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 *usb_host_device_path;
+
+#define USB_FS_NONE 0
+#define USB_FS_PROC 1
+#define USB_FS_DEV 2
+#define USB_FS_SYS 3
+
+static int usb_fs_type = 0;
 
 /* endpoint association data */
 struct endp_data {
@@ -890,13 +905,18 @@
 
     printf("husb: open device %d.%d\n", bus_num, addr);
 
-    snprintf(buf, sizeof(buf), USBDEVFS_PATH "/%03d/%03d",
+	if (!usb_host_device_path) {
+		perror("husb: USB Host Device Path not set");
+		goto fail;
+	}
+    snprintf(buf, sizeof(buf), "%s/%03d/%03d", usb_host_device_path,
              bus_num, addr);
     fd = open(buf, O_RDWR | O_NONBLOCK);
     if (fd < 0) {
         perror(buf);
         goto fail;
     }
+    dprintf("husb: opened %s\n", buf);
 
     /* read the device description */
     dev->descr_len = read(fd, dev->descr, sizeof(dev->descr));
@@ -1038,23 +1058,29 @@
     return q - buf;
 }
 
-static int usb_host_scan(void *opaque, USBScanFunc *func)
+/*
+ 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;
+    FILE *f = 0;
     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];
+    int ret = 0;
 
-    f = fopen(USBDEVFS_PATH "/devices", "r");
+    snprintf(line, sizeof(line), "%s/devices", usb_host_device_path);
+    f = fopen(line, "r");
     if (!f) {
-        term_printf("husb: could not open %s\n", USBDEVFS_PATH "/devices");
-        return 0;
+    	perror("husb: cannot open devices file");
+    	goto the_end;
     }
+
     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;
@@ -1106,12 +1132,191 @@
     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);
+    	/* 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);
+    		if (ret)
+    			goto the_end;
+    	}
+    }
+ the_end:
+    if (dir) closedir(dir);
+    return ret;
+}
+
+/*
+ Determine how to access the host's USB devices and call the specific
+ support function.
+ */
+static int usb_host_scan(void *opaque, USBScanFunc *func)
+{
+    FILE *f = 0;
+    DIR *dir = 0;
+    int ret = 0;
+    const char *devices = "/devices";
+    const char *trying = "husb: trying to open %s%s\n";
+    const char *failed = "husb: could not open %s%s\n";
+    char devpath[PATH_MAX];
+
+    // only check the host once
+    if (!usb_fs_type) {
+    	// test for dev file-system access in /proc/
+    	dprintf(trying, USBPROCBUS_PATH, devices);
+    	f = fopen(USBPROCBUS_PATH "/devices", "r");
+    	if (!f) {
+    		dprintf(failed, USBPROCBUS_PATH, devices);
+    		// maybe it has been moved to the /dev/ base
+    		dprintf(trying, USBDEVBUS_PATH, devices);
+    		f = fopen(USBDEVBUS_PATH "/devices", "r");
+    		if (!f) {
+    			dprintf(failed, USBDEVBUS_PATH, devices);
+    			// test for newer sys file-system access
+    			dprintf(trying, USBSYSBUS_PATH, devices);
+    			dir = opendir(USBSYSBUS_PATH "/devices");
+    			if (!dir) {
+    				dprintf(failed, USBSYSBUS_PATH, devices);
+    				goto the_end;
+    			}
+    			else { // devices found in /dev/bus/usb/ (yes - not a mistake!)
+    				strcpy(devpath, USBDEVBUS_PATH);
+    				usb_fs_type = USB_FS_SYS;
+    			}
+    			if (dir) closedir(dir);
+    		}
+    		else { // devices found in /dev/bus/usb/
+    			strcpy(devpath, USBDEVBUS_PATH);
+    			usb_fs_type = USB_FS_DEV;
+    		}
+    	}
+    	else { // devices found in /proc/bus/usb/
+    		strcpy(devpath, USBPROCBUS_PATH);
+    		usb_fs_type = USB_FS_PROC;
+    	}
+    	if (f) fclose(f);
+
+    	// the module setting (used later for opening devices)
+    	usb_host_device_path = qemu_mallocz(strlen(devpath)+1);
+    	if (usb_host_device_path) {
+    		strcpy(usb_host_device_path, devpath);
+    		term_printf("husb: using %s\n", usb_host_device_path);
+    	}
+    	else { // out of memory?
+    		perror("husb: unable to allocate memory for device path");
+    		goto the_end;
+    	}
+    }
+
+    switch (usb_fs_type) {
+    	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;
 }