I am curious (I am still looking myself but I thought tapping into the vast knowledge-base here at LQ might help) if /proc/bus/usb/devices holds any valuable information regarding the /dev/ location of a USB device? If it doesn't hold a direct link to such information, perhaps it holds an indirect link that can be gathered from another file?

I would like to create an array list of USB block-devices by NAME from the /proc/ listing, and, with as little over-head as possible, mount a device based on the array information. For example, I would grab the name and <key> information about the device in array[1], I would then present, by name, a list of devices from the /proc/ listing and upon selection, mount the appropriate device. As I see it now, /proc/ doesn't leave me with much about the actual location of the device as much as information about the device itself.

Thanks, in advance, for any tips/help!

I suspect you won't find nothing useful in /proc/bus/usb/devices since usb block devices use usb-scsi emulation. Usb block drives/flashes use usb_storage driver that enables scsi emulation. You can find some infos about your device on /proc/scsi/usb-storage/0 (may be a different number according to the number of devices connected to the system), but not infos on where the drive is attached to. On my system I get
cat /proc/scsi/usb-storage/0
Host scsi0: usb-storage
Vendor: LEXR PLUG DRIVE
Product: LEXR PLUG DRIVE
Serial Number: 000000105071405266050000000000000000000000000
Protocol: Transparent SCSI
Transport: Bulk
Quirks:
If you want to know where you devices are attached (ie usb controller) I'd have a look to udev tools output (only 2.6 kernels) like udevinfo.
Here is a typical output for an usb pendrive

udevinfo starts with the device the node belongs to and then walks up the
device chain, to print for every device found, all possibly useful attributes
in the udev key format.
Only attributes within one device section may be used together in one rule,
to match the device for which the node will be created.

looking at device '/block/sda/sda1':
KERNEL=="sda1"
SUBSYSTEM=="block"
SYSFS{stat}==" 17 136 0 0"
SYSFS{size}=="250592"
SYSFS{start}=="32"
SYSFS{dev}=="8:1"

looking at device '/block/sda':
ID=="sda"
BUS=="block"
DRIVER==""
SYSFS{stat}==" 11 7 144 142 0 0 0 0 0 142 142"
SYSFS{size}=="251904"
SYSFS{removable}=="1"
SYSFS{range}=="16"
SYSFS{dev}=="8:0"

looking at device '/devices/pci0000:00/0000:00:03.1/usb3/3-2/3-2:1.0/host0/target0:0:0/0:0:0:0':
ID=="0:0:0:0"
BUS=="scsi"
DRIVER=="sd"
SYSFS{ioerr_cnt}=="0x1"
SYSFS{iodone_cnt}=="0x18"
SYSFS{iorequest_cnt}=="0x18"
SYSFS{iocounterbits}=="32"
SYSFS{timeout}=="30"
SYSFS{state}=="running"
SYSFS{rev}=="1.01"
SYSFS{model}=="JUMPDRIVE "
SYSFS{vendor}=="LEXAR "
SYSFS{scsi_level}=="3"
SYSFS{type}=="0"
SYSFS{queue_type}=="none"
SYSFS{queue_depth}=="1"
SYSFS{device_blocked}=="0"
SYSFS{max_sectors}=="240"

looking at device '/devices/pci0000:00/0000:00:03.1/usb3/3-2/3-2:1.0/host0/target0:0:0':
ID=="target0:0:0"
BUS==""
DRIVER==""

looking at device '/devices/pci0000:00/0000:00:03.1/usb3/3-2/3-2:1.0/host0':
ID=="host0"
BUS==""
DRIVER==""

looking at device '/devices/pci0000:00/0000:00:03.1/usb3/3-2/3-2:1.0':
ID=="3-2:1.0"
BUS=="usb"
DRIVER=="usb-storage"
SYSFS{interface}=="LEXR PLUG DRIVE"
SYSFS{modalias}=="usb:v05DCp0080d0001dc00dsc00dp00ic08isc06ip50"
SYSFS{bInterfaceProtocol}=="50"
SYSFS{bInterfaceSubClass}=="06"
SYSFS{bInterfaceClass}=="08"
SYSFS{bNumEndpoints}=="02"
SYSFS{bAlternateSetting}==" 0"
SYSFS{bInterfaceNumber}=="00"

looking at device '/devices/pci0000:00/0000:00:03.1/usb3/3-2':
ID=="3-2"
BUS=="usb"
DRIVER=="usb"
SYSFS{configuration}==""
SYSFS{serial}=="000000105071405266050000000000000000000000000"
SYSFS{product}=="LEXR PLUG DRIVE"
SYSFS{manufacturer}=="LEXR PLUG DRIVE"
SYSFS{maxchild}=="0"
SYSFS{version}==" 1.10"
SYSFS{devnum}=="2"
SYSFS{speed}=="12"
SYSFS{bMaxPacketSize0}=="8"
SYSFS{bNumConfigurations}=="1"
SYSFS{bDeviceProtocol}=="00"
SYSFS{bDeviceSubClass}=="00"
SYSFS{bDeviceClass}=="00"
SYSFS{bcdDevice}=="0001"
SYSFS{idProduct}=="0080"
SYSFS{idVendor}=="05dc"
SYSFS{bMaxPower}==" 90mA"
SYSFS{bmAttributes}=="80"
SYSFS{bConfigurationValue}=="1"
SYSFS{bNumInterfaces}==" 1"

looking at device '/devices/pci0000:00/0000:00:03.1/usb3':
ID=="usb3"
BUS=="usb"
DRIVER=="usb"
SYSFS{configuration}==""
SYSFS{serial}=="0000:00:03.1"
SYSFS{product}=="OHCI Host Controller"
SYSFS{manufacturer}=="Linux 2.6.16.9 ohci_hcd"
SYSFS{maxchild}=="3"
SYSFS{version}==" 1.10"
SYSFS{devnum}=="1"
SYSFS{speed}=="12"
SYSFS{bMaxPacketSize0}=="64"
SYSFS{bNumConfigurations}=="1"
SYSFS{bDeviceProtocol}=="00"
SYSFS{bDeviceSubClass}=="00"
SYSFS{bDeviceClass}=="09"
SYSFS{bcdDevice}=="0206"
SYSFS{idProduct}=="0000"
SYSFS{idVendor}=="0000"
SYSFS{bMaxPower}==" 0mA"
SYSFS{bmAttributes}=="c0"
SYSFS{bConfigurationValue}=="1"
SYSFS{bNumInterfaces}==" 1"

looking at device '/devices/pci0000:00/0000:00:03.1':
ID=="0000:00:03.1"
BUS=="pci"
DRIVER=="ohci_hcd"
SYSFS{modalias}=="pci:v00001039d00007001sv00001043sd0000810Ebc0Csc03i10"
SYSFS{local_cpus}=="1"
SYSFS{irq}=="21"
SYSFS{class}=="0x0c0310"
SYSFS{subsystem_device}=="0x810e"
SYSFS{subsystem_vendor}=="0x1043"
SYSFS{device}=="0x7001"
SYSFS{vendor}=="0x1039"

looking at device '/devices/pci0000:00':
ID=="pci0000:00"
BUS==""
DRIVER==""

No idea how to use such infos for your purpose (let me say it is rather unusual)
Hope this helps
Ciao

That is, indeed, useful information.

I want to make the interface more natural for a piece of software that mounts devices (it is my introductory project into C); it doesn't seem intuitive to mount a device based on device locations, so I'd like to give actual device names. Just a little problem I find interesting. There is probably a better way but I sure don't know about it


Thanks for the great info, I will pursue it and see where it takes me.

*EDIT* It doesn't mount them as its whole purpose, it will simply mount a device if it needs *EDIT*

*EDIT2* With your guidance above, I found my way to The Linux SCSI Generic (sg) HOWTO, which will work on both 2.4 and 2.6 kernels. It provides me with the means to derive device information via the /dev/location I will post back with the final version (C code, probably) of the code that makes the connection between the device as mapped on the system and the actual device information (name, manufacturer, etc). I am most appreciative of your post and guidance. *EDIT2.

I'd be glad to see your work posted when finished.
I'm very curious ....
Ciao

Huge Edit!

I proposed a terribly inefficient (and ultimately impossible) method to determine where a device is located and its name....however, it is much more simple.

The SCSI interface provides all the necessary information. I'm sorry I don't have an update, this seems like a spam post but I don't believe LQ has a way of deleting your messages.

Given the nature of my program, it will sometimes be confusing linking the SCSI subsystem information with the USB device information as many USB devices are made with purchased hardware (such as an MP3 player being made by company X with company Y's hard-drive inside, in this case, the SCSI inquiry will return the hard-drive device information, whereas, the USB device will return the expected information).