Excess spaces in sysfs files

[Daniel Drake <dan@reactivated.net>]

Hi,

I have met a minor issue when writing udev rules.

Some text-like files in /sys have a load of spaces appended onto the text.

Example below, part of the udevinfo for my camera (notice the model field):

follow the class device's "device"
   looking at the device chain at 
'/sys/devices/pci0000:00/0000:00:02.1/usb3/3-3/3-3:1.0/host0/0:0:0:0':
     BUS="scsi"
     ID="0:0:0:0"
     SYSFS{detach_state}="0"
     SYSFS{max_sectors}="240"
     SYSFS{device_blocked}="0"
     SYSFS{queue_depth}="1"
     SYSFS{type}="0"
     SYSFS{scsi_level}="3"
     SYSFS{vendor}="        "
     SYSFS{model}="USB 2.0M DSC    "
     SYSFS{rev}="1.00"
     SYSFS{online}="1"

Second example, an iPod:
http://marc.theaimsgroup.com/?l=gentoo-user&m\x107773927301652&w=2

Of course, udevinfo makes it nice and clear that the extra spaces are there. 
But if you are simply cat'ing the files in /sys its not that obvious.

My questions:

1. Should these spaces be here? Are devices really identifying themselves with 
spaces on the end? Or is this an issue with sysfs/similar.

2. Should udev trim whitespace from the end of SYSFS{..} values (files), so 
that keys such as
   SYSFS{model} = "iPod"
would match a file containing
   "iPod            "

If the above behaviour is implemented, I would suggest having a second key 
type, SYSFS_RAW{..} where whitespace is not trimmed. I am prepared to write a 
patch for this.

Daniel.


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