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To: Paul Jackson <pj@sgi.com>
Cc: greg@kroah.com, linux-kernel@vger.kernel.org
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From: Roland Dreier <roland@topspin.com>
Date: Tue, 28 Sep 2004 08:29:39 -0700
In-Reply-To: <20040927234333.7cceff47.pj@sgi.com> (Paul Jackson's message of
 "Mon, 27 Sep 2004 23:43:33 -0700")
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Subject: Re: [PATCH][1/2] [RESEND] kobject: add HOTPLUG_ENV_VAR
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Your patch is buggy:

+	length += snprintf (buffer + length, max(buffer_size - length, 0),
 			    "DEVICE=/proc/bus/usb/%03d/%03d",
 			    usb_dev->bus->busnum, usb_dev->devnum);

snprintf() returns the number of characters that would be written not
counting the trailing NUL.  So the next env var is going to be
concatenated with this one.

It's precisely this sort of easy-to-make off-by-one bug that convinces
me the hotplug environment variable handling needs to be wrapped up in
a helper macro or function.

Thanks,
  Roland
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