From 00dbf19c38b3286b848ac885ea28e5233ce692ba Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 17 Feb 2012 15:30:58 -0800 Subject: Add documentation for makedev Signed-off-by: Maxime Ripard Signed-off-by: Peter Korsgaard --- docs/manual/makedev-syntax.txt | 54 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 docs/manual/makedev-syntax.txt (limited to 'docs/manual/makedev-syntax.txt') diff --git a/docs/manual/makedev-syntax.txt b/docs/manual/makedev-syntax.txt new file mode 100644 index 000000000..4728c4beb --- /dev/null +++ b/docs/manual/makedev-syntax.txt @@ -0,0 +1,54 @@ +[[makedev-syntax]] +Makedev syntax documentation +---------------------------- + +The makedev syntax is used across several places in Buildroot to +define changes to be made for permissions or which device files to +create and how to create them, in order to avoid to call mkdnod every +now and then. + +This syntax is derived from the makedev utility, and a more complete +documentation can be found in the +package/makedevs/README+ file. + +It takes the form of a line for each file, with the following layout: + +|=========================================================== +|name |type |mode |uid |gid |major |minor |start |inc |count +|=========================================================== + +There is a few non-trivial blocks here: + +- +name+ is the path to the file you want to create/modify +- +type+ is the type of the file, being one of : + * f: a regular file + * d: a directory + * c: a character device file + * b: a block device file + * p: a named pipe +- +mode+, +uid+ and +gid+ are the usual permissions stuff +- +major+ and +minor+ are here for device files +- +start+, +inc+ and +count+ are when you want to create a whole batch + of files, and can be reduced to a loop, beginning at +start+, + incrementing its counter by +inc+ until it reaches +count+ + +Let's say you want to change the permissions of a given file, using +this syntax, you will need to put: +------------------------------------------------------------------- +/usr/bin/foobar f 644 0 0 - - - - - +------------------------------------------------------------------- + +On the other hand, if you want to create the device file +/dev/hda+ +and the corresponding 15 files for the partitions, you will need for ++/dev/hda+: + +------------------------------------------------------------------- +/dev/hda b 640 0 0 3 0 0 0 - +------------------------------------------------------------------- + +and then for device files corresponding to the partitions of ++/dev/hda+, +/dev/hdaX+, +X+ ranging from 1 to 15: + +------------------------------------------------------------------- +/dev/hda b 640 0 0 3 1 1 1 15 +------------------------------------------------------------------- + -- cgit v1.2.3