[PATCH] compatibility symlinks for udev

On Mon, 2004-09-06 at 17:45 +0200, Kay Sievers wrote:
> On Mon, 2004-09-06 at 16:46 +0200, David Zeuthen wrote:
>
> Nice, I like it. It's a easy way to group device nodes of the same type,
> but coming from different kernel subsystems.
>

That's a good way of putting it, yeah.

> > Here's a patch against udev-030 that can help create compatibility
> > symlinks like /dev/cdrom, /dev/cdrom1 etc. The patch introduces a new
> > substitution type %C (for Compatibility) that can be used as follows
>
> I suggest using %e for enumeration here, cause "compatibility" can
> easily be misunderstood.
>

Good point, I've changed that.

> And we need a few lines added to the man page at udev.8.in :)
>

Done. I've also added an example.

Also, Kay pointed out offlist that the rules can be written to not
require a shell script; this actually works

        KERNEL="sr*", NAME="%k", SYMLINK="cdrom%e"
        KERNEL="scd*", NAME="%k", SYMLINK="cdrom%e"
        KERNEL="pcd*", NAME="%k", SYMLINK="cdrom%e"
        KERNEL="hd[a-z]", PROGRAM="/bin/cat /proc/ide/%k/media", RESULT="cdrom", NAME="\%k", SYMLINK="cdrom%e"
        KERNEL="fd[0-9]", NAME="%k", SYMLINK="floppy%e"
        KERNEL="hd[a-z]", PROGRAM="/bin/cat /proc/ide/%k/media", RESULT="floppy", NAME=\"%k", SYMLINK="floppy%e"

New patch is attached.

David

1 files changed, 15 insertions, 0 deletions

diff --git a/udev.8.in b/udev.8.in
index 6d1dfd9d18..9c22f8aa63 100644
--- a/udev.8.in
+++ b/udev.8.in
@@ -272,6 +272,13 @@ all remaining parts of the result string are substituted:
 .BI %s{ filename }
 The content of a sysfs attribute.
 .TP
+.B %e
+If a device node already exists with the name, the smallest positive
+decimal integer N is substituted such that the resulting name doesn't
+match an existing device node. Otherwise nothing is substituted. This
+can be used to create compatibility symlinks and enumerate devices of
+the same type originating from different kernel subsystems.
+.TP
 .B %%
 The '%' character itself.
 .P
@@ -302,6 +309,14 @@ KERNEL="ttyUSB1", NAME="pda", SYMLINK="palmtop handheld"
 
 # multiple USB webcams with symlinks to be called webcam0, webcam1, ...
 BUS="usb", SYSFS{model}="XV3", NAME="video%n", SYMLINK="webcam%n"
+
+# grouping of optical drives from multiple kernel subsystems
+KERNEL="sr*", NAME="%k", SYMLINK="cdrom%e"
+KERNEL="scd*", NAME="%k", SYMLINK="cdrom%e"
+KERNEL="pcd*", NAME="%k", SYMLINK="cdrom%e"
+KERNEL="hd[a-z]", PROGRAM="/bin/cat /proc/ide/%k/media", RESULT="cdrom",
+  NAME="%k", SYMLINK="cdrom%e"
+
 .fi
 .P
 The permissions and ownership of the created device file is read from