[RFC ] include with wildcard filenames

Ulf Samuelsson dhcp at emagii.com
Thu Mar 1 11:46:41 UTC 2018

Thank You.
Yes, the result should be in lexical order.
Will have a look at how to get it sorted.

Best Regards,
Ulf Samuelsson.

> 28 feb. 2018 kl. 23:27 skrev Timothe Litt <litt at acm.org>:
>> On 28-Feb-18 04:48, dhcp-users-request at lists.isc.org wrote:
>> Message: 1
>> Date: Tue, 27 Feb 2018 23:33:10 +0100
>> From: Ulf Samuelsson <dhcp at emagii.com>
>> To: dhcp-users at lists.isc.org
>> Subject: [RFC ] include with wildcard filenames
>> Message-ID: <f80615ed-3ae0-e5af-a62a-799842ada91a at emagii.com>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>> I was trying out a dhcpd configuration, and found to my dismay
>> that the DHCP server did not support wildcards for include statements.
>> include "/etc/dhcp/pools/*.conf";
>> did not work.
> [snip]
>> ====================================
>> I did a patch for dhcp-4.3.6 which is slightly limited.
>> It supports only wildcards on files within a single directory.
>> I.E: include "/etc/dhcp/pools/*.conf"; is supported
>> I.E: include "/etc/dhcp/*/dhcp.conf"; is not supported
>> The wildcard may not be in a directory.
>> Did a small test program which tested the functionality of wildcards,
>> and then patched the dhcp server, but it has not been tested yet, as 
>> part of dhcp
>> Still would like to have peoples opinion, whether this type of 
>> functionality is desirable.
>> It is certainly possible to do this without wildcards,
>> but wildcards seems a much cleaner solution.
>> ====================================
> [snip]
>> .
> Without commenting on your application, a note on your patch:
> You should be aware that readdir does not order the directory entries.  They are returned in
> some implementation-specific order - which is generally NOT that of a directory listing.  Commands
> such as ls sort the results for presentation.
> Users of config files in applications that have a wildcard option for include generally assume
> that the files will be included in lexical order; e.g. foo-001.conf will be included before foo-002.conf.
> This will not reliably be the case with your code.  The results will not even be deterministic on most
> platforms.
> If you pursue this, you should sort the results of readdir before including them.
> See qsort() for a fairly portable approach.  Or look at scandir() (especially with versionsort()) for
> a more convenient, if less portable approach to this.
> Timothe Litt
> ACM Distinguished Engineer
> --------------------------
> This communication may not represent the ACM or my employer's views,
> if any, on the matters discussed. 
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