Dear Raphael, I fixed the problem. The issue was that I used a slash at the end of the path which I set here: ret = aug_set(myAug, "/augeas/load/Interfaces/incl", path);
Example: /etc/network/interfaces/ instead of /etc/network/interfaces There was no error message generated but augeas just did not save the changes back to the file. I uploaded a working example to my git repo: https://github.com/cmolitor/AugeasDemoC Maybe it is helpful for someone else. Thanks and best regards, Christoph Am 11.01.2016 um 09:38 schrieb Raphaël Pinson <raphael.pin...@camptocamp.com>: > Hello Christoph, > > > > On Sun, Jan 10, 2016 at 6:09 PM, Christoph Molitor > <christoph.moli...@googlemail.com> wrote: > Hello Raphaël, > > thanks for your reply and your suggestions. > I added some code to read the error messages. > When I execute the code there are no error messages but still the changes > made to the value of one node are not saved back to the configuration file. > The latest source code can be found here: > https://github.com/cmolitor/AugeasDemoC/blob/simple/src/main.cpp > > > You need to really look into how to use XPath in Augeas. You can remove > pretty much all of > https://github.com/cmolitor/AugeasDemoC/blob/simple/src/main.cpp#L93-L111 > (and probably more) by using proper XPath expressions instead of manually > parsing the tree node by node. > > > Also, Augeas 1.0.0 introduced aug_transform, which is easier/better than > manually manipulating nodes in /augeas/load. > > > > I also went through all the steps using augtool and added the commands as > comments to the source code. > If I execute the commands in augtool the changes are saved to the > configuration file. > > In general, I can load the configuration file, change the value, check that > the value has been really changed by reading it again. Calling aug_save() > does not give an error message but still the changes are not saved to the > file. > > > And what is the output of your code then? > > > I tried this with augeas version 1.2 and 1.4. > > It would be great if I could get further advice how to proceed or a hint what > I am doing wrong. > > I will also have a look at netcf but could not find a detailed documentation > yet. > > > netcf has been used for a few years in libvirt. See > https://github.com/saaros/libvirt/blob/master/src/interface/interface_backend_netcf.c > for example. > > > > Cheers, > > Raphaël > > > > Am 04.01.2016 um 09:44 schrieb Raphaël Pinson <raphael.pin...@camptocamp.com>: > >> Hello Christoph and happy new year to you too! >> >> >> Your code doesn't check for errors (either parsing or saving errors). You >> could add checks (looking for `/augeas//error` nodes) just after your call >> to aug_load (for parsing errors) and to aug_save (for saving errors). >> >> One way to debug your code would also be to try it with augtool, which would >> be easier to debug. >> >> Also, are you aware of the netcf project, which provides a higher API on top >> of Augeas to access and modify /etc/network/interfaces? >> >> >> >> Cheers, >> >> Raphaël >> >> >> >> >> >> On Fri, Jan 1, 2016 at 5:05 PM, Christoph Molitor >> <christoph.moli...@googlemail.com> wrote: >> Dear all, >> >> first of all a happy new year to everyone. >> >> I am trying to use the augeas C API to apply changes to the >> "/etc/network/interfaces" file. >> So far I was able to apply changes to the tree. However, I am not able to >> save the changes back to the file. >> First, I thought it is a problem with the permissions. However, I copied the >> interfaces file to a different folder and it still does not work. >> Using the command line tool augtool, I am able to make the changes and save >> them to the file. >> >> I uploaded an (almost) minimal version of my program to: >> https://github.com/cmolitor/AugeasDemoC >> >> The repository includes an example „interfaces“. >> I am working on a Raspberry Pi with Raspbian Jessie. >> It would be great if someone could give me a hint what I am doing work and >> where the problem might come from. >> >> Thanks for your support! >> >> Christoph >> >> _______________________________________________ >> augeas-devel mailing list >> augeas-devel@redhat.com >> https://www.redhat.com/mailman/listinfo/augeas-devel >> >> >> >> -- >> Raphaël Pinson >> Infrastructure Developer & Training Leader >> +33 458 482 013 >> >> Camptocamp France >> Savoie Technolac >> BP 352 >> 48, avenue du Lac du Bourget >> 73372 Le Bourget du Lac, Cedex >> www.camptocamp.com > > > > > -- > Raphaël Pinson > Infrastructure Developer & Training Leader > +33 458 482 013 > > Camptocamp France > Savoie Technolac > BP 352 > 48, avenue du Lac du Bourget > 73372 Le Bourget du Lac, Cedex > www.camptocamp.com
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