Re: [ndctl PATCH 4/7] daxctl: add basic config parsing support

[Dan Williams <dan.j.williams@intel.com>]

On Tue, Aug 31, 2021 at 2:05 AM Vishal Verma <vishal.l.verma@intel.com> wrote:
>
> Add support similar to ndctl and libndctl for parsing config files. This
> allows storing a config file path/list in the daxctl_ctx, and adds APIs
> for setting and retrieving it.
>
> Cc: QI Fuli <qi.fuli@fujitsu.com>
> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> ---
>  daxctl/lib/libdaxctl.c   | 37 +++++++++++++++++++++++++++++++++++++
>  daxctl/libdaxctl.h       |  2 ++
>  daxctl/Makefile.am       |  1 +
>  daxctl/lib/Makefile.am   |  4 ++++
>  daxctl/lib/libdaxctl.sym |  2 ++
>  5 files changed, 46 insertions(+)
>
> diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
> index 860bd9c..659d2fe 100644
> --- a/daxctl/lib/libdaxctl.c
> +++ b/daxctl/lib/libdaxctl.c
> @@ -17,6 +17,8 @@
>  #include <util/log.h>
>  #include <util/sysfs.h>
>  #include <util/iomem.h>
> +#include <util/strbuf.h>
> +#include <util/parse-configs.h>
>  #include <daxctl/libdaxctl.h>
>  #include "libdaxctl-private.h"
>
> @@ -37,6 +39,7 @@ struct daxctl_ctx {
>         struct log_ctx ctx;
>         int refcount;
>         void *userdata;
> +       const char *configs;
>         int regions_init;
>         struct list_head regions;
>         struct kmod_ctx *kmod_ctx;
> @@ -68,6 +71,40 @@ DAXCTL_EXPORT void daxctl_set_userdata(struct daxctl_ctx *ctx, void *userdata)
>         ctx->userdata = userdata;
>  }
>
> +DAXCTL_EXPORT void daxctl_set_configs(struct daxctl_ctx **ctx, char *conf_dir)
> +{
> +       struct dirent **namelist;
> +       struct strbuf value = STRBUF_INIT;
> +       int rc;
> +
> +       if ((!ctx) || (!conf_dir))
> +               return;
> +
> +       rc = scandir(conf_dir, &namelist, filter_conf_files, alphasort);
> +       if (rc == -1) {
> +               perror("scandir");
> +               return;
> +       }
> +
> +       while (rc--) {
> +               if (value.len)
> +                       strbuf_addstr(&value, " ");
> +               strbuf_addstr(&value, conf_dir);
> +               strbuf_addstr(&value, "/");
> +               strbuf_addstr(&value, namelist[rc]->d_name);
> +               free(namelist[rc]);
> +       }
> +       (*ctx)->configs = strbuf_detach(&value, NULL);
> +       free(namelist);
> +}
> +
> +DAXCTL_EXPORT const char *daxctl_get_configs(struct daxctl_ctx *ctx)
> +{
> +       if (ctx == NULL)
> +               return NULL;
> +       return ctx->configs;
> +}
> +
>  /**
>   * daxctl_new - instantiate a new library context
>   * @ctx: context to establish
> diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
> index 683ae9c..9388f85 100644
> --- a/daxctl/libdaxctl.h
> +++ b/daxctl/libdaxctl.h
> @@ -28,6 +28,8 @@ int daxctl_get_log_priority(struct daxctl_ctx *ctx);
>  void daxctl_set_log_priority(struct daxctl_ctx *ctx, int priority);
>  void daxctl_set_userdata(struct daxctl_ctx *ctx, void *userdata);
>  void *daxctl_get_userdata(struct daxctl_ctx *ctx);
> +void daxctl_set_configs(struct daxctl_ctx **ctx, char *conf_dir);
> +const char *daxctl_get_configs(struct daxctl_ctx *ctx);
>
>  struct daxctl_region;
>  struct daxctl_region *daxctl_new_region(struct daxctl_ctx *ctx, int id,
> diff --git a/daxctl/Makefile.am b/daxctl/Makefile.am
> index 9b1313a..a9845a0 100644
> --- a/daxctl/Makefile.am
> +++ b/daxctl/Makefile.am
> @@ -10,6 +10,7 @@ config.h: $(srcdir)/Makefile.am
>                 "$(daxctl_modprobe_datadir)/$(daxctl_modprobe_data)"' >>$@ && \
>         echo '#define DAXCTL_MODPROBE_INSTALL \
>                 "$(sysconfdir)/modprobe.d/$(daxctl_modprobe_data)"' >>$@
> +       $(AM_V_GEN) echo '#define DAXCTL_CONF_DIR  "$(ndctl_confdir)"' >>$@

This gets back to my namespace question about collisions between
daxctl, ndctl, and cxl-cli conf snippets. I think they should each get
their own directory in /etc, then we don't need to encode any prefixes
into section names. What do you think?