Re: [ndctl PATCH 6/7] daxctl/device.c: add an option for getting params from a config file

["Verma, Vishal L" <vishal.l.verma@intel.com>]

On Thu, 2021-09-16 at 18:59 -0700, Dan Williams wrote:
> On Tue, Aug 31, 2021 at 2:05 AM Vishal Verma <vishal.l.verma@intel.com> wrote:
> > 
> > Add a new option to daxctl-reconfigure-device that allows it to
> > comprehend the new global config system in ndctl/daxctl. With this, the
> > reconfigure-device command can query the config to match a specific
> > device UUID, and operate using the parameters supplied in that INI
> > section.
> > 
> > This is in preparation to make daxctl device reconfiguration (usually
> > as system-ram) policy based, so that reconfiguration can happen
> > automatically on boot.
> > 
> > Cc: QI Fuli <qi.fuli@fujitsu.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
> > ---
> >  daxctl/daxctl.c    |   1 +
> >  daxctl/device.c    | 141 ++++++++++++++++++++++++++++++++++++++++++++-
> >  daxctl/Makefile.am |   1 +
> >  3 files changed, 142 insertions(+), 1 deletion(-)
> > 
> > diff --git a/daxctl/daxctl.c b/daxctl/daxctl.c
> > index 928814c..dc7ac5f 100644
> > --- a/daxctl/daxctl.c
> > +++ b/daxctl/daxctl.c
> > @@ -95,6 +95,7 @@ int main(int argc, const char **argv)
> >         rc = daxctl_new(&ctx);
> >         if (rc)
> >                 goto out;
> > +       daxctl_set_configs(&ctx, DAXCTL_CONF_DIR);
> 
> Now that I see how this is used, I think this wants to be called:
> 
> daxctl_ctx_add_configs()
> 
> ...because the operation is populating the context with all the
> configuration fragments found in the given directory.
> 
> I would also have an option to specify an override for the config
> directory, maybe that could be an environment variable?

Hm, the concern with _add_configs is that is sounds like we're
additively adding multiple directories containing config files, which
isn't true - this (currently at least) supports only one directory at a
time - hence 'set'.

Maybe daxctl_set_configs_dir() is more appropriate?

> 
> >         main_handle_internal_command(argc, argv, ctx, commands,
> >                         ARRAY_SIZE(commands), PROG_DAXCTL);
> >         daxctl_unref(ctx);
> > diff --git a/daxctl/device.c b/daxctl/device.c
> > index a427b7d..99a4548 100644
> > --- a/daxctl/device.c
> > +++ b/daxctl/device.c
> > @@ -14,8 +14,10 @@
> >  #include <util/filter.h>
> >  #include <json-c/json.h>
> >  #include <json-c/json_util.h>
> > +#include <ndctl/libndctl.h>
> >  #include <daxctl/libdaxctl.h>
> >  #include <util/parse-options.h>
> > +#include <util/parse-configs.h>
> >  #include <ccan/array_size/array_size.h>
> > 
> >  static struct {
> > @@ -25,6 +27,7 @@ static struct {
> >         const char *size;
> >         const char *align;
> >         const char *input;
> > +       bool check_config;
> >         bool no_online;
> >         bool no_movable;
> >         bool force;
> > @@ -75,7 +78,9 @@ OPT_STRING('m', "mode", &param.mode, "mode", "mode to switch the device to"), \
> >  OPT_BOOLEAN('N', "no-online", &param.no_online, \
> >         "don't auto-online memory sections"), \
> >  OPT_BOOLEAN('f', "force", &param.force, \
> > -               "attempt to offline memory sections before reconfiguration")
> > +               "attempt to offline memory sections before reconfiguration"), \
> > +OPT_BOOLEAN('C', "check-config", &param.check_config, \
> > +               "use config files to determine parameters for the operation")
> > 
> >  #define CREATE_OPTIONS() \
> >  OPT_STRING('s', "size", &param.size, "size", "size to switch the device to"), \
> > @@ -218,6 +223,130 @@ err:
> >         return rc;
> >  }
> > 
> > +static int conf_string_to_bool(const char *str)
> > +{
> > +       if (!str)
> > +               return INT_MAX;
> > +       if (strncmp(str, "t", 1) == 0 ||
> > +                       strncmp(str, "T", 1) == 0 ||
> > +                       strncmp(str, "y", 1) == 0 ||
> > +                       strncmp(str, "Y", 1) == 0 ||
> > +                       strncmp(str, "1", 1) == 0)
> > +               return true;
> > +       if (strncmp(str, "f", 1) == 0 ||
> > +                       strncmp(str, "F", 1) == 0 ||
> > +                       strncmp(str, "n", 1) == 0 ||
> > +                       strncmp(str, "N", 1) == 0 ||
> > +                       strncmp(str, "0", 1) == 0)
> > +               return false;
> 
> Doesn't iniparser_getboolean() already do this conversion for you?

It does.. but the API provided by parse-configs.h, specifically the
CONF_SEARCH macro only deals in strings. I would probably need to add a
CONF_SEARCH_BOOL to return booleans, that then internally uses
iniparser_getboolean.

> 
> > +       return INT_MAX;
> > +}
> > +
> > +#define conf_assign_inverted_bool(p, conf_var) \
> > +do { \
> > +       if (conf_string_to_bool(conf_var) != INT_MAX) \
> > +               param.p = !conf_string_to_bool(conf_var); \
> > +} while(0)
> > +
> > +static int parse_config_reconfig_set_params(struct daxctl_ctx *ctx, const char *device,
> > +                                           const char *uuid)
> > +{
> > +       const char *conf_online = NULL, *conf_movable = NULL;
> > +       const struct config configs[] = {
> > +               CONF_SEARCH("auto-online", "uuid", uuid, "mode", &param.mode, NULL),
> > +               CONF_SEARCH("auto-online", "uuid", uuid, "online", &conf_online, NULL),
> > +               CONF_SEARCH("auto-online", "uuid", uuid, "movable", &conf_movable, NULL),
> > +               CONF_END(),
> > +       };
> > +       const char *prefix = "./";
> > +       int rc;
> > +
> > +       rc = parse_configs_prefix(daxctl_get_configs(ctx), prefix, configs);
> > +       if (rc < 0)
> > +               return rc;
> > +
> > +       conf_assign_inverted_bool(no_online, conf_online);
> > +       conf_assign_inverted_bool(no_movable, conf_movable);
> > +
> > +       return 0;
> > +}
> > +
> > +static bool daxctl_ndns_has_device(struct ndctl_namespace *ndns,
> > +                                   const char *device)
> > +{
> > +       struct daxctl_region *dax_region;
> > +       struct ndctl_dax *dax;
> > +
> > +       dax = ndctl_namespace_get_dax(ndns);
> > +       if (!dax)
> > +               return false;
> > +
> > +       dax_region = ndctl_dax_get_daxctl_region(dax);
> > +       if (dax_region) {
> > +               struct daxctl_dev *dev;
> > +
> > +               dev = daxctl_dev_get_first(dax_region);
> > +               if (dev) {
> > +                       if (strcmp(daxctl_dev_get_devname(dev), device) == 0)
> > +                               return true;
> > +               }
> > +       }
> > +       return false;
> > +}
> > +
> > +static int parse_config_reconfig(struct daxctl_ctx *ctx, const char *device)
> > +{
> > +       struct ndctl_namespace *ndns;
> > +       struct ndctl_ctx *ndctl_ctx;
> > +       struct ndctl_region *region;
> > +       struct ndctl_bus *bus;
> > +       struct ndctl_dax *dax;
> > +       int rc, found = 0;
> > +       char uuid_buf[40];
> > +       uuid_t uuid;
> > +
> > +       if (strcmp(device, "all") == 0)
> > +               return 0;
> > +
> > +       rc = ndctl_new(&ndctl_ctx);
> > +       if (rc < 0)
> > +               return rc;
> > +
> > +        ndctl_bus_foreach(ndctl_ctx, bus) {
> > +               ndctl_region_foreach(bus, region) {
> > +                       ndctl_namespace_foreach(region, ndns) {
> > +                               if (daxctl_ndns_has_device(ndns, device)) {
> > +                                       dax = ndctl_namespace_get_dax(ndns);
> > +                                       if (!dax)
> > +                                               continue;
> > +                                       ndctl_dax_get_uuid(dax, uuid);
> > +                                       found = 1;
> > +                               }
> > +                       }
> > +               }
> > +       }
> > +
> > +       if (!found) {
> > +               fprintf(stderr, "no UUID match for %s found in config files\n",
> > +                       device);
> > +               return 0;
> > +       }
> > +
> > +       uuid_unparse(uuid, uuid_buf);
> > +       return parse_config_reconfig_set_params(ctx, device, uuid_buf);
> > +}
> > +
> > +static int parse_device_config(struct daxctl_ctx *ctx, const char *device,
> > +                              enum device_action action)
> > +{
> > +       switch (action) {
> > +       case ACTION_RECONFIG:
> > +               return parse_config_reconfig(ctx, device);
> > +       default:
> > +               return 0;
> > +       }
> > +}
> > +
> >  static const char *parse_device_options(int argc, const char **argv,
> >                 enum device_action action, const struct option *options,
> >                 const char *usage, struct daxctl_ctx *ctx)
> > @@ -279,6 +408,16 @@ static const char *parse_device_options(int argc, const char **argv,
> >         if (param.human)
> >                 flags |= UTIL_JSON_HUMAN;
> > 
> > +       /* Scan config file(s) for options. This sets param.foo accordingly */
> > +       if (param.check_config) {
> > +               rc = parse_device_config(ctx, argv[0], action);
> 
> What happens if someone does:
> 
> daxctl reconfigure-device -C --no-online /dev/dax0.0
> 
> ...and it matches an entry in the configuration file that has
> "system-ram.online = true".
> 
> My expectation is that precedence ordering is:
> 
> built-in defaults
> configuration file settings
> command line options
> 
> Where later entries in that list override settings from the previous
> entry. That said, I don't see an easy way to achieve this with parse
> options, so might need to fail if anything but -C is specified as an
> option until we can fix that conflict.

Yeah I struggled with this too :)  The precedence ordering makes sense,
and I wanted to implement that as well, but it wasn't wasily possible
with the param stuffing without a larger rework. Bailing on a mismatch
makes sense though, I'll add that.

> 
> > +               if (rc) {
> > +                       fprintf(stderr, "error parsing config file: %s\n",
> > +                               strerror(-rc));
> > +                       return NULL;
> > +               }
> > +       }
> > +
> >         /* Handle action-specific options */
> >         switch (action) {
> >         case ACTION_RECONFIG:
> > diff --git a/daxctl/Makefile.am b/daxctl/Makefile.am
> > index a9845a0..f30c485 100644
> > --- a/daxctl/Makefile.am
> > +++ b/daxctl/Makefile.am
> > @@ -23,6 +23,7 @@ daxctl_SOURCES =\
> > 
> >  daxctl_LDADD =\
> >         lib/libdaxctl.la \
> > +       ../ndctl/lib/libndctl.la \
> >         ../libutil.a \
> >         $(UUID_LIBS) \
> >         $(KMOD_LIBS) \
> > --
> > 2.31.1
> >