On Wed, Sep 16, 2020 at 05:37:12PM +0200, [email protected] wrote: > From: Martin Wilck <[email protected]> > > Add an implementation of get_multipath_config() and put_multipath_config() > to libmultipath. The linker's symbol lookup rules will make sure that > applications can override these functions if they need to. Defining > these functions in libmultipath avoids the need to provide stubs > for these functions in every appliation linking to libmultipath. > > libmultipath's internal functions simply refer to a static "struct config". > It must be initialized with init_config() rather than load_config(), > which always allocates a new struct for backward compatibility. > free_config() can be used in both cases.
free_config() doesn't actually work for configs that are initialized by init_config(). That's fine, but the commit message is wrong. Also, I wonder if uninit_config() should zero out __internal_config, so that it's in the same state as it was before init_config() is called. -Ben > > Signed-off-by: Martin Wilck <[email protected]> > --- > libmultipath/config.c | 70 ++++++++++++++++++++++++++++++++++++------- > libmultipath/config.h | 21 +++++++++++-- > 2 files changed, 78 insertions(+), 13 deletions(-) > > diff --git a/libmultipath/config.c b/libmultipath/config.c > index 2011a29..b83e5cd 100644 > --- a/libmultipath/config.c > +++ b/libmultipath/config.c > @@ -27,6 +27,23 @@ > #include "mpath_cmd.h" > #include "propsel.h" > > +static struct config __internal_config; > +struct config *libmp_get_multipath_config(void) > +{ > + return &__internal_config; > +} > + > +struct config *get_multipath_config(void) > + __attribute__((weak, alias("libmp_get_multipath_config"))); > + > +void libmp_put_multipath_config(void *conf __attribute__((unused))) > +{ > + /* empty */ > +} > + > +void put_multipath_config(void *conf) > + __attribute__((weak, alias("libmp_put_multipath_config"))); > + > static int > hwe_strmatch (const struct hwentry *hwe1, const struct hwentry *hwe2) > { > @@ -574,17 +591,15 @@ restart: > return; > } > > -struct config * > -alloc_config (void) > +static struct config *alloc_config (void) > { > return (struct config *)MALLOC(sizeof(struct config)); > } > > -void > -free_config (struct config * conf) > +static void _uninit_config(struct config *conf) > { > if (!conf) > - return; > + conf = &__internal_config; > > if (conf->multipath_dir) > FREE(conf->multipath_dir); > @@ -650,7 +665,25 @@ free_config (struct config * conf) > free_hwtable(conf->hwtable); > free_hwe(conf->overrides); > free_keywords(conf->keywords); > - FREE(conf); > +} > + > +void uninit_config(void) > +{ > + _uninit_config(&__internal_config); > +} > + > +void free_config(struct config *conf) > +{ > + if (!conf) > + return; > + else if (conf == &__internal_config) { > + condlog(0, "ERROR: %s called for internal config. Use > uninit_config() instead", > + __func__); > + return; > + } > + > + _uninit_config(conf); > + free(conf); > } > > /* if multipath fails to process the config directory, it should continue, > @@ -719,12 +752,29 @@ static void set_max_checkint_from_watchdog(struct > config *conf) > } > #endif > > +static int _init_config (const char *file, struct config *conf); > + > +int init_config(const char *file) > +{ > + return _init_config(file, &__internal_config); > +} > + > struct config *load_config(const char *file) > { > struct config *conf = alloc_config(); > > + if (conf && !_init_config(file, conf)) > + return conf; > + > + free(conf); > + return NULL; > +} > + > +int _init_config (const char *file, struct config *conf) > +{ > + > if (!conf) > - return NULL; > + conf = &__internal_config; > > /* > * internal defaults > @@ -896,10 +946,10 @@ struct config *load_config(const char *file) > !conf->wwids_file || !conf->prkeys_file) > goto out; > > - return conf; > + return 0; > out: > - free_config(conf); > - return NULL; > + _uninit_config(conf); > + return 1; > } > > char *get_uid_attribute_by_attrs(struct config *conf, > diff --git a/libmultipath/config.h b/libmultipath/config.h > index 116fe37..5997b71 100644 > --- a/libmultipath/config.h > +++ b/libmultipath/config.h > @@ -251,10 +251,25 @@ void free_mptable (vector mptable); > int store_hwe (vector hwtable, struct hwentry *); > > struct config *load_config (const char *file); > -struct config * alloc_config (void); > void free_config (struct config * conf); > -extern struct config *get_multipath_config(void); > -extern void put_multipath_config(void *); > +int init_config(const char *file); > +void uninit_config(void); > + > +/* > + * libmultipath provides default implementations of > + * get_multipath_config() and put_multipath_config(). > + * Applications using these should use init_config(file, NULL) > + * to load the configuration, rather than load_config(file). > + * Likewise, uninit_config() should be used for teardown, but > + * using free_config() for that is supported, too. > + * Applications can define their own {get,put}_multipath_config() > + * functions, which override the library-internal ones, but > + * could still call libmp_{get,put}_multipath_config(). > + */ > +struct config *libmp_get_multipath_config(void); > +struct config *get_multipath_config(void); > +void libmp_put_multipath_config(void *); > +void put_multipath_config(void *); > > int parse_uid_attrs(char *uid_attrs, struct config *conf); > char *get_uid_attribute_by_attrs(struct config *conf, > -- > 2.28.0 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
