[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v3 5/8] xen/hypfs: add support for id-based dynamic directories
Add some helpers to hypfs.c to support dynamic directories with a numerical id as name. The dynamic directory is based on a template specified by the user allowing to use specific access functions and having a predefined set of entries in the directory. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- V2: - use macro for length of entry name (Jan Beulich) - const attributes (Jan Beulich) - use template name as format string (Jan Beulich) - add hypfs_dynid_entry_size() helper (Jan Beulich) - expect dyndir data having been allocated by enter() callback V3: - add a specific enter() callback returning the template pointer - add data field to struct hypfs_dyndir_id - rename hypfs_gen_dyndir_entry_id() (Jan Beulich) - add comments regarding generated names to be kept in sync (Jan Beulich) Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- xen/common/hypfs.c | 98 +++++++++++++++++++++++++++++++++++++++++ xen/include/xen/hypfs.h | 18 ++++++++ 2 files changed, 116 insertions(+) diff --git a/xen/common/hypfs.c b/xen/common/hypfs.c index 8faf65cea0..087c63b92f 100644 --- a/xen/common/hypfs.c +++ b/xen/common/hypfs.c @@ -356,6 +356,104 @@ unsigned int hypfs_getsize(const struct hypfs_entry *entry) return entry->size; } +/* + * Fill the direntry for a dynamically generated directory. Especially the + * generated name needs to be kept in sync with hypfs_gen_dyndir_id_entry(). + */ +int hypfs_read_dyndir_id_entry(const struct hypfs_entry_dir *template, + unsigned int id, bool is_last, + XEN_GUEST_HANDLE_PARAM(void) *uaddr) +{ + struct xen_hypfs_dirlistentry direntry; + char name[HYPFS_DYNDIR_ID_NAMELEN]; + unsigned int e_namelen, e_len; + + e_namelen = snprintf(name, sizeof(name), template->e.name, id); + e_len = DIRENTRY_SIZE(e_namelen); + direntry.e.pad = 0; + direntry.e.type = template->e.type; + direntry.e.encoding = template->e.encoding; + direntry.e.content_len = template->e.funcs->getsize(&template->e); + direntry.e.max_write_len = template->e.max_size; + direntry.off_next = is_last ? 0 : e_len; + if ( copy_to_guest(*uaddr, &direntry, 1) ) + return -EFAULT; + if ( copy_to_guest_offset(*uaddr, DIRENTRY_NAME_OFF, name, + e_namelen + 1) ) + return -EFAULT; + + guest_handle_add_offset(*uaddr, e_len); + + return 0; +} + +static const struct hypfs_entry *hypfs_dyndir_enter( + const struct hypfs_entry *entry) +{ + const struct hypfs_dyndir_id *data; + + data = hypfs_get_dyndata(); + + /* Use template with original enter function. */ + return data->template->e.funcs->enter(&data->template->e); +} + +static struct hypfs_entry *hypfs_dyndir_findentry( + const struct hypfs_entry_dir *dir, const char *name, unsigned int name_len) +{ + const struct hypfs_dyndir_id *data; + + data = hypfs_get_dyndata(); + + /* Use template with original findentry function. */ + return data->template->e.funcs->findentry(data->template, name, name_len); +} + +static int hypfs_read_dyndir(const struct hypfs_entry *entry, + XEN_GUEST_HANDLE_PARAM(void) uaddr) +{ + const struct hypfs_dyndir_id *data; + + data = hypfs_get_dyndata(); + + /* Use template with original read function. */ + return data->template->e.funcs->read(&data->template->e, uaddr); +} + +/* + * Fill dyndata with a dynamically generated directory based on a template + * and a numerical id. + * Needs to be kept in sync with hypfs_read_dyndir_id_entry() regarding the + * name generated. + */ +struct hypfs_entry *hypfs_gen_dyndir_id_entry( + const struct hypfs_entry_dir *template, unsigned int id, void *data) +{ + struct hypfs_dyndir_id *dyndata; + + dyndata = hypfs_get_dyndata(); + + dyndata->template = template; + dyndata->id = id; + dyndata->data = data; + snprintf(dyndata->name, sizeof(dyndata->name), template->e.name, id); + dyndata->dir = *template; + dyndata->dir.e.name = dyndata->name; + dyndata->dir.e.funcs = &dyndata->funcs; + dyndata->funcs = *template->e.funcs; + dyndata->funcs.enter = hypfs_dyndir_enter; + dyndata->funcs.findentry = hypfs_dyndir_findentry; + dyndata->funcs.read = hypfs_read_dyndir; + + return &dyndata->dir.e; +} + +unsigned int hypfs_dynid_entry_size(const struct hypfs_entry *template, + unsigned int id) +{ + return DIRENTRY_SIZE(snprintf(NULL, 0, template->name, id)); +} + int hypfs_read_dir(const struct hypfs_entry *entry, XEN_GUEST_HANDLE_PARAM(void) uaddr) { diff --git a/xen/include/xen/hypfs.h b/xen/include/xen/hypfs.h index 4c469cbeb4..34073faff8 100644 --- a/xen/include/xen/hypfs.h +++ b/xen/include/xen/hypfs.h @@ -76,6 +76,17 @@ struct hypfs_entry_dir { struct list_head dirlist; }; +struct hypfs_dyndir_id { + struct hypfs_entry_dir dir; /* Modified copy of template. */ + struct hypfs_funcs funcs; /* Dynamic functions. */ + const struct hypfs_entry_dir *template; /* Template used. */ +#define HYPFS_DYNDIR_ID_NAMELEN 12 + char name[HYPFS_DYNDIR_ID_NAMELEN]; /* Name of hypfs entry. */ + + unsigned int id; /* Numerical id. */ + void *data; /* Data associated with id. */ +}; + #define HYPFS_DIR_INIT_FUNC(var, nam, fn) \ struct hypfs_entry_dir __read_mostly var = { \ .e.type = XEN_HYPFS_TYPE_DIR, \ @@ -186,6 +197,13 @@ void *hypfs_alloc_dyndata_size(unsigned long size); #define hypfs_alloc_dyndata(type) (type *)hypfs_alloc_dyndata_size(sizeof(type)) void *hypfs_get_dyndata(void); void hypfs_free_dyndata(void); +int hypfs_read_dyndir_id_entry(const struct hypfs_entry_dir *template, + unsigned int id, bool is_last, + XEN_GUEST_HANDLE_PARAM(void) *uaddr); +struct hypfs_entry *hypfs_gen_dyndir_id_entry( + const struct hypfs_entry_dir *template, unsigned int id, void *data); +unsigned int hypfs_dynid_entry_size(const struct hypfs_entry *template, + unsigned int id); #endif #endif /* __XEN_HYPFS_H__ */ -- 2.26.2
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