From f180ad259f1480a3d58106e38eb760f79600e0e1 Mon Sep 17 00:00:00 2001 From: Thomas Egerer Date: Fri, 4 Mar 2011 17:06:41 +0100 Subject: [PATCH] libudev: allow to get list of all available sysfs attrs for a device Signed-off-by: Thomas Egerer --- libudev/exported_symbols | 1 + libudev/libudev-device.c | 81 ++++++++++++++++++++++++++++++++++++++++ libudev/libudev.h | 1 + 3 files changed, 83 insertions(+) diff --git a/libudev/exported_symbols b/libudev/exported_symbols index 2e6a9b7dc..500e98158 100644 --- a/libudev/exported_symbols +++ b/libudev/exported_symbols @@ -32,6 +32,7 @@ udev_device_get_is_initialized udev_device_get_devlinks_list_entry udev_device_get_properties_list_entry udev_device_get_tags_list_entry +udev_device_get_sysattr_list_entry udev_device_get_property_value udev_device_get_action udev_device_get_driver diff --git a/libudev/libudev-device.c b/libudev/libudev-device.c index 16bee19df..af0bc2e5a 100644 --- a/libudev/libudev-device.c +++ b/libudev/libudev-device.c @@ -61,6 +61,7 @@ struct udev_device { struct udev_list_node devlinks_list; struct udev_list_node properties_list; struct udev_list_node sysattr_list; + struct udev_list_node available_sysattr_list; struct udev_list_node tags_list; unsigned long long int seqnum; unsigned long long int usec_initialized; @@ -83,6 +84,7 @@ struct udev_device { bool db_loaded; bool uevent_loaded; bool is_initialized; + bool sysattrs_cached; }; struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device, const char *key, const char *value) @@ -361,6 +363,7 @@ struct udev_device *udev_device_new(struct udev *udev) udev_list_init(&udev_device->devlinks_list); udev_list_init(&udev_device->properties_list); udev_list_init(&udev_device->sysattr_list); + udev_list_init(&udev_device->available_sysattr_list); udev_list_init(&udev_device->tags_list); udev_device->event_timeout = -1; udev_device->watch_handle = -1; @@ -785,6 +788,7 @@ void udev_device_unref(struct udev_device *udev_device) udev_list_cleanup_entries(udev_device->udev, &udev_device->devlinks_list); udev_list_cleanup_entries(udev_device->udev, &udev_device->properties_list); udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list); + udev_list_cleanup_entries(udev_device->udev, &udev_device->available_sysattr_list); udev_list_cleanup_entries(udev_device->udev, &udev_device->tags_list); free(udev_device->action); free(udev_device->driver); @@ -1235,6 +1239,83 @@ out: return val; } +static int udev_device_cache_sysattrs(struct udev_device *udev_device) +{ + struct dirent *entry; + DIR *dir; + int num = 0; + + if (udev_device == NULL) + return -1; + /* caching already done? */ + if (udev_device->sysattrs_cached) + return 0; + + dir = opendir(udev_device_get_syspath(udev_device)); + if (!dir) { + dbg(udev_device->udev, "sysfs dir '%s' can not be opened\n", + udev_device_get_syspath(udev_device)); + return -1; + } + + while (NULL != (entry = readdir(dir))) { + char path[UTIL_PATH_SIZE]; + struct stat statbuf; + + /* only handle symlinks and regular files */ + if (DT_LNK != entry->d_type && DT_REG != entry->d_type) + continue; + + util_strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), + "/", entry->d_name, NULL); + if (0 != lstat(path, &statbuf)) + continue; + + if (0 == (statbuf.st_mode & S_IRUSR)) + continue; + + if (DT_LNK == entry->d_type) { + if (strcmp(entry->d_name, "driver") != 0 && + strcmp(entry->d_name, "subsystem") != 0 && + strcmp(entry->d_name, "module") != 0) + continue; + } + udev_list_entry_add(udev_device->udev, + &udev_device->available_sysattr_list, entry->d_name, + DT_LNK == entry->d_type ? "s" : "r", 0, 0); + ++num; + } + + dbg(udev_device->udev, "found %d sysattrs for '%s'\n", num, + udev_device_get_syspath(udev_device)); + udev_device->sysattrs_cached = true; + + return num; +} + +/** + * udev_device_get_sysattr_list_entry: + * @udev_device: udev device + * + * Retrieve the list of available sysattrs, with value being empty; + * This is to be able to read all available sysfs attributes for a particular + * device without the necessity to access sysfs from outside libudev. + * + * Returns: the first entry of the property list + **/ +struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device) +{ + /* perform initial caching of sysattr list */ + if (!udev_device->sysattrs_cached) { + int ret; + ret = udev_device_cache_sysattrs(udev_device); + if (0 > ret) + return NULL; + } + + return udev_list_get_entry(&udev_device->available_sysattr_list); +} + int udev_device_set_syspath(struct udev_device *udev_device, const char *syspath) { const char *pos; diff --git a/libudev/libudev.h b/libudev/libudev.h index 0abd7c8b0..892530b77 100644 --- a/libudev/libudev.h +++ b/libudev/libudev.h @@ -92,6 +92,7 @@ int udev_device_get_is_initialized(struct udev_device *udev_device); struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device); struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device); struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device); +struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device); const char *udev_device_get_property_value(struct udev_device *udev_device, const char *key); const char *udev_device_get_driver(struct udev_device *udev_device); dev_t udev_device_get_devnum(struct udev_device *udev_device); -- 2.30.2