diff options
| -rw-r--r-- | udev.h | 1 | ||||
| -rw-r--r-- | udev_sysfs.c | 70 |
2 files changed, 45 insertions, 26 deletions
@@ -54,6 +54,7 @@ struct udev_rules; struct sysfs_device { struct list_head node; /* for device cache */ + struct sysfs_device *parent; /* already cached parent*/ char devpath[PATH_SIZE]; char subsystem[NAME_SIZE]; /* $class/$bus/"drivers" */ char kernel_name[NAME_SIZE]; /* device instance name */ diff --git a/udev_sysfs.c b/udev_sysfs.c index 8de523dadf..b579c17caa 100644 --- a/udev_sysfs.c +++ b/udev_sysfs.c @@ -40,7 +40,8 @@ static LIST_HEAD(attr_list); struct sysfs_attr { struct list_head node; char path[PATH_SIZE]; - char value[NAME_SIZE]; + char *value; /* points to value_local if value is cached */ + char value_local[NAME_SIZE]; }; int sysfs_init(void) @@ -126,14 +127,21 @@ struct sysfs_device *sysfs_device_get(const char *devpath) strlcpy(devpath_real, devpath, sizeof(devpath_real)); remove_trailing_chars(devpath_real, '/'); + /* look for device already in cache (we never put an untranslated path in the cache) */ + list_for_each_entry(dev_loop, &dev_list, node) { + if (strcmp(dev_loop->devpath, devpath_real) == 0) { + dbg("found in cache '%s'", dev_loop->devpath); + return dev_loop; + } + } + + /* if we got a link, resolve it to the real device */ strlcpy(path, sysfs_path, sizeof(path)); strlcat(path, devpath_real, sizeof(path)); if (lstat(path, &statbuf) != 0) { dbg("stat '%s' failed: %s", path, strerror(errno)); return NULL; } - - /* if we got a link, resolve it to the real device */ if (S_ISLNK(statbuf.st_mode)) { int i; int back; @@ -156,17 +164,17 @@ struct sysfs_device *sysfs_device_get(const char *devpath) dbg("after moving back '%s'", devpath_real); strlcat(devpath_real, "/", sizeof(devpath_real)); strlcat(devpath_real, &link_target[back * 3], sizeof(devpath_real)); - } - /* look for device in cache */ - list_for_each_entry(dev_loop, &dev_list, node) { - if (strcmp(dev_loop->devpath, devpath_real) == 0) { - dbg("found in cache '%s'", dev_loop->devpath); - return dev_loop; + /* now look for device in cache after path translation */ + list_for_each_entry(dev_loop, &dev_list, node) { + if (strcmp(dev_loop->devpath, devpath_real) == 0) { + dbg("found in cache '%s'", dev_loop->devpath); + return dev_loop; + } } } - /* new device */ + /* it is a new device */ dbg("'%s'", devpath_real); dev = malloc(sizeof(struct sysfs_device)); if (dev == NULL) @@ -245,6 +253,9 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev) int len; int back; + if (dev->parent != NULL) + return dev->parent; + /* requesting a parent is only valid for devices */ if ((strncmp(dev->devpath, "/devices/", 9) != 0) && (strncmp(dev->devpath, "/class/", 7) != 0) && @@ -266,12 +277,11 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev) return NULL; } - /* at the top level we may follow the "device" link */ + /* at the top level of class/block we want to follow the "device" link */ if (strcmp(parent_devpath, "/block") == 0) { dbg("/block top level, look for device link"); goto device_link; } - if (strncmp(parent_devpath, "/class", 6) == 0) { pos = strrchr(parent_devpath, '/'); if (pos == &parent_devpath[6] || pos == parent_devpath) { @@ -279,7 +289,8 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev) goto device_link; } } - return sysfs_device_get(parent_devpath); + dev->parent = sysfs_device_get(parent_devpath); + return dev->parent; device_link: strlcpy(device_link, sysfs_path, sizeof(device_link)); @@ -304,7 +315,9 @@ device_link: dbg("after moving back '%s'", parent_devpath); strlcat(parent_devpath, "/", sizeof(parent_devpath)); strlcat(parent_devpath, &device_link_target[back * 3], sizeof(parent_devpath)); - return sysfs_device_get(parent_devpath); + + dev->parent = sysfs_device_get(parent_devpath); + return dev->parent; } struct sysfs_device *sysfs_device_get_parent_with_subsystem(struct sysfs_device *dev, const char *subsystem) @@ -345,27 +358,32 @@ char *sysfs_attr_get_value(const char *devpath, const char *attr_name) } } + /* store attribute in cache (also negatives are kept in cache) */ + attr = malloc(sizeof(struct sysfs_attr)); + if (attr == NULL) + return NULL; + memset(attr, 0x00, sizeof(struct sysfs_attr)); + strlcpy(attr->path, path, sizeof(attr->path)); + dbg("add to cache '%s' '%s'", attr->path, attr->value); + list_add(&attr->node, &attr_list); + /* read attribute value */ fd = open(path_full, O_RDONLY); if (fd < 0) - return NULL; + goto out; size = read(fd, value, sizeof(value)); close(fd); if (size < 0) - return NULL; + goto out; if (size == sizeof(value)) - return NULL; + goto out; + + /* got a valid value, store and return it */ value[size] = '\0'; remove_trailing_chars(value, '\n'); + strlcpy(attr->value_local, value, sizeof(attr->value_local)); + attr->value = attr->value_local; - /* store attribute in cache */ - attr = malloc(sizeof(struct sysfs_attr)); - if (attr == NULL) - return NULL; - strlcpy(attr->path, path, sizeof(attr->path)); - strlcpy(attr->value, value, sizeof(attr->value)); - dbg("add to cache '%s' '%s'", attr->path, attr->value); - list_add(&attr->node, &attr_list); - +out: return attr->value; } |