#include <fcntl.h>
#include <ctype.h>
#include <errno.h>
+#include <sys/stat.h>
#include "udev.h"
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)
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", devpath, strerror(errno));
+ 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;
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 */
- dbg("'%s'", devpath_real);
+ /* it is a new device */
+ dbg("new uncached device '%s'", devpath_real);
dev = malloc(sizeof(struct sysfs_device));
if (dev == NULL)
return NULL;
pos[0] = '\0';
else
dev->subsystem[0] = '\0';
- } else if (strncmp(devpath, "/block/", 7) == 0) {
+ } else if (strncmp(dev->devpath, "/block/", 7) == 0) {
strlcpy(dev->subsystem, "block", sizeof(dev->subsystem));
- } else if (strncmp(devpath, "/devices/", 9) == 0) {
- /* get subsystem from bus name */
+ } else if (strncmp(dev->devpath, "/devices/", 9) == 0) {
+ /* get subsystem from "bus" link */
strlcpy(link_path, sysfs_path, sizeof(link_path));
strlcat(link_path, dev->devpath, sizeof(link_path));
strlcat(link_path, "/bus", sizeof(link_path));
pos = strrchr(link_target, '/');
if (pos != NULL)
strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
+ } else {
+ /* get subsystem from "subsystem" link */
+ strlcpy(link_path, sysfs_path, sizeof(link_path));
+ strlcat(link_path, dev->devpath, sizeof(link_path));
+ strlcat(link_path, "/subsystem", sizeof(link_path));
+ len = readlink(link_path, link_target, sizeof(link_target));
+ if (len > 0) {
+ link_target[len] = '\0';
+ dbg("subsystem link '%s' points to '%s'", link_path, link_target);
+ pos = strrchr(link_target, '/');
+ if (pos != NULL)
+ strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
+ }
}
-
/* get driver name */
strlcpy(link_path, sysfs_path, sizeof(link_path));
strlcat(link_path, dev->devpath, sizeof(link_path));
if (pos != NULL)
strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
}
- } else if (strncmp(devpath, "/bus/", 5) == 0 && strstr(devpath, "/drivers/")) {
+ } else if (strncmp(dev->devpath, "/bus/", 5) == 0 && strstr(dev->devpath, "/drivers/")) {
strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
- } else if (strncmp(devpath, "/module/", 8) == 0) {
+ } else if (strncmp(dev->devpath, "/module/", 8) == 0) {
strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
}
int len;
int back;
+ dbg("open '%s'", dev->devpath);
+
+ /* look if we already know the parent */
+ 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) &&
return NULL;
pos[0] = '\0';
- /* are we at the top level */
+ /* are we at the top level of /devices */
if (strcmp(parent_devpath, "/devices") == 0) {
dbg("/devices top level");
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) {
- dbg("class top level, look for device link");
+ dbg("/class top level, look for device link");
goto device_link;
}
}
- return sysfs_device_get(parent_devpath);
+ /* get parent and remember it */
+ dev->parent = sysfs_device_get(parent_devpath);
+ return dev->parent;
device_link:
strlcpy(device_link, sysfs_path, sizeof(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);
+
+ /* get parent and remember it */
+ 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)
+{
+ struct sysfs_device *dev_parent;
+
+ dev_parent = sysfs_device_get_parent(dev);
+ while (dev_parent != NULL) {
+ if (strcmp(dev_parent->subsystem, subsystem) == 0)
+ return dev_parent;
+ dev_parent = sysfs_device_get_parent(dev_parent);
+ }
+ return NULL;
}
char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
ssize_t size;
size_t sysfs_len;
+ dbg("open '%s'/'%s'", devpath, attr_name);
sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
path = &path_full[sysfs_len];
strlcat(path_full, devpath, sizeof(path_full));
}
}
+ /* store attribute in cache (also negatives are kept in cache) */
+ dbg("new uncached attribute '%s'", path_full);
+ 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'", path_full);
+ list_add(&attr->node, &attr_list);
+
/* read attribute value */
fd = open(path_full, O_RDONLY);
- if (fd < 0)
- return NULL;
+ if (fd < 0) {
+ dbg("attribute '%s' does not exist", path_full);
+ 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');
+ dbg("cache '%s' with value '%s'", path_full, value);
+ 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;
}