add "[$SUBSYSTEM/$KERNEL]<attribute>" lookup

[elogind.git] / udev_sysfs.c

diff --git a/udev_sysfs.c b/udev_sysfs.c
index 1846a42f6accd18be58a73297a81119b179713c3..98be9a5352e9f7807ce6c4c72a24d925389f04ff 100644 (file)
--- a/udev_sysfs.c
+++ b/udev_sysfs.c
@@ -429,3 +429,94 @@ char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
 out:
        return attr->value;
 }
+
+int sysfs_lookup_devpath_by_subsys_id(char *devpath_full, size_t len, const char *subsystem, const char *id)
+{
+       size_t sysfs_len;
+       char path_full[PATH_SIZE];
+       char *path;
+       struct stat statbuf;
+
+       sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
+       path = &path_full[sysfs_len];
+
+       if (strcmp(subsystem, "subsystem") == 0) {
+               strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
+               strlcat(path, id, sizeof(path_full) - sysfs_len);
+               if (stat(path_full, &statbuf) == 0)
+                       goto found;
+
+               strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
+               strlcat(path, id, sizeof(path_full) - sysfs_len);
+               if (stat(path_full, &statbuf) == 0)
+                       goto found;
+               goto out;
+
+               strlcpy(path, "/class/", sizeof(path_full) - sysfs_len);
+               strlcat(path, id, sizeof(path_full) - sysfs_len);
+               if (stat(path_full, &statbuf) == 0)
+                       goto found;
+       }
+
+       if (strcmp(subsystem, "module") == 0) {
+               strlcpy(path, "/module/", sizeof(path_full) - sysfs_len);
+               strlcat(path, id, sizeof(path_full) - sysfs_len);
+               if (stat(path_full, &statbuf) == 0)
+                       goto found;
+               goto out;
+       }
+
+       if (strcmp(subsystem, "drivers") == 0) {
+               char subsys[NAME_SIZE];
+               char *driver;
+
+               strlcpy(subsys, id, sizeof(subsys));
+               driver = strchr(subsys, ':');
+               if (driver != NULL) {
+                       driver[0] = '\0';
+                       driver = &driver[1];
+                       strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
+                       strlcat(path, subsys, sizeof(path_full) - sysfs_len);
+                       strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len);
+                       strlcat(path, driver, sizeof(path_full) - sysfs_len);
+                       if (stat(path_full, &statbuf) == 0)
+                               goto found;
+
+                       strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
+                       strlcat(path, subsys, sizeof(path_full) - sysfs_len);
+                       strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len);
+                       strlcat(path, driver, sizeof(path_full) - sysfs_len);
+                       if (stat(path_full, &statbuf) == 0)
+                               goto found;
+               }
+               goto out;
+       }
+
+       strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len);
+       strlcat(path, subsystem, sizeof(path_full) - sysfs_len);
+       strlcat(path, "/devices/", sizeof(path_full) - sysfs_len);
+       strlcat(path, id, sizeof(path_full) - sysfs_len);
+       if (stat(path_full, &statbuf) == 0)
+               goto found;
+
+       strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len);
+       strlcat(path, subsystem, sizeof(path_full) - sysfs_len);
+       strlcat(path, "/devices/", sizeof(path_full) - sysfs_len);
+       strlcat(path, id, sizeof(path_full) - sysfs_len);
+       if (stat(path_full, &statbuf) == 0)
+               goto found;
+
+       strlcpy(path, "/class/", sizeof(path_full) - sysfs_len);
+       strlcat(path, subsystem, sizeof(path_full) - sysfs_len);
+       strlcat(path, "/", sizeof(path_full) - sysfs_len);
+       strlcat(path, id, sizeof(path_full) - sysfs_len);
+       if (stat(path_full, &statbuf) == 0)
+               goto found;
+out:
+       return 0;
+found:
+       if (S_ISLNK(statbuf.st_mode))
+               sysfs_resolve_link(path, sizeof(path_full) - sysfs_len);
+       strlcpy(devpath_full, path, len);
+       return 1;
+}