sd-device: device_id - set correctly for 'drivers'

The 'drivers' pseudo-subsystem needs special treatment. These pseudo-devices are found under /sys/bus/drivers/, so needs the real subsystem encoded in the device_id in order to be resolved. The reader side already assumed this to be the case.
2016-06-27 09:54:20 +02:00
parent 3172836b2f
commit de7e983ea1
2 changed files with 72 additions and 14 deletions
@@ -76,6 +76,8 @@ struct sd_device {

        char *subsystem;
        bool subsystem_set; /* don't reread subsystem */
+        char *driver_subsystem; /* only set for the 'drivers' subsystem */
+        bool driver_subsystem_set; /* don't reread subsystem */
        char *driver;
        bool driver_set; /* don't reread driver */

@@ -75,6 +75,7 @@ _public_ sd_device *sd_device_unref(sd_device *device) {
                free(device->devtype);
                free(device->devname);
                free(device->subsystem);
+                free(device->driver_subsystem);
                free(device->driver);
                free(device->id_filename);
                free(device->properties_strv);
@@ -766,21 +767,45 @@ int device_set_subsystem(sd_device *device, const char *_subsystem) {
        return 0;
 }

+static int device_set_drivers_subsystem(sd_device *device, const char *_subsystem) {
+        _cleanup_free_ char *subsystem = NULL;
+        int r;
+
+        assert(device);
+        assert(_subsystem);
+        assert(*_subsystem);
+
+        subsystem = strdup(_subsystem);
+        if (!subsystem)
+                return -ENOMEM;
+
+        r = device_set_subsystem(device, "drivers");
+        if (r < 0)
+                return r;
+
+        free(device->driver_subsystem);
+        device->driver_subsystem = subsystem;
+        subsystem = NULL;
+
+        return 0;
+}
+
 _public_ int sd_device_get_subsystem(sd_device *device, const char **ret) {
+        const char *syspath, *drivers = NULL;
+        int r;
+
        assert_return(ret, -EINVAL);
        assert_return(device, -EINVAL);

+        r = sd_device_get_syspath(device, &syspath);
+        if (r < 0)
+                return r;
+
        if (!device->subsystem_set) {
                _cleanup_free_ char *subsystem = NULL;
-                const char *syspath;
                char *path;
-                int r;

                /* read 'subsystem' link */
-                r = sd_device_get_syspath(device, &syspath);
-                if (r < 0)
-                        return r;
-
                path = strjoina(syspath, "/subsystem");
                r = readlink_value(path, &subsystem);
                if (r >= 0)
@@ -788,16 +813,39 @@ _public_ int sd_device_get_subsystem(sd_device *device, const char **ret) {
                /* use implicit names */
                else if (path_startswith(device->devpath, "/module/"))
                        r = device_set_subsystem(device, "module");
-                else if (strstr(device->devpath, "/drivers/"))
-                        r = device_set_subsystem(device, "drivers");
-                else if (path_startswith(device->devpath, "/subsystem/") ||
-                         path_startswith(device->devpath, "/class/") ||
-                         path_startswith(device->devpath, "/bus/"))
+                else if (!(drivers = strstr(syspath, "/drivers/")) &&
+                         (path_startswith(device->devpath, "/subsystem/") ||
+                          path_startswith(device->devpath, "/class/") ||
+                          path_startswith(device->devpath, "/bus/")))
                        r = device_set_subsystem(device, "subsystem");
                if (r < 0 && r != -ENOENT)
                        return log_debug_errno(r, "sd-device: could not set subsystem for %s: %m", device->devpath);

                device->subsystem_set = true;
+        } else if (!device->driver_subsystem_set)
+                drivers = strstr(syspath, "/drivers/");
+
+        if (!device->driver_subsystem_set) {
+                if (drivers) {
+                        _cleanup_free_ char *subpath = NULL;
+
+                        subpath = strndup(syspath, drivers - syspath);
+                        if (!subpath)
+                                r = -ENOMEM;
+                        else {
+                                const char *subsys;
+
+                                subsys = strrchr(subpath, '/');
+                                if (!subsys)
+                                        r = -EINVAL;
+                                else
+                                        r = device_set_drivers_subsystem(device, subsys + 1);
+                        }
+                        if (r < 0 && r != -ENOENT)
+                                return log_debug_errno(r, "sd-device: could not set subsystem for driver %s: %m", device->devpath);
+                }
+
+                device->driver_subsystem_set = true;
        }

        if (!device->subsystem)
@@ -1234,9 +1282,17 @@ int device_get_id_filename(sd_device *device, const char **ret) {
                        if (!subsystem)
                                return -EINVAL;

-                        r = asprintf(&id, "+%s:%s", subsystem, sysname);
-                        if (r < 0)
-                                return -ENOMEM;
+                        if (streq(subsystem, "drivers")) {
+                                /* the 'drivers' pseudo-subsystem is special, and needs the real subsystem
+                                 * encoded as well */
+                                r = asprintf(&id, "+drivers:%s:%s", device->driver_subsystem, sysname);
+                                if (r < 0)
+                                        return -ENOMEM;
+                        } else {
+                                r = asprintf(&id, "+%s:%s", subsystem, sysname);
+                                if (r < 0)
+                                        return -ENOMEM;
+                        }
                }

                device->id_filename = id;