add basic udev device enumeration module

Makefile

@@ -1,5 +1,5 @@
-CFLAGS=-Wall -Wextra -O0 -g -pipe -D_GNU_SOURCE -fdiagnostics-show-option -Wno-unused-parameter -DUNIT_PATH=\"/tmp/does/not/exist\"
-LIBS=-lrt -lcap
+CFLAGS=-Wall -Wextra -O0 -g -pipe -D_GNU_SOURCE -fdiagnostics-show-option -Wno-unused-parameter -DUNIT_PATH=\"/tmp/does/not/exist\" `pkg-config --cflags libudev`
+LIBS=-lrt -lcap `pkg-config --libs libudev`
 
 COMMON= \
 	unit.o \

device.c

@@ -1,14 +1,18 @@
 /*-*- Mode: C; c-basic-offset: 8 -*-*/
 
+#include <errno.h>
+#include <libudev.h>
+
 #include "unit.h"
 #include "device.h"
 #include "strv.h"
+#include "log.h"
 
 static void device_done(Unit *u) {
         Device *d = DEVICE(u);
 
         assert(d);
-        strv_free(d->sysfs);
+        free(d->sysfs);
 }
 
 static void device_dump(Unit *u, FILE *f, const char *prefix) {
@@ -18,13 +22,207 @@ static void device_dump(Unit *u, FILE *f, const char *prefix) {
                 [DEVICE_AVAILABLE] = "available"
         };
 
-        Device *s = DEVICE(u);
+        Device *d = DEVICE(u);
 
-        assert(s);
+        assert(d);
 
         fprintf(f,
-                "%sDevice State: %s\n",
-                prefix, state_table[s->state]);
+                "%sDevice State: %s\n"
+                "%sSysfs Path: %s\n",
+                prefix, state_table[d->state],
+                prefix, d->sysfs);
+}
+
+static int device_add_escaped_name(Unit *u, const char *dn) {
+        char *e;
+        int r;
+
+        assert(u);
+        assert(dn);
+        assert(dn[0] == '/');
+
+        if (!(e = unit_name_escape_path(dn+1, ".device")))
+                return -ENOMEM;
+
+        r = unit_add_name(u, e);
+        free(e);
+
+        if (r < 0 && r != -EEXIST)
+                return r;
+
+        return 0;
+}
+
+static int device_process_device(Manager *m, struct udev_device *dev) {
+        const char *dn, *names, *wants, *sysfs;
+        Unit *u = NULL;
+        int r;
+        char *e, *w, *state;
+        size_t l;
+        bool delete;
+        struct udev_list_entry *item = NULL, *first = NULL;
+
+        assert(m);
+
+        /* Check whether this entry is even relevant for us. */
+        dn = udev_device_get_devnode(dev);
+        names = udev_device_get_property_value(dev, "SYSTEMD_NAMES");
+        wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS");
+
+        if (!dn && !names && !wants)
+                return 0;
+
+        /* Ok, seems kinda interesting. Now, let's see if this one
+         * already exists. */
+
+        if (!(sysfs = udev_device_get_syspath(dev)))
+                return -ENOMEM;
+
+        assert(sysfs[0] == '/');
+        if (!(e = unit_name_escape_path(sysfs+1, ".device")))
+                return -ENOMEM;
+
+        if (!(u = manager_get_unit(m, e))) {
+                const char *model;
+
+                delete = true;
+
+                if (!(u = unit_new(m))) {
+                        free(e);
+                        return -ENOMEM;
+                }
+
+                r = unit_add_name(u, e);
+                free(e);
+
+                if (r < 0)
+                        goto fail;
+
+                if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
+                     (model = udev_device_get_property_value(dev, "ID_MODEL")))
+                        if (!(u->meta.description = strdup(model))) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+        } else {
+                delete = false;
+                free(e);
+        }
+
+        if (dn)
+                if ((r = device_add_escaped_name(u, dn)) < 0)
+                        goto fail;
+
+        first = udev_device_get_devlinks_list_entry(dev);
+        udev_list_entry_foreach(item, first)
+                if ((r = device_add_escaped_name(u, udev_list_entry_get_name(item))) < 0)
+                        goto fail;
+
+        if (names) {
+                FOREACH_WORD(w, l, names, state) {
+                        if (!(e = strndup(w, l)))
+                                goto fail;
+
+                        r = unit_add_name(u, e);
+                        free(e);
+
+                        if (r < 0 && r != -EEXIST)
+                                goto fail;
+                }
+        }
+
+
+        if (set_isempty(u->meta.names)) {
+                r = -EEXIST;
+                goto fail;
+        }
+
+        if (wants) {
+                FOREACH_WORD(w, l, wants, state) {
+                        if (!(e = strndup(w, l)))
+                                goto fail;
+
+                        r = unit_add_dependency_by_name(u, UNIT_WANTS, e);
+                        free(e);
+
+                        if (r < 0)
+                                goto fail;
+                }
+        }
+
+        unit_add_to_load_queue(u);
+        return 0;
+
+fail:
+        if (delete && u)
+                unit_free(u);
+        return r;
+}
+
+static int device_process_path(Manager *m, const char *path) {
+        int r;
+        struct udev_device *dev;
+
+        assert(m);
+        assert(path);
+
+        if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
+                log_warning("Failed to get udev device object from udev for path %s.", path);
+                return -ENOMEM;
+        }
+
+        r = device_process_device(m, dev);
+        udev_device_unref(dev);
+        return r;
+}
+
+static void device_shutdown(Manager *m) {
+        assert(m);
+
+        if (m->udev)
+                udev_unref(m->udev);
+}
+
+static int device_enumerate(Manager *m) {
+        int r;
+        struct udev_enumerate *e = NULL;
+        struct udev_list_entry *item = NULL, *first = NULL;
+
+        assert(m);
+
+        if (!(m->udev = udev_new()))
+                return -ENOMEM;
+
+        if (!(e = udev_enumerate_new(m->udev))) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        if (udev_enumerate_scan_devices(e) < 0) {
+                r = -EIO;
+                goto fail;
+        }
+
+        first = udev_enumerate_get_list_entry(e);
+        udev_list_entry_foreach(item, first)
+                device_process_path(m, udev_list_entry_get_name(item));
+
+        udev_enumerate_unref(e);
+
+        return 0;
+
+fail:
+        if (e)
+                udev_enumerate_unref(e);
+
+        device_shutdown(m);
+        return r;
 }
 
 static UnitActiveState device_active_state(Unit *u) {
@@ -38,5 +236,8 @@ const UnitVTable device_vtable = {
         .done = device_done,
         .dump = device_dump,
 
+        .enumerate = device_enumerate,
+        .shutdown = device_shutdown,
+
         .active_state = device_active_state
 };

device.h

@@ -21,7 +21,7 @@ struct Device {
         DeviceState state;
 
         /* A single device can be created by multiple sysfs objects */
-        char **sysfs;
+        char *sysfs;
 };
 
 extern const UnitVTable device_vtable;

manager.h

@@ -70,6 +70,8 @@ struct Manager {
         Watch signal_watch;
 
         Unit *special_units[_SPECIAL_UNIT_MAX]; /* some special units */
+
+        struct udev* udev;
 };
 
 Manager* manager_new(void);