Get defaults from udev for Screen FB plugin and Gamma,Dpms DRM plugin…

…. Moreover, emit Dpms,Gamma.Changed signals overriding displayId if empty (in drm case); ie: avoid emitting a Gamma.Changed signal on empty id.

README.md

@@ -2,7 +2,13 @@
 
 [![Packaging status](https://repology.org/badge/vertical-allrepos/clightd.svg)](https://repology.org/project/clightd/versions)
 
-Clightd is a bus interface that lets you easily set screen brightness, gamma temperature and get ambient brightness through webcam frames capture or ALS devices.
+Clightd is a bus interface that lets you easily set/get screen brightness, gamma temperature and display dpms state.  
+Moreover, it enables getting ambient brightness through webcam frames capture or ALS devices.  
+
+It works on both X, Wayland and tty.  
+On wayland specific protocols need to be implemented by your compositor; have a look at {Gamma, Dpms, Screen} wiki pages.  
+
+Clightd is used as a backend by [Clight](https://github.com/FedeDP/Clight) but it can be used without it too.  
 
 **For a guide on how to build, features and lots of other infos, refer to [Clightd Wiki Pages](https://github.com/FedeDP/Clightd/wiki).**  
 **Note that Wiki pages will always refer to master branch.**  

TODO.md

@@ -67,6 +67,7 @@
 - [x] Add new deps to wiki (libwayland-dev on ubuntu, wayland on arch and wayland-devel on fedora) + libdrm + libjpeg-turbo + libusb
 - [x] Fix: second call to get an open wl_display does not need XDG_RUNTIME_DIR properly set
 - [x] Moved to LIBEXECDIR intead of LIBDIR (#52 PR #53)
+- [x] For DRM and FB plugins -> override empty display variable with one got through libudev, this way Changed signal is emitted on proper device -> eg:
 
 ## 4.X
 - [ ] Keep it up to date with possible ddcutil/libmodule api changes

src/commons.h

@@ -20,7 +20,7 @@
 #define _ctor_     __attribute__((constructor (101))) // Used for Sensors registering
 #define _dtor_     __attribute__((destructor (101)))  // Used for libusb dtor
 
-/* Used by dpms, gamm  and screen*/
+/* Used by dpms, gamma and screen*/
 #define UNSUPPORTED             INT_MIN 
 #define WRONG_PLUGIN            INT_MIN + 1
 #define COMPOSITOR_NO_PROTOCOL  INT_MIN + 2

src/modules/dpms.c

@@ -94,15 +94,22 @@ static int method_getdpms(sd_bus_message *m, void *userdata, sd_bus_error *ret_e
         return r;
     }
 
+    /*
+     * Note: this is freed by drm plugin if it is an empty string
+     * to get a default drm device.
+     */
+    const char *dpy = strdup(display);
     dpms_plugin *plugin = userdata;
     int dpms_state = WRONG_PLUGIN;
     if (!plugin) {
         for (int i = 0; i < DPMS_NUM && dpms_state == WRONG_PLUGIN; i++) {
-            dpms_state = plugins[i]->get(display, env);
+            dpms_state = plugins[i]->get(&dpy, env);
         }
     } else {
-        dpms_state = plugin->get(display, env);
+        dpms_state = plugin->get(&dpy, env);
     }
+    free((char *)dpy);
+
     if (dpms_state < 0) {
         switch (dpms_state) {
         case COMPOSITOR_NO_PROTOCOL:
@@ -141,15 +148,20 @@ static int method_setdpms(sd_bus_message *m, void *userdata, sd_bus_error *ret_e
         return -EINVAL;
     }
 
+    /*
+     * Note: this is freed by drm plugin if it is an empty string
+     * to get a default drm device.
+     */
+    const char *dpy = strdup(display);
     dpms_plugin *plugin = userdata;
     int err = WRONG_PLUGIN;
     if (!plugin) {
         for (int i = 0; i < DPMS_NUM && err == WRONG_PLUGIN; i++) {
             plugin = plugins[i];
-            err = plugin->set(display, env, level);
+            err = plugin->set(&dpy, env, level);
         }
     } else {
-        err = plugin->set(display, env, level);
+        err = plugin->set(&dpy, env, level);
     }
     if (err) {
         switch (err) {
@@ -163,13 +175,15 @@ static int method_setdpms(sd_bus_message *m, void *userdata, sd_bus_error *ret_e
             sd_bus_error_set_const(ret_error, SD_BUS_ERROR_FAILED, "Failed to set dpms level.");
             break;
         }
-        return -EACCES;
+        err = -EACCES;
+    } else {
+        m_log("New dpms state: %d.\n", level);
+        sd_bus_emit_signal(bus, object_path, bus_interface, "Changed", "si", dpy, level);
+        sd_bus_emit_signal(bus, plugin->obj_path, bus_interface, "Changed", "si", dpy, level);
+        err = sd_bus_reply_method_return(m, "b", true);
     }
-
-    m_log("New dpms state: %d.\n", level);
-    sd_bus_emit_signal(bus, object_path, bus_interface, "Changed", "si", display, level);
-    sd_bus_emit_signal(bus, plugin->obj_path, bus_interface, "Changed", "si", display, level);
-    return sd_bus_reply_method_return(m, "b", true);
+    free((char *)dpy);
+    return err;
 }
 
 #endif

src/modules/dpms.h

@@ -12,16 +12,20 @@ enum dpms_plugins {
     DPMS_NUM
 };
 
+/* 
+ * set() and get() take double pointer as 
+ * drm plugin may override id.
+ */
 typedef struct {
     const char *name;
-    int (*set)(const char *id, const char *env, int level);
-    int (*get)(const char *id, const char *env);
+    int (*set)(const char **id, const char *env, int level);
+    int (*get)(const char **id, const char *env);
     char obj_path[100];
 } dpms_plugin;
 
 #define DPMS(name) \
-    static int get(const char *id, const char *env); \
-    static int set(const char *id, const char *env, int level); \
+    static int get(const char **id, const char *env); \
+    static int set(const char **id, const char *env, int level); \
     static void _ctor_ register_gamma_plugin(void) { \
         static dpms_plugin self = { name, set, get }; \
         dpms_register_new(&self); \

src/modules/dpms_plugins/drm.c

@@ -16,7 +16,7 @@ DPMS("Drm");
  * 
  * Clightd returns -1 if dpms is disabled
  */
-static int get(const char *card, const char *env) {
+static int get(const char **card, const char *env) {
     int state = -1;
     drmModeConnectorPtr connector;
 
@@ -43,12 +43,14 @@ static int get(const char *card, const char *env) {
             }
         }
         drmModeFreeResources(res);
+    } else {
+        perror("dpms drmModeGetResources");
     }
     close(fd);
     return state;
 }
 
-static int set(const char *card, const char *env, int level) {
+static int set(const char **card, const char *env, int level) {
     int err = 0;
     drmModeConnectorPtr connector;
     drmModePropertyPtr prop;

src/modules/dpms_plugins/wl.c

@@ -153,8 +153,8 @@ static void destroy_node(struct output *output) {
     free(output);
 }
 
-static int get(const char *display, const char *env) {
-    int ret = wl_init(display, env);
+static int get(const char **display, const char *env) {
+    int ret = wl_init(*display, env);
     if (ret == 0) {
         struct output *output;
          wl_list_for_each(output, &outputs, link) {
@@ -167,8 +167,8 @@ static int get(const char *display, const char *env) {
     return ret;
 }
 
-static int set(const char *display, const char *env, int level) {
-    int ret = wl_init(display, env);
+static int set(const char **display, const char *env, int level) {
+    int ret = wl_init(*display, env);
      if (ret == 0) {
         struct output *output;
         wl_list_for_each(output, &outputs, link) {

src/modules/dpms_plugins/xorg.c

@@ -12,14 +12,14 @@ DPMS("Xorg");
  * 2     DPMSModeSuspend     Blanked, lower power
  * 3     DPMSModeOff         Shut off, awaiting activity
  */
-static int get(const char *display, const char *xauthority) {
+static int get(const char **display, const char *xauthority) {
     BOOL onoff;
     CARD16 s;
     int ret = WRONG_PLUGIN;
 
     setenv("XAUTHORITY", xauthority, 1);
 
-    Display *dpy = XOpenDisplay(display);
+    Display *dpy = XOpenDisplay(*display);
     if (dpy) {
         if (DPMSCapable(dpy)) {
             DPMSInfo(dpy, &s, &onoff);
@@ -34,13 +34,13 @@ static int get(const char *display, const char *xauthority) {
     return ret;
 }
 
-static int set(const char *display, const char *xauthority, int dpms_level) {
+static int set(const char **display, const char *xauthority, int dpms_level) {
     int ret = WRONG_PLUGIN;
 
     /* set xauthority cookie */
     setenv("XAUTHORITY", xauthority, 1);
 
-    Display *dpy = XOpenDisplay(display);
+    Display *dpy = XOpenDisplay(*display);
     if (dpy) {
         if (DPMSCapable(dpy)) {
             DPMSEnable(dpy);

src/modules/gamma.c

@@ -247,8 +247,8 @@ static void client_dtor(void *c) {
         cl->plugin->dtor(cl->priv);
     }
     free(cl->priv);
-    free(cl->display);
-    free(cl->env);
+    free((char *)cl->display);
+    free((char *)cl->env);
     free(cl);
 }
 
@@ -352,10 +352,10 @@ static gamma_client *fetch_client(gamma_plugin *plugin, const char *display, con
             *err = WRONG_PLUGIN;
             for (int i = 0; i < GAMMA_NUM && *err == WRONG_PLUGIN; i++) {
                 plugin = plugins[i];
-                *err = plugin->validate(cl->display, cl->env, &cl->priv);
+                *err = plugin->validate(&cl->display, cl->env, &cl->priv);
             }
         } else {
-            *err = plugin->validate(cl->display, cl->env, &cl->priv);
+            *err = plugin->validate(&cl->display, cl->env, &cl->priv);
         }
         if (*err != 0) {
             client_dtor(cl);

src/modules/gamma.h

@@ -24,24 +24,28 @@ typedef struct _gamma_cl {
     unsigned int smooth_step;
     unsigned int smooth_wait;
     unsigned int current_temp;
-    char *display;
-    char *env;
+    const char *display;
+    const char *env;
     int fd;
     struct _gamma_plugin *plugin;
     void *priv;
 } gamma_client;
 
+/* 
+ * validate() takes double pointer as 
+ * drm plugin may override id.
+ */
 typedef struct _gamma_plugin {
     const char *name;
-    int (*validate)(const char *id, const char *env, void **priv_data);
+    int (*validate)(const char **id, const char *env, void **priv_data);
     int (*set)(void *priv_data, const int temp);
     int (*get)(void *priv_data);
     int (*dtor)(void *priv_data);
     char obj_path[100];
 } gamma_plugin;
 
 #define GAMMA(name) \
-    static int validate(const char *id, const char *env, void **priv_data); \
+    static int validate(const char **id, const char *env, void **priv_data); \
     static int set(void *priv_data, const int temp); \
     static int get(void *priv_data); \
     static int dtor(void *priv_data); \

src/modules/gamma_plugins/drm.c

@@ -9,7 +9,7 @@ typedef struct {
 
 GAMMA("Drm");
 
-static int validate(const char *id, const char *env, void **priv_data) {
+static int validate(const char **id, const char *env, void **priv_data) {
     int ret = WRONG_PLUGIN;
     int fd = drm_open_card(id);
     if (fd < 0) {
@@ -28,6 +28,7 @@ static int validate(const char *id, const char *env, void **priv_data) {
             ret = -ENOMEM;
         }
     } else {
+        perror("gamma drmModeGetResources");
         ret = UNSUPPORTED;
     }
 

src/modules/gamma_plugins/wl.c

@@ -41,8 +41,8 @@ static const struct wl_registry_listener registry_listener = {
 
 GAMMA("Wl");
 
-static int validate(const char *id, const char *env,  void **priv_data) {
-    struct wl_display *display = fetch_wl_display(id, env);
+static int validate(const char **id, const char *env,  void **priv_data) {
+    struct wl_display *display = fetch_wl_display(*id, env);
     if (display == NULL) {
         return WRONG_PLUGIN;
     }

src/modules/gamma_plugins/xorg.c

@@ -9,12 +9,12 @@ typedef struct {
 
 GAMMA("Xorg");
 
-static int validate(const char *id, const char *env, void **priv_data) {
+static int validate(const char **id, const char *env, void **priv_data) {
     int ret = WRONG_PLUGIN;
 
     setenv("XAUTHORITY", env, 1);
 
-    Display *dpy = XOpenDisplay(id);
+    Display *dpy = XOpenDisplay(*id);
     if (dpy) {
         int screen = DefaultScreen(dpy);
         Window root = RootWindow(dpy, screen);

src/modules/screen_plugins/fb.c

@@ -1,8 +1,9 @@
 #include "screen.h"
 #include <linux/fb.h> /* to handle framebuffer ioctls */
 #include <sys/ioctl.h>
+#include "udev.h"
 
-#define DEFAULT_FB "/dev/fb0"
+#define FB_SUBSYSTEM "graphics"
 
 static int get_framebufferdata(int fd, struct fb_var_screeninfo *fb_varinfo_p, struct fb_fix_screeninfo *fb_fixedinfo);
 static int read_framebuffer(int fd, size_t bytes, unsigned char *buf_p, int skip_bytes);
@@ -11,16 +12,23 @@ SCREEN("Fb")
 
 /* Many thanks to fbgrab utility: https://github.com/GunnarMonell/fbgrab/blob/master/fbgrab.c */
 static int get_frame_brightness(const char *id, const char *env) {
-     if (!id || !strlen(id)) {
-         id = DEFAULT_FB;
+    int ret = WRONG_PLUGIN;
+
+    struct udev_device *dev = NULL;
+    if (!id || !strlen(id)) {
+        /* Fetch first matching device from udev */
+        get_udev_device(NULL, FB_SUBSYSTEM, NULL, NULL, &dev);
+        if (!dev) {
+            return ret;
+        }
+        id = udev_device_get_devnode(dev);
     }
 
-    int ret = WRONG_PLUGIN;
     unsigned char *buf_p = NULL;
     int fd = open(id, O_RDONLY);
     if (fd == -1) {
         fprintf(stderr, "Error: Couldn't open %s.\n", id);
-        return ret;
+        goto err;
     }
 
     ret = UNSUPPORTED;
@@ -62,6 +70,9 @@ static int get_frame_brightness(const char *id, const char *env) {
     if (fd != -1) {
         close(fd);
     }
+    if (dev) {
+        udev_device_unref(dev);
+    }
     return ret;
 }
 

src/utils/drm_utils.c

@@ -2,14 +2,27 @@
 
 #include "drm_utils.h"
 #include "commons.h"
+#include "udev.h"
 
-#define DEFAULT_DRM "/dev/dri/card0"
+#define DRM_SUBSYSTEM "drm"
 
-int drm_open_card(const char *card) {
-    if (!card || !strlen(card)) {
-        card = DEFAULT_DRM;
+int drm_open_card(const char **card) {
+    if (!*card || !strlen(*card)) {
+        /* Fetch first matching device from udev */
+        struct udev_device *dev = NULL;
+        get_udev_device(NULL, DRM_SUBSYSTEM, NULL, NULL, &dev);
+        if (!dev) {
+            return -ENOENT;
+        }
+
+        /* Free old value */
+        free((char *)*card);
+
+        /* Store new value */
+        *card = strdup(udev_device_get_devnode(dev));
+        udev_device_unref(dev);
     }
-    int fd = open(card, O_RDWR | O_CLOEXEC);
+    int fd = open(*card, O_RDWR | O_CLOEXEC);
     if (fd < 0) {
         perror("open");
     }

src/utils/drm_utils.h

@@ -1,4 +1,4 @@
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
-int drm_open_card(const char *card_num);
+int drm_open_card(const char **card_num);