terminal: add systemd-modeset debugging tool

The systemd-modeset tool is meant to debug grdev issues. It simply
displays morphing colors on any found display. This is pretty handy to
look for tearing in the backends and debug hotplug issues.

Note that this tool requires systemd-logind to be compiled from git
(there're important fixes that haven't been released, yet).

3 files changed, 506 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index f8650870a3..288946029b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -90,6 +90,7 @@
 /systemd-logind
 /systemd-machine-id-setup
 /systemd-machined
+/systemd-modeset
 /systemd-modules-load
 /systemd-multi-seat-x
 /systemd-networkd
diff --git a/Makefile.am b/Makefile.am
index be25023c75..f80ffc6749 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -2987,6 +2987,7 @@ noinst_LTLIBRARIES += \
 
 noinst_PROGRAMS += \
 	systemd-evcat \
+	systemd-modeset \
 	systemd-subterm
 
 unifontdatadir=$(datadir)/unifont
@@ -3045,6 +3046,19 @@ systemd_evcat_LDADD = \
 	libsystemd-shared.la \
 	$(TERMINAL_LIBS)
 
+systemd_modeset_CFLAGS = \
+	$(AM_CFLAGS) \
+	$(TERMINAL_CFLAGS)
+
+systemd_modeset_SOURCES = \
+	src/libsystemd-terminal/modeset.c
+
+systemd_modeset_LDADD = \
+	libsystemd-terminal.la \
+	libsystemd-internal.la \
+	libsystemd-shared.la \
+	$(TERMINAL_LIBS)
+
 systemd_subterm_SOURCES = \
 	src/libsystemd-terminal/subterm.c
 
diff --git a/src/libsystemd-terminal/modeset.c b/src/libsystemd-terminal/modeset.c
new file mode 100644
index 0000000000..02ed1a8987
--- /dev/null
+++ b/src/libsystemd-terminal/modeset.c
@@ -0,0 +1,491 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright (C) 2014 David Herrmann <dh.herrmann@gmail.com>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+/*
+ * Modeset Testing
+ * The modeset tool attaches to the session of the caller and shows a
+ * test-pattern on all displays of this session. It is meant as debugging tool
+ * for the grdev infrastructure.
+ */
+
+#include <drm_fourcc.h>
+#include <errno.h>
+#include <getopt.h>
+#include <linux/kd.h>
+#include <linux/vt.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <systemd/sd-bus.h>
+#include <systemd/sd-event.h>
+#include <systemd/sd-login.h>
+#include <termios.h>
+#include <unistd.h>
+#include "build.h"
+#include "bus-util.h"
+#include "event-util.h"
+#include "grdev.h"
+#include "grdev-internal.h"
+#include "macro.h"
+#include "sysview.h"
+#include "util.h"
+
+typedef struct Modeset Modeset;
+
+struct Modeset {
+        char *session;
+        char *seat;
+        sd_event *event;
+        sd_bus *bus;
+        sd_event_source *exit_src;
+        sysview_context *sysview;
+        grdev_context *grdev;
+        grdev_session *grdev_session;
+
+        uint8_t r, g, b;
+        bool r_up, g_up, b_up;
+
+        bool my_tty : 1;
+        bool managed : 1;
+};
+
+static int modeset_exit_fn(sd_event_source *source, void *userdata) {
+        Modeset *m = userdata;
+
+        if (m->grdev_session)
+                grdev_session_restore(m->grdev_session);
+
+        return 0;
+}
+
+static Modeset *modeset_free(Modeset *m) {
+        if (!m)
+                return NULL;
+
+        m->grdev_session = grdev_session_free(m->grdev_session);
+        m->grdev = grdev_context_unref(m->grdev);
+        m->sysview = sysview_context_free(m->sysview);
+        m->exit_src = sd_event_source_unref(m->exit_src);
+        m->bus = sd_bus_unref(m->bus);
+        m->event = sd_event_unref(m->event);
+        free(m->seat);
+        free(m->session);
+        free(m);
+
+        return NULL;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(Modeset*, modeset_free);
+
+static bool is_my_tty(const char *session) {
+        unsigned int vtnr;
+        struct stat st;
+        long mode;
+        int r;
+
+        /* Using logind's Controller API is highly fragile if there is already
+         * a session controller running. If it is registered as controller
+         * itself, TakeControl will simply fail. But if its a legacy controller
+         * that does not use logind's controller API, we must never register
+         * our own controller. Otherwise, we really mess up the VT. Therefore,
+         * only run in managed mode if there's no-one else.  Furthermore, never
+         * try to access graphics devices if there's someone else. Unlike input
+         * devices, graphics devies cannot be shared easily. */
+
+        if (!isatty(1))
+                return false;
+
+        if (!session)
+                return false;
+
+        r = sd_session_get_vt(session, &vtnr);
+        if (r < 0 || vtnr < 1 || vtnr > 63)
+                return false;
+
+        mode = 0;
+        r = ioctl(1, KDGETMODE, &mode);
+        if (r < 0 || mode != KD_TEXT)
+                return false;
+
+        r = fstat(1, &st);
+        if (r < 0 || minor(st.st_rdev) != vtnr)
+                return false;
+
+        return true;
+}
+
+static int modeset_new(Modeset **out) {
+        _cleanup_(modeset_freep) Modeset *m = NULL;
+        int r;
+
+        assert(out);
+
+        m = new0(Modeset, 1);
+        if (!m)
+                return log_oom();
+
+        r = sd_pid_get_session(getpid(), &m->session);
+        if (r < 0) {
+                log_error("Cannot retrieve logind session: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_session_get_seat(m->session, &m->seat);
+        if (r < 0) {
+                log_error("Cannot retrieve seat of logind session: %s", strerror(-r));
+                return r;
+        }
+
+        m->my_tty = is_my_tty(m->session);
+        m->managed = m->my_tty && geteuid() > 0;
+
+        m->r = rand() % 0xff;
+        m->g = rand() % 0xff;
+        m->b = rand() % 0xff;
+        m->r_up = m->g_up = m->b_up = true;
+
+        r = sd_event_default(&m->event);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_open_system(&m->bus);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_attach_event(m->bus, m->event, SD_EVENT_PRIORITY_NORMAL);
+        if (r < 0)
+                return r;
+
+        r = sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
+        if (r < 0)
+                return r;
+
+        r = sd_event_add_exit(m->event, &m->exit_src, modeset_exit_fn, m);
+        if (r < 0)
+                return r;
+
+        /* schedule before sd-bus close */
+        r = sd_event_source_set_priority(m->exit_src, -10);
+        if (r < 0)
+                return r;
+
+        r = sysview_context_new(&m->sysview,
+                                SYSVIEW_CONTEXT_SCAN_LOGIND |
+                                SYSVIEW_CONTEXT_SCAN_DRM,
+                                m->event,
+                                m->bus,
+                                NULL);
+        if (r < 0)
+                return r;
+
+        r = grdev_context_new(&m->grdev, m->event, m->bus);
+        if (r < 0)
+                return r;
+
+        *out = m;
+        m = NULL;
+        return 0;
+}
+
+static uint8_t next_color(bool *up, uint8_t cur, unsigned int mod) {
+        uint8_t next;
+
+        /* generate smoothly morphing colors */
+
+        next = cur + (*up ? 1 : -1) * (rand() % mod);
+        if ((*up && next < cur) || (!*up && next > cur)) {
+                *up = !*up;
+                next = cur;
+        }
+
+        return next;
+}
+
+static void modeset_draw(Modeset *m, const grdev_display_target *t) {
+        uint32_t j, k, *b;
+        uint8_t *l;
+
+        assert(t->fb->format == DRM_FORMAT_XRGB8888 || t->fb->format == DRM_FORMAT_ARGB8888);
+        assert(!t->rotate);
+        assert(!t->flip);
+
+        l = t->fb->maps[0];
+        for (j = 0; j < t->height; ++j) {
+                for (k = 0; k < t->width; ++k) {
+                        b = (uint32_t*)l;
+                        b[k] = (0xff << 24) | (m->r << 16) | (m->g << 8) | m->b;
+                }
+
+                l += t->fb->strides[0];
+        }
+}
+
+static void modeset_render(Modeset *m, grdev_display *d) {
+        const grdev_display_target *t;
+
+        m->r = next_color(&m->r_up, m->r, 20);
+        m->g = next_color(&m->g_up, m->g, 10);
+        m->b = next_color(&m->b_up, m->b, 5);
+
+        GRDEV_DISPLAY_FOREACH_TARGET(d, t, 0) {
+                modeset_draw(m, t);
+                grdev_display_flip_target(d, t, 1);
+        }
+
+        grdev_session_commit(m->grdev_session);
+}
+
+static void modeset_grdev_fn(grdev_session *session, void *userdata, grdev_event *ev) {
+        Modeset *m = userdata;
+
+        switch (ev->type) {
+        case GRDEV_EVENT_DISPLAY_ADD:
+                grdev_display_enable(ev->display_add.display);
+                modeset_render(m, ev->display_add.display);
+                break;
+        case GRDEV_EVENT_DISPLAY_REMOVE:
+                break;
+        case GRDEV_EVENT_DISPLAY_CHANGE:
+                modeset_render(m, ev->display_change.display);
+                break;
+        case GRDEV_EVENT_DISPLAY_FRAME:
+                modeset_render(m, ev->display_frame.display);
+                break;
+        }
+}
+
+static int modeset_sysview_fn(sysview_context *c, void *userdata, sysview_event *ev) {
+        unsigned int flags, type;
+        Modeset *m = userdata;
+        sysview_device *d;
+        const char *name;
+        int r;
+
+        switch (ev->type) {
+        case SYSVIEW_EVENT_SESSION_FILTER:
+                if (streq_ptr(m->session, ev->session_filter.id))
+                        return 1;
+
+                break;
+        case SYSVIEW_EVENT_SESSION_ADD:
+                assert(!m->grdev_session);
+
+                name = sysview_session_get_name(ev->session_add.session);
+                flags = 0;
+
+                if (m->managed)
+                        flags |= GRDEV_SESSION_MANAGED;
+
+                r = grdev_session_new(&m->grdev_session,
+                                      m->grdev,
+                                      flags,
+                                      name,
+                                      modeset_grdev_fn,
+                                      m);
+                if (r < 0) {
+                        log_error("Cannot create grdev session: %s", strerror(-r));
+                        return r;
+                }
+
+                if (m->managed) {
+                        r = sysview_session_take_control(ev->session_add.session);
+                        if (r < 0) {
+                                log_error("Cannot request session control: %s", strerror(-r));
+                                return r;
+                        }
+                }
+
+                grdev_session_enable(m->grdev_session);
+
+                break;
+        case SYSVIEW_EVENT_SESSION_REMOVE:
+                if (!m->grdev_session)
+                        return 0;
+
+                grdev_session_restore(m->grdev_session);
+                grdev_session_disable(m->grdev_session);
+                m->grdev_session = grdev_session_free(m->grdev_session);
+                sd_event_exit(m->event, 0);
+                break;
+        case SYSVIEW_EVENT_SESSION_ATTACH:
+                d = ev->session_attach.device;
+                type = sysview_device_get_type(d);
+                if (type == SYSVIEW_DEVICE_DRM)
+                        grdev_session_add_drm(m->grdev_session, sysview_device_get_ud(d));
+
+                break;
+        case SYSVIEW_EVENT_SESSION_DETACH:
+                d = ev->session_detach.device;
+                type = sysview_device_get_type(d);
+                if (type == SYSVIEW_DEVICE_DRM)
+                        grdev_session_remove_drm(m->grdev_session, sysview_device_get_ud(d));
+
+                break;
+        case SYSVIEW_EVENT_SESSION_CONTROL:
+                r = ev->session_control.error;
+                if (r < 0) {
+                        log_error("Cannot acquire session control: %s", strerror(-r));
+                        return r;
+                }
+
+                r = ioctl(1, KDSKBMODE, K_UNICODE);
+                if (r < 0) {
+                        log_error("Cannot set K_UNICODE on stdout: %m");
+                        return -errno;
+                }
+
+                break;
+        }
+
+        return 0;
+}
+
+static int modeset_run(Modeset *m) {
+        struct termios in_attr, saved_attr;
+        int r;
+
+        assert(m);
+
+        if (!m->my_tty) {
+                log_warning("You need to run this program on a free VT");
+                return -EACCES;
+        }
+
+        if (!m->managed && geteuid() > 0)
+                log_warning("You run in unmanaged mode without being root. This is likely to fail..");
+
+        printf("modeset - Show test pattern on selected graphics devices\n"
+               "          Running on seat '%s' in user-session '%s'\n"
+               "          Exit by pressing ^C\n\n",
+               m->seat ? : "seat0", m->session ? : "<none>");
+
+        r = sysview_context_start(m->sysview, modeset_sysview_fn, m);
+        if (r < 0)
+                goto out;
+
+        r = tcgetattr(0, &in_attr);
+        if (r < 0) {
+                r = -errno;
+                goto out;
+        }
+
+        saved_attr = in_attr;
+        in_attr.c_lflag &= ~ECHO;
+
+        r = tcsetattr(0, TCSANOW, &in_attr);
+        if (r < 0) {
+                r = -errno;
+                goto out;
+        }
+
+        r = sd_event_loop(m->event);
+        tcsetattr(0, TCSANOW, &saved_attr);
+        printf("exiting..\n");
+
+out:
+        sysview_context_stop(m->sysview);
+        return r;
+}
+
+static int help(void) {
+        printf("%s [OPTIONS...]\n\n"
+               "Show test pattern on all selected graphics devices.\n\n"
+               "  -h --help               Show this help\n"
+               "     --version            Show package version\n"
+               , program_invocation_short_name);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+        enum {
+                ARG_VERSION = 0x100,
+        };
+        static const struct option options[] = {
+                { "help",       no_argument,    NULL, 'h'               },
+                { "version",    no_argument,    NULL, ARG_VERSION       },
+                {},
+        };
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
+                switch (c) {
+                case 'h':
+                        help();
+                        return 0;
+
+                case ARG_VERSION:
+                        puts(PACKAGE_STRING);
+                        puts(SYSTEMD_FEATURES);
+                        return 0;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+
+        if (argc > optind) {
+                log_error("Too many arguments");
+                return -EINVAL;
+        }
+
+        return 1;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(modeset_freep) Modeset *m = NULL;
+        int r;
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        srand(time(NULL));
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                goto finish;
+
+        r = modeset_new(&m);
+        if (r < 0)
+                goto finish;
+
+        r = modeset_run(m);
+
+finish:
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}