Merge branch 'devttynullsplash' into 'main'

main: Assume graphical splash when the active kernel console is /dev/ttynull.

See merge request plymouth/plymouth!327

src/libply-splash-core/ply-device-manager.c

@@ -974,7 +974,9 @@ add_consoles_from_file (ply_device_manager_t *manager,
         contents_length = read (fd, contents, sizeof(contents) - 1);
 
         if (contents_length <= 0) {
-                ply_trace ("couldn't read it: %m");
+                if (contents_length < 0)
+                        ply_trace ("couldn't read it: %m");
+
                 close (fd);
                 return false;
         }

src/libply/ply-utils.c

@@ -1259,6 +1259,34 @@ ply_kernel_command_line_override (const char *command_line)
         kernel_command_line_is_set = true;
 }
 
+char *
+ply_get_primary_kernel_console_type (void)
+{
+        int fd;
+        int len;
+        char proc_consoles[4096] = "";
+        size_t return_length;
+
+        if (ply_file_exists ("/proc/consoles")) {
+                ply_trace ("opening /proc/consoles");
+
+                fd = open ("/proc/consoles", O_RDONLY);
+                len = read (fd, proc_consoles, sizeof(proc_consoles));
+                close (fd);
+
+                /* The device type for /dev/ttyS0 is "ttyS".
+                 * for /dev/ttynull it is "ttynull", which appears as "ttynull0" in /proc/consoles. Exclude any numbers at the end.
+                 */
+                for (return_length = 0; return_length < len; return_length++) {
+                        /* Read until the next digit or space, the digit should be first */
+                        if (isdigit (proc_consoles[return_length]) || isspace (proc_consoles[return_length]))
+                                return strndup (proc_consoles, return_length);
+                }
+        }
+
+        return NULL;
+}
+
 double ply_strtod (const char *str)
 {
         char *old_locale;

src/libply/ply-utils.h

@@ -176,6 +176,8 @@ bool ply_kernel_command_line_has_argument (const char *argument);
 void ply_kernel_command_line_override (const char *command_line);
 char *ply_kernel_command_line_get_key_value (const char *key);
 
+char *ply_get_primary_kernel_console_type (void);
+
 double ply_strtod (const char *str);
 
 bool ply_is_secure_boot_enabled (void);

src/main.c

@@ -884,6 +884,19 @@ sh_is_init (state_t *state)
         return result;
 }
 
+static bool
+kernel_console_is_ttynull (void)
+{
+        char *kernel_console = ply_get_primary_kernel_console_type ();
+
+        /* If the primary console is ttynull, the kernel console is virtual.
+         */
+        if (strcmp (kernel_console, "ttynull") == 0)
+                return true;
+
+        return false;
+}
+
 static bool
 plymouth_should_show_default_splash (state_t *state)
 {
@@ -925,7 +938,7 @@ plymouth_should_show_default_splash (state_t *state)
         }
 
         if (state->should_force_default_splash) {
-                ply_trace ("using default splash because kernel command line has option \"plymouth.graphical\"");
+                ply_trace ("using default splash because forced by \"plymouth.graphical\" or no active kernel console");
                 return true;
         }
 
@@ -2457,7 +2470,7 @@ main (int    argc,
         signal (SIGSEGV, on_crash);
         signal (SIGFPE, on_crash);
 
-        if (graphical_boot || ply_kernel_command_line_has_argument ("plymouth.graphical")) {
+        if (graphical_boot || ply_kernel_command_line_has_argument ("plymouth.graphical") || kernel_console_is_ttynull ()) {
                 state.should_force_default_splash = true;
                 ignore_serial_consoles = true;
         }