udevd: at startup create /dev/null, /dev/console, /dev/kmsg

udev/lib/libudev-ctrl.c

@@ -22,7 +22,7 @@
 #include "libudev.h"
 #include "libudev-private.h"
 
-/* last known version with this wire protocol */
+/* wire protocol magic must match */
 #define UDEV_CTRL_MAGIC				0xdead1dea
 
 enum udev_ctrl_msg_type {

udev/udev-node.c

@@ -68,7 +68,7 @@ static int name_index(struct udev *udev, const char *devpath, const char *name,
 int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mode_t mode, uid_t uid, gid_t gid)
 {
 	struct udev *udev = udev_device_get_udev(dev);
-	char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
+	char filename[UTIL_PATH_SIZE];
 	struct stat stats;
 	int preserve = 0;
 	int err = 0;
@@ -81,8 +81,14 @@ int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mod
 	else
 		mode |= S_IFCHR;
 
-	if (file == NULL)
+	if (file == NULL) {
 		file = udev_device_get_devnode(dev);
+	} else if (file[0] != '/') {
+		util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
+		util_strlcat(filename, "/", sizeof(filename));
+		util_strlcat(filename, file, sizeof(filename));
+		file = filename;
+	}
 
 	if (lstat(file, &stats) == 0) {
 		if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {
@@ -90,6 +96,8 @@ int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mod
 			preserve = 1;
 			udev_selinux_lsetfilecon(udev, file, mode);
 		} else {
+			char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
+
 			info(udev, "atomically replace existing file '%s'\n", file);
 			util_strlcpy(file_tmp, file, sizeof(file_tmp));
 			util_strlcat(file_tmp, TMP_FILE_EXT, sizeof(file_tmp));

udev/udevd.c

@@ -708,6 +708,28 @@ static void export_initial_seqnum(struct udev *udev)
 	}
 }
 
+/* create the nodes the we depend on to properly start up */
+static void setup_initial_nodes(struct udev *udev)
+{
+	struct udev_device *dev;
+
+	dev = udev_device_new_from_subsystem_sysname(udev, "mem", "null");
+	if (dev != NULL) {
+		udev_node_mknod(dev, "null", makedev(0,0), 0666, 0, 0);
+		udev_device_unref(dev);
+	}
+	dev = udev_device_new_from_subsystem_sysname(udev, "mem", "kmsg");
+	if (dev != NULL) {
+		udev_node_mknod(dev, "kmsg", makedev(0,0), 0660, 0, 0);
+		udev_device_unref(dev);
+	}
+	dev = udev_device_new_from_subsystem_sysname(udev, "tty", "console");
+	if (dev != NULL) {
+		udev_node_mknod(dev, "console", makedev(0,0), 0600, 0, 0);
+		udev_device_unref(dev);
+	}
+}
+
 static void startup_log(struct udev *udev)
 {
 	FILE *f;
@@ -814,6 +836,8 @@ int main(int argc, char *argv[])
 		goto exit;
 	}
 
+	setup_initial_nodes(udev);
+
 	/* make sure std{in,out,err} fd's are in a sane state */
 	fd = open("/dev/null", O_RDWR);
 	if (fd < 0) {