zdev: Add build option to update initial RAM-disk by default

Some Linux distributions always include a copy of all persistent device
configuration data when updating the initial RAM-disk. This makes
chzdev's persistent device configuration changes ineffective because
device configuration directives applied in the RAM-disk take precedence
over those stored in the root filesystem.

This patch introduces a new build-time switch which allows distributions
to specify that whenever there is a persistent device configuration
change, the RAM-disk is updated automatically.

This feature can be enabled by adding 'ZDEV_ALWAYS_UPDATE_INITRD=1' as
a zdev build option. Where, by default ZDEV_ALWAYS_UPDATE_INITRD is 0.

Co-developed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

README.md

@@ -284,10 +284,11 @@ build options:
 
 This table lists additional build or install options:
 
-| __COMPONENT__  | __OPTION__       | __TOOLS__                       |
-|----------------|:----------------:|:-------------------------------:|
-| dracut         | `HAVE_DRACUT`    | zdev                            |
-| initramfs-tools| `HAVE_INITRAMFS` | zdev                            |
+| __COMPONENT__    | __OPTION__                   | __TOOLS__      |
+|------------------|:----------------------------:|:--------------:|
+| dracut           | `HAVE_DRACUT`                | zdev           |
+| initramfs-tools  | `HAVE_INITRAMFS`             | zdev           |
+|                  | `ZDEV_ALWAYS_UPDATE_INITRD`  | zdev           |
 
 The s390-tools build process uses "pkg-config" if available and hard-coded
 compiler and linker options otherwise.
@@ -378,6 +379,17 @@ the different tools are provided:
   Distributors with different boot or RAM-disk mechanisms should provide
   a custom zdev-root-update helper script.
 
+  - `ZDEV_ALWAYS_UPDATE_INITRD=1` upon modification of any persistent device
+    configuration, chzdev updates the initial RAM-disk by default, without any
+    additional user interaction.
+
+  For some distributions, all the configuration attributes must be copied to
+  the initial RAM-disk. Because the device configuration directives applied
+  in the initial RAM-disk takes precedence over those stored in the root file-
+  system. This copying is done usually by explicitly invoking a command. This
+  build option makes it user-friendly and does this copying without any manual
+  intervention.
+
   Some functions of zdev require that the following programs are available:
 
   - modprobe (kmod)

zdev/include/root.h

@@ -12,6 +12,6 @@
 
 #include "exit_code.h"
 
-exit_code_t root_check(void);
+exit_code_t initrd_check(bool all_pers);
 
 #endif /* ROOT_H */

zdev/src/Makefile

@@ -4,6 +4,16 @@ include ../../common.mak
 ALL_CPPFLAGS += -I ../include -std=gnu99 -Wno-unused-parameter \
 	-Wno-missing-field-initializers
 
+# Adding ZDEV_ALWAYS_UPDATE_INITRD=1 option will update the initial RAM-disk
+# without the user interaction upon the modification of a persistent device
+# configuration.
+
+ifeq ($(ZDEV_ALWAYS_UPDATE_INITRD),1)
+ALL_CPPFLAGS += -DZDEV_ALWAYS_UPDATE_INITRD=true
+else
+ALL_CPPFLAGS += -DZDEV_ALWAYS_UPDATE_INITRD=false
+endif
+
 # Core
 chzdev_objects += attrib.o chzdev.o device.o devnode.o devtype.o exit_code.o \
 		  export.o hash.o inuse.o misc.o namespace.o opts.o path.o \

zdev/src/chzdev.c

@@ -3027,7 +3027,7 @@ int main(int argc, char *argv[])
 	    !dryrun) {
 		/* If the root device/device type or early devices have been
 		 * modified, additional work might be necessary. */
-		rc = root_check();
+		rc = initrd_check(ZDEV_ALWAYS_UPDATE_INITRD);
 		if (rc && !drc)
 			drc = rc;
 	}

zdev/src/root.c

@@ -58,11 +58,50 @@ static void add_early_removed(struct util_list *selected)
 	}
 }
 
+static void add_pers_removed(struct util_list *strlist)
+{
+	int i, j;
+	struct devtype *dt;
+	struct subtype *st;
+	struct device *dev;
+
+	for (i = 0; devtypes[i]; i++) {
+		dt = devtypes[i];
+		for (j = 0; dt->subtypes[j]; j++) {
+			st = dt->subtypes[j];
+			util_list_iterate(&st->devices->hash.list, dev) {
+				if (dev->persistent.deconfigured) {
+					strlist_add(strlist, "%s %s",
+						    dev->subtype->devname, dev->id);
+				}
+			}
+		}
+	}
+}
+
+static bool is_zdev_early_0(struct selected_dev_node *sel)
+{
+	struct setting *s;
+	struct device *dev;
+
+	dev = device_list_find(sel->st->devices, sel->id, NULL);
+	if (!dev)
+		return false;
+	s = setting_list_find(dev->persistent.settings,
+			      internal_attr_early.name);
+	if (!s)
+		return false;
+	if (s->specified && strcmp(s->value, "0") == 0)
+		return true;
+
+	return false;
+}
+
 /* Determine if initial RAM-disk needs updating. If so, run the corresponding
  * scripts if available. */
-exit_code_t root_check(void)
+exit_code_t initrd_check(bool all_pers)
 {
-	struct util_list *selected, *params, *mod = NULL;
+	struct util_list *selected, *params, *mod = strlist_new();
 	struct selected_dev_node *sel;
 	struct device *dev;
 	char *params_str;
@@ -76,6 +115,20 @@ exit_code_t root_check(void)
 	/* Get list of devices that provide the root device or require
 	 * early configuration. */
 	selected = selected_dev_list_new();
+
+	if (all_pers) {
+		/* Add all persistently configured devices. */
+		select = select_opts_new();
+		select->configured = 1;
+		select_devices(select, selected, 1, 0, 0, config_persistent,
+			       scope_mandatory, err_ignore);
+		select_opts_free(select);
+
+		/* Ensure that removed devices are considered. */
+		add_pers_removed(mod);
+		goto check_mod;
+	}
+
 	/* First add devices that had zdev:early removed or changed to 0.
 	 * The subsequent call to select_devices() will filter out any
 	 * duplicates. */
@@ -95,8 +148,8 @@ exit_code_t root_check(void)
 		       err_ignore);
 	select_opts_free(select);
 
+check_mod:
 	/* Determine if any of the devices or device types has been modified. */
-	mod = strlist_new();
 	util_list_iterate(selected, sel) {
 		dt = sel->st->devtype;
 
@@ -127,17 +180,22 @@ exit_code_t root_check(void)
 		goto out;
 	}
 
-	/* Ask for confirmation. */
-	if (!confirm("Update initial RAM-disk now?")) {
-		rc = EXIT_ABORTED;
-		goto out;
+	if (!all_pers) {
+		/* Ask for confirmation. */
+		if (!confirm("Update initial RAM-disk now?")) {
+			rc = EXIT_ABORTED;
+			goto out;
+		}
 	}
 
 	/* Build the command line. */
 	params = strlist_new();
 	util_list_iterate(selected, sel) {
-		strlist_add(params, "%s", sel->st->name);
-		strlist_add(params, "%s", sel->id);
+		/* From the selected list, remove the devices with zdev:early=0 */
+		if (!is_zdev_early_0(sel)) {
+			strlist_add(params, "%s", sel->st->name);
+			strlist_add(params, "%s", sel->id);
+		}
 	}
 	params_str = strlist_flatten(params, " ");
 	strlist_free(params);