zdev: Implement internal device attributes

This change adds base infrastructure for implementing internal device
attributes. In the context of the zdev tools, an internal device
attribute is a new type of device attribute with the following
characteristics:

  - Can be set and removed like normal device attributes
  - Affects zdev-internal handling only
  - Does not correspond to an actual device attribute, that is
    it has no representation in SysFS
  - Can not be set in the active configuration
  - Name starts with "zdev:" to prevent conflicts with actual
    device attributes

Values for internal device attributes are stored in udev rules alongside
the normal persistent configuration of a device. They are encoded as
udev environment variables. Note that they have no further effect on
udev processing.

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zdev/src/Makefile

@@ -8,7 +8,7 @@ ALL_CPPFLAGS += -I ../include -std=gnu99 -Wno-unused-parameter \
 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 \
 		  root.o select.o setting.o subtype.o table.o table_attribs.o \
-		  table_types.o net.o firmware.o
+		  table_types.o net.o firmware.o internal.o
 
 # Devtype Helpers
 chzdev_objects += blkinfo.o ccw.o ccwgroup.o findmnt.o modprobe.o module.o \
@@ -38,7 +38,7 @@ chzdev_objects += generic_ccw.o
 lszdev_objects += attrib.o lszdev.o device.o devnode.o devtype.o exit_code.o \
 		  export.o hash.o inuse.o misc.o namespace.o opts.o path.o \
 		  root.o select.o setting.o subtype.o table.o table_types.o \
-		  net.o
+		  net.o internal.o
 
 # Devtype Helpers
 lszdev_objects += blkinfo.o ccw.o ccwgroup.o findmnt.o modprobe.o module.o \

zdev/src/device.c

@@ -16,6 +16,7 @@
 #include "attrib.h"
 #include "device.h"
 #include "devtype.h"
+#include "internal.h"
 #include "misc.h"
 #include "namespace.h"
 #include "setting.h"
@@ -221,6 +222,9 @@ static exit_code_t apply_setting(struct device *dev, config_t config,
 			goto err_activeonly_forceable;
 		if (!force && SCOPE_AUTOCONF(config) && a->activeonly)
 			goto err_activeonly_forceable;
+		/* Check for internal. */
+		if (config == config_active && a->internal)
+			goto err_int_noactive;
 		/* Check for multiple values. */
 		if (!force && !a->multi && strlist_find(processed, key))
 			goto err_multi_forceable;
@@ -230,6 +234,9 @@ static exit_code_t apply_setting(struct device *dev, config_t config,
 			goto err_unknown;
 		if (!force)
 			goto err_unknown_forceable;
+		/* Check for internal. */
+		if (config == config_active && internal_by_name(key))
+			goto err_int_noactive;
 	}
 
 	strlist_add(processed, "%s", key);
@@ -294,6 +301,11 @@ err_activeonly_forceable:
 	delayed_forceable("Attribute '%s' should only be changed in the active "
 			  "config\n", a->name);
 	return EXIT_INVALID_SETTING;
+
+err_int_noactive:
+	delayed_err("Internal attribute '%s' cannot be set in the active config\n",
+		    key);
+	return EXIT_INVALID_SETTING;
 }
 
 /* Apply device settings from strlist to device. */
@@ -542,6 +554,9 @@ exit_code_t device_write_active_settings(struct device *dev)
 		s = p->ptr;
 		if (!s->modified || s->removed)
 			continue;
+		if ((s->attrib && s->attrib->internal) ||
+		    internal_by_name(s->name))
+			continue;
 
 		path = subtype_get_active_attrib_path(st, dev, s->name);
 		if (!path) {

zdev/src/internal.c

@@ -0,0 +1,25 @@
+/*
+ * zdev - Modify and display the persistent configuration of devices
+ *
+ * Copyright IBM Corp. 2017
+ *
+ * s390-tools is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ */
+
+#include <stdbool.h>
+
+#include "internal.h"
+#include "misc.h"
+
+/* Return identifier of internal attribute with specified @name. */
+const char *internal_get_name(const char *name)
+{
+	return name + sizeof(INTERNAL_ATTR_PREFIX) - 1;
+}
+
+/* Check if attribute is internal by name. */
+bool internal_by_name(const char *name)
+{
+	return starts_with(name, INTERNAL_ATTR_PREFIX);
+}

zdev/src/misc.c

@@ -1717,3 +1717,18 @@ void debug_init(int argc, char *argv[])
 		fprintf(stderr, "%s\"%s\"", i > 0 ? ", " : "", argv[i]);
 	fprintf(stderr, "\n");
 }
+
+/* Return the last occurrence of @needle in @haystack, or %NULL if @needle
+ * was not found. */
+char *misc_strrstr(const char *haystack, const char *needle)
+{
+	char *result, *next;
+
+	result = strstr(haystack, needle);
+	if (result) {
+		while ((next = strstr(result + 1, needle)))
+			result = next;
+	}
+
+	return result;
+}

zdev/src/udev.c

@@ -409,3 +409,35 @@ void udev_settle(void)
 		return;
 	misc_system(err_ignore, "%s settle", PATH_UDEVADM);
 }
+
+/* Extract internal attribute settings from @entry and add to @list.
+ * Associate corresponding attribute if found in @attribs. */
+void udev_add_internal_from_entry(struct setting_list *list,
+				  struct udev_entry_node *entry,
+				  struct attrib **attribs)
+{
+	char *copy, *name, *end, *u;
+	struct attrib *a;
+
+	/* ENV{zdev_var}="1" */
+	copy = misc_strdup(entry->key);
+
+	/* Find attribute name start. */
+	name = strchr(copy, '{');
+	end = strrchr(copy, '}');
+	if (!name || !end)
+		goto out;
+	*end = 0;
+	name++;
+
+	/* zdev_ => zdev: */
+	u = strchr(name, '_');
+	if (u)
+		*u = ':';
+
+	a = attrib_find(attribs, name);
+	setting_list_apply_actual(list, a, name, entry->value);
+
+out:
+	free(copy);
+}

zdev/src/udev_ccw.c

@@ -18,6 +18,7 @@
 #include "attrib.h"
 #include "ccw.h"
 #include "device.h"
+#include "internal.h"
 #include "misc.h"
 #include "path.h"
 #include "setting.h"
@@ -49,6 +50,12 @@ static void add_setting_from_entry(struct setting_list *list,
 	char *copy, *name, *end;
 	struct attrib *a;
 
+	/* ENV{zdev_var}="1" */
+	if (starts_with(entry->key, "ENV{zdev_") &&
+	    strcmp(entry->op, "=") == 0) {
+		udev_add_internal_from_entry(list, entry, attribs);
+		return;
+	}
 	/* ATTR{[ccw/0.0.37bf]online}=1 */
 	if (strncmp(entry->key, "ATTR{[ccw/", 10) != 0 ||
 	    strcmp(entry->op, "=") != 0)
@@ -190,7 +197,14 @@ exit_code_t udev_ccw_write_device(struct device *dev, bool autoconf)
 		s = p->ptr;
 		if (s->removed)
 			continue;
-		fprintf(fd, "ATTR{[ccw/%s]%s}=\"%s\"\n", id, s->name, s->value);
+		if ((s->attrib && s->attrib->internal) ||
+		    internal_by_name(s->name)) {
+			fprintf(fd, "ENV{zdev_%s}=\"%s\"\n",
+				internal_get_name(s->name), s->value);
+		} else {
+			fprintf(fd, "ATTR{[ccw/%s]%s}=\"%s\"\n", id, s->name,
+				s->value);
+		}
 	}
 
 	/* Write udev rule epilog. */

zdev/src/udev_ccwgroup.c

@@ -18,6 +18,7 @@
 #include "attrib.h"
 #include "ccwgroup.h"
 #include "device.h"
+#include "internal.h"
 #include "misc.h"
 #include "path.h"
 #include "setting.h"
@@ -68,6 +69,12 @@ static void add_setting_from_entry(struct setting_list *list,
 	char *copy, *name, *end;
 	struct attrib *a;
 
+	/* ENV{zdev_var}="1" */
+	if (starts_with(entry->key, "ENV{zdev_") &&
+	    strcmp(entry->op, "=") == 0) {
+		udev_add_internal_from_entry(list, entry, attribs);
+		return;
+	}
 	/* ATTR{[ccwgroup/0.0.f5f0]online}=1 */
 	if (strncmp(entry->key, "ATTR{[ccwgroup/", 10) != 0 ||
 	    strcmp(entry->op, "=") != 0)
@@ -282,6 +289,10 @@ exit_code_t udev_ccwgroup_write_device(struct device *dev, bool autoconf)
 				fprintf(fd, "ATTR{[ccwgroup/%s]%s}=\"%s\"\n",
 					ccw_id, s->name, str->str);
 			}
+		} else if ((s->attrib && s->attrib->internal) ||
+			   internal_by_name(s->name)) {
+			fprintf(fd, "ENV{zdev_%s}=\"%s\"\n",
+				internal_get_name(s->name), s->value);
 		} else {
 			fprintf(fd, "ATTR{[ccwgroup/%s]%s}=\"%s\"\n", ccw_id,
 				s->name, s->value);

zdev/src/udev_zfcp_lun.c

@@ -18,6 +18,7 @@
 
 #include "attrib.h"
 #include "device.h"
+#include "internal.h"
 #include "misc.h"
 #include "path.h"
 #include "scsi.h"
@@ -128,7 +129,7 @@ static bool zfcp_lun_devid_from_entry(struct zfcp_lun_devid *id_ptr,
 				      struct udev_entry_node *entry)
 {
 	struct zfcp_lun_devid id;
-	char *copy = NULL, *s;
+	char *copy = NULL, *s, *e, *u;
 	int i;
 	bool rc = false;
 
@@ -182,6 +183,28 @@ static bool zfcp_lun_devid_from_entry(struct zfcp_lun_devid *id_ptr,
 		goto out;
 	}
 
+	/*ENV{zdev_var__0_0_1941_0x500507630510c1ae_0x402340d400000000}="1"*/
+	if (starts_with(entry->key, "ENV{zdev_")) {
+		copy = misc_strdup(entry->key);
+
+		/* Find ID start (last __) and end (last }). */
+		s = misc_strrstr(copy, "__");
+		e = strrchr(copy, '}');
+		if (!s || !e)
+			goto out;
+		*e = 0;
+		s += 2;
+		/* Convert variable name to ID format. */
+		for (i = 0, u = s; (u = strchr(u, '_')); i++, u++) {
+			if (i < 2)
+				*u = '.';
+			else
+				*u = ':';
+		}
+		rc = zfcp_lun_parse_devid(&id, s, err_ignore) == EXIT_OK ?
+			true : false;
+	}
+
 out:
 	free(copy);
 	if (rc)
@@ -211,11 +234,46 @@ static struct zfcp_lun_node *zfcp_lun_node_from_entry(
 	return node;
 }
 
+static void add_internal_setting_from_entry(struct udev_entry_node *entry,
+					    struct zfcp_lun_node *node)
+{
+	char *copy, *name, *end, *u;
+	struct attrib *a;
+
+	/*ENV{zdev_var__0_0_1941_0x500507630510c1ae_0x402340d400000000}="1"*/
+	copy = misc_strdup(entry->key);
+
+	/* Find attribute name start and end. */
+	name = strchr(copy, '{');
+	end = misc_strrstr(copy, "__");
+	if (!name || !end)
+		goto out;
+	*end = 0;
+	name++;
+
+	/* zdev_ => zdev: */
+	u = strchr(name, '_');
+	if (u)
+		*u = ':';
+
+	a = attrib_find(zfcp_lun_subtype.dev_attribs, name);
+	setting_list_apply_actual(node->fc_settings, a, name, entry->value);
+
+out:
+	free(copy);
+}
+
 static void add_fc_setting_from_entry(struct udev_entry_node *entry,
 				      struct zfcp_lun_node *node)
 {
 	char *copy, *s, *e;
 
+	/*ENV{zdev_var__0_0_1941_0x500507630510c1ae_0x402340d400000000}="1"*/
+	if (starts_with(entry->key, "ENV{zdev_") &&
+	    strcmp(entry->op, "=") == 0) {
+		add_internal_setting_from_entry(entry, node);
+		return;
+	}
 	/*ATTR{[ccw/0.0.1941]0x500507630510c1ae/0x402340d400000000/failed}="0"*/
 	if (!starts_with(entry->key, "ATTR{[ccw/"))
 		return;
@@ -490,7 +548,7 @@ static struct zfcp_lun_node *state_to_zfcp_lun_node(struct zfcp_lun_devid *id,
 					s->value);
 			setting_list_add(node->scsi_settings, n);
 		} else {
-			n = setting_new(NULL, s->name, s->value);
+			n = setting_new(s->attrib, s->name, s->value);
 			setting_list_add(node->fc_settings, n);
 		}
 	}
@@ -580,9 +638,21 @@ static exit_code_t write_luns_rule(const char *path, struct util_list *list)
 			node->id.lun);
 
 		util_list_iterate(&node->fc_settings->list, s) {
-			fprintf(fd, "ATTR{[ccw/%s]0x%016" PRIx64 "/0x%016"
-				PRIx64 "/%s}=\"%s\"\n", hba_id, node->id.wwpn,
-				node->id.lun, s->name, s->value);
+			if ((s->attrib && s->attrib->internal) ||
+			    internal_by_name(s->name)) {
+				fprintf(fd, "ENV{zdev_%s__%x_%x_%04x_0x%016"
+					PRIx64 "_0x%016" PRIx64 "}=\"%s\"\n",
+					internal_get_name(s->name),
+					node->id.fcp_dev.cssid,
+					node->id.fcp_dev.ssid,
+					node->id.fcp_dev.devno, node->id.wwpn,
+					node->id.lun, s->value);
+			} else {
+				fprintf(fd, "ATTR{[ccw/%s]0x%016" PRIx64
+					"/0x%016" PRIx64 "/%s}=\"%s\"\n",
+					hba_id, node->id.wwpn, node->id.lun,
+					s->name, s->value);
+			}
 		}
 		last_node = node;
 	}