From be88b819ecec075187ac313b8ab15d8ed8004b54 Mon Sep 17 00:00:00 2001
From: Jan Synacek <jsynacek@redhat.com>
Date: Wed, 11 Sep 2019 12:35:18 +0200
Subject: [PATCH] udev: introduce CONST key name
Currently, there is no way to match against system-wide constants, such
as architecture or virtualization type, without forking helper binaries.
That potentially results in a huge number of spawned processes which
output always the same answer.
This patch introduces a special CONST keyword which takes a hard-coded
string as its key and returns a value assigned to that key. Currently
implemented are CONST{arch} and CONST{virt}, which can be used to match
against the system's architecture and virtualization type.
(based on commit 4801d8afe2ff1c1c075c9f0bc5631612172e0bb7)
Resolves: #1748051
---
man/udev.xml | 26 ++++++++++++++++++++++++++
rules/40-redhat.rules | 4 ++--
src/udev/udev-rules.c | 39 +++++++++++++++++++++++++++++++++++++++
test/rule-syntax-check.py | 2 +-
4 files changed, 68 insertions(+), 3 deletions(-)
diff --git a/man/udev.xml b/man/udev.xml
index a948ea79a9..fc02edd214 100644
--- a/man/udev.xml
+++ b/man/udev.xml
@@ -240,6 +240,32 @@
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>CONST{<replaceable>key</replaceable>}</varname></term>
+ <listitem>
+ <para>Match against a system-wide constant. Supported keys are:</para>
+ <variablelist>
+ <varlistentry>
+ <term><literal>arch</literal></term>
+ <listitem>
+ <para>System's architecture. See <option>ConditionArchitecture=</option> in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for possible values.</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>virt</literal></term>
+ <listitem>
+ <para>System's virtualization environment. See
+ <citerefentry><refentrytitle>systemd-detect-virt</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ for possible values.</para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <para>Unknown keys will never match.</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>TAG</varname></term>
<listitem>
diff --git a/rules/40-redhat.rules b/rules/40-redhat.rules
index 2c690e522e..83d823e172 100644
--- a/rules/40-redhat.rules
+++ b/rules/40-redhat.rules
@@ -6,10 +6,10 @@ SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}
# Memory hotadd request
SUBSYSTEM!="memory", GOTO="memory_hotplug_end"
ACTION!="add", GOTO="memory_hotplug_end"
-PROGRAM="/bin/uname -p", RESULT=="s390*", GOTO="memory_hotplug_end"
+CONST{arch}=="s390*", GOTO="memory_hotplug_end"
ENV{.state}="online"
-PROGRAM="/bin/systemd-detect-virt", RESULT=="none", ENV{.state}="online_movable"
+CONST{virt}=="none", ENV{.state}="online_movable"
ATTR{state}=="offline", ATTR{state}="$env{.state}"
LABEL="memory_hotplug_end"
diff --git a/src/udev/udev-rules.c b/src/udev/udev-rules.c
index c9a0197534..9211f563b1 100644
--- a/src/udev/udev-rules.c
+++ b/src/udev/udev-rules.c
@@ -29,12 +29,14 @@
#include <fnmatch.h>
#include <time.h>
+#include "architecture.h"
#include "udev.h"
#include "path-util.h"
#include "conf-files.h"
#include "strbuf.h"
#include "strv.h"
#include "util.h"
+#include "virt.h"
#define PREALLOC_TOKEN 2048
@@ -123,6 +125,7 @@ enum token_type {
TK_M_DEVLINK, /* val */
TK_M_NAME, /* val */
TK_M_ENV, /* val, attr */
+ TK_M_CONST, /* val, attr */
TK_M_TAG, /* val */
TK_M_SUBSYSTEM, /* val */
TK_M_DRIVER, /* val */
@@ -257,6 +260,7 @@ static const char *token_str(enum token_type type) {
[TK_M_DEVLINK] = "M DEVLINK",
[TK_M_NAME] = "M NAME",
[TK_M_ENV] = "M ENV",
+ [TK_M_CONST] = "M CONST",
[TK_M_TAG] = "M TAG",
[TK_M_SUBSYSTEM] = "M SUBSYSTEM",
[TK_M_DRIVER] = "M DRIVER",
@@ -365,6 +369,7 @@ static void dump_token(struct udev_rules *rules, struct token *token) {
case TK_M_ATTR:
case TK_M_ATTRS:
case TK_M_ENV:
+ case TK_M_CONST:
case TK_A_ATTR:
case TK_A_ENV:
log_debug("%s %s '%s' '%s'(%s)",
@@ -905,6 +910,7 @@ static int rule_add_key(struct rule_tmp *rule_tmp, enum token_type type,
token->key.builtin_cmd = *(enum udev_builtin_cmd *)data;
break;
case TK_M_ENV:
+ case TK_M_CONST:
case TK_M_ATTR:
case TK_M_ATTRS:
case TK_A_ATTR:
@@ -1264,6 +1270,22 @@ static int add_rule(struct udev_rules *rules, char *line,
continue;
}
+ if (startswith(key, "CONST{")) {
+ attr = get_key_attribute(rules->udev, key + STRLEN("CONST"));
+ if (attr == NULL || !STR_IN_SET(attr, "arch", "virt")) {
+ log_error("error parsing CONST attribute");
+ goto invalid;
+ }
+ if (op == OP_REMOVE) {
+ log_error("invalid CONST operation");
+ goto invalid;
+ }
+ if (op < OP_MATCH_MAX) {
+ if (rule_add_key(&rule_tmp, TK_M_CONST, op, value, attr) != 0)
+ goto invalid;
+ }
+ continue;
+ }
if (streq(key, "TAG")) {
if (op < OP_MATCH_MAX)
rule_add_key(&rule_tmp, TK_M_TAG, op, value, NULL);
@@ -1959,6 +1981,23 @@ int udev_rules_apply_to_event(struct udev_rules *rules,
goto nomatch;
break;
}
+ case TK_M_CONST: {
+ const char *key_name = rules_str(rules, cur->key.attr_off);
+ const char *value = NULL;
+ int q;
+
+ if (streq(key_name, "arch")) {
+ q = uname_architecture();
+ value = architecture_to_string(q);
+ } else if (streq(key_name, "virt")) {
+ q = detect_virtualization(&value);
+ } else
+ assert_not_reached("Invalid CONST key");
+
+ if (match_key(rules, cur, value))
+ goto nomatch;
+ break;
+ }
case TK_M_TAG: {
struct udev_list_entry *list_entry;
bool match = false;
diff --git a/test/rule-syntax-check.py b/test/rule-syntax-check.py
index 80bbe65bea..c6d003b167 100644
--- a/test/rule-syntax-check.py
+++ b/test/rule-syntax-check.py
@@ -34,7 +34,7 @@ else:
rules_files = glob(os.path.join(rules_dir, '*.rules'))
no_args_tests = re.compile('(ACTION|DEVPATH|KERNELS?|NAME|SYMLINK|SUBSYSTEMS?|DRIVERS?|TAG|RESULT|TEST)\s*(?:=|!)=\s*"([^"]*)"$')
-args_tests = re.compile('(ATTRS?|ENV|TEST){([a-zA-Z0-9/_.*%-]+)}\s*(?:=|!)=\s*"([^"]*)"$')
+args_tests = re.compile('(ATTRS?|ENV|CONST|TEST){([a-zA-Z0-9/_.*%-]+)}\s*(?:=|!)=\s*"([^"]*)"$')
no_args_assign = re.compile('(NAME|SYMLINK|OWNER|GROUP|MODE|TAG|PROGRAM|RUN|LABEL|GOTO|WAIT_FOR|OPTIONS|IMPORT)\s*(?:\+=|:=|=)\s*"([^"]*)"$')
args_assign = re.compile('(ATTR|ENV|IMPORT|RUN){([a-zA-Z0-9/_.*%-]+)}\s*(=|\+=)\s*"([^"]*)"$')