add substitution in MODE= field

Do substitition processing in MODE field, similar to substitution in
OWNER, GROUP etc fields.  Add test case for normal and overflow behaviour.
Document in manpage.

4 files changed, 39 insertions, 7 deletions

diff --git a/test/udev-test.pl b/test/udev-test.pl
index fee62a6406..72b4aef6bc 100755
--- a/test/udev-test.pl
+++ b/test/udev-test.pl
@@ -1617,6 +1617,27 @@ EOF
 KERNEL=="sda", MODE="0000"
 EOF
 	},
+	{
+		desc		=> "TEST PROGRAM feeds MODE",
+		subsys		=> "block",
+		devpath		=> "/block/sda",
+		exp_name	=> "sda",
+		exp_perms	=> "0:0:0400",
+		rules		=> <<EOF
+KERNEL=="sda", PROGRAM=="/bin/echo 0 0 0400", OWNER="%c{1}", GROUP="%c{2}", MODE="%c{3}"
+EOF
+	},
+	{
+		desc		=> "TEST PROGRAM feeds MODE with overflow",
+		subsys		=> "block",
+		devpath		=> "/block/sda",
+		exp_name	=> "sda",
+		exp_perms	=> "0:0:0400",
+		rules		=> <<EOF
+KERNEL=="sda", PROGRAM=="/bin/echo 0 0 0400letsdoabuffferoverflow0123456789012345789012345678901234567890", OWNER="%c{1}", GROUP="%c{2}", MODE="%c{3}"
+EOF
+	},
+
 );
 
 # set env
@@ -1732,6 +1753,15 @@ sub symlink_test {
 	}
 }
 
+sub make_udev_root {
+	system("rm -rf $udev_root");
+	mkdir($udev_root) || die "unable to create udev_root: $udev_root\n";
+	# setting group and mode of udev_root ensures the tests work
+	# even if the parent directory has setgid bit enabled.
+	chown (0, 0, $udev_root) || die "unable to chown $udev_root\n";
+	chmod (0755, $udev_root) || die "unable to chmod $udev_root\n";
+}
+
 sub run_test {
 	my ($rules, $number) = @_;
 
@@ -1804,8 +1834,7 @@ sub run_test {
 	print "\n";
 
 	if (defined($rules->{option}) && $rules->{option} eq "clean") {
-		system("rm -rf $udev_root");
-		mkdir($udev_root) || die "unable to create udev_root: $udev_root\n";
+		make_udev_root ();
 	}
 
 }
@@ -1818,8 +1847,7 @@ if (!($<==0)) {
 }
 
 # prepare
-system("rm -rf $udev_root");
-mkdir($udev_root) || die "unable to create udev_root: $udev_root\n";
+make_udev_root ();
 
 # create config file
 open CONF, ">$udev_conf" || die "unable to create config file: $udev_conf";
diff --git a/udev.7 b/udev.7
index 096bf38554..79e61ea9f4 100644
--- a/udev.7
+++ b/udev.7
@@ -307,7 +307,8 @@ The
 \fBSYMLINK\fR,
 \fBPROGRAM\fR,
 \fBOWNER\fR,
-\fBGROUP\fR
+\fBGROUP\fR,
+\fBMODE\fR
 and
 \fBRUN\fR
 fields support simple printf\-like string substitutions\. The
diff --git a/udev.xml b/udev.xml
index ac3676e466..184457aa6c 100644
--- a/udev.xml
+++ b/udev.xml
@@ -462,7 +462,7 @@
           </variablelist>
 
           <para>The <option>NAME</option>, <option>SYMLINK</option>, <option>PROGRAM</option>,
-          <option>OWNER</option>, <option>GROUP</option>  and  <option>RUN</option>
+          <option>OWNER</option>, <option>GROUP</option>, <option>MODE</option>  and  <option>RUN</option>
           fields support simple printf-like string substitutions. The <option>RUN</option>
           format chars gets applied after all rules have been processed, right before the program
           is executed. It allows the use of the complete environment set by earlier matching
diff --git a/udev_rules.c b/udev_rules.c
index 55a079be87..f4ee11a56c 100644
--- a/udev_rules.c
+++ b/udev_rules.c
@@ -1412,7 +1412,10 @@ int udev_rules_get_name(struct udev_rules *rules, struct udevice *udev)
 			if (!udev->mode_final && rule->mode.operation != KEY_OP_UNSET) {
 				if (rule->mode.operation == KEY_OP_ASSIGN_FINAL)
 					udev->mode_final = 1;
-				udev->mode = strtol(key_val(rule, &rule->mode), NULL, 8);
+				char buf[20];
+				strlcpy(buf, key_val(rule, &rule->mode), sizeof(buf));
+				udev_rules_apply_format(udev, buf, sizeof(buf));
+				udev->mode = strtol(buf, NULL, 8);
 				dbg("applied mode=%#o to '%s'\n", udev->mode, udev->dev->kernel);
 			}
 			if (!udev->owner_final && rule->owner.operation != KEY_OP_UNSET) {