[PATCH] conditional remove of trailing sysfs whitespace

Hey, it may never happen, that one wants to distinguish attributes by
trailing spaces, but we should not lose the control over it, just for
being lazy :)

Here we remove the trailing spaces of the sysfs attribute only if the
configured value to match doesn't have any trailing spaces by itself.
So if you put a attribute in a rule with spaces at the end, the sysfs
attribute _must_ match exactly.

Is that cool for everyone?

As usual, 2 tests are added for it with a artificial sysfs file and
a few words to the man page.

4 files changed, 37 insertions, 0 deletions

diff --git a/namedev.c b/namedev.c
index 9182ed1fdc..dfeadee18a 100644
--- a/namedev.c
+++ b/namedev.c
@@ -525,6 +525,8 @@ attr_found:
 static int compare_sysfs_attribute(struct sysfs_class_device *class_dev, struct sysfs_device *sysfs_device, struct sysfs_pair *pair)
 {
 	struct sysfs_attribute *tmpattr;
+	int i;
+	int len;
 
 	if ((pair == NULL) || (pair->file[0] == '\0') || (pair->value == '\0'))
 		return -ENODEV;
@@ -533,6 +535,18 @@ static int compare_sysfs_attribute(struct sysfs_class_device *class_dev, struct
 	if (tmpattr == NULL)
 		return -ENODEV;
 
+	/* strip trailing whitespace of value, if not asked to match for it */
+	if (! isspace(pair->value[strlen(pair->value)-1])) {
+		i = len = strlen(tmpattr->value);
+		while (i > 0 &&  isspace(tmpattr->value[i-1]))
+			i--;
+		if (i < len) {
+			tmpattr->value[i] = '\0';
+			dbg("remove %i trailing whitespace chars from '%s'",
+			    len - i, tmpattr->value);
+		}
+	}
+
 	dbg("compare attribute '%s' value '%s' with '%s'",
 		  pair->file, tmpattr->value, pair->value);
 	if (strcmp_pattern(pair->value, tmpattr->value) != 0)
diff --git a/test/sys/devices/pci0000:00/0000:00:1e.0/0000:02:05.0/host0/0:0:0:0/whitespace_test b/test/sys/devices/pci0000:00/0000:00:1e.0/0000:02:05.0/host0/0:0:0:0/whitespace_test
new file mode 100644
index 0000000000..e3d48f0fe0
--- /dev/null
+++ b/test/sys/devices/pci0000:00/0000:00:1e.0/0000:02:05.0/host0/0:0:0:0/whitespace_test
@@ -0,0 +1 @@
+WHITE  SPACE   
diff --git a/test/udev-test.pl b/test/udev-test.pl
index 60cf16901c..38ea0181f6 100644
--- a/test/udev-test.pl
+++ b/test/udev-test.pl
@@ -467,6 +467,25 @@ BUS="scsi", ID="*:0:0:0", NAME="scsi-0:0:0:0"
 BUS="scsi", ID="0:0:0:0", NAME="bad"
 EOF
 	},
+	{
+		desc     => "ignore SYSFS attribute whitespace",
+		subsys   => "block",
+		devpath  => "block/sda",
+		expected => "ignored",
+		conf     => <<EOF
+BUS="scsi", SYSFS{whitespace_test}="WHITE  SPACE", NAME="ignored"
+EOF
+	},
+	{
+		desc     => "do not ignore SYSFS attribute whitespace",
+		subsys   => "block",
+		devpath  => "block/sda",
+		expected => "matched-with-space",
+		conf     => <<EOF
+BUS="scsi", SYSFS{whitespace_test}="WHITE  SPACE ", NAME="wrong-to-ignore"
+BUS="scsi", SYSFS{whitespace_test}="WHITE  SPACE   ", NAME="matched-with-space"
+EOF
+	},
 );
 
 # set env
diff --git a/udev.8 b/udev.8
index bc7308f484..76b8913f03 100644
--- a/udev.8
+++ b/udev.8
@@ -178,6 +178,9 @@ Match the topological position on bus, like physical port of USB device
 Match sysfs device attribute like label, vendor, USB serial number, SCSI UUID
 or file system label.  Up to 5 different sysfs files can be checked, with
 all of the values being required in order to match the rule.
+.br
+Trailing whitespace characters in the sysfs attribute value are ignored, if
+the key doesn't have any trailing whitespace characters by itself.
 .TP
 .B PROGRAM
 Call external program. This key is valid if the program returns successful.