Re: udev.rules.devfs + symlinks & a question

[Kay Sievers <kay.sievers@vrfy.org>]

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On Sat, Dec 13, 2003 at 02:17:22AM +0100, Svetoslav Slavtchev wrote:

> can a callout return several strings?
> NAME="%c1", SYMLINK="%c2 %c3"
> 
> no i don't think this can be done with a callout script

Try this patch if you like, to get special parts of the callout output.
This beast works now:
CALLOUT, BUS="scsi", PROGRAM="/bin/echo -n node link1 link2", ID="node *", NAME="%1c", SYMLINK="%2c %3c"

The callout returned string is separated by spaces and is
addressed by the "len" value of the 'c' format char.
Since we support symlinks, this my be useful for other uses of callout too.

good luck,
Kay



02-get-part-of-callout-return-string.diff
  introduce 'len number' for format chars
  the first use is 'c'-the callout return to select a part of the output string like:
  CALLOUT, BUS="scsi", PROGRAM="/bin/echo -n node link1 link2", ID="node *", NAME="%1c", SYMLINK="%2c %3c"
  (note: first part is requested by len=1, len=0 will return the whole string)
  add a test to udev-test.pl

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diff -Nru a/namedev.c b/namedev.c
--- a/namedev.c	Sat Dec 13 16:19:27 2003
+++ b/namedev.c	Sat Dec 13 16:19:27 2003
@@ -200,15 +200,30 @@
 static void apply_format(struct udevice *udev, unsigned char *string)
 {
 	char name[NAME_SIZE];
+	char temp[NAME_SIZE];
+	char *tail;
 	char *pos;
+	char *pos2;
+	char *pos3;
+	int num;
 
 	while (1) {
+		num = 0;
 		pos = strchr(string, '%');
 
 		if (pos) {
-			strfieldcpy(name, pos+2);
-			*pos = 0x00;
-			switch (pos[1]) {
+			*pos = '\0';
+			tail = pos+1;
+			if (isdigit(tail[0])) {
+				num = (int) strtoul(&pos[1], &tail, 10);
+				if (tail == NULL) {
+					dbg("format parsing error '%s'", pos+1);
+					break;
+				}
+			}
+			strfieldcpy(name, tail+1);
+
+			switch (tail[0]) {
 			case 'b':
 				if (strlen(udev->bus_id) == 0)
 					break;
@@ -241,8 +256,24 @@
 			case 'c':
 				if (strlen(udev->callout_value) == 0)
 					break;
-				strcat(pos, udev->callout_value);
-				dbg("substitute callout output '%s'", udev->callout_value);
+				if (num) {
+					/* get part of return string */
+					strncpy(temp, udev->callout_value, sizeof(temp));
+					pos2 = temp;
+					while (num) {
+						num--;
+						pos3 = strsep(&pos2, " ");
+						if (pos3 == NULL) {
+							dbg("requested part of callout string not found");
+							break;
+						}
+					}
+					strcat(pos, pos3);
+					dbg("substitute partial callout output '%s'", pos3);
+				} else {
+					strcat(pos, udev->callout_value);
+					dbg("substitute callout output '%s'", udev->callout_value);
+				}
 				break;
 			default:
 				dbg("unknown substitution type '%%%c'", pos[1]);
diff -Nru a/test/udev-test.pl b/test/udev-test.pl
--- a/test/udev-test.pl	Sat Dec 13 16:19:27 2003
+++ b/test/udev-test.pl	Sat Dec 13 16:19:27 2003
@@ -153,6 +153,15 @@
 EOF
 	},
 	{
+		desc     => "callout program substitution (numbered part of)",
+		subsys   => "block",
+		devpath  => "block/sda/sda3",
+		expected => "link1" ,
+		conf     => <<EOF
+CALLOUT, BUS="scsi", PROGRAM="/bin/echo -n node link1 link2", ID="node *", NAME="%1c", SYMLINK="%2c %3c"
+EOF
+	},
+	{
 		desc     => "devfs disk naming substitution",
 		subsys   => "block",
 		devpath  => "block/sda",