[PATCH] cleanup mult field string handling

Here I try to cleanup our various multifield iteration over the strings.
Inspired by our nice list.h we now have a macro to iterate over the string
and process the parts of it:
It makes the code more readable and we don't change the string while we
process it like the former strsep() does.

Example:

  foreach_strpart(dev->symlink, " ", pos, len) {
  	if (strncmp(&dev->symlink[pos], find_name, len) != 0)
  		continue;

  	...
  }

For the callout part selector %c{2} we separate now not only by space but
also newline and return characters, cause some programs may give multiline
values back. A possible RESULT match must contain wildcards for these
characters.

Also a bug in the recent udevinfo symlink query feature is fixed.

1 files changed, 6 insertions, 0 deletions

diff --git a/udev.h b/udev.h
index 5737c84c9d..9327e90913 100644
--- a/udev.h
+++ b/udev.h
@@ -97,6 +97,12 @@ do { \
 	snprintf((to) + strlen(to), maxsize - strlen(to)-1, "%u", i); \
 } while (0)
 
+#define foreach_strpart(str, separator, pos, len) \
+	for(pos = 0, len = strcspn(str, separator); \
+	    (pos) < strlen(str); \
+	    pos = pos + (len) + 1, len = strcspn((str) + pos, separator)) \
+		if (len > 0)
+
 static inline char *get_action(void)
 {
 	char *action;