exec: Stricter pathopt parsing

This patch changes the parsing of pathopt.  First of all only
%builtin and %func (with arbitrary suffixes) will be recognised.
Any other pathopt will be treated as a normal directory.

Furthermore, pathopt can now be specified before the directory,
rather than after it.  In fact, a future version may remove support
for pathopt suffixes.

Wherever the pathopt is placed, an optional % may be placed after
it to terminate the pathopt.

This is so that it is less likely that a genuine directory containing
a % sign is parsed as a pathopt.

Users of padvance outside of exec.c have also been modified:

1) cd(1) will always treat % characters as part of the path.
2) chkmail will continue to accept arbitrary pathopt.
3) find_dot_file will ignore the %builtin pathopt instead of trying
to do a stat in the accompanying directory (which is usually the
current directory).

The patch also removes the clearcmdentry optimisation where we
attempt to only partially flush the table where possible.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/main.c b/src/main.c
index c87fbd7..e8e4256 100644
--- a/src/main.c
+++ b/src/main.c
@@ -300,7 +300,8 @@ find_dot_file(char *basename)
 
 	while ((len = padvance(&path, basename)) >= 0) {
 		fullname = stackblock();
-		if ((stat(fullname, &statb) == 0) && S_ISREG(statb.st_mode)) {
+		if ((!pathopt || *pathopt == 'f') &&
+		    !stat(fullname, &statb) && S_ISREG(statb.st_mode)) {
 			/* This will be freed by the caller. */
 			return stalloc(len);
 		}