libmultipath: sanitize fd handling

One should remember that '0' _is_ a valid fd, so we need to set the fd to '-1' upon allocating the path structure and ensure we're checking for a value _smaller_ than 0 to detect an invalid fd.

libmultipath/print.c int snprint_status(char *buff, int len,

Quoted 28 lines

libmultipath/checkers.c +1 -1

index 05e024f8..c32f7274 100644
@@ -146,7 +146,7 @@ struct checker * add_checker (char
 *multipath_dir, char * name)
 	if (!c->repair)
 		goto out;
 
-	c->fd = 0;
+	c->fd = -1;
 	c->sync = 1;
 	list_add(&c->node, &checkers);

libmultipath/checkers.c +1 -1

 	return c;

@@ -237,7 +237,7 @@ int checker_check (struct checker * c)
 		MSG(c, "checker disabled");
 		return PATH_UNCHECKED;
 	}
-	if (c->fd <= 0) {
+	if (c->fd < 0) {
 		MSG(c, "no usable fd");
 		return PATH_WILD;
 	}

libmultipath/print.c +0 -0

index 95dff90b..65a98247 100644
@@ -1677,7 +1677,7 @@ int snprint_status(char *buff, int len,

struct

Quoted 10 lines

libmultipath/print.c +1 -1

 vectors *vecs)
 	int monitored_count = 0;
 
 	vector_foreach_slot(vecs->pathvec, pp, i)
-		if (pp->fd != -1)
+		if (pp->fd >= 0)
 			monitored_count++;
 	fwd += snprintf(buff + fwd, len - fwd, "\npaths: %d\nbusy:

%s\n",
monitored_count, is_uevent_busy()? "True"

:

Quoted 1 line

"False");

Signed-off-by Hannes Reinecke <[email protected]>

---
 libmultipath/checkers.c | 4 ++--
 libmultipath/print.c    | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

Quoted 7 lines · Hannes Reinecke

Signed-off-by Hannes Reinecke <[email protected]>

---
 libmultipath/checkers.c | 4 ++--
 libmultipath/print.c    | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

There's one more wrong fd reference in libmultipath/checkers/cciss_tur.c:76. And a nitpick: The comment in checkers.h:14 should be fixed as well.

Apart from that: nice (although not strictly necessary, as multipathd currently runs with fd 0 connected to /dev/null under normal conditions).