sysfs_is_multipathed reads the wwid of the dm device holding a path to
check if its a multipath device.  Add code to optinally set pp->wwid to
that wwid.  This will be used by a future patch.

Signed-off-by: Benjamin Marzinski <bmarz...@redhat.com>
---
 libmultipath/sysfs.c | 22 +++++++++++++++++++---
 libmultipath/sysfs.h |  2 +-
 multipath/main.c     |  7 ++++---
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/libmultipath/sysfs.c b/libmultipath/sysfs.c
index 62ec2ed7..034f082f 100644
--- a/libmultipath/sysfs.c
+++ b/libmultipath/sysfs.c
@@ -295,7 +295,7 @@ static int select_dm_devs(const struct dirent *di)
        return fnmatch("dm-*", di->d_name, FNM_FILE_NAME) == 0;
 }
 
-bool sysfs_is_multipathed(const struct path *pp)
+bool sysfs_is_multipathed(struct path *pp, bool set_wwid)
 {
        char pathbuf[PATH_MAX];
        struct scandir_result sr;
@@ -342,9 +342,25 @@ bool sysfs_is_multipathed(const struct path *pp)
                if (nr == sizeof(uuid) && !memcmp(uuid, "mpath-", sizeof(uuid)))
                        found = true;
                else if (nr < 0) {
-                       condlog(1, "%s: error reading from %s: %s",
-                               __func__, pathbuf, strerror(errno));
+                       condlog(1, "%s: error reading from %s: %m",
+                               __func__, pathbuf);
                }
+               if (found && set_wwid) {
+                       nr = read(fd, pp->wwid, WWID_SIZE);
+                       if (nr < 0) {
+                               condlog(1, "%s: error reading from %s: %m",
+                                       __func__, pathbuf);
+                               pp->wwid[0] = '\0';
+                       } else if (nr == WWID_SIZE) {
+                               condlog(4, "%s: overflow while reading from %s",
+                                       __func__, pathbuf);
+                               pp->wwid[0] = '\0';
+                       } else {
+                               pp->wwid[nr] = '\0';
+                               strchop(pp->wwid);
+                       }
+                }
+
                pthread_cleanup_pop(1);
        }
        pthread_cleanup_pop(1);
diff --git a/libmultipath/sysfs.h b/libmultipath/sysfs.h
index 9ae30b39..72b39ab2 100644
--- a/libmultipath/sysfs.h
+++ b/libmultipath/sysfs.h
@@ -14,5 +14,5 @@ ssize_t sysfs_bin_attr_get_value(struct udev_device *dev, 
const char *attr_name,
                                 unsigned char * value, size_t value_len);
 int sysfs_get_size (struct path *pp, unsigned long long * size);
 int sysfs_check_holders(char * check_devt, char * new_devt);
-bool sysfs_is_multipathed(const struct path *pp);
+bool sysfs_is_multipathed(struct path *pp, bool set_wwid);
 #endif
diff --git a/multipath/main.c b/multipath/main.c
index cf9d2a28..545ead87 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -638,7 +638,8 @@ configure (struct config *conf, enum mpath_cmds cmd,
                         * Shortcut for find_multipaths smart:
                         * Quick check if path is already multipathed.
                         */
-                       if (sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0))) {
+                       if (sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0),
+                                                false)) {
                                r = RTVL_YES;
                                goto print_valid;
                        }
@@ -747,8 +748,8 @@ configure (struct config *conf, enum mpath_cmds cmd,
                        /*
                         * Check if we raced with multipathd
                         */
-                       r = sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0)) ?
-                               RTVL_YES : RTVL_NO;
+                       r = sysfs_is_multipathed(VECTOR_SLOT(pathvec, 0),
+                                                false) ? RTVL_YES : RTVL_NO;
                }
                goto print_valid;
        }
-- 
2.17.2

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