sysfs: helper routine to retrieve the scsi id

imsm records this information in its metadata

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/sysfs.c b/sysfs.c
index 37b8b09..5f0c212 100644
--- a/sysfs.c
+++ b/sysfs.c
@@ -464,3 +464,52 @@ int sysfs_disk_to_sg(int fd)
 	return -1;
 }
 
+int sysfs_disk_to_scsi_id(int fd, __u32 *id)
+{
+	/* from an open block device, try to retrieve it scsi_id */
+	struct stat st;
+	char path[256];
+	char *c1, *c2;
+	DIR *dir;
+	struct dirent *de;
+
+	if (fstat(fd, &st))
+		return 1;
+
+	snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
+		 major(st.st_rdev), minor(st.st_rdev));
+
+	dir = opendir(path);
+	if (!dir)
+		return 1;
+
+	de = readdir(dir);
+	while (de) {
+		if (strncmp("scsi_disk:", de->d_name,
+			    strlen("scsi_disk:")) == 0)
+			break;
+		de = readdir(dir);
+	}
+	closedir(dir);
+
+	if (!de)
+		return 1;
+
+	c1 = strchr(de->d_name, ':');
+	c1++;
+	c2 = strchr(c1, ':');
+	*c2 = '\0';
+	*id = strtol(c1, NULL, 10) << 24; /* host */
+	c1 = c2 + 1;
+	c2 = strchr(c1, ':');
+	*c2 = '\0';
+	*id |= strtol(c1, NULL, 10) << 16; /* channel */
+	c1 = c2 + 1;
+	c2 = strchr(c1, ':');
+	*c2 = '\0';
+	*id |= strtol(c1, NULL, 10) << 8; /* lun */
+	c1 = c2 + 1;
+	*id |= strtol(c1, NULL, 10); /* id */
+
+	return 0;
+}