sysfs: helper routine to retrieve the scsi id

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

diff --git a/mdadm.h b/mdadm.h
index f29cf0180f9740cbdba937df7a1f89f8eb3e59e3..bc3d4ea0ce87f01b0f0505aff00dc2a3be03a2a8 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -347,7 +347,7 @@ extern int sysfs_set_array(struct mdinfo *sra,
                           struct mdinfo *info);
 extern int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd);
 extern int sysfs_disk_to_sg(int fd);
-
+extern int sysfs_disk_to_scsi_id(int fd, __u32 *id);
 
 
 extern int save_stripes(int *source, unsigned long long *offsets,

diff --git a/sysfs.c b/sysfs.c
index 37b8b0974a142121be5ba6d9f7556dac33376427..5f0c212741cae8792b4689f4a13f149de90d8c57 100644 (file)
--- 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;
+}