Use disk sector size value to set offset for reading GPT

[thirdparty/mdadm.git] / util.c

diff --git a/util.c b/util.c
index 9e4718fd988c8ed7de7ec3745deb480e75042f67..818f8392177e4ff584067d8e9ffec2c30e98cb31 100644 (file)
--- a/util.c
+++ b/util.c
@@ -1324,7 +1324,7 @@ int get_dev_size(int fd, char *dname, unsigned long long *sizep)
                        ldsize <<= 9;
                } else {
                        if (dname)
-                               pr_err("Cannot get size of %s: %s\b",
+                               pr_err("Cannot get size of %s: %s\n",
                                        dname, strerror(errno));
                        return 0;
                }
@@ -1333,6 +1333,22 @@ int get_dev_size(int fd, char *dname, unsigned long long *sizep)
        return 1;
 }
 
+/* Return sector size of device in bytes */
+int get_dev_sector_size(int fd, char *dname, unsigned int *sectsizep)
+{
+       unsigned int sectsize;
+
+       if (ioctl(fd, BLKSSZGET, &sectsize) != 0) {
+               if (dname)
+                       pr_err("Cannot get sector size of %s: %s\n",
+                               dname, strerror(errno));
+               return 0;
+       }
+
+       *sectsizep = sectsize;
+       return 1;
+}
+
 /* Return true if this can only be a container, not a member device.
  * i.e. is and md device and size is zero
  */
@@ -1362,12 +1378,15 @@ static int get_gpt_last_partition_end(int fd, unsigned long long *endofpart)
        unsigned long long curr_part_end;
        unsigned all_partitions, entry_size;
        unsigned part_nr;
+       unsigned int sector_size = 0;
 
        *endofpart = 0;
 
        BUILD_BUG_ON(sizeof(gpt) != 512);
        /* skip protective MBR */
-       lseek(fd, 512, SEEK_SET);
+       if (!get_dev_sector_size(fd, NULL, &sector_size))
+               return 0;
+       lseek(fd, sector_size, SEEK_SET);
        /* read GPT header */
        if (read(fd, &gpt, 512) != 512)
                return 0;
@@ -1387,6 +1406,8 @@ static int get_gpt_last_partition_end(int fd, unsigned long long *endofpart)
 
        part = (struct GPT_part_entry *)buf;
 
+       /* set offset to third block (GPT entries) */
+       lseek(fd, sector_size*2, SEEK_SET);
        for (part_nr = 0; part_nr < all_partitions; part_nr++) {
                /* read partition entry */
                if (read(fd, buf, entry_size) != (ssize_t)entry_size)