incorporate Fedora patch for sector sizes > 512 bytes

[debian/efibootmgr] / src / lib / disk.c

diff --git a/src/lib/disk.c b/src/lib/disk.c
index 883864f4b06ceae0b172c6a09f0de232ca3c97f6..ebfe6199a69b1385fc82439d8c5521ef20dc4c69 100644 (file)
--- a/src/lib/disk.c
+++ b/src/lib/disk.c
@@ -420,6 +420,27 @@ get_sector_size(int filedes)
        return sector_size;
 }
 
+/************************************************************
+ * lcm
+ * Requires:
+ * - numbers of which to find the lowest common multiple
+ * Modifies: nothing
+ * Returns:
+ *  lowest common multiple of x and y
+ ************************************************************/
+unsigned int
+lcm(unsigned int x, unsigned int y)
+{
+       unsigned int m = x, n = y, o;
+
+       while ((o = m % n)) {
+               m = n;
+               n = o;
+       }
+
+       return (x / n) * y;
+}
+
 /**
  * disk_get_partition_info()
  *  @fd - open file descriptor to disk
@@ -442,26 +463,27 @@ disk_get_partition_info (int fd,
                         uint8_t *mbr_type, uint8_t *signature_type)
 {
        legacy_mbr *mbr;
-       void *mbr_unaligned;
+       void *mbr_sector;
+       size_t mbr_size;
        off_t offset;
        int this_bytes_read = 0;
        int gpt_invalid=0, mbr_invalid=0;
        int rc=0;
        int sector_size = get_sector_size(fd);
 
-       if (sizeof(*mbr) != sector_size)
-               return 1;
-       mbr_unaligned = malloc(sizeof(*mbr)+sector_size-1);
-       mbr = (legacy_mbr *)
-               (((unsigned long)mbr_unaligned + sector_size - 1) &
-                ~(unsigned long)(sector_size-1));
-       memset(mbr, 0, sizeof(*mbr));
+
+       mbr_size = lcm(sizeof(*mbr), sector_size);
+       if ((rc = posix_memalign(&mbr_sector, sector_size, mbr_size)) != 0)
+               goto error;
+       memset(mbr_sector, '\0', mbr_size);
+
        offset = lseek(fd, 0, SEEK_SET);
-       this_bytes_read = read(fd, mbr, sizeof(*mbr));
+       this_bytes_read = read(fd, mbr_sector, mbr_size);
        if (this_bytes_read < sizeof(*mbr)) {
                rc=1;
                goto error_free_mbr;
        }
+       mbr = (legacy_mbr *)mbr_sector;
        gpt_invalid = gpt_disk_get_partition_info(fd, num,
                                                  start, size,
                                                  signature,
@@ -479,7 +501,8 @@ disk_get_partition_info (int fd,
                }
        }
  error_free_mbr:
-       free(mbr_unaligned);
+       free(mbr_sector);
+ error:
        return rc;
 }