diff options
Diffstat (limited to 'sys/geom/geom_gpt.c')
| -rw-r--r-- | sys/geom/geom_gpt.c | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/sys/geom/geom_gpt.c b/sys/geom/geom_gpt.c index aa074ee..24aa3c9 100644 --- a/sys/geom/geom_gpt.c +++ b/sys/geom/geom_gpt.c @@ -360,31 +360,50 @@ g_gpt_has_pmbr(struct g_consumer *cp, int *error) { char *buf; uint8_t *typ; - int i, pmbr; + int i, pmbr, vmbr; uint16_t magic; + uint32_t dp_start, dp_size; buf = g_read_data(cp, 0L, cp->provider->sectorsize, error); if (buf == NULL) return (0); pmbr = 0; + vmbr = 0; magic = le16toh(*(uint16_t *)(uintptr_t)(buf + DOSMAGICOFFSET)); if (magic != DOSMAGIC) goto out; + /* + * Check that there are at least one partition of type + * DOSPTYP_PMBR that covers the whole unit. + */ for (i = 0; i < 4; i++) { typ = buf + DOSPARTOFF + i * sizeof(struct dos_partition) + offsetof(struct dos_partition, dp_typ); + bcopy(buf + DOSPARTOFF + i * sizeof(struct dos_partition) + + offsetof(struct dos_partition, dp_start), &dp_start, sizeof(dp_start)); + bcopy(buf + DOSPARTOFF + i * sizeof(struct dos_partition) + + offsetof(struct dos_partition, dp_size), &dp_size, sizeof(dp_size)); + if ((*typ == DOSPTYP_PMBR) && + (le32toh(dp_start) == 1) && + (cp->provider->mediasize == + (le32toh(dp_size) * 512ULL))) { + pmbr = 1; + break; + } if (*typ != 0 && *typ != DOSPTYP_PMBR) - goto out; + vmbr = 1; } - pmbr = 1; - out: g_free(buf); - return (pmbr); + /* + * Return true if protective MBR is detected or if MBR has + * no valid entries at all. + */ + return (pmbr || !vmbr); } static void |
