diff options
| author | Kenneth R Westerback <krw@cvs.openbsd.org> | 2022-07-26 14:30:38 +0000 |
|---|---|---|
| committer | Kenneth R Westerback <krw@cvs.openbsd.org> | 2022-07-26 14:30:38 +0000 |
| commit | 59478e0b2f531e97853e9e7e1cd85a60e1a07a30 (patch) | |
| tree | 6d9f854eac4e571e3764f2de4dc23ab929a08fc2 /sbin/fdisk | |
| parent | 832416761d223ca851f94bb5f0925ccd25f294a9 (diff) | |
Allow editing of an MBR of all zeros.
Fallout from regress failure spotted by anton@.
Diffstat (limited to 'sbin/fdisk')
| -rw-r--r-- | sbin/fdisk/mbr.c | 13 | ||||
| -rw-r--r-- | sbin/fdisk/mbr.h | 3 |
2 files changed, 13 insertions, 3 deletions
diff --git a/sbin/fdisk/mbr.c b/sbin/fdisk/mbr.c index 2ef6783110f..6e6b6c58caf 100644 --- a/sbin/fdisk/mbr.c +++ b/sbin/fdisk/mbr.c @@ -1,4 +1,4 @@ -/* $OpenBSD: mbr.c,v 1.120 2022/07/25 17:45:16 krw Exp $ */ +/* $OpenBSD: mbr.c,v 1.121 2022/07/26 14:30:37 krw Exp $ */ /* * Copyright (c) 1997 Tobias Weingartner @@ -105,7 +105,13 @@ dos_mbr_to_mbr(const struct dos_mbr *dmbr, const uint64_t lba_self, const uint64_t lba_firstembr, struct mbr *mbr) { struct dos_partition dos_parts[NDOSPART]; - int i; + uint8_t *p; + unsigned int i; + + p = (uint8_t *)dmbr; + mbr->mbr_dmbrzeros = 0; + for (i = 0; i < sizeof(struct dos_mbr) && *p == 0; i++, p++) + mbr->mbr_dmbrzeros++; memcpy(mbr->mbr_code, dmbr->dmbr_boot, sizeof(mbr->mbr_code)); mbr->mbr_lba_self = lba_self; @@ -188,6 +194,9 @@ MBR_valid_prt(const struct mbr *mbr) unsigned int i, nprt; unsigned char id; + if (mbr->mbr_dmbrzeros == sizeof(struct dos_mbr)) + return 1; /* All zeros struct dos_mbr is editable. */ + nprt = 0; for (i = 0; i < NDOSPART; i++) { bs = mbr->mbr_prt[i].prt_bs; diff --git a/sbin/fdisk/mbr.h b/sbin/fdisk/mbr.h index 0c56a3db4e0..3aee1dabdb5 100644 --- a/sbin/fdisk/mbr.h +++ b/sbin/fdisk/mbr.h @@ -1,4 +1,4 @@ -/* $OpenBSD: mbr.h,v 1.43 2022/07/25 17:45:16 krw Exp $ */ +/* $OpenBSD: mbr.h,v 1.44 2022/07/26 14:30:37 krw Exp $ */ /* * Copyright (c) 1997 Tobias Weingartner @@ -22,6 +22,7 @@ struct mbr { unsigned char mbr_code[DOSPARTOFF]; struct prt mbr_prt[NDOSPART]; uint16_t mbr_signature; + unsigned int mbr_dmbrzeros; }; extern struct dos_mbr default_dmbr; |