14243f8de7
The values of the d_slice and d_partition fields of a disk_devdesc have a few values with special meanings in the disk_open() routine. Through various evolutions of the loader code over time, a d_partition value of -1 has meant both "use the first ufs partition found in the bsd label" and "don't open a bsd partition at all, open the raw slice." This defines a new special value of -2 to mean open the raw slice, and it gives symbolic names to all the special values used in d_slice and d_partition, and adjusts all existing uses of those fields to use the new constants. The phab review for this timed out without being accepted, but I'm still citing it below because there is useful commentary there. Differential Revision: https://reviews.freebsd.org/D19262
123 lines
4.1 KiB
C
123 lines
4.1 KiB
C
/*-
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* Copyright (c) 2011 Google, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Device descriptor for partitioned disks. To use, set the
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* d_slice and d_partition variables as follows:
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*
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* Whole disk access:
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*
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* d_slice = D_SLICENONE
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* d_partition = <doesn't matter>
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*
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* Whole MBR slice:
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*
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* d_slice = MBR slice number (typically 1..4)
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* d_partition = D_PARTNONE
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*
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* BSD disklabel partition within an MBR slice:
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*
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* d_slice = MBR slice number (typically 1..4)
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* d_partition = disklabel partition (typically 0..19 or D_PARTWILD)
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*
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* BSD disklabel partition on the true dedicated disk:
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*
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* d_slice = D_SLICENONE
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* d_partition = disklabel partition (typically 0..19 or D_PARTWILD)
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*
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* GPT partition:
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*
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* d_slice = GPT partition number (typically 1..N)
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* d_partition = D_PARTISGPT
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*
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* For MBR, setting d_partition to D_PARTWILD will automatically use the first
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* partition within the slice.
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*
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* For both MBR and GPT, to automatically find the 'best' slice and partition,
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* set d_slice to D_SLICEWILD. This uses the partition type to decide which
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* partition to use according to the following list of preferences:
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*
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* FreeBSD (active)
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* FreeBSD (inactive)
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* Linux (active)
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* Linux (inactive)
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* DOS/Windows (active)
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* DOS/Windows (inactive)
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*
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* Active MBR slices (marked as bootable) are preferred over inactive. GPT
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* doesn't have the concept of active/inactive partitions. In both MBR and GPT,
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* if there are multiple slices/partitions of a given type, the first one
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* is chosen.
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*
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* The low-level disk device will typically call disk_open() from its open
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* method to interpret the disk partition tables according to the rules above.
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* This will initialize d_offset to the block offset of the start of the
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* selected partition - this offset should be added to the offset passed to
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* the device's strategy method.
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*/
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#ifndef _DISK_H
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#define _DISK_H
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#define D_SLICENONE -1
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#define D_SLICEWILD 0
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#define D_PARTNONE -1
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#define D_PARTWILD -2
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#define D_PARTISGPT 255
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struct disk_devdesc {
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struct devdesc dd; /* Must be first. */
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int d_slice;
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int d_partition;
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uint64_t d_offset;
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};
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enum disk_ioctl {
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IOCTL_GET_BLOCKS,
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IOCTL_GET_BLOCK_SIZE
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};
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/*
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* Parse disk metadata and initialise dev->d_offset.
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*/
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extern int disk_open(struct disk_devdesc *, uint64_t, u_int);
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extern int disk_close(struct disk_devdesc *);
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extern int disk_ioctl(struct disk_devdesc *, u_long, void *);
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extern int disk_read(struct disk_devdesc *, void *, uint64_t, u_int);
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extern int disk_write(struct disk_devdesc *, void *, uint64_t, u_int);
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extern int ptblread(void *, void *, size_t, uint64_t);
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/*
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* Print information about slices on a disk.
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*/
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extern int disk_print(struct disk_devdesc *, char *, int);
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extern char* disk_fmtdev(struct disk_devdesc *);
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extern int disk_parsedev(struct disk_devdesc *, const char *, const char **);
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#endif /* _DISK_H */
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