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partitions.c revision 1.2 
      1 /*	$NetBSD: partitions.c,v 1.2 2019/08/14 13:02:23 martin Exp $	*/
      2 
      3 /*
      4  * Copyright 2018 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY PIERMONT INFORMATION SYSTEMS INC. ``AS IS''
     17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED. IN NO EVENT SHALL PIERMONT INFORMATION SYSTEMS INC. BE
     20  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     26  * THE POSSIBILITY OF SUCH DAMAGE.
     27  *
     28  */
     29 
     30 #include "defs.h"
     31 #include "mbr.h"
     32 #include <assert.h>
     33 
     34 /*
     35  * A list of partitioning schemes, so we can iterate over everything
     36  * supported (e.g. when partitioning a new disk). NULL terminated.
     37  */
     38 const struct disk_partitioning_scheme **available_part_schemes;
     39 /*
     40  * The number of valid entries on above list
     41  */
     42 size_t num_available_part_schemes;
     43 
     44 /*
     45  * Generic reader - query a disk device and read all partitions from it
     46  */
     47 struct disk_partitions *
     48 partitions_read_disk(const char *dev, daddr_t disk_size)
     49 {
     50 	const struct disk_partitioning_scheme **ps;
     51 
     52 	if (!available_part_schemes)
     53 		return NULL;
     54 
     55 	for (ps = available_part_schemes; *ps; ps++) {
     56 		struct disk_partitions *parts =
     57 		    (*ps)->read_from_disk(dev, 0, disk_size, *ps);
     58 		if (parts)
     59 			return parts;
     60 	}
     61 	return NULL;
     62 }
     63 
     64 /*************** global init ****************************************/
     65 /*
     66  * Helper structure to fill our global list of available partitioning
     67  * schemes.
     68  */
     69 struct part_scheme_desc {
     70 	bool (*is_available)(void);
     71 	const struct disk_partitioning_scheme *ps;
     72 };
     73 
     74 #ifdef HAVE_GPT
     75 bool gpt_parts_check(void);
     76 extern const struct disk_partitioning_scheme gpt_parts;
     77 #endif
     78 #ifdef HAVE_MBR
     79 extern const struct disk_partitioning_scheme mbr_parts;
     80 #endif
     81 
     82 extern const struct disk_partitioning_scheme disklabel_parts;
     83 #if RAW_PART != 2
     84 static struct disk_partitioning_scheme only_disklabel_parts;
     85 
     86 /*
     87  * If not overriden by MD code, we can not boot from plain
     88  * disklabel disks (w/o MBR).
     89  */
     90 static bool have_only_disklabel_boot_support(const char *disk)
     91 {
     92 #ifdef HAVE_PLAIN_DISKLABEL_BOOT
     93 	return HAVE_PLAIN_DISKLABEL_BOOT(disk);
     94 #else
     95 	return false;
     96 #endif
     97 }
     98 #endif
     99 
    100 /*
    101  * One time initialization
    102  */
    103 void
    104 partitions_init(void)
    105 {
    106 	/*
    107 	 * List of partitioning schemes.
    108 	 * Order is important, the selection menu is created from start
    109 	 * to end. Keep good defaults early. Most architectures will
    110 	 * only offer very few entries.
    111 	 */
    112 static const struct part_scheme_desc all_descs[] = {
    113 #if RAW_PART == 2	/* only available as primary on some architectures */
    114 		{ NULL, &disklabel_parts },
    115 #endif
    116 #ifdef HAVE_GPT
    117 		{ gpt_parts_check, &gpt_parts },
    118 #endif
    119 #ifdef HAVE_MBR
    120 		{ NULL, &mbr_parts },
    121 #endif
    122 #if RAW_PART != 2	/* "whole disk NetBSD" disklabel variant */
    123 		{ NULL, &only_disklabel_parts },
    124 #endif
    125 	};
    126 
    127 	size_t i, avail;
    128 	const struct disk_partitioning_scheme **out;
    129 	bool *is_available;
    130 	static const size_t all_cnt = __arraycount(all_descs);
    131 
    132 	check_available_binaries();
    133 
    134 #if RAW_PART != 2
    135 	/* generate a variant of disklabel w/o parent scheme */
    136 	only_disklabel_parts = disklabel_parts;
    137 	only_disklabel_parts.name = MSG_parttype_only_disklabel;
    138 	only_disklabel_parts.have_boot_support =
    139 	    have_only_disklabel_boot_support;
    140 #endif
    141 
    142 
    143 	is_available = malloc(all_cnt);
    144 
    145 	for (avail = i = 0; i < all_cnt; i++) {
    146 		is_available[i] = all_descs[i].is_available == NULL
    147 				|| all_descs[i].is_available();
    148 		if (is_available[i])
    149 			avail++;
    150 	}
    151 
    152 	if (avail == 0)
    153 		return;
    154 
    155 	num_available_part_schemes = avail;
    156 	available_part_schemes = malloc(sizeof(*available_part_schemes)
    157 	    * (avail+1));
    158 	if (available_part_schemes == NULL)
    159 		return;
    160 
    161 	for (out = available_part_schemes, i = 0; i < all_cnt; i++) {
    162 		if (!is_available[i])
    163 			continue;
    164 		*out++ = all_descs[i].ps;
    165 	}
    166 	*out = NULL;
    167 
    168 	free(is_available);
    169 }
    170