/* vi: set sw=4 ts=4: */
/*
 * fdisk.c -- Partition table manipulator for Linux.
 *
 * Copyright (C) 1992  A. V. Le Blanc (LeBlanc@mcc.ac.uk)
 * Copyright (C) 2001,2002 Vladimir Oleynik <dzo@simtreas.ru> (initial bb port)
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//config:config FDISK
//config:       bool "fdisk (41 kb)"
//config:       default y
//config:       select PLATFORM_LINUX
//config:       help
//config:       The fdisk utility is used to divide hard disks into one or more
//config:       logical disks, which are generally called partitions. This utility
//config:       can be used to list and edit the set of partitions or BSD style
//config:       'disk slices' that are defined on a hard drive.
//config:
//config:config FDISK_SUPPORT_LARGE_DISKS
//config:       bool "Support over 4GB disks"
//config:       default y
//config:       depends on FDISK
//config:       depends on !LFS   # with LFS no special code is needed
//config:
//config:config FEATURE_FDISK_WRITABLE
//config:       bool "Write support"
//config:       default y
//config:       depends on FDISK
//config:       help
//config:       Enabling this option allows you to create or change a partition table
//config:       and write those changes out to disk. If you leave this option
//config:       disabled, you will only be able to view the partition table.
//config:
//config:config FEATURE_AIX_LABEL
//config:       bool "Support AIX disklabels"
//config:       default n
//config:       depends on FDISK && FEATURE_FDISK_WRITABLE
//config:       help
//config:       Enabling this option allows you to create or change AIX disklabels.
//config:       Most people can safely leave this option disabled.
//config:
//config:config FEATURE_SGI_LABEL
//config:       bool "Support SGI disklabels"
//config:       default n
//config:       depends on FDISK && FEATURE_FDISK_WRITABLE
//config:       help
//config:       Enabling this option allows you to create or change SGI disklabels.
//config:       Most people can safely leave this option disabled.
//config:
//config:config FEATURE_SUN_LABEL
//config:       bool "Support SUN disklabels"
//config:       default n
//config:       depends on FDISK && FEATURE_FDISK_WRITABLE
//config:       help
//config:       Enabling this option allows you to create or change SUN disklabels.
//config:       Most people can safely leave this option disabled.
//config:
//config:config FEATURE_OSF_LABEL
//config:       bool "Support BSD disklabels"
//config:       default n
//config:       depends on FDISK && FEATURE_FDISK_WRITABLE
//config:       help
//config:       Enabling this option allows you to create or change BSD disklabels
//config:       and define and edit BSD disk slices.
//config:
//config:config FEATURE_GPT_LABEL
//config:       bool "Support GPT disklabels"
//config:       default n
//config:       depends on FDISK && FEATURE_FDISK_WRITABLE
//config:       help
//config:       Enabling this option allows you to view GUID Partition Table
//config:       disklabels.
//config:
//config:config FEATURE_FDISK_ADVANCED
//config:       bool "Support expert mode"
//config:       default y
//config:       depends on FDISK && FEATURE_FDISK_WRITABLE
//config:       help
//config:       Enabling this option allows you to do terribly unsafe things like
//config:       define arbitrary drive geometry, move the beginning of data in a
//config:       partition, and similarly evil things. Unless you have a very good
//config:       reason you would be wise to leave this disabled.

//applet:IF_FDISK(APPLET(fdisk, BB_DIR_SBIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_FDISK) += fdisk.o

/* Looks like someone forgot to add this to config system */
//usage:#ifndef ENABLE_FEATURE_FDISK_BLKSIZE
//usage:# define ENABLE_FEATURE_FDISK_BLKSIZE 0
//usage:# define IF_FEATURE_FDISK_BLKSIZE(a)
//usage:#endif
//usage:
//usage:#define fdisk_trivial_usage
//usage:       "[-ul" IF_FEATURE_FDISK_BLKSIZE("s") "] "
//usage:       "[-C CYLINDERS] [-H HEADS] [-S SECTORS] [-b SSZ] DISK"
//usage:#define fdisk_full_usage "\n\n"
//usage:       "Change partition table\n"
//usage:     "\n        -u              Start and End are in sectors (instead of cylinders)"
//usage:     "\n        -l              Show partition table for each DISK, then exit"
//usage:        IF_FEATURE_FDISK_BLKSIZE(
//usage:     "\n        -s              Show partition sizes in kb for each DISK, then exit"
//usage:        )
//usage:     "\n        -b 2048         (for certain MO disks) use 2048-byte sectors"
//usage:     "\n        -C CYLINDERS    Set number of cylinders/heads/sectors"
//usage:     "\n        -H HEADS        Typically 255"
//usage:     "\n        -S SECTORS      Typically 63"

#ifndef _LARGEFILE64_SOURCE
/* For lseek64 */
# define _LARGEFILE64_SOURCE
#endif
#include <assert.h>             /* assert */
#include <sys/mount.h>
#if !defined(BLKSSZGET)
# define BLKSSZGET _IO(0x12, 104)
#endif
#if !defined(BLKGETSIZE64)
# define BLKGETSIZE64 _IOR(0x12,114,size_t)
#endif
#include "libbb.h"
#include "unicode.h"

#if BB_LITTLE_ENDIAN
# define inline_if_little_endian ALWAYS_INLINE
#else
# define inline_if_little_endian /* nothing */
#endif


/* Looks like someone forgot to add this to config system */
#ifndef ENABLE_FEATURE_FDISK_BLKSIZE
# define ENABLE_FEATURE_FDISK_BLKSIZE 0
# define IF_FEATURE_FDISK_BLKSIZE(a)
#endif

#define DEFAULT_SECTOR_SIZE      512
#define DEFAULT_SECTOR_SIZE_STR "512"
#define MAX_SECTOR_SIZE         2048
#define SECTOR_SIZE              512 /* still used in osf/sgi/sun code */
#define MAXIMUM_PARTS             60

#define ACTIVE_FLAG             0x80

#define EXTENDED                0x05
#define WIN98_EXTENDED          0x0f
#define LINUX_PARTITION         0x81
#define LINUX_SWAP              0x82
#define LINUX_NATIVE            0x83
#define LINUX_EXTENDED          0x85
#define LINUX_LVM               0x8e
#define LINUX_RAID              0xfd


enum {
        OPT_b = 1 << 0,
        OPT_C = 1 << 1,
        OPT_H = 1 << 2,
        OPT_l = 1 << 3,
        OPT_S = 1 << 4,
        OPT_u = 1 << 5,
        OPT_s = (1 << 6) * ENABLE_FEATURE_FDISK_BLKSIZE,
};


typedef unsigned long long ullong;
/* Used for sector numbers. Partition formats we know
 * do not support more than 2^32 sectors
 */
typedef uint32_t sector_t;
#if UINT_MAX == 0xffffffff
# define SECT_FMT ""
#elif ULONG_MAX == 0xffffffff
# define SECT_FMT "l"
#else
# error Cant detect sizeof(uint32_t)
#endif

struct hd_geometry {
        unsigned char heads;
        unsigned char sectors;
        unsigned short cylinders;
        unsigned long start;
};

#define HDIO_GETGEO     0x0301  /* get device geometry */

/* TODO: #if ENABLE_FEATURE_FDISK_WRITABLE */
/* (currently fdisk_sun/sgi.c do not have proper WRITABLE #ifs) */
static const char msg_building_new_label[] ALIGN1 =
"Building a new %s. Changes will remain in memory only,\n"
"until you decide to write them. After that the previous content\n"
"won't be recoverable.\n\n";

static const char msg_part_already_defined[] ALIGN1 =
"Partition %u is already defined, delete it before re-adding\n";
/* #endif */


struct partition {
        unsigned char boot_ind;         /* 0x80 - active */
        unsigned char head;             /* starting head */
        unsigned char sector;           /* starting sector */
        unsigned char cyl;              /* starting cylinder */
        unsigned char sys_ind;          /* what partition type */
        unsigned char end_head;         /* end head */
        unsigned char end_sector;       /* end sector */
        unsigned char end_cyl;          /* end cylinder */
        unsigned char start4[4];        /* starting sector counting from 0 */
        unsigned char size4[4];         /* nr of sectors in partition */
} PACKED;

/*
 * per partition table entry data
 *
 * The four primary partitions have the same sectorbuffer (MBRbuffer)
 * and have NULL ext_pointer.
 * Each logical partition table entry has two pointers, one for the
 * partition and one link to the next one.
 */
struct pte {
        struct partition *part_table;   /* points into sectorbuffer */
        struct partition *ext_pointer;  /* points into sectorbuffer */
        sector_t offset_from_dev_start; /* disk sector number */
        char *sectorbuffer;             /* disk sector contents */
#if ENABLE_FEATURE_FDISK_WRITABLE
        char changed;                   /* boolean */
#endif
};

#define unable_to_open "can't open '%s'"
#define unable_to_read "can't read from %s"
#define unable_to_seek "can't seek on %s"

enum label_type {
        LABEL_DOS, LABEL_SUN, LABEL_SGI, LABEL_AIX, LABEL_OSF, LABEL_GPT
};

#define LABEL_IS_DOS    (LABEL_DOS == current_label_type)

#if ENABLE_FEATURE_SUN_LABEL
#define LABEL_IS_SUN    (LABEL_SUN == current_label_type)
#define STATIC_SUN static
#else
#define LABEL_IS_SUN    0
#define STATIC_SUN extern
#endif

#if ENABLE_FEATURE_SGI_LABEL
#define LABEL_IS_SGI    (LABEL_SGI == current_label_type)
#define STATIC_SGI static
#else
#define LABEL_IS_SGI    0
#define STATIC_SGI extern
#endif

#if ENABLE_FEATURE_AIX_LABEL
#define LABEL_IS_AIX    (LABEL_AIX == current_label_type)
#define STATIC_AIX static
#else
#define LABEL_IS_AIX    0
#define STATIC_AIX extern
#endif

#if ENABLE_FEATURE_OSF_LABEL
#define LABEL_IS_OSF    (LABEL_OSF == current_label_type)
#define STATIC_OSF static
#else
#define LABEL_IS_OSF    0
#define STATIC_OSF extern
#endif

#if ENABLE_FEATURE_GPT_LABEL
#define LABEL_IS_GPT    (LABEL_GPT == current_label_type)
#define STATIC_GPT static
#else
#define LABEL_IS_GPT    0
#define STATIC_GPT extern
#endif

enum action { OPEN_MAIN, TRY_ONLY, CREATE_EMPTY_DOS, CREATE_EMPTY_SUN };

static void update_units(void);
#if ENABLE_FEATURE_FDISK_WRITABLE
static void change_units(void);
static void reread_partition_table(int leave);
static void delete_partition(int i);
static unsigned get_partition(int warn, unsigned max);
static void list_types(const char *const *sys);
static sector_t read_int(sector_t low, sector_t dflt, sector_t high, sector_t base, const char *mesg);
#endif
static const char *partition_type(unsigned char type);
static void get_geometry(void);
static void read_pte(struct pte *pe, sector_t offset);
#if ENABLE_FEATURE_SUN_LABEL || ENABLE_FEATURE_FDISK_WRITABLE
static int get_boot(enum action what);
#else
static int get_boot(void);
#endif

#define PLURAL   0
#define SINGULAR 1

static sector_t get_start_sect(const struct partition *p);
static sector_t get_nr_sects(const struct partition *p);

/* DOS partition types */

static const char *const i386_sys_types[] = {
        "\x00" "Empty",
        "\x01" "FAT12",
        "\x04" "FAT16 <32M",
        "\x05" "Extended",         /* DOS 3.3+ extended partition */
        "\x06" "FAT16",            /* DOS 16-bit >=32M */
        "\x07" "HPFS/NTFS",        /* OS/2 IFS, eg, HPFS or NTFS or QNX */
        "\x0a" "OS/2 Boot Manager",/* OS/2 Boot Manager */
        "\x0b" "Win95 FAT32",
        "\x0c" "Win95 FAT32 (LBA)",/* LBA really is 'Extended Int 13h' */
        "\x0e" "Win95 FAT16 (LBA)",
        "\x0f" "Win95 Ext'd (LBA)",
        "\x11" "Hidden FAT12",
        "\x12" "Compaq diagnostics",
        "\x14" "Hidden FAT16 <32M",
        "\x16" "Hidden FAT16",
        "\x17" "Hidden HPFS/NTFS",
        "\x1b" "Hidden Win95 FAT32",
        "\x1c" "Hidden W95 FAT32 (LBA)",
        "\x1e" "Hidden W95 FAT16 (LBA)",
        "\x3c" "Part.Magic recovery",
        "\x41" "PPC PReP Boot",
        "\x42" "SFS",
        "\x63" "GNU HURD or SysV", /* GNU HURD or Mach or Sys V/386 (such as ISC UNIX) */
        "\x80" "Old Minix",        /* Minix 1.4a and earlier */
        "\x81" "Minix / old Linux",/* Minix 1.4b and later */
        "\x82" "Linux swap",       /* also Solaris */
        "\x83" "Linux",
        "\x84" "OS/2 hidden C: drive",
        "\x85" "Linux extended",
        "\x86" "NTFS volume set",
        "\x87" "NTFS volume set",
        "\x8e" "Linux LVM",
        "\x9f" "BSD/OS",           /* BSDI */
        "\xa0" "Thinkpad hibernation",
        "\xa5" "FreeBSD",          /* various BSD flavours */
        "\xa6" "OpenBSD",
        "\xa8" "Darwin UFS",
        "\xa9" "NetBSD",
        "\xab" "Darwin boot",
        "\xb7" "BSDI fs",
        "\xb8" "BSDI swap",
        "\xbe" "Solaris boot",
        "\xeb" "BeOS fs",
        "\xee" "EFI GPT",                    /* Intel EFI GUID Partition Table */
        "\xef" "EFI (FAT-12/16/32)",         /* Intel EFI System Partition */
        "\xf0" "Linux/PA-RISC boot",         /* Linux/PA-RISC boot loader */
        "\xf2" "DOS secondary",              /* DOS 3.3+ secondary */
        "\xfd" "Linux raid autodetect",      /* New (2.2.x) raid partition with
                                                autodetect using persistent
                                                superblock */
#if 0 /* ENABLE_WEIRD_PARTITION_TYPES */
        "\x02" "XENIX root",
        "\x03" "XENIX usr",
        "\x08" "AIX",              /* AIX boot (AIX -- PS/2 port) or SplitDrive */
        "\x09" "AIX bootable",     /* AIX data or Coherent */
        "\x10" "OPUS",
        "\x18" "AST SmartSleep",
        "\x24" "NEC DOS",
        "\x39" "Plan 9",
        "\x40" "Venix 80286",
        "\x4d" "QNX4.x",
        "\x4e" "QNX4.x 2nd part",
        "\x4f" "QNX4.x 3rd part",
        "\x50" "OnTrack DM",
        "\x51" "OnTrack DM6 Aux1", /* (or Novell) */
        "\x52" "CP/M",             /* CP/M or Microport SysV/AT */
        "\x53" "OnTrack DM6 Aux3",
        "\x54" "OnTrackDM6",
        "\x55" "EZ-Drive",
        "\x56" "Golden Bow",
        "\x5c" "Priam Edisk",
        "\x61" "SpeedStor",
        "\x64" "Novell Netware 286",
        "\x65" "Novell Netware 386",
        "\x70" "DiskSecure Multi-Boot",
        "\x75" "PC/IX",
        "\x93" "Amoeba",
        "\x94" "Amoeba BBT",       /* (bad block table) */
        "\xa7" "NeXTSTEP",
        "\xbb" "Boot Wizard hidden",
        "\xc1" "DRDOS/sec (FAT-12)",
        "\xc4" "DRDOS/sec (FAT-16 < 32M)",
        "\xc6" "DRDOS/sec (FAT-16)",
        "\xc7" "Syrinx",
        "\xda" "Non-FS data",
        "\xdb" "CP/M / CTOS / ...",/* CP/M or Concurrent CP/M or
                                      Concurrent DOS or CTOS */
        "\xde" "Dell Utility",     /* Dell PowerEdge Server utilities */
        "\xdf" "BootIt",           /* BootIt EMBRM */
        "\xe1" "DOS access",       /* DOS access or SpeedStor 12-bit FAT
                                      extended partition */
        "\xe3" "DOS R/O",          /* DOS R/O or SpeedStor */
        "\xe4" "SpeedStor",        /* SpeedStor 16-bit FAT extended
                                      partition < 1024 cyl. */
        "\xf1" "SpeedStor",
        "\xf4" "SpeedStor",        /* SpeedStor large partition */
        "\xfe" "LANstep",          /* SpeedStor >1024 cyl. or LANstep */
        "\xff" "BBT",              /* Xenix Bad Block Table */
#endif
        NULL
};

enum {
        dev_fd = 3                  /* the disk */
};

/* Globals */
struct globals {
        char *line_ptr;

        const char *disk_device;
        int g_partitions; // = 4;       /* maximum partition + 1 */
        unsigned units_per_sector; // = 1;
        unsigned sector_size; // = DEFAULT_SECTOR_SIZE;
        unsigned user_set_sector_size;
        unsigned sector_offset; // = 1;
        unsigned g_heads, g_sectors, g_cylinders;
        smallint /* enum label_type */ current_label_type;
        smallint display_in_cyl_units;
#if ENABLE_FEATURE_OSF_LABEL
        smallint possibly_osf_label;
#endif

        smallint listing;               /* no aborts for fdisk -l */
        smallint dos_compatible_flag; // = 1;
#if ENABLE_FEATURE_FDISK_WRITABLE
        //int dos_changed;
        smallint nowarn;                /* no warnings for fdisk -l/-s */
#endif
        int ext_index;                  /* the prime extended partition */
        unsigned user_cylinders, user_heads, user_sectors;
        unsigned pt_heads, pt_sectors;
        unsigned kern_heads, kern_sectors;
        sector_t extended_offset;       /* offset of link pointers */
        sector_t total_number_of_sectors;

        jmp_buf listingbuf;
        char line_buffer[80];
        /* Raw disk label. For DOS-type partition tables the MBR,
         * with descriptions of the primary partitions. */
        char MBRbuffer[MAX_SECTOR_SIZE];
        /* Partition tables */
        struct pte ptes[MAXIMUM_PARTS];
};
#define G (*ptr_to_globals)
#define line_ptr             (G.line_ptr            )
#define disk_device          (G.disk_device         )
#define g_partitions         (G.g_partitions        )
#define units_per_sector     (G.units_per_sector    )
#define sector_size          (G.sector_size         )
#define user_set_sector_size (G.user_set_sector_size)
#define sector_offset        (G.sector_offset       )
#define g_heads              (G.g_heads             )
#define g_sectors            (G.g_sectors           )
#define g_cylinders          (G.g_cylinders         )
#define current_label_type   (G.current_label_type  )
#define display_in_cyl_units (G.display_in_cyl_units)
#define possibly_osf_label   (G.possibly_osf_label  )
#define listing                 (G.listing                )
#define dos_compatible_flag     (G.dos_compatible_flag    )
#define nowarn                  (G.nowarn                 )
#define ext_index               (G.ext_index              )
#define user_cylinders          (G.user_cylinders         )
#define user_heads              (G.user_heads             )
#define user_sectors            (G.user_sectors           )
#define pt_heads                (G.pt_heads               )
#define pt_sectors              (G.pt_sectors             )
#define kern_heads              (G.kern_heads             )
#define kern_sectors            (G.kern_sectors           )
#define extended_offset         (G.extended_offset        )
#define total_number_of_sectors (G.total_number_of_sectors)
#define listingbuf      (G.listingbuf     )
#define line_buffer     (G.line_buffer    )
#define MBRbuffer       (G.MBRbuffer      )
#define ptes            (G.ptes           )
#define INIT_G() do { \
        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
        sector_size = DEFAULT_SECTOR_SIZE; \
        sector_offset = 1; \
        g_partitions = 4; \
        units_per_sector = 1; \
        dos_compatible_flag = 1; \
} while (0)


/* TODO: move to libbb? */
/* TODO: return unsigned long long, FEATURE_FDISK_BLKSIZE _can_ handle
 * disks > 2^32 sectors
 */
static sector_t bb_BLKGETSIZE_sectors(int fd)
{
        uint64_t v64;
        unsigned long longsectors;

        if (ioctl(fd, BLKGETSIZE64, &v64) == 0) {
                /* Got bytes, convert to 512 byte sectors */
                v64 >>= 9;
                if (v64 != (sector_t)v64) {
 ret_trunc:
                        /* Not only DOS, but all other partition tables
                         * we support can't record more than 32 bit
                         * sector counts or offsets
                         */
                        bb_error_msg("device has more than 2^32 sectors, can't use all of them");
                        v64 = (uint32_t)-1L;
                }
                return v64;
        }
        /* Needs temp of type long */
        if (ioctl(fd, BLKGETSIZE, &longsectors)) {
                /* Perhaps this is a disk image */
                off_t sz = lseek(fd, 0, SEEK_END);
                longsectors = 0;
                if (sz > 0)
                        longsectors = (uoff_t)sz / sector_size;
                lseek(fd, 0, SEEK_SET);
        }
        if (sizeof(long) > sizeof(sector_t)
         && longsectors != (sector_t)longsectors
        ) {
                goto ret_trunc;
        }
        return longsectors;
}


#define IS_EXTENDED(i) \
        ((i) == EXTENDED || (i) == WIN98_EXTENDED || (i) == LINUX_EXTENDED)

#define cround(n)       (display_in_cyl_units ? ((n)/units_per_sector)+1 : (n))

#define scround(x)      (((x)+units_per_sector-1)/units_per_sector)

#define pt_offset(b, n) \
        ((struct partition *)((b) + 0x1be + (n) * sizeof(struct partition)))

#define sector(s)       ((s) & 0x3f)

#define cylinder(s, c)  ((c) | (((s) & 0xc0) << 2))

static void
close_dev_fd(void)
{
        /* Not really closing, but making sure it is open, and to harmless place */
        xmove_fd(xopen(bb_dev_null, O_RDONLY), dev_fd);
}

/* Return partition name */
static const char *
partname(const char *dev, int pno, int lth)
{
        const char *p;
        int w, wp;
        int bufsiz;
        char *bufp;

        bufp = auto_string(xzalloc(80));
        bufsiz = 80;

        w = strlen(dev);
        p = "";

        if (isdigit(dev[w-1]))
                p = "p";

        /* devfs kludge - note: fdisk partition names are not supposed
           to equal kernel names, so there is no reason to do this */
        if (strcmp(dev + w - 4, "disc") == 0) {
                w -= 4;
                p = "part";
        }

        wp = strlen(p);

        if (lth) {
                snprintf(bufp, bufsiz, "%*.*s%s%-2u",
                        lth-wp-2, w, dev, p, pno);
        } else {
                snprintf(bufp, bufsiz, "%.*s%s%-2u", w, dev, p, pno);
        }
        return bufp;
}

static ALWAYS_INLINE struct partition *
get_part_table(int i)
{
        return ptes[i].part_table;
}

static const char *
str_units(int n)
{      /* n==1: use singular */
        if (n == 1)
                return display_in_cyl_units ? "cylinder" : "sector";
        return display_in_cyl_units ? "cylinders" : "sectors";
}

static int
valid_part_table_flag(const char *mbuffer)
{
        return (mbuffer[510] == 0x55 && (uint8_t)mbuffer[511] == 0xaa);
}

static void fdisk_fatal(const char *why)
{
        if (listing) {
                close_dev_fd();
                longjmp(listingbuf, 1);
        }
        bb_error_msg_and_die(why, disk_device);
}

static void
seek_sector(sector_t secno)
{
#if ENABLE_FDISK_SUPPORT_LARGE_DISKS
        off64_t off = (off64_t)secno * sector_size;
        if (lseek64(dev_fd, off, SEEK_SET) == (off64_t) -1)
                fdisk_fatal(unable_to_seek);
#else
        uint64_t off = (uint64_t)secno * sector_size;
        if (off > MAXINT(off_t)
         || lseek(dev_fd, (off_t)off, SEEK_SET) == (off_t) -1
        ) {
                fdisk_fatal(unable_to_seek);
        }
#endif
}

#if ENABLE_FEATURE_FDISK_WRITABLE
static void
set_all_unchanged(void)
{
        int i;

        for (i = 0; i < MAXIMUM_PARTS; i++)
                ptes[i].changed = 0;
}

static ALWAYS_INLINE void
set_changed(int i)
{
        ptes[i].changed = 1;
}

static ALWAYS_INLINE void
write_part_table_flag(char *b)
{
        b[510] = 0x55;
        b[511] = 0xaa;
}

/* Read line; return 0 or first printable non-space char */
static int
read_line(const char *prompt)
{
        int sz;

        sz = read_line_input(NULL, prompt, line_buffer, sizeof(line_buffer));
        if (sz <= 0)
                exit(EXIT_SUCCESS); /* Ctrl-D or Ctrl-C */

        if (line_buffer[sz-1] == '\n')
                line_buffer[--sz] = '\0';

        line_ptr = line_buffer;
        while (*line_ptr != '\0' && (unsigned char)*line_ptr <= ' ')
                line_ptr++;
        return *line_ptr;
}

static char
read_nonempty(const char *mesg)
{
        while (!read_line(mesg))
                continue;
        return *line_ptr;
}

static char
read_maybe_empty(const char *mesg)
{
        if (!read_line(mesg)) {
                line_ptr = line_buffer;
                line_ptr[0] = '\n';
                line_ptr[1] = '\0';
        }
        return line_ptr[0];
}

static int
read_hex(const char *const *sys)
{
        unsigned long v;
        while (1) {
                read_nonempty("Hex code (type L to list codes): ");
                if ((line_ptr[0] | 0x20) == 'l') {
                        list_types(sys);
                        continue;
                }
                v = bb_strtoul(line_ptr, NULL, 16);
                if (v <= 0xff)
                        return v;
        }
}

static void
write_sector(sector_t secno, const void *buf)
{
        seek_sector(secno);
        xwrite(dev_fd, buf, sector_size);
}
#endif /* FEATURE_FDISK_WRITABLE */


#include "fdisk_aix.c"

struct sun_partition {
        unsigned char info[128];   /* Informative text string */
        unsigned char spare0[14];
        struct sun_info {
                unsigned char spare1;
                unsigned char id;
                unsigned char spare2;
                unsigned char flags;
        } infos[8];
        unsigned char spare1[246]; /* Boot information etc. */
        unsigned short rspeed;     /* Disk rotational speed */
        unsigned short pcylcount;  /* Physical cylinder count */
        unsigned short sparecyl;   /* extra sects per cylinder */
        unsigned char spare2[4];   /* More magic... */
        unsigned short ilfact;     /* Interleave factor */
        unsigned short ncyl;       /* Data cylinder count */
        unsigned short nacyl;      /* Alt. cylinder count */
        unsigned short ntrks;      /* Tracks per cylinder */
        unsigned short nsect;      /* Sectors per track */
        unsigned char spare3[4];   /* Even more magic... */
        struct sun_partinfo {
                uint32_t start_cylinder;
                uint32_t num_sectors;
        } partitions[8];
        unsigned short magic;      /* Magic number */
        unsigned short csum;       /* Label xor'd checksum */
} FIX_ALIASING;
typedef struct sun_partition sun_partition;
#define sunlabel ((sun_partition *)MBRbuffer)
STATIC_OSF void bsd_select(void);
STATIC_OSF void xbsd_print_disklabel(int);
#include "fdisk_osf.c"

STATIC_GPT void gpt_list_table(int xtra);
#include "fdisk_gpt.c"

#if ENABLE_FEATURE_SGI_LABEL || ENABLE_FEATURE_SUN_LABEL
static uint16_t
fdisk_swap16(uint16_t x)
{
        return (x << 8) | (x >> 8);
}

static uint32_t
fdisk_swap32(uint32_t x)
{
        return (x << 24) |
               ((x & 0xFF00) << 8) |
               ((x & 0xFF0000) >> 8) |
               (x >> 24);
}
#endif

STATIC_SGI const char *const sgi_sys_types[];
STATIC_SGI unsigned sgi_get_num_sectors(int i);
STATIC_SGI int sgi_get_sysid(int i);
STATIC_SGI void sgi_delete_partition(int i);
STATIC_SGI void sgi_change_sysid(int i, int sys);
STATIC_SGI void sgi_list_table(int xtra);
#if ENABLE_FEATURE_FDISK_ADVANCED
STATIC_SGI void sgi_set_xcyl(void);
#endif
STATIC_SGI int verify_sgi(int verbose);
STATIC_SGI void sgi_add_partition(int n, int sys);
STATIC_SGI void sgi_set_swappartition(int i);
STATIC_SGI const char *sgi_get_bootfile(void);
STATIC_SGI void sgi_set_bootfile(const char* aFile);
STATIC_SGI void create_sgiinfo(void);
STATIC_SGI void sgi_write_table(void);
STATIC_SGI void sgi_set_bootpartition(int i);
#include "fdisk_sgi.c"

STATIC_SUN const char *const sun_sys_types[];
STATIC_SUN void sun_delete_partition(int i);
STATIC_SUN void sun_change_sysid(int i, int sys);
STATIC_SUN void sun_list_table(int xtra);
STATIC_SUN void add_sun_partition(int n, int sys);
#if ENABLE_FEATURE_FDISK_ADVANCED
STATIC_SUN void sun_set_alt_cyl(void);
STATIC_SUN void sun_set_ncyl(int cyl);
STATIC_SUN void sun_set_xcyl(void);
STATIC_SUN void sun_set_ilfact(void);
STATIC_SUN void sun_set_rspeed(void);
STATIC_SUN void sun_set_pcylcount(void);
#endif
STATIC_SUN void toggle_sunflags(int i, unsigned char mask);
STATIC_SUN void verify_sun(void);
STATIC_SUN void sun_write_table(void);
#include "fdisk_sun.c"


static inline_if_little_endian unsigned
read4_little_endian(const unsigned char *cp)
{
        uint32_t v;
        move_from_unaligned32(v, cp);
        return SWAP_LE32(v);
}

static sector_t
get_start_sect(const struct partition *p)
{
        return read4_little_endian(p->start4);
}

static sector_t
get_nr_sects(const struct partition *p)
{
        return read4_little_endian(p->size4);
}

#if ENABLE_FEATURE_FDISK_WRITABLE
/* start_sect and nr_sects are stored little endian on all machines */
/* moreover, they are not aligned correctly */
static inline_if_little_endian void
store4_little_endian(unsigned char *cp, unsigned val)
{
        uint32_t v = SWAP_LE32(val);
        move_to_unaligned32(cp, v);
}

static void
set_start_sect(struct partition *p, unsigned start_sect)
{
        store4_little_endian(p->start4, start_sect);
}

static void
set_nr_sects(struct partition *p, unsigned nr_sects)
{
        store4_little_endian(p->size4, nr_sects);
}
#endif

/* Allocate a buffer and read a partition table sector */
static void
read_pte(struct pte *pe, sector_t offset)
{
        pe->offset_from_dev_start = offset;
        pe->sectorbuffer = xzalloc(sector_size);
        seek_sector(offset);
        /* xread would make us abort - bad for fdisk -l */
        if (full_read(dev_fd, pe->sectorbuffer, sector_size) != sector_size)
                fdisk_fatal(unable_to_read);
#if ENABLE_FEATURE_FDISK_WRITABLE
        pe->changed = 0;
#endif
        pe->part_table = pe->ext_pointer = NULL;
}

static sector_t
get_partition_start_from_dev_start(const struct pte *pe)
{
        return pe->offset_from_dev_start + get_start_sect(pe->part_table);
}

#if ENABLE_FEATURE_FDISK_WRITABLE
/*
 * Avoid warning about DOS partitions when no DOS partition was changed.
 * Here a heuristic "is probably dos partition".
 * We might also do the opposite and warn in all cases except
 * for "is probably nondos partition".
 */
#ifdef UNUSED
static int
is_dos_partition(int t)
{
        return (t == 1 || t == 4 || t == 6 ||
                t == 0x0b || t == 0x0c || t == 0x0e ||
                t == 0x11 || t == 0x12 || t == 0x14 || t == 0x16 ||
                t == 0x1b || t == 0x1c || t == 0x1e || t == 0x24 ||
                t == 0xc1 || t == 0xc4 || t == 0xc6);
}
#endif

static void
menu(void)
{
        puts("Command Action");
        if (LABEL_IS_SUN) {
                puts("a\ttoggle a read only flag");           /* sun */
                puts("b\tedit bsd disklabel");
                puts("c\ttoggle the mountable flag");         /* sun */
                puts("d\tdelete a partition");
                puts("l\tlist known partition types");
                puts("n\tadd a new partition");
                puts("o\tcreate a new empty DOS partition table");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("s\tcreate a new empty Sun disklabel");  /* sun */
                puts("t\tchange a partition's system id");
                puts("u\tchange display/entry units");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
#if ENABLE_FEATURE_FDISK_ADVANCED
                puts("x\textra functionality (experts only)");
#endif
        } else if (LABEL_IS_SGI) {
                puts("a\tselect bootable partition");    /* sgi flavour */
                puts("b\tedit bootfile entry");          /* sgi */
                puts("c\tselect sgi swap partition");    /* sgi flavour */
                puts("d\tdelete a partition");
                puts("l\tlist known partition types");
                puts("n\tadd a new partition");
                puts("o\tcreate a new empty DOS partition table");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("s\tcreate a new empty Sun disklabel");  /* sun */
                puts("t\tchange a partition's system id");
                puts("u\tchange display/entry units");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
        } else if (LABEL_IS_AIX) {
                puts("o\tcreate a new empty DOS partition table");
                puts("q\tquit without saving changes");
                puts("s\tcreate a new empty Sun disklabel");  /* sun */
        } else if (LABEL_IS_GPT) {
                puts("o\tcreate a new empty DOS partition table");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("s\tcreate a new empty Sun disklabel");  /* sun */
        } else {
                puts("a\ttoggle a bootable flag");
                puts("b\tedit bsd disklabel");
                puts("c\ttoggle the dos compatibility flag");
                puts("d\tdelete a partition");
                puts("l\tlist known partition types");
                puts("n\tadd a new partition");
                puts("o\tcreate a new empty DOS partition table");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("s\tcreate a new empty Sun disklabel");  /* sun */
                puts("t\tchange a partition's system id");
                puts("u\tchange display/entry units");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
#if ENABLE_FEATURE_FDISK_ADVANCED
                puts("x\textra functionality (experts only)");
#endif
        }
}
#endif /* FEATURE_FDISK_WRITABLE */


#if ENABLE_FEATURE_FDISK_ADVANCED
static void
xmenu(void)
{
        puts("Command Action");
        if (LABEL_IS_SUN) {
                puts("a\tchange number of alternate cylinders");      /*sun*/
                puts("c\tchange number of cylinders");
                puts("d\tprint the raw data in the partition table");
                puts("e\tchange number of extra sectors per cylinder");/*sun*/
                puts("h\tchange number of heads");
                puts("i\tchange interleave factor");                  /*sun*/
                puts("o\tchange rotation speed (rpm)");               /*sun*/
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("r\treturn to main menu");
                puts("s\tchange number of sectors/track");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
                puts("y\tchange number of physical cylinders");       /*sun*/
        } else if (LABEL_IS_SGI) {
                puts("b\tmove beginning of data in a partition"); /* !sun */
                puts("c\tchange number of cylinders");
                puts("d\tprint the raw data in the partition table");
                puts("e\tlist extended partitions");          /* !sun */
                puts("g\tcreate an IRIX (SGI) partition table");/* sgi */
                puts("h\tchange number of heads");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");

                puts("r\treturn to main menu");
                puts("s\tchange number of sectors/track");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
        } else if (LABEL_IS_AIX) {
                puts("b\tmove beginning of data in a partition"); /* !sun */
                puts("c\tchange number of cylinders");
                puts("d\tprint the raw data in the partition table");
                puts("e\tlist extended partitions");          /* !sun */
                puts("g\tcreate an IRIX (SGI) partition table");/* sgi */
                puts("h\tchange number of heads");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("r\treturn to main menu");
                puts("s\tchange number of sectors/track");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
        } else {
                puts("b\tmove beginning of data in a partition"); /* !sun */
                puts("c\tchange number of cylinders");
                puts("d\tprint the raw data in the partition table");
                puts("e\tlist extended partitions");          /* !sun */
                puts("f\tfix partition order");               /* !sun, !aix, !sgi */
#if ENABLE_FEATURE_SGI_LABEL
                puts("g\tcreate an IRIX (SGI) partition table");/* sgi */
#endif
                puts("h\tchange number of heads");
                puts("p\tprint the partition table");
                puts("q\tquit without saving changes");
                puts("r\treturn to main menu");
                puts("s\tchange number of sectors/track");
                puts("v\tverify the partition table");
                puts("w\twrite table to disk and exit");
        }
}
#endif /* ADVANCED mode */

#if ENABLE_FEATURE_FDISK_WRITABLE
static const char *const *
get_sys_types(void)
{
        return (
                LABEL_IS_SUN ? sun_sys_types :
                LABEL_IS_SGI ? sgi_sys_types :
                i386_sys_types);
}
#else
#define get_sys_types() i386_sys_types
#endif

static const char *
partition_type(unsigned char type)
{
        int i;
        const char *const *types = get_sys_types();

        for (i = 0; types[i]; i++)
                if ((unsigned char)types[i][0] == type)
                        return types[i] + 1;

        return "Unknown";
}

static int
is_cleared_partition(const struct partition *p)
{
        /* We consider partition "cleared" only if it has only zeros */
        const char *cp = (const char *)p;
        int cnt = sizeof(*p);
        char bits = 0;
        while (--cnt >= 0)
                bits |= *cp++;
        return (bits == 0);
}

static void
clear_partition(struct partition *p)
{
        if (p)
                memset(p, 0, sizeof(*p));
}

#if ENABLE_FEATURE_FDISK_WRITABLE
static int
get_sysid(int i)
{
        return LABEL_IS_SUN ? sunlabel->infos[i].id :
                        (LABEL_IS_SGI ? sgi_get_sysid(i) :
                                ptes[i].part_table->sys_ind);
}

static void
list_types(const char *const *sys)
{
        enum { COLS = 3 };

        unsigned last[COLS];
        unsigned done, next, size;
        int i;

        for (size = 0; sys[size]; size++)
                continue;

        done = 0;
        for (i = COLS-1; i >= 0; i--) {
                done += (size + i - done) / (i + 1);
                last[COLS-1 - i] = done;
        }

        i = done = next = 0;
        do {
                printf("%c%2x %-22.22s", i ? ' ' : '\n',
                        (unsigned char)sys[next][0],
                        sys[next] + 1);
                next = last[i++] + done;
                if (i >= COLS || next >= last[i]) {
                        i = 0;
                        next = ++done;
                }
        } while (done < last[0]);
        bb_putchar('\n');
}

#define set_hsc(h, s, c, sector) do \
{ \
        s = sector % g_sectors + 1;  \
        sector /= g_sectors;         \
        h = sector % g_heads;        \
        sector /= g_heads;           \
        c = sector & 0xff;           \
        s |= (sector >> 2) & 0xc0;   \
} while (0)

static void set_hsc_start_end(struct partition *p, sector_t start, sector_t stop)
{
        if (dos_compatible_flag && (start / (g_sectors * g_heads) > 1023))
                start = g_heads * g_sectors * 1024 - 1;
        set_hsc(p->head, p->sector, p->cyl, start);

        if (dos_compatible_flag && (stop / (g_sectors * g_heads) > 1023))
                stop = g_heads * g_sectors * 1024 - 1;
        set_hsc(p->end_head, p->end_sector, p->end_cyl, stop);
}

static void
set_partition(int i, int doext, sector_t start, sector_t stop, int sysid)
{
        struct partition *p;
        sector_t offset;

        if (doext) {
                p = ptes[i].ext_pointer;
                offset = extended_offset;
        } else {
                p = ptes[i].part_table;
                offset = ptes[i].offset_from_dev_start;
        }
        p->boot_ind = 0;
        p->sys_ind = sysid;
        set_start_sect(p, start - offset);
        set_nr_sects(p, stop - start + 1);
        set_hsc_start_end(p, start, stop);
        ptes[i].changed = 1;
}
#endif

static int
warn_geometry(void)
{
        if (g_heads && g_sectors && g_cylinders)
                return 0;

        printf("Unknown value(s) for:");
        if (!g_heads)
                printf(" heads");
        if (!g_sectors)
                printf(" sectors");
        if (!g_cylinders)
                printf(" cylinders");
#if ENABLE_FEATURE_FDISK_WRITABLE
        puts(" (settable in the extra functions menu)");
#else
        bb_putchar('\n');
#endif
        return 1;
}

static void
update_units(void)
{
        int cyl_units = g_heads * g_sectors;

        if (display_in_cyl_units && cyl_units)
                units_per_sector = cyl_units;
        else
                units_per_sector = 1;   /* in sectors */
}

#if ENABLE_FEATURE_FDISK_WRITABLE
static void
warn_cylinders(void)
{
        if (LABEL_IS_DOS && g_cylinders > 1024 && !nowarn)
                printf("\n"
"The number of cylinders for this disk is set to %u.\n"
"There is nothing wrong with that, but this is larger than 1024,\n"
"and could in certain setups cause problems with:\n"
"1) software that runs at boot time (e.g., old versions of LILO)\n"
"2) booting and partitioning software from other OSs\n"
"   (e.g., DOS FDISK, OS/2 FDISK)\n",
                        g_cylinders);
}
#endif

static void
read_extended(int ext)
{
        int i;
        struct pte *pex;
        struct partition *p, *q;

        ext_index = ext;
        pex = &ptes[ext];
        pex->ext_pointer = pex->part_table;

        p = pex->part_table;
        if (!get_start_sect(p)) {
                puts("Bad offset in primary extended partition");
                return;
        }

        while (IS_EXTENDED(p->sys_ind)) {
                struct pte *pe = &ptes[g_partitions];

                if (g_partitions >= MAXIMUM_PARTS) {
                        /* This is not a Linux restriction, but
                           this program uses arrays of size MAXIMUM_PARTS.
                           Do not try to 'improve' this test. */
                        struct pte *pre = &ptes[g_partitions - 1];
#if ENABLE_FEATURE_FDISK_WRITABLE
                        printf("Warning: deleting partitions after %u\n",
                                g_partitions);
                        pre->changed = 1;
#endif
                        clear_partition(pre->ext_pointer);
                        return;
                }

                read_pte(pe, extended_offset + get_start_sect(p));

                if (!extended_offset)
                        extended_offset = get_start_sect(p);

                q = p = pt_offset(pe->sectorbuffer, 0);
                for (i = 0; i < 4; i++, p++) if (get_nr_sects(p)) {
                        if (IS_EXTENDED(p->sys_ind)) {
                                if (pe->ext_pointer)
                                        printf("Warning: extra link "
                                                "pointer in partition table"
                                                " %u\n", g_partitions + 1);
                                else
                                        pe->ext_pointer = p;
                        } else if (p->sys_ind) {
                                if (pe->part_table)
                                        printf("Warning: ignoring extra "
                                                  "data in partition table"
                                                  " %u\n", g_partitions + 1);
                                else
                                        pe->part_table = p;
                        }
                }

                /* very strange code here... */
                if (!pe->part_table) {
                        if (q != pe->ext_pointer)
                                pe->part_table = q;
                        else
                                pe->part_table = q + 1;
                }
                if (!pe->ext_pointer) {
                        if (q != pe->part_table)
                                pe->ext_pointer = q;
                        else
                                pe->ext_pointer = q + 1;
                }

                p = pe->ext_pointer;
                g_partitions++;
        }

#if ENABLE_FEATURE_FDISK_WRITABLE
        /* remove empty links */
 remove:
        for (i = 4; i < g_partitions; i++) {
                struct pte *pe = &ptes[i];

                if (!get_nr_sects(pe->part_table)
                 && (g_partitions > 5 || ptes[4].part_table->sys_ind)
                ) {
                        printf("Omitting empty partition (%u)\n", i+1);
                        delete_partition(i);
                        goto remove;    /* numbering changed */
                }
        }
#endif
}

#if ENABLE_FEATURE_FDISK_WRITABLE
static void
create_doslabel(void)
{
        printf(msg_building_new_label, "DOS disklabel");

        current_label_type = LABEL_DOS;
#if ENABLE_FEATURE_OSF_LABEL
        possibly_osf_label = 0;
#endif
        g_partitions = 4;

        memset(&MBRbuffer[510 - 4*16], 0, 4*16);
        write_part_table_flag(MBRbuffer);
        extended_offset = 0;
        set_all_unchanged();
        set_changed(0);
        get_boot(CREATE_EMPTY_DOS);
}
#endif

static void
get_sectorsize(void)
{
        if (!user_set_sector_size) {
                int arg;
                if (ioctl(dev_fd, BLKSSZGET, &arg) == 0)
                        sector_size = arg;
                if (sector_size != DEFAULT_SECTOR_SIZE)
                        printf("Note: sector size is %u "
                                "(not " DEFAULT_SECTOR_SIZE_STR ")\n",
                                sector_size);
        }
}

static void
get_kernel_geometry(void)
{
        struct hd_geometry geometry;

        if (!ioctl(dev_fd, HDIO_GETGEO, &geometry)) {
                kern_heads = geometry.heads;
                kern_sectors = geometry.sectors;
                /* never use geometry.cylinders - it is truncated */
        }
}

static void
get_partition_table_geometry(void)
{
        const unsigned char *bufp = (const unsigned char *)MBRbuffer;
        struct partition *p;
        int i, h, s, hh, ss;
        int first = 1;
        int bad = 0;

        if (!(valid_part_table_flag((char*)bufp)))
                return;

        hh = ss = 0;
        for (i = 0; i < 4; i++) {
                p = pt_offset(bufp, i);
                if (p->sys_ind != 0) {
                        h = p->end_head + 1;
                        s = (p->end_sector & 077);
                        if (first) {
                                hh = h;
                                ss = s;
                                first = 0;
                        } else if (hh != h || ss != s)
                                bad = 1;
                }
        }

        if (!first && !bad) {
                pt_heads = hh;
                pt_sectors = ss;
        }
}

static void
get_geometry(void)
{
        int sec_fac;

        get_sectorsize();
        sec_fac = sector_size / 512;
#if ENABLE_FEATURE_SUN_LABEL
        guess_device_type();
#endif
        g_heads = g_cylinders = g_sectors = 0;
        kern_heads = kern_sectors = 0;
        pt_heads = pt_sectors = 0;

        get_kernel_geometry();
        get_partition_table_geometry();

        g_heads = user_heads ? user_heads :
                pt_heads ? pt_heads :
                kern_heads ? kern_heads : 255;
        g_sectors = user_sectors ? user_sectors :
                pt_sectors ? pt_sectors :
                kern_sectors ? kern_sectors : 63;
        total_number_of_sectors = bb_BLKGETSIZE_sectors(dev_fd);

        sector_offset = 1;
        if (dos_compatible_flag)
                sector_offset = g_sectors;

        g_cylinders = total_number_of_sectors / (g_heads * g_sectors * sec_fac);
        if (!g_cylinders)
                g_cylinders = user_cylinders;
}

/*
 * Opens disk_device and optionally reads MBR.
 *    If what == OPEN_MAIN:
 *      Open device, read MBR.  Abort program on short read.  Create empty
 *      disklabel if the on-disk structure is invalid (WRITABLE mode).
 *    If what == TRY_ONLY:
 *      Open device, read MBR.  Return an error if anything is out of place.
 *      Do not create an empty disklabel.  This is used for the "list"
 *      operations: "fdisk -l /dev/sda" and "fdisk -l" (all devices).
 *    If what == CREATE_EMPTY_*:
 *      This means that get_boot() was called recursively from create_*label().
 *      Do not re-open the device; just set up the ptes array and print
 *      geometry warnings.
 *
 * Returns:
 *   -1: no 0xaa55 flag present (possibly entire disk BSD)
 *    0: found or created label
 *    1: I/O error
 */
#if ENABLE_FEATURE_SUN_LABEL || ENABLE_FEATURE_FDISK_WRITABLE
static int get_boot(enum action what)
#else
static int get_boot(void)
#define get_boot(what) get_boot()
#endif
{
        int i, fd;

        g_partitions = 4;
        for (i = 0; i < 4; i++) {
                struct pte *pe = &ptes[i];
                pe->part_table = pt_offset(MBRbuffer, i);
                pe->ext_pointer = NULL;
                pe->offset_from_dev_start = 0;
                pe->sectorbuffer = MBRbuffer;
#if ENABLE_FEATURE_FDISK_WRITABLE
                pe->changed = (what == CREATE_EMPTY_DOS);
#endif
        }

#if ENABLE_FEATURE_FDISK_WRITABLE
// ALERT! highly idiotic design!
// We end up here when we call get_boot() recursively
// via get_boot() [table is bad] -> create_doslabel() -> get_boot(CREATE_EMPTY_DOS).
// or get_boot() [table is bad] -> create_sunlabel() -> get_boot(CREATE_EMPTY_SUN).
// (just factor out re-init of ptes[0,1,2,3] in a separate fn instead?)
// So skip opening device _again_...
        if (what == CREATE_EMPTY_DOS  IF_FEATURE_SUN_LABEL(|| what == CREATE_EMPTY_SUN))
                goto created_table;

        fd = open(disk_device, (option_mask32 & OPT_l) ? O_RDONLY : O_RDWR);

        if (fd < 0) {
                fd = open(disk_device, O_RDONLY);
                if (fd < 0) {
                        if (what == TRY_ONLY)
                                return 1;
                        fdisk_fatal(unable_to_open);
                }
                printf("'%s' is opened for read only\n", disk_device);
        }
        xmove_fd(fd, dev_fd);
        if (512 != full_read(dev_fd, MBRbuffer, 512)) {
                if (what == TRY_ONLY) {
                        close_dev_fd();
                        return 1;
                }
                fdisk_fatal(unable_to_read);
        }
#else
        fd = open(disk_device, O_RDONLY);
        if (fd < 0)
                return 1;
        if (512 != full_read(fd, MBRbuffer, 512)) {
                close(fd);
                return 1;
        }
        xmove_fd(fd, dev_fd);
#endif

        get_geometry();
        update_units();

#if ENABLE_FEATURE_SUN_LABEL
        if (check_sun_label())
                return 0;
#endif
#if ENABLE_FEATURE_SGI_LABEL
        if (check_sgi_label())
                return 0;
#endif
#if ENABLE_FEATURE_AIX_LABEL
        if (check_aix_label())
                return 0;
#endif
#if ENABLE_FEATURE_GPT_LABEL
        if (check_gpt_label())
                return 0;
#endif
#if ENABLE_FEATURE_OSF_LABEL
        if (check_osf_label()) {
                possibly_osf_label = 1;
                if (!valid_part_table_flag(MBRbuffer)) {
                        current_label_type = LABEL_OSF;
                        return 0;
                }
                puts("This disk has both DOS and BSD magic.\n"
                     "Give the 'b' command to go to BSD mode.");
        }
#endif

#if !ENABLE_FEATURE_FDISK_WRITABLE
        if (!valid_part_table_flag(MBRbuffer))
                return -1;
#else
        if (!valid_part_table_flag(MBRbuffer)) {
                if (what == OPEN_MAIN) {
                        puts("Device contains neither a valid DOS "
                             "partition table, nor Sun, SGI, OSF or GPT "
                             "disklabel");
#ifdef __sparc__
                        IF_FEATURE_SUN_LABEL(create_sunlabel();)
#else
                        create_doslabel();
#endif
                        return 0;
                }
                /* TRY_ONLY: */
                return -1;
        }
 created_table:
#endif /* FEATURE_FDISK_WRITABLE */


        IF_FEATURE_FDISK_WRITABLE(warn_cylinders();)
        warn_geometry();

        for (i = 0; i < 4; i++) {
                if (IS_EXTENDED(ptes[i].part_table->sys_ind)) {
                        if (g_partitions != 4)
                                printf("Ignoring extra extended "
                                        "partition %u\n", i + 1);
                        else
                                read_extended(i);
                }
        }

        for (i = 3; i < g_partitions; i++) {
                struct pte *pe = &ptes[i];
                if (!valid_part_table_flag(pe->sectorbuffer)) {
                        printf("Warning: invalid flag 0x%02x,0x%02x of partition "
                                "table %u will be corrected by w(rite)\n",
                                pe->sectorbuffer[510],
                                pe->sectorbuffer[511],
                                i + 1);
                        IF_FEATURE_FDISK_WRITABLE(pe->changed = 1;)
                }
        }

        return 0;
}

#if ENABLE_FEATURE_FDISK_WRITABLE
/*
 * Print the message MESG, then read an integer between LOW and HIGH (inclusive).
 * If the user hits Enter, DFLT is returned.
 * Answers like +10 are interpreted as offsets from BASE.
 *
 * There is no default if DFLT is not between LOW and HIGH.
 */
static sector_t
read_int(sector_t low, sector_t dflt, sector_t high, sector_t base, const char *mesg)
{
        sector_t value;
        int default_ok = 1;
        const char *fmt = "%s (%u-%u, default %u): ";

        if (dflt < low || dflt > high) {
                fmt = "%s (%u-%u): ";
                default_ok = 0;
        }

        while (1) {
                int use_default = default_ok;

                /* ask question and read answer */
                do {
                        printf(fmt, mesg, low, high, dflt);
                        read_maybe_empty("");
                } while (*line_ptr != '\n' && !isdigit(*line_ptr)
                 && *line_ptr != '-' && *line_ptr != '+');

                if (*line_ptr == '+' || *line_ptr == '-') {
                        int minus = (*line_ptr == '-');
                        unsigned scale_shift;

                        if (sizeof(value) <= sizeof(long))
                                value = strtoul(line_ptr + 1, NULL, 10);
                        else
                                value = strtoull(line_ptr + 1, NULL, 10);

                        /* (1) if 2nd char is digit, use_default = 0.
                         * (2) move line_ptr to first non-digit.
                         */
                        while (isdigit(*++line_ptr))
                                use_default = 0;

                        scale_shift = 0;
                        switch (*line_ptr | 0x20) {
                        case 'k':
                                scale_shift = 10; /* 1024 */
                                break;
                        case 'm':
                                scale_shift = 20; /* 1024*1024 */
                                break;
                        case 'g':
                                scale_shift = 30; /* 1024*1024*1024 */
                                break;
                        case 't':
                                scale_shift = 40; /* 1024*1024*1024*1024 */
                                break;
                        default:
                                break;
                        }
                        if (scale_shift) {
                                ullong bytes;
                                unsigned long unit;

                                bytes = (ullong) value << scale_shift;
                                unit = sector_size * units_per_sector;
                                bytes += unit/2; /* round */
                                bytes /= unit;
                                value = (bytes != 0 ? bytes - 1 : 0);
                        }
                        if (minus)
                                value = -value;
                        value += base;
                } else {
                        if (sizeof(value) <= sizeof(long))
                                value = strtoul(line_ptr, NULL, 10);
                        else
                                value = strtoull(line_ptr, NULL, 10);
                        while (isdigit(*line_ptr)) {
                                line_ptr++;
                                use_default = 0;
                        }
                }
                if (use_default) {
                        value = dflt;
                        printf("Using default value %u\n", value);
                }
                if (value >= low && value <= high)
                        break;
                puts("Value is out of range");
        }
        return value;
}

static unsigned
get_partition(int warn, unsigned max)
{
        struct pte *pe;
        unsigned i;

        i = read_int(1, 0, max, 0, "Partition number") - 1;
        pe = &ptes[i];

        if (warn) {
                if ((!LABEL_IS_SUN && !LABEL_IS_SGI && !pe->part_table->sys_ind)
                 || (LABEL_IS_SUN && (!sunlabel->partitions[i].num_sectors || !sunlabel->infos[i].id))
                 || (LABEL_IS_SGI && !sgi_get_num_sectors(i))
                ) {
                        printf("Warning: partition %u has empty type\n", i+1);
                }
        }
        return i;
}

static int
get_existing_partition(int warn, unsigned max)
{
        int pno = -1;
        unsigned i;

        for (i = 0; i < max; i++) {
                struct pte *pe = &ptes[i];
                struct partition *p = pe->part_table;

                if (p && !is_cleared_partition(p)) {
                        if (pno >= 0)
                                goto not_unique;
                        pno = i;
                }
        }
        if (pno >= 0) {
                printf("Selected partition %u\n", pno+1);
                return pno;
        }
        puts("No partition is defined yet!");
        return -1;

 not_unique:
        return get_partition(warn, max);
}

static int
get_nonexisting_partition(int warn, unsigned max)
{
        int pno = -1;
        unsigned i;

        for (i = 0; i < max; i++) {
                struct pte *pe = &ptes[i];
                struct partition *p = pe->part_table;

                if (p && is_cleared_partition(p)) {
                        if (pno >= 0)
                                goto not_unique;
                        pno = i;
                }
        }
        if (pno >= 0) {
                printf("Selected partition %u\n", pno+1);
                return pno;
        }
        puts("All primary partitions have been defined already!");
        return -1;

 not_unique:
        return get_partition(warn, max);
}


static void
change_units(void)
{
        display_in_cyl_units = !display_in_cyl_units;
        update_units();
        printf("Changing display/entry units to %s\n",
                str_units(PLURAL));
}

static void
toggle_active(int i)
{
        struct pte *pe = &ptes[i];
        struct partition *p = pe->part_table;

        if (IS_EXTENDED(p->sys_ind) && !p->boot_ind)
                printf("WARNING: Partition %u is an extended partition\n", i + 1);
        p->boot_ind = (p->boot_ind ? 0 : ACTIVE_FLAG);
        pe->changed = 1;
}

static void
toggle_dos_compatibility_flag(void)
{
        dos_compatible_flag = 1 - dos_compatible_flag;
        if (dos_compatible_flag) {
                sector_offset = g_sectors;
                printf("DOS Compatibility flag is %sset\n", "");
        } else {
                sector_offset = 1;
                printf("DOS Compatibility flag is %sset\n", "not ");
        }
}

static void
delete_partition(int i)
{
        struct pte *pe = &ptes[i];
        struct partition *p = pe->part_table;
        struct partition *q = pe->ext_pointer;

/* Note that for the fifth partition (i == 4) we don't actually
 * decrement partitions.
 */

        if (warn_geometry())
                return;         /* C/H/S not set */
        pe->changed = 1;

        if (LABEL_IS_SUN) {
                sun_delete_partition(i);
                return;
        }
        if (LABEL_IS_SGI) {
                sgi_delete_partition(i);
                return;
        }

        if (i < 4) {
                if (IS_EXTENDED(p->sys_ind) && i == ext_index) {
                        g_partitions = 4;
                        ptes[ext_index].ext_pointer = NULL;
                        extended_offset = 0;
                }
                clear_partition(p);
                return;
        }

        if (!q->sys_ind && i > 4) {
                /* the last one in the chain - just delete */
                --g_partitions;
                --i;
                clear_partition(ptes[i].ext_pointer);
                ptes[i].changed = 1;
        } else {
                /* not the last one - further ones will be moved down */
                if (i > 4) {
                        /* delete this link in the chain */
                        p = ptes[i-1].ext_pointer;
                        *p = *q;
                        set_start_sect(p, get_start_sect(q));
                        set_nr_sects(p, get_nr_sects(q));
                        ptes[i-1].changed = 1;
                } else if (g_partitions > 5) {    /* 5 will be moved to 4 */
                        /* the first logical in a longer chain */
                        pe = &ptes[5];

                        if (pe->part_table) /* prevent SEGFAULT */
                                set_start_sect(pe->part_table,
                                                get_partition_start_from_dev_start(pe) -
                                                extended_offset);
                        pe->offset_from_dev_start = extended_offset;
                        pe->changed = 1;
                }

                if (g_partitions > 5) {
                        g_partitions--;
                        while (i < g_partitions) {
                                ptes[i] = ptes[i+1];
                                i++;
                        }
                } else {
                        /* the only logical: clear only */
                        clear_partition(ptes[i].part_table);
                }
        }
}

static void
change_sysid(void)
{
        int i, sys, origsys;
        struct partition *p;

        /* If sgi_label then don't use get_existing_partition,
           let the user select a partition, since get_existing_partition()
           only works for Linux like partition tables. */
        if (!LABEL_IS_SGI) {
                i = get_existing_partition(0, g_partitions);
        } else {
                i = get_partition(0, g_partitions);
        }
        if (i == -1)
                return;
        p = ptes[i].part_table;
        origsys = sys = get_sysid(i);

        /* if changing types T to 0 is allowed, then
           the reverse change must be allowed, too */
        if (!sys && !LABEL_IS_SGI && !LABEL_IS_SUN && !get_nr_sects(p)) {
                printf("Partition %u does not exist yet!\n", i + 1);
                return;
        }
        while (1) {
                sys = read_hex(get_sys_types());

                if (!sys && !LABEL_IS_SGI && !LABEL_IS_SUN) {
                        puts("Type 0 means free space to many systems\n"
                                "(but not to Linux). Having partitions of\n"
                                "type 0 is probably unwise.");
                        /* break; */
                }

                if (!LABEL_IS_SUN && !LABEL_IS_SGI) {
                        if (IS_EXTENDED(sys) != IS_EXTENDED(p->sys_ind)) {
                                puts("You cannot change a partition into"
                                        " an extended one or vice versa");
                                break;
                        }
                }

                if (sys < 256) {
#if ENABLE_FEATURE_SUN_LABEL
                        if (LABEL_IS_SUN && i == 2 && sys != SUN_WHOLE_DISK)
                                puts("Consider leaving partition 3 "
                                        "as Whole disk (5),\n"
                                        "as SunOS/Solaris expects it and "
                                        "even Linux likes it\n");
#endif
#if ENABLE_FEATURE_SGI_LABEL
                        if (LABEL_IS_SGI &&
                                (
                                        (i == 10 && sys != SGI_ENTIRE_DISK) ||
                                        (i == 8 && sys != 0)
                                )
                        ) {
                                puts("Consider leaving partition 9 "
                                        "as volume header (0),\nand "
                                        "partition 11 as entire volume (6)"
                                        "as IRIX expects it\n");
                        }
#endif
                        if (sys == origsys)
                                break;
                        if (LABEL_IS_SUN) {
                                sun_change_sysid(i, sys);
                        } else if (LABEL_IS_SGI) {
                                sgi_change_sysid(i, sys);
                        } else
                                p->sys_ind = sys;

                        printf("Changed system type of partition %u "
                                "to %x (%s)\n", i + 1, sys,
                                partition_type(sys));
                        ptes[i].changed = 1;
                        //if (is_dos_partition(origsys) || is_dos_partition(sys))
                        //      dos_changed = 1;
                        break;
                }
        }
}
#endif /* FEATURE_FDISK_WRITABLE */


/* check_consistency() and linear2chs() added Sat Mar 6 12:28:16 1993,
 * faith@cs.unc.edu, based on code fragments from pfdisk by Gordon W. Ross,
 * Jan.  1990 (version 1.2.1 by Gordon W. Ross Aug. 1990; Modified by S.
 * Lubkin Oct.  1991). */

static void
linear2chs(unsigned ls, unsigned *c, unsigned *h, unsigned *s)
{
        int spc = g_heads * g_sectors;

        *c = ls / spc;
        ls = ls % spc;
        *h = ls / g_sectors;
        *s = ls % g_sectors + 1;  /* sectors count from 1 */
}

static void
check_consistency(const struct partition *p, int partition)
{
        unsigned pbc, pbh, pbs;          /* physical beginning c, h, s */
        unsigned pec, peh, pes;          /* physical ending c, h, s */
        unsigned lbc, lbh, lbs;          /* logical beginning c, h, s */
        unsigned lec, leh, les;          /* logical ending c, h, s */

        if (!g_heads || !g_sectors || (partition >= 4))
                return;         /* do not check extended partitions */

/* physical beginning c, h, s */
        pbc = cylinder(p->sector, p->cyl);
        pbh = p->head;
        pbs = sector(p->sector);

/* physical ending c, h, s */
        pec = cylinder(p->end_sector, p->end_cyl);
        peh = p->end_head;
        pes = sector(p->end_sector);

/* compute logical beginning (c, h, s) */
        linear2chs(get_start_sect(p), &lbc, &lbh, &lbs);

/* compute logical ending (c, h, s) */
        linear2chs(get_start_sect(p) + get_nr_sects(p) - 1, &lec, &leh, &les);

/* Same physical / logical beginning? */
        if (g_cylinders <= 1024 && (pbc != lbc || pbh != lbh || pbs != lbs)) {
                printf("Partition %u has different physical/logical "
                        "start (non-Linux?):\n", partition + 1);
                printf("     phys=(%u,%u,%u) ", pbc, pbh, pbs);
                printf("logical=(%u,%u,%u)\n", lbc, lbh, lbs);
        }

/* Same physical / logical ending? */

        if (g_cylinders <= 1024 && (pec != lec || peh != leh || pes != les)) {
                printf("Partition %u has different physical/logical "
                        "end:\n", partition + 1);
                printf("     phys=(%u,%u,%u) ", pec, peh, pes);
                printf("logical=(%u,%u,%u)\n", lec, leh, les);
        }
}

static void
list_disk_geometry(void)
{
        ullong bytes = ((ullong)total_number_of_sectors << 9);
        ullong xbytes = bytes / (1024*1024);
        char x = 'M';

        if (xbytes >= 10000) {
                xbytes += 512; /* fdisk util-linux 2.28 does this */
                xbytes /= 1024;
                x = 'G';
        }
        printf("Disk %s: %llu %cB, %llu bytes, %"SECT_FMT"u sectors\n"
                "%u cylinders, %u heads, %u sectors/track\n"
                "Units: %s of %u * %u = %u bytes\n\n",
                disk_device, xbytes, x,
                bytes, total_number_of_sectors,
                g_cylinders, g_heads, g_sectors,
                str_units(PLURAL),
                units_per_sector, sector_size, units_per_sector * sector_size
        );
}

/*
 * Check whether partition entries are ordered by their starting positions.
 * Return 0 if OK. Return i if partition i should have been earlier.
 * Two separate checks: primary and logical partitions.
 */
static int
wrong_p_order(int *prev)
{
        const struct pte *pe;
        const struct partition *p;
        sector_t last_p_start_pos = 0, p_start_pos;
        unsigned i, last_i = 0;

        for (i = 0; i < g_partitions; i++) {
                if (i == 4) {
                        last_i = 4;
                        last_p_start_pos = 0;
                }
                pe = &ptes[i];
                p = pe->part_table;
                if (p->sys_ind) {
                        p_start_pos = get_partition_start_from_dev_start(pe);

                        if (last_p_start_pos > p_start_pos) {
                                if (prev)
                                        *prev = last_i;
                                return i;
                        }

                        last_p_start_pos = p_start_pos;
                        last_i = i;
                }
        }
        return 0;
}

#if ENABLE_FEATURE_FDISK_ADVANCED
/*
 * Fix the chain of logicals.
 * extended_offset is unchanged, the set of sectors used is unchanged
 * The chain is sorted so that sectors increase, and so that
 * starting sectors increase.
 *
 * After this it may still be that cfdisk doesnt like the table.
 * (This is because cfdisk considers expanded parts, from link to
 * end of partition, and these may still overlap.)
 * Now
 *   sfdisk /dev/hda > ohda; sfdisk /dev/hda < ohda
 * may help.
 */
static void
fix_chain_of_logicals(void)
{
        int j, oj, ojj, sj, sjj;
        struct partition *pj,*pjj,tmp;

        /* Stage 1: sort sectors but leave sector of part 4 */
        /* (Its sector is the global extended_offset.) */
 stage1:
        for (j = 5; j < g_partitions - 1; j++) {
                oj = ptes[j].offset_from_dev_start;
                ojj = ptes[j+1].offset_from_dev_start;
                if (oj > ojj) {
                        ptes[j].offset_from_dev_start = ojj;
                        ptes[j+1].offset_from_dev_start = oj;
                        pj = ptes[j].part_table;
                        set_start_sect(pj, get_start_sect(pj)+oj-ojj);
                        pjj = ptes[j+1].part_table;
                        set_start_sect(pjj, get_start_sect(pjj)+ojj-oj);
                        set_start_sect(ptes[j-1].ext_pointer,
                                           ojj-extended_offset);
                        set_start_sect(ptes[j].ext_pointer,
                                           oj-extended_offset);
                        goto stage1;
                }
        }

        /* Stage 2: sort starting sectors */
 stage2:
        for (j = 4; j < g_partitions - 1; j++) {
                pj = ptes[j].part_table;
                pjj = ptes[j+1].part_table;
                sj = get_start_sect(pj);
                sjj = get_start_sect(pjj);
                oj = ptes[j].offset_from_dev_start;
                ojj = ptes[j+1].offset_from_dev_start;
                if (oj+sj > ojj+sjj) {
                        tmp = *pj;
                        *pj = *pjj;
                        *pjj = tmp;
                        set_start_sect(pj, ojj+sjj-oj);
                        set_start_sect(pjj, oj+sj-ojj);
                        goto stage2;
                }
        }

        /* Probably something was changed */
        for (j = 4; j < g_partitions; j++)
                ptes[j].changed = 1;
}


static void
fix_partition_table_order(void)
{
        struct pte *pei, *pek;
        int i,k;

        if (!wrong_p_order(NULL)) {
                puts("Ordering is already correct\n");
                return;
        }

        while ((i = wrong_p_order(&k)) != 0 && i < 4) {
                /* partition i should have come earlier, move it */
                /* We have to move data in the MBR */
                struct partition *pi, *pk, *pe, pbuf;
                pei = &ptes[i];
                pek = &ptes[k];

                pe = pei->ext_pointer;
                pei->ext_pointer = pek->ext_pointer;
                pek->ext_pointer = pe;

                pi = pei->part_table;
                pk = pek->part_table;

                memmove(&pbuf, pi, sizeof(struct partition));
                memmove(pi, pk, sizeof(struct partition));
                memmove(pk, &pbuf, sizeof(struct partition));

                pei->changed = pek->changed = 1;
        }

        if (i)
                fix_chain_of_logicals();

        puts("Done");
}
#endif

static const char *
chs_string11(unsigned cyl, unsigned head, unsigned sect)
{
        char *buf = auto_string(xzalloc(sizeof(int)*3 * 3));
        sprintf(buf, "%u,%u,%u", cylinder(sect,cyl), head, sector(sect));
        return buf;
}

static void
list_table(int xtra)
{
        int i, w;

        if (LABEL_IS_SUN) {
                sun_list_table(xtra);
                return;
        }
        if (LABEL_IS_SGI) {
                sgi_list_table(xtra);
                return;
        }
        if (LABEL_IS_GPT) {
                gpt_list_table(xtra);
                return;
        }

        list_disk_geometry();

        if (LABEL_IS_OSF) {
                xbsd_print_disklabel(xtra);
                return;
        }

        /* Heuristic: we list partition 3 of /dev/foo as /dev/foo3,
         * but if the device name ends in a digit, say /dev/foo1,
         * then the partition is called /dev/foo1p3.
         */
        w = strlen(disk_device);
        if (w && isdigit(disk_device[w-1]))
                w++;
        if (w < 7)
                w = 7;

        printf("%-*s Boot StartCHS    EndCHS        StartLBA     EndLBA    Sectors  Size Id Type\n",
                   w-1, "Device");

        for (i = 0; i < g_partitions; i++) {
                const struct partition *p;
                const struct pte *pe = &ptes[i];
                char boot4[4];
                char numstr6[6];
                sector_t start_sect;
                sector_t end_sect;
                sector_t nr_sects;

                p = pe->part_table;
                if (!p || is_cleared_partition(p))
                        continue;

                sprintf(boot4, "%02x", p->boot_ind);
                if ((p->boot_ind & 0x7f) == 0) {
                        /* 0x80 shown as '*', 0x00 is ' ' */
                        boot4[0] = p->boot_ind ? '*' : ' ';
                        boot4[1] = ' ';
                }

                start_sect = get_partition_start_from_dev_start(pe);
                end_sect = start_sect;
                nr_sects = get_nr_sects(p);
                if (nr_sects != 0)
                        end_sect += nr_sects - 1;

                smart_ulltoa5((ullong)nr_sects * sector_size,
                        numstr6, " KMGTPEZY")[0] = '\0';

#define SFMT SECT_FMT
                //      Boot StartCHS    EndCHS        StartLBA     EndLBA    Sectors  Size Id Type
                printf("%s%s %-11s"/**/" %-11s"/**/" %10"SFMT"u %10"SFMT"u %10"SFMT"u %s %2x %s\n",
                        partname(disk_device, i+1, w+2),
                        boot4,
                        chs_string11(p->cyl, p->head, p->sector),
                        chs_string11(p->end_cyl, p->end_head, p->end_sector),
                        start_sect,
                        end_sect,
                        nr_sects,
                        numstr6,
                        p->sys_ind,
                        partition_type(p->sys_ind)
                );
#undef SFMT
                check_consistency(p, i);
        }

        /* Is partition table in disk order? It need not be, but... */
        /* partition table entries are not checked for correct order
         * if this is a sgi, sun or aix labeled disk... */
        if (LABEL_IS_DOS && wrong_p_order(NULL)) {
                /* FIXME */
                puts("\nPartition table entries are not in disk order");
        }
}

#if ENABLE_FEATURE_FDISK_ADVANCED
static void
x_list_table(int extend)
{
        const struct pte *pe;
        const struct partition *p;
        int i;

        printf("\nDisk %s: %u heads, %u sectors, %u cylinders\n\n",
                disk_device, g_heads, g_sectors, g_cylinders);
        puts("Nr AF  Hd Sec  Cyl  Hd Sec  Cyl      Start       Size ID");
        for (i = 0; i < g_partitions; i++) {
                pe = &ptes[i];
                p = (extend ? pe->ext_pointer : pe->part_table);
                if (p != NULL) {
                        printf("%2u %02x%4u%4u%5u%4u%4u%5u%11"SECT_FMT"u%11"SECT_FMT"u %02x\n",
                                i + 1, p->boot_ind,
                                p->head,
                                sector(p->sector),
                                cylinder(p->sector, p->cyl),
                                p->end_head,
                                sector(p->end_sector),
                                cylinder(p->end_sector, p->end_cyl),
                                get_start_sect(p),
                                get_nr_sects(p),
                                p->sys_ind
                        );
                        if (p->sys_ind)
                                check_consistency(p, i);
                }
        }
}
#endif

#if ENABLE_FEATURE_FDISK_WRITABLE
static void
fill_bounds(sector_t *first, sector_t *last)
{
        unsigned i;
        const struct pte *pe = &ptes[0];
        const struct partition *p;

        for (i = 0; i < g_partitions; pe++,i++) {
                p = pe->part_table;
                if (!p->sys_ind || IS_EXTENDED(p->sys_ind)) {
                        first[i] = 0xffffffff;
                        last[i] = 0;
                } else {
                        first[i] = get_partition_start_from_dev_start(pe);
                        last[i] = first[i] + get_nr_sects(p) - 1;
                }
        }
}

static void
check(int n, unsigned h, unsigned s, unsigned c, sector_t start)
{
        sector_t total, real_s, real_c;

        real_s = sector(s) - 1;
        real_c = cylinder(s, c);
        total = (real_c * g_sectors + real_s) * g_heads + h;
        if (!total)
                printf("Partition %u contains sector 0\n", n);
        if (h >= g_heads)
                printf("Partition %u: head %u greater than maximum %u\n",
                        n, h + 1, g_heads);
        if (real_s >= g_sectors)
                printf("Partition %u: sector %u greater than "
                        "maximum %u\n", n, s, g_sectors);
        if (real_c >= g_cylinders)
                printf("Partition %u: cylinder %"SECT_FMT"u greater than "
                        "maximum %u\n", n, real_c + 1, g_cylinders);
        if (g_cylinders <= 1024 && start != total)
                printf("Partition %u: previous sectors %"SECT_FMT"u disagrees with "
                        "total %"SECT_FMT"u\n", n, start, total);
}

static void
verify(void)
{
        int i, j;
        sector_t total = 1;
        sector_t chs_size;
        sector_t first[g_partitions], last[g_partitions];
        struct partition *p;

        if (warn_geometry())
                return;

        if (LABEL_IS_SUN) {
                verify_sun();
                return;
        }
        if (LABEL_IS_SGI) {
                verify_sgi(1);
                return;
        }

        fill_bounds(first, last);
        for (i = 0; i < g_partitions; i++) {
                struct pte *pe = &ptes[i];

                p = pe->part_table;
                if (p->sys_ind && !IS_EXTENDED(p->sys_ind)) {
                        check_consistency(p, i);
                        if (get_partition_start_from_dev_start(pe) < first[i])
                                printf("Warning: bad start-of-data in "
                                        "partition %u\n", i + 1);
                        check(i + 1, p->end_head, p->end_sector, p->end_cyl,
                                last[i]);
                        total += last[i] + 1 - first[i];
                        for (j = 0; j < i; j++) {
                                if ((first[i] >= first[j] && first[i] <= last[j])
                                 || ((last[i] <= last[j] && last[i] >= first[j]))) {
                                        printf("Warning: partition %u overlaps "
                                                "partition %u\n", j + 1, i + 1);
                                        total += first[i] >= first[j] ?
                                                first[i] : first[j];
                                        total -= last[i] <= last[j] ?
                                                last[i] : last[j];
                                }
                        }
                }
        }

        if (extended_offset) {
                struct pte *pex = &ptes[ext_index];
                sector_t e_last = get_start_sect(pex->part_table) +
                        get_nr_sects(pex->part_table) - 1;

                for (i = 4; i < g_partitions; i++) {
                        total++;
                        p = ptes[i].part_table;
                        if (!p->sys_ind) {
                                if (i != 4 || i + 1 < g_partitions)
                                        printf("Warning: partition %u "
                                                "is empty\n", i + 1);
                        } else if (first[i] < extended_offset || last[i] > e_last) {
                                printf("Logical partition %u not entirely in "
                                        "partition %u\n", i + 1, ext_index + 1);
                        }
                }
        }

        chs_size = (sector_t)g_heads * g_sectors * g_cylinders;
        if (total > chs_size)
                printf("Total allocated sectors %u"
                        " greater than CHS size %"SECT_FMT"u\n",
                        total, chs_size
                );
        else {
                total = chs_size - total;
                if (total != 0)
                        printf("%"SECT_FMT"u unallocated sectors\n", total);
        }
}

static void
add_partition(int n, int sys)
{
        char mesg[256];         /* 48 does not suffice in Japanese */
        int i, num_read = 0;
        struct partition *p = ptes[n].part_table;
        struct partition *q = ptes[ext_index].part_table;
        sector_t limit, temp;
        sector_t start, stop = 0;
        sector_t first[g_partitions], last[g_partitions];

        if (p && p->sys_ind) {
                printf(msg_part_already_defined, n + 1);
                return;
        }
        fill_bounds(first, last);
        if (n < 4) {
                start = sector_offset;
                if (display_in_cyl_units || !total_number_of_sectors)
                        limit = (sector_t) g_heads * g_sectors * g_cylinders - 1;
                else
                        limit = total_number_of_sectors - 1;
                if (extended_offset) {
                        first[ext_index] = extended_offset;
                        last[ext_index] = get_start_sect(q) +
                                get_nr_sects(q) - 1;
                }
        } else {
                start = extended_offset + sector_offset;
                limit = get_start_sect(q) + get_nr_sects(q) - 1;
        }
        if (display_in_cyl_units)
                for (i = 0; i < g_partitions; i++)
                        first[i] = (cround(first[i]) - 1) * units_per_sector;

        snprintf(mesg, sizeof(mesg), "First %s", str_units(SINGULAR));
        do {
                temp = start;
                for (i = 0; i < g_partitions; i++) {
                        int lastplusoff;

                        if (start == ptes[i].offset_from_dev_start)
                                start += sector_offset;
                        lastplusoff = last[i] + ((n < 4) ? 0 : sector_offset);
                        if (start >= first[i] && start <= lastplusoff)
                                start = lastplusoff + 1;
                }
                if (start > limit)
                        break;
                if (start >= temp+units_per_sector && num_read) {
                        printf("Sector %"SECT_FMT"u is already allocated\n", temp);
                        temp = start;
                        num_read = 0;
                }
                if (!num_read && start == temp) {
                        sector_t saved_start;

                        saved_start = start;
                        start = read_int(cround(saved_start), cround(saved_start), cround(limit), 0, mesg);
                        if (display_in_cyl_units) {
                                start = (start - 1) * units_per_sector;
                                if (start < saved_start)
                                        start = saved_start;
                        }
                        num_read = 1;
                }
        } while (start != temp || !num_read);
        if (n > 4) {                    /* NOT for fifth partition */
                struct pte *pe = &ptes[n];

                pe->offset_from_dev_start = start - sector_offset;
                if (pe->offset_from_dev_start == extended_offset) { /* must be corrected */
                        pe->offset_from_dev_start++;
                        if (sector_offset == 1)
                                start++;
                }
        }

        for (i = 0; i < g_partitions; i++) {
                struct pte *pe = &ptes[i];

                if (start < pe->offset_from_dev_start && limit >= pe->offset_from_dev_start)
                        limit = pe->offset_from_dev_start - 1;
                if (start < first[i] && limit >= first[i])
                        limit = first[i] - 1;
        }
        if (start > limit) {
                puts("No free sectors available");
                if (n > 4)
                        g_partitions--;
                return;
        }
        if (cround(start) == cround(limit)) {
                stop = limit;
        } else {
                snprintf(mesg, sizeof(mesg),
                         "Last %s or +size{,K,M,G,T}",
                         str_units(SINGULAR)
                );
                stop = read_int(cround(start), cround(limit), cround(limit), cround(start), mesg);
                if (display_in_cyl_units) {
                        stop = stop * units_per_sector - 1;
                        if (stop >limit)
                                stop = limit;
                }
        }

        set_partition(n, 0, start, stop, sys);
        if (n > 4)
                set_partition(n - 1, 1, ptes[n].offset_from_dev_start, stop, EXTENDED);

        if (IS_EXTENDED(sys)) {
                struct pte *pe4 = &ptes[4];
                struct pte *pen = &ptes[n];

                ext_index = n;
                pen->ext_pointer = p;
                pe4->offset_from_dev_start = extended_offset = start;
                pe4->sectorbuffer = xzalloc(sector_size);
                pe4->part_table = pt_offset(pe4->sectorbuffer, 0);
                pe4->ext_pointer = pe4->part_table + 1;
                pe4->changed = 1;
                g_partitions = 5;
        }
}

static void
add_logical(void)
{
        if (g_partitions > 5 || ptes[4].part_table->sys_ind) {
                struct pte *pe = &ptes[g_partitions];

                pe->sectorbuffer = xzalloc(sector_size);
                pe->part_table = pt_offset(pe->sectorbuffer, 0);
                pe->ext_pointer = pe->part_table + 1;
                pe->offset_from_dev_start = 0;
                pe->changed = 1;
                g_partitions++;
        }
        add_partition(g_partitions - 1, LINUX_NATIVE);
}

static void
new_partition(void)
{
        int i, free_primary = 0;

        if (warn_geometry())
                return;

        if (LABEL_IS_SUN) {
                add_sun_partition(get_partition(0, g_partitions), LINUX_NATIVE);
                return;
        }
        if (LABEL_IS_SGI) {
                sgi_add_partition(get_partition(0, g_partitions), LINUX_NATIVE);
                return;
        }
        if (LABEL_IS_AIX) {
                puts("Sorry - this fdisk cannot handle AIX disk labels.\n"
"If you want to add DOS-type partitions, create a new empty DOS partition\n"
"table first (use 'o'). This will destroy the present disk contents.");
                return;
        }

        for (i = 0; i < 4; i++)
                free_primary += !ptes[i].part_table->sys_ind;

        if (!free_primary && g_partitions >= MAXIMUM_PARTS) {
                puts("The maximum number of partitions has been created");
                return;
        }

        if (!free_primary) {
                if (extended_offset)
                        add_logical();
                else
                        puts("You must delete some partition and add "
                                 "an extended partition first");
        } else {
                char c, line[80];
                snprintf(line, sizeof(line),
                        "Partition type\n"
                        "   p   primary partition (1-4)\n"
                        "   %s\n",
                        (extended_offset ?
                        "l   logical (5 or over)" : "e   extended"));
                while (1) {
                        c = read_nonempty(line);
                        if ((c | 0x20) == 'p') {
                                i = get_nonexisting_partition(0, 4);
                                if (i >= 0)
                                        add_partition(i, LINUX_NATIVE);
                                return;
                        }
                        if (c == 'l' && extended_offset) {
                                add_logical();
                                return;
                        }
                        if (c == 'e' && !extended_offset) {
                                i = get_nonexisting_partition(0, 4);
                                if (i >= 0)
                                        add_partition(i, EXTENDED);
                                return;
                        }
                        printf("Invalid partition number "
                                         "for type '%c'\n", c);
                }
        }
}

static void
reread_partition_table(int leave)
{
        int i;

        puts("Calling ioctl() to re-read partition table");
        sync();
        /* Users with slow external USB disks on a 320MHz ARM system (year 2011)
         * report that sleep is needed, otherwise BLKRRPART may fail with -EIO:
         */
        sleep(1);
        i = ioctl_or_perror(dev_fd, BLKRRPART, NULL,
                        "WARNING: rereading partition table "
                        "failed, kernel still uses old table");
#if 0
        if (dos_changed)
                puts(
                "\nWARNING: If you have created or modified any DOS 6.x\n"
                "partitions, please see the fdisk manual page for additional\n"
                "information");
#endif

        if (leave) {
                if (ENABLE_FEATURE_CLEAN_UP)
                        close_dev_fd();
                exit(i != 0);
        }
}

static void
write_table(void)
{
        int i;

        if (LABEL_IS_DOS) {
                for (i = 0; i < 3; i++)
                        if (ptes[i].changed)
                                ptes[3].changed = 1;
                for (i = 3; i < g_partitions; i++) {
                        struct pte *pe = &ptes[i];
                        if (pe->changed) {
                                write_part_table_flag(pe->sectorbuffer);
                                write_sector(pe->offset_from_dev_start, pe->sectorbuffer);
                        }
                }
        }
        else if (LABEL_IS_SGI) {
                /* no test on change? the "altered" msg below might be mistaken */
                sgi_write_table();
        }
        else if (LABEL_IS_SUN) {
                for (i = 0; i < 8; i++) {
                        if (ptes[i].changed) {
                                sun_write_table();
                                break;
                        }
                }
        }

        puts("The partition table has been altered.");
        reread_partition_table(1);
}
#endif /* FEATURE_FDISK_WRITABLE */

#if ENABLE_FEATURE_FDISK_ADVANCED
#define MAX_PER_LINE    16
static void
print_buffer(char *pbuffer)
{
        int i,l;

        for (i = 0, l = 0; i < sector_size; i++, l++) {
                if (l == 0)
                        printf("0x%03X:", i);
                printf(" %02X", (unsigned char) pbuffer[i]);
                if (l == MAX_PER_LINE - 1) {
                        bb_putchar('\n');
                        l = -1;
                }
        }
        if (l > 0)
                bb_putchar('\n');
        bb_putchar('\n');
}

static void
print_raw(void)
{
        int i;

        printf("Device: %s\n", disk_device);
        if (LABEL_IS_SGI || LABEL_IS_SUN)
                print_buffer(MBRbuffer);
        else {
                for (i = 3; i < g_partitions; i++)
                        print_buffer(ptes[i].sectorbuffer);
        }
}

static void
move_begin(unsigned i)
{
        struct pte *pe = &ptes[i];
        struct partition *p = pe->part_table;
        sector_t new, first, nr_sects;

        if (warn_geometry())
                return;
        nr_sects = get_nr_sects(p);
        if (!p->sys_ind || !nr_sects || IS_EXTENDED(p->sys_ind)) {
                printf("Partition %u has no data area\n", i + 1);
                return;
        }
        first = get_partition_start_from_dev_start(pe); /* == pe->offset_from_dev_start + get_start_sect(p) */
        new = read_int(0 /*was:first*/, first, first + nr_sects - 1, first, "New beginning of data");
        if (new != first) {
                sector_t new_relative = new - pe->offset_from_dev_start;
                nr_sects += (get_start_sect(p) - new_relative);
                set_start_sect(p, new_relative);
                set_nr_sects(p, nr_sects);
                read_nonempty("Recalculate C/H/S values? (Y/N): ");
                if ((line_ptr[0] | 0x20) == 'y')
                        set_hsc_start_end(p, new, new + nr_sects - 1);
                pe->changed = 1;
        }
}

static void
xselect(void)
{
        char c;

        while (1) {
                bb_putchar('\n');
                c = 0x20 | read_nonempty("Expert command (m for help): ");
                switch (c) {
                case 'a':
                        if (LABEL_IS_SUN)
                                sun_set_alt_cyl();
                        break;
                case 'b':
                        if (LABEL_IS_DOS)
                                move_begin(get_partition(0, g_partitions));
                        break;
                case 'c':
                        user_cylinders = g_cylinders =
                                read_int(1, g_cylinders, 1048576, 0,
                                        "Number of cylinders");
                        if (LABEL_IS_SUN)
                                sun_set_ncyl(g_cylinders);
                        if (LABEL_IS_DOS)
                                warn_cylinders();
                        break;
                case 'd':
                        print_raw();
                        break;
                case 'e':
                        if (LABEL_IS_SGI)
                                sgi_set_xcyl();
                        else if (LABEL_IS_SUN)
                                sun_set_xcyl();
                        else if (LABEL_IS_DOS)
                                x_list_table(1);
                        break;
                case 'f':
                        if (LABEL_IS_DOS)
                                fix_partition_table_order();
                        break;
                case 'g':
#if ENABLE_FEATURE_SGI_LABEL
                        create_sgilabel();
#endif
                        break;
                case 'h':
                        user_heads = g_heads = read_int(1, g_heads, 256, 0, "Number of heads");
                        update_units();
                        break;
                case 'i':
                        if (LABEL_IS_SUN)
                                sun_set_ilfact();
                        break;
                case 'o':
                        if (LABEL_IS_SUN)
                                sun_set_rspeed();
                        break;
                case 'p':
                        if (LABEL_IS_SUN)
                                list_table(1);
                        else
                                x_list_table(0);
                        break;
                case 'q':
                        if (ENABLE_FEATURE_CLEAN_UP)
                                close_dev_fd();
                        bb_putchar('\n');
                        exit(EXIT_SUCCESS);
                case 'r':
                        return;
                case 's':
                        user_sectors = g_sectors = read_int(1, g_sectors, 63, 0, "Number of sectors");
                        if (dos_compatible_flag) {
                                sector_offset = g_sectors;
                                puts("Warning: setting sector offset for DOS "
                                        "compatibility");
                        }
                        update_units();
                        break;
                case 'v':
                        verify();
                        break;
                case 'w':
                        write_table();  /* does not return */
                        break;
                case 'y':
                        if (LABEL_IS_SUN)
                                sun_set_pcylcount();
                        break;
                default:
                        xmenu();
                }
        }
}
#endif /* ADVANCED mode */

static int
is_ide_cdrom_or_tape(const char *device)
{
        FILE *procf;
        char buf[100];
        struct stat statbuf;
        int is_ide = 0;

        /* No device was given explicitly, and we are trying some
           likely things.  But opening /dev/hdc may produce errors like
           "hdc: tray open or drive not ready"
           if it happens to be a CD-ROM drive. It even happens that
           the process hangs on the attempt to read a music CD.
           So try to be careful. This only works since 2.1.73. */

        if (!is_prefixed_with(device, "/dev/hd"))
                return 0;

        snprintf(buf, sizeof(buf), "/proc/ide/%s/media", device+5);
        procf = fopen_for_read(buf);
        if (procf != NULL && fgets(buf, sizeof(buf), procf))
                is_ide = (is_prefixed_with(buf, "cdrom") ||
                          is_prefixed_with(buf, "tape"));
        else
                /* Now when this proc file does not exist, skip the
                   device when it is read-only. */
                if (stat(device, &statbuf) == 0)
                        is_ide = ((statbuf.st_mode & 0222) == 0);

        if (procf)
                fclose(procf);
        return is_ide;
}


static void
open_list_and_close(const char *device, int user_specified)
{
        int gb;

        disk_device = device;
        if (setjmp(listingbuf))
                return;
        if (!user_specified)
                if (is_ide_cdrom_or_tape(device))
                        return;

        /* Open disk_device, save file descriptor to dev_fd */
        errno = 0;
        gb = get_boot(TRY_ONLY);
        if (gb > 0) {   /* I/O error */
                /* Ignore other errors, since we try IDE
                   and SCSI hard disks which may not be
                   installed on the system. */
                if (user_specified || errno == EACCES)
                        bb_perror_msg("can't open '%s'", device);
                return;
        }

        if (gb < 0) { /* no DOS signature */
                list_disk_geometry();
                if (LABEL_IS_AIX)
                        goto ret;
#if ENABLE_FEATURE_OSF_LABEL
                if (bsd_trydev(device) < 0)
#endif
                        printf("Disk %s doesn't contain a valid "
                                "partition table\n", device);
        } else {
                list_table(0);
#if ENABLE_FEATURE_FDISK_WRITABLE
                if (!LABEL_IS_SUN && g_partitions > 4) {
                        delete_partition(ext_index);
                }
#endif
        }
 ret:
        close_dev_fd();
}

/* Is it a whole disk? The digit check is still useful
   for Xen devices for example. */
static int is_whole_disk(const char *disk)
{
        unsigned len;
        int fd = open(disk, O_RDONLY);

        if (fd != -1) {
                struct hd_geometry geometry;
                int err = ioctl(fd, HDIO_GETGEO, &geometry);
                close(fd);
                if (!err)
                        return (geometry.start == 0);
        }

        /* Treat "nameN" as a partition name, not whole disk */
        /* note: mmcblk0 should work from the geometry check above */
        len = strlen(disk);
        if (len != 0 && isdigit(disk[len - 1]))
                return 0;

        return 1;
}

/* for fdisk -l: try all things in /proc/partitions
   that look like a partition name (do not end in a digit) */
static void
list_devs_in_proc_partititons(void)
{
        FILE *procpt;
        char line[100], ptname[100], devname[120];
        int ma, mi, sz;

        procpt = fopen_or_warn("/proc/partitions", "r");

        while (fgets(line, sizeof(line), procpt)) {
                if (sscanf(line, " %u %u %u %[^\n ]",
                                &ma, &mi, &sz, ptname) != 4)
                        continue;

                sprintf(devname, "/dev/%s", ptname);
                if (is_whole_disk(devname))
                        open_list_and_close(devname, 0);
        }
#if ENABLE_FEATURE_CLEAN_UP
        fclose(procpt);
#endif
}

#if ENABLE_FEATURE_FDISK_WRITABLE
static void
unknown_command(int c)
{

        printf("%c: unknown command\n", c);
}
#endif

int fdisk_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fdisk_main(int argc UNUSED_PARAM, char **argv)
{
        unsigned opt;
        /*
         *  fdisk -v
         *  fdisk -l [-b sectorsize] [-u] device ...
         *  fdisk -s [partition] ...
         *  fdisk [-b sectorsize] [-u] device
         *
         * Options -C, -H, -S set the geometry.
         */
        INIT_G();

        close_dev_fd(); /* needed: fd 3 must not stay closed */

        opt = getopt32(argv, "b:+C:+H:+lS:+u" IF_FEATURE_FDISK_BLKSIZE("s"),
                                &sector_size, &user_cylinders, &user_heads, &user_sectors);
        argv += optind;
        if (opt & OPT_b) {
                /* Ugly: this sector size is really per device,
                 * so cannot be combined with multiple disks,
                 * and the same goes for the C/H/S options.
                 */
                if (sector_size < 512
                 || sector_size > 0x10000
                 || (sector_size & (sector_size-1)) /* not power of 2 */
                ) {
                        bb_show_usage();
                }
                sector_offset = 2;
                user_set_sector_size = 1;
        }
        if (user_heads <= 0 || user_heads >= 256)
                user_heads = 0;
        if (user_sectors <= 0 || user_sectors >= 64)
                user_sectors = 0;
        if (opt & OPT_u)
                display_in_cyl_units = 0; // -u

#if ENABLE_FEATURE_FDISK_WRITABLE
        if (opt & OPT_l) {
                nowarn = 1;
#endif
                if (*argv) {
                        listing = 1;
                        do {
                                open_list_and_close(*argv, 1);
                        } while (*++argv);
                } else {
                        /* we don't have device names, */
                        /* use /proc/partitions instead */
                        list_devs_in_proc_partititons();
                }
                return 0;
#if ENABLE_FEATURE_FDISK_WRITABLE
        }
#endif

#if ENABLE_FEATURE_FDISK_BLKSIZE
        if (opt & OPT_s) {
                int j;

                nowarn = 1;
                if (!argv[0])
                        bb_show_usage();
                for (j = 0; argv[j]; j++) {
                        unsigned long long size;
                        fd = xopen(argv[j], O_RDONLY);
                        size = bb_BLKGETSIZE_sectors(fd) / 2;
                        close(fd);
                        if (argv[1])
                                printf("%llu\n", size);
                        else
                                printf("%s: %llu\n", argv[j], size);
                }
                return 0;
        }
#endif

#if ENABLE_FEATURE_FDISK_WRITABLE
        if (!argv[0] || argv[1])
                bb_show_usage();

        disk_device = argv[0];
        get_boot(OPEN_MAIN);

        if (LABEL_IS_OSF) {
                /* OSF label, and no DOS label */
                printf("Detected an OSF/1 disklabel on %s, entering "
                        "disklabel mode\n", disk_device);
                bsd_select();
                /*Why do we do this?  It seems to be counter-intuitive*/
                current_label_type = LABEL_DOS;
                /* If we return we may want to make an empty DOS label? */
        }

        while (1) {
                int c;
                bb_putchar('\n');
                c = 0x20 | read_nonempty("Command (m for help): ");
                switch (c) {
                case 'a':
                        if (LABEL_IS_DOS)
                                toggle_active(get_partition(1, g_partitions));
                        else if (LABEL_IS_SUN)
                                toggle_sunflags(get_partition(1, g_partitions),
                                                0x01);
                        else if (LABEL_IS_SGI)
                                sgi_set_bootpartition(
                                        get_partition(1, g_partitions));
                        else
                                unknown_command(c);
                        break;
                case 'b':
                        if (LABEL_IS_SGI) {
                                printf("\nThe current boot file is: %s\n",
                                        sgi_get_bootfile());
                                if (read_maybe_empty("Please enter the name of the "
                                                "new boot file: ") == '\n')
                                        puts("Boot file unchanged");
                                else
                                        sgi_set_bootfile(line_ptr);
                        }
#if ENABLE_FEATURE_OSF_LABEL
                        else
                                bsd_select();
#endif
                        break;
                case 'c':
                        if (LABEL_IS_DOS)
                                toggle_dos_compatibility_flag();
                        else if (LABEL_IS_SUN)
                                toggle_sunflags(get_partition(1, g_partitions),
                                                0x10);
                        else if (LABEL_IS_SGI)
                                sgi_set_swappartition(
                                                get_partition(1, g_partitions));
                        else
                                unknown_command(c);
                        break;
                case 'd':
                        {
                                int j;
                        /* If sgi_label then don't use get_existing_partition,
                           let the user select a partition, since
                           get_existing_partition() only works for Linux-like
                           partition tables */
                                if (!LABEL_IS_SGI) {
                                        j = get_existing_partition(1, g_partitions);
                                } else {
                                        j = get_partition(1, g_partitions);
                                }
                                if (j >= 0)
                                        delete_partition(j);
                        }
                        break;
                case 'i':
                        if (LABEL_IS_SGI)
                                create_sgiinfo();
                        else
                                unknown_command(c);
                case 'l':
                        list_types(get_sys_types());
                        break;
                case 'm':
                        menu();
                        break;
                case 'n':
                        new_partition();
                        break;
                case 'o':
                        create_doslabel();
                        break;
                case 'p':
                        list_table(0);
                        break;
                case 'q':
                        if (ENABLE_FEATURE_CLEAN_UP)
                                close_dev_fd();
                        bb_putchar('\n');
                        return 0;
                case 's':
#if ENABLE_FEATURE_SUN_LABEL
                        create_sunlabel();
#endif
                        break;
                case 't':
                        change_sysid();
                        break;
                case 'u':
                        change_units();
                        break;
                case 'v':
                        verify();
                        break;
                case 'w':
                        write_table();  /* does not return */
                        break;
#if ENABLE_FEATURE_FDISK_ADVANCED
                case 'x':
                        if (LABEL_IS_SGI) {
                                puts("\n\tSorry, no experts menu for SGI "
                                        "partition tables available\n");
                        } else
                                xselect();
                        break;
#endif
                default:
                        unknown_command(c);
                        menu();
                }
        }
        return 0;
#endif /* FEATURE_FDISK_WRITABLE */
}