sfdisk.c

Util-linux 软件包包含许多工具。其中比较重要的是加载、卸载、格式化、分区和管理硬盘驱动器

/*
 * sfdisk version 3.0 - aeb - 950813
 *
 * Copyright (C) 1995  Andries E. Brouwer ([e-mail])
 *
 * This program is free software. You can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation: either Version 1
 * or (at your option) any later version.
 *
 * A.V. Le Blanc ([e-mail]) wrote Linux fdisk 1992-1994,
 * patched by various people ([e-mail], [e-mail],
 * [e-mail], [e-mail], [e-mail])
 * 1993-1995, with version numbers (as far as I have seen) 0.93 - 2.0e.
 * This program had (head,sector,cylinder) as basic unit, and was
 * (therefore) broken in several ways for the use on larger disks -
 * for example, my last patch (from 2.0d to 2.0e) was required
 * to allow a partition to cross cylinder 8064, and to write an
 * extended partition past the 4GB mark.
 *
 * The current program is a rewrite from scratch, and I started a
 * version numbering at 3.0.
 * 	Andries Brouwer, [e-mail], 950813
 *
 * Well, a good user interface is still lacking. On the other hand,
 * many configurations cannot be handled by any other fdisk.
 * I changed the name to sfdisk to prevent confusion. - aeb, 970501
 *
 * Changes:
 * 19990319 - Arnaldo Carvalho de Melo <[e-mail]> - i18n
 * 20040428 - Jeroen Dobbelaere <[e-mail]> - added PACKED
 * 20040824 - David A. Wheeler <[e-mail]> - warnings to stderr
 */

#define PROGNAME "sfdisk"
#define VERSION "3.08"
#define DATE "040824"

#include <stdio.h>
#include <stdlib.h>		/* atoi, free */
#include <stdarg.h>		/* varargs */
#include <unistd.h>		/* read, write */
#include <fcntl.h>		/* O_RDWR */
#include <errno.h>		/* ERANGE */
#include <string.h>		/* index() */
#include <ctype.h>
#include <getopt.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <linux/unistd.h>	/* _syscall */
#include "nls.h"
#include "common.h"

#define SIZE(a)	(sizeof(a)/sizeof(a[0]))

/*
 * Table of contents:
 *  A. About seeking
 *  B. About sectors
 *  C. About heads, sectors and cylinders
 *  D. About system Ids
 *  E. About partitions
 *  F. The standard input
 *  G. The command line
 *  H. Listing the current situation
 *  I. Writing the new situation
 */
int exit_status = 0;

int force = 0;		/* 1: do what I say, even if it is stupid ... */
int quiet = 0;		/* 1: suppress all warnings */
/* IA-64 gcc spec file currently does -DLinux... */
#undef Linux
int Linux = 0;		/* 1: suppress warnings irrelevant for Linux */
int DOS = 0;		/* 1: shift extended partitions by #sectors, not 1 */
int DOS_extended = 0;	/* 1: use starting cylinder boundary of extd partn */
int dump = 0;           /* 1: list in a format suitable for later input */
int verify = 0;         /* 1: check that listed partition is reasonable */
int no_write = 0;	/* 1: do not actually write to disk */
int no_reread = 0;	/* 1: skip the BLKRRPART ioctl test at startup */
int leave_last = 0;	/* 1: don't allocate the last cylinder */
int opt_list = 0;
char *save_sector_file = NULL;
char *restore_sector_file = NULL;

static void
do_warn(char *s, ...) {
    va_list p;

    va_start(p, s);
    fflush(stdout);
    vfprintf(stderr, s, p);
    fflush(stderr);
    va_end(p);
}

static void
warn(char *s, ...) {
    va_list p;

    va_start(p, s);
    if (!quiet) {
	fflush(stdout);
	vfprintf(stderr, s, p);
	fflush(stderr);
    }
    va_end(p);
}

static void
error(char *s, ...) {
    va_list p;

    va_start(p, s);
    fflush(stdout);
    fprintf(stderr, "\n" PROGNAME ": ");
    vfprintf(stderr, s, p);
    fflush(stderr);
    va_end(p);
}

static void
fatal(char *s, ...) {
    va_list p;

    va_start(p, s);
    fflush(stdout);
    fprintf(stderr, "\n" PROGNAME ": ");
    vfprintf(stderr, s, p);
    fflush(stderr);
    va_end(p);
    exit(1);
}

/*
 * GCC nonsense - needed for GCC 3.4.x with -O2
 *
 * Maybe just test with #if (__GNUC__ >= 3) && (__GNUC_MINOR__ >= 4) ?
 */
#ifndef __GNUC_PREREQ
#define __GNUC_PREREQ(x,y)	0
#endif
#if __GNUC_PREREQ(3,4)
#define __attribute__used __attribute__ ((used))
#else
#define __attribute__used
#endif

/*
 * arm needs PACKED - use it everywhere?
 */
#if defined(__GNUC__) && defined(__arm__)
# define PACKED __attribute__ ((packed))
#else
# define PACKED
#endif


/*
 *  A. About seeking
 */

/*
 * sseek: seek to specified sector - return 0 on failure
 *
 * For >4GB disks lseek needs a > 32bit arg, and we have to use llseek.
 * On the other hand, a 32 bit sector number is OK until 2TB.
 * The routines _llseek and sseek below are the only ones that
 * know about the loff_t type.
 *
 * Note: we use 512-byte sectors here, irrespective of the hardware ss.
 */
#undef use_lseek
#if defined (__alpha__) || defined (__ia64__) || defined (__x86_64__) || defined (__s390x__)
#define use_lseek
#endif

#ifndef use_lseek
static __attribute__used
_syscall5(int,  _llseek,  unsigned int,  fd, ulong, hi, ulong, lo,
       loff_t *, res, unsigned int, wh);
#endif

static int
sseek(char *dev, unsigned int fd, unsigned long s) {
    loff_t in, out;
    in = ((loff_t) s << 9);
    out = 1;

#ifndef use_lseek
    if (_llseek (fd, in>>32, in & 0xffffffff, &out, SEEK_SET) != 0) {
#else
    if ((out = lseek(fd, in, SEEK_SET)) != in) {
#endif
	perror("llseek");
	error(_("seek error on %s - cannot seek to %lu\n"), dev, s);
	return 0;
    }

    if (in != out) {
	error(_("seek error: wanted 0x%08x%08x, got 0x%08x%08x\n"),
	       (unsigned int)(in>>32), (unsigned int)(in & 0xffffffff),
	       (unsigned int)(out>>32), (unsigned int)(out & 0xffffffff));
	return 0;
    }
    return 1;
}

/*
 *  B. About sectors
 */

/*
 * We preserve all sectors read in a chain - some of these will
 * have to be modified and written back.
 */
struct sector {
    struct sector *next;
    unsigned long sectornumber;
    int to_be_written;
    char data[512];
} *sectorhead;

static void
free_sectors(void) {
    struct sector *s;

    while (sectorhead) {
	s = sectorhead;
	sectorhead = s->next;
	free(s);
    }
}

static struct sector *
get_sector(char *dev, int fd, unsigned long sno) {
    struct sector *s;

    for(s = sectorhead; s; s = s->next)
	if (s->sectornumber == sno)
	    return s;

    if (!sseek(dev, fd, sno))
	return 0;

    if (!(s = (struct sector *) malloc(sizeof(struct sector))))
	fatal(_("out of memory - giving up\n"));

    if (read(fd, s->data, sizeof(s->data)) != sizeof(s->data)) {
	if (errno)		/* 0 in case we read past end-of-disk */
	    perror("read");
	error(_("read error on %s - cannot read sector %lu\n"), dev, sno);
	free(s);
	return 0;
    }

    s->next = sectorhead;
    sectorhead = s;
    s->sectornumber = sno;
    s->to_be_written = 0;

    return s;
}

static int
msdos_signature (struct sector *s) {
    unsigned char *data = s->data;
    if (data[510] == 0x55 && data[511] == 0xaa)
	    return 1;
    error(_("ERROR: sector %lu does not have an msdos signature\n"),
	  s->sectornumber);
    return 0;
}

static int
write_sectors(char *dev, int fd) {
    struct sector *s;

    for (s = sectorhead; s; s = s->next)
	if (s->to_be_written) {
	    if (!sseek(dev, fd, s->sectornumber))
		return 0;
	    if (write(fd, s->data, sizeof(s->data)) != sizeof(s->data)) {
		perror("write");
		error(_("write error on %s - cannot write sector %lu\n"),
		       dev, s->sectornumber);
		return 0;
	    }
	    s->to_be_written = 0;
	}
    return 1;
}

static void
ulong_to_chars(unsigned long u, char *uu) {
    int i;

    for(i=0; i<4; i++) {
	uu[i] = (u & 0xff);
	u >>= 8;
    }
}

static unsigned long
chars_to_ulong(unsigned char *uu) {
    int i;
    unsigned long u = 0;

    for(i=3; i>=0; i--)
	u = (u << 8) | uu[i];
    return u;
}

static int
save_sectors(char *dev, int fdin) {
    struct sector *s;
    char ss[516];
    int fdout;

    fdout = open(save_sector_file, O_WRONLY | O_CREAT, 0444);
    if (fdout < 0) {
	perror(save_sector_file);
	error(_("cannot open partition sector save file (%s)\n"),
	       save_sector_file);
	return 0;
    }

    for (s = sectorhead; s; s = s->next)
	if (s->to_be_written) {
	    ulong_to_chars(s->sectornumber, ss);
	    if (!sseek(dev, fdin, s->sectornumber))
		return 0;
	    if (read(fdin, ss+4, 512) != 512) {
		perror("read");
		error(_("read error on %s - cannot read sector %lu\n"),
		       dev, s->sectornumber);
		return 0;
	    }
	    if (write(fdout, ss, sizeof(ss)) != sizeof(ss)) {
		perror("write");
		error(_("write error on %s\n"), save_sector_file);
		return 0;
	    }
	}
    return 1;
}

static void reread_disk_partition(char *dev, int fd);

static int
restore_sectors(char *dev) {
    int fdin, fdout, ct;
    struct stat statbuf;
    char *ss0, *ss;
    unsigned long sno;

    if (stat(restore_sector_file, &statbuf) < 0) {
	perror(restore_sector_file);
	error(_("cannot stat partition restore file (%s)\n"),
	       restore_sector_file);
	return 0;
    }
    if (statbuf.st_size % 516) {
	error(_("partition restore file has wrong size - not restoring\n"));
	return 0;
    }
    if (!(ss = (char *) malloc(statbuf.st_size))) {
	error(_("out of memory?\n"));
	return 0;
    }
    fdin = open(restore_sector_file, O_RDONLY);
    if (fdin < 0) {
	perror(restore_sector_file);
	error(_("cannot open partition restore file (%s)\n"),
	       restore_sector_file);
	return 0;
    }
    if (read(fdin, ss, statbuf.st_size) != statbuf.st_size) {
	perror("read");
	error(_("error reading %s\n"), restore_sector_file);
	return 0;
    }

    fdout = open(dev, O_WRONLY);
    if (fdout < 0) {
	perror(dev);
	error(_("cannot open device %s for writing\n"), dev);
	return 0;
    }

    ss0 = ss;
    ct = statbuf.st_size/516;
    while(ct--) {
	sno = chars_to_ulong(ss);
	if (!sseek(dev, fdout, sno))
	  return 0;
	if (write(fdout, ss+4, 512) != 512) {
	    perror(dev);
	    error(_("error writing sector %lu on %s\n"), sno, dev);
	    return 0;
	}
	ss += 516;
    }
    free(ss0);

    reread_disk_partition(dev, fdout);

    return 1;
}

/*
 *  C. About heads, sectors and cylinders
 */

/*
 * <linux/hdreg.h> defines HDIO_GETGEO and
 * struct hd_geometry {
 *      unsigned char heads;
 *      unsigned char sectors;
 *      unsigned short cylinders;
 *      unsigned long start;
 * };
 *
 * For large disks g.cylinders is truncated, so we use BLKGETSIZE.
 */

/*
 * We consider several geometries for a disk:
 * B - the BIOS geometry, gotten from the kernel via HDIO_GETGEO
 * F - the fdisk geometry
 * U - the user-specified geometry
 *
 * 0 means unspecified / unknown
 */
struct geometry {
	unsigned long long total_size;		/* in sectors */
	unsigned long cylindersize;		/* in sectors */
	unsigned long heads, sectors, cylinders;
	unsigned long start;
} B, F, U;

static struct geometry
get_geometry(char *dev, int fd, int silent) {
    struct hd_geometry g;
    unsigned long cyls;
    unsigned long long sectors;
    struct geometry R;

    if (ioctl(fd, HDIO_GETGEO, &g)) {
	g.heads = g.sectors = g.cylinders = g.start = 0;
	if (!silent)
	    do_warn(_("Disk %s: cannot get geometry\n"), dev);
    }

    R.start = g.start;
    R.heads = g.heads;
    R.sectors = g.sectors;
    R.cylindersize = R.heads * R.sectors;
    R.cylinders = 0;
    R.total_size = 0;

    if (disksize(fd, &sectors)) {
	/* maybe an ordinary file */
	struct stat s;

	if (fstat(fd, &s) == 0 && S_ISREG(s.st_mode))
	    R.total_size = (s.st_size >> 9);
	else if (!silent)
	    do_warn(_("Disk %s: cannot get size\n"), dev);
    } else
	    R.total_size = sectors;

    if (R.cylindersize && R.total_size) {
	    sectors /= R.cylindersize;
	    cyls = sectors;
	    if (cyls != sectors)
		    cyls = ~0;
	    R.cylinders = cyls;