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

    z->partno = pno;
}

#define BSD_DISKMAGIC   (0x82564557UL)
#define BSD_MAXPARTITIONS       16
#define BSD_FS_UNUSED	   0
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
struct bsd_disklabel {
	u32	d_magic;
	char	d_junk1[4];
	char    d_typename[16];
	char    d_packname[16];
	char	d_junk2[92];
	u32	d_magic2;
	char	d_junk3[2];
	u16	d_npartitions;          /* number of partitions in following */
	char	d_junk4[8];
     struct  bsd_partition {         /* the partition table */
                u32   p_size;         /* number of sectors in partition */
                u32   p_offset;       /* starting sector */
                u32   p_fsize;        /* filesystem basic fragment size */
                u8    p_fstype;       /* filesystem type, see below */
                u8    p_frag;         /* filesystem fragments per block */
                u16   p_cpg;          /* filesystem cylinders per group */
     } d_partitions[BSD_MAXPARTITIONS];      /* actually may be more */
};

static void
bsd_partition(char *dev, int fd, struct part_desc *ep, struct disk_desc *z) {
	struct bsd_disklabel *l;
	struct bsd_partition *bp, *bp0;
	unsigned long start = ep->start;
	struct sector *s;
	struct part_desc *partitions = &(z->partitions[0]);
	int pno = z->partno;

	if (!(s = get_sector(dev,fd,start+1)))
		return;
	l = (struct bsd_disklabel *) (s->data);
	if (l->d_magic != BSD_DISKMAGIC || l->d_magic2 != BSD_DISKMAGIC)
		return;

	bp = bp0 = &l->d_partitions[0];
	while (bp - bp0 < BSD_MAXPARTITIONS && bp - bp0 < l->d_npartitions) {
		if (pno+1 >= SIZE(z->partitions)) {
			do_warn(_("too many partitions - ignoring those "
			       "past nr (%d)\n"), pno-1);
			break;
		}
		if (bp->p_fstype != BSD_FS_UNUSED) {
			partitions[pno].start = bp->p_offset;
			partitions[pno].size = bp->p_size;
			partitions[pno].sector = start+1;
			partitions[pno].offset = (char *)bp - (char *)bp0;
			partitions[pno].ep = 0;
			partitions[pno].ptype = BSD_TYPE;
			pno++;
		}
		bp++;
	}
	z->partno = pno;
}

#define MAKE_VERSION(p,q,r)     (65536*(p) + 256*(q) + (r))

static int
linux_version_code(void) {
        struct utsname my_utsname;
        int p, q, r;

        if (uname(&my_utsname) == 0) {
                p = atoi(strtok(my_utsname.release, "."));
                q = atoi(strtok(NULL, "."));
                r = atoi(strtok(NULL, "."));
                return MAKE_VERSION(p,q,r);
        }
        return 0;
}

static int
msdos_partition(char *dev, int fd, unsigned long start, struct disk_desc *z) {
    int i;
    char *cp;
    struct partition pt;
    struct sector *s;
    struct part_desc *partitions = &(z->partitions[0]);
    int pno = z->partno;
    int bsd_later = (linux_version_code() >= MAKE_VERSION(2,3,40));

    if (!(s = get_sector(dev, fd, start)))
	return 0;

    if (!msdos_signature(s))
	return 0;

    cp = s->data + 0x1be;
    copy_to_part(cp,&pt);

    /* If I am not mistaken, recent kernels will hide this from us,
	   so we will never actually see traces of a Disk Manager */
    if (pt.sys_type == DM6_PARTITION
	|| pt.sys_type == EZD_PARTITION
	|| pt.sys_type == DM6_AUX1PARTITION
	|| pt.sys_type == DM6_AUX3PARTITION) {
	do_warn(_("detected Disk Manager - unable to handle that\n"));
	return 0;
    }
    { unsigned int sig = *(unsigned short *)(s->data + 2);
      if (sig <= 0x1ae
	  && *(unsigned short *)(s->data + sig) == 0x55aa
	  && (1 & *(unsigned char *)(s->data + sig + 2))) {
	  do_warn(_("DM6 signature found - giving up\n"));
	  return 0;
      }
    }

    for (pno=0; pno<4; pno++,cp += sizeof(struct partition)) {
	partitions[pno].sector = start;
	partitions[pno].offset = cp - s->data;
	copy_to_part(cp,&pt);
	partitions[pno].start = start + pt.start_sect;
	partitions[pno].size = pt.nr_sects;
	partitions[pno].ep = 0;
	partitions[pno].p = pt;
    }

    z->partno = pno;

    for (i=0; i<4; i++) {
	if (is_extended(partitions[i].p.sys_type)) {
	    if (!partitions[i].size) {
		do_warn(_("strange..., an extended partition of size 0?\n"));
		continue;
	    }
	    extended_partition(dev, fd, &partitions[i], z);
	}
	if (!bsd_later && is_bsd(partitions[i].p.sys_type)) {
	    if (!partitions[i].size) {
		do_warn(_("strange..., a BSD partition of size 0?\n"));
		continue;
	    }
	    bsd_partition(dev, fd, &partitions[i], z);
	}
    }

    if (bsd_later) {
	for (i=0; i<4; i++) {
	    if (is_bsd(partitions[i].p.sys_type)) {
		if (!partitions[i].size) {
		    do_warn(_("strange..., a BSD partition of size 0?\n"));
		    continue;
		}
		bsd_partition(dev, fd, &partitions[i], z);
	    }
	}
    }
	    
    return 1;
}

static int
osf_partition(char *dev, int fd, unsigned long start, struct disk_desc *z) {
	return 0;
}

static int
sun_partition(char *dev, int fd, unsigned long start, struct disk_desc *z) {
	return 0;
}

static int
amiga_partition(char *dev, int fd, unsigned long start, struct disk_desc *z) {
	return 0;
}

static void
get_partitions(char *dev, int fd, struct disk_desc *z) {
    z->partno = 0;

    if (!msdos_partition(dev, fd, 0, z)
	&& !osf_partition(dev, fd, 0, z)
	&& !sun_partition(dev, fd, 0, z)
	&& !amiga_partition(dev, fd, 0, z)) {
	do_warn(_(" %s: unrecognized partition table type\n"), dev);
	return;
    }
}

static int
write_partitions(char *dev, int fd, struct disk_desc *z) {
    struct sector *s;
    struct part_desc *partitions = &(z->partitions[0]), *p;
    int pno = z->partno;

    if (no_write) {
	do_warn(_("-n flag was given: Nothing changed\n"));
	exit(0);
    }

    for (p = partitions; p < partitions+pno; p++) {
	s = get_sector(dev, fd, p->sector);
	if (!s) return 0;
	s->to_be_written = 1;
	if (p->ptype == DOS_TYPE) {
	    copy_from_part(&(p->p), s->data + p->offset);
	    s->data[510] = 0x55;
	    s->data[511] = 0xaa;
	}
    }
    if (save_sector_file) {
	if (!save_sectors(dev, fd)) {
	    fatal(_("Failed saving the old sectors - aborting\n"));
	    return 0;
	}
    }
    if (!write_sectors(dev, fd)) {
	error(_("Failed writing the partition on %s\n"), dev);
	return 0;
    }
    return 1;
}

/*
 *  F. The standard input
 */

/*
 * Input format:
 * <start> <size> <type> <bootable> <c,h,s> <c,h,s>
 * Fields are separated by whitespace or comma or semicolon possibly
 * followed by whitespace; initial and trailing whitespace is ignored.
 * Numbers can be octal, decimal or hexadecimal, decimal is default
 * The <c,h,s> parts can (and probably should) be omitted.
 * Bootable is specified as [*|-], with as default not-bootable.
 * Type is given in hex, without the 0x prefix, or is [E|S|L|X], where
 * L (LINUX_NATIVE (83)) is the default, S is LINUX_SWAP (82), and E
 * is EXTENDED_PARTITION (5), X is LINUX_EXTENDED (85).
 * The default value of start is the first nonassigned sector/cylinder/...
 * The default value of size is as much as possible (until next
 * partition or end-of-disk).
 * .: end of chain of extended partitions.
 *
 * On interactive input an empty line means: all defaults.
 * Otherwise empty lines are ignored.
 */

int eof, eob;

struct dumpfld {
    int fldno;
    char *fldname;
    int is_bool;
} dumpflds[] = {
    { 0, "start", 0 },
    { 1, "size", 0 },
    { 2, "Id", 0 },
    { 3, "bootable", 1 },
    { 4, "bh", 0 },
    { 5, "bs", 0 },
    { 6, "bc", 0 },
    { 7, "eh", 0 },
    { 8, "es", 0 },
    { 9, "ec", 0 }
};

/*
 * Read a line, split it into fields
 *
 * (some primitive handwork, but a more elaborate parser seems
 *  unnecessary)
 */
#define RD_EOF (-1)
#define RD_CMD (-2)

static int
read_stdin(unsigned char **fields, unsigned char *line, int fieldssize, int linesize) {
    unsigned char *lp, *ip;
    int c, fno;

    /* boolean true and empty string at start */
    line[0] = '*';
    line[1] = 0;
    for (fno=0; fno < fieldssize; fno++)
      fields[fno] = line + 1;
    fno = 0;

    /* read a line from stdin */
    lp = fgets(line+2, linesize, stdin);
    if (lp == NULL) {
	eof = 1;
	return RD_EOF;
    }
    if (!(lp = index(lp, '\n')))
      fatal(_("long or incomplete input line - quitting\n"));
    *lp = 0;

    /* remove comments, if any */
    if ((lp = index(line+2, '#')) != 0)
      *lp = 0;

    /* recognize a few commands - to be expanded */
    if (!strcmp(line+2, "unit: sectors")) {
	specified_format = F_SECTOR;
	return RD_CMD;
    }

    /* dump style? - then bad input is fatal */
    if ((ip = index(line+2, ':')) != 0) {
	struct dumpfld *d;

      nxtfld:
	    ip++;
	    while(isspace(*ip))
	      ip++;
	    if (*ip == 0)
	      return fno;
	    for(d = dumpflds; d-dumpflds < SIZE(dumpflds); d++) {
		if (!strncmp(ip, d->fldname, strlen(d->fldname))) {
		    ip += strlen(d->fldname);
		    while(isspace(*ip))
		      ip++;
		    if (d->is_bool)
			fields[d->fldno] = line;
		    else if (*ip == '=') {
			while(isspace(*++ip)) ;
			fields[d->fldno] = ip;
			while(isalnum(*ip)) 	/* 0x07FF */
			  ip++;
		    } else
		      fatal(_("input error: `=' expected after %s field\n"),
			    d->fldname);
		    if (fno <= d->fldno)
		      fno = d->fldno + 1;
		    if (*ip == 0)
		      return fno;
		    if (*ip != ',' && *ip != ';')
		      fatal(_("input error: unexpected character %c after %s field\n"),
			    *ip, d->fldname);
		    *ip = 0;
		    goto nxtfld;
		}
	    }
	    fatal(_("unrecognized input: %s\n"), ip);
    }

    /* split line into fields */
    lp = ip = line+2;
    fields[fno++] = lp;
    while((c = *ip++) != 0) {
	if (!lp[-1] && (c == '\t' || c == ' '))
	  ;
	else if (c == '\t' || c == ' ' || c == ',' || c == ';') {
	    *lp++ = 0;
	    if (fno < fieldssize)
		fields[fno++] = lp;
	    continue;
	} else
	  *lp++ = c;
    }

    if (lp == fields[fno-1])
      fno--;
    return fno;
}

/* read a number, use default if absent */
/* a sign gives an offset from the default */
static int
get_ul(char *u, unsigned long *up, unsigned long def, int base) {
    char *nu;
    int sign = 0;
    unsigned long val;

    if (*u == '+') {
	sign = 1;
	u++;
    } else if (*u == '-') {
	sign = -1;
	u++;
    }
    if (*u) {
	errno = 0;
	val = strtoul(u, &nu, base);
	if (errno == ERANGE) {
	    do_warn(_("number too big\n"));
	    return -1;
	}
	if (*nu) {
	    do_warn(_("trailing junk after number\n"));
	    return -1;
	}
	if (sign == 1)
		val = def + val;
	else if (sign == -1)
		val = def - val;
	*up = val;
    } else
      *up = def;
    return 0;
}

/* There are two common ways to structure extended partitions:
   as nested boxes, and as a chain. Sometimes the partitions
   must be given in order. Sometimes all logical partitions
   must lie inside the outermost extended partition.
NESTED: every partition is contained in the surrounding partitions
   and is disjoint from all others.
CHAINED: every data partition is contained in the surrounding partitions
   and disjoint from all others, but extended partitions may lie outside
   (insofar as allowed by all_logicals_inside_outermost_extended).
ONESECTOR: all data partitions are mutually disjoint; extended partitions
   each use one sector only (except perhaps for the outermost one).
*/
int partitions_in_order = 0;
int all_logicals_inside_outermost_extended = 1;
enum { NESTED, CHAINED, ONESECTOR } boxes = NESTED;

/* find the default value for <start> - assuming entire units */
static unsigned long
first_free(int pno, int is_extended, struct part_desc *ep, int format,
	   unsigned long mid, struct disk_desc *z) {
    unsigned long ff, fff;
    unsigned long unit = unitsize(format);
    struct part_desc *partitions = &(z->partitions[0]), *pp = 0;

    /* if containing ep undefined, look at its container */
    if (ep && ep->p.sys_type == EMPTY_PARTITION)
      ep = ep->ep;

    if (ep) {
	if (boxes == NESTED || (boxes == CHAINED && !is_extended))
	  pp = ep;
	else if (all_logicals_inside_outermost_extended)
	  pp = outer_extended_partition(ep);
    }
#if 0
    ff = pp ? (pp->start + unit - 1) / unit : 0;
#else
    /* rounding up wastes almost an entire cylinder - round down
       and leave it to compute_start_sect() to fix the difference */
    ff = pp ? pp->start / unit : 0;
#endif
    /* MBR and 1st sector of an extended partition are never free */
    if (unit == 1)
      ff++;

  again:
    for(pp = partitions; pp < partitions+pno; pp++) {
	if (!is_parent(pp, ep) && pp->size > 0) {
	    if ((partitions_in_order || pp->start / unit <= ff
		                     || (mid && pp->start / unit <= mid))
		&& (fff = (pp->start + pp->size + unit - 1) / unit) > ff) {
		ff = fff;
		goto again;
	    }
	}
    }

    return ff;
}

/* find the default value for <size> - assuming entire units */
static unsigned long
max_length(int pno, int is_extended, struct part_desc *ep, int format,
	   unsigned long start, struct disk_desc *z) {
    unsigned long fu;
    unsigned long unit = unitsize(format);
    struct part_desc *partitions = &(z->partitions[0]), *pp = 0;

    /* if containing ep undefined, look at its container */
    if (ep && ep->p.sys_type == EMPTY_PARTITION)
      ep = ep->ep;

    if (ep) {
	if (boxes == NESTED || (boxes == CHAINED && !is_extended))
	  pp = ep;
	else if (all_logicals_inside_outermost_extended)