part.c

操作系统源代码

/*	part 1.47 - Partition table editor		Author: Kees J. Bot
 *								13 Mar 1992
 * Needs about 22k heap+stack.
 */
#define nil 0
#include <sys/types.h>
#include <stdio.h>
#include <termcap.h>
#include <errno.h>
#include <unistd.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <fcntl.h>
#include <time.h>
#include <dirent.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/partition.h>
#include <ibm/partition.h>
#include <termios.h>

#if !__minix_vmd
#define div64u(i, j)	((i) / (j))
#endif

/* Template:
                      ----first----  --geom/last--  ------sectors-----
    Device             Cyl Head Sec   Cyl Head Sec      Base      Size       Kb
    /dev/hd0                          977    5  17
    /dev/hd0:2           0    0   2   976    4  16         2     83043    41521
Num Sort   Type
 1* hd1  81 MINIX        0    0   3    33    4   9         3      2880     1440
 2  hd2  81 MINIX       33    4  10   178    2   2      2883     12284     6142
 3  hd3  81 MINIX      178    2   3   976    4  16     15167     67878    33939
 4  hd4  00 None         0    0   0     0    0  -1         0         0        0

 */
#define MAXSIZE		99999999L	/* Will 100 G be enough this year? */
#define SECTOR_SIZE	512
#define DEV_FD0		0x200		/* Device number of /dev/fd0 */
#define DEV_HD0		0x300		/* Device number of /dev/hd0 */

#define arraysize(a)	(sizeof(a) / sizeof((a)[0]))
#define arraylimit(a)	((a) + arraysize(a))

void report(const char *label)
{
	fprintf(stderr, "part: %s: %s\n", label, strerror(errno));
}

void fatal(const char *label)
{
	report(label);
	exit(1);
}

struct termios termios;

void save_ttyflags(void)
/* Save tty attributes for later restoration. */
{
	if (tcgetattr(0, &termios) < 0) fatal("");
}

void restore_ttyflags(void)
/* Reset the tty flags to how we got 'em. */
{
	if (tcsetattr(0, TCSANOW, &termios) < 0) fatal("");
}

void tty_raw(void)
/* Set the terminal to raw mode, no signals, no echoing. */
{
	struct termios rawterm;

	rawterm= termios;
	rawterm.c_lflag &= ~(ICANON|ISIG|ECHO);
	rawterm.c_iflag &= ~(ICRNL);
	if (tcsetattr(0, TCSANOW, &rawterm) < 0) fatal("");
}

#define ctrl(c)		((c) == '?' ? '\177' : ((c) & '\37'))

char t_cd[16], t_cm[32], t_so[16], t_se[16], t_md[16], t_me[16];
int t_li, t_co;
#define STATUSROW	10

void init_tty(void)
/* Get terminal capabilities and set the tty to "editor" mode. */
{
	char *term;
	static char termbuf[1024];
	char *tp;

	if ((term= getenv("TERM")) == nil || tgetent(termbuf, term) != 1) {
		fprintf(stderr, "part: Can't get terminal capabilities\n");
		exit(1);
	}
	if (tgetstr("cd", (tp= t_cd, &tp)) == nil
				|| tgetstr("cm", (tp= t_cm, &tp)) == nil) {
		fprintf(stderr, "part: This terminal is too dumb\n");
		exit(1);
	}
	t_li= tgetnum("li");
	t_co= tgetnum("co");
	(void) tgetstr("so", (tp= t_so, &tp));
	(void) tgetstr("se", (tp= t_se, &tp));
	(void) tgetstr("md", (tp= t_md, &tp));
	(void) tgetstr("me", (tp= t_me, &tp));

	save_ttyflags();
	tty_raw();
}

void putchr(int c)
{
	putchar(c);
}

void putstr(char *s)
{
	int c;

	while ((c= *s++) != 0) putchr(c);
}

void set_cursor(int row, int col)
{
	tputs(tgoto(t_cm, col, row), 1, putchr);
}

int statusrow= STATUSROW;
int stat_ktl= 1;
int need_help= 1;

void stat_start(int serious)
/* Prepare for printing on a fresh status line, possibly highlighted. */
{
	set_cursor(statusrow++, 0);
	tputs(t_cd, 1, putchr);
	if (serious) tputs(t_so, 1, putchr);
}

void stat_end(int ktl)
/* Closing bracket for stat_start.  Sets "keystrokes to live" of message. */
{
	tputs(t_se, 1, putchr);
	stat_ktl= ktl;
	need_help= 1;
}

void stat_reset(void)
/* Reset the statusline pointer and clear old messages if expired. */
{
	if (stat_ktl > 0 && --stat_ktl == 0) {
		statusrow= STATUSROW;
		need_help= 1;
	}
	if (need_help && statusrow < (24-2)) {
		if (statusrow > STATUSROW) stat_start(0);
		stat_start(0);
		putstr(
"Type '+' or '-' to change, 'r' to read, '?' for more help, '!' for advice");
	}
	statusrow= STATUSROW;
	need_help= 0;
}

void clear_screen(void)
{
	set_cursor(0, 0);
	tputs(t_cd, 1, putchr);
	stat_ktl= 1;
	stat_reset();
}

void reset_tty(void)
/* Reset the tty to cooked mode. */
{
	restore_ttyflags();
	set_cursor(statusrow, 0);
	tputs(t_cd, 1, putchr);
}

void *alloc(size_t n)
{
	void *m;

	if ((m= malloc(n)) == nil) { reset_tty(); fatal(""); }

	return m;
}

#ifndef makedev		/* Missing in sys/types.h */
#define minor(dev)	(((dev) >> MINOR) & BYTE)
#define major(dev)	(((dev) >> MAJOR) & BYTE)
#define makedev(major, minor)	\
			((dev_t) (((major) << MAJOR) | ((minor) << MINOR)))
#endif

typedef enum parttype { DUNNO, SUBPART, PRIMARY } parttype_t;

typedef struct device {
	struct device *next, *prev;	/* Circular dequeue. */
	dev_t	rdev;			/* Device number (sorting only). */
	char	*name;			/* E.g. /dev/hd0 */
	char	*subname;		/* E.g. /dev/hd0:2 */
	char	part[6];		/* E.g. hd2a */
	parttype_t parttype;
} device_t;

device_t *firstdev= nil, *curdev;

void newdevice(char *name, int scanning)
/* Add a device to the device list.  If scanning is set then we are reading
 * /dev, so insert the device in device number order and make /dev/hd0 current.
 */
{
	device_t *new, *nextdev, *prevdev;
	char *base;
	int max, len;
	struct stat st;

	st.st_rdev= 0;
	if (scanning) {
		if (stat(name, &st) < 0 || !S_ISBLK(st.st_mode)) return;

		switch (major(st.st_rdev)) {
		case 0:
		case 1:
		case 15:
			return;
		case 2:
			if (minor(st.st_rdev) >= 4) return;
			break;
		default:
			if (minor(st.st_rdev) >= 0x80
					|| minor(st.st_rdev) % 5 != 0) return;
		}
		/* Interesting device found. */
	} else {
		(void) stat(name, &st);
	}

	new= alloc(sizeof(*new));
	new->rdev= st.st_rdev;
	new->name= alloc((strlen(name) + 1) * sizeof(new->name[0]));
	strcpy(new->name, name);
	new->subname= new->name;
	new->parttype= DUNNO;
	if (major(st.st_rdev) == major(DEV_FD0)) {
		new->parttype= SUBPART;
	} else
	if (st.st_rdev >= DEV_HD0 && minor(st.st_rdev) < 128
			&& minor(st.st_rdev) % 5 == 0) {
		new->parttype= PRIMARY;
	}
	if ((base= strrchr(name, '/')) == nil) base= name; else base++;
	max= new->parttype == SUBPART ? 4 : 5;
	len= strlen(base);
	strcpy(new->part, len < max ? base : base + len - max);

	if (firstdev == nil) {
		firstdev= new;
		new->next= new->prev= new;
		curdev= firstdev;
		return;
	}
	nextdev= firstdev;
	while (new->rdev >= nextdev->rdev
				&& (nextdev= nextdev->next) != firstdev) {}
	prevdev= nextdev->prev;
	new->next= nextdev;
	nextdev->prev= new;
	new->prev= prevdev;
	prevdev->next= new;

	if (new->rdev < firstdev->rdev) firstdev= new;
	if (new->rdev == DEV_HD0) curdev= new;
	if (curdev->rdev != DEV_HD0) curdev= firstdev;
}

void getdevices(void)
/* Get all block devices from /dev that look interesting. */
{
	DIR *d;
	struct dirent *e;
	char name[5 + NAME_MAX + 1];

	if ((d= opendir("/dev")) == nil) fatal("/dev");

	while ((e= readdir(d)) != nil) {
		strcpy(name, "/dev/");
		strcpy(name + 5, e->d_name);
		newdevice(name, 1);
	}
	(void) closedir(d);
}

/* One featureful master bootstrap. */
unsigned char bootstrap[] = {
0353,0001,0000,0061,0300,0216,0330,0216,0300,0372,0216,0320,0274,0000,0174,0373,
0275,0276,0007,0211,0346,0126,0277,0000,0006,0271,0000,0001,0374,0363,0245,0352,
0044,0006,0000,0000,0264,0002,0315,0026,0250,0010,0164,0033,0350,0071,0001,0174,
0007,0060,0344,0315,0026,0242,0205,0007,0054,0060,0074,0012,0163,0363,0120,0350,
0046,0001,0205,0007,0130,0353,0012,0240,0002,0006,0204,0300,0165,0003,0351,0147,
0000,0230,0262,0005,0366,0362,0262,0200,0000,0302,0210,0340,0120,0350,0234,0000,
0163,0003,0351,0147,0000,0130,0054,0001,0175,0003,0351,0141,0000,0276,0276,0175,
0211,0357,0271,0040,0000,0363,0245,0200,0301,0004,0211,0356,0215,0174,0020,0070,
0154,0004,0164,0016,0213,0135,0010,0053,0134,0010,0213,0135,0012,0033,0134,0012,
0163,0014,0212,0044,0206,0144,0020,0210,0044,0106,0071,0376,0162,0364,0211,0376,
0201,0376,0356,0007,0162,0326,0342,0322,0211,0356,0264,0020,0366,0344,0001,0306,
0200,0174,0004,0001,0162,0026,0353,0021,0204,0322,0175,0041,0211,0356,0200,0174,
0004,0000,0164,0013,0366,0004,0200,0164,0006,0350,0070,0000,0162,0053,0303,0203,
0306,0020,0201,0376,0376,0007,0162,0346,0350,0215,0000,0211,0007,0376,0302,0204,
0322,0174,0023,0315,0021,0321,0340,0321,0340,0200,0344,0003,0070,0342,0167,0355,
0350,0011,0000,0162,0350,0303,0350,0003,0000,0162,0146,0303,0211,0356,0214,0134,
0010,0214,0134,0012,0277,0003,0000,0122,0006,0127,0264,0010,0315,0023,0137,0007,
0200,0341,0077,0376,0306,0210,0310,0366,0346,0211,0303,0213,0104,0010,0213,0124,
0012,0367,0363,0222,0210,0325,0366,0361,0060,0322,0321,0352,0321,0352,0010,0342,
0210,0321,0376,0301,0132,0210,0306,0273,0000,0174,0270,0001,0002,0315,0023,0163,
0020,0200,0374,0200,0164,0011,0117,0174,0006,0060,0344,0315,0023,0163,0270,0371,
0303,0201,0076,0376,0175,0125,0252,0165,0001,0303,0350,0013,0000,0243,0007,0353,
0005,0350,0004,0000,0227,0007,0353,0376,0136,0255,0126,0211,0306,0254,0204,0300,
0164,0011,0264,0016,0273,0001,0000,0315,0020,0353,0362,0303,0057,0144,0145,0166,
0057,0150,0144,0077,0010,0000,0015,0012,0000,0116,0157,0156,0145,0040,0141,0143,
0164,0151,0166,0145,0015,0012,0000,0122,0145,0141,0144,0040,0145,0162,0162,0157,
0162,0040,0000,0116,0157,0164,0040,0142,0157,0157,0164,0141,0142,0154,0145,0040,
0000,0000,
};

int dirty= 0;
unsigned char bootblock[SECTOR_SIZE];
struct part_entry table[1 + NR_PARTITIONS];
int existing[1 + NR_PARTITIONS];
unsigned long offset= 0, extbase= 0, extsize;
int submerged= 0;
char sort_index[1 + NR_PARTITIONS];
unsigned cylinders= 1, heads= 1, sectors= 1, secpcyl= 1;
unsigned alt_cyls= 1, alt_heads= 1, alt_secs= 1;
int precise= 0;
int device= -1;

unsigned long sortbase(struct part_entry *pe)
{
	return pe->sysind == NO_PART ? -1 : pe->lowsec;
}

void sort(void)
/* Let the sort_index array show the order partitions are sorted in. */
{
	int i, j;
	int idx[1 + NR_PARTITIONS];

	for (i= 1; i <= NR_PARTITIONS; i++) idx[i]= i;

	for (i= 1; i <= NR_PARTITIONS; i++) {
		for (j= 1; j <= NR_PARTITIONS-1; j++) {
			int sj= idx[j], sj1= idx[j+1];

			if (sortbase(&table[sj]) > sortbase(&table[sj1])) {
				idx[j]= sj1;
				idx[j+1]= sj;
			}
		}
	}
	for (i= 1; i <= NR_PARTITIONS; i++) sort_index[idx[i]]= i;
}

void dos2chs(unsigned char *dos, unsigned *chs)
/* Extract cylinder, head and sector from the three bytes DOS uses to address
 * a sector.  Note that bits 8 & 9 of the cylinder number come from bit 6 & 7
 * of the sector byte.  The sector number is rebased to count from 0.
 */
{
	chs[0]= ((dos[1] & 0xC0) << 2) | dos[2];
	chs[1]= dos[0];
	chs[2]= (dos[1] & 0x3F) - 1;
}

void abs2dos(unsigned char *dos, unsigned long pos)
/* Translate a sector offset to three DOS bytes. */
{
	unsigned h, c, s;

	c= pos / secpcyl;
	h= (pos % secpcyl) / sectors;
	s= pos % sectors + 1;

	dos[0]= h;
	dos[1]= s | ((c >> 2) & 0xC0);
	dos[2]= c & 0xFF;
}

void recompute0(void)
/* Recompute the partition size for the device after a geometry change. */
{
	if (device < 0) {
		cylinders= heads= sectors= 1;
		memset(table, 0, sizeof(table));
	} else
	if (!precise && offset == 0) {
		table[0].lowsec= 0;
		table[0].size= (unsigned long) cylinders * heads * sectors;
	}
	table[0].sysind= device < 0 ? NO_PART : MINIX_PART;
	secpcyl= heads * sectors;
}

void guess_geometry(void)
/* With a bit of work one can deduce the disk geometry from the partition
 * table.  This may be necessary if the driver gets it wrong.  (If partition
 * tables didn't have C/H/S numbers we would not care at all...)
 */
{
	int i, n;
	struct part_entry *pe;
	unsigned chs[3];
	unsigned long sec;
	unsigned h, s;
	unsigned char HS[256][8];	/* Bit map off all possible H/S */

	alt_cyls= alt_heads= alt_secs= 0;

	/* Initially all possible H/S combinations are possible.  HS[h][0]
	 * bit 0 is used to rule out a head value.
	 */
	for (h= 1; h <= 255; h++) {
		for (s= 0; s < 8; s++) HS[h][s]= 0xFF;
	}

	for (i= 0; i < 2*NR_PARTITIONS; i++) {
		pe= &(table+1)[i >> 1];
		if (pe->sysind == NO_PART) continue;

		/* Get the end or start sector numbers (in that order). */
		if ((i & 1) == 0) {
			dos2chs(&pe->last_head, chs);
			sec= pe->lowsec + pe->size - 1;
		} else {
			dos2chs(&pe->start_head, chs);
			sec= pe->lowsec;
		}

		if (chs[0] >= alt_cyls) alt_cyls= chs[0]+1;

		/* Which H/S combinations can be ruled out? */
		for (h= 1; h <= 255; h++) {
			if (HS[h][0] == 0) continue;
			n = 0;
			for (s= 1; s <= 63; s++) {
				if ((chs[0] * h + chs[1]) * s + chs[2] != sec) {
					HS[h][s/8] &= ~(1 << (s%8));
				}
				if (HS[h][s/8] & (1 << (s%8))) n++;
			}
			if (n == 0) HS[h][0]= 0;
		}
	}

	/* See if only one remains. */
	i= 0;
	for (h= 1; h <= 255; h++) {
		if (HS[h][0] == 0) continue;
		for (s= 1; s <= 63; s++) {
			if (HS[h][s/8] & (1 << (s%8))) {
				i++;
				alt_heads= h;
				alt_secs= s;
			}
		}
	}

	/* Forget it if more than one choice... */
	if (i > 1) alt_cyls= alt_heads= alt_secs= 0;
}

void geometry(void)
/* Find out the geometry of the device by querying the driver, or by looking
 * at the partition table.  These numbers are crosschecked to make sure that
 * the geometry is correct.  Master bootstraps other than the Minix one use
 * the CHS numbers in the partition table to load the bootstrap of the active
 * partition.
 */
{
	struct stat dst;
	int err= 0;
	struct partition geometry;

	if (submerged) {
		/* Geometry already known. */
		sort();
		return;
	}
	precise= 0;
	cylinders= 0;
	recompute0();
	if (device < 0) return;

	/* Try to guess the geometry from the partition table. */
	guess_geometry();

	/* Try to get the geometry from the driver. */
	(void) fstat(device, &dst);

	if (S_ISBLK(dst.st_mode) || S_ISCHR(dst.st_mode)) {
		/* Try to get the drive's geometry from the driver. */

		if (ioctl(device, DIOCGETP, &geometry) < 0)
			err= errno;
		else {
			table[0].lowsec= div64u(geometry.base, SECTOR_SIZE);
			table[0].size= div64u(geometry.size, SECTOR_SIZE);
			cylinders= geometry.cylinders;
			heads= geometry.heads;