part.c

操作系统源代码

	if (ev != '<' || diving == nil) return;

	if (dirty) event(E_WRITE, op);
	if (dirty) return;
	if (device >= 0) { close(device); device= -1; }

	olddiv= diving;
	diving= olddiv->up;

	table[0]= olddiv->old0;

	free(curdev->subname);
	curdev->subname= olddiv->oldsubname;

	strcpy(curdev->part, olddiv->oldpart);
	curdev->parttype= olddiv->oldparttype;
	offset= olddiv->oldoffset;
	extbase= olddiv->oldextbase;

	free(olddiv);

	event('r', op);
	if (diving == nil) submerged= 0;	/* We surfaced. */
}

int seek_sector(int device, unsigned long sector)
/* Seek to the given sector. */
{
#if __minix_vmd
	if (fcntl(device, F_SEEK, mul64u(offset, SECTOR_SIZE)) == 0)
		return 0;
#endif
	if ((off_t)(offset * SECTOR_SIZE) / SECTOR_SIZE != sector) {
		errno= EINVAL;
		return -1;
	}
	if (lseek(device, (off_t) offset * SECTOR_SIZE, SEEK_SET) == -1)
		return -1;
	return 0;
}

void m_read(int ev, object_t *op)
/* Read the partition table from the current device. */
{
	int i, mode, n;
	struct part_entry *pe;

	if (ev != 'r' || device >= 0) return;

	/* Open() may cause kernel messages: */
	stat_start(0);
	fflush(stdout);

	if (((device= open(curdev->name, mode= O_RDWR|O_CREAT, 0666)) < 0
		    && (errno != EACCES
			|| (device= open(curdev->name, mode= O_RDONLY)) < 0))
		|| seek_sector(device, offset) < 0
	) {
		stat_start(1);
		printf("%s: %s", curdev->name, strerror(errno));
		stat_end(5);
		if (device >= 0) { close(device); device= -1; }
		return;
	}

	/* Assume up to five lines of kernel messages. */
	statusrow+= 5-1;
	stat_end(5);

	if (mode == O_RDONLY) {
		stat_start(1);
		printf("%s: Readonly", curdev->name);
		stat_end(5);
	}
	memset(bootblock, 0, sizeof(bootblock));

	n= read(device, bootblock, SECTOR_SIZE);

	if (n <= 0) stat_start(1);
	if (n < 0) {
		printf("%s: %s", curdev->name, strerror(errno));
		close(device);
		device= -1;
	} else
	if (n < SECTOR_SIZE) printf("%s: Unexpected EOF", curdev->subname);
	if (n <= 0) stat_end(5);

	if (n < SECTOR_SIZE) n= SECTOR_SIZE;

	memcpy(table+1, bootblock+PART_TABLE_OFF,
					NR_PARTITIONS * sizeof(table[1]));
	for (i= 1; i <= NR_PARTITIONS; i++) {
		if ((table[i].bootind & ~ACTIVE_FLAG) != 0) break;
	}
	if (i <= NR_PARTITIONS || bootblock[510] != 0x55
				|| bootblock[511] != 0xAA) {
		/* Invalid boot block, install bootstrap, wipe partition table.
		 */
		memset(bootblock, 0, sizeof(bootblock));
		memcpy(bootblock, (void *) bootstrap, sizeof(bootstrap));
		memset(table+1, 0, NR_PARTITIONS * sizeof(table[1]));
		stat_start(1);
		printf("%s: Invalid partition table (reset)", curdev->subname);
		stat_end(5);
	}

	/* Fix an extended partition table up to something mere mortals can
	 * understand.  Record already defined partitions.
	 */
	for (i= 1; i <= NR_PARTITIONS; i++) {
		pe= &table[i];
		if (extbase != 0 && pe->sysind != NO_PART)
			pe->lowsec+= pe->sysind == EXT_PART
						? extbase : offset;
		existing[i]= pe->sysind != NO_PART;
	}
	geometry();
	dirty= 0;

	/* Warn about grave dangers ahead. */
	if (extbase != 0) {
		stat_start(1);
		printf("Warning: You are in a DOS extended partition.");
		stat_end(5);
	}
}

void m_write(int ev, object_t *op)
/* Write the partition table back if modified. */
{
	int c;
	struct part_entry new_table[NR_PARTITIONS], *pe;

	if (ev != 'w' && ev != E_WRITE) return;
	if (device < 0) { dirty= 0; return; }
	if (!dirty) {
		if (ev == 'w') {
			stat_start(1);
			printf("%s is not changed, or has already been written",
							curdev->subname);
			stat_end(2);
		}
		return;
	}

	if (bootblock[510] != 0x55 || bootblock[511] != 0xAA) {
		/* Invalid boot block, warn user. */
		stat_start(1);
		printf("Warning: About to write a new table on %s",
							curdev->subname);
		stat_end(5);
	}
	if (extbase != 0) {
		/* Will this stop the luser?  Probably not... */
		stat_start(1);
		printf("You have changed a DOS extended partition.  Bad Idea.");
		stat_end(5);
	}
	stat_start(1);
	putstr("Save partition table? (y/n) ");
	fflush(stdout);

	while ((c= getchar()) != 'y' && c != 'n' && c != ctrl('?')) {}

	if (c == ctrl('?')) putstr("DEL"); else putchr(c);
	stat_end(5);
	if (c == 'n' && ev == E_WRITE) dirty= 0;
	if (c != 'y') return;

	memcpy(new_table, table+1, NR_PARTITIONS * sizeof(table[1]));
	for (pe= new_table; pe < new_table + NR_PARTITIONS; pe++) {
		if (pe->sysind == NO_PART) {
			memset(pe, 0, sizeof(*pe));
		} else {
			abs2dos(&pe->start_head, pe->lowsec);
			abs2dos(&pe->last_head, pe->lowsec + pe->size - 1);

			/* Fear and loathing time: */
			if (extbase != 0)
				pe->lowsec-= pe->sysind == EXT_PART
						? extbase : offset;
		}
	}
	memcpy(bootblock+PART_TABLE_OFF, new_table, sizeof(new_table));
	bootblock[510]= 0x55;
	bootblock[511]= 0xAA;

	if (seek_sector(device, offset) < 0
		|| write(device, bootblock, SECTOR_SIZE) < 0
	) {
		stat_start(1);
		printf("%s: %s", curdev->name, strerror(errno));
		stat_end(5);
		return;
	}
	dirty= 0;
}

void m_shell(int ev, object_t *op)
/* Shell escape, to do calculations for instance. */
{
	int r, pid, status;
	void (*sigint)(int), (*sigquit)(int), (*sigterm)(int);

	if (ev != 's') return;

	reset_tty();
	fflush(stdout);

	switch (pid= fork()) {
	case -1:
		stat_start(1);
		printf("can't fork: %s\n", strerror(errno));
		stat_end(3);
		break;
	case 0:
		if (device >= 0) (void) close(device);
		execl("/bin/sh", "sh", (char *) nil);
		r= errno;
		stat_start(1);
		printf("/bin/sh: %s\n", strerror(errno));
		stat_end(3);
		exit(127);
	}
	sigint= signal(SIGINT, SIG_IGN);
	sigquit= signal(SIGQUIT, SIG_IGN);
	sigterm= signal(SIGTERM, SIG_IGN);
	while (pid >= 0 && (r= wait(&status)) >= 0 && r != pid) {}
	(void) signal(SIGINT, sigint);
	(void) signal(SIGQUIT, sigquit);
	(void) signal(SIGTERM, sigterm);
	tty_raw();
	if (pid < 0)
		;
	else
	if (WIFEXITED(status) && WEXITSTATUS(status) == 127)
		stat_start(0);	/* Match the stat_start in the child. */
	else
		event(ctrl('L'), op);
}

void m_dump(int ev, object_t *op)
/* Raw dump of the partition table. */
{
	struct part_entry table[NR_PARTITIONS], *pe;
	int i;
	unsigned chs[3];

	if (ev != 'p' || device < 0) return;

	memcpy(table, bootblock+PART_TABLE_OFF,
					NR_PARTITIONS * sizeof(table[0]));
	for (i= 0; i < NR_PARTITIONS; i++) {
		pe= &table[i];
		stat_start(0);
		dos2chs(&pe->start_head, chs);
		printf("%2d%c      %02X%15d%5d%4d",
			i+1,
			pe->bootind & ACTIVE_FLAG ? '*' : ' ',
			pe->sysind,
			chs[0], chs[1], chs[2]);
		dos2chs(&pe->last_head, chs);
		printf("%6d%5d%4d%10lu%10ld%9lu",
			chs[0], chs[1], chs[2],
			pe->lowsec,
			howend == SIZE ? pe->size : pe->size + pe->lowsec - 1,
			pe->size / 2);
		stat_end(10);
	}
	stat_start(0);
	printf("(Raw dump of the original %.40s table)",
		curdev->subname);
	stat_end(10);
}

int quitting= 0;

void m_quit(int ev, object_t *op)
/* Write the partition table if modified and exit. */
{
	if (ev != 'q' && ev != 'x') return;

	quitting= 1;

	if (dirty) event(E_WRITE, op);
	if (dirty) quitting= 0;
}

void m_help(int ev, object_t *op)
/* For people without a clue; let's hope they can find the '?' key. */
{
	static struct help {
		char	*keys;
		char	*what;
	} help[]= {
	 { "? !",		 "This help / more advice!" },
	 { "+ - (= _ PgUp PgDn)","Select/increment/decrement/make active" },
	 { "0-9 (a-f)",		 "Enter value" },
	 { "hjkl (arrow keys)",	 "Move around" },
	 { "CTRL-K CTRL-J",	 "Move entry up/down" },
	 { "CTRL-L",		 "Redraw screen" },
	 { ">",			 "Start a subpartition table" },
	 { "<",			 "Back to the primary partition table" },
	 { "m",			 "Cycle through magic values" },
	 { "spacebar",		 "Show \"Size\" or \"Last\"" },
	 { "r w",		 "Read/write partition table" },
	 { "p s q x",		 "Raw dump / Shell escape / Quit / Exit" },
	 { "y n DEL",		 "Answer \"yes\", \"no\", \"cancel\"" },
	};
	static char *advice[] = {
"* Choose a disk with '+' and '-', then hit 'r'.",
"* To change any value: Move to it and use '+', '-' or type the desired value.",
"* To make a new partition:  Move over to the Size or Kb field of an unused",
"  partition and type the size.  Hit the 'm' key to pad the partition out to",
"  a cylinder boundary.  Hit 'm' again to pad it out to the end of the disk.",
"  You can hit 'm' more than once on a base or size field to see several",
"  interesting values go by.  Note: Other Operating Systems can be picky about",
"  partitions that are not padded to cylinder boundaries.  Look for highlighted",
"  head or sector numbers.",
"* To reuse a partition:  Change the type to MINIX.",
"* To delete a partition:  Type a zero in the hex Type field.",
"* To make a partition active:  Type '+' in the Num field.",
"* To study the list of keys:  Type '?'.",
	};

	if (ev == '?') {
		struct help *hp;

		for (hp= help; hp < arraylimit(help); hp++) {
			stat_start(0);
			printf("%-25s - %s", hp->keys, hp->what);
			stat_end(0);
		}
		stat_start(0);
		putstr("Things like ");
		putstr(t_so); putstr("this"); putstr(t_se);
		putstr(" must be checked, but ");
		putstr(t_md); putstr("this"); putstr(t_me);
		putstr(" is not really a problem");
		stat_end(0);
	} else
	if (ev == '!') {
		char **ap;

		for (ap= advice; ap < arraylimit(advice); ap++) {
			stat_start(0);
			putstr(*ap);
			stat_end(0);
		}
	}
}

void event(int ev, object_t *op)
/* Simply call all modifiers for an event, each one knows when to act. */
{
	m_help(ev, op);
	m_redraw(ev, op);
	m_toggle(ev, op);
	m_orientation(ev, op);
	m_move(ev, op);
	m_updown(ev, op);
	m_enter(ev, op);
	m_leave(ev, op);
	m_modify(ev, op);
	m_magic(ev, op);
	m_in(ev, op);
	m_out(ev, op);
	m_read(ev, op);
	m_write(ev, op);
	m_shell(ev, op);
	m_dump(ev, op);
	m_quit(ev, op);
}

int keypress(void)
/* Get a single keypress.  Translate compound keypresses (arrow keys) to
 * their simpler equivalents.
 */
{
	char ch;
	int c;
	int esc= 0;

	set_cursor(curobj->row, curobj->col);
	fflush(stdout);

	do {
		if (read(0, &ch, sizeof(ch)) < 0) fatal("stdin");
		c= (unsigned char) ch;
		switch (esc) {
		case 0:
			switch (c) {
			case ctrl('['):	esc= 1; break;
			case '_':	c= '-'; break;
			case '=':	c= '+'; break;
			}
			break;
		case 1:
			esc= c == '[' ? 2 : 0;
			break;
		case 2:
			switch (c) {
			case 'D':	c= 'h';	break;
			case 'B':	c= 'j';	break;
			case 'A':	c= 'k';	break;
			case 'C':	c= 'l';	break;
			case 'H':	c= 'H';	break;
			case 'U':
			case 'S':	c= '-';	break;
			case 'V':
			case 'T':	c= '+';	break;
			}
			/*FALL THROUGH*/
		default:
			esc= 0;
		}
	} while (esc > 0);

	switch (c) {
	case ctrl('B'):	c= 'h';	break;
	case ctrl('N'):	c= 'j';	break;
	case ctrl('P'):	c= 'k';	break;
	case ctrl('F'):	c= 'l';	break;
	}

	return c;
}

void mainloop(void)
/* Get keypress, handle event, display results, reset screen, ad infinitum. */
{
	int key;

	while (!quitting) {
		stat_reset();

		key= keypress();

		event(key, curobj);

		display();
	}
}

int main(int argc, char **argv)
{
	object_t *op;
	int i, r, key;
	struct part_entry *pe;

	/* Define a few objects to show on the screen.  First text: */
	op= newobject(O_INFO, 0, 0,  2, 19);
	op= newobject(O_TEXT, 0, 0, 22, 13); op->text= "----first----";
	op= newobject(O_TEXT, 0, 0, 37, 13); op->text= "--geom/last--";
	op= newobject(O_TEXT, 0, 0, 52, 18); op->text= "------sectors-----";
	op= newobject(O_TEXT, 0, 1,  4,  6); op->text= "Device";
	op= newobject(O_TEXT, 0, 1, 23, 12); op->text= "Cyl Head Sec";
	op= newobject(O_TEXT, 0, 1, 38, 12); op->text= "Cyl Head Sec";
	op= newobject(O_TEXT, 0, 1, 56,  4); op->text= "Base";
	op= newobject(O_TEXT, 0, 1, 66,  4); op->text= size_last;
	op= newobject(O_TEXT, 0, 1, 77,  2); op->text= "Kb";
	op= newobject(O_TEXT, 0, 4,  0, 15); op->text= "Num Sort   Type";

	/* The device is the current object: */
    curobj= newobject(O_DEV,  OF_MOD, 2,  4, 15);
	op= newobject(O_SUB,       0, 3,  4, 15);

	/* Geometry: */
	op= newobject(O_CYL,  OF_MOD, 2, 40,  4); op->entry= &table[0];
	op= newobject(O_HEAD, OF_MOD, 2, 45,  3); op->entry= &table[0];
	op= newobject(O_SEC,  OF_MOD, 2, 49,  2); op->entry= &table[0];

	/* Objects for the device: */
	op= newobject(O_SCYL,  0, 3, 25,  4); op->entry= &table[0];
	op= newobject(O_SHEAD, 0, 3, 30,  3); op->entry= &table[0];
	op= newobject(O_SSEC,  0, 3, 34,  2); op->entry= &table[0];
	op= newobject(O_LCYL,  0, 3, 40,  4); op->entry= &table[0];
	op= newobject(O_LHEAD, 0, 3, 45,  3); op->entry= &table[0];
	op= newobject(O_LSEC,  0, 3, 49,  2); op->entry= &table[0];
	op= newobject(O_BASE,  0, 3, 59,  8); op->entry= &table[0];
	op= newobject(O_SIZE,  0, 3, 69,  8); op->entry= &table[0];
	op= newobject(O_KB,    0, 3, 78,  8); op->entry= &table[0];

	/* Objects for each partition: */
	for (r= 5, pe= table+1; pe <= table+NR_PARTITIONS; r++, pe++) {
		op= newobject(O_NUM,    OF_MOD, r,  2,  2); op->entry= pe;
		op= newobject(O_SORT,        0, r,  3,  5); op->entry= pe;
		op= newobject(O_TYPHEX, OF_MOD, r, 10,  2); op->entry= pe;
		op= newobject(O_TYPTXT, OF_MOD, r, 12,  9); op->entry= pe;
		op= newobject(O_SCYL,   OF_MOD, r, 25,  4); op->entry= pe;
		op= newobject(O_SHEAD,  OF_MOD, r, 30,  3); op->entry= pe;
		op= newobject(O_SSEC,   OF_MOD, r, 34,  2); op->entry= pe;
		op= newobject(O_LCYL,   OF_MOD, r, 40,  4); op->entry= pe;
		op= newobject(O_LHEAD,  OF_MOD, r, 45,  3); op->entry= pe;
		op= newobject(O_LSEC,   OF_MOD, r, 49,  2); op->entry= pe;
		op= newobject(O_BASE,   OF_MOD, r, 59,  8); op->entry= pe;
		op= newobject(O_SIZE,   OF_MOD, r, 69,  8); op->entry= pe;
		op= newobject(O_KB,     OF_MOD, r, 78,  8); op->entry= pe;
	}

	for (i= 1; i < argc; i++) newdevice(argv[i], 0);

	if (firstdev == nil) {
		getdevices();
		key= ctrl('L');
	} else {
		key= 'r';
	}

	if (firstdev != nil) {
		init_tty();
		clear_screen();
		event(key, curobj);
		display();
		mainloop();
		reset_tty();
	}
	exit(0);
}