partition.c

LINUX lilo-22.7 源代码。

/* partition.c  -  Partition table handling */
/*
Copyright 1992-1998 Werner Almesberger.
Copyright 1999-2004 John Coffman.
All rights reserved.

Licensed under the terms contained in the file 'COPYING' in the 
source directory.

*/

#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <limits.h>
#include <time.h>
#include <dirent.h>
#include "config.h"
#include "lilo.h"
#include "common.h"
#include "cfg.h"
#include "device.h"
#include "geometry.h"
#include "partition.h"
#include "boot.h"
#include "loader.h"

#if __GLIBC__ < 2 || __GLIBC_MINOR__ < 1
#if defined(_syscall5) && defined(__NR__llseek)
       
       _syscall5(int,  _llseek,  unsigned int,  fd, unsigned int, hi,
           unsigned int, lo, lloff_t *, res, unsigned int, wh);
       int _llseek(unsigned int fd,  unsigned  int  offset_high,
           unsigned  int  offset_low,  lloff_t * result, unsigned int whence);

       lloff_t lseek64(unsigned int fd, lloff_t offs, unsigned int whence)
       { lloff_t res;
       	   return _llseek(fd, offs>>32, offs, &res, whence) < 0  ?
       			 (lloff_t)(-1) : res;
       }

#else
/* last ditch attempt on small disks, and very old systems */
# warning "*****************************************"
# warning "***** no 64 bit lseek is available ******"
# warning "***** using 23 bit sector addresses *****"
# warning "*****************************************"
# define lseek64 lseek
#endif
#endif

static
int anywhere(void *buf, unsigned char *str)
{
    int k, n;
    void *s;
    
    k = strlen(str);
    n = SECTOR_SIZE-k;
    s = memchr(buf, *str, n);
    while(s) {
	if (!strncmp(s, str, k)) return 1;
	s++;
	n = SECTOR_SIZE - k - (int)(s-buf);
	s = memchr(s, *str, n);
    }
    return 0;
}



/* identify partitions which would be destroyed if the boot block
   is overwritten:
   
   known problems occur for:
   	XFS
   	NTFS
   	DOS FAT (relocation will fix)

*/
int part_nowrite(char* device)
{
    int fd;
    BOOT_SECTOR bs;
    
    int ret=PTW_OKAY;	/* say ok, unless we recognize a problem partition */
if ( !(do_md_install && extra==X_MBR_ONLY) ) {
    if ((fd = open(device, O_RDONLY)) < 0) pdie("part_nowrite check:");
    if (read(fd, bs.sector, sizeof(bs)) != SECTOR_SIZE) pdie("part_nowrite: read:");
    
/* check for XFS */
    if (!strncmp("XFSB", bs.sector, 4)) ret=PTW_XFS;
    
/* check for NTFS */
    else if (	!strncmp("NTFS", bs.par_d.system, 4)
		|| anywhere(bs.sector,"NTLDR")  ) ret=PTW_NTFS;

/* check for HPFS */
    else if (	!strncmp("OS2", bs.par_d.system, 3)
		|| anywhere(bs.sector,"OS2LDR")  ) ret=PTW_OS2;

/* check for DOS FAT */
    else if (
	(bs.par_d.bpb.media_descriptor >= 0xF8 || bs.par_d.bpb.media_descriptor == 0xF0)
	&& *(short*)bs.par_d.bpb.bytes_per_sector == SECTOR_SIZE
	&& (bs.par_d.bpb.number_of_FATs==1 || bs.par_d.bpb.number_of_FATs==2)
    /* sectors_per_cluster is a power of 2, meaning only 1 bit is on */
	&& bs.par_d.bpb.sectors_per_cluster
	&& (bs.par_d.bpb.sectors_per_cluster & (bs.par_d.bpb.sectors_per_cluster-1))==0
				) {
		ret=PTW_DOS;
#if 0
/* this, it turns out is from Windows 98, so no caution here on NT */
    		if (anywhere(bs.sector,"WINBOOT SYS")) ret+=PTW_NTFS;
#endif
    }
    
/* check for SWAP -- last check, as 'bs' is overwritten */
    else if (*(int*)bs.sector == 0xFFFFFFFEU) {
	if (lseek(fd, (PAGE_SIZE)-SECTOR_SIZE, SEEK_SET) != (PAGE_SIZE)-SECTOR_SIZE)
	    pdie("part_nowrite lseek:");
	if (SECTOR_SIZE != read(fd, bs.sector, sizeof(bs)) ) pdie("part_nowrite swap check:");
	if (!strncmp(bs.sector+SECTOR_SIZE-10,"SWAPSPACE2",10)
	    || !strncmp(bs.sector+SECTOR_SIZE-10,"SWAP-SPACE",10) ) ret=PTW_SWAP;
    }

/* didn't recognize the superblock type, so assume it is okay */    
    else ret=PTW_OKAY;
    
    close(fd);

} /* raid install with X_MBR_ONLY in use */
    if (verbose>=6) printf("part_nowrite: %d\n", ret);    
    
    return ret;
}


void part_verify(int dev_nr,int type)
{
    GEOMETRY geo;
    DEVICE dev;
    char backup_file[PATH_MAX+1];
    int fd, bck_file, part, size, lin_3d, cyl;
    unsigned int second, base;
    struct partition part_table[PART_MAX];
    int mask, i, pe, Linux, dos, mbr;
    unsigned short boot_sig;
    BOOT_PARAMS_1 bs;
    
    if (!has_partitions(dev_nr) || !(mask = P_MASK(dev_nr)) || !(dev_nr & mask)
#if 0
     || (dev_nr & mask) > PART_MAX
#endif
     	) return;

    if (verbose >= 4) printf("part_verify:  dev_nr=%04x, type=%d\n", dev_nr, type);
    geo_get(&geo,dev_nr & ~mask,-1,1);
    fd = dev_open(&dev,dev_nr & ~mask,cfg_get_flag(cf_options,"fix-table")
      && !test ? O_RDWR : O_RDONLY);
    part = (pe = dev_nr & mask)-1;
#if 1
    if (type) {
	if (lseek(fd, 0L, SEEK_SET) != 0 ||
	    read(fd, &bs, sizeof(bs)) != sizeof(bs) ) pdie("bs read");
	if (*(int*)bs.signature==EX_MAG_HL) mbr = bs.stage;
	else mbr = STAGE_MBR;
    } else mbr = STAGE_MBR;
#endif
    if (lseek(fd, PART_TABLE_OFFSET, SEEK_SET) < 0) pdie("lseek partition table");
    if (!(size = read(fd,(char *) part_table, sizeof(struct partition)*
      PART_MAX))) die("Short read on partition table");
    if (size < 0) pdie("read partition table");
    if ( read(fd, &boot_sig, sizeof(boot_sig)) != sizeof(boot_sig)  ||
	boot_sig != BOOT_SIGNATURE ) die("read boot signature failed");

    if (verbose>=5) printf("part_verify:  part#=%d\n", pe);

    second=base=0;
    for (i=0; i<PART_MAX; i++) {
	if (is_extd_part(part_table[i].sys_ind)) {
	    if (!base) base = part_table[i].start_sect;
	    else die("invalid partition table: second extended partition found");
	}
    }
    i=5;
    while (i<=pe && base) {
        if (lseek64(fd, LLSECTORSIZE*(base+second) + PART_TABLE_OFFSET, SEEK_SET) < 0)
            die("secondary lseek64 failed");
	if (read(fd, part_table, sizeof(part_table)) != sizeof(part_table)) die("secondary read pt failed");
	if ( read(fd, &boot_sig, sizeof(boot_sig)) != sizeof(boot_sig)  ||
	    boot_sig != BOOT_SIGNATURE ) die("read second boot signature failed");
        if (is_extd_part(part_table[1].sys_ind)) second=part_table[1].start_sect;
        else base = 0;
        i++;
        part=0;
    }
#if 1
    if (type && pe>0 && pe<=(mbr==STAGE_MBR2?63:PART_MAX)
    	     && !(part_table[part].boot_ind&0x80) && !nowarn)
	fprintf(errstd,"Warning: Partition %d on %s is not marked Active.\n",
		pe, dev.name);
#endif
    i = part_table[part].sys_ind;

    Linux =   i == PART_LINUX_MINIX ||
	      i == PART_LINUX_NATIVE ||
	      is_extd_part(i);

    i &= ~HIDDEN_OFF;
    dos =     i == PART_DOS12 ||
	      i == PART_DOS16_SMALL ||
	      i == PART_DOS16_BIG ||
	      i == PART_FAT32 ||
	      i == PART_FAT32_LBA ||
	      i == PART_FAT16_LBA ;

    if (type && !Linux) {
	fflush(stdout);
	if (!nowarn) fprintf(errstd,"Warning: partition type 0x%02X"" on device 0x%04X is a dangerous place for\n"
							"    a boot sector.",
			part_table[part].sys_ind, dev_nr);
	if (dos && !nowarn) fprintf(errstd,"  A DOS/Windows/OS2 system may be rendered unbootable."
		"\n  The backup copy of this boot sector should be retained.");
	if (!nowarn) fprintf(errstd,"\n");
#if 0
	if (!dos && !cfg_get_flag(cf_options,"ignore-table"))
	    die("You may proceed by using either '-P ignore' or 'ignore-table'");
#else
	if (!yesno("\nProceed? ", 0)) exit(0);
#endif
    }
    cyl = part_table[part].cyl+((part_table[part].sector >> 6) << 8);
    lin_3d = (part_table[part].sector & 63)-1+(part_table[part].head+
      cyl*geo.heads)*geo.sectors;
    if (pe <= PART_MAX &&
	    (lin_3d > part_table[part].start_sect || (lin_3d <
	    part_table[part].start_sect && cyl != BIOS_MAX_CYLS-1)) &&
	    !nowarn) {
	fflush(stdout);
	fprintf(errstd,"Device 0x%04X: Inconsistent partition table, %d%s entry\n",
	  dev_nr & ~mask,part+1,!part ? "st" : part == 1 ? "nd" : part ==
	  2 ? "rd" : "th");
	fprintf(errstd,"  CHS address in PT:  %d:%d:%d  -->  LBA (%d)\n",
		cyl,
		part_table[part].head,
		part_table[part].sector & 63,
		lin_3d);
	cyl = part_table[part].start_sect/geo.sectors/geo.heads;
	fprintf(errstd,"  LBA address in PT:  %d  -->  CHS (%d:%d:%d)\n",
		part_table[part].start_sect,
		cyl,
		part_table[part].head = (part_table[part].start_sect/geo.sectors) % geo.heads,
		part_table[part].sector = (part_table[part].start_sect % geo.sectors)+1
		);
	if (cyl >= BIOS_MAX_CYLS) cyl = BIOS_MAX_CYLS-1;
	part_table[part].sector |= (cyl >> 8)<<6;
	part_table[part].cyl = cyl & 0xff;
	if (!cfg_get_flag(cf_options,"fix-table") && !cfg_get_flag(cf_options,
	  "ignore-table")) die("Either FIX-TABLE or IGNORE-TABLE must be specified\n"
			"If not sure, first try IGNORE-TABLE (-P ignore)");
	if (test || cfg_get_flag(cf_options,"ignore-table"))
	    fprintf(errstd,"The partition table is *NOT* being adjusted.\n");
	else {
	    sprintf(backup_file,BACKUP_DIR "/part.%04X",dev_nr & ~mask);
	    if ((bck_file = creat(backup_file,0644)) < 0)
		die("creat %s: %s",backup_file,strerror(errno));
	    if (!(size = write(bck_file,(char *) part_table,
	      sizeof(struct partition)*PART_MAX)))
		die("Short write on %s",backup_file);
	    if (size < 0) pdie(backup_file);
	    if (close(bck_file) < 0)
		die("close %s: %s",backup_file,strerror(errno));
	    if (verbose > 0)
		printf("Backup copy of partition table in %s\n",backup_file);
	    printf("Writing modified partition table to device 0x%04X\n",
	      dev_nr & ~mask);
	    if (lseek(fd,PART_TABLE_OFFSET,SEEK_SET) < 0)
		pdie("lseek partition table");
	    if (!(size = write(fd,(char *) part_table,sizeof(struct partition)*
	      PART_MAX))) die("Short write on partition table");
	    if (size < 0) pdie("write partition table");
	}
    }
    dev_close(&dev);
}


CHANGE_RULE *change_rules = NULL;


void do_cr_reset(void)
{
    CHANGE_RULE *next;

    while (change_rules) {
	next = change_rules->next;
	free((char *) change_rules->type);
	free(change_rules);
	change_rules = next;
    }
}


static unsigned char cvt_byte(const char *s)
{
    char *end;
    unsigned int value;

    value = strtoul(s,&end,0);
    if (value > 255 || *end) cfg_error("\"%s\" is not a byte value",s);
    return value;
}


static void add_type(const char *type,int normal,int hidden)
{
    CHANGE_RULE *rule;

    for (rule = change_rules; rule; rule = rule->next)
	if (!strcasecmp(rule->type,type))
	    die("Duplicate type name: \"%s\"",type);
    rule = alloc_t(CHANGE_RULE);
    rule->type = stralloc(type);
    rule->normal = normal == -1 ? hidden ^ HIDDEN_OFF : normal;
    rule->hidden = hidden == -1 ? normal ^ HIDDEN_OFF : hidden;
    rule->next = change_rules;
    change_rules = rule;
}


void do_cr_type(void)
{
    const char *normal,*hidden;

    cfg_init(cf_change_rule);
    (void) cfg_parse(cf_change_rule);
    normal = cfg_get_strg(cf_change_rule,"normal");
    hidden = cfg_get_strg(cf_change_rule,"hidden");
    if (normal)
	add_type(cfg_get_strg(cf_change_rules,"type"),cvt_byte(normal),
	  hidden ? cvt_byte(hidden) : -1);
    else {
	if (!hidden)
	    cfg_error("At least one of NORMAL and HIDDEN must be present");
	add_type(cfg_get_strg(cf_change_rules,"type"),cvt_byte(hidden),-1);
    }
    cfg_unset(cf_change_rules,"type");
}


void do_cr(void)
{
    cfg_init(cf_change_rules);
    (void) cfg_parse(cf_change_rules);
}


#if defined(LCF_REWRITE_TABLE) && !defined(LCF_READONLY)

/*
 * Rule format:
 *
 * +------+------+------+------+
 * |drive |offset|expect| set  |
 * +------+------+------+------+
 *     0      1      2      3
 */

static void add_rule(unsigned char bios,unsigned char offset,
  unsigned char expect,unsigned char set)
{
    int i;

    if (curr_prt_map == PRTMAP_SIZE)
	cfg_error("Too many change rules (more than %s)",PRTMAP_SIZE);
    if (verbose >= 3)
	printf("  Adding rule: disk 0x%02x, offset 0x%x, 0x%02x -> 0x%02x\n",
	    bios,PART_TABLE_OFFSET+offset,expect,set);
    prt_map[curr_prt_map] = (set << 24) | (expect << 16) | (offset << 8) | bios;
    for (i = 0; i < curr_prt_map; i++) {
	if (prt_map[i] == prt_map[curr_prt_map])
	  die("Repeated rule: disk 0x%02x, offset 0x%x, 0x%02x -> 0x%02x",
	    bios,PART_TABLE_OFFSET+offset,expect,set);
	if ((prt_map[i] & 0xffff) == ((offset << 8) | bios) &&
	  (prt_map[i] >> 24) == expect)
	    die("Redundant rule: disk 0x%02x, offset 0x%x: 0x%02x -> 0x%02x "
	      "-> 0x%02x",bios,PART_TABLE_OFFSET+offset,
	     (prt_map[i] >> 16) & 0xff,expect,set);
    }
    curr_prt_map++;
}

#endif


static int has_partition;

static CHANGE_RULE *may_change(unsigned char sys_ind)
{
    CHANGE_RULE *cr = change_rules;
    
    while (cr) {
        if (cr->normal == sys_ind || cr->hidden == sys_ind) return cr;
        cr = cr->next;
    }
    return NULL;
}