misc.c

reiserfsprogs-3.6.19.tar.gz 源码 给有需要的人！

/* calculates number of blocks in a file. Returns 0 for "sparse"
   regular files and files other than regular files and block devices */
unsigned long count_blocks (char * filename, int blocksize)
{
    loff_t high, low;
    unsigned long sz;
    __u64 size;
    int fd;

    if (!S_ISBLK(misc_device_mode(filename)) && 
	!S_ISREG(misc_device_mode(filename)))
	return 0;

    fd = open (filename, O_RDONLY);
    if (fd == -1) {
	fprintf(stderr, "Failed to open '%s': %s.\n", filename, strerror(errno));
	return 0;
    }

#ifdef BLKGETSIZE64
    {
	if (ioctl (fd, BLKGETSIZE64, &size) >= 0) {
	    size = (size / MAX_BS) * MAX_BS / blocksize;
	    sz = size;
	    if ((__u64)sz != size)
		    die ("count_blocks: block device too large");

	    close(fd);
	    return sz;
	}
    }
#endif


#ifdef BLKGETSIZE
    {
	if (ioctl (fd, BLKGETSIZE, &sz) >= 0) {
	    size = sz;

	    close(fd);
	    return (size * 512 / MAX_BS) * MAX_BS / blocksize;
	}
    }
#endif

    low = 0;
    for( high = 1; valid_offset (fd, high); high *= 2 )
	low = high;
    while (low < high - 1) {
	const loff_t mid = ( low + high ) / 2;

	if (valid_offset (fd, mid))
	    low = mid;
	else
	    high = mid;
    }
    
    valid_offset (fd, 0);

    close (fd);
    return (low + 1) * MAX_BS / MAX_BS / blocksize;
}

/* there are masks for certain bits  */
__u16 mask16 (int from, int count)
{
    __u16 mask;


    mask = (0xffff >> from);
    mask <<= from;
    mask <<= (16 - from - count);
    mask >>= (16 - from - count);
    return mask;
}


__u32 mask32 (int from, int count)
{
    __u32 mask;


    mask = (0xffffffff >> from);
    mask <<= from;
    mask <<= (32 - from - count);
    mask >>= (32 - from - count);
    return mask;
}


__u64 mask64 (int from, int count)
{
    __u64 mask;


    mask = (0xffffffffffffffffLL >> from);
    mask <<= from;
    mask <<= (64 - from - count);
    mask >>= (64 - from - count);
    return mask;
}


__u32 get_random (void)
{
    srandom (time (0));
    return random ();
}

/* this implements binary search in the array 'base' among 'num' elements each
   of those is 'width' bytes long. 'comp_func' is used to compare keys */
int reiserfs_bin_search (void * key, void * base, __u32 num, int width,
			 __u32 * ppos, comparison_fn_t comp_func)
{
    __u32 rbound, lbound, j;
    int ret;

    if (num == 0 || base == NULL) {
	/* objectid map may be 0 elements long */
	*ppos = 0;
	return POSITION_NOT_FOUND;
    }

    lbound = 0;
    rbound = num - 1;

    for (j = (rbound + lbound) / 2; lbound <= rbound; j = (rbound + lbound) / 2) {
	ret =  comp_func ((void *)((char *)base + j * width), key ) ;
	if (ret < 0) { /* second is greater */
	    lbound = j + 1;
	    continue;

	} else if (ret > 0) { /* first is greater */
	    if (j == 0)
	    	break;
	    rbound = j - 1;
	    continue;
	} else { /* equal */
	    *ppos = j;
	    return POSITION_FOUND;
	}
    }

    *ppos = lbound;
    return POSITION_NOT_FOUND;
}


#define BLOCKLIST__ELEMENT_NUMBER 10

/*element is block number and device*/
int blockdev_list_compare (const void * block1, const void * block2) {
    if (*(__u32 *)block1 < *(__u32 *)block2)
        return -1;
    if (*(__u32 *)block1 > *(__u32 *)block2)
        return 1;
        
    if (*((__u32 *)block1 + 1) < *((__u32 *)block2 + 1))
        return -1;        
    if (*((__u32 *)block1 + 1) > *((__u32 *)block2 + 1))
        return 1;
        
    return 0;
}

void blocklist__insert_in_position (void *elem, void **base, __u32 *count, 
    int elem_size, __u32 *position) 
{
    if (elem_size == 0)
    	return;
    	
    if (*base == NULL)
        *base = getmem (BLOCKLIST__ELEMENT_NUMBER * elem_size);
    
    if (*count == get_mem_size((void *)*base) / elem_size)
        *base = expandmem (*base, get_mem_size((void *)*base), 
                        BLOCKLIST__ELEMENT_NUMBER * elem_size);
    
    if (*position < *count) {
        memmove (*base + (*position + 1), 
                 *base + (*position),
                 (*count - *position) * elem_size);
    }

    memcpy (*base + (char) *position * elem_size, elem, elem_size);
    *count+=1;
}

/* 0 - dma is not supported, scsi or regular file */
/* 1 - xt drive                                   */
/* 2 - ide drive */
static void get_dma_support(dma_info_t *dma_info){
    if (S_ISREG(dma_info->st.st_mode))
	dma_info->st.st_rdev = dma_info->st.st_dev;

    if (IDE_DISK_MAJOR(major(dma_info->st.st_rdev))) {
        dma_info->support_type = 2;
	return;
    }
    
#ifdef XT_DISK_MAJOR
    if (major(dma_info->st.st_rdev) == XT_DISK_MAJOR) {
	dma_info->support_type = 1;
	return;
    }
#endif    
    dma_info->support_type = 0;
}

/* 
 * Return values: 
 * 0 - ok;
 * 1 - preparation cannot be done 
 * -1 - preparation failed
 */

int prepare_dma_check(dma_info_t *dma_info) {
    DIR *dir;
    struct dirent *dirent;
    struct stat st;
    dev_t rdev;
    int rem;
    char buf[256];

#ifndef HDIO_GET_DMA
        return -1;
#endif
	
    if (fstat(dma_info->fd, &dma_info->st))
	die("stat on device failed\n");
   
    get_dma_support(dma_info);
   
    /* dma should be supported */
    if (dma_info->support_type == 0)
	return 1;
    
    if (dma_info->support_type == 2) {
	rdev = dma_info->st.st_rdev;

	if ((rem = (minor(rdev) % 64)) != 0) {
	    rdev -= rem;
	    if(!(dir = opendir("/dev/"))) {
		dma_info->support_type = 1;
		return 0;
	    }
	    
	    while ((dirent = readdir(dir)) != NULL) {
		if (strncmp(dirent->d_name, ".", 1) == 0 || strncmp(dirent->d_name, "..", 2) == 0)
		    continue;
		memset(buf, 0, 256);
		strncat(buf, "/dev/", 5);
		strncat(buf, dirent->d_name, strlen(dirent->d_name));
		
		if (stat(buf, &st))
		    break;
		
		if (S_ISBLK(st.st_mode) && st.st_rdev == rdev) 
		{
		    dma_info->st = st;
		    dma_info->fd = open(buf, O_RDONLY
#if defined(O_LARGEFILE)
					| O_LARGEFILE
#endif
					);
		    closedir(dir);
		    return 0;
		}
	    }
	    closedir(dir);
	    dma_info->support_type = 1;
	    return 1;
	}
    }
    
    return 0;
}

static int is_dma_on (int fd) {
#ifdef HDIO_GET_DMA    
    static long parm;
    if (ioctl(fd, HDIO_GET_DMA, &parm))
	return -1;
    else 
	return parm;
#endif
    return 0;
}


static __u64 dma_speed(int fd, int support_type) {
    static struct hd_driveid id;
    __u64 speed = 0;
            
    if (support_type != 2) 
	return 0;

#ifdef HDIO_OBSOLETE_IDENTITY
    if (!ioctl(fd, HDIO_GET_IDENTITY, &id) || 
	!ioctl(fd, HDIO_OBSOLETE_IDENTITY)) {
#else
    if (!ioctl(fd, HDIO_GET_IDENTITY, &id)) {
#endif
	speed |= (__u64)id.dma_1word &  ~(__u64)0xff;
	speed |= ((__u64)id.dma_mword & ~(__u64)0xff) << 16;
	speed |= ((__u64)id.dma_ultra & ~(__u64)0xff) << 32;
    } else if (errno == -ENOMSG)
	return -1;
    else 
	return -1;
    
    return speed;
}

int get_dma_info(dma_info_t *dma_info) {
    if ((dma_info->dma = is_dma_on(dma_info->fd)) == -1)
	return -1;
    if ((dma_info->speed = dma_speed(dma_info->fd, dma_info->support_type)) == (__u64)-1) 
	return -1;
    return 0;
}

void clean_after_dma_check(int fd, dma_info_t *dma_info) {
    signal(SIGALRM, SIG_IGN);
    if (dma_info->fd && fd != dma_info->fd)
	close(dma_info->fd);
}

/* Only le bitops operations are used. */

inline int misc_set_bit (unsigned long long nr, void * addr) {
    __u8 * p, mask;
    int retval;

    p = (__u8 *)addr;
    p += nr >> 3;
    mask = 1 << (nr & 0x7);
    /*cli();*/
    retval = (mask & *p) != 0;
    *p |= mask;
    /*sti();*/
    return retval;
}


inline int misc_clear_bit (unsigned long long nr, void * addr) {
    __u8 * p, mask;
    int retval;

    p = (__u8 *)addr;
    p += nr >> 3;
    mask = 1 << (nr & 0x7);
    /*cli();*/
    retval = (mask & *p) != 0;
    *p &= ~mask;
    /*sti();*/
    return retval;
}

inline int misc_test_bit(unsigned long long nr, const void * addr) {
    __u8 * p, mask;

    p = (__u8 *)addr;
    p += nr >> 3;
    mask = 1 << (nr & 0x7);
    return ((mask & *p) != 0);
}

inline unsigned long long misc_find_first_zero_bit (const void *vaddr, 
    unsigned long long size) 
{
    const __u8 *p = vaddr, *addr = vaddr;
    unsigned long long res;

    if (!size)
        return 0;

    size = (size >> 3) + ((size & 0x7) > 0);
    while (*p++ == 255) {
        if (--size == 0)
            return (unsigned long long)(p - addr) << 3;
    }

    --p;
    for (res = 0; res < 8; res++)
        if (!misc_test_bit (res, p))
            break;
    return res + (p - addr) * 8;
}


inline unsigned long long misc_find_next_zero_bit (const void *vaddr, 
    unsigned long long size, unsigned long long offset) 
{
    const __u8 *addr = vaddr;
    const __u8 *p = addr + (offset >> 3);
    int bit = offset & 7;
    unsigned long long res;

    if (offset >= size)
        return size;

    if (bit) {
        /* Look for zero in first char */
        for (res = bit; res < 8; res++)
            if (!misc_test_bit (res, p))
                return res + (p - addr) * 8;
        p++;
    }
    /* No zero yet, search remaining full bytes for a zero */
    res = misc_find_first_zero_bit (p, size - 8 * (p - addr));
    return res + (p - addr) * 8;
}

inline unsigned long long misc_find_first_set_bit (const void *vaddr, 
    unsigned long long size) 
{
    const __u8 *p = vaddr, *addr = vaddr;
    unsigned long long res;

    if (!size)
        return 0;

    size = (size >> 3) + ((size & 0x7) > 0);
    while (*p++ == 0) {
        if (--size == 0)
            return (unsigned long long)(p - addr) << 3;
    }

    --p;
    for (res = 0; res < 8; res++)
        if (misc_test_bit (res, p))
            break;

    return res + (p - addr) * 8;
}

inline unsigned long long misc_find_next_set_bit(const void *vaddr, 
    unsigned long long size, unsigned long long offset)
{
    const __u8 *addr = vaddr;
    const __u8 *p = addr + (offset >> 3);
    int bit = offset & 7;
    unsigned long long res;

    if (offset >= size)
        return size;

    if (bit) {
        /* Look for zero in first char */
        for (res = bit; res < 8; res++)
            if (misc_test_bit (res, p))
                return res + (p - addr) * 8;
        p++;
    }
    /* No set bit yet, search remaining full bytes for a 1 */
    res = misc_find_first_set_bit (p, size - 8 * (p - addr));
    return res + (p - addr) * 8;
}

#include "credits.h"

/* Reads the "CREDITS" file and prints one paragraph from it. */
void misc_print_credit(FILE *out) {
    char *line;
    __u32 num1, num2;
    
    fprintf(out, "A pair of credits:\n");
    
    srandom (time (0));
    
    num1 = random() % CREDITS_COUNT;
    line = credits[num1];
    fprintf(out, "%s\n", line);
    
    while ((num1 == (num2 = random() % CREDITS_COUNT))) {}
    
    line = credits[num2];
    
    fprintf(out, "%s\n", line);
}

int user_confirmed (FILE * fp, char * q, char * yes) {
    char * answer = 0;
    size_t n = 0;

    fprintf (fp, "%s", q);
    if (getline (&answer, &n, stdin) != (ssize_t)strlen (yes) || strcmp (yes, answer))
	return 0;

    return 1;
}