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13.1.c

/*
 * Sys V version
 *
 * Reads the i-node structures from a raw disk
 * device and then sums up the disk usage for
 * each user.  Prints out the number of blocks
 * each user is using.
 */
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/filsys.h>
#include <sys/inode.h>
#include <sys/ino.h>
#include <fcntl.h>
#include <stdio.h>
#include <pwd.h>

/*
 * Maximum user id.
 */
#ifndef MAXUID
#define MAXUID    32768
#endif

#define SBSIZE    BSIZE            /* size of super-block    */
#define sblock    sb_un.u_sblock

/*
 * The super-block.  We allow enough room for
 * a complete disk block.
 */
union {
    char    dummy[SBSIZE];
    struct  filsys u_sblock;
} sb_un;

int    nfiles;                     /* no. of files in filsys */

char   *pname;                     /* program name (argv[0]) */
char   *device;                    /* name of disk device    */
char   *filsys;                    /* name of file system    */

size_t blocks[MAXUID];             /* count of blocks used   */
struct dinode *dinode;             /* will hold the i-nodes  */

main(argc, argv)
int argc;
char **argv;
{
    int i, fd;
    register ino_t ino;
    register struct dinode *di;

    /*
     * Save the program name and check our arguments.
     */
    pname = *argv;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s raw-disk-device\n", pname);
        exit(1);
    }

    /*
     * Open the device for reading.
     */
    device = *++argv;

    if ((fd = open(device, O_RDONLY)) < 0) {
        perror(device);
        exit(1);
    }

    /*
     * Get the super-block from the device.
     */
    getsblock(fd);

    /*
     * Get the i-node structures from the device.
     */
    getinodes(fd);

    close(fd);

    /*
     * Zero the block counts.
     */
    for (i = 0; i < MAXUID; i++)
        blocks[i] = 0;

    /*
     * Add up the number of blocks being used by each
     * user id.
     */
    for (ino = 0; ino < nfiles; ino++) {
        /*
         * ROOTINO is the first i-node; skip any
         * before it.
         */
        if (ino < ROOTINO)
            continue;

        di = &dinode[ino];

        /*
         * If this is zero, the i-node is free (not
         * in use).
         */
        if ((di->di_mode & IFMT) == 0)
            continue;

        /*
         * Count the number of blocks being used by
         * this file. We round the number of bytes to
         * the next highest multiple of 512.
         */
        blocks[di->di_uid] += (di->di_size + 511) / 512;
    }

    /*
     * Print out what we added up.
     */
    printusage();
    exit(0);
}

/*
 * getsblock--get the super-block from the device referred
 *             to by fd.
 */
getsblock(fd)
int fd;
{
    /*
     * Make sure the disk information is current.  This
     * causes all disk writes to be scheduled.
     */
    sync();

    /*
     * Read in the super-block.  It is stored at file
     * system address SUPERBOFF.
     */
    lseek(fd, (long) SUPERBOFF, 0);
    read(fd, &sblock, SBSIZE);

    /*
     * The number of files (i-nodes) is calculated by
     * multiplying the number of blocks used to hold
     * i-nodes by the number of i-nodes in a block.
     */
    nfiles = sblock.s_isize * INOPB;

    /*
     * Save the name of the file system.
     */
    filsys = sblock.s_fname;
}

/*
 * getinodes--read in the i-node structures from the device
 *             referred to by fd.
 */
getinodes(fd)
int fd;
{
    register ino_t ino;
    register daddr_t iblk;
    struct dinode *malloc();

    /*
     * Allocate space for them all.
     */
    dinode = malloc(nfiles * sizeof(struct dinode));

    if (dinode == NULL) {
        fprintf(stderr, "%s: out of memory.\n", pname);
        exit(1);
    }

    /*
     * We read in i-nodes a disk block-full at a time.
     * The INOPB constant is the number of i-nodes in
     * a block.
     */
    for (ino = 0; ino < nfiles; ino += INOPB) {
        /*
         * The i-node's disk block number is given by
         * the itod macro.
         */
        iblk = itod(ino);

        /*
         * Read in this block of i-nodes.
         */
        bread(fd, iblk, &dinode[ino], BSIZE);
    }
}

/*
 * bread--read cnt bytes from fd into buf, starting at
 *         address bno.
 */
bread(fd, bno, buf, cnt)
daddr_t bno;
char *buf;
int cnt;
{
    int n;

    /*
     * Seek to the proper block.  The shifting by BSHIFT
     * converts the block number to a byte address.
     */
    lseek(fd, (long) (bno << BSHIFT), 0);

    /*
     * Read in the data.
     */
    if ((n = read(fd, buf, cnt)) != cnt) {
        perror(filsys);
        exit(1);
    }
}

/*
 * printusage--print out the disk usage in blocks.
 */
printusage()
{
    register int i;
    struct passwd *pwd;
    struct passwd *getpwuid();

    printf("%s (%s):\n", device, filsys);
    printf(" Blocks \t  User\n");

    for (i = 0; i < MAXUID; i++) {
        if (blocks[i] == 0)
            continue;

        /*
         * Look up the login name, and use it if
         * we find it.
         */
        if ((pwd = getpwuid(i)) != NULL)
            printf("%8d\t%s\n", blocks[i], pwd->pw_name);
        else
            printf("%8d\t#%d\n", blocks[i], i);
    }
}


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