aosvs.c

给出了 zip 压缩算法的完整实现过程。

    if ((s.st_mode & S_IFDIR) != 0) {
      *a |= MSDOS_DIR_ATTR;
    }
  }
  if (n != NULL)
    *n = (s.st_mode & S_IFMT) == S_IFREG ? s.st_size : -1L;
  if (t != NULL) {
    t->atime = s.st_atime;
    t->mtime = s.st_mtime;
    t->ctime = s.st_ctime;
  }

  free(name);

  return unix2dostime(&s.st_ctime);
}

int deletedir(d)
char *d;
{
   return rmdir(d);
}

int set_extra_field(z, z_utim)
  struct zlist far *z;
  iztimes *z_utim;
  /* create extra field and change z->att if desired */
  /* NOTE: this AOS/VS version assumes the pathname in z->name is an
   * AOS/VS pathname, not a unix-style one.  Since you can zip up using
   * unix-style pathnames, this may create problems occasionally.
   * We COULD add code to parse back to AOS/VS format ...
   * (This might also fail for other reasons such as access denied, but
   * that should already have occurred.)
   * We set the central-dir extra fld pointer & length here to the same data.
   */
{
  int             aclend = 0;
/*
 * use this to simplify because different calls depending on
 * whether links are resolved
 */
  unsigned short  errc;

  z->ext = 0;               /* init to no extra field */
/* get the ?FSTAT info & the acl - if no errors, get memory & store.
 * (first, we have to cut off the trailing slash that was added if
 * it's a dir, since AOS/VS doesn't accept that kind of thing)
 */
  strncpy(znamebuf, z->name, $MXPL);
  znamebuf[$MXPL-1] = '\0';
  if (znamebuf[strlen(znamebuf)-1] == '/')
    znamebuf[strlen(znamebuf)-1] = '\0';
  if (linkput)
    errc = sys_fstat(znamebuf, BIT1, &(zzextrafld.fstat_packet));
  else
    errc = sys_fstat(znamebuf, 0, &(zzextrafld.fstat_packet));
  if (errc)
  {
    fprintf(stderr,
            "\n    Warning: can't get ?FSTAT info & acl of %s - error %d\n    ",
            znamebuf, errc);
    perror("sys_fstat()");
  }
  else
  {
    /* store the ACL - or, if a link (no ACL!), store the resolution name */
    if (zzextrafld.fstat_packet.norm_fstat_packet.styp_type != $FLNK)
    {
      if ((errc = sys_gacl(znamebuf, zzextrafld.aclbuf)) != 0)
      {
        fprintf(stderr, "\n    Warning: can't get acl of %s - error %d\n    ",
                z->name, errc);
        perror("sys_gacl()");
      }
      else
      {
        /* find length of ACL - ends with double-null */
        while (aclend++ < $MXACL  &&
               (zzextrafld.aclbuf[aclend - 1] != '\0'  ||
                zzextrafld.aclbuf[aclend] != '\0'))
          /* EMPTY LOOP */ ;
        if ((z->cextra = z->extra =
             malloc(sizeof(ZEXTRAFLD) - $MXACL + aclend + 4)) != NULL)
        {
          strncpy(zzextrafld.extra_header_id, ZEXTRA_HEADID,
                  sizeof(zzextrafld.extra_header_id));
          strncpy(zzextrafld.extra_sentinel, ZEXTRA_SENTINEL,
                  sizeof(zzextrafld.extra_sentinel));
          zzextrafld.extra_rev = ZEXTRA_REV;    /* this is a char, no need
                                                   to worry about byte order */
          /* set size (Intel (little-endian)) 2-byte int, which we've set
             as array to make it easier */
          errc = (unsigned short) (sizeof(ZEXTRAFLD) - $MXACL + aclend + 4 -
                                   sizeof(zzextrafld.extra_header_id) -
                                   sizeof(zzextrafld.extra_data_size));
          zzextrafld.extra_data_size[0] = errc & 0xFF;  /* low-order byte */
          zzextrafld.extra_data_size[1] = errc >> 8;    /* high-order byte */
          memcpy((char *) z->extra, (char *) &zzextrafld,
                 sizeof(ZEXTRAFLD) - $MXACL + aclend + 4);
          z->cext = z->ext = sizeof(ZEXTRAFLD) - $MXACL + aclend + 4;
        }
      }
    }
    else /* a link */
    {
      if ((errc = sys_glink(z->name, zzextrafld.aclbuf)) != 0)
      {
        fprintf(stderr,
              "\n    Warning: can't get link-resolution of %s - error %d\n    ",
                z->name, errc);
        perror("sys_glink()");
      }
      else
      {
        aclend = strlen(zzextrafld.aclbuf) + 1;
        if ((z->extra = malloc(sizeof(ZEXTRAFLD) - $MXACL + aclend + 4))
            != NULL)
        {
          strncpy(zzextrafld.extra_header_id, ZEXTRA_HEADID,
                  sizeof(zzextrafld.extra_header_id));
          strncpy(zzextrafld.extra_sentinel, ZEXTRA_SENTINEL,
                  sizeof(zzextrafld.extra_sentinel));
          zzextrafld.extra_rev = ZEXTRA_REV;    /* this is a char, no need
                                                   to worry about byte order */
          /* set size (Intel (little-endian)) 2-byte int, which we've set
             as array to make it easier */
          errc = (unsigned short) (sizeof(ZEXTRAFLD) - $MXACL + aclend + 4 -
                                   sizeof(zzextrafld.extra_header_id) -
                                   sizeof(zzextrafld.extra_data_size));
          zzextrafld.extra_data_size[0] = errc & 0xFF;  /* low-order byte */
          zzextrafld.extra_data_size[1] = errc >> 8;    /* high-order byte */
          memcpy((char *) z->extra, (char *) &zzextrafld,
                 sizeof(ZEXTRAFLD) - $MXACL + aclend + 4);
          z->ext = sizeof(ZEXTRAFLD) - $MXACL + aclend + 4;
        }
      }
    }
  }
  return ZE_OK;
}

#endif /* !UTIL */

void version_local()
{
    printf("Compiled with %s under %s.\n",
      "a C compiler",
      "AOS/VS"
    );
}


/*
 * This file defines for AOS/VS two Unix functions relating to links;
 * the calling code should have the following defines:
 *
 *    #define       lstat(path,buf)             zvs_lstat(path,buf)
 *    #define       readlink(path,buf,nbytes)   zvs_readlink(path,buf,nbytes)
 *
 * For these functions, I'm going to define yet 2 MORE filename buffers
 * and also insert code to change pathnames to Unix & back.  This is
 * easier than changing all the other places this kind of thing happens to
 * be efficient.  This is a kludge.  I'm also going to put the functions
 * here for my immediate convenience rather than somewhere else for
 * someone else's.
 *
 * WARNING: the use of static buffers means that you'd better get your
 * data out of these buffers before the next call to any of these functions!
 *
 */

/* =========================================================================
 * ZVS_LSTAT() - get (or simulate) stat information WITHOUT following symlinks
 *      This is intended to look to the outside like the unix lstat()
 *      function.  We do a quick-&-dirty filename conversion.
 *
 *      If the file is NOT a symbolic link, we can just do a stat() on it and
 *      that should be fine.  But if it IS a link, we have to set the elements
 *      of the stat struct ourselves, since AOS/VS doesn't have a built-in
 *      lstat() function.
 *
 *      RETURNS: 0 on success, or -1 otherwise
 *
 */

int zvs_lstat(char *path, struct stat *buf)
{
    char        *cp_vs = vsnamebuf;
    char        *cp_ux = path;
    int         mm, dd, yy;

    /*
     * Convert the Unix pathname to an AOS/VS pathname.
     * This is quick & dirty; it won't handle (for instance) pathnames with
     * ../ in the middle of them, and may choke on other Unixisms.  We hope
     * they're unlikely.
     */
    if (!strncmp(cp_ux, "../", 3))
    {
        *cp_vs++ = '^';        /* AOS/VS for ../ */
        cp_ux += 3;
    }
    else if (!strncmp(cp_ux, "./", 2))
    {
        *cp_vs++ = '=';        /* AOS/VS for ./ */
        cp_ux += 2;
    }

    do
    {
        if (*cp_ux == '/')
        {
            *cp_vs++ = ':';
        }
        else
        {
            *cp_vs++ = (char) toupper(*cp_ux);
        }

    } while (*cp_ux++ != '\0'  &&  cp_vs - vsnamebuf < sizeof(vsnamebuf));

    /* If Unix name was too long for our buffer, return an error return */
    if (cp_vs - vsnamebuf >= sizeof(vsnamebuf)  &&  *(cp_vs - 1) != '\0')
        return (-1);     /* error */

    /* Make AOS/VS ?FSTAT call that won't follow links & see if we find
     * anything.  If not, we return error.
     */
    if (sys_fstat(vsnamebuf,
                  BIT1,                 /* BIT1 says to not resolve links */
                  &vsfstatbuf))
        return (-1);     /* error */

    /* If we DID find the file but it's not a link,
     * call stat() and return its value.
     */
    if (vsfstatbuf.styp_type != $FLNK)
        return (stat(path, buf));        /* call with Unix pathname ... */

    /* Otherwise, we have to kludge up values for the stat structure */
    memset((char *) buf, 0, sizeof(*buf));   /* init to nulls (0 values) */
    buf->st_mode = S_IFLNK | 0777;           /* link and rwxrwxrwx */
    buf->st_uid = -1;                        /* this is what we get on AOS/VS
                                                anyway (maybe unless we set up
                                                a dummy password file?) */
    buf->st_nlink = 1;
    /* The DG date we've got is days since 12/31/67 and seconds/2.  So we
     * need to subtract 732 days (if that's not negative), convert to seconds,
     * and add adjusted seconds.
     */
    if (vsfstatbuf.stch.short_time[0] < 732)
        buf->st_ctime = buf->st_mtime = buf->st_atime = 0L;
    else
    {
        buf->st_ctime = buf->st_mtime = buf->st_atime =
                ((long) vsfstatbuf.stch.short_time[0] - 732L) * 24L * 3600L +
                2L * (long) vsfstatbuf.stch.short_time[1];
    }

    /* And we need to get the filename linked to and use its length as
     * the file size.  We'll use the Unix pathname buffer for this - hope
     * it's big enough.  (We won't overwrite anything, but we could get a
     * truncated path.)  If there's an error, here's our last chance to
     * say anything.
     */
    if ((buf->st_size = zvs_readlink(vsnamebuf, uxnamebuf, FNMAX)) < 0)
        return (-1);
    else
        return (0);

} /* end zvs_lstat() */

/* =========================================================================
 * ZVS_READLINK() - get pathname pointed to by an AOS/VS link file
 *      This is intended to look to the outside like the unix readlink()
 *      function.  We do a quick-&-dirty filename conversion.
 *
 *      RETURNS: the length of the output path (in bytes), or -1 if an error
 *
 */

int zvs_readlink(char *path, char *buf, int nbytes)
{
    char    *cp_vs = vsnamebuf;
    char    *cp_ux = buf;

    /* This is called with z->name, the filename the user gave, so we'll get
     * the link-resolution name on the assumption that it's a valid AOS/VS
     * name. We're also assuming a reasonable value (> 5) for nbytes.
     */
    if (sys_glink(path, vsnamebuf))
        return (-1);     /* readlink() is supposed to return -1 on error */

    /* Now, convert the AOS/VS pathname to a Unix pathname.
     * Note that sys_glink(), unlike readlink(), does add a null.
     */
    if (*cp_vs == '^')        /* AOS/VS for ../ */
    {
        strncpy(cp_ux, "../", 3);
        cp_ux += 3;
        cp_vs++;
    }
    else if (*cp_vs == '@')   /* AOS/VS for :PER:, kind of like /dev/ */
    {
        strncpy(cp_ux, "/PER/", 5);
        cp_ux += 5;
        cp_vs++;
    }
    else if (*cp_vs == '=')   /* AOS/VS for ./ */
    {
        strncpy(cp_ux, "./", 2);
        cp_ux += 2;
        cp_vs++;
    }
    while (*cp_vs != '\0'  &&  cp_ux - buf < nbytes)
    {
        if (*cp_vs == ':')
        {
            *cp_ux++ = '/';
        }
        else
        {
            *cp_ux++ = (char) toupper(*cp_vs);
        }
        cp_vs++;
    }

    return (cp_ux - buf);   /* # characters in Unix path (no trailing null) */

} /* end zvs_readlink() */