dollar_vars.c

Solaris操作系统下的过滤驱动程序, C源码程序.

/*
 * Copyright (c) 1997-2003 Erez Zadok
 * Copyright (c) 2001-2003 Stony Brook University
 * Copyright (c) 1997-2000 Columbia University
 *
 * For specific licensing information, see the COPYING file distributed with
 * this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
 *
 * This Copyright notice must be kept intact and distributed with all
 * fistgen sources INCLUDING sources generated by fistgen.
 */
/*
 * dollar_vars.c: validate/expand dollar variable names to their values
 * Fistgen sources.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */


/****************************************************************************/
char *valid_dollar_vargs[] = {
  "this",
  "dir",
  "from",
  "to",
  "fromdir",
  "todir",
  "vfs",
  NULL				/* must be last entry */
};

/*
 * List of static vnode attributes.  Others can be defined dynamically
 * using the %pervfs and %pervnode declarations.
 */

char *valid_dollar_vnode_attrs[] = {
  "ext",
  "name",
  "symlinkval",
  "type",
  /* the rest are stat(2) like attributes */
  "atime",
  "blocks",
  "ctime",
  "group",
  "mode",
  "mtime",
  "nlink",
  "size",
  "owner",			/* was "user" */
  "inum",			/* inode/vnode number */
  NULL				/* must be last entry */
};

/* list of common VFS attributes */
static fword_exp_fxn_t valid_dollar_vfs_attrs[] = {
  {"blocksize",		NULL},
  {"fstype",		NULL},	/* F/S type: wrapfs, nfs, ext2fs, etc. */
  /* add "bitsize" (32/64) */
  {NULL,		NULL}	/* must be last entry */
};


/****************************************************************************/

/*
 * Validate that a $varg is a valid v-arg keyword.
 * Return TRUE/FALSE.
 */
static int
fist_validate_dollar_varg(const char *str, char *errmsg)
{
  char **tmp = valid_dollar_vargs;

  /* NULL is valid $varg.  It means "this." */
  if (!str)
    return TRUE;

  if (!str[0])
    return FALSE;

  while (*tmp) {
    if (STREQ(*tmp, str))
      return TRUE;
    tmp++;
  }
  return FALSE;
}


/*
 * Validate that 'num' is within the valid range.
 * Return TRUE/FALSE.
 */
static int
fist_validate_dollar_num(const char *str, char *errmsg)
{
  int i;

  /* NULL is valid 'num'.  It means "0". */
  if (!str)
    return TRUE;

  if (!str[0])
    return FALSE;

  i = atoi(str);
  if (i < 0) {
    sprintf(errmsg, "negative/illegal $%d value", i);
    return FALSE;
  }
  if (i > MAX_FAN_OUT) {
    sprintf(errmsg, "$%d value exceeds MAX_FAN_OUT (%d)", i, MAX_FAN_OUT);
    return FALSE;
  }
  if (i > fist_globals.fg_fanout) {
    sprintf(errmsg, "$%d value exceeds fanout level (%d)",
	    i, fist_globals.fg_fanout);
    return FALSE;
  }

  return TRUE;			/* all OK */
}


/*
 * Validate that a vnode 'attr' is a valid attribute keyword.
 * Return TRUE/FALSE.
 */
static int
fist_validate_dollar_vnode_attr(const char *str, char *errmsg)
{
  char **tmp = valid_dollar_vnode_attrs;

  /* NULL is valid 'attr' */
  if (!str)
    return TRUE;

  if (!str[0])
    return FALSE;

  /* search for standard attributes */
  while (*tmp) {
    if (STREQ(*tmp, str))
      return TRUE;
    tmp++;
  }

  /* search in per-vnode attributes */
  if (fist_search_bdt(str, fist_globals.fg_pervnode))
    return TRUE;

  strcpy(errmsg, "invalid vnode attribute");
  return FALSE;
}


/*
 * Validate that a VFS 'attr' is a valid attribute keyword.
 * Return TRUE/FALSE.
 */
static int
fist_validate_dollar_vfs_attr(const char *str, char *errmsg)
{
  fword_exp_fxn_t *efp;

  /* NULL is valid 'attr' */
  if (!str)
    return TRUE;

  if (!str[0])
    return FALSE;

  /* search for standard attributes */
  for (efp = valid_dollar_vfs_attrs; efp->name; efp++)
    if (STREQ(str, efp->name))
      return TRUE;

  /* search in per-VFS attributes */
  if (fist_search_bdt(str, fist_globals.fg_pervfs))
    return TRUE;

  strcpy(errmsg, "invalid VFS attribute");
  return FALSE;
}


/*
 * Validate that a $something is a valid dollar variable.
 * Return TRUE/FALSE.
 */
int
fist_validate_dollar_variable(const char *str, const char *dv, const char *dn, const char *da, char *errmsg)
{
  strcpy(errmsg, "unknown FiST dollar variable"); /* default error */

  if (!str || !str[0] || !str[1])
    return FALSE;

  /* validate varg */
  if (!fist_validate_dollar_varg(dv, errmsg))
    return FALSE;

  /* validate num */
  if (!fist_validate_dollar_num(dn, errmsg))
    return FALSE;

  /* validate attr */
  if (dv && STREQ(dv, "vfs")) {
    if (!fist_validate_dollar_vfs_attr(da, errmsg))
      return FALSE;
  } else {
    if (!fist_validate_dollar_vnode_attr(da, errmsg))
      return FALSE;
  }

  /* all ok */
  return TRUE;
}


/****************************************************************************/
/*** FUNCTIONS TO EXPAND DOLLAR VARIABLES				  ***/
/****************************************************************************/

/*
 * Static expand $vfs with a given fanout number (dn) and attribute name (da)
 * Both dn and da may be NULL, but everything is valid.
 */
static void
expand_dollar_vfs(const char *dn, const char *da, char *buf)
{
  fword_exp_fxn_t *efp;

  /* simple case: wants back the vfs */
  if (!dn && !da) {
    strcpy(buf, "this_vfs");
    return;
  }

  /* no explicit fanout (n=1): wants vfs attribute or pervfs attribute */
  if (!dn) {
    /* search for normal attributes */
    for (efp = valid_dollar_vfs_attrs; efp->name; efp++) {
      if (STREQ(da, efp->name)) {
	if (efp->func)
	  (efp->func)(buf, NULL);
	else
	  sprintf(buf, "unimplemented_dollar_vfs(%s,%s)", dn, da);
	return;
      }
    }
    /* search for pervfs attributes */
    if (fist_search_bdt(da, fist_globals.fg_pervfs)) {
      sprintf(buf, "vfs2priv(this_vfs)->%s", da);
      return;
    }
  }

  /* if nothing matched, enclose string in "unknown" params */
  sprintf(buf, "unknown_dollar_vfs(%s,%s)", dn, da);
  return;
}


/*
 * Expand a dollar variable into its value.
 * Note: value returned is a static variable.
 * If cannot expand value, leaves it the same.
 * var: full string
 * dv: variable portion of var
 * dn: fanout number
 * da: attribute of var
 */
const char *
expand_dollar_var(const char *var, const char *dv, const char *dn, const char *da)
{
  static char buf[MAX_BUF_LEN];
  char vnode_name[MAX_BUF_LEN];
  int n = 0;

  if (dn)
    n = atoi(dn);
  if (dv && STREQ(dv, "vfs")) {
    expand_dollar_vfs(dn, da, buf);
    return buf;
  }

  /* process vnode names and fan-outs (lower vnodes) */
  strcpy(vnode_name, "unknown_vnode"); /* default */
  if (!dv)
    strcpy(vnode_name, "this_vnode");
  else {
    if (STREQ(dv, "dir")) {
      strcpy(vnode_name, "this_dir");
    }
    /* fill in for other names */
  }
  if (dn) {
    if (STREQ(dn, "1")) {
      sprintf(buf, "%s2lower(%s)",
	      (dv && STREQ(dv, "dir")) ? "dir" : "vnode",
	      vnode_name);
      strcpy(vnode_name, buf);
    }
  }
  if (da && dv && STREQ(dv, "dir"))
    strcat(vnode_name, FIST_DIR_TO_VNODE);
  if (!da) {
    strcpy(buf, vnode_name);
    return buf;
  }

  /*
   * If got here, then dealing with vnode attributes.
   */
  /* inode number */
  if (STREQ(da, "inum")) {
#ifdef __linux__
    sprintf(buf, "%s->%s", vnode_name, FIST_DA_INUM);
#else /* not __linux__ */
    char name[MAX_BUF_LEN], fxnbuf[MAX_BUF_LEN];

    /* form name of special getattr function */
    sprintf(name, "fist_getattr_%s", da);
    /* replace function with code */
    sprintf(buf, "%s(%s, cr)", name, vnode_name);
    /* check if support function is needed */
#ifdef __solaris__
    if (!fist_search_bdt(name, auto_generated_functions)) {
      /* XXX: on Solaris, inums are 64-bit. We cast to 32 bits */
      sprintf(fxnbuf, "unsigned long
%s(vnode_t *vp, cred_t *cr)\n{
  vattr_t va;
  int err;

  va.va_mask = AT_ALL;
  err = VOP_GETATTR(vp, &va, 0, cr);
  if (err)
    return -1;
  return (unsigned long) va.va_nodeid;
}", name);
#endif /* __solaris__ */
#ifdef __freebsd__
    if (!fist_search_bdt(name, auto_generated_functions)) {
      sprintf(fxnbuf, "unsigned long
%s(vnode_t *vp, cred_t *cr)\n{
  vattr_t va;
  int err;

  VATTR_NULL(&va);
  err = VOP_GETATTR(vp, &va, cr, curproc);
  if (err)
    return -1;
  return (unsigned long) va.va_fileid;
}", name);
#endif /* __freebsd__ */
      if (!append_to_bdt(&auto_generated_functions, fxnbuf, name)) {
	sprintf(buf, "cannot store getattr function %s", name);
	return buf;
      }
      /* side effect: append "extern" definition to fist header file */
      sprintf(fxnbuf, "extern unsigned long %s(vnode_t *vp, cred_t *cr);\n", name);
      if (!ecl_strcat(&auto_generated_externs, fxnbuf)) {
	sprintf(buf, "cannot store getattr extern definition %s", name);
	return buf;
      }
    }
#endif /* not __linux__ */
    return buf;
  }

  /* file owner */
  if (STREQ(da, "owner")) {
#ifdef __linux__
    sprintf(buf, "%s->%s", vnode_name, FIST_DA_USER);
#else /* not __linux__ */
    char name[MAX_BUF_LEN], fxnbuf[MAX_BUF_LEN];

    /* form name of special getattr function */
    sprintf(name, "fist_getattr_%s", da);
    /* replace function with code */
    sprintf(buf, "%s(%s, cr)", name, vnode_name);
    /* check if support function is needed */
#ifdef __solaris__
    if (!fist_search_bdt(name, auto_generated_functions)) {
      sprintf(fxnbuf, "uid_t
%s(vnode_t *vp, cred_t *cr)\n{
  vattr_t va;
  int err;

  va.va_mask = AT_ALL;
  err = VOP_GETATTR(vp, &va, 0, cr);
  if (err)
    return -1;
  return va.va_uid;
}", name);
#endif /* __solaris__ */
#ifdef __freebsd__
    if (!fist_search_bdt(name, auto_generated_functions)) {
      sprintf(fxnbuf, "uid_t
%s(vnode_t *vp, cred_t *cr)\n{
  vattr_t va;
  int err;

  VATTR_NULL(&va);
  err = VOP_GETATTR(vp, &va, cr, curproc);
  if (err)
    return -1;
  return va.va_uid;
}", name);
#endif /* __freebsd__ */
      if (!append_to_bdt(&auto_generated_functions, fxnbuf, name)) {
	sprintf(buf, "cannot store getattr function %s", name);
	return buf;
      }
      /* side effect: append "extern" definition to fist header file */
      sprintf(fxnbuf, "extern uid_t %s(vnode_t *vp, cred_t *cr);\n", name);
      if (!ecl_strcat(&auto_generated_externs, fxnbuf)) {
	sprintf(buf, "cannot store getattr extern definition %s", name);
	return buf;
      }
    }
#endif /* not __linux__ */
    return buf;
  }

  /* file group */
  if (STREQ(da, "group")) {
#ifdef __linux__
    sprintf(buf, "%s->%s", vnode_name, FIST_DA_GROUP);
#else /* not __linux__ */
    char name[MAX_BUF_LEN], fxnbuf[MAX_BUF_LEN];

    /* form name of special getattr function */
    sprintf(name, "fist_getattr_%s", da);
    /* replace function with code */
    sprintf(buf, "%s(%s, cr)", name, vnode_name);
    /* check if support function is needed */
#ifdef __solaris__
    if (!fist_search_bdt(name, auto_generated_functions)) {
      sprintf(fxnbuf, "gid_t
%s(vnode_t *vp, cred_t *cr)\n{
  vattr_t va;
  int err;

  va.va_mask = AT_ALL;
  err = VOP_GETATTR(vp, &va, 0, cr);
  if (err)
    return -1;
  return va.va_gid;
}", name);
#endif /* __solaris__ */
#ifdef __freebsd__
    if (!fist_search_bdt(name, auto_generated_functions)) {
      sprintf(fxnbuf, "gid_t
%s(vnode_t *vp, cred_t *cr)\n{
  vattr_t va;
  int err;

  VATTR_NULL(&va);
  err = VOP_GETATTR(vp, &va, cr, curproc);
  if (err)
    return -1;
  return va.va_gid;
}", name);
#endif /* __freebsd__ */
      if (!append_to_bdt(&auto_generated_functions, fxnbuf, name)) {
	sprintf(buf, "cannot store getattr function %s", name);
	return buf;
      }
      /* side effect: append "extern" definition to fist header file */
      sprintf(fxnbuf, "extern gid_t %s(vnode_t *vp, cred_t *cr);\n", name);
      if (!ecl_strcat(&auto_generated_externs, fxnbuf)) {
	sprintf(buf, "cannot store getattr extern definition %s", name);
	return buf;
      }
    }
#endif /* not __linux__ */
    return buf;
  }

  /* XXX: fix me */
  sprintf(buf, "unknown_dollar_var(%s,%s,%s,%s)", var,
	  (dv ? dv : "null"),
	  (dn ? dn : "null"),
	  (da ? da : "null"));
  return buf;
}