arena.c

来自「支持SSL v2/v3, TLS, PKCS #5, PKCS #7, PKCS」· C语言 代码 · 共 1,122 行 · 第 1/2 页

/* 
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is the Netscape security libraries.
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are 
 * Copyright (C) 1994-2000 Netscape Communications Corporation.  All
 * Rights Reserved.
 * 
 * Contributor(s):
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL"), in which case the provisions of the GPL are applicable 
 * instead of those above.  If you wish to allow use of your 
 * version of this file only under the terms of the GPL and not to
 * allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by
 * the GPL.  If you do not delete the provisions above, a recipient
 * may use your version of this file under either the MPL or the
 * GPL.
 */

#ifdef DEBUG
static const char CVS_ID[] = "@(#) $RCSfile: arena.c,v $ $Revision: 1.2 $ $Date: 2000/04/19 21:23:13 $ $Name: NSS_3_1_1_RTM $";
#endif /* DEBUG */

/*
 * arena.c
 *
 * This contains the implementation of NSS's thread-safe arenas.
 */

#ifndef BASE_H
#include "base.h"
#endif /* BASE_H */

#ifdef ARENA_THREADMARK
#include "prthread.h"
#endif /* ARENA_THREADMARK */

#include "prlock.h"
#include "plarena.h"

/*
 * NSSArena
 *
 * This is based on NSPR's arena code, but it is threadsafe.
 *
 * The public methods relating to this type are:
 *
 *  NSSArena_Create  -- constructor
 *  NSSArena_Destroy
 *
 * The nonpublic methods relating to this type are:
 *
 *  nssArena_Create  -- constructor
 *  nssArena_Destroy
 *  nssArena_Mark
 *  nssArena_Release
 *  nssArena_Unmark
 * 
 *  nss_ZAlloc
 *  nss_ZFreeIf
 *  nss_ZRealloc
 *
 * In debug builds, the following calls are available:
 *
 *  nssArena_verifyPointer
 *  nssArena_registerDestructor
 *  nssArena_deregisterDestructor
 */

struct NSSArenaStr {
  PLArenaPool pool;
  PRLock *lock;
#ifdef ARENA_THREADMARK
  PRThread *marking_thread;
  nssArenaMark *first_mark;
  nssArenaMark *last_mark;
#endif /* ARENA_THREADMARK */
#ifdef ARENA_DESTRUCTOR_LIST
  struct arena_destructor_node *first_destructor;
  struct arena_destructor_node *last_destructor;
#endif /* ARENA_DESTRUCTOR_LIST */
};

/*
 * nssArenaMark
 *
 * This type is used to mark the current state of an NSSArena.
 */

struct nssArenaMarkStr {
  PRUint32 magic;
  void *mark;
#ifdef ARENA_THREADMARK
  nssArenaMark *next;
#endif /* ARENA_THREADMARK */
#ifdef ARENA_DESTRUCTOR_LIST
  struct arena_destructor_node *next_destructor;
  struct arena_destructor_node *prev_destructor;
#endif /* ARENA_DESTRUCTOR_LIST */
};

#define MARK_MAGIC 0x4d41524b /* "MARK" how original */

/*
 * But first, the pointer-tracking code
 */
#ifdef DEBUG
extern const NSSError NSS_ERROR_INTERNAL_ERROR;

static nssPointerTracker arena_pointer_tracker;

static PRStatus
arena_add_pointer
(
  const NSSArena *arena
)
{
  PRStatus rv;

  rv = nssPointerTracker_initialize(&arena_pointer_tracker);
  if( PR_SUCCESS != rv ) {
    return rv;
  }

  rv = nssPointerTracker_add(&arena_pointer_tracker, arena);
  if( PR_SUCCESS != rv ) {
    NSSError e = NSS_GetError();
    if( NSS_ERROR_NO_MEMORY != e ) {
      nss_SetError(NSS_ERROR_INTERNAL_ERROR);
    }

    return rv;
  }

  return PR_SUCCESS;
}

static PRStatus
arena_remove_pointer
(
  const NSSArena *arena
)
{
  PRStatus rv;

  rv = nssPointerTracker_remove(&arena_pointer_tracker, arena);
  if( PR_SUCCESS != rv ) {
    nss_SetError(NSS_ERROR_INTERNAL_ERROR);
  }

  return rv;
}

/*
 * nssArena_verifyPointer
 *
 * This method is only present in debug builds.
 *
 * If the specified pointer is a valid pointer to an NSSArena object,
 * this routine will return PR_SUCCESS.  Otherwise, it will put an
 * error on the error stack and return PR_FAILURE.
 *
 * The error may be one of the following values:
 *  NSS_ERROR_INVALID_ARENA
 *
 * Return value:
 *  PR_SUCCESS if the pointer is valid
 *  PR_FAILURE if it isn't
 */

NSS_IMPLEMENT PRStatus
nssArena_verifyPointer
(
  const NSSArena *arena
)
{
  PRStatus rv;

  rv = nssPointerTracker_initialize(&arena_pointer_tracker);
  if( PR_SUCCESS != rv ) {
    /*
     * This is a little disingenious.  We have to initialize the
     * tracker, because someone could "legitimately" try to verify
     * an arena pointer before one is ever created.  And this step
     * might fail, due to lack of memory.  But the only way that
     * this step can fail is if it's doing the call_once stuff,
     * (later calls just no-op).  And if it didn't no-op, there
     * aren't any valid arenas.. so the argument certainly isn't one.
     */
    nss_SetError(NSS_ERROR_INVALID_ARENA);
    return PR_FAILURE;
  }

  rv = nssPointerTracker_verify(&arena_pointer_tracker, arena);
  if( PR_SUCCESS != rv ) {
    nss_SetError(NSS_ERROR_INVALID_ARENA);
    return PR_FAILURE;
  }

  return PR_SUCCESS;
}
#endif /* DEBUG */

#ifdef ARENA_DESTRUCTOR_LIST

struct arena_destructor_node {
  struct arena_destructor_node *next;
  struct arena_destructor_node *prev;
  void (*destructor)(void *argument);
  void *arg;
};

/*
 * nssArena_registerDestructor
 *
 * This routine stores a pointer to a callback and an arbitrary
 * pointer-sized argument in the arena, at the current point in
 * the mark stack.  If the arena is destroyed, or an "earlier"
 * mark is released, then this destructor will be called at that
 * time.  Note that the destructor will be called with the arena
 * locked, which means the destructor may free memory in that
 * arena, but it may not allocate or cause to be allocated any
 * memory.  This callback facility was included to support our
 * debug-version pointer-tracker feature; overuse runs counter to
 * the the original intent of arenas.  This routine returns a 
 * PRStatus value; if successful, it will return PR_SUCCESS.  If 
 * unsuccessful, it will set an error on the error stack and 
 * return PR_FAILURE.
 *
 * The error may be one of the following values:
 *  NSS_ERROR_INVALID_ARENA
 *  NSS_ERROR_NO_MEMORY
 *
 * Return value:
 *  PR_SUCCESS
 *  PR_FAILURE
 */

NSS_IMPLEMENT PRStatus
nssArena_registerDestructor
(
  NSSArena *arena,
  void (*destructor)(void *argument),
  void *arg
)
{
  struct arena_destructor_node *it;

#ifdef NSSDEBUG
  if( PR_SUCCESS != nssArena_verifyPointer(arena) ) {
    return PR_FAILURE;
  }
#endif /* NSSDEBUG */
  
  it = nss_ZNEW(arena, struct arena_destructor_node);
  if( (struct arena_destructor_node *)NULL == it ) {
    return PR_FAILURE;
  }

  it->prev = arena->last_destructor;
  arena->last_destructor->next = it;
  arena->last_destructor = it;
  it->destructor = destructor;
  it->arg = arg;

  if( (nssArenaMark *)NULL != arena->last_mark ) {
    arena->last_mark->prev_destructor = it->prev;
    arena->last_mark->next_destructor = it->next;
  }

  return PR_SUCCESS;
}

NSS_IMPLEMENT PRStatus
nssArena_deregisterDestructor
(
  NSSArena *arena,
  void (*destructor)(void *argument),
  void *arg
)
{
  struct arena_destructor_node *it;

#ifdef NSSDEBUG
  if( PR_SUCCESS != nssArena_verifyPointer(arena) ) {
    return PR_FAILURE;
  }
#endif /* NSSDEBUG */

  for( it = arena->first_destructor; it; it = it->next ) {
    if( (it->destructor == destructor) && (it->arg == arg) ) {
      break;
    }
  }

  if( (struct arena_destructor_node *)NULL == it ) {
    nss_SetError(NSS_ERROR_NOT_FOUND);
    return PR_FAILURE;
  }

  if( it == arena->first_destructor ) {
    arena->first_destructor = it->next;
  }

  if( it == arena->last_destructor ) {
    arena->last_destructor = it->prev;
  }

  if( (struct arena_destructor_node *)NULL != it->prev ) {
    it->prev->next = it->next;
  }

  if( (struct arena_destructor_node *)NULL != it->next ) {
    it->next->prev = it->prev;
  }

  {
    nssArenaMark *m;
    for( m = arena->first_mark; m; m = m->next ) {
      if( m->next_destructor == it ) {
        m->next_destructor = it->next;
      }
      if( m->prev_destructor == it ) {
        m->prev_destructor = it->prev;
      }
    }
  }

  nss_ZFreeIf(it);
  return PR_SUCCESS;
}

static void
nss_arena_call_destructor_chain
(
  struct arena_destructor_node *it
)
{
  for( ; it ; it = it->next ) {
    (*(it->destructor))(it->arg);
  }
}

#endif /* ARENA_DESTRUCTOR_LIST */

/*
 * NSSArena_Create
 *
 * This routine creates a new memory arena.  This routine may return
 * NULL upon error, in which case it will have created an error stack.
 *
 * The top-level error may be one of the following values:
 *  NSS_ERROR_NO_MEMORY
 *
 * Return value:
 *  NULL upon error
 *  A pointer to an NSSArena upon success
 */

NSS_IMPLEMENT NSSArena *
NSSArena_Create
(
  void
)
{
  nss_ClearErrorStack();
  return nssArena_Create();
}

/*
 * nssArena_Create
 *
 * This routine creates a new memory arena.  This routine may return
 * NULL upon error, in which case it will have set an error on the 
 * error stack.
 *
 * The error may be one of the following values:
 *  NSS_ERROR_NO_MEMORY
 *
 * Return value:
 *  NULL upon error
 *  A pointer to an NSSArena upon success
 */

NSS_IMPLEMENT NSSArena *
nssArena_Create
(
  void
)
{
  NSSArena *rv = (NSSArena *)NULL;

  rv = nss_ZNEW((NSSArena *)NULL, NSSArena);
  if( (NSSArena *)NULL == rv ) {
    nss_SetError(NSS_ERROR_NO_MEMORY);
    return (NSSArena *)NULL;
  }

  rv->lock = PR_NewLock();
  if( (PRLock *)NULL == rv->lock ) {
    (void)nss_ZFreeIf(rv);
    nss_SetError(NSS_ERROR_NO_MEMORY);
    return (NSSArena *)NULL;
  }

  /*
   * Arena sizes.  The current security code has 229 occurrences of
   * PORT_NewArena.  The default chunksizes specified break down as
   *
   *  Size    Mult.   Specified as
   *   512       1    512
   *  1024       7    1024
   *  2048       5    2048
   *  2048       5    CRMF_DEFAULT_ARENA_SIZE
   *  2048     190    DER_DEFAULT_CHUNKSIZE
   *  2048      20    SEC_ASN1_DEFAULT_ARENA_SIZE
   *  4096       1    4096
   *
   * Obviously this "default chunksize" flexibility isn't very 
   * useful to us, so I'll just pick 2048.
   */

  PL_InitArenaPool(&rv->pool, "NSS", 2048, sizeof(double));

#ifdef DEBUG
  {
    PRStatus st;
    st = arena_add_pointer(rv);
    if( PR_SUCCESS != st ) {
      PL_FinishArenaPool(&rv->pool);
      PR_DestroyLock(rv->lock);
      (void)nss_ZFreeIf(rv);
      return (NSSArena *)NULL;
    }
  }
#endif /* DEBUG */

  return rv;
}

/*
 * NSSArena_Destroy
 *
 * This routine will destroy the specified arena, freeing all memory
 * allocated from it.  This routine returns a PRStatus value; if 
 * successful, it will return PR_SUCCESS.  If unsuccessful, it will
 * create an error stack and return PR_FAILURE.
 *
 * The top-level error may be one of the following values:
 *  NSS_ERROR_INVALID_ARENA
 *
 * Return value:
 *  PR_SUCCESS upon success
 *  PR_FAILURE upon failure
 */

NSS_IMPLEMENT PRStatus
NSSArena_Destroy
(
  NSSArena *arena
)
{
  nss_ClearErrorStack();

#ifdef DEBUG
  if( PR_SUCCESS != nssArena_verifyPointer(arena) ) {
    return PR_FAILURE;
  }
#endif /* DEBUG */

  return nssArena_Destroy(arena);
}

/*
 * nssArena_Destroy
 *
 * This routine will destroy the specified arena, freeing all memory
 * allocated from it.  This routine returns a PRStatus value; if 
 * successful, it will return PR_SUCCESS.  If unsuccessful, it will
 * set an error on the error stack and return PR_FAILURE.
 *
 * The error may be one of the following values:
 *  NSS_ERROR_INVALID_ARENA
 *
 * Return value:
 *  PR_SUCCESS
 *  PR_FAILURE
 */

NSS_IMPLEMENT PRStatus
nssArena_Destroy
(
  NSSArena *arena
)
{
  PRLock *lock;

#ifdef NSSDEBUG
  if( PR_SUCCESS != nssArena_verifyPointer(arena) ) {
    return PR_FAILURE;
  }
#endif /* NSSDEBUG */

  PR_Lock(arena->lock);
  if( (PRLock *)NULL == arena->lock ) {
    /* Just got destroyed */
    nss_SetError(NSS_ERROR_INVALID_ARENA);
    return PR_FAILURE;
  }
  
#ifdef DEBUG
  if( PR_SUCCESS != arena_remove_pointer(arena) ) {
    return PR_FAILURE;
  }
#endif /* DEBUG */

#ifdef ARENA_DESTRUCTOR_LIST
  /* Note that the arena is locked at this time */
  nss_arena_call_destructor_chain(arena->first_destructor);
#endif /* ARENA_DESTRUCTOR_LIST */

  PL_FinishArenaPool(&arena->pool);
  lock = arena->lock;
  arena->lock = (PRLock *)NULL;
  PR_Unlock(lock);
  PR_DestroyLock(lock);
  (void)nss_ZFreeIf(arena);
  return PR_SUCCESS;
}

/*
 * nssArena_Mark
 *
 * This routine "marks" the current state of an arena.  Space
 * allocated after the arena has been marked can be freed by
 * releasing the arena back to the mark with nssArena_Release,
 * or committed by calling nssArena_Unmark.  When successful, 
 * this routine returns a valid nssArenaMark pointer.  This 
 * routine may return NULL upon error, in which case it will 
 * have set an error on the error stack.
 *
 * The error may be one of the following values:
 *  NSS_ERROR_INVALID_ARENA
 *  NSS_ERROR_NO_MEMORY
 *  NSS_ERROR_ARENA_MARKED_BY_ANOTHER_THREAD
 *
 * Return value: