text: /*-
   * Copyright (c) 2010-2011 Varnish Software AS
   * All rights reserved.
   *
   * Author: Sanjoy Das <sanjoy@playingwithpointers.com>
   *
   * SPDX-License-Identifier: BSD-2-Clause
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * XXX: It might make sense to use just a single global list of all files
   * XXX: and use the call-private pointer to point to the file instance on
   * XXX: that list.
   * XXX: Duplicates in the global list can be avoided by examining the
   * XXX: dev+inode fields of the stat structure.
   * XXX: Individual files would need to be refcounted, so they can be
   * XXX: deleted when no VCL's reference them.
   *
   * XXX: We should periodically stat(2) the filename and check if the
   * XXX: underlying file has been updated.
   */
  
  #include "config.h"
  
  #include <stdlib.h>
  #include <string.h>
  
  #include "cache/cache.h"
  
  #include "vfil.h"
  
  #include "vcc_if.h"
  
  struct frfile {
  	unsigned			magic;
  #define CACHED_FILE_MAGIC 0xa8e9d87a
  	char				*file_name;
  	char				*contents;
  	int				refcount;
  	VTAILQ_ENTRY(frfile)		list;
  };
  
  static VTAILQ_HEAD(, frfile)	frlist = VTAILQ_HEAD_INITIALIZER(frlist);
  static pthread_mutex_t		frmtx = PTHREAD_MUTEX_INITIALIZER;
  
  static void
  free_frfile(void *ptr)
  {
  	struct frfile *frf;
  
  	CAST_OBJ_NOTNULL(frf, ptr, CACHED_FILE_MAGIC);
  
  	AZ(pthread_mutex_lock(&frmtx));
  	if (--frf->refcount > 0)
  		frf = NULL;
  	else
  		VTAILQ_REMOVE(&frlist, frf, list);
  	AZ(pthread_mutex_unlock(&frmtx));
  	if (frf != NULL) {
  		free(frf->contents);
  		free(frf->file_name);
  		FREE_OBJ(frf);
  	}
  }
  
  VCL_STRING v_matchproto_(td_std_fileread)
  vmod_fileread(VRT_CTX, struct vmod_priv *priv,
      VCL_STRING file_name)
  {
  	struct frfile *frf = NULL;
  	char *s;
  
  	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
  	AN(priv);
  
  	if (file_name == NULL)
  		return (NULL);
  
  	if (priv->priv != NULL) {
  		CAST_OBJ_NOTNULL(frf, priv->priv, CACHED_FILE_MAGIC);
  		if (!strcmp(file_name, frf->file_name))
  			return (frf->contents);
  	}
  
  	AZ(pthread_mutex_lock(&frmtx));
  	if (frf != NULL)
  		frf->refcount--;
  	VTAILQ_FOREACH(frf, &frlist, list) {
  		if (!strcmp(file_name, frf->file_name)) {
  			frf->refcount++;
  			break;
  		}
  	}
  	AZ(pthread_mutex_unlock(&frmtx));
  	if (frf != NULL) {
  		priv->free = free_frfile;
  		priv->priv = frf;
  		return (frf->contents);
  	}
  
  	s = VFIL_readfile(NULL, file_name, NULL);
  	if (s != NULL) {
  		ALLOC_OBJ(frf, CACHED_FILE_MAGIC);
  		AN(frf);
  		frf->file_name = strdup(file_name);
  		AN(frf->file_name);
  		frf->refcount = 1;
  		frf->contents = s;
  		priv->free = free_frfile;
  		priv->priv = frf;
  		AZ(pthread_mutex_lock(&frmtx));
  		VTAILQ_INSERT_HEAD(&frlist, frf, list);
  		AZ(pthread_mutex_unlock(&frmtx));
  	}
  	return (s);
  }
  