/*

 * pkcs15-cache.c: PKCS #15 file caching functions

 *

 * Copyright (C) 2001, 2002  Juha Yrjölä <juha.yrjola@iki.fi>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#include <sys/stat.h>

#include <limits.h>

#include <errno.h>

#include <assert.h>

#include "internal.h"

#include "pkcs15.h"

#include "common/compat_strlcpy.h"

#define RANDOM_UID_INDICATOR 0x08

static int generate_cache_filename(struct sc_pkcs15_card *p15card,

           const sc_path_t *path,

           char *buf, size_t bufsize)

{

  char dir[PATH_MAX];

  char *last_update = NULL;

  int  r;

  unsigned u;

  size_t change_counter;

  if (p15card->tokeninfo->serial_number == NULL

      && (p15card->card->uid.len == 0

        || p15card->card->uid.value[0] == RANDOM_UID_INDICATOR))

    return SC_ERROR_INVALID_ARGUMENTS;

  if (path->len > SC_MAX_PATH_SIZE)

    return SC_ERROR_INTERNAL;

  r = sc_get_cache_dir(p15card->card->ctx, dir, sizeof(dir));

  if (r)

    return r;

  snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir), "/");

  last_update = sc_pkcs15_get_lastupdate(p15card);

  if (!last_update)

    last_update = "NODATE";

  if (p15card->tokeninfo->serial_number) {

    snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir),

        "%s_%s", p15card->tokeninfo->serial_number,

        last_update);

  } else {

    snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir),

        "uid-%s_%s", sc_dump_hex(

          p15card->card->uid.value,

          p15card->card->uid.len), last_update);

  }

  if (SC_SUCCESS == sc_card_ctl(p15card->card, SC_CARDCTL_GET_CHANGE_COUNTER, &change_counter))

    snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir), "_%zu", change_counter);

  if (path->aid.len &&

    (path->type == SC_PATH_TYPE_FILE_ID || path->type == SC_PATH_TYPE_PATH))   {

    snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir), "_");

    for (u = 0; u < path->aid.len; u++)

      snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir),

          "%02X",  path->aid.value[u]);

  }

  else if (path->type != SC_PATH_TYPE_PATH)  {

    return SC_ERROR_INVALID_ARGUMENTS;

  }

  if (path->len)   {

    size_t offs = 0;

    if (path->len > 2 && memcmp(path->value, "\x3F\x00", 2) == 0)

      offs = 2;

    snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir), "_");

    for (u = 0; u < path->len - offs; u++)

      snprintf(dir + strlen(dir), sizeof(dir) - strlen(dir),

          "%02X",  path->value[u + offs]);

  }

  if (!buf)

    return SC_ERROR_BUFFER_TOO_SMALL;

  strlcpy(buf, dir, bufsize);

  return SC_SUCCESS;

}

int sc_pkcs15_read_cached_file(struct sc_pkcs15_card *p15card,

        const sc_path_t *path,

        u8 **buf, size_t *bufsize)

{

  char fname[PATH_MAX];

  int rv;

  FILE *f;

  size_t count;

  struct stat stbuf;

  u8 *data = NULL;

  if (path->len < 2)

    return SC_ERROR_INVALID_ARGUMENTS;

  /* Accept full path or FILE-ID path with AID */

  if ((path->type != SC_PATH_TYPE_PATH) && (path->type != SC_PATH_TYPE_FILE_ID || path->aid.len == 0))

    return SC_ERROR_INVALID_ARGUMENTS;

  sc_log(p15card->card->ctx, "try to read cache for %s", sc_print_path(path));

  rv = generate_cache_filename(p15card, path, fname, sizeof(fname));

  if (rv != SC_SUCCESS)

    return rv;

  sc_log(p15card->card->ctx, "read cached file %s", fname);

  f = fopen(fname, "rb");

  if (!f)

    return SC_ERROR_FILE_NOT_FOUND;

  if (fstat(fileno(f), &stbuf))   {

    fclose(f);

    return  SC_ERROR_FILE_NOT_FOUND;

  }

  if (path->count < 0) {

    count = stbuf.st_size;

  }

  else {

    count = path->count;

    if (path->index + count > (size_t)stbuf.st_size)   {

      rv = SC_ERROR_FILE_NOT_FOUND; /* cache file bad? */

      goto err;

    }

    if (0 != fseek(f, (long)path->index, SEEK_SET)) {

      rv = SC_ERROR_FILE_NOT_FOUND;

      goto err;

    }

  }

  if (*buf == NULL) {

    data = malloc((size_t)stbuf.st_size);

    if (data == NULL)   {

      rv = SC_ERROR_OUT_OF_MEMORY;

      goto err;

    }

  }

  else {

    if (count > *bufsize) {

      rv =  SC_ERROR_BUFFER_TOO_SMALL;

      goto err;

    }

    data = *buf;

  }

  if (count != fread(data, 1, count, f)) {

    rv = SC_ERROR_BUFFER_TOO_SMALL;

    goto err;

  }

  *buf = data;

  *bufsize = count;

  rv = SC_SUCCESS;

err:

  if (rv != SC_SUCCESS) {

    if (data != *buf) {

      free(data);

    }

  }

  fclose(f);

  return rv;

}

int sc_pkcs15_cache_file(struct sc_pkcs15_card *p15card,

       const sc_path_t *path,

       const u8 *buf, size_t bufsize)

{

  char fname[PATH_MAX];

  int r;

  long len;

  FILE *f;

  size_t c;

  r = generate_cache_filename(p15card, path, fname, sizeof(fname));

  if (r != 0)

    return r;

  f = fopen(fname, "ab");

  /* If the open failed because the cache directory does

   * not exist, create it and a re-try the fopen() call.

   */

  if (f == NULL && errno == ENOENT) {

    if ((r = sc_make_cache_dir(p15card->card->ctx)) < 0)

      return r;

    f = fopen(fname, "ab");

  }

  if (f == NULL)

    return 0;

  /* we opened the file for appending so we should be at the end of file.

   * The ftell() will give use the length of the file */

  len = ftell(f);

  if (len > path->index) {

    /* override previous cache records on this location */

    r = fseek(f, path->index, SEEK_SET);

    if (r != 0) {

      fclose(f);

      return 0;

    }

  } else if (path->index > len) {

    /* We miss some bytes so we will not cache this chunk */

    fclose(f);

    return 0;

  }

  c = fwrite(buf, 1, bufsize, f);

  fclose(f);

  if (c != bufsize) {

    sc_log(p15card->card->ctx, "fwrite() wrote only %zu bytes", c);

    unlink(fname);

    return SC_ERROR_INTERNAL;

  }

  return 0;

}