/* assuan.c - Global interface (not specific to context).
 * Copyright (C) 2009 Free Software Foundation, Inc.
 * Copyright (C) 2001, 2002, 2012, 2013 g10 Code GmbH
 *
 * This file is part of Assuan.
 *
 * Assuan 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.
 *
 * Assuan 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 program; if not, see <http://www.gnu.org/licenses/>.
 * SPDX-License-Identifier: LGPL-2.1+
 */


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

#include <stdlib.h>

#include "assuan-defs.h"
#include "debug.h"


#define digitp(a) ((a) >= '0' && (a) <= '9')



/* Global default state.  */

/* Functions called before and after blocking syscalls.  */
static void (*pre_syscall_func) (void);
static void (*post_syscall_func) (void);

/* Variable to see if functions above are initialized.  */
static int _assuan_syscall_func_initialized;


/* The default error source gor generated error codes.  */
static gpg_err_source_t _assuan_default_err_source = GPG_ERR_SOURCE_USER_1;

/* The default memory management functions.  */
static struct assuan_malloc_hooks _assuan_default_malloc_hooks =
  { malloc, realloc, free };

/* The default logging handler.  */
static assuan_log_cb_t _assuan_default_log_cb = _assuan_log_handler;
static void *_assuan_default_log_cb_data = NULL;


/* Set the default gpg error source.  */
void
assuan_set_gpg_err_source (gpg_err_source_t errsource)
{
  _assuan_default_err_source = errsource;
}


/* Get the default gpg error source.  */
gpg_err_source_t
assuan_get_gpg_err_source (void)
{
  return _assuan_default_err_source;
}


/* Set the default malloc hooks.  */
void
assuan_set_malloc_hooks (assuan_malloc_hooks_t malloc_hooks)
{
  _assuan_default_malloc_hooks = *malloc_hooks;
}


/* Get the default malloc hooks.  */
assuan_malloc_hooks_t
assuan_get_malloc_hooks (void)
{
  return &_assuan_default_malloc_hooks;
}


/* Set the default log callback handler.  */
void
assuan_set_log_cb (assuan_log_cb_t log_cb, void *log_cb_data)
{
  _assuan_default_log_cb = log_cb;
  _assuan_default_log_cb_data = log_cb_data;
  _assuan_init_log_envvars ();
}


/* Get the default log callback handler.  */
void
assuan_get_log_cb (assuan_log_cb_t *log_cb, void **log_cb_data)
{
  *log_cb = _assuan_default_log_cb;
  *log_cb_data = _assuan_default_log_cb_data;
}


void
assuan_set_system_hooks (assuan_system_hooks_t system_hooks)
{
  _assuan_system_hooks_copy (&_assuan_system_hooks, system_hooks);
}


/* Used before blocking system calls.  */
void
_assuan_pre_syscall (void)
{
  if (pre_syscall_func)
    pre_syscall_func ();
}


/* Used after blocking system calls.  */
void
_assuan_post_syscall (void)
{
  if (post_syscall_func)
    post_syscall_func ();
}

/* Create a new Assuan context.  The initial parameters are all needed
   in the creation of the context.  */
gpg_error_t
assuan_new_ext (assuan_context_t *r_ctx, gpg_err_source_t err_source,
		assuan_malloc_hooks_t malloc_hooks, assuan_log_cb_t log_cb,
		void *log_cb_data)
{
  struct assuan_context_s wctx;
  assuan_context_t ctx;

  if (!_assuan_syscall_func_initialized)
    {
      gpgrt_get_syscall_clamp (&pre_syscall_func, &post_syscall_func);
      _assuan_syscall_func_initialized = 1;
    }

  /* Set up a working context so we can use standard functions.  */
  memset (&wctx, 0, sizeof (wctx));
  wctx.err_source = err_source;
  wctx.malloc_hooks = *malloc_hooks;
  wctx.log_cb = log_cb;
  wctx.log_cb_data = log_cb_data;

  /* Need a new block for the trace macros to work.  */
  {
    TRACE_BEG8 (&wctx, ASSUAN_LOG_CTX, "assuan_new_ext", r_ctx,
		"err_source = %i (%s), malloc_hooks = %p (%p, %p, %p), "
		"log_cb = %p, log_cb_data = %p", err_source,
		gpg_strsource (err_source), malloc_hooks, malloc_hooks->malloc,
		malloc_hooks->realloc, malloc_hooks->free, log_cb, log_cb_data);

    *r_ctx = NULL;
    ctx = _assuan_malloc (&wctx, sizeof (*ctx));
    if (!ctx)
      return TRACE_ERR (gpg_err_code_from_syserror ());

    memcpy (ctx, &wctx, sizeof (*ctx));
    ctx->system = _assuan_system_hooks;

    /* FIXME: Delegate to subsystems/engines, as the FDs are not our
       responsibility (we don't deallocate them, for example).  */
    ctx->input_fd = ASSUAN_INVALID_FD;
    ctx->output_fd = ASSUAN_INVALID_FD;
    ctx->inbound.fd = ASSUAN_INVALID_FD;
    ctx->outbound.fd = ASSUAN_INVALID_FD;
    ctx->listen_fd = ASSUAN_INVALID_FD;

    *r_ctx = ctx;

    return TRACE_SUC1 ("ctx=%p", ctx);
  }
}


/* Create a new context with default arguments.  */
gpg_error_t
assuan_new (assuan_context_t *r_ctx)
{
  return assuan_new_ext (r_ctx, _assuan_default_err_source,
			 &_assuan_default_malloc_hooks,
			 _assuan_default_log_cb,
			 _assuan_default_log_cb_data);
}


/* Release all resources associated with an engine operation.  */
void
_assuan_reset (assuan_context_t ctx)
{
  if (ctx->engine.release)
    {
      (*ctx->engine.release) (ctx);
      ctx->engine.release = NULL;
    }

  /* FIXME: Clean standard commands */
}


/* Release all resources associated with the given context.  */
void
assuan_release (assuan_context_t ctx)
{
  if (! ctx)
    return;

  TRACE (ctx, ASSUAN_LOG_CTX, "assuan_release", ctx);

  _assuan_reset (ctx);
  /* None of the members that are our responsibility requires
     deallocation.  To avoid sensitive data in the line buffers we
     wipe them out, though.  Note that we can't wipe the entire
     context because it also has a pointer to the actual free().  */
  wipememory (&ctx->inbound, sizeof ctx->inbound);
  wipememory (&ctx->outbound, sizeof ctx->outbound);
  _assuan_free (ctx, ctx);
}



/*
    Version number stuff.
 */

static const char*
parse_version_number (const char *s, int *number)
{
  int val = 0;

  if (*s == '0' && digitp (s[1]))
    return NULL;  /* Leading zeros are not allowed.  */
  for (; digitp (*s); s++)
    {
      val *= 10;
      val += *s - '0';
    }
  *number = val;
  return val < 0 ? NULL : s;
}


static const char *
parse_version_string (const char *s, int *major, int *minor, int *micro)
{
  s = parse_version_number (s, major);
  if (!s || *s != '.')
    return NULL;
  s++;
  s = parse_version_number (s, minor);
  if (!s || *s != '.')
    return NULL;
  s++;
  s = parse_version_number (s, micro);
  if (!s)
    return NULL;
  return s;  /* Patchlevel.  */
}


static const char *
compare_versions (const char *my_version, const char *req_version)
{
  int my_major, my_minor, my_micro;
  int rq_major, rq_minor, rq_micro;
  const char *my_plvl, *rq_plvl;

  if (!req_version)
    return my_version;
  if (!my_version)
    return NULL;

  my_plvl = parse_version_string (my_version, &my_major, &my_minor, &my_micro);
  if (!my_plvl)
    return NULL;	/* Very strange: our own version is bogus.  */
  rq_plvl = parse_version_string(req_version,
				 &rq_major, &rq_minor, &rq_micro);
  if (!rq_plvl)
    return NULL;	/* Requested version string is invalid.  */

  if (my_major > rq_major
	|| (my_major == rq_major && my_minor > rq_minor)
      || (my_major == rq_major && my_minor == rq_minor
	  && my_micro > rq_micro)
      || (my_major == rq_major && my_minor == rq_minor
	  && my_micro == rq_micro))
    {
      return my_version;
    }
  return NULL;
}


/*
 * Check that the the version of the library is at minimum REQ_VERSION
 * and return the actual version string; return NULL if the condition
 * is not met.  If NULL is passed to this function, no check is done
 * and the version string is simply returned.
 */
const char *
assuan_check_version (const char *req_version)
{
  if (req_version && req_version[0] == 1 && req_version[1] == 1)
    return _assuan_sysutils_blurb ();
  return compare_versions (PACKAGE_VERSION, req_version);
}