* Copyright (c) 2017 The NetBSD Foundation, Inc.

/* $NetBSD: defined.c,v 1.2 2019/11/16 12:26:54 tkusumi Exp $ */

/*-
* Copyright (c) 2017 The NetBSD Foundation, Inc.
* Copyright (c) 2016 The DragonFly Project
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Tomohiro Kusumi <[email protected]>.
*
* This software was developed by Edward Tomasz Napierala under sponsorship
* from the FreeBSD Foundation.
*
* 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 THE 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.
*
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: defined.c,v 1.2 2019/11/16 12:26:54 tkusumi Exp $");

/*
* All the "defined" stuff is for handling variables,
* such as ${OSNAME}, in maps.
*/

#include <sys/types.h>
#include <sys/utsname.h>
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"

static TAILQ_HEAD(, defined_value) defined_values;

static const char *
defined_find(const char *name)
{
struct defined_value *d;

TAILQ_FOREACH(d, &defined_values, d_next) {
if (strcmp(d->d_name, name) == 0)
return d->d_value;
}

return NULL;
}

char *
defined_expand(const char *string)
{
const char *value;
char c, *expanded, *name;
int ret;
size_t i, before_len = 0, name_off = 0, name_len = 0, after_off = 0;
bool backslashed = false, bracketed = false;

expanded = checked_strdup(string);

for (i = 0; string[i] != '\0'; i++) {
c = string[i];
if (c == '\\' && backslashed == false) {
backslashed = true;
continue;
}
if (backslashed) {
backslashed = false;
continue;
}
backslashed = false;
if (c != '$')
continue;

/*
* The 'before_len' variable contains the number
* of characters before the '$'.
*/
before_len = i;
assert(i + 1 < strlen(string));
if (string[i + 1] == '{')
bracketed = true;

if (string[i + 1] == '\0') {
log_warnx("truncated variable");
return NULL;
}

/*
* Skip '$'.
*/
i++;

if (bracketed) {
if (string[i + 1] == '\0') {
log_warnx("truncated variable");
return NULL;
}

/*
* Skip '{'.
*/
i++;
}

/*
* The 'name_off' variable contains the number
* of characters before the variable name,
* including the "$" or "${".
*/
name_off = i;

for (; string[i] != '\0'; i++) {
c = string[i];
/*
* XXX: Decide on the set of characters that can be
* used in a variable name.
*/
if (isalnum((unsigned char)c) || c == '_')
continue;

/*
* End of variable name.
*/
if (bracketed) {
if (c != '}')
continue;

/*
* The 'after_off' variable contains the number
* of characters before the rest of the string,
* i.e. after the variable name.
*/
after_off = i + 1;
assert(i > 1);
assert(i - 1 > name_off);
name_len = i - name_off;
break;
}

after_off = i;
assert(i > 1);
assert(i > name_off);
name_len = i - name_off;
break;
}

name = strndup(string + name_off, name_len);
if (name == NULL)
log_err(1, "strndup");
value = defined_find(name);
if (value == NULL) {
log_warnx("undefined variable ${%s}", name);
return NULL;
}

/*
* Concatenate it back.
*/
ret = asprintf(&expanded, "%.*s%s%s",
(int)before_len, string, value, string + after_off);
if (ret < 0)
log_err(1, "asprintf");

//log_debugx("\"%s\" expanded to \"%s\"", string, expanded);
free(name);

/*
* Figure out where to start searching for next variable.
*/
string = expanded;
i = before_len + strlen(value);
backslashed = bracketed = false;
before_len = name_off = name_len = after_off = 0;
assert(i <= strlen(string));
}

if (before_len != 0 || name_off != 0 || name_len != 0
|| after_off != 0) {
log_warnx("truncated variable");
return NULL;
}

return expanded;
}

static void
defined_add(const char *name, const char *value)
{
struct defined_value *d;
const char *found;

found = defined_find(name);
if (found != NULL)
log_errx(1, "variable %s already defined", name);

log_debugx("defining variable %s=%s", name, value);

d = calloc(1, sizeof(*d));
if (d == NULL)
log_err(1, "calloc");
d->d_name = checked_strdup(name);
d->d_value = checked_strdup(value);

TAILQ_INSERT_TAIL(&defined_values, d, d_next);
}

void
defined_parse_and_add(char *def)
{
char *name, *value;

value = def;
name = strsep(&value, "=");

if (value == NULL || value[0] == '\0')
log_errx(1, "missing variable value");
if (name == NULL || name[0] == '\0')
log_errx(1, "missing variable name");

defined_add(name, value);
}

void
defined_init(void)
{
struct utsname name;
int error;

TAILQ_INIT(&defined_values);

error = uname(&name);
if (error != 0)
log_err(1, "uname");

defined_add("ARCH", name.machine);
defined_add("CPU", name.machine);
defined_add("DOLLAR", "$");
defined_add("HOST", name.nodename);
defined_add("OSNAME", name.sysname);
defined_add("OSREL", name.release);
defined_add("OSVERS", name.version);
}