source: vendor/current/lib/util/tini.c

/*
 * Trivial smb.conf parsing code
 *
 * Copyright Volker Lendecke <vl@samba.org> 2014
 *
 * 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, and the entire permission notice in its entirety,
 *    including the disclaimer of warranties.
 * 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.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * ALTERNATIVELY, this product may be distributed under the terms of
 * the GNU Public License Version 3 or later, in which case the
 * provisions of the GPL are required INSTEAD OF the above restrictions.
 * (This clause is necessary due to a potential bad interaction between the
 * GPL and the restrictions contained in a BSD-style copyright.)
 *
 * THIS SOFTWARE IS PROVIDED `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 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 <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include "tini.h"

static bool c_isspace(char c)
{
        unsigned char uc = c;
        if (c != uc) {
                return false;
        }
        return isspace(uc);
}

static int next_content(FILE *f)
{
        int c;

        for (c = fgetc(f); c != EOF; c = fgetc(f)) {
                if (!c_isspace(c)) {
                        break;
                }
                if (c == '\n') {
                        break;
                }
        }

        return c;
}

static int next_end_of_line(FILE *f)
{
        int c;

        for (c = fgetc(f); c != EOF; c = fgetc(f)) {
                if (c == '\n') {
                        break;
                }
        }
        return c;
}

static bool make_space(char **buf, size_t *buflen, size_t position)
{
        char *tmp;

        if (position < *buflen) {
                return true;
        }
        tmp = realloc(*buf, (*buflen) * 2);
        if (tmp == NULL) {
                return false;
        }
        *buf = tmp;
        *buflen *= 2;
        return true;
}

/*
 * Get a conf line into *pbuf (which must be a malloc'ed buffer already).
 *
 * Ignores leading spaces
 * Ignores comment lines
 * Ignores empty lines
 * Takes care of continuation lines
 * Zaps multiple spaces into one
 */

static int get_line(FILE *f, char **pbuf, size_t *pbuflen)
{
        int c;
        char *buf;
        size_t buflen, pos;

        buf = *pbuf;
        buflen = *pbuflen;
        pos = 0;

next_line:

        c = next_content(f);
        if (c == EOF) {
                return ENOENT;
        }

        if ((c == '#') || (c == ';')) {
                /*
                 * Line starting with a comment, skip
                 */
                c = next_end_of_line(f);
                if (c == EOF) {
                        return ENOENT;
                }
                goto next_line;
        }

        if (c == '\n') {
                /*
                 * Blank line, skip
                 */
                goto next_line;
        }

        for ( ; c != EOF ; c = fgetc(f)) {

                if (c == '\n') {

                        if ((pos > 0) && (buf[pos-1] == '\\')) {
                                /*
                                 * Line ends in "\". Continuation.
                                 */
                                pos -= 1;
                                continue;
                        }

                        if ((pos > 1) && (buf[pos-2] == '\\') &&
                            c_isspace(buf[pos-1])) {
                                /*
                                 * Line ends in "\ ". Mind that we zap
                                 * multiple spaces into one. Continuation.
                                 */
                                pos -= 2;
                                continue;
                        }

                        /*
                         * No continuation, done with the line
                         */
                        break;
                }

                if ((pos > 0) && c_isspace(buf[pos-1]) && c_isspace(c)) {
                        /*
                         * Zap multiple spaces to one
                         */
                        continue;
                }

                if (!make_space(&buf, &buflen, pos)) {
                        return ENOMEM;
                }
                buf[pos++] = c;
        }

        if (!make_space(&buf, &buflen, pos)) {
                return ENOMEM;
        }
        buf[pos++] = '\0';

        *pbuf = buf;
        return 0;
}

static bool parse_section(
        char *buf, bool (*sfunc)(const char *section, void *private_data),
        void *private_data)
{
        char *p, *q;

        p = buf+1;              /* skip [ */

        q = strchr(p, ']');
        if (q == NULL) {
                return false;
        }
        *q = '\0';

        return sfunc(p, private_data);
}

static char *trim_one_space(char *buf)
{
        size_t len;

        if (c_isspace(buf[0])) {
                buf += 1;
        }
        len = strlen(buf);
        if (len == 0) {
                return buf;
        }
        if (c_isspace(buf[len-1])) {
                buf[len-1] = '\0';
        }

        return buf;
}

static bool parse_param(char *buf,
                        bool (*pfunc)(const char *name, const char *value,
                                      void *private_data),
                        void *private_data)
{
        char *equals;
        char *name, *value;
        size_t len;

        equals = strchr(buf, '=');
        if (equals == NULL) {
                return true;
        }
        *equals = '\0';

        name = trim_one_space(buf);
        len = strlen(buf);
        if (len == 0) {
                return false;
        }

        value = trim_one_space(equals+1);

        return pfunc(name, value, private_data);
}

bool tini_parse(FILE *f,
                bool (*sfunc)(const char *section, void *private_data),
                bool (*pfunc)(const char *name, const char *value,
                              void *private_data),
                void *private_data)
{
        char *buf;
        size_t buflen;

        buflen = 256;

        buf = malloc(buflen);
        if (buf == NULL) {
                return false;
        }

        while (true) {
                int ret;
                bool ok;

                ret = get_line(f, &buf, &buflen);

                if (ret == ENOENT) {
                        /* No lines anymore */
                        break;
                }

                if (ret != 0) {
                        /* Real error */
                        free(buf);
                        return false;
                }

                switch(buf[0]) {
                case 0:
                        continue;
                        break;
                case '[':
                        ok = parse_section(buf, sfunc, private_data);
                        break;
                default:
                        ok = parse_param(buf, pfunc, private_data);
                        break;
                }

                if (!ok) {
                        free(buf);
                        return false;
                }
        }
        free(buf);
        return true;
}