/*
 * Copyright (c) 1990 Jan-Simon Pendry
 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *      from: @(#)info_file.c   8.1 (Berkeley) 6/6/93
 *      $Id: info_file.c,v 1.9 2014/10/26 03:03:34 guenther Exp $
 */

/*
 * Get info from file
 */

#include "am.h"

#include <ctype.h>
#include <sys/stat.h>

#define MAX_LINE_LEN    2048

static int
read_line(char *buf, int size, FILE *fp)
{
        int done = 0;

        do {
                while (fgets(buf, size, fp)) {
                        int len = strlen(buf);

                        done += len;
                        if (len > 1 && buf[len-2] == '\\' &&
                            buf[len-1] == '\n') {
                                int ch;

                                buf += len - 2;
                                size -= len - 2;
                                *buf = '\n'; buf[1] = '\0';
                                /*
                                 * Skip leading white space on next line
                                 */
                                while ((ch = getc(fp)) != EOF &&
                                    isascii(ch) && isspace(ch))
                                        ;
                                (void) ungetc(ch, fp);
                        } else {
                                return done;
                        }
                }
        } while (size > 0 && !feof(fp));
        return done;
}

/*
 * Try to locate a key in a file
 */
static int
search_or_reload_file(FILE *fp, char *map, char *key, char **val, mnt_map *m,
    void (*fn)(mnt_map *m, char *, char *))
{
        char key_val[MAX_LINE_LEN];
        int chuck = 0;
        int line_no = 0;

        while (read_line(key_val, sizeof(key_val), fp)) {
                char *kp;
                char *cp;
                char *hash;
                int len = strlen(key_val);

                line_no++;

                /*
                 * Make sure we got the whole line
                 */
                if (key_val[len-1] != '\n') {
                        plog(XLOG_WARNING, "line %d in \"%s\" is too long",
                            line_no, map);
                        chuck = 1;
                } else {
                        key_val[len-1] = '\0';
                }

                /*
                 * Strip comments
                 */
                hash = strchr(key_val, '#');
                if (hash)
                        *hash = '\0';

                /*
                 * Find start of key
                 */
                for (kp = key_val;
                    isascii((unsigned char)*kp) && isspace((unsigned char)*kp);
                    kp++)
                        ;

                /*
                 * Ignore blank lines
                 */
                if (!*kp)
                        goto again;

                /*
                 * Find end of key
                 */
                for (cp = kp; *cp &&
                    (!isascii((unsigned char)*cp) || !isspace((unsigned char)*cp));
                    cp++)
                        ;

                /*
                 * Check whether key matches
                 */
                if (*cp)
                        *cp++ = '\0';

                if (fn || (*key == *kp && strcmp(key, kp) == 0)) {
                        while (isascii((unsigned char)*cp) &&
                            isspace((unsigned char)*cp))
                                cp++;
                        if (*cp) {
                                /*
                                 * Return a copy of the data
                                 */
                                char *dc = strdup(cp);
                                if (fn) {
                                        (*fn)(m, strdup(kp), dc);
                                } else {
                                        *val = dc;
#ifdef DEBUG
                                        dlog("%s returns %s", key, dc);
#endif /* DEBUG */
                                }
                                if (!fn)
                                        return 0;
                        } else {
                                plog(XLOG_USER, "%s: line %d has no value field",
                                    map, line_no);
                        }
                }

again:
                /*
                 * If the last read didn't get a whole line then
                 * throw away the remainder before continuing...
                 */
                if (chuck) {
                        while (fgets(key_val, sizeof(key_val), fp) &&
                            !strchr(key_val, '\n'))
                                        ;
                        chuck = 0;
                }
        }

        return fn ? 0 : ENOENT;
}

static FILE *
file_open(char *map, time_t *tp)
{
        FILE *mapf = fopen(map, "r");

        if (mapf && tp) {
                struct stat stb;

                if (fstat(fileno(mapf), &stb) < 0)
                        *tp = clocktime();
                else
                        *tp = stb.st_mtime;
        }
        return mapf;
}

int
file_init(char *map, time_t *tp)
{
        FILE *mapf = file_open(map, tp);

        if (mapf) {
                (void) fclose(mapf);
                return 0;
        }
        return errno;
}

int
file_reload(mnt_map *m, char *map, void (*fn)(mnt_map *, char *, char *))
{
        FILE *mapf = file_open(map, (time_t *) 0);

        if (mapf) {
                int error = search_or_reload_file(mapf, map, 0, 0, m, fn);
                (void) fclose(mapf);
                return error;
        }

        return errno;
}

int
file_search(mnt_map *m, char *map, char *key, char **pval, time_t *tp)
{
        time_t t;
        FILE *mapf = file_open(map, &t);

        if (mapf) {
                int error;
                if (*tp < t) {
                        *tp = t;
                        error = -1;
                } else {
                        error = search_or_reload_file(mapf, map, key, pval, 0, 0);
                }
                (void) fclose(mapf);
                return error;
        }

        return errno;
}

int
file_mtime(char *map, time_t *tp)
{
        FILE *mapf = file_open(map, tp);

        if (mapf) {
                (void) fclose(mapf);
                return 0;
        }

        return errno;
}