/*
 * Copyright (c) 2000, Boris Popov
 * All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Boris Popov.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * 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.
 *
 * $Id: rcfile.c,v 1.1.1.2 2001/07/06 22:38:43 conrad Exp $
 */
/*
 * Copyright 2018 Nexenta Systems, Inc.  All rights reserved.
 */

#include <fcntl.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/stat.h>

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <synch.h>
#include <unistd.h>
#include <pwd.h>
#include <libintl.h>

#include <cflib.h>
#include "rcfile_priv.h"

#include <assert.h>

#if 0 /* before SMF */
#define SMB_CFG_FILE    "/etc/nsmb.conf"
#define OLD_SMB_CFG_FILE        "/usr/local/etc/nsmb.conf"
#endif

extern int smb_debug;

static struct rcfile *rc_cachelookup(const char *filename);
static struct rcsection *rc_findsect(struct rcfile *rcp, const char *sectname);
static struct rcsection *rc_addsect(struct rcfile *rcp, const char *sectname);
static int              rc_freesect(struct rcfile *rcp, struct rcsection *rsp);
static struct rckey *rc_sect_findkey(struct rcsection *rsp, const char *key);
static struct rckey *rc_sect_addkey(struct rcsection *rsp, const char *name,
    const char *value);
static void rc_key_free(struct rckey *p);
static void rc_parse(struct rcfile *rcp);

/* lock for the variables below */
mutex_t rcfile_mutex = DEFAULTMUTEX;

SLIST_HEAD(rcfile_head, rcfile);
static struct rcfile_head pf_head = {NULL};
struct rcfile *smb_rc;
int home_nsmbrc;
int insecure_nsmbrc;

/*
 * open rcfile and load its content, if already open - return previous handle
 */
static int
rc_open(const char *filename, const char *mode, struct rcfile **rcfile)
{
        struct stat statbuf;
        struct rcfile *rcp;
        FILE *f;

        assert(MUTEX_HELD(&rcfile_mutex));

        rcp = rc_cachelookup(filename);
        if (rcp) {
                *rcfile = rcp;
                return (0);
        }
        f = fopen(filename, mode);
        if (f == NULL)
                return (errno);
        insecure_nsmbrc = 0;
        if (fstat(fileno(f), &statbuf) >= 0 &&
            (statbuf.st_mode & 077) != 0)
                insecure_nsmbrc = 1;
        rcp = malloc(sizeof (struct rcfile));
        if (rcp == NULL) {
                fclose(f);
                return (ENOMEM);
        }
        bzero(rcp, sizeof (struct rcfile));
        rcp->rf_name = strdup(filename);
        rcp->rf_f = f;
        SLIST_INSERT_HEAD(&pf_head, rcp, rf_next);
        rc_parse(rcp);
        *rcfile = rcp;
        return (0);
}

static int
rc_merge(const char *filename, struct rcfile **rcfile)
{
        struct stat statbuf;
        struct rcfile *rcp = *rcfile;
        FILE *f, *t;

        assert(MUTEX_HELD(&rcfile_mutex));

        insecure_nsmbrc = 0;
        if (rcp == NULL) {
                return (rc_open(filename, "r", rcfile));
        }
        f = fopen(filename, "r");
        if (f == NULL)
                return (errno);
        insecure_nsmbrc = 0;
        if (fstat(fileno(f), &statbuf) >= 0 &&
            (statbuf.st_mode & 077) != 0)
                insecure_nsmbrc = 1;
        t = rcp->rf_f;
        rcp->rf_f = f;
        rc_parse(rcp);
        rcp->rf_f = t;
        fclose(f);
        return (0);
}

/*
 * Like rc_open, but creates a temporary file and
 * reads the sharectl settings into it.
 * The file is deleted when we close it.
 */
static int
rc_open_sharectl(struct rcfile **rcfile)
{
        static char template[24] = "/tmp/smbfsXXXXXX";
        struct rcfile *rcp = NULL;
        FILE *fp = NULL;
        int err;
        int fd = -1;

        assert(MUTEX_HELD(&rcfile_mutex));

        fd = mkstemp(template);
        if (fd < 0) {
                err = errno;
                goto errout;
        }

        fp = fdopen(fd, "w+");
        if (fp == NULL) {
                err = errno;
                close(fd);
                goto errout;
        }
        fd = -1; /* The fp owns this fd now. */

        /*
         * Get smbfs sharectl settings into the file.
         */
        if ((err = rc_scf_get_sharectl(fp)) != 0)
                goto errout;

        rcp = malloc(sizeof (struct rcfile));
        if (rcp == NULL) {
                err = ENOMEM;
                goto errout;
        }
        bzero(rcp, sizeof (struct rcfile));

        rcp->rf_name = strdup(template);
        if (rcp->rf_name == NULL) {
                err = ENOMEM;
                goto errout;
        }
        rcp->rf_f = fp;
        rcp->rf_flags = RCFILE_DELETE_ON_CLOSE;

        SLIST_INSERT_HEAD(&pf_head, rcp, rf_next);
        insecure_nsmbrc = 0;
        rc_parse(rcp);
        *rcfile = rcp;
        /* fclose(f) in rc_close */
        return (0);

errout:
        if (rcp != NULL)
                free(rcp);
        if (fp != NULL) {
                fclose(fp);
                fd = -1;
        }
        if (fd != -1)
                close(fd);

        return (err);
}


static int
rc_close(struct rcfile *rcp)
{
        struct rcsection *p, *n;

        mutex_lock(&rcfile_mutex);

        fclose(rcp->rf_f);
        if (rcp->rf_flags & RCFILE_DELETE_ON_CLOSE)
                (void) unlink(rcp->rf_name);

        for (p = SLIST_FIRST(&rcp->rf_sect); p; ) {
                n = p;
                p = SLIST_NEXT(p, rs_next);
                rc_freesect(rcp, n);
        }
        free(rcp->rf_name);
        SLIST_REMOVE(&pf_head, rcp, rcfile, rf_next);
        free(rcp);

        mutex_unlock(&rcfile_mutex);
        return (0);
}

static struct rcfile *
rc_cachelookup(const char *filename)
{
        struct rcfile *p;

        assert(MUTEX_HELD(&rcfile_mutex));

        SLIST_FOREACH(p, &pf_head, rf_next)
                if (strcmp(filename, p->rf_name) == 0)
                        return (p);
        return (0);
}

static struct rcsection *
rc_findsect(struct rcfile *rcp, const char *sectname)
{
        struct rcsection *p;

        assert(MUTEX_HELD(&rcfile_mutex));

        SLIST_FOREACH(p, &rcp->rf_sect, rs_next)
                if (strcasecmp(p->rs_name, sectname) == 0)
                        return (p);
        return (NULL);
}

static struct rcsection *
rc_addsect(struct rcfile *rcp, const char *sectname)
{
        struct rcsection *p;

        assert(MUTEX_HELD(&rcfile_mutex));

        p = rc_findsect(rcp, sectname);
        if (p)
                return (p);
        p = malloc(sizeof (*p));
        if (!p)
                return (NULL);
        p->rs_name = strdup(sectname);
        SLIST_INIT(&p->rs_keys);
        SLIST_INSERT_HEAD(&rcp->rf_sect, p, rs_next);
        return (p);
}

static int
rc_freesect(struct rcfile *rcp, struct rcsection *rsp)
{
        struct rckey *p, *n;

        assert(MUTEX_HELD(&rcfile_mutex));

        SLIST_REMOVE(&rcp->rf_sect, rsp, rcsection, rs_next);
        for (p = SLIST_FIRST(&rsp->rs_keys); p; ) {
                n = p;
                p = SLIST_NEXT(p, rk_next);
                rc_key_free(n);
        }
        free(rsp->rs_name);
        free(rsp);
        return (0);
}

static struct rckey *
rc_sect_findkey(struct rcsection *rsp, const char *keyname)
{
        struct rckey *p;

        assert(MUTEX_HELD(&rcfile_mutex));

        SLIST_FOREACH(p, &rsp->rs_keys, rk_next)
                if (strcmp(p->rk_name, keyname) == 0)
                        return (p);
        return (NULL);
}

static struct rckey *
rc_sect_addkey(struct rcsection *rsp, const char *name, const char *value)
{
        struct rckey *p;

        assert(MUTEX_HELD(&rcfile_mutex));

        p = rc_sect_findkey(rsp, name);
        if (!p) {
                p = malloc(sizeof (*p));
                if (!p)
                        return (NULL);
                SLIST_INSERT_HEAD(&rsp->rs_keys, p, rk_next);
                p->rk_name = strdup(name);
                p->rk_value = value ? strdup(value) : strdup("");
        }
        return (p);
}

#if 0
void
rc_sect_delkey(struct rcsection *rsp, struct rckey *p)
{

        SLIST_REMOVE(&rsp->rs_keys, p, rckey, rk_next);
        rc_key_free(p);
}
#endif

static void
rc_key_free(struct rckey *p)
{
        free(p->rk_value);
        free(p->rk_name);
        free(p);
}


static char *minauth_values[] = {
        "none",
        "lm",
        "ntlm",
        "ntlmv2",
        "kerberos",
        NULL
};

static int
eval_minauth(char *auth)
{
        int i;

        for (i = 0; minauth_values[i]; i++)
                if (strcmp(auth, minauth_values[i]) == 0)
                        return (i);
        return (-1);
}

/*
 * Ensure that "minauth" is set to the highest level
 */
/*ARGSUSED*/
static void
set_value(struct rcfile *rcp, struct rcsection *rsp, struct rckey *rkp,
    char *ptr)
{
        int now, new;
#ifdef DEBUG
        char *from = "SMF";

        if (home_nsmbrc != 0)
                from = "user file";
#endif

        if (strcmp(rkp->rk_name, "minauth") == 0) {
                now = eval_minauth(rkp->rk_value);
                new = eval_minauth(ptr);
                if (new <= now) {
#ifdef DEBUG
                        if (smb_debug)
                                fprintf(stderr,
                                    "set_value: rejecting %s=%s"
                                    " in %s from %s\n",
                                    rkp->rk_name, ptr,
                                    rsp->rs_name, from);
#endif
                        return;
                }
        }
#ifdef DEBUG
        if (smb_debug)
                fprintf(stderr,
                    "set_value: applying %s=%s in %s from %s\n",
                    rkp->rk_name, ptr, rsp->rs_name, from);
#endif
        rkp->rk_value = strdup(ptr);
}


/* states in rc_parse */
enum { stNewLine, stHeader, stSkipToEOL, stGetKey, stGetValue};

static void
rc_parse(struct rcfile *rcp)
{
        FILE *f = rcp->rf_f;
        int state = stNewLine, c;
        struct rcsection *rsp = NULL;
        struct rckey *rkp = NULL;
        char buf[2048];
        char *next = buf, *last = &buf[sizeof (buf)-1];

        assert(MUTEX_HELD(&rcfile_mutex));

        while ((c = getc(f)) != EOF) {
                if (c == '\r')
                        continue;
                if (state == stNewLine) {
                        next = buf;
                        if (isspace(c))
                                continue;       /* skip leading junk */
                        if (c == '[') {
                                state = stHeader;
                                rsp = NULL;
                                continue;
                        }
                        if (c == '#' || c == ';') {
                                state = stSkipToEOL;
                        } else {                /* something meaningfull */
                                state = stGetKey;
                        }
                }
                /* ignore long lines */
                if (state == stSkipToEOL || next == last) {
                        if (c == '\n') {
                                state = stNewLine;
                                next = buf;
                        }
                        continue;
                }
                if (state == stHeader) {
                        if (c == ']') {
                                *next = 0;
                                next = buf;
                                rsp = rc_addsect(rcp, buf);
                                state = stSkipToEOL;
                        } else
                                *next++ = c;
                        continue;
                }
                if (state == stGetKey) {
                        /* side effect: 'key name=' */
                        if (c == ' ' || c == '\t')
                                continue;       /* become 'keyname=' */
                        if (c == '\n') {        /* silently ignore ... */
                                state = stNewLine;
                                continue;
                        }
                        if (c != '=') {
                                *next++ = c;
                                continue;
                        }
                        *next = 0;
                        if (rsp == NULL) {
                                fprintf(stderr, dgettext(TEXT_DOMAIN,
                                    "Key '%s' defined before section\n"), buf);
                                state = stSkipToEOL;
                                continue;
                        }
                        if (home_nsmbrc != 0 && (
                            strcmp(buf, "nbns") == 0 ||
                            strcmp(buf, "nbns_enable") == 0 ||
                            strcmp(buf, "nbns_broadcast") == 0)) {
                                fprintf(stderr, dgettext(TEXT_DOMAIN,
                                    "option %s may not be set "
                                    "in user .nsmbrc file\n"), buf);
                                next = buf;
                                state = stNewLine;
                                continue;
                        }
                        if (insecure_nsmbrc != 0 &&
                            strcmp(buf, "password") == 0) {
                                fprintf(stderr, dgettext(TEXT_DOMAIN,
                                    "Warning: .nsmbrc file not secure, "
                                    "ignoring passwords\n"));
                                next = buf;
                                state = stNewLine;
                                continue;
                        }
                        rkp = rc_sect_addkey(rsp, buf, NULL);
                        next = buf;
                        state = stGetValue;
                        continue;
                }
                /* only stGetValue left */
                if (state != stGetValue) {
                        fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "Well, I can't parse file '%s'\n"), rcp->rf_name);
                        state = stSkipToEOL;
                }
                if (c != '\n') {
                        *next++ = c;
                        continue;
                }
                *next = 0;
                set_value(rcp, rsp, rkp, buf);
                state = stNewLine;
                rkp = NULL;
        }       /* while */
        if (c == EOF && state == stGetValue) {
                *next = 0;
                set_value(rcp, rsp, rkp, buf);
        }
}

int
rc_getstringptr(struct rcfile *rcp, const char *section, const char *key,
        char **dest)
{
        struct rcsection *rsp;
        struct rckey *rkp;
        int err;

        mutex_lock(&rcfile_mutex);

        *dest = NULL;
        rsp = rc_findsect(rcp, section);
        if (!rsp) {
                err = ENOENT;
                goto out;
        }
        rkp = rc_sect_findkey(rsp, key);
        if (!rkp) {
                err = ENOENT;
                goto out;
        }
        *dest = rkp->rk_value;
        err = 0;

out:
        mutex_unlock(&rcfile_mutex);
        return (err);
}

int
rc_getstring(struct rcfile *rcp, const char *section, const char *key,
        size_t maxlen, char *dest)
{
        char *value;
        int error;

        error = rc_getstringptr(rcp, section, key, &value);
        if (error)
                return (error);
        if (strlen(value) >= maxlen) {
                fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "line too long for key '%s' in section '%s', max = %d\n"),
                    key, section, maxlen);
                return (EINVAL);
        }
        strcpy(dest, value);
        return (0);
}

int
rc_getint(struct rcfile *rcp, const char *section, const char *key, int *value)
{
        struct rcsection *rsp;
        struct rckey *rkp;
        int err;

        mutex_lock(&rcfile_mutex);

        rsp = rc_findsect(rcp, section);
        if (!rsp) {
                err = ENOENT;
                goto out;
        }
        rkp = rc_sect_findkey(rsp, key);
        if (!rkp) {
                err = ENOENT;
                goto out;
        }
        errno = 0;
        *value = strtol(rkp->rk_value, NULL, 0);
        if ((err = errno) != 0) {
                fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "invalid int value '%s' for key '%s' in section '%s'\n"),
                    rkp->rk_value, key, section);
        }

out:
        mutex_unlock(&rcfile_mutex);
        return (err);
}

/*
 * 1,yes,true
 * 0,no,false
 */
int
rc_getbool(struct rcfile *rcp, const char *section, const char *key, int *value)
{
        struct rcsection *rsp;
        struct rckey *rkp;
        char *p;
        int err;

        mutex_lock(&rcfile_mutex);

        rsp = rc_findsect(rcp, section);
        if (!rsp) {
                err = ENOENT;
                goto out;
        }
        rkp = rc_sect_findkey(rsp, key);
        if (!rkp) {
                err = ENOENT;
                goto out;
        }
        p = rkp->rk_value;
        while (*p && isspace(*p)) p++;
        if (*p == '0' ||
            strcasecmp(p, "no") == 0 ||
            strcasecmp(p, "false") == 0) {
                *value = 0;
                err = 0;
                goto out;
        }
        if (*p == '1' ||
            strcasecmp(p, "yes") == 0 ||
            strcasecmp(p, "true") == 0) {
                *value = 1;
                err = 0;
                goto out;
        }
        fprintf(stderr, dgettext(TEXT_DOMAIN,
            "invalid boolean value '%s' for key '%s' in section '%s' \n"),
            p, key, section);
        err = EINVAL;

out:
        mutex_unlock(&rcfile_mutex);
        return (err);
}

#ifdef DEBUG
void
dump_props(char *where)
{
        struct rcsection *rsp = NULL;
        struct rckey *rkp = NULL;

        fprintf(stderr, "Settings %s\n", where);
        SLIST_FOREACH(rsp, &smb_rc->rf_sect, rs_next) {
                fprintf(stderr, "section=%s\n", rsp->rs_name);
                fflush(stderr);

                SLIST_FOREACH(rkp, &rsp->rs_keys, rk_next) {
                        fprintf(stderr, "  key=%s, value=%s\n",
                            rkp->rk_name, rkp->rk_value);
                        fflush(stderr);
                }
        }
}
#endif

/*
 * first parse "sharectl get smbfs, then $HOME/.nsmbrc
 * This is called by library consumers (commands)
 */
int
smb_open_rcfile(char *home)
{
        char *fn;
        int len, error = 0;

        mutex_lock(&rcfile_mutex);

        smb_rc = NULL;
#if 0   /* before SMF */
        fn = SMB_CFG_FILE;
        error = rc_open(fn, &smb_rc);
#else
        fn = "(sharectl get smbfs)";
        error = rc_open_sharectl(&smb_rc);
#endif
        if (error != 0 && error != ENOENT) {
                /* Error from fopen. strerror is OK. */
                fprintf(stderr, dgettext(TEXT_DOMAIN,
                    "Can't open %s: %s\n"), fn, strerror(errno));
        }
#ifdef DEBUG
        if (smb_debug)
                dump_props(fn);
#endif

        if (home) {
                len = strlen(home) + 20;
                fn = malloc(len);
                snprintf(fn, len, "%s/.nsmbrc", home);
                home_nsmbrc = 1;
                error = rc_merge(fn, &smb_rc);
                if (error != 0 && error != ENOENT) {
                        fprintf(stderr, dgettext(TEXT_DOMAIN,
                            "Can't open %s: %s\n"), fn, strerror(errno));
                }
                home_nsmbrc = 0;
#ifdef DEBUG
                if (smb_debug)
                        dump_props(fn);
#endif
                free(fn);
        }

        /* Mostly ignore error returns above. */
        if (smb_rc == NULL)
                error = ENOENT;
        else
                error = 0;

        mutex_unlock(&rcfile_mutex);

        return (error);
}

/*
 * This is called by library consumers (commands)
 */
void
smb_close_rcfile(void)
{
        struct rcfile *rcp;

        if ((rcp = smb_rc) != NULL) {
                smb_rc = NULL;
                rc_close(rcp);
        }
}