/*
 * Copyright (c) 2009-2011 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Alex Hornung <ahornung@gmail.com>
 *
 * 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 DragonFly Project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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 <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <err.h>

#include <libcryptsetup.h>
#include <tcplay_api.h>

#include "safe_mem.h"

#define _iswhitespace(X)        ((((X) == ' ') || ((X) == '\t'))?1:0)

#define CRYPTDISKS_START        1
#define CRYPTDISKS_STOP         2

struct generic_opts {
        char            *device;
        char            *map_name;
        char            *passphrase;
        const char      *keyfiles[256];
        int             nkeyfiles;
        int             ntries;
        unsigned long long      timeout;
};

static void syntax_error(const char *, ...) __printflike(1, 2);

static int line_no = 1;

static int iswhitespace(char c)
{
        return _iswhitespace(c);
}

static int iscomma(char c)
{
        return (c == ',');
}

static int yesDialog(char *msg __unused)
{
        return 1;
}

static void cmdLineLog(int level __unused, char *msg)
{
        printf("%s", msg);
}

static struct interface_callbacks cmd_icb = {
        .yesDialog = yesDialog,
        .log = cmdLineLog,
};

static void
syntax_error(const char *fmt, ...)
{
        char buf[1024];
        va_list ap;

        va_start(ap, fmt);
        vsnprintf(buf, sizeof(buf), fmt, ap);
        va_end(ap);
        errx(1, "crypttab: syntax error on line %d: %s\n", line_no, buf);
}


static int
entry_check_num_args(char **tokens, int num)
{
        int i;

        for (i = 0; tokens[i] != NULL; i++)
                ;

        if (i < num) {
                syntax_error("at least %d tokens were expected but only %d "
                    "were found", num, i);
                return 1;
        }
        return 0;
}

static int
line_tokenize(char *buffer, int (*is_sep)(char), char comment_char, char **tokens)
{
        int c, n, i;
        int quote = 0;

        i = strlen(buffer) + 1;
        c = 0;

        /* Skip leading white-space */
        while ((_iswhitespace(buffer[c])) && (c < i)) c++;

        /*
         * If this line effectively (after indentation) begins with the comment
         * character, we ignore the rest of the line.
         */
        if (buffer[c] == comment_char)
                return 0;

        tokens[0] = &buffer[c];
        for (n = 1; c < i; c++) {
                if (buffer[c] == '"') {
                        quote = !quote;
                        if (quote) {
                                if ((c >= 1) && (&buffer[c] != tokens[n-1])) {
#if 0
                                        syntax_error("stray opening quote not "
                                            "at beginning of token");
                                        /* NOTREACHED */
#endif
                                } else {
                                        tokens[n-1] = &buffer[c+1];
                                }
                        } else {
                                if ((c < i-1) && (!is_sep(buffer[c+1]))) {
#if 0
                                        syntax_error("stray closing quote not "
                                            "at end of token");
                                        /* NOTREACHED */
#endif
                                } else {
                                        buffer[c] = '\0';
                                }
                        }
                }

                if (quote) {
                        continue;
                }

                if (is_sep(buffer[c])) {
                        buffer[c++] = '\0';
                        while ((_iswhitespace(buffer[c])) && (c < i)) c++;
                        tokens[n++] = &buffer[c--];
                }
        }
        tokens[n] = NULL;

        if (quote) {
                tokens[0] = NULL;
                return 0;
        }

        return n;
}

static int
parse_crypt_options(struct generic_opts *go, char *option)
{
        char    *parameter, *endptr;
        char    *buf;
        long    lval;
        unsigned long long ullval;
        int     noparam = 0;
        FILE    *fd;

        parameter = strchr(option, '=');
        noparam = (parameter == NULL);
        if (!noparam)
        {
                *parameter = '\0';
                ++parameter;
        }

        if (strcmp(option, "tries") == 0) {
                if (noparam)
                        syntax_error("The option 'tries' needs a parameter");
                        /* NOTREACHED */

                lval = strtol(parameter, &endptr, 10);
                if (*endptr != '\0')
                        syntax_error("The option 'tries' expects an integer "
                            "parameter, not '%s'", parameter);
                        /* NOTREACHED */

                go->ntries = (int)lval;
        } else if (strcmp(option, "timeout") == 0) {
                if (noparam)
                        syntax_error("The option 'timeout' needs a parameter");
                        /* NOTREACHED */

                ullval = strtoull(parameter, &endptr, 10);
                if (*endptr != '\0')
                        syntax_error("The option 'timeout' expects an integer "
                            "parameter, not '%s'", parameter);
                        /* NOTREACHED */

                go->timeout = ullval;
        } else if (strcmp(option, "keyscript") == 0) {
                size_t keymem_len = 8192;

                if (noparam)
                        syntax_error("The option 'keyscript' needs a parameter");
                        /* NOTREACHED */

                /* Allocate safe key memory */
                buf = alloc_safe_mem(keymem_len);
                if (buf == NULL)
                        err(1, "Could not allocate safe memory");
                        /* NOTREACHED */

                fd = popen(parameter, "r");
                if (fd == NULL)
                        syntax_error("The 'keyscript' file could not be run");
                        /* NOTREACHED */

                if ((fread(buf, 1, keymem_len, fd)) == 0)
                        syntax_error("The 'keyscript' program failed");
                        /* NOTREACHED */
                pclose(fd);

                /* Get rid of trailing new-line */
                if ((endptr = strrchr(buf, '\n')) != NULL)
                        *endptr = '\0';

                go->passphrase = buf;
        } else if (strcmp(option, "none") == 0) {
                /* Valid option, does nothing */
        } else {
                syntax_error("Unknown option: %s", option);
                /* NOTREACHED */
        }

        return 0;
}

static void
generic_opts_to_luks(struct crypt_options *co, struct generic_opts *go)
{
        if (go->nkeyfiles > 1)
                fprintf(stderr, "crypttab: Warning: LUKS only supports one "
                    "keyfile; on line %d\n", line_no);

        co->icb = &cmd_icb;
        co->tries = go->ntries;
        co->name = go->map_name;
        co->device = go->device;
        co->key_file = (go->nkeyfiles == 1) ? go->keyfiles[0] : NULL;
        co->passphrase = go->passphrase;
        co->timeout = go->timeout;
}

static int
entry_parser(char **tokens, char **options, int type)
{
        struct crypt_options co;
        tc_api_task tcplay_task;
        struct generic_opts go;
        int r, i, error, isluks;

        if (entry_check_num_args(tokens, 2) != 0)
                return 1;

        bzero(&go, sizeof(go));
        bzero(&co, sizeof(co));


        go.ntries = 3;
        go.map_name = tokens[0];
        go.device = tokens[1];

        /* (Try to) parse extra options */
        for (i = 0; options[i] != NULL; i++)
                parse_crypt_options(&go, options[i]);

        if ((tokens[2] != NULL) && (strcmp(tokens[2], "none") != 0)) {
                /* We got a keyfile */
                go.keyfiles[go.nkeyfiles++] = tokens[2];
        }

        generic_opts_to_luks(&co, &go);

        /*
         * Check whether the device is a LUKS-formatted device; otherwise
         * we assume its a TrueCrypt volume.
         */
        isluks = !crypt_isLuks(&co);

        if (!isluks) {
                if ((error = tc_api_init(0)) != 0) {
                        fprintf(stderr, "crypttab: line %d: tc_api could not "
                            "be initialized\n", line_no);
                        return 1;
                }
        }

        if (type == CRYPTDISKS_STOP) {
                if (isluks) {
                        /* Check if the device is active */
                        r = crypt_query_device(&co);

                        /* If r > 0, then the device is active */
                        if (r <= 0)
                                return 0;

                        /* Actually close the device */
                        crypt_remove_device(&co);
                } else {
                        /* Assume tcplay volume */
                        if ((tcplay_task = tc_api_task_init("unmap")) == NULL) {
                                fprintf(stderr, "tc_api_task_init failed.\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "dev", go.device))) {
                                fprintf(stderr, "tc_api_task_set dev failed\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "map_name",
                            go.map_name))) {
                                fprintf(stderr, "tc_api_task_set map_name failed\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_do(tcplay_task))) {
                                fprintf(stderr, "crypttab: line %d: device %s "
                                    "could not be unmapped: %s\n",
                                    line_no, go.device,
                                    tc_api_task_get_error(tcplay_task));
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_uninit(tcplay_task))) {
                                fprintf(stderr, "tc_api_task_uninit failed\n");
                                goto tcplay_err;
                        }

                }
        } else if (type == CRYPTDISKS_START) {
                /* Open the device */
                if (isluks) {
                        if ((error = crypt_luksOpen(&co)) != 0) {
                                fprintf(stderr, "crypttab: line %d: device %s "
                                    "could not be mapped/opened\n",
                                    line_no, co.device);
                                return 1;
                        }
                } else {
                        if ((tcplay_task = tc_api_task_init("map")) == NULL) {
                                fprintf(stderr, "tc_api_task_init failed.\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "dev", go.device))) {
                                fprintf(stderr, "tc_api_task_set dev failed\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "map_name",
                            go.map_name))) {
                                fprintf(stderr, "tc_api_task_set map_name failed\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "interactive",
                            (go.passphrase != NULL) ? 0 : 1))) {
                                fprintf(stderr, "tc_api_task_set map_name failed\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "retries",
                            go.ntries))) {
                                fprintf(stderr, "tc_api_task_set map_name failed\n");
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_set(tcplay_task, "timeout",
                            go.timeout))) {
                                fprintf(stderr, "tc_api_task_set map_name failed\n");
                                goto tcplay_err;
                        }

                        if (go.passphrase != NULL) {
                                if ((error = tc_api_task_set(tcplay_task, "passphrase",
                                    go.passphrase))) {
                                        fprintf(stderr, "tc_api_task_set map_name failed\n");
                                        goto tcplay_err;
                                }
                        }

                        for (i = 0; i < go.nkeyfiles; i++) {
                                if ((error = tc_api_task_set(tcplay_task, "keyfiles",
                                    go.keyfiles[i]))) {
                                        fprintf(stderr, "tc_api_task_set keyfile failed\n");
                                        goto tcplay_err;
                                }
                        }
                        if ((error = tc_api_task_do(tcplay_task))) {
                                fprintf(stderr, "crypttab: line %d: device %s "
                                    "could not be mapped/opened: %s\n",
                                    line_no, go.device,
                                    tc_api_task_get_error(tcplay_task));
                                goto tcplay_err;
                        }
                        if ((error = tc_api_task_uninit(tcplay_task))) {
                                fprintf(stderr, "tc_api_task_uninit failed\n");
                                goto tcplay_err;
                        }
                }
        }

        if (!isluks)
                tc_api_uninit();

        return 0;

tcplay_err:
        tc_api_uninit();
        return 1;
}

static int
process_line(FILE* fd, int type)
{
        char buffer[4096];
        char *tokens[256];
        char *options[256];
        int c, n, i = 0;
        int ret = 0;

        while (((c = fgetc(fd)) != EOF) && (c != '\n')) {
                buffer[i++] = (char)c;
                if (i == (sizeof(buffer) -1))
                        break;
        }
        buffer[i] = '\0';

        if (feof(fd) || ferror(fd))
                ret = 1;


        n = line_tokenize(buffer, &iswhitespace, '#', tokens);

        /*
         * If there are not enough arguments for any function or it is
         * a line full of whitespaces, we just return here. Or if a
         * quote wasn't closed.
         */
        if ((n < 2) || (tokens[0][0] == '\0'))
                return ret;

        /*
         * If there are at least 4 tokens, one of them (the last) is a list
         * of options.
         */
        if (n >= 4)
        {
                i = line_tokenize(tokens[3], &iscomma, '#', options);
                if (i == 0)
                        syntax_error("Invalid expression in options token");
                        /* NOTREACHED */
        }

        entry_parser(tokens, options, type);

        return ret;
}


int
main(int argc, char *argv[])
{
        FILE *fd;
        int ch, start = 0, stop = 0;

        while ((ch = getopt(argc, argv, "01")) != -1) {
                switch (ch) {
                case '1':
                        start = 1;
                        break;
                case '0':
                        stop = 1;
                        break;
                default:
                        break;
                }
        }

        argc -= optind;
        argv += optind;

        atexit(check_and_purge_safe_mem);

        if ((start && stop) || (!start && !stop))
                errx(1, "please specify exactly one of -0 and -1");

        fd = fopen("/etc/crypttab", "r");
        if (fd == NULL)
                err(1, "fopen");
                /* NOTREACHED */

        while (process_line(fd, (start) ? CRYPTDISKS_START : CRYPTDISKS_STOP) == 0)
                ++line_no;

        fclose(fd);
        return 0;
}