/*

 * Dropbear - a SSH2 server

 *

 * Copyright (c) 2023 TJ Kolev

 * All rights reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE. */

#include "dbutil.h"

#include "runopts.h"

#if DROPBEAR_USE_SSH_CONFIG

#define TOKEN_CHARS " =\t\n"

static const size_t MAX_CONF_LINE = 200;

typedef enum {

  opHost,

  opHostName,

  opHostPort,

  opLoginUser,

  opIdentityFile,

} cfg_option;

static const struct {

  const char *name;

  cfg_option option;

}

config_options[] = {

  /* Start of config section. */

  { "host", opHost },

  { "hostname", opHostName },

  { "port", opHostPort },

  { "user", opLoginUser },

  { "identityfile", opIdentityFile },

};

void read_config_file(char* filename, FILE* config_file, cli_runopts* options) {

  char *line = NULL;

  int linenum = 0;

  buffer *buf = NULL;

  char* cfg_key;

  char* cfg_val;

  char* saveptr;

  int in_host_section = 0;

  DEBUG1(("Reading '%.200s'", filename));

  buf = buf_new(MAX_CONF_LINE);

  line = buf->data;

  while (buf_getline(buf, config_file) == DROPBEAR_SUCCESS) {

    char* commentStart = NULL;

    cfg_option cfg_opt;

    int found;

    size_t i;

    /* Update line number counter. */

    linenum++;

    /* Add nul terminator */

    if (buf->len == buf->size) {

      dropbear_exit("Long line %s:%d", filename, linenum);

    }

    buf_setpos(buf, buf->len);

    buf_putbyte(buf, '\0');

    buf_setpos(buf, 0);

    commentStart = strchr(line, '#');

    if (NULL != commentStart) {

      *commentStart = '\0'; /* Drop the comments. */

    }

    cfg_key = strtok_r(line, TOKEN_CHARS, &saveptr);

    if (NULL == cfg_key) {

      continue;

    }

    found = 0;

    for (i = 0; i < ARRAY_SIZE(config_options); i++) {

      if (0 == strcasecmp(cfg_key, config_options[i].name)) {

        cfg_opt = config_options[i].option;

        found = 1;

        break;

      }

    }

    if (!found) {

      dropbear_exit("Unsupported option %s at %s:%d", cfg_key, filename, linenum);

    }

    cfg_val = strtok_r(NULL, TOKEN_CHARS, &saveptr);

    if (NULL == cfg_val) {

      dropbear_exit("Missing value for %s at %s:%d", cfg_key, filename, linenum);

    }

    if (in_host_section) {

      switch (cfg_opt) {

        case opHost: {

          /* Hit the next host section. Done reading config. */

          goto outloop;

        }

        case opHostName: {

          /* The host name is the alias given on the command line.

           * Set the actual remote host specified in the config.

           */

          m_free(options->remotehost);

          options->remotehost = m_strdup(cfg_val);

          options->remotehostfixed = 1; /* Subsequent command line parsing should leave it alone. */

          break;

        }

        case opHostPort: {

          m_free(options->remoteport);

          options->remoteport = m_strdup(cfg_val);

          break;

        }

        case opLoginUser: {

          m_free(options->username);

          options->username = m_strdup(cfg_val);

          break;

        }

        case opIdentityFile: {

#if DROPBEAR_CLI_PUBKEY_AUTH

          char* key_file_path;

          if (strncmp(cfg_val, "~/", 2) == 0) {

            key_file_path = expand_homedir_path(cfg_val);

          } else if (cfg_val[0] != '/') {

            char* config_dir = dirname(filename);

            int path_len = strlen(config_dir) + strlen(cfg_val) + 10;

            key_file_path = m_malloc(path_len);

            snprintf(key_file_path, path_len, "%s/%s", config_dir, cfg_val);

          } else {

            key_file_path = m_strdup(cfg_val);

          }

          loadidentityfile(key_file_path, 1);

          m_free(key_file_path);

#else

          dropbear_exit("identityfile isn't supported in %s", filename);

#endif

          break;

        }

      }

    }

    else

    {

      if (opHost != cfg_opt || 0 != strcmp(cfg_val, options->remotehost)) {

        /* Not our host section. */

        continue;

      }

      in_host_section = 1;

    }

  }

outloop:

  buf_free(buf);

}

#endif /* DROPBEAR_USE_SSH_CONFIG */