/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 2 -*- */
/*
 * Originally written by Alexander Vdolainen <avdolainen@gmail.com>
 */

#define _GNU_SOURCE

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <getopt.h>
#include <mntent.h>
#include <blkid/blkid.h>

#define TOOLMODE_CMD   1
#define TOOLMODE_INFO  2

static void __print_version(void)
{
  fprintf(stdout, "DSB user space daemon control tool version: 0.1\n\n");
  fprintf(stdout, "Copyright (c) 2015-2016 Alexander Vdolainen.\nEmail: avdolainen@gmail.com\n\n");

  return;
}

static void __print_help(void)
{
  fprintf(stdout, "Usage: dsbfcntl [options]\nOptions:\n");
  fprintf(stdout, " --file-info(-i)\t Get file information required to set rules.\n");
  fprintf(stdout, " --control-command(-c) \"<command>\"\t Command to send to the DSB userspace daemon.\n");
  fprintf(stdout, " --unix-socket-path(-u) <file>\t Use <file> as the unix socket name.\n");
  fprintf(stdout, " --help(-h)\t Print there help message\n");
  fprintf(stdout, " --version(-v)\t Print version information\n");
  fprintf(stdout, "\nFor further information check out provided documentation.\n");
  return;
}

static int __print_fileinfo(const char *fpath)
{
  int r = 0;
  struct stat buf;
  FILE* fstab = NULL;
  struct mntent *e;
  char *devname = NULL;
  char _fpath[4096];
  uint64_t inode_num = 0;
  blkid_probe pr;
  const char *uuid;

	r = stat(fpath, &buf);
	if(r) {
    fprintf(stderr, "FAILED: %s\n", strerror(r));
		return r;
	} else inode_num = buf.st_ino; /* get inode number */

	/* ok now we need to get full path if required */
	if(*fpath != '/') {
		snprintf(_fpath, 4096, "%s/%s", get_current_dir_name(), fpath);
	} else strcpy(_fpath, fpath);

  fprintf(stdout, "Full pathname: %s\n", _fpath);

	fstab = setmntent("/etc/mtab", "r");

	/* e->mnt_dir is our hitler, mnt_fsname is a device */
	while ((e = getmntent(fstab))) {
		if(strlen(_fpath) < strlen(e->mnt_dir)) {
			continue; /* not so interesting */
		} else if(!strncmp(_fpath, e->mnt_dir, strlen(e->mnt_dir))) {
			devname = strdup(e->mnt_fsname);
			if(!devname) { r = ENOMEM; goto __fini; }
		}
	}

	fprintf(stdout, "Root device of the file is: %s\n", devname);
	fprintf(stdout, "File object inode number is: %lu\n", inode_num);

	pr = blkid_new_probe_from_filename(devname);
  if(!pr) {
    r = EINVAL;
    fprintf(stderr, "FAILED: %s\n", strerror(r)); goto __fini;
  }

  blkid_do_probe(pr);
  blkid_probe_lookup_value(pr, "UUID", &uuid, NULL);

  fprintf(stdout, "Root device UUID=%s\n", uuid);

  blkid_free_probe(pr);

 __fini:
	endmntent(fstab);
  if(devname) free(devname);

	return r;
}

static int __execute_cmd(const char *unxsckpath, const char *ctrlcmd)
{
  int r = 0, c, s, len;
  char *buf = malloc(4096);
  struct sockaddr_un remote;

  if(!buf) return ENOMEM;

  if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
    r = errno;
    goto __fini0;
  }

  remote.sun_family = AF_UNIX;
  strcpy(remote.sun_path, unxsckpath);
  len = strlen(remote.sun_path) + sizeof(remote.sun_family);
  if (connect(s, (struct sockaddr *)&remote, len) == -1) {
    r = errno;
    goto __fini;
  }

  if(send(s, ctrlcmd, strlen(ctrlcmd), 0) == -1) {
    r = errno;
    goto __fini;
  }

  while((c = recv(s, buf, 4096, 0)) != 0) {
    if(c < 0) {
      r = errno;
      goto __fini;
    }
    fprintf(stdout, "%s", buf);
  }

 __fini:
  close(s);
 __fini0:
  free(buf);

  return r;
}

int main(int argc, char **argv)
{
	int toolmode = 0, c, r = 0;
	char *unxsckpath = NULL;
	char *ctrlcmd = NULL;
	char *fpath = NULL;

	while(1) {
		static struct option long_options[] = {
      /* These options a generic ones. */
      {"help", no_argument, NULL, 'h'}, /* print out help and version info */
      {"version", no_argument, NULL, 'v'}, /* just out a version info */
      /*  The following options about system. */
      {"control-command", required_argument, NULL, 'c'},
      {"unix-socket-path", required_argument, NULL, 'u'},
      {"file-info", required_argument, NULL, 'i'},
      {NULL, 0, NULL, 0},
    };
    /* getopt_long stores the option index here. */
    int option_index = 0;
		    if((c = getopt_long(argc, argv, "hvc:u:i:", long_options,
                        &option_index)) == -1) break;

    switch (c) {
    case 'h':
      __print_help();
      return 0;
      break;
    case 'v':
      __print_version();
      return 0;
      break;
    case 'c':
			if(!toolmode || toolmode == TOOLMODE_CMD) toolmode = TOOLMODE_CMD;
			else {
				fprintf(stderr, "Illegal mode given.\n");
				r = -EINVAL;
				goto __fails;
			}
			if(!(ctrlcmd = strdup(optarg)))				{ r = -ENOMEM; goto __fails; }
      break;
    case 'u':
			if(!toolmode || toolmode == TOOLMODE_CMD) toolmode = TOOLMODE_CMD;
			else {
				fprintf(stderr, "Illegal mode given.\n");
				r = -EINVAL;
				goto __fails;
			}
			if(!(unxsckpath = strdup(optarg)))				{ r = -ENOMEM; goto __fails; }
      break;
    case 'i':
			if(!toolmode || toolmode == TOOLMODE_INFO) toolmode = TOOLMODE_INFO;
			else {
				fprintf(stderr, "Illegal mode given.\n");
				r = -EINVAL;
				goto __fails;
			}
			if(!(fpath = strdup(optarg)))				{ r = -ENOMEM; goto __fails; }
      break;
    case '?':
      /* getopt_long already printed an error message. */
      break;
    default:
      abort();
    }

	}

	/* run it */
	switch(toolmode) {
	case TOOLMODE_CMD:
		if(!unxsckpath) {
			fprintf(stderr, "FAILED: Unix socket path doesn't pointed.\n");
			goto __einval;
		}
		if(!ctrlcmd) {
			fprintf(stderr, "FAILED: Command is absent.\n");
			goto __einval;
		}
		r = __execute_cmd(unxsckpath, ctrlcmd);
		break;
	case TOOLMODE_INFO:
		if(!fpath) {
			fprintf(stderr, "FAILED: No input filename(s).\n");
			goto __einval;
		}
		r = __print_fileinfo(fpath);
		break;
	default:
		fprintf(stderr, "FAILED: Incorrect options given.\n");
	__einval:
		__print_version();
		__print_help();

		return -EINVAL;
		break;
	}

 __fails:
	if(unxsckpath) free(unxsckpath);
	if(ctrlcmd) free(ctrlcmd);
	if(fpath) free(fpath);

  return r;
}