rip_music_unix.cpp

/*
       _________ __                 __
      /   _____//  |_____________ _/  |______     ____  __ __  ______
      \_____  \\   __\_  __ \__  \\   __\__  \   / ___\|  |  \/  ___/
      /        \|  |  |  | \// __ \|  |  / __ \_/ /_/  >  |  /\___ |
     /_______  /|__|  |__|  (____  /__| (____  /\___  /|____//____  >
             \/                  \/          \//_____/            \/
  ______________________                           ______________________
                        T H E   W A R   B E G I N S
         Stratagus - A free fantasy real time strategy game engine

    rip_music_unix.c - rip audio CD on Unix with cdparanoia
    Copyright (C) 2011  Pali Rohár <pali.rohar@gmail.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>
#include <libgen.h>

#include <mntent.h>

#include "rip_music.h"

static char * find_mnt_dir(const char * dir) {

	char save_cwd[PATH_MAX];
	char last_cwd[PATH_MAX];
	char cwd[PATH_MAX];
	char * mnt_dir = NULL;
	struct stat st;
	__dev_t last_dev;
	__ino_t last_ino;

	if ( ! getcwd(save_cwd, sizeof(save_cwd)) ) {

		fprintf(stderr, "Error: Cannot store working directory: %s\n", strerror(errno));
		return NULL;

	}

	if ( stat(dir, &st) != 0 ) {

		fprintf(stderr, "Error: Cannot stat %s: %s\n", dir, strerror(errno));
		return NULL;

	}

	if ( chdir(dir) == -1 ) {

		fprintf(stderr, "Error: Cannot change directory to %s: %s\n", dir, strerror(errno));
		return NULL;

	}

	if ( ! getcwd(last_cwd, sizeof(last_cwd)) ) {

		fprintf(stderr, "Error: Cannot get working directory: %s\n", strerror(errno));

		if ( chdir(save_cwd) == -1 )
			fprintf(stderr, "Error: Cannot restore working directory: %s\n", strerror(errno));

		return NULL;

	}

	last_dev = st.st_dev;
	last_ino = st.st_ino;

	while ( 1 ) {

		if ( chdir("..") == -1 ) {

			fprintf(stderr, "Error: Cannot change working directory: %s\n", strerror(errno));
			break;

		}

		if ( ! getcwd(cwd, sizeof(cwd)) ) {

			fprintf(stderr, "Error: Cannot get working directory: %s\n", strerror(errno));
			break;

		}

		if ( stat(cwd, &st) != 0 ) {

			fprintf(stderr, "Error: Cannot stat %s: %s\n", cwd, strerror(errno));
			break;

		}

		if ( last_dev != st.st_dev || last_ino == st.st_ino ) {

			mnt_dir = strdup(last_cwd);
			break;

		}

		if ( strcmp(cwd, "/") == 0 ) {

			mnt_dir = strdup("/");
			break;

		}

		last_dev = st.st_dev;
		last_ino = st.st_ino;
		strcpy(last_cwd, cwd);

	}

	if ( chdir(save_cwd) == -1 )
		fprintf(stderr, "Error: Cannot restore working directory: %s\n", strerror(errno));

	return mnt_dir;

}

static char * find_dev(const char * mnt_dir) {

	struct mntent * mnt;
	char * dev = NULL;
	FILE * file;

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

	if ( ! file ) {

		fprintf(stderr, "Error: Cannot open file /etc/mtab: %s\n", strerror(errno));
		return NULL;

	}

	while ( ( mnt = getmntent(file) ) ) {

		if ( strcmp(mnt->mnt_dir, mnt_dir) == 0 ) {

			dev = strdup(mnt->mnt_fsname);
			break;

		}

	}

	endmntent(file);

	return dev;

}

static int spawnvp(const char * file, char * const argv[]) {

	int status;
	pid_t pid = fork();

	if ( pid < 0 ) {

		fprintf(stderr, "Error: Cannot fork: %s\n", strerror(errno));
		return -errno;

	}

	if ( pid == 0 ) {

		execvp(file, argv);
		fprintf(stderr, "Error: Cannot exec: %s\n", strerror(errno));
		_exit(errno);

	}

	if ( waitpid(pid, &status, 0) == pid )
		return WEXITSTATUS(status);
	else
		return -1;

}

int RipMusic(int expansion_cd, const char * data_dir, const char * dest_dir) {

	struct stat st;
	char * args[6] = { (char *)"cdparanoia", (char *)"-d", NULL, (char *)"-v", (char *)"-Q", NULL };
	char * mnt_dir;
	char * dev;
	int count = 0;
	int i;

	if ( stat(data_dir, &st) != 0 ) {

		fprintf(stderr, "Error: Cannot stat %s: %s\n", data_dir, strerror(errno));
		return 1;

	}

	mnt_dir = find_mnt_dir(data_dir);

	if ( ! mnt_dir ) {

		fprintf(stderr, "Error: Cannot find mount dir\n");
		return 1;

	}

	dev = find_dev(mnt_dir);

	if ( ! dev ) {

		fprintf(stderr, "Error: Cannot find device for mount dir %s\n", mnt_dir);
		free(mnt_dir);
		return 1;

	}

	free(mnt_dir);

	printf("Found CD-ROM device: %s\n", dev);
	fflush(stdout);

	args[2] = dev;

	if ( spawnvp(args[0], args) != 0 ) {

		free(dev);
		return 1;

	}

	for ( i = 0; MusicNames[i]; ++i ) {

		char num[3];
		char file[PATH_MAX];

		if ( ! expansion_cd && ! MusicNames[i+1] )
			break;

		snprintf(num, sizeof(num), "%d", i+2);
		snprintf(file, sizeof(file), "%s/%s.wav", dest_dir, MusicNames[i]);

		args[3] = num;
		args[4] = file;

		if ( spawnvp(args[0], args) == 0 )
			++count;

	}

	free(dev);

	if ( count == 0 )
		return 1;
	else
		return 0;

}