+/*
+ * DTMS Copyright (C) 2016 Eleni Maria Stea <elene.mst@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 3 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 <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+static int parse_args(int argc, char **argv);
+static void print_help();
+static int check_device(char *device_path);
+
+static int uid = -1;
+static char *player_path;
+static char *dev_path;
+
+#ifdef PREFIX
+static const char* player_arg = PREFIX "/share/dtms/dtms.mp3";
+#else
+static const char* player_arg = "data/dtms.mp3";
+#endif
+
+int main(int argc, char **argv)
+{
+ time_t last_touch_time = 0;
+ int fd;
+
+ if(parse_args(argc, argv) == -1)
+ return 1;
+
+ if(getuid() == 0 && uid == -1) {
+ fprintf(stderr, "It's a bad idea to run this program as root, either make it setuid-root, or use the -u option to specify an unprivileged user.\n");
+ return 1;
+ }
+
+ if(check_device(dev_path) == -1)
+ return 1;
+
+ if((fd = open(dev_path, O_RDONLY | O_NONBLOCK)) == -1) {
+ fprintf(stderr, "Failed to open device: %s, error: %s\n", dev_path, strerror(errno));
+ return 1;
+ }
+
+ if(uid == -1) {
+ uid = getuid();
+ }
+
+ if(seteuid(uid) == -1) {
+ perror("Set uid failed");
+ return 1;
+ }
+
+ if(!uid) {
+ if(player_path[0] != '/') {
+ fprintf(stderr, "If you run this program as root you should pass the absolute path to a valid mp3 player.\n");
+ return 1;
+ }
+ }
+
+ char *cmd = malloc(strlen(player_path) + 1 + strlen(player_arg) + 1);
+ sprintf(cmd, "%s %s", player_path, player_arg);
+
+ while(1) {
+ fd_set read_set;
+ FD_ZERO(&read_set);
+ FD_SET(fd, &read_set);
+
+ int res;
+ while((res = select(fd + 1, &read_set, 0, 0, 0)) == -1 && errno == EINTR);
+ if(res < 0) {
+ perror("Select failed");
+ break;
+ }
+ if(res == 0) //nothing to read
+ continue;
+
+ if(FD_ISSET(fd, &read_set)) {
+ char buf[1024];
+ time_t now = time(0);
+ while(read(fd, buf, sizeof buf) > 0);
+ if (now - last_touch_time > 2) {
+ system(cmd);
+ last_touch_time = now;
+ }
+ }
+ }
+
+ free(cmd);
+ close(fd);
+
+ return 0;
+}
+
+static int parse_args(int argc, char **argv)
+{
+ for(int i=1; i<argc; i++) {
+ if((strcmp(argv[i], "-h") == 0)) {
+ print_help();
+ exit(0);
+ }
+
+ else if((strcmp(argv[i], "-p") == 0)) {
+ if(argv[++i]) {
+ player_path = argv[i];
+ }
+ else {
+ fprintf(stderr, "Invalid path. Please give the absolute path to an mp3 player.\n");
+ return -1;
+ }
+ }
+
+ else if((strcmp(argv[i], "-u") == 0)) {
+ if(argv[++i]) {
+ struct passwd *passwd = getpwnam(argv[i]);
+ if(!passwd) {
+ fprintf(stderr, "Failed to get uid for: %s : %s.\n", argv[i], strerror(errno));
+ return -1;
+ }
+ uid = passwd->pw_uid;
+ if(uid == 0) {
+ fprintf(stderr, "You should pass an unprivileged username.\n");
+ return -1;
+ }
+ }
+ else {
+ fprintf(stderr, "Missing username.\n");
+ return -1;
+ }
+ }
+ else if((strcmp(argv[i], "-d") == 0)) {
+ if(argv[++i]) {
+ dev_path = argv[i];
+ }
+ else {
+ fprintf(stderr, "Invalid device file.\n");
+ return -1;
+ }
+ }
+ else {
+ fprintf(stderr, "Unknown argument: %s\n", argv[i]);
+ return -1;
+ }
+ }
+ return 0;
+}
+
+static void print_help()
+{
+ printf("Options:\n");
+ printf("-h, prints this help\n");
+ printf("-d, path to the device\n");
+ printf("-p, path to the mp3 player\n");
+ printf("-u. username of the user that runs the program\n");
+ printf("--------\n");
+ printf("Examples:\n");
+ printf("--------\n");
+ printf("./dtms -d /dev/usb/hiddev0 -u eleni -p /usr/bin/mpv\n");
+}
+
+static int check_device(char *device_path)
+{
+ struct stat sb;
+ if(stat(dev_path, &sb) == -1) {
+ perror("stat");
+ return -1;
+ }
+ if(((sb.st_mode & S_IFMT) != S_IFBLK) && ((sb.st_mode & S_IFMT) != S_IFCHR)) {
+ fprintf(stderr, "%s is not a device file.\n", device_path);
+ return -1;
+ }
+ return 0;
+}
projects / dtms / commitdiff