git.scottworley.com Git - keystroke-timestamps/blob - keystroke-timestamps.c

   1 #include <err.h>
   2 #include <fcntl.h>
   3 #include <glob.h>
   4 #include <getopt.h>
   5 #include <linux/input.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <sysexits.h>
   9 #include <sys/select.h>
  10 #include <unistd.h>
  11
  12 // This constant is defined in include/uapi/linux/input-event-codes.h
  13 #ifndef EV_KEY
  14 #define EV_KEY      0x01
  15 #endif
  16
  17
  18 int main (int argc, char **argv)
  19 {
  20   int print_usec = 0;
  21   char* device = "/dev/input/by-path/*kbd*";
  22   char* output = NULL;
  23   struct option long_options[] = {
  24     {"device", required_argument, 0,            'd' },
  25     {"output", required_argument, 0,            'o' },
  26     {"usec",   no_argument,       &print_usec,  1   },
  27     {0,        0,                 0,            0   },
  28   };
  29   while (1) {
  30     int c = getopt_long(argc, argv, "", long_options, NULL);
  31     if (c == -1) break;
  32     if (c == 'd') {
  33       device = optarg;
  34       continue;
  35     }
  36     if (c == 'o') {
  37       output = optarg;
  38       continue;
  39     }
  40     if (c != 0) exit(EX_USAGE);
  41   }
  42
  43   /* Open output file */
  44   FILE *output_file;
  45   if (output == NULL) {
  46     output_file = stdout;
  47   } else {
  48     output_file = fopen(output, "a");
  49     if (output_file == NULL) {
  50       err(EX_CANTCREAT, "Could not open output file: %s", output);
  51     }
  52   }
  53
  54   /* Open device inputs */
  55   fd_set all_inputs;
  56   FD_ZERO(&all_inputs);
  57   int maxfd = 0;
  58   glob_t glob_result;
  59   int glob_return = glob(device, GLOB_ERR | GLOB_NOSORT, NULL, &glob_result);
  60   if (glob_return == GLOB_NOMATCH) {
  61     errx(EX_NOINPUT, "Could not find keyboard event file(s): %s", device);
  62   }
  63   if (glob_return != 0) {
  64     err(EX_NOINPUT, "Could not glob keyboard event file(s): %s", device);
  65   }
  66   for (unsigned i = 0; i < glob_result.gl_pathc; i++) {
  67     int device_fd = open(glob_result.gl_pathv[i], O_RDONLY);
  68     if (device_fd < 0) {
  69       err(EX_NOINPUT, "Could not open keyboard event file: %s", glob_result.gl_pathv[i]);
  70     }
  71     if (device_fd > maxfd) {
  72       maxfd = device_fd;
  73     }
  74     FD_SET(device_fd, &all_inputs);
  75   }
  76   globfree(&glob_result);
  77
  78   /* Report keystroke timestamps */
  79   struct input_event i;
  80   while (1) {
  81     fd_set ready_inputs = all_inputs;
  82     if (select(maxfd+1, &ready_inputs, NULL, NULL, NULL) != 1) {
  83       err(EX_IOERR, "select");
  84     }
  85     for (int fd=0; fd <= maxfd; fd++) {
  86       if (FD_ISSET(fd, &ready_inputs)) {
  87         int read_return = read(fd, &i, sizeof(i));
  88         if (read_return == -1) {
  89           err(EX_IOERR, "read");
  90         }
  91         if (read_return != sizeof(i)) {
  92           errx(EX_IOERR, "Unexpected EOF");
  93         }
  94         if (i.type == EV_KEY && i.value == 1) {
  95           if (print_usec) {
  96             fprintf(output_file, "%ld.%06ld\n", i.time.tv_sec, i.time.tv_usec);
  97           } else {
  98             fprintf(output_file, "%ld\n", i.time.tv_sec);
  99           }
 100           fflush(output_file);
 101         }
 102       }
 103     }
 104   }
 105   return 0;
 106 }