Accept short options

[keystroke-timestamps] / keystroke-timestamps.c

diff --git a/keystroke-timestamps.c b/keystroke-timestamps.c
index d7aeaf660ff4f8450310435aeb1e8a47ed0178d5..e0433bfa6668041b6167ec24b6caceced3927ab1 100644 (file)
--- a/keystroke-timestamps.c
+++ b/keystroke-timestamps.c
@@ -9,25 +9,49 @@
 #include <sys/select.h>
 #include <unistd.h>
 
+// This constant is defined in include/uapi/linux/input-event-codes.h
+#ifndef EV_KEY
+#define EV_KEY      0x01
+#endif
+
+
 int main (int argc, char **argv)
 {
   int print_usec = 0;
   char* device = "/dev/input/by-path/*kbd*";
+  char* output = NULL;
   struct option long_options[] = {
     {"device", required_argument, 0,            'd' },
+    {"output", required_argument, 0,            'o' },
     {"usec",   no_argument,       &print_usec,  1   },
     {0,        0,                 0,            0   },
   };
   while (1) {
-    int c = getopt_long(argc, argv, "", long_options, NULL);
+    int c = getopt_long(argc, argv, "d:o:", long_options, NULL);
     if (c == -1) break;
     if (c == 'd') {
       device = optarg;
       continue;
     }
+    if (c == 'o') {
+      output = optarg;
+      continue;
+    }
     if (c != 0) exit(EX_USAGE);
   }
 
+  /* Open output file */
+  FILE *output_file;
+  if (output == NULL) {
+    output_file = stdout;
+  } else {
+    output_file = fopen(output, "a");
+    if (output_file == NULL) {
+      err(EX_CANTCREAT, "Could not open output file: %s", output);
+    }
+  }
+
+  /* Open device inputs */
   fd_set all_inputs;
   FD_ZERO(&all_inputs);
   int maxfd = 0;
@@ -51,10 +75,11 @@ int main (int argc, char **argv)
   }
   globfree(&glob_result);
 
+  /* Report keystroke timestamps */
   struct input_event i;
   while (1) {
     fd_set ready_inputs = all_inputs;
-    if (select(maxfd+1, &ready_inputs, NULL, NULL, NULL) != 1) {
+    if (select(maxfd+1, &ready_inputs, NULL, NULL, NULL) < 1) {
       err(EX_IOERR, "select");
     }
     for (int fd=0; fd <= maxfd; fd++) {
@@ -66,13 +91,13 @@ int main (int argc, char **argv)
         if (read_return != sizeof(i)) {
           errx(EX_IOERR, "Unexpected EOF");
         }
-        if (i.type == 1 && i.value == 1) {
+        if (i.type == EV_KEY && i.value == 1) {
           if (print_usec) {
-            printf("%ld.%06ld\n", i.time.tv_sec, i.time.tv_usec);
+            fprintf(output_file, "%ld.%06ld\n", i.time.tv_sec, i.time.tv_usec);
           } else {
-            printf("%ld\n", i.time.tv_sec);
+            fprintf(output_file, "%ld\n", i.time.tv_sec);
           }
-          fflush(stdout);
+          fflush(output_file);
         }
       }
     }