send_hid/main.c

   1 /*
   2 (C) 2016 Tobias Girstmair, released under the GNU GPL
   3
   4 description: sends a sequence of keystrokes provided from stdin to the hid
   5 device.
   6 stops typing at: control characters (including newline), chars not in table, EOF
   7 parameters:
   8         device file (e.g. /dev/hidg0)
   9         keyboard layout (1=en_us, 2=de_at, 3=de_at-nodeadkeys)
  10         unicode method: 1=gtk_holddown, 2=gtk_spaceend, 3=windows
  11 */
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include "scancodes.h"
  16
  17 #define TEXT_LEN 256 //max length of piped text
  18 enum params {//argv-indices:
  19         P_EXE, //executable name
  20         P_DEV, //device file
  21         P_LAY, //layout
  22         P_UNI, //unicode method
  23         NUM_P  //number of parameters
  24 };
  25 enum uni_m {//unicode methods:
  26         SKIP, //ignore any keys not on the layout
  27         GTK_HOLD, //hold ctrl and shift while entering hex values
  28         GTK_SPACE, //end hex sequence with spacebar
  29         WINDOWS //use alt+numpad
  30 };
  31 enum errors {
  32         ERR_SUCCESS, //no error
  33         ERR_ARGCOUNT, //wrong number of arguments
  34         ERR_SYMBOL, //symbol not in look up table
  35         ERR_LAYOUT, //parameter P_LAY does not contain a correct keyboard layout
  36         ERR_LAZY //i haven't done this
  37 };
  38
  39 void send_key (FILE* hid_dev, unsigned short key, unsigned short mod);
  40 enum errors send_unicode (FILE* hid_dev, unsigned int unicode, enum uni_m method, enum kbdl layout);
  41
  42 int main (int argc, char** argv) {
  43         if (argc != NUM_P) {
  44                 fprintf (stderr, "Usage: %s <device file> <layout> <unicode>\n", argv[P_EXE]);
  45                 fprintf (stderr, "Takes string to type from stdin\n");
  46                 fprintf (stderr, "<device file>:\ton the Raspberry Pi usually /dev/hidg0\n");
  47                 fprintf (stderr, "<layout>:\n\t%d\t%s\n\t%d\t%s\n\t%d\t%s\n",
  48                         en_US, "en_US",
  49                         de_AT, "de_AT (w/ dead keys)",
  50                         de_ND, "de_AT-nodeadkeys");
  51                 fprintf (stderr, "<unicode>:\n\t%d\t%s\n\t%d\t%s\n\t%d\t%s\n\t%d\t%s\n",
  52                         SKIP, "skip over unicode characters",
  53                         GTK_HOLD, "X11 Holddown: CTRL+SHIFT+[u, hex]",
  54                         GTK_SPACE, "X11 Space: CTRL+SHIFT+u, hex, SPACE",
  55                         WINDOWS, "Windows: Alt+[Numpad]");
  56                 return ERR_ARGCOUNT;
  57         }
  58         FILE* hid_dev = fopen (argv[P_DEV], "w");
  59         char in_string[TEXT_LEN];
  60         fgets(in_string, TEXT_LEN, stdin);
  61         for (int i = 0; i < strlen (in_string); i++) {
  62 /*              if (in_string[i] < 32) {
  63                         if (in_string[i] != '\n') fprintf (stderr, "Cannot print control characters!\n(Is there a newline at the end of your string?\n");
  64                         return ERR_SYMBOL;
  65                 }
  66 */
  67                 char tmp[UTF8_MAX_LENGTH] = {in_string[i], in_string[i+1], in_string[i+2], '\0'};
  68                 //TODO: replace by something less stupid
  69                 if (in_string[i] < 128) { // not multi byte
  70                         tmp[1] = '\0';
  71                 } else { // is multi byte
  72                         if (in_string[i] < 0xe0) {
  73                         i++; //skip next thing
  74                         tmp[2] = 0;
  75                         } else {
  76                         i+=2; //WARN: fails on utf8 > 3 byte
  77                         }
  78                 }
  79
  80                 struct keysym* s = toscan (tmp);
  81                 if (s == NULL) {
  82                         fprintf (stderr, "Key Symbol not found.\n");
  83 fclose (hid_dev);
  84                         return ERR_SYMBOL;
  85                 }
  86                 struct layout* l = tolay (s, atoi (argv[P_LAY]));
  87                 if (l == NULL) {
  88                         fprintf (stderr, "Unrecognised keyboard layout.\n");
  89 fclose (hid_dev);
  90                         return ERR_LAYOUT;
  91                 }
  92                 if (l->key != 0x00) {
  93                         send_key(hid_dev, l->key, l->mod);
  94                         send_key(hid_dev, '\0', '\0'); //release all keys
  95                         if (l->is_dead) {
  96                                 //dead keys need to be pressed twice to show up
  97                                 send_key(hid_dev, l->key, l->mod);
  98                                 send_key(hid_dev, '\0', '\0'); //release all keys
  99                         }
 100                 } else {
 101                         //key does not exist in this layout, use unicode method
 102                         //fprintf (stderr, "Warning: Key '%s'(0x%x) not in this layout!\n", s->sym, s->unicode);
 103                         send_unicode (hid_dev, s->unicode, atoi (argv[P_UNI]), atoi(argv[P_LAY]));
 104                 }
 105         }
 106         fclose (hid_dev);
 107
 108         return ERR_SUCCESS;
 109 }
 110
 111 void send_key (FILE* hid_dev, unsigned short key, unsigned short mod) {
 112         fprintf (hid_dev, "%c%c%c%c%c%c%c%c", mod, '\0', key, '\0', '\0', '\0', '\0', '\0');
 113 }
 114
 115 enum errors send_unicode (FILE* hid_dev, unsigned int unicode, enum uni_m method, enum kbdl layout) {
 116         char buf[10];
 117         struct keysym* s;
 118         struct layout* l;
 119
 120         if (unicode == 0x00) {
 121                 fprintf (stderr, "Symbol not in lookup table!\n");
 122                 return ERR_SYMBOL;
 123         }
 124
 125         switch (method) {
 126         case SKIP:
 127                 break;
 128         case GTK_HOLD:
 129                 sprintf (buf, "%x", unicode);
 130                 s = toscan ("u");
 131                 l = tolay (s, layout);
 132                 send_key (hid_dev, l->key, MOD_LCTRL | MOD_LSHIFT);
 133                 for (int i = 0; i < strlen (buf); i++) {
 134                         s = toscan ((char[2]){buf[i], '\0'});
 135                         l = tolay (s, layout);
 136                         send_key (hid_dev, l->key, MOD_LCTRL | MOD_LSHIFT);
 137                 }
 138                 send_key (hid_dev, '\0', '\0');
 139                 break;
 140         case GTK_SPACE:
 141                 sprintf (buf, "%x ", unicode);
 142                 s = toscan ("u");
 143                 l = tolay (s, layout);
 144                 send_key (hid_dev, l->key, MOD_LCTRL | MOD_LSHIFT);
 145                 for (int i = 0; i < strlen (buf); i++) {
 146                         s = toscan ((char[2]){buf[i], '\0'});
 147                         l = tolay (s, layout);
 148                         send_key (hid_dev, l->key, MOD_NONE);
 149                 }
 150                 send_key (hid_dev, '\0', '\0');
 151                 break;
 152         case WINDOWS:
 153                 fprintf (stderr, "windows method not implemented!\n");
 154                 return ERR_LAZY;
 155         default:
 156                 fprintf (stderr, "unknown unicode method!\n");
 157                 return ERR_LAYOUT; //TODO: better error code
 158         }
 159         return ERR_SUCCESS;
 160 }