files/x11keyautorepeat.c

   1 /*
   2  * code protected with a GNU affero GPLv3 license
   3  * copyright (C) 2020 Sylvain BERTRAND
   4  */
   5 /*
   6  * usage:
   7  * "x11keyautorepeat" alone will turn off x11 global key repeat
   8  * "x11keyautorepeat WHATEVER" will turn on x11 global key repeat
   9  */
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <stdint.h>
  13 #include <errno.h>
  14 #include <string.h>
  15
  16 #include <unistd.h>
  17 #include <sys/socket.h>
  18 #include <sys/un.h>
  19 /*
  20  * ABBREVIATIONS:
  21  * addr : ADDRess
  22  * auth : AUTHentication
  23  * fd : File Descriptor
  24  * fmt(s) : ForMaT(S)
  25  * img(s) : IMaGe(S)
  26  * max : MAXimum
  27  * min : MINimum
  28  * n : couNt
  29  * num(S) : NUMber(S)
  30  * recv : RECeiVe
  31  * req(s) : REQuest(S)
  32  * scr(s) : SCReen(S)
  33  * so : SOcket
  34  * sz : SiZe (usually a count of bytes)
  35  * w(s) : Word(S) (32 bits)
  36  */
  37 #define u8 uint8_t
  38 #define u16 uint16_t
  39 #define u32 uint32_t
  40 #define loop for(;;)
  41 #define FATAL(fmt, ...) ({fprintf(stderr, fmt, ##__VA_ARGS__); exit(EXIT_FAILURE);})
  42 #define POUT(fmt, ...) fprintf(stdout, fmt, ##__VA_ARGS__)
  43 #define PERR(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)
  44
  45 static u8 *so_pathname = "/tmp/.X11-unix/X0";
  46 static int so_fd;
  47
  48 #ifdef __GNUC__
  49 #define PACKED __attribute__((packed))
  50 #else
  51         #error "missing C extension for packed structure declaration"
  52 #endif
  53 struct x11_setup {
  54         u8 endian;
  55         u8 unused0;
  56         u16 major;
  57         u16 minor;
  58         u16 auth_name_sz;
  59         u16 auth_data_sz;
  60         u16 unused1;
  61 } PACKED;
  62
  63 struct x11_setup_status_common {
  64         u8 code;
  65         u8 unused_or_reason_sz;
  66         u16 major;
  67         u16 minor;
  68         u16 additional_data_ws_n;
  69 } PACKED;
  70
  71 struct x11_change_keyboard_control_req {
  72         u8 opcode;
  73         u8 unused;
  74         u16 req_ws_n;
  75         u32 mask;
  76         u8 auto_repeat_mode;
  77         u8 pad[3];
  78 } PACKED;
  79 /* handle short write */
  80 static void x11_write(void *data, u16 sz)
  81 {
  82         u8 *p;
  83         size_t sent_bytes_n;
  84
  85         if (sz == 0)
  86                 return;
  87         sent_bytes_n = 0;
  88         p = data;
  89         loop {
  90                 ssize_t r;
  91
  92                 errno = 0;
  93                 r = write(so_fd, p, (size_t)sz - sent_bytes_n);
  94                 if (r == -1)
  95                         FATAL("error while sending %u bytes to the x11 server:%s\n", (int)((size_t)sz - sent_bytes_n), strerror(errno));
  96
  97                 sent_bytes_n += (size_t)r;
  98                 if (sent_bytes_n == (size_t)sz)
  99                         break;
 100                 p += r;
 101         }
 102 }
 103 /* handle short read */
 104 static u16 x11_read(void *buf, u16 max_sz)
 105 {
 106         u8 *p;
 107         size_t recv_bytes_n;
 108
 109         if (max_sz == 0)
 110                 return 0;
 111         p = buf;
 112         recv_bytes_n = 0;
 113         loop {
 114                 ssize_t r;
 115
 116                 errno = 0;
 117                 r = read(so_fd, p, (size_t)max_sz - recv_bytes_n);
 118                 if (r == -1)
 119                         FATAL("error while receiving %u bytes from the x11 server:%s\n", (int)((size_t)max_sz - recv_bytes_n), strerror(errno));
 120                 if (r == 0) /* no more data: 0-sized datagram, connection properly closed, end of file... */
 121                         break;
 122                 recv_bytes_n += (size_t)r;
 123                 if (recv_bytes_n == (size_t)max_sz)
 124                         break;
 125                 p += r;
 126         }
 127         return (u16)recv_bytes_n;
 128 }
 129
 130 int main(int argc, u8 **argv)
 131 {
 132         int ri;
 133         u16 r16;
 134         struct sockaddr_un addr;
 135         struct x11_setup x11_setup;
 136         struct x11_setup_status_common x11_status;
 137         u8 *additional_data;
 138         struct x11_change_keyboard_control_req req;
 139
 140         close(0);
 141         additional_data = 0;
 142
 143         errno = 0;
 144         /* xserver expects a SOCK_STREAM socket */
 145         ri = socket(AF_UNIX, SOCK_STREAM, 0);
 146         if (ri == -1)
 147                 FATAL("unable to create a socket:%s\n", strerror(errno));
 148         so_fd = ri;
 149
 150         memset(&addr, 0, sizeof(addr));
 151         addr.sun_family = AF_UNIX;
 152         strncpy(addr.sun_path, so_pathname, sizeof(addr.sun_path));
 153         ri = connect(so_fd, (struct sockaddr*)&addr, sizeof(addr));
 154         if (ri == -1)
 155                 FATAL("unable to connect the socket %d to address '%s':%s\n", so_fd, so_pathname, strerror(errno));
 156         POUT("connected to unix socket '%s'\n", so_pathname);
 157         /*--------------------------------------------------------------------*/
 158         /*  x11 setup */
 159         memset(&x11_setup, 0, sizeof(x11_setup));
 160         x11_setup.endian = 'l'; /* l-ittle endian or 'B'-ig endian */
 161         x11_setup.major = 11; /* wayland is x12 */
 162
 163         x11_write(&x11_setup, sizeof(x11_setup));
 164         POUT("x11 connection setup sent\n");
 165
 166         POUT("receiving x11 setup status common data...\n");
 167         r16 = x11_read(&x11_status, sizeof(x11_status));
 168         if (r16 != sizeof(x11_status))
 169                 FATAL("unable to get x11 setup status common data\n");
 170         if (x11_status.additional_data_ws_n != 0) {
 171                 additional_data = realloc(additional_data, x11_status.additional_data_ws_n * 4);
 172                 if (additional_data == 0)
 173                         FATAL("unable to allocate memory to x11 setup status additional data\n");
 174                 POUT("receiving x11 setup status additional data, %u bytes...\n", x11_status.additional_data_ws_n * 4);
 175                 r16 = x11_read(additional_data, x11_status.additional_data_ws_n * 4);
 176                 if (r16 != (x11_status.additional_data_ws_n * 4))
 177                         FATAL("incomplete x11 setup status additional data\n");
 178         }
 179
 180         if (x11_status.code == 0) {
 181                 POUT("x11 setup: failure\n");
 182                 if (x11_status.additional_data_ws_n != 0)
 183                         /* don't expect any string to end with '\0' */
 184                         FATAL("reason:%.*s\n", (int)x11_status.unused_or_reason_sz, additional_data);
 185                 FATAL("no failure reason provided\n");
 186         }
 187
 188         free(additional_data);
 189         additional_data = 0;
 190
 191         if (x11_status.code == 2)
 192                 FATAL("x11 setup: authentication is not supported\n");
 193         if (x11_status.code != 1)
 194                 FATAL("x11 setup: unknown status code (0x%02x)\n", x11_status.code);
 195         /* x11_status.code == 1 */
 196         POUT("x11 setup success\n");
 197         /*--------------------------------------------------------------------*/
 198         /* change_keyboard_control req */
 199         memset(&req, 0, sizeof(req));
 200         req.opcode = 102;
 201         req.req_ws_n = sizeof(req) / 4;
 202         req.mask = 0x80; /* auto-repeat-mode */
 203         if (argc > 1)
 204                 req.auto_repeat_mode = 1; /* 1 = on, 0 = off, 2 = default */
 205         POUT("sending x11 change_keyboard_control request\n");
 206         x11_write(&req, sizeof(req));
 207         POUT("done\n");
 208         exit(EXIT_SUCCESS);
 209 }