files/x11cursorvis.c

   1 /*
   2  * code protected with a GNU affero GPLv3 license
   3  * copyright (C) 2020 Sylvain BERTRAND
   4  */
   5 /*
   6  * usage:
   7  * "x11cursorvis" alone will turn _ON_ the cursor visibility for the lifetime
   8  * of the client
   9  * "x11cursorvis WHATEVER" will turn _OFF_ x11 the cursor visibility for the
  10  * lifetime of the client
  11  *
  12  * XXX: this code is there for cut and paste as the visibility will be reset
  13  * once the client is gone
  14  */
  15 #include <stdbool.h>
  16 #include <stdlib.h>
  17 #include <stdio.h>
  18 #include <stdint.h>
  19 #include <errno.h>
  20 #include <string.h>
  21 #include <unistd.h>
  22 #include <sys/socket.h>
  23 #include <sys/un.h>
  24 /*
  25  * ABBREVIATIONS:
  26  * addr : ADDRess
  27  * auth : AUTHentication
  28  * err(s) : ERRor(S)
  29  * evt(s) : EVenT(S)
  30  * fd : File Descriptor
  31  * fmt(s) : ForMaT(S)
  32  * img(s) : IMaGe(S)
  33  * max : MAXimum
  34  * min : MINimum
  35  * n : couNt
  36  * nr(s) : NumbeR(S)
  37  * of : OFfset
  38  * recv : RECeiVe
  39  * rep(s) : REPly(ieS)
  40  * req(s) : REQuest(S)
  41  * scr(s) : SCReen(S)
  42  * seq : SEQuence
  43  * str(s) : STRing(S)
  44  * so : SOcket
  45  * sz : SiZe (usually a count of bytes)
  46  * w(s) : Word(S) (32 bits)
  47  * win(s) : WINdow(S)
  48  */
  49 #define u8 uint8_t
  50 #define u16 uint16_t
  51 #define u32 uint32_t
  52 #define loop for(;;)
  53 #define FATAL(fmt, ...) ({fprintf(stderr, fmt, ##__VA_ARGS__); exit(EXIT_FAILURE);})
  54 #define POUT(fmt, ...) fprintf(stdout, fmt, ##__VA_ARGS__)
  55 #define PERR(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)
  56 static u8 *so_pathname = "/tmp/.X11-unix/X0";
  57 static int so_fd;
  58 #ifdef __GNUC__
  59 #define PACKED __attribute__((packed))
  60 #else
  61         #error "missing C extension for packed structure declaration"
  62 #endif
  63 struct x11_setup {
  64         u8 endian;
  65         u8 unused0;
  66         u16 major;
  67         u16 minor;
  68         u16 auth_name_sz;
  69         u16 auth_data_sz;
  70         u16 unused1;
  71 } PACKED;
  72 struct x11_setup_status_common {
  73         u8 code;
  74         u8 unused_or_reason_sz;
  75         u16 major;
  76         u16 minor;
  77         u16 additional_data_ws_n;
  78 } PACKED;
  79 struct x11_query_extension_req {
  80         u8 opcode;
  81         u8 unused0;
  82         u16 req_ws_n;
  83         /*--------------------------------------------------------------------*/
  84         u16 name_bytes_n;
  85         u16 unused1;
  86         u8 name[];
  87 } PACKED;
  88 struct x11_query_extension_rep {
  89         u8 code;
  90         u8 unused0;
  91         u16 seq_nr;
  92         u32 rep_ws_n;
  93         /*--------------------------------------------------------------------*/
  94         u8 present;
  95         u8 opcode_major;
  96         u8 first_evt;
  97         u8 first_err;
  98         u8 unused1[20];
  99 } PACKED;
 100 struct x11_xfixes_query_version_req {
 101         u8 opcode_major;
 102         u8 opcode_minor;
 103         u16 req_ws_n;
 104         /*--------------------------------------------------------------------*/
 105         u32 version_major;
 106         u32 version_minor;
 107 } PACKED;
 108 struct x11_xfixes_query_version_rep {
 109         u8 code;
 110         u8 unused0;
 111         u16 seq_nr;
 112         u32 rep_ws_n;
 113         /*--------------------------------------------------------------------*/
 114         u32 version_major;
 115         u32 version_minor;
 116         u32 unused1[4];
 117 } PACKED;
 118 struct x11_xfixes_hide_or_show_cursor_req {
 119         u8 opcode_major;
 120         u8 opcode_minor;
 121         u16 req_ws_n;
 122         /*--------------------------------------------------------------------*/
 123         u32 win_id;
 124 } PACKED;
 125 /* handle short write */
 126 static void x11_write(void *data, u16 sz)
 127 {
 128         u8 *p;
 129         size_t sent_bytes_n;
 130
 131         if (sz == 0)
 132                 return;
 133         sent_bytes_n = 0;
 134         p = data;
 135         loop {
 136                 ssize_t r;
 137
 138                 errno = 0;
 139                 r = write(so_fd, p, (size_t)sz - sent_bytes_n);
 140                 if (r == -1)
 141                         FATAL("error while sending %u bytes to the x11 server:%s\n", (int)((size_t)sz - sent_bytes_n), strerror(errno));
 142
 143                 sent_bytes_n += (size_t)r;
 144                 if (sent_bytes_n == (size_t)sz)
 145                         break;
 146                 p += r;
 147         }
 148 }
 149 /* handle short read */
 150 static u16 x11_read(void *buf, u16 max_sz)
 151 {
 152         u8 *p;
 153         size_t recv_bytes_n;
 154
 155         if (max_sz == 0)
 156                 return 0;
 157         p = buf;
 158         recv_bytes_n = 0;
 159         loop {
 160                 ssize_t r;
 161
 162                 errno = 0;
 163                 r = read(so_fd, p, (size_t)max_sz - recv_bytes_n);
 164                 if (r == -1)
 165                         FATAL("error while receiving %u bytes from the x11 server:%s\n", (int)((size_t)max_sz - recv_bytes_n), strerror(errno));
 166                 if (r == 0) /* no more data: 0-sized datagram, connection properly closed, end of file... */
 167                         break;
 168                 recv_bytes_n += (size_t)r;
 169                 if (recv_bytes_n == (size_t)max_sz)
 170                         break;
 171                 p += r;
 172         }
 173         return (u16)recv_bytes_n;
 174 }
 175 int main(int argc, u8 **argv)
 176 {
 177         int ri;
 178         u16 r16;
 179         struct sockaddr_un addr;
 180         struct x11_setup x11_setup;
 181         struct x11_setup_status_common x11_status;
 182         u8 *additional_data;
 183         u16 vendor_str_bytes_n;
 184         u8 *vendor_str_bytes_n_of;
 185         u32 vendor_str_pad_bytes_n;
 186         u8 *scrs_n_of;
 187         u8 scrs_n;
 188         u8 *formats_n_of;
 189         u8 formats_n;
 190         //struct format *f;
 191         u8 *scrs_of;
 192         u16 *scr0_width_of;
 193         u16 *scr0_height_of;
 194         u32 rootwin_id;
 195         u16 req_ws_n;
 196         struct x11_query_extension_req *qe_req;
 197         u16 ext_name_pad_bytes_n;
 198         struct x11_query_extension_rep qe_rep;
 199         struct x11_xfixes_query_version_req xf_qv_req;
 200         struct x11_xfixes_query_version_rep xf_qv_rep;
 201         struct x11_xfixes_hide_or_show_cursor_req xf_hos_req;
 202         bool show_cursor;
 203
 204         close(0);
 205         additional_data = 0;
 206
 207         errno = 0;
 208         /* xserver expects a SOCK_STREAM socket */
 209         ri = socket(AF_UNIX, SOCK_STREAM, 0);
 210         if (ri == -1)
 211                 FATAL("unable to create a socket:%s\n", strerror(errno));
 212         so_fd = ri;
 213
 214         memset(&addr, 0, sizeof(addr));
 215         addr.sun_family = AF_UNIX;
 216         strncpy(addr.sun_path, so_pathname, sizeof(addr.sun_path));
 217         ri = connect(so_fd, (struct sockaddr*)&addr, sizeof(addr));
 218         if (ri == -1)
 219                 FATAL("unable to connect the socket %d to address '%s':%s\n", so_fd, so_pathname, strerror(errno));
 220         POUT("connected to unix socket '%s'\n", so_pathname);
 221         /*====================================================================*/
 222         POUT("\nx11 setup -- START\n");
 223         memset(&x11_setup, 0, sizeof(x11_setup));
 224         x11_setup.endian = 'l'; /* l-ittle endian or 'B'-ig endian */
 225         x11_setup.major = 11; /* wayland is x12 */
 226         x11_write(&x11_setup, sizeof(x11_setup));
 227         POUT("x11 connection setup sent\n");
 228         POUT("receiving x11 setup status common data...\n");
 229         r16 = x11_read(&x11_status, sizeof(x11_status));
 230         if (r16 != sizeof(x11_status))
 231                 FATAL("unable to get x11 setup status common data\n");
 232         if (x11_status.additional_data_ws_n != 0) {
 233                 additional_data = realloc(additional_data, x11_status.additional_data_ws_n * 4);
 234                 if (additional_data == 0)
 235                         FATAL("unable to allocate memory to x11 setup status additional data\n");
 236                 POUT("receiving x11 setup status additional data, %u bytes...\n", x11_status.additional_data_ws_n * 4);
 237                 r16 = x11_read(additional_data, x11_status.additional_data_ws_n * 4);
 238                 if (r16 != (x11_status.additional_data_ws_n * 4))
 239                         FATAL("incomplete x11 setup status additional data\n");
 240         }
 241         if (x11_status.code == 0) {
 242                 POUT("x11 setup: failure\n");
 243                 if (x11_status.additional_data_ws_n != 0)
 244                         /* don't expect any string to end with '\0' */
 245                         FATAL("reason:%.*s\n", (int)x11_status.unused_or_reason_sz, additional_data);
 246                 FATAL("no failure reason provided\n");
 247         }
 248         if (x11_status.code == 2)
 249                 FATAL("x11 setup: authentication is not supported\n");
 250         if (x11_status.code != 1)
 251                 FATAL("x11 setup: unknown status code (0x%02x)\n", x11_status.code);
 252         /* x11_status.code == 1 */
 253         POUT("x11 setup success\n");
 254         POUT("x11 setup -- END\n");
 255         /*====================================================================*/
 256         POUT("\nx11 setup additional data processing -- START\n");
 257         #define VENDOR_STR_OF   32
 258         #define FORMAT_BYTES_N  8
 259         vendor_str_bytes_n_of = additional_data + 16; /* x11 specs */
 260         vendor_str_bytes_n = *(u16*)vendor_str_bytes_n_of;
 261         vendor_str_pad_bytes_n = vendor_str_bytes_n % 4 ?
 262                                         4 - (vendor_str_bytes_n % 4) : 0;
 263         POUT("vendor string size=%u bytes/%u padding bytes\n", vendor_str_bytes_n, vendor_str_pad_bytes_n);
 264         /* don't expect any sting to end with '\0' */
 265         POUT("vendor str is \"%.*s\"\n", vendor_str_bytes_n, additional_data + VENDOR_STR_OF);
 266         /*--------------------------------------------------------------------*/
 267         scrs_n_of = additional_data + 20;
 268         scrs_n = *scrs_n_of;
 269         POUT("count of screens is %u\n", scrs_n);
 270         /*--------------------------------------------------------------------*/
 271         formats_n_of = additional_data + 21;
 272         formats_n = *formats_n_of;
 273         POUT("count of formats is %u\n", formats_n);
 274         /*--------------------------------------------------------------------*/
 275         scrs_of = additional_data + VENDOR_STR_OF + vendor_str_bytes_n
 276                         + vendor_str_pad_bytes_n + FORMAT_BYTES_N * formats_n;
 277         rootwin_id = *(u32*)scrs_of;
 278         scr0_width_of = (u16*)(scrs_of + 20);
 279         scr0_height_of = (u16*)(scrs_of + 22);
 280         POUT("screen 0:root window id=0x%08x;width=%u pixels;height=%u pixels\n", rootwin_id, *scr0_width_of, *scr0_height_of);
 281         #undef VENDOR_STR_OF
 282         #undef FORMAT_BYTES_N
 283         POUT("x11 setup additional data processing -- END\n");
 284         /*====================================================================*/
 285         POUT("\nQueryExtension request -- START\n");
 286         #define STR_SZ(x) (sizeof(x)-1) /* terminate the terminating '\0' */
 287         #define EXTENSION_NAME "XFIXES"
 288         ext_name_pad_bytes_n = STR_SZ(EXTENSION_NAME) % 4 ?  4
 289                                         - (STR_SZ(EXTENSION_NAME) % 4) : 0;
 290         req_ws_n = 2 + (STR_SZ(EXTENSION_NAME) + ext_name_pad_bytes_n) / 4;
 291         qe_req = calloc(1, req_ws_n * 4);
 292         qe_req->opcode = 98;
 293         qe_req->req_ws_n = req_ws_n;
 294         qe_req->name_bytes_n = STR_SZ(EXTENSION_NAME);
 295         strncpy(qe_req->name, EXTENSION_NAME, STR_SZ(EXTENSION_NAME));
 296         x11_write(qe_req, req_ws_n * 4);
 297         POUT("QueryExtension request sent\n");
 298         #undef STR_SZ
 299         #undef EXTENSION_NAME
 300         POUT("QueryExtension request -- END\n");
 301         /*====================================================================*/
 302         POUT("\nQueryExtension reply -- START\n");
 303         memset(&qe_rep, 0, sizeof(qe_rep));
 304         r16 = x11_read(&qe_rep, sizeof(qe_rep));
 305         if (r16 != sizeof(qe_rep))
 306                 FATAL("unable to get query extension reply\n");
 307         POUT("\
 308 QueryExtension reply:\n\
 309         code                            = %u\n\
 310         sequence number                 = %u\n\
 311         reply 32bits words count        = %u\n\
 312         present                         = %s\n\
 313         major opcode                    = %u\n\
 314         first event                     = %u\n\
 315         first err                       = %u\n\
 316 ", qe_rep.code, qe_rep.seq_nr, qe_rep.rep_ws_n, qe_rep.present ? "yes" : "no", qe_rep.opcode_major, qe_rep.first_evt, qe_rep.first_err);
 317         POUT("QueryExtension reply -- END\n");
 318         /*====================================================================*/
 319         POUT("\nxfixes QueryVersion request -- START\n");
 320         #define QUERY_VERSION_MINOR 0
 321         #define REQ_WS_N 3
 322         memset(&xf_qv_req, 0, sizeof(xf_qv_req));
 323         xf_qv_req.opcode_major = qe_rep.opcode_major;
 324         xf_qv_req.opcode_minor = QUERY_VERSION_MINOR;
 325         xf_qv_req.req_ws_n = REQ_WS_N;
 326         xf_qv_req.version_major = 4;
 327         xf_qv_req.version_minor = 0;
 328         x11_write(&xf_qv_req, REQ_WS_N * 4);
 329         POUT("xfixes QueryVersion request sent\n");
 330         #undef QUERY_VERSION_MINOR
 331         #undef REQ_WS_N
 332         POUT("xfixes QueryVersion request -- END\n");
 333         /*====================================================================*/
 334         POUT("\nxfixes QueryVersion reply -- START\n");
 335         memset(&xf_qv_rep, 0, sizeof(xf_qv_rep));
 336         r16 = x11_read(&xf_qv_rep, sizeof(xf_qv_rep));
 337         if (r16 != sizeof(xf_qv_rep))
 338                 FATAL("unable to get xfixes query version reply\n");
 339         POUT("\
 340 xfixes QueryVersion reply:\n\
 341         code                            = %u\n\
 342         sequence number                 = %u\n\
 343         reply 32bits words count        = %u\n\
 344         major version                   = %u\n\
 345         minor version                   = %u\n\
 346 ", xf_qv_rep.code, xf_qv_rep.seq_nr, xf_qv_rep.rep_ws_n, xf_qv_rep.version_major, xf_qv_rep.version_minor);
 347         POUT("xfixes QueryVersion reply -- END\n");
 348         /*====================================================================*/
 349         POUT("\nxfixes [Hide/Show]Cursor request -- START\n");
 350         #define XFIXES_HIDE_CURSOR 29
 351         #define XFIXES_SHOW_CURSOR 30
 352         #define REQ_WS_N 2
 353         memset(&xf_hos_req, 0, sizeof(xf_hos_req));
 354         xf_hos_req.opcode_major = qe_rep.opcode_major;
 355         if (argc > 1) {
 356                 show_cursor = false;
 357                 xf_hos_req.opcode_minor = XFIXES_HIDE_CURSOR;
 358         } else {
 359                 show_cursor = true;
 360                 xf_hos_req.opcode_minor = XFIXES_SHOW_CURSOR;
 361         }
 362         xf_hos_req.req_ws_n = REQ_WS_N;
 363         xf_hos_req.win_id = rootwin_id;
 364         x11_write(&xf_hos_req, REQ_WS_N * 4);
 365         POUT("xfixes %sCursor request sent on the root window (id = 0x%08x)\n", show_cursor ? "Show" : "Hide", rootwin_id);
 366         #undef XFIXES_HIDE_CURSOR
 367         #undef XFIXES_SHOW_CURSOR
 368         #undef REQ_WS_N
 369         POUT("xfixes [Hide/Show]Cursor request -- END\n");
 370         /*====================================================================*/
 371         POUT("done\n");
 372         sleep(10);
 373         exit(EXIT_SUCCESS);
 374 }