fbvnc.c

   1 /*
   2  * FBVNC: a small Linux framebuffer VNC viewer
   3  *
   4  * Copyright (C) 2009-2021 Ali Gholami Rudi
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include <arpa/inet.h>
  19 #include <ctype.h>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <netdb.h>
  23 #include <netinet/in.h>
  24 #include <poll.h>
  25 #include <pwd.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <termios.h>
  30 #include <unistd.h>
  31 #include <sys/socket.h>
  32 #include <sys/stat.h>
  33 #include <sys/types.h>
  34 #include <linux/input.h>
  35 #include "draw.h"
  36 #include "vnc.h"
  37
  38 #define MIN(a, b)       ((a) < (b) ? (a) : (b))
  39 #define MAX(a, b)       ((a) > (b) ? (a) : (b))
  40 #define OUT(msg)        write(1, (msg), strlen(msg))
  41
  42 #define VNC_PORT        "5900"
  43 #define SCRSCRL         2
  44 #define MAXRES          (1 << 16)
  45
  46 static int cols, rows;          /* framebuffer dimensions */
  47 static int bpp;                 /* bytes per pixel */
  48 static int srv_cols, srv_rows;  /* server screen dimensions */
  49 static int or, oc;              /* visible screen offset */
  50 static int mr, mc;              /* mouse position */
  51 static int nodraw;              /* don't draw anything */
  52 static long vnc_nr;             /* number of bytes received */
  53 static long vnc_nw;             /* number of bytes sent */
  54
  55 static char buf[MAXRES];
  56
  57 static int vnc_connect(char *addr, char *port)
  58 {
  59         struct addrinfo hints, *addrinfo;
  60         int fd;
  61
  62         memset(&hints, 0, sizeof(hints));
  63         hints.ai_family = AF_UNSPEC;
  64         hints.ai_socktype = SOCK_STREAM;
  65         hints.ai_flags = AI_PASSIVE;
  66
  67         if (getaddrinfo(addr, port, &hints, &addrinfo))
  68                 return -1;
  69         fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
  70                         addrinfo->ai_protocol);
  71
  72         if (connect(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) == -1) {
  73                 close(fd);
  74                 freeaddrinfo(addrinfo);
  75                 return -1;
  76         }
  77         freeaddrinfo(addrinfo);
  78         return fd;
  79 }
  80
  81 static void fbmode_bits(int *rr, int *rg, int *rb)
  82 {
  83         int mode = FBM_COLORS(fb_mode());
  84         *rr = (mode >> 8) & 0xf;
  85         *rg = (mode >> 4) & 0xf;
  86         *rb = (mode >> 0) & 0xf;
  87 }
  88
  89 static int vread(int fd, void *buf, long len)
  90 {
  91         long nr = 0;
  92         long n;
  93         while (nr < len && (n = read(fd, buf + nr, len - nr)) > 0)
  94                 nr += n;
  95         vnc_nr += nr;
  96         if (nr < len)
  97                 printf("fbvnc: partial vnc read!\n");
  98         return nr < len ? -1 : len;
  99 }
 100
 101 static int vwrite(int fd, void *buf, long len)
 102 {
 103         int nw = write(fd, buf, len);
 104         if (nw != len)
 105                 printf("fbvnc: partial vnc write!\n");
 106         vnc_nw += len;
 107         return nw < len ? -1 : nw;
 108 }
 109
 110 static int vnc_init(int fd)
 111 {
 112         char vncver[16];
 113         int rr, rg, rb;
 114         struct vnc_clientinit clientinit;
 115         struct vnc_serverinit serverinit;
 116         struct vnc_setpixelformat pixfmt_cmd;
 117         struct vnc_setencoding enc_cmd;
 118         u32 enc[] = {htonl(VNC_ENC_RAW), htonl(VNC_ENC_RRE)};
 119         int connstat = VNC_CONN_FAILED;
 120
 121         /* handshake */
 122         if (vread(fd, vncver, 12) < 0)
 123                 return -1;
 124         strcpy(vncver, "RFB 003.003\n");
 125         vwrite(fd, vncver, 12);
 126         if (vread(fd, &connstat, sizeof(connstat)) < 0)
 127                 return -1;
 128         if (ntohl(connstat) != VNC_CONN_NOAUTH)
 129                 return -1;
 130         clientinit.shared = 1;
 131         vwrite(fd, &clientinit, sizeof(clientinit));
 132         if (vread(fd, &serverinit, sizeof(serverinit)) < 0)
 133                 return -1;
 134         if (vread(fd, buf, ntohl(serverinit.len)) < 0)
 135                 return -1;
 136         srv_cols = ntohs(serverinit.w);
 137         srv_rows = ntohs(serverinit.h);
 138
 139         /* set up the framebuffer */
 140         if (fb_init())
 141                 return -1;
 142         cols = MIN(srv_cols, fb_cols());
 143         rows = MIN(srv_rows, fb_rows());
 144         bpp = FBM_BPP(fb_mode());
 145         mr = rows / 2;
 146         mc = cols / 2;
 147
 148         /* send framebuffer configuration */
 149         pixfmt_cmd.type = VNC_SETPIXELFORMAT;
 150         pixfmt_cmd.format.bpp = bpp << 3;
 151         pixfmt_cmd.format.depth = bpp << 3;
 152         pixfmt_cmd.format.bigendian = 0;
 153         pixfmt_cmd.format.truecolor = 1;
 154         fbmode_bits(&rr, &rg, &rb);
 155         pixfmt_cmd.format.rmax = htons((1 << rr) - 1);
 156         pixfmt_cmd.format.gmax = htons((1 << rg) - 1);
 157         pixfmt_cmd.format.bmax = htons((1 << rb) - 1);
 158
 159         /* assuming colors packed as RGB; shall handle other cases later */
 160         pixfmt_cmd.format.rshl = rg + rb;
 161         pixfmt_cmd.format.gshl = rb;
 162         pixfmt_cmd.format.bshl = 0;
 163         vwrite(fd, &pixfmt_cmd, sizeof(pixfmt_cmd));
 164
 165         /* send pixel format */
 166         enc_cmd.type = VNC_SETENCODING;
 167         enc_cmd.pad = 0;
 168         enc_cmd.n = htons(2);
 169         vwrite(fd, &enc_cmd, sizeof(enc_cmd));
 170         vwrite(fd, enc, ntohs(enc_cmd.n) * sizeof(enc[0]));
 171         return 0;
 172 }
 173
 174 static int vnc_free(void)
 175 {
 176         fb_free();
 177         return 0;
 178 }
 179
 180 static int vnc_refresh(int fd, int inc)
 181 {
 182         struct vnc_updaterequest fbup_req;
 183         fbup_req.type = VNC_UPDATEREQUEST;
 184         fbup_req.inc = inc;
 185         fbup_req.x = htons(oc);
 186         fbup_req.y = htons(or);
 187         fbup_req.w = htons(cols);
 188         fbup_req.h = htons(rows);
 189         return vwrite(fd, &fbup_req, sizeof(fbup_req)) < 0 ? -1 : 0;
 190 }
 191
 192 static void drawfb(char *s, int x, int y, int w, int h)
 193 {
 194         int sc;         /* screen column offset */
 195         int bc, bw;     /* buffer column offset / row width */
 196         int i;
 197         sc = MAX(0, x - oc);
 198         bc = x > oc ? 0 : oc - x;
 199         bw = x + w < oc + cols ? w - bc : w - bc - (x + w - oc - cols);
 200         for (i = y; i < y + h; i++)
 201                 if (i - or >= 0 && i - or < rows && bw > 0)
 202                         fb_set(i - or, sc, s + ((i - y) * w + bc) * bpp, bw);
 203 }
 204
 205 static void drawrect(char *pixel, int x, int y, int w, int h)
 206 {
 207         int i;
 208         if (x < 0 || x + w >= srv_cols || y < 0 || y + h >= srv_rows)
 209                 return;
 210         for (i = 0; i < w; i++)
 211                 memcpy(buf + i * bpp, pixel, bpp);
 212         for (i = 0; i < h; i++)
 213                 drawfb(buf, x, y + i, w, 1);
 214 }
 215
 216 static int readrect(int fd)
 217 {
 218         struct vnc_rect uprect;
 219         int x, y, w, h;
 220         int i;
 221         if (vread(fd, &uprect, sizeof(uprect)) <  0)
 222                 return -1;
 223         x = ntohs(uprect.x);
 224         y = ntohs(uprect.y);
 225         w = ntohs(uprect.w);
 226         h = ntohs(uprect.h);
 227         if (x < 0 || w < 0 || x + w > srv_cols)
 228                 return -1;
 229         if (y < 0 || h < 0 || y + h > srv_rows)
 230                 return -1;
 231         if (uprect.enc == htonl(VNC_ENC_RAW)) {
 232                 for (i = 0; i < h; i++) {
 233                         if (vread(fd, buf, w * bpp) < 0)
 234                                 return -1;
 235                         if (!nodraw)
 236                                 drawfb(buf, x, y + i, w, 1);
 237                 }
 238         }
 239         if (uprect.enc == htonl(VNC_ENC_RRE)) {
 240                 char pixel[8];
 241                 u32 n;
 242                 vread(fd, &n, 4);
 243                 vread(fd, pixel, bpp);
 244                 if (!nodraw)
 245                         drawrect(pixel, x, y, w, h);
 246                 for (i = 0; i < ntohl(n); i++) {
 247                         u16 pos[4];
 248                         vread(fd, pixel, bpp);
 249                         vread(fd, pos, 8);
 250                         if (!nodraw)
 251                                 drawrect(pixel, x + ntohs(pos[0]), y + ntohs(pos[1]),
 252                                         ntohs(pos[2]), ntohs(pos[3]));
 253                 }
 254         }
 255         return 0;
 256 }
 257
 258 static int vnc_event(int fd)
 259 {
 260         char msg[1 << 12];
 261         struct vnc_update *fbup = (void *) msg;
 262         struct vnc_servercuttext *cuttext = (void *) msg;
 263         struct vnc_setcolormapentries *colormap = (void *) msg;
 264         int i;
 265         int n;
 266
 267         if (vread(fd, msg, 1) < 0)
 268                 return -1;
 269         switch (msg[0]) {
 270         case VNC_UPDATE:
 271                 vread(fd, msg + 1, sizeof(*fbup) - 1);
 272                 n = ntohs(fbup->n);
 273                 for (i = 0; i < n; i++)
 274                         if (readrect(fd))
 275                                 return -1;
 276                 break;
 277         case VNC_BELL:
 278                 break;
 279         case VNC_SERVERCUTTEXT:
 280                 vread(fd, msg + 1, sizeof(*cuttext) - 1);
 281                 vread(fd, buf, ntohl(cuttext->len));
 282                 break;
 283         case VNC_SETCOLORMAPENTRIES:
 284                 vread(fd, msg + 1, sizeof(*colormap) - 1);
 285                 vread(fd, buf, ntohs(colormap->n) * 3 * 2);
 286                 break;
 287         default:
 288                 fprintf(stderr, "fbvnc: unknown vnc msg %d\n", msg[0]);
 289                 return -1;
 290         }
 291         return 0;
 292 }
 293
 294 static int rat_event(int fd, int ratfd)
 295 {
 296         char ie[4] = {0};
 297         struct vnc_pointerevent me = {VNC_POINTEREVENT};
 298         int mask = 0;
 299         int or_ = or, oc_ = oc;
 300         if (ratfd > 0 && read(ratfd, &ie, sizeof(ie)) != 4)
 301                 return -1;
 302         /* ignore mouse movements when nodraw */
 303         if (nodraw)
 304                 return 0;
 305         mc += ie[1];
 306         mr -= ie[2];
 307
 308         if (mc < oc)
 309                 oc = MAX(0, oc - cols / SCRSCRL);
 310         if (mc >= oc + cols && oc + cols < srv_cols)
 311                 oc = MIN(srv_cols - cols, oc + cols / SCRSCRL);
 312         if (mr < or)
 313                 or = MAX(0, or - rows / SCRSCRL);
 314         if (mr >= or + rows && or + rows < srv_rows)
 315                 or = MIN(srv_rows - rows, or + rows / SCRSCRL);
 316         mc = MAX(oc, MIN(oc + cols - 1, mc));
 317         mr = MAX(or, MIN(or + rows - 1, mr));
 318         if (ie[0] & 0x01)
 319                 mask |= VNC_BUTTON1_MASK;
 320         if (ie[0] & 0x04)
 321                 mask |= VNC_BUTTON2_MASK;
 322         if (ie[0] & 0x02)
 323                 mask |= VNC_BUTTON3_MASK;
 324         if (ie[3] > 0)          /* wheel up */
 325                 mask |= VNC_BUTTON4_MASK;
 326         if (ie[3] < 0)          /* wheel down */
 327                 mask |= VNC_BUTTON5_MASK;
 328
 329         me.y = htons(mr);
 330         me.x = htons(mc);
 331         me.mask = mask;
 332         vwrite(fd, &me, sizeof(me));
 333         if (or != or_ || oc != oc_)
 334                 if (vnc_refresh(fd, 0))
 335                         return -1;
 336         return 0;
 337 }
 338
 339 static int press(int fd, int key, int down)
 340 {
 341         struct vnc_keyevent ke = {VNC_KEYEVENT};
 342         ke.key = htonl(key);
 343         ke.down = down;
 344         vwrite(fd, &ke, sizeof(ke));
 345         return 0;
 346 }
 347
 348 static void showmsg(void)
 349 {
 350         char msg[128];
 351         sprintf(msg, "\x1b[HFBVNC \t\t nr=%-8ld\tnw=%-8ld\r", vnc_nr, vnc_nw);
 352         OUT(msg);
 353 }
 354
 355 static int kbd_event(int fd, int kbdfd)
 356 {
 357         char key[1024];
 358         int i, nr;
 359
 360         if ((nr = read(kbdfd, key, sizeof(key))) <= 0 )
 361                 return -1;
 362         for (i = 0; i < nr; i++) {
 363                 int k = -1;
 364                 int mod[4];
 365                 int nmod = 0;
 366                 switch (key[i]) {
 367                 case 0x08:
 368                 case 0x7f:
 369                         k = 0xff08;
 370                         break;
 371                 case 0x09:
 372                         k = 0xff09;
 373                         break;
 374                 case 0x1b:
 375                         if (i + 2 < nr && key[i + 1] == '[') {
 376                                 if (key[i + 2] == 'A')
 377                                         k = 0xff52;
 378                                 if (key[i + 2] == 'B')
 379                                         k = 0xff54;
 380                                 if (key[i + 2] == 'C')
 381                                         k = 0xff53;
 382                                 if (key[i + 2] == 'D')
 383                                         k = 0xff51;
 384                                 if (key[i + 2] == 'H')
 385                                         k = 0xff50;
 386                                 if (k > 0) {
 387                                         i += 2;
 388                                         break;
 389                                 }
 390                         }
 391                         k = 0xff1b;
 392                         if (i + 1 < nr) {
 393                                 mod[nmod++] = 0xffe9;
 394                                 k = key[++i];
 395                                 if (k == 0x03)  /* esc-^C: quit */
 396                                         return -1;
 397                         }
 398                         break;
 399                 case 0x0d:
 400                         k = 0xff0d;
 401                         break;
 402                 case 0x0:       /* c-space: stop/start drawing */
 403                         if (!nodraw) {
 404                                 nodraw = 1;
 405                                 showmsg();
 406                         } else {
 407                                 nodraw = 0;
 408                                 if (vnc_refresh(fd, 0))
 409                                         return -1;
 410                         }
 411                 default:
 412                         k = (unsigned char) key[i];
 413                 }
 414                 if ((k >= 'A' && k <= 'Z') || strchr(":\"<>?{}|+_()*&^%$#@!~", k))
 415                         mod[nmod++] = 0xffe1;
 416                 if (k >= 1 && k <= 26) {
 417                         k = 'a' + k - 1;
 418                         mod[nmod++] = 0xffe3;
 419                 }
 420                 if (k > 0) {
 421                         int j;
 422                         for (j = 0; j < nmod; j++)
 423                                 press(fd, mod[j], 1);
 424                         press(fd, k, 1);
 425                         press(fd, k, 0);
 426                         for (j = 0; j < nmod; j++)
 427                                 press(fd, mod[j], 0);
 428                 }
 429         }
 430         return 0;
 431 }
 432
 433 static void term_setup(struct termios *ti)
 434 {
 435         struct termios termios;
 436         OUT("\033[2J");         /* clear the screen */
 437         OUT("\033[?25l");       /* hide the cursor */
 438         showmsg();
 439         tcgetattr(0, &termios);
 440         *ti = termios;
 441         cfmakeraw(&termios);
 442         tcsetattr(0, TCSANOW, &termios);
 443 }
 444
 445 static void term_cleanup(struct termios *ti)
 446 {
 447         tcsetattr(0, TCSANOW, ti);
 448         OUT("\r\n\033[?25h");   /* show the cursor */
 449 }
 450
 451 static void mainloop(int vnc_fd, int kbd_fd, int rat_fd)
 452 {
 453         struct pollfd ufds[3];
 454         int pending = 0;
 455         int err;
 456         ufds[0].fd = kbd_fd;
 457         ufds[0].events = POLLIN;
 458         ufds[1].fd = vnc_fd;
 459         ufds[1].events = POLLIN;
 460         ufds[2].fd = rat_fd;
 461         ufds[2].events = POLLIN;
 462         rat_event(vnc_fd, -1);
 463         if (vnc_refresh(vnc_fd, 0))
 464                 return;
 465         while (1) {
 466                 err = poll(ufds, 3, 500);
 467                 if (err == -1 && errno != EINTR)
 468                         break;
 469                 if (!err)
 470                         continue;
 471                 if (ufds[0].revents & POLLIN)
 472                         if (kbd_event(vnc_fd, kbd_fd) == -1)
 473                                 break;
 474                 if (ufds[1].revents & POLLIN) {
 475                         if (vnc_event(vnc_fd) == -1)
 476                                 break;
 477                         pending = 0;
 478                 }
 479                 if (ufds[2].revents & POLLIN)
 480                         if (rat_event(vnc_fd, rat_fd) == -1)
 481                                 break;
 482                 if (!pending++)
 483                         if (vnc_refresh(vnc_fd, 1))
 484                                 break;
 485         }
 486 }
 487
 488 int main(int argc, char * argv[])
 489 {
 490         char *port = VNC_PORT;
 491         char *host = "127.0.0.1";
 492         struct termios ti;
 493         int vnc_fd, rat_fd;
 494         if (argc >= 2 && argv[1][0] && strcmp("-", argv[1]))
 495                 host = argv[1];
 496         if (argc >= 3)
 497                 port = argv[2];
 498         if ((vnc_fd = vnc_connect(host, port)) < 0) {
 499                 fprintf(stderr, "fbvnc: could not connect!\n");
 500                 return 1;
 501         }
 502         if (vnc_init(vnc_fd) < 0) {
 503                 close(vnc_fd);
 504                 fprintf(stderr, "fbvnc: vnc init failed!\n");
 505                 return 1;
 506         }
 507         term_setup(&ti);
 508
 509         /* entering intellimouse for using mouse wheel */
 510         rat_fd = open("/dev/input/mice", O_RDWR);
 511         write(rat_fd, "\xf3\xc8\xf3\x64\xf3\x50", 6);
 512         read(rat_fd, buf, 1);
 513
 514         mainloop(vnc_fd, 0, rat_fd);
 515
 516         term_cleanup(&ti);
 517         vnc_free();
 518         close(vnc_fd);
 519         close(rat_fd);
 520         return 0;
 521 }