fbvnc.c

   1 /*
   2  * FBVNC: a small Linux framebuffer VNC viewer
   3  *
   4  * Copyright (C) 2009-2020 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
  53 static char buf[MAXRES];
  54
  55 static int vnc_connect(char *addr, char *port)
  56 {
  57         struct addrinfo hints, *addrinfo;
  58         int fd;
  59
  60         memset(&hints, 0, sizeof(hints));
  61         hints.ai_family = AF_UNSPEC;
  62         hints.ai_socktype = SOCK_STREAM;
  63         hints.ai_flags = AI_PASSIVE;
  64
  65         if (getaddrinfo(addr, port, &hints, &addrinfo))
  66                 return -1;
  67         fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
  68                         addrinfo->ai_protocol);
  69
  70         if (connect(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) == -1) {
  71                 close(fd);
  72                 freeaddrinfo(addrinfo);
  73                 return -1;
  74         }
  75         freeaddrinfo(addrinfo);
  76         return fd;
  77 }
  78
  79 static void fbmode_bits(int *rr, int *rg, int *rb)
  80 {
  81         int mode = FBM_COLORS(fb_mode());
  82         *rr = (mode >> 8) & 0xf;
  83         *rg = (mode >> 4) & 0xf;
  84         *rb = (mode >> 0) & 0xf;
  85 }
  86
  87 static int vnc_init(int fd)
  88 {
  89         char vncver[16];
  90         int rr, rg, rb;
  91
  92         struct vnc_client_init clientinit;
  93         struct vnc_server_init serverinit;
  94         struct vnc_client_pixelfmt pixfmt_cmd;
  95         int connstat = VNC_CONN_FAILED;
  96
  97         read(fd, vncver, 12);
  98         strcpy(vncver, "RFB 003.003\n");
  99         write(fd, vncver, 12);
 100
 101         read(fd, &connstat, sizeof(connstat));
 102
 103         if (ntohl(connstat) != VNC_CONN_NOAUTH)
 104                 return -1;
 105
 106         clientinit.shared = 1;
 107         write(fd, &clientinit, sizeof(clientinit));
 108         read(fd, &serverinit, sizeof(serverinit));
 109
 110         if (fb_init())
 111                 return -1;
 112         srv_cols = ntohs(serverinit.w);
 113         srv_rows = ntohs(serverinit.h);
 114         cols = MIN(srv_cols, fb_cols());
 115         rows = MIN(srv_rows, fb_rows());
 116         bpp = FBM_BPP(fb_mode());
 117         mr = rows / 2;
 118         mc = cols / 2;
 119
 120         read(fd, buf, ntohl(serverinit.len));
 121         pixfmt_cmd.type = VNC_CLIENT_PIXFMT;
 122         pixfmt_cmd.format.bpp = bpp << 3;
 123         pixfmt_cmd.format.depth = bpp << 3;
 124         pixfmt_cmd.format.bigendian = 0;
 125         pixfmt_cmd.format.truecolor = 1;
 126
 127         fbmode_bits(&rr, &rg, &rb);
 128         pixfmt_cmd.format.rmax = htons((1 << rr) - 1);
 129         pixfmt_cmd.format.gmax = htons((1 << rg) - 1);
 130         pixfmt_cmd.format.bmax = htons((1 << rb) - 1);
 131         /* assuming colors packed as RGB; shall handle other cases later */
 132         pixfmt_cmd.format.rshl = rg + rb;
 133         pixfmt_cmd.format.gshl = rb;
 134         pixfmt_cmd.format.bshl = 0;
 135         write(fd, &pixfmt_cmd, sizeof(pixfmt_cmd));
 136         return 0;
 137 }
 138
 139 static int vnc_free(void)
 140 {
 141         fb_free();
 142         return 0;
 143 }
 144
 145 static int vnc_refresh(int fd, int inc)
 146 {
 147         struct vnc_client_fbup fbup_req;
 148         fbup_req.type = VNC_CLIENT_FBUP;
 149         fbup_req.inc = inc;
 150         fbup_req.x = htons(oc);
 151         fbup_req.y = htons(or);
 152         fbup_req.w = htons(cols);
 153         fbup_req.h = htons(rows);
 154         return write(fd, &fbup_req, sizeof(fbup_req)) != sizeof(fbup_req);
 155 }
 156
 157 static void drawfb(char *s, int x, int y, int w, int h)
 158 {
 159         int sc;         /* screen column offset */
 160         int bc, bw;     /* buffer column offset / row width */
 161         int i;
 162         sc = MAX(0, x - oc);
 163         bc = x > oc ? 0 : oc - x;
 164         bw = x + w < oc + cols ? w - bc : w - bc - (x + w - oc - cols);
 165         for (i = y; i < y + h; i++)
 166                 if (i - or >= 0 && i - or < rows && bw > 0)
 167                         fb_set(i - or, sc, s + ((i - y) * w + bc) * bpp, bw);
 168 }
 169
 170 static void xread(int fd, void *buf, int len)
 171 {
 172         int nr = 0;
 173         int n;
 174         while (nr < len && (n = read(fd, buf + nr, len - nr)) > 0)
 175                 nr += n;
 176         if (nr < len) {
 177                 printf("partial vnc read!\n");
 178                 exit(1);
 179         }
 180 }
 181
 182 static int vnc_event(int fd)
 183 {
 184         struct vnc_rect uprect;
 185         char msg[1 << 12];
 186         struct vnc_server_fbup *fbup = (void *) msg;
 187         struct vnc_server_cuttext *cuttext = (void *) msg;
 188         struct vnc_server_colormap *colormap = (void *) msg;
 189         int i, j;
 190         int n;
 191
 192         if (read(fd, msg, 1) != 1)
 193                 return -1;
 194         switch (msg[0]) {
 195         case VNC_SERVER_FBUP:
 196                 xread(fd, msg + 1, sizeof(*fbup) - 1);
 197                 n = ntohs(fbup->n);
 198                 for (j = 0; j < n; j++) {
 199                         int x, y, w, h;
 200                         xread(fd, &uprect, sizeof(uprect));
 201                         x = ntohs(uprect.x);
 202                         y = ntohs(uprect.y);
 203                         w = ntohs(uprect.w);
 204                         h = ntohs(uprect.h);
 205                         if (x >= srv_cols || x + w > srv_cols)
 206                                 return -1;
 207                         if (y >= srv_rows || y + h > srv_rows)
 208                                 return -1;
 209                         for (i = 0; i < h; i++) {
 210                                 xread(fd, buf, w * bpp);
 211                                 if (!nodraw)
 212                                         drawfb(buf, x, y + i, w, 1);
 213                         }
 214                 }
 215                 break;
 216         case VNC_SERVER_BELL:
 217                 break;
 218         case VNC_SERVER_CUTTEXT:
 219                 xread(fd, msg + 1, sizeof(*cuttext) - 1);
 220                 xread(fd, buf, ntohl(cuttext->len));
 221                 break;
 222         case VNC_SERVER_COLORMAP:
 223                 xread(fd, msg + 1, sizeof(*colormap) - 1);
 224                 xread(fd, buf, ntohs(colormap->n) * 3 * 2);
 225                 break;
 226         default:
 227                 fprintf(stderr, "unknown vnc msg: %d\n", msg[0]);
 228                 return -1;
 229         }
 230         return 0;
 231 }
 232
 233 static int rat_event(int fd, int ratfd)
 234 {
 235         char ie[4];
 236         struct vnc_client_ratevent me = {VNC_CLIENT_RATEVENT};
 237         int mask = 0;
 238         int or_ = or, oc_ = oc;
 239         if (read(ratfd, &ie, sizeof(ie)) != 4)
 240                 return -1;
 241         /* ignore mouse movements when nodraw */
 242         if (nodraw)
 243                 return 0;
 244         mc += ie[1];
 245         mr -= ie[2];
 246
 247         if (mc < oc)
 248                 oc = MAX(0, oc - cols / SCRSCRL);
 249         if (mc >= oc + cols && oc + cols < srv_cols)
 250                 oc = MIN(srv_cols - cols, oc + cols / SCRSCRL);
 251         if (mr < or)
 252                 or = MAX(0, or - rows / SCRSCRL);
 253         if (mr >= or + rows && or + rows < srv_rows)
 254                 or = MIN(srv_rows - rows, or + rows / SCRSCRL);
 255         mc = MAX(oc, MIN(oc + cols - 1, mc));
 256         mr = MAX(or, MIN(or + rows - 1, mr));
 257         if (ie[0] & 0x01)
 258                 mask |= VNC_BUTTON1_MASK;
 259         if (ie[0] & 0x04)
 260                 mask |= VNC_BUTTON2_MASK;
 261         if (ie[0] & 0x02)
 262                 mask |= VNC_BUTTON3_MASK;
 263         if (ie[3] > 0)          /* wheel up */
 264                 mask |= VNC_BUTTON4_MASK;
 265         if (ie[3] < 0)          /* wheel down */
 266                 mask |= VNC_BUTTON5_MASK;
 267
 268         me.y = htons(mr);
 269         me.x = htons(mc);
 270         me.mask = mask;
 271         write(fd, &me, sizeof(me));
 272         if (or != or_ || oc != oc_)
 273                 if (vnc_refresh(fd, 0))
 274                         return -1;
 275         return 0;
 276 }
 277
 278 static int press(int fd, int key, int down)
 279 {
 280         struct vnc_client_keyevent ke = {VNC_CLIENT_KEYEVENT};
 281         ke.key = htonl(key);
 282         ke.down = down;
 283         return write(fd, &ke, sizeof(ke));
 284 }
 285
 286 static void showmsg(void)
 287 {
 288         OUT("\x1b[H\t\t\t*** fbvnc ***\r");
 289 }
 290
 291 static int kbd_event(int fd, int kbdfd)
 292 {
 293         char key[1024];
 294         int i, nr;
 295
 296         if ((nr = read(kbdfd, key, sizeof(key))) <= 0 )
 297                 return -1;
 298         for (i = 0; i < nr; i++) {
 299                 int k = -1;
 300                 int mod[4];
 301                 int nmod = 0;
 302                 switch (key[i]) {
 303                 case 0x08:
 304                 case 0x7f:
 305                         k = 0xff08;
 306                         break;
 307                 case 0x09:
 308                         k = 0xff09;
 309                         break;
 310                 case 0x1b:
 311                         if (i + 2 < nr && key[i + 1] == '[') {
 312                                 if (key[i + 2] == 'A')
 313                                         k = 0xff52;
 314                                 if (key[i + 2] == 'B')
 315                                         k = 0xff54;
 316                                 if (key[i + 2] == 'C')
 317                                         k = 0xff53;
 318                                 if (key[i + 2] == 'D')
 319                                         k = 0xff51;
 320                                 if (key[i + 2] == 'H')
 321                                         k = 0xff50;
 322                                 if (k > 0) {
 323                                         i += 2;
 324                                         break;
 325                                 }
 326                         }
 327                         k = 0xff1b;
 328                         if (i + 1 < nr) {
 329                                 mod[nmod++] = 0xffe9;
 330                                 k = key[++i];
 331                                 if (k == 0x03)  /* esc-^C: quit */
 332                                         return -1;
 333                         }
 334                         break;
 335                 case 0x0d:
 336                         k = 0xff0d;
 337                         break;
 338                 case 0x0:       /* c-space: stop/start drawing */
 339                         if (!nodraw) {
 340                                 nodraw = 1;
 341                                 showmsg();
 342                         } else {
 343                                 nodraw = 0;
 344                                 if (vnc_refresh(fd, 0))
 345                                         return -1;
 346                         }
 347                 default:
 348                         k = (unsigned char) key[i];
 349                 }
 350                 if (k >= 'A' && k <= 'Z' || strchr(":\"<>?{}|+_()*&^%$#@!~", k))
 351                         mod[nmod++] = 0xffe1;
 352                 if (k >= 1 && k <= 26) {
 353                         k = 'a' + k - 1;
 354                         mod[nmod++] = 0xffe3;
 355                 }
 356                 if (k > 0) {
 357                         int j;
 358                         for (j = 0; j < nmod; j++)
 359                                 press(fd, mod[j], 1);
 360                         press(fd, k, 1);
 361                         press(fd, k, 0);
 362                         for (j = 0; j < nmod; j++)
 363                                 press(fd, mod[j], 0);
 364                 }
 365         }
 366         return 0;
 367 }
 368
 369 static void term_setup(struct termios *ti)
 370 {
 371         struct termios termios;
 372         OUT("\033[2J");         /* clear the screen */
 373         OUT("\033[?25l");       /* hide the cursor */
 374         showmsg();
 375         tcgetattr(0, &termios);
 376         *ti = termios;
 377         cfmakeraw(&termios);
 378         tcsetattr(0, TCSANOW, &termios);
 379 }
 380
 381 static void term_cleanup(struct termios *ti)
 382 {
 383         tcsetattr(0, TCSANOW, ti);
 384         OUT("\r\n\033[?25h");   /* show the cursor */
 385 }
 386
 387 static void mainloop(int vnc_fd, int kbd_fd, int rat_fd)
 388 {
 389         struct pollfd ufds[3];
 390         int pending = 0;
 391         int err;
 392         ufds[0].fd = kbd_fd;
 393         ufds[0].events = POLLIN;
 394         ufds[1].fd = vnc_fd;
 395         ufds[1].events = POLLIN;
 396         ufds[2].fd = rat_fd;
 397         ufds[2].events = POLLIN;
 398         if (vnc_refresh(vnc_fd, 0))
 399                 return;
 400         while (1) {
 401                 err = poll(ufds, 3, 500);
 402                 if (err == -1 && errno != EINTR)
 403                         break;
 404                 if (!err)
 405                         continue;
 406                 if (ufds[0].revents & POLLIN)
 407                         if (kbd_event(vnc_fd, kbd_fd) == -1)
 408                                 break;
 409                 if (ufds[1].revents & POLLIN) {
 410                         if (vnc_event(vnc_fd) == -1)
 411                                 break;
 412                         pending = 0;
 413                 }
 414                 if (ufds[2].revents & POLLIN)
 415                         if (rat_event(vnc_fd, rat_fd) == -1)
 416                                 break;
 417                 if (!pending++)
 418                         if (vnc_refresh(vnc_fd, 1))
 419                                 break;
 420         }
 421 }
 422
 423 int main(int argc, char * argv[])
 424 {
 425         char *port = VNC_PORT;
 426         char *host = "127.0.0.1";
 427         struct termios ti;
 428         int vnc_fd, rat_fd;
 429         if (argc >= 2)
 430                 host = argv[1];
 431         if (argc >= 3)
 432                 port = argv[2];
 433         if ((vnc_fd = vnc_connect(host, port)) < 0) {
 434                 fprintf(stderr, "could not connect!\n");
 435                 return 1;
 436         }
 437         if (vnc_init(vnc_fd) < 0) {
 438                 close(vnc_fd);
 439                 fprintf(stderr, "vnc init failed!\n");
 440                 return 1;
 441         }
 442         term_setup(&ti);
 443
 444         /* entering intellimouse for using mouse wheel */
 445         rat_fd = open("/dev/input/mice", O_RDWR);
 446         write(rat_fd, "\xf3\xc8\xf3\x64\xf3\x50", 6);
 447         read(rat_fd, buf, 1);
 448
 449         mainloop(vnc_fd, 0, rat_fd);
 450
 451         term_cleanup(&ti);
 452         vnc_free();
 453         close(vnc_fd);
 454         close(rat_fd);
 455         return 0;
 456 }