std.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <sys/types.h>
   3 #include <sys/wait.h>
   4 #include <ctype.h>
   5 #include <err.h>
   6 #include <fcntl.h>
   7 #if !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
   8 #include <pty.h>
   9 #endif
  10 #include <signal.h>
  11 #include <stdarg.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16
  17 #define LENGTH(x)       (sizeof(x) / sizeof((x)[0]))
  18 #define MAX(a,b)        (((a) > (b)) ? (a) : (b))
  19 #define MIN(a,b)        (((a) < (b)) ? (a) : (b))
  20
  21 typedef struct {
  22         unsigned char data[BUFSIZ];
  23         int s, e;
  24         int n;
  25 } RingBuffer;
  26
  27 typedef struct {
  28         unsigned char data[BUFSIZ];
  29         int i, n;
  30         int fd;
  31 } ReadBuffer;
  32
  33 static void buffer(char c);
  34 static void cmd(const char *cmdstr, ...);
  35 static int getch(ReadBuffer *buf);
  36 static void getpty(void);
  37 static void movea(int x, int y);
  38 static void mover(int x, int y);
  39 static void parsecmd(void);
  40 static void parseesc(void);
  41 static void scroll(int l);
  42 static void shell(void);
  43 static void sigchld(int n);
  44 static char unbuffer(void);
  45 static void ungetch(ReadBuffer *buf, int c);
  46
  47 static int cols = 80, lines = 25;
  48 static int cx = 0, cy = 0;
  49 static int c;
  50 static int ptm, pts;
  51 static _Bool bold, digit, qmark;
  52 static pid_t pid;
  53 static RingBuffer buf;
  54 static ReadBuffer cmdbuf, ptmbuf;
  55
  56 void
  57 buffer(char c) {
  58         if(buf.n < LENGTH(buf.data))
  59                 buf.n++;
  60         else
  61                 buf.s = (buf.s + 1) % LENGTH(buf.data);
  62         buf.data[buf.e++] = c;
  63         buf.e %= LENGTH(buf.data);
  64 }
  65
  66 void
  67 cmd(const char *cmdstr, ...) {
  68         va_list ap;
  69
  70         putchar('\n');
  71         putchar(':');
  72         va_start(ap, cmdstr);
  73         vfprintf(stdout, cmdstr, ap);
  74         va_end(ap);
  75 }
  76
  77 int
  78 getch(ReadBuffer *buf) {
  79         if(buf->i++ >= buf->n) {
  80                 buf->n = read(buf->fd, buf->data, BUFSIZ);
  81                 if(buf->n == -1)
  82                         err(EXIT_FAILURE, "cannot read");
  83                 buf->i = 0;
  84         }
  85         return buf->data[buf->i];
  86 }
  87
  88 void
  89 movea(int x, int y) {
  90         x = MAX(x, cols);
  91         y = MAX(y, lines);
  92         cx = x;
  93         cy = y;
  94         cmd("seek(%d,%d)", x, y);
  95 }
  96
  97 void
  98 mover(int x, int y) {
  99         movea(cx + x, cy + y);
 100 }
 101
 102 void
 103 parsecmd(void) {
 104 }
 105
 106 void
 107 parseesc(void) {
 108         int i, j;
 109         int arg[16];
 110
 111         memset(arg, 0, LENGTH(arg));
 112         c = getch(&ptmbuf);
 113         switch(c) {
 114         case '[':
 115                 c = getch(&ptmbuf);
 116                 for(j = 0; j < LENGTH(arg);) {
 117                         if(isdigit(c)) {
 118                                 digit = 1;
 119                                 arg[j] *= 10;
 120                                 arg[j] += c - '0';
 121                         }
 122                         else if(c == '?')
 123                                 qmark = 1;
 124                         else if(c == ';') {
 125                                 if(!digit)
 126                                         errx(EXIT_FAILURE, "syntax error");
 127                                 digit = 0;
 128                                 j++;
 129                         }
 130                         else {
 131                                 if(digit) {
 132                                         digit = 0;
 133                                         j++;
 134                                 }
 135                                 break;
 136                         }
 137                         c = getch(&ptmbuf);
 138                 }
 139                 switch(c) {
 140                 case '@':
 141                         break;
 142                 case 'A':
 143                         mover(0, j ? arg[0] : 1);
 144                         break;
 145                 case 'B':
 146                         mover(0, j ? -arg[0] : -1);
 147                         break;
 148                 case 'C':
 149                         mover(j ? arg[0] : 1, 0);
 150                         break;
 151                 case 'D':
 152                         mover(j ? -arg[0] : -1, 0);
 153                         break;
 154                 case 'E':
 155                         /* movel(j ? arg[0] : 1); */
 156                         break;
 157                 case 'F':
 158                         /* movel(j ? -arg[0] : -1); */
 159                         break;
 160                 case '`':
 161                 case 'G':
 162                         movea(j ? arg[0] : 1, cy);
 163                         break;
 164                 case 'f':
 165                 case 'H':
 166                         movea(arg[1] ? arg[1] : 1, arg[0] ? arg[0] : 1);
 167                 case 'L':
 168                         /* insline(j ? arg[0] : 1); */
 169                         break;
 170                 case 'M':
 171                         /* delline(j ? arg[0] : 1); */
 172                         break;
 173                 case 'P':
 174                         break;
 175                 case 'S':
 176                         scroll(j ? arg[0] : 1);
 177                         break;
 178                 case 'T':
 179                         scroll(j ? -arg[0] : -1);
 180                         break;
 181                 case 'd':
 182                         movea(cx, j ? arg[0] : 1);
 183                         break;
 184                 case 'm':
 185                         for(i = 0; i < j; i++) {
 186                                 if(arg[i] >= 30 && arg[i] <= 37)
 187                                         cmd("#%d", arg[i] - 30);
 188                                 if(arg[i] >= 40 && arg[i] <= 47)
 189                                         cmd("|%d", arg[i] - 40);
 190                                 /* xterm bright colors */
 191                                 if(arg[i] >= 90 && arg[i] <= 97)
 192                                         cmd("#%d", arg[i] - 90);
 193                                 if(arg[i] >= 100 && arg[i] <= 107)
 194                                         cmd("|%d", arg[i] - 100);
 195                                 switch(arg[i]) {
 196                                 case 0:
 197                                 case 22:
 198                                         if(bold)
 199                                                 cmd("bold");
 200                                 case 1:
 201                                         if(!bold)
 202                                                 cmd("bold");
 203                                         break;
 204                                 }
 205                         }
 206                         break;
 207                 }
 208                 break;
 209         default:
 210                 putchar('\033');
 211                 ungetch(&ptmbuf, c);
 212         }
 213 }
 214
 215 void
 216 scroll(int l) {
 217         cmd("seek(%d,%d)", cx, cy + l);
 218 }
 219
 220 void
 221 getpty(void) {
 222         char *ptsdev;
 223
 224 #if defined(_GNU_SOURCE)
 225         ptm = getpt();
 226 #elif _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600
 227         ptm = posix_openpt(O_RDWR);
 228 #else
 229         ptm = open("/dev/ptmx", O_RDWR);
 230         if(ptm == -1)
 231                 if(openpty(&ptm, &pts, NULL, NULL, NULL) == -1)
 232                         err(EXIT_FAILURE, "cannot open pty");
 233 #endif
 234 #if defined(_XOPEN_SOURCE)
 235         if(ptm != -1) {
 236                 if(grantpt(ptm) == -1)
 237                         err(EXIT_FAILURE, "cannot grant access to pty");
 238                 if(unlockpt(ptm) == -1)
 239                         err(EXIT_FAILURE, "cannot unlock pty");
 240                 ptsdev = ptsname(ptm);
 241                 if(!ptsdev)
 242                         err(EXIT_FAILURE, "slave pty name undefined");
 243                 pts = open(ptsdev, O_RDWR);
 244                 if(pts == -1)
 245                         err(EXIT_FAILURE, "cannot open slave pty");
 246         }
 247         else
 248                 err(EXIT_FAILURE, "cannot open pty");
 249 #endif
 250 }
 251
 252 void
 253 shell(void) {
 254         static char *shell = NULL;
 255
 256         if(!shell && !(shell = getenv("SHELL")))
 257                 shell = "/bin/sh";
 258         pid = fork();
 259         switch(pid) {
 260         case -1:
 261                 err(EXIT_FAILURE, "cannot fork");
 262         case 0:
 263                 setsid();
 264                 dup2(pts, STDIN_FILENO);
 265                 dup2(pts, STDOUT_FILENO);
 266                 dup2(pts, STDERR_FILENO);
 267                 close(ptm);
 268                 putenv("TERM=vt102");
 269                 execvp(shell, NULL);
 270                 break;
 271         default:
 272                 close(pts);
 273                 signal(SIGCHLD, sigchld);
 274         }
 275 }
 276
 277 void
 278 sigchld(int n) {
 279         int ret;
 280
 281         if(waitpid(pid, &ret, 0) == -1)
 282                 err(EXIT_FAILURE, "waiting for child failed");
 283         if(WIFEXITED(ret))
 284                 exit(WEXITSTATUS(ret));
 285         else
 286                 exit(EXIT_SUCCESS);
 287 }
 288
 289 char
 290 unbuffer(void) {
 291         char c;
 292
 293         c = buf.data[buf.s++];
 294         buf.s %= LENGTH(buf.data);
 295         buf.n--;
 296         return c;
 297 }
 298
 299 void
 300 ungetch(ReadBuffer *buf, int c) {
 301         if(buf->i + 1 >= buf->n)
 302                 errx(EXIT_FAILURE, "buffer full");
 303         buf->data[buf->i++] = c;
 304 }
 305
 306 int
 307 main(int argc, char *argv[]) {
 308         fd_set rfds;
 309
 310         if(argc == 2 && !strcmp("-v", argv[1]))
 311                 errx(EXIT_SUCCESS, "std-"VERSION", © 2008 Matthias-Christian Ott");
 312         else if(argc == 1)
 313                 errx(EXIT_FAILURE, "usage: std [-v]");
 314         getpty();
 315         shell();
 316         cmdbuf.fd = STDIN_FILENO;
 317         ptmbuf.fd = ptm;
 318         FD_ZERO(&rfds);
 319         FD_SET(STDIN_FILENO, &rfds);
 320         FD_SET(ptm, &rfds);
 321         for(;;) {
 322                 if(select(ptm + 1, &rfds, NULL, NULL, NULL) == -1)
 323                         err(EXIT_FAILURE, "cannot select");
 324                 if(FD_ISSET(STDIN_FILENO, &rfds))
 325                         do {
 326                                 c = getch(&cmdbuf);
 327                                 switch(c) {
 328                                 case ':':
 329                                         parsecmd();
 330                                         break;
 331                                 default:
 332                                         break;
 333                                 }
 334                         } while(cmdbuf.i < cmdbuf.n);
 335                 if(FD_ISSET(ptm, &rfds)) {
 336                         do {
 337                                 c = getch(&ptmbuf);
 338                                 switch(c) {
 339                                 case '\033':
 340                                         parseesc();
 341                                         break;
 342                                 default:
 343                                         putchar(c);
 344                                 }
 345                         } while(ptmbuf.i < ptmbuf.n);
 346                         fflush(stdout);
 347                 }
 348         }
 349         return 0;
 350 }