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