std.c

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