1 /*- 2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> /* to pick up __FreeBSD_version */ 31 #include <string.h> 32 #include <stand.h> 33 #include "bootstrap.h" 34 #include "ficl.h" 35 36 extern unsigned bootprog_rev; 37 INTERP_DEFINE("4th"); 38 39 /* #define BFORTH_DEBUG */ 40 41 #ifdef BFORTH_DEBUG 42 #define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args) 43 #else 44 #define DEBUG(fmt, args...) 45 #endif 46 47 /* 48 * Eventually, all builtin commands throw codes must be defined 49 * elsewhere, possibly bootstrap.h. For now, just this code, used 50 * just in this file, it is getting defined. 51 */ 52 #define BF_PARSE 100 53 54 /* 55 * FreeBSD loader default dictionary cells 56 */ 57 #ifndef BF_DICTSIZE 58 #define BF_DICTSIZE 10000 59 #endif 60 61 /* 62 * BootForth Interface to Ficl Forth interpreter. 63 */ 64 65 FICL_SYSTEM *bf_sys; 66 FICL_VM *bf_vm; 67 68 /* 69 * Shim for taking commands from BF and passing them out to 'standard' 70 * argv/argc command functions. 71 */ 72 static void 73 bf_command(FICL_VM *vm) 74 { 75 char *name, *line, *tail, *cp; 76 size_t len; 77 struct bootblk_command **cmdp; 78 bootblk_cmd_t *cmd; 79 int nstrings, i; 80 int argc, result; 81 char **argv; 82 83 /* Get the name of the current word */ 84 name = vm->runningWord->name; 85 86 /* Find our command structure */ 87 cmd = NULL; 88 SET_FOREACH(cmdp, Xcommand_set) { 89 if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name)) 90 cmd = (*cmdp)->c_fn; 91 } 92 if (cmd == NULL) 93 panic("callout for unknown command '%s'", name); 94 95 /* Check whether we have been compiled or are being interpreted */ 96 if (stackPopINT(vm->pStack)) { 97 /* 98 * Get parameters from stack, in the format: 99 * an un ... a2 u2 a1 u1 n -- 100 * Where n is the number of strings, a/u are pairs of 101 * address/size for strings, and they will be concatenated 102 * in LIFO order. 103 */ 104 nstrings = stackPopINT(vm->pStack); 105 for (i = 0, len = 0; i < nstrings; i++) 106 len += stackFetch(vm->pStack, i * 2).i + 1; 107 line = malloc(strlen(name) + len + 1); 108 strcpy(line, name); 109 110 if (nstrings) 111 for (i = 0; i < nstrings; i++) { 112 len = stackPopINT(vm->pStack); 113 cp = stackPopPtr(vm->pStack); 114 strcat(line, " "); 115 strncat(line, cp, len); 116 } 117 } else { 118 /* Get remainder of invocation */ 119 tail = vmGetInBuf(vm); 120 for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++) 121 ; 122 123 line = malloc(strlen(name) + len + 2); 124 strcpy(line, name); 125 if (len > 0) { 126 strcat(line, " "); 127 strncat(line, tail, len); 128 vmUpdateTib(vm, tail + len); 129 } 130 } 131 DEBUG("cmd '%s'", line); 132 133 command_errmsg = command_errbuf; 134 command_errbuf[0] = 0; 135 if (!parse(&argc, &argv, line)) { 136 result = (cmd)(argc, argv); 137 free(argv); 138 } else { 139 result=BF_PARSE; 140 } 141 142 switch (result) { 143 case CMD_CRIT: 144 printf("%s\n", command_errmsg); 145 command_errmsg = NULL; 146 break; 147 case CMD_FATAL: 148 panic("%s", command_errmsg); 149 } 150 151 free(line); 152 /* 153 * If there was error during nested ficlExec(), we may no longer have 154 * valid environment to return. Throw all exceptions from here. 155 */ 156 if (result != CMD_OK) 157 vmThrow(vm, result); 158 159 /* This is going to be thrown!!! */ 160 stackPushINT(vm->pStack,result); 161 } 162 163 /* 164 * Replace a word definition (a builtin command) with another 165 * one that: 166 * 167 * - Throw error results instead of returning them on the stack 168 * - Pass a flag indicating whether the word was compiled or is 169 * being interpreted. 170 * 171 * There is one major problem with builtins that cannot be overcome 172 * in anyway, except by outlawing it. We want builtins to behave 173 * differently depending on whether they have been compiled or they 174 * are being interpreted. Notice that this is *not* the interpreter's 175 * current state. For example: 176 * 177 * : example ls ; immediate 178 * : problem example ; \ "ls" gets executed while compiling 179 * example \ "ls" gets executed while interpreting 180 * 181 * Notice that, though the current state is different in the two 182 * invocations of "example", in both cases "ls" has been 183 * *compiled in*, which is what we really want. 184 * 185 * The problem arises when you tick the builtin. For example: 186 * 187 * : example-1 ['] ls postpone literal ; immediate 188 * : example-2 example-1 execute ; immediate 189 * : problem example-2 ; 190 * example-2 191 * 192 * We have no way, when we get EXECUTEd, of knowing what our behavior 193 * should be. Thus, our only alternative is to "outlaw" this. See RFI 194 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related 195 * problem, concerning compile semantics. 196 * 197 * The problem is compounded by the fact that "' builtin CATCH" is valid 198 * and desirable. The only solution is to create an intermediary word. 199 * For example: 200 * 201 * : my-ls ls ; 202 * : example ['] my-ls catch ; 203 * 204 * So, with the below implementation, here is a summary of the behavior 205 * of builtins: 206 * 207 * ls -l \ "interpret" behavior, ie, 208 * \ takes parameters from TIB 209 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie, 210 * \ takes parameters from the stack 211 * : ex-2 ['] ls catch ; immediate \ undefined behavior 212 * : ex-3 ['] ls catch ; \ undefined behavior 213 * ex-2 ex-3 \ "interpret" behavior, 214 * \ catch works 215 * : ex-4 ex-2 ; \ "compile" behavior, 216 * \ catch does not work 217 * : ex-5 ex-3 ; immediate \ same as ex-2 218 * : ex-6 ex-3 ; \ same as ex-3 219 * : ex-7 ['] ex-1 catch ; \ "compile" behavior, 220 * \ catch works 221 * : ex-8 postpone ls ; immediate \ same as ex-2 222 * : ex-9 postpone ls ; \ same as ex-3 223 * 224 * As the definition below is particularly tricky, and it's side effects 225 * must be well understood by those playing with it, I'll be heavy on 226 * the comments. 227 * 228 * (if you edit this definition, pay attention to trailing spaces after 229 * each word -- I warned you! :-) ) 230 */ 231 #define BUILTIN_CONSTRUCTOR \ 232 ": builtin: " \ 233 ">in @ " /* save the tib index pointer */ \ 234 "' " /* get next word's xt */ \ 235 "swap >in ! " /* point again to next word */ \ 236 "create " /* create a new definition of the next word */ \ 237 ", " /* save previous definition's xt */ \ 238 "immediate " /* make the new definition an immediate word */ \ 239 \ 240 "does> " /* Now, the *new* definition will: */ \ 241 "state @ if " /* if in compiling state: */ \ 242 "1 postpone literal " /* pass 1 flag to indicate compile */ \ 243 "@ compile, " /* compile in previous definition */ \ 244 "postpone throw " /* throw stack-returned result */ \ 245 "else " /* if in interpreting state: */ \ 246 "0 swap " /* pass 0 flag to indicate interpret */ \ 247 "@ execute " /* call previous definition */ \ 248 "throw " /* throw stack-returned result */ \ 249 "then ; " 250 251 /* 252 * Initialise the Forth interpreter, create all our commands as words. 253 */ 254 void 255 bf_init(void) 256 { 257 struct bootblk_command **cmdp; 258 char create_buf[41]; /* 31 characters-long builtins */ 259 int fd; 260 261 bf_sys = ficlInitSystem(BF_DICTSIZE); 262 bf_vm = ficlNewVM(bf_sys); 263 264 /* Put all private definitions in a "builtins" vocabulary */ 265 ficlExec(bf_vm, "vocabulary builtins also builtins definitions"); 266 267 /* Builtin constructor word */ 268 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR); 269 270 /* make all commands appear as Forth words */ 271 SET_FOREACH(cmdp, Xcommand_set) { 272 ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT); 273 ficlExec(bf_vm, "forth definitions builtins"); 274 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name); 275 ficlExec(bf_vm, create_buf); 276 ficlExec(bf_vm, "builtins definitions"); 277 } 278 ficlExec(bf_vm, "only forth definitions"); 279 280 /* Export some version numbers so that code can detect the loader/host version */ 281 ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version); 282 ficlSetEnv(bf_sys, "loader_version", bootprog_rev); 283 284 /* try to load and run init file if present */ 285 if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) { 286 (void)ficlExecFD(bf_vm, fd); 287 close(fd); 288 } 289 } 290 291 /* 292 * Feed a line of user input to the Forth interpreter 293 */ 294 static int 295 bf_run(const char *line) 296 { 297 int result; 298 299 /* 300 * ficl would require extensive changes to accept a const char * 301 * interface. Instead, cast it away here and hope for the best. 302 * We know at the present time the caller for us in the boot 303 * forth loader can tolerate the string being modified because 304 * the string is passed in here and then not touched again. 305 */ 306 result = ficlExec(bf_vm, __DECONST(char *, line)); 307 308 DEBUG("ficlExec '%s' = %d", line, result); 309 switch (result) { 310 case VM_OUTOFTEXT: 311 case VM_ABORTQ: 312 case VM_QUIT: 313 case VM_ERREXIT: 314 break; 315 case VM_USEREXIT: 316 printf("No where to leave to!\n"); 317 break; 318 case VM_ABORT: 319 printf("Aborted!\n"); 320 break; 321 case BF_PARSE: 322 printf("Parse error!\n"); 323 break; 324 default: 325 if (command_errmsg != NULL) { 326 printf("%s\n", command_errmsg); 327 command_errmsg = NULL; 328 } 329 } 330 331 if (result == VM_USEREXIT) 332 panic("interpreter exit"); 333 setenv("interpret", bf_vm->state ? "" : "OK", 1); 334 335 return (result); 336 } 337 338 void 339 interp_init(void) 340 { 341 342 setenv("script.lang", "forth", 1); 343 bf_init(); 344 /* Read our default configuration. */ 345 interp_include("/boot/loader.rc"); 346 } 347 348 int 349 interp_run(const char *input) 350 { 351 352 bf_vm->sourceID.i = 0; 353 return bf_run(input); 354 } 355 356 /* 357 * Header prepended to each line. The text immediately follows the header. 358 * We try to make this short in order to save memory -- the loader has 359 * limited memory available, and some of the forth files are very long. 360 */ 361 struct includeline 362 { 363 struct includeline *next; 364 char text[0]; 365 }; 366 367 int 368 interp_include(const char *filename) 369 { 370 struct includeline *script, *se, *sp; 371 char input[256]; /* big enough? */ 372 int res; 373 char *cp; 374 int prevsrcid, fd, line; 375 376 if (((fd = open(filename, O_RDONLY)) == -1)) { 377 snprintf(command_errbuf, sizeof(command_errbuf), 378 "can't open '%s': %s", filename, strerror(errno)); 379 return(CMD_ERROR); 380 } 381 382 /* 383 * Read the script into memory. 384 */ 385 script = se = NULL; 386 line = 0; 387 388 while (fgetstr(input, sizeof(input), fd) >= 0) { 389 line++; 390 cp = input; 391 /* Allocate script line structure and copy line, flags */ 392 if (*cp == '\0') 393 continue; /* ignore empty line, save memory */ 394 sp = malloc(sizeof(struct includeline) + strlen(cp) + 1); 395 /* On malloc failure (it happens!), free as much as possible and exit */ 396 if (sp == NULL) { 397 while (script != NULL) { 398 se = script; 399 script = script->next; 400 free(se); 401 } 402 snprintf(command_errbuf, sizeof(command_errbuf), 403 "file '%s' line %d: memory allocation failure - aborting", 404 filename, line); 405 close(fd); 406 return (CMD_ERROR); 407 } 408 strcpy(sp->text, cp); 409 sp->next = NULL; 410 411 if (script == NULL) { 412 script = sp; 413 } else { 414 se->next = sp; 415 } 416 se = sp; 417 } 418 close(fd); 419 420 /* 421 * Execute the script 422 */ 423 prevsrcid = bf_vm->sourceID.i; 424 bf_vm->sourceID.i = fd; 425 res = CMD_OK; 426 for (sp = script; sp != NULL; sp = sp->next) { 427 res = bf_run(sp->text); 428 if (res != VM_OUTOFTEXT) { 429 snprintf(command_errbuf, sizeof(command_errbuf), 430 "Error while including %s, in the line:\n%s", 431 filename, sp->text); 432 res = CMD_ERROR; 433 break; 434 } else 435 res = CMD_OK; 436 } 437 bf_vm->sourceID.i = prevsrcid; 438 439 while (script != NULL) { 440 se = script; 441 script = script->next; 442 free(se); 443 } 444 return(res); 445 } 446