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 break; 146 case CMD_FATAL: 147 panic("%s\n", command_errmsg); 148 } 149 150 free(line); 151 /* 152 * If there was error during nested ficlExec(), we may no longer have 153 * valid environment to return. Throw all exceptions from here. 154 */ 155 if (result != CMD_OK) 156 vmThrow(vm, result); 157 158 /* This is going to be thrown!!! */ 159 stackPushINT(vm->pStack,result); 160 } 161 162 /* 163 * Replace a word definition (a builtin command) with another 164 * one that: 165 * 166 * - Throw error results instead of returning them on the stack 167 * - Pass a flag indicating whether the word was compiled or is 168 * being interpreted. 169 * 170 * There is one major problem with builtins that cannot be overcome 171 * in anyway, except by outlawing it. We want builtins to behave 172 * differently depending on whether they have been compiled or they 173 * are being interpreted. Notice that this is *not* the interpreter's 174 * current state. For example: 175 * 176 * : example ls ; immediate 177 * : problem example ; \ "ls" gets executed while compiling 178 * example \ "ls" gets executed while interpreting 179 * 180 * Notice that, though the current state is different in the two 181 * invocations of "example", in both cases "ls" has been 182 * *compiled in*, which is what we really want. 183 * 184 * The problem arises when you tick the builtin. For example: 185 * 186 * : example-1 ['] ls postpone literal ; immediate 187 * : example-2 example-1 execute ; immediate 188 * : problem example-2 ; 189 * example-2 190 * 191 * We have no way, when we get EXECUTEd, of knowing what our behavior 192 * should be. Thus, our only alternative is to "outlaw" this. See RFI 193 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related 194 * problem, concerning compile semantics. 195 * 196 * The problem is compounded by the fact that "' builtin CATCH" is valid 197 * and desirable. The only solution is to create an intermediary word. 198 * For example: 199 * 200 * : my-ls ls ; 201 * : example ['] my-ls catch ; 202 * 203 * So, with the below implementation, here is a summary of the behavior 204 * of builtins: 205 * 206 * ls -l \ "interpret" behavior, ie, 207 * \ takes parameters from TIB 208 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie, 209 * \ takes parameters from the stack 210 * : ex-2 ['] ls catch ; immediate \ undefined behavior 211 * : ex-3 ['] ls catch ; \ undefined behavior 212 * ex-2 ex-3 \ "interpret" behavior, 213 * \ catch works 214 * : ex-4 ex-2 ; \ "compile" behavior, 215 * \ catch does not work 216 * : ex-5 ex-3 ; immediate \ same as ex-2 217 * : ex-6 ex-3 ; \ same as ex-3 218 * : ex-7 ['] ex-1 catch ; \ "compile" behavior, 219 * \ catch works 220 * : ex-8 postpone ls ; immediate \ same as ex-2 221 * : ex-9 postpone ls ; \ same as ex-3 222 * 223 * As the definition below is particularly tricky, and it's side effects 224 * must be well understood by those playing with it, I'll be heavy on 225 * the comments. 226 * 227 * (if you edit this definition, pay attention to trailing spaces after 228 * each word -- I warned you! :-) ) 229 */ 230 #define BUILTIN_CONSTRUCTOR \ 231 ": builtin: " \ 232 ">in @ " /* save the tib index pointer */ \ 233 "' " /* get next word's xt */ \ 234 "swap >in ! " /* point again to next word */ \ 235 "create " /* create a new definition of the next word */ \ 236 ", " /* save previous definition's xt */ \ 237 "immediate " /* make the new definition an immediate word */ \ 238 \ 239 "does> " /* Now, the *new* definition will: */ \ 240 "state @ if " /* if in compiling state: */ \ 241 "1 postpone literal " /* pass 1 flag to indicate compile */ \ 242 "@ compile, " /* compile in previous definition */ \ 243 "postpone throw " /* throw stack-returned result */ \ 244 "else " /* if in interpreting state: */ \ 245 "0 swap " /* pass 0 flag to indicate interpret */ \ 246 "@ execute " /* call previous definition */ \ 247 "throw " /* throw stack-returned result */ \ 248 "then ; " 249 250 /* 251 * Initialise the Forth interpreter, create all our commands as words. 252 */ 253 void 254 bf_init(void) 255 { 256 struct bootblk_command **cmdp; 257 char create_buf[41]; /* 31 characters-long builtins */ 258 int fd; 259 260 bf_sys = ficlInitSystem(BF_DICTSIZE); 261 bf_vm = ficlNewVM(bf_sys); 262 263 /* Put all private definitions in a "builtins" vocabulary */ 264 ficlExec(bf_vm, "vocabulary builtins also builtins definitions"); 265 266 /* Builtin constructor word */ 267 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR); 268 269 /* make all commands appear as Forth words */ 270 SET_FOREACH(cmdp, Xcommand_set) { 271 ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT); 272 ficlExec(bf_vm, "forth definitions builtins"); 273 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name); 274 ficlExec(bf_vm, create_buf); 275 ficlExec(bf_vm, "builtins definitions"); 276 } 277 ficlExec(bf_vm, "only forth definitions"); 278 279 /* Export some version numbers so that code can detect the loader/host version */ 280 ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version); 281 ficlSetEnv(bf_sys, "loader_version", bootprog_rev); 282 283 /* try to load and run init file if present */ 284 if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) { 285 (void)ficlExecFD(bf_vm, fd); 286 close(fd); 287 } 288 } 289 290 /* 291 * Feed a line of user input to the Forth interpreter 292 */ 293 static int 294 bf_run(const char *line) 295 { 296 int result; 297 298 /* 299 * ficl would require extensive changes to accept a const char * 300 * interface. Instead, cast it away here and hope for the best. 301 * We know at the present time the caller for us in the boot 302 * forth loader can tolerate the string being modified because 303 * the string is passed in here and then not touched again. 304 */ 305 result = ficlExec(bf_vm, __DECONST(char *, line)); 306 307 DEBUG("ficlExec '%s' = %d", line, result); 308 switch (result) { 309 case VM_OUTOFTEXT: 310 case VM_ABORTQ: 311 case VM_QUIT: 312 case VM_ERREXIT: 313 break; 314 case VM_USEREXIT: 315 printf("No where to leave to!\n"); 316 break; 317 case VM_ABORT: 318 printf("Aborted!\n"); 319 break; 320 case BF_PARSE: 321 printf("Parse error!\n"); 322 break; 323 default: 324 if (command_errmsg != NULL) { 325 printf("%s\n", command_errmsg); 326 command_errmsg = NULL; 327 } 328 } 329 330 if (result == VM_USEREXIT) 331 panic("interpreter exit"); 332 setenv("interpret", bf_vm->state ? "" : "OK", 1); 333 334 return (result); 335 } 336 337 void 338 interp_init(void) 339 { 340 341 setenv("script.lang", "forth", 1); 342 bf_init(); 343 /* Read our default configuration. */ 344 interp_include("/boot/loader.rc"); 345 } 346 347 int 348 interp_run(const char *input) 349 { 350 351 bf_vm->sourceID.i = 0; 352 return bf_run(input); 353 } 354 355 /* 356 * Header prepended to each line. The text immediately follows the header. 357 * We try to make this short in order to save memory -- the loader has 358 * limited memory available, and some of the forth files are very long. 359 */ 360 struct includeline 361 { 362 struct includeline *next; 363 char text[0]; 364 }; 365 366 int 367 interp_include(const char *filename) 368 { 369 struct includeline *script, *se, *sp; 370 char input[256]; /* big enough? */ 371 int res; 372 char *cp; 373 int prevsrcid, fd, line; 374 375 if (((fd = open(filename, O_RDONLY)) == -1)) { 376 snprintf(command_errbuf, sizeof(command_errbuf), 377 "can't open '%s': %s", filename, strerror(errno)); 378 return(CMD_ERROR); 379 } 380 381 /* 382 * Read the script into memory. 383 */ 384 script = se = NULL; 385 line = 0; 386 387 while (fgetstr(input, sizeof(input), fd) >= 0) { 388 line++; 389 cp = input; 390 /* Allocate script line structure and copy line, flags */ 391 if (*cp == '\0') 392 continue; /* ignore empty line, save memory */ 393 sp = malloc(sizeof(struct includeline) + strlen(cp) + 1); 394 /* On malloc failure (it happens!), free as much as possible and exit */ 395 if (sp == NULL) { 396 while (script != NULL) { 397 se = script; 398 script = script->next; 399 free(se); 400 } 401 snprintf(command_errbuf, sizeof(command_errbuf), 402 "file '%s' line %d: memory allocation failure - aborting", 403 filename, line); 404 close(fd); 405 return (CMD_ERROR); 406 } 407 strcpy(sp->text, cp); 408 sp->next = NULL; 409 410 if (script == NULL) { 411 script = sp; 412 } else { 413 se->next = sp; 414 } 415 se = sp; 416 } 417 close(fd); 418 419 /* 420 * Execute the script 421 */ 422 prevsrcid = bf_vm->sourceID.i; 423 bf_vm->sourceID.i = fd; 424 res = CMD_OK; 425 for (sp = script; sp != NULL; sp = sp->next) { 426 res = bf_run(sp->text); 427 if (res != VM_OUTOFTEXT) { 428 snprintf(command_errbuf, sizeof(command_errbuf), 429 "Error while including %s, in the line:\n%s", 430 filename, sp->text); 431 res = CMD_ERROR; 432 break; 433 } else 434 res = CMD_OK; 435 } 436 bf_vm->sourceID.i = prevsrcid; 437 438 while (script != NULL) { 439 se = script; 440 script = script->next; 441 free(se); 442 } 443 return(res); 444 } 445