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 38 /* #define BFORTH_DEBUG */ 39 40 #ifdef BFORTH_DEBUG 41 #define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args) 42 #else 43 #define DEBUG(fmt, args...) 44 #endif 45 46 /* 47 * Eventually, all builtin commands throw codes must be defined 48 * elsewhere, possibly bootstrap.h. For now, just this code, used 49 * just in this file, it is getting defined. 50 */ 51 #define BF_PARSE 100 52 53 /* 54 * FreeBSD loader default dictionary cells 55 */ 56 #ifndef BF_DICTSIZE 57 #define BF_DICTSIZE 10000 58 #endif 59 60 /* 61 * BootForth Interface to Ficl Forth interpreter. 62 */ 63 64 FICL_SYSTEM *bf_sys; 65 FICL_VM *bf_vm; 66 67 /* 68 * Shim for taking commands from BF and passing them out to 'standard' 69 * argv/argc command functions. 70 */ 71 static void 72 bf_command(FICL_VM *vm) 73 { 74 char *name, *line, *tail, *cp; 75 size_t len; 76 struct bootblk_command **cmdp; 77 bootblk_cmd_t *cmd; 78 int nstrings, i; 79 int argc, result; 80 char **argv; 81 82 /* Get the name of the current word */ 83 name = vm->runningWord->name; 84 85 /* Find our command structure */ 86 cmd = NULL; 87 SET_FOREACH(cmdp, Xcommand_set) { 88 if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name)) 89 cmd = (*cmdp)->c_fn; 90 } 91 if (cmd == NULL) 92 panic("callout for unknown command '%s'", name); 93 94 /* Check whether we have been compiled or are being interpreted */ 95 if (stackPopINT(vm->pStack)) { 96 /* 97 * Get parameters from stack, in the format: 98 * an un ... a2 u2 a1 u1 n -- 99 * Where n is the number of strings, a/u are pairs of 100 * address/size for strings, and they will be concatenated 101 * in LIFO order. 102 */ 103 nstrings = stackPopINT(vm->pStack); 104 for (i = 0, len = 0; i < nstrings; i++) 105 len += stackFetch(vm->pStack, i * 2).i + 1; 106 line = malloc(strlen(name) + len + 1); 107 strcpy(line, name); 108 109 if (nstrings) 110 for (i = 0; i < nstrings; i++) { 111 len = stackPopINT(vm->pStack); 112 cp = stackPopPtr(vm->pStack); 113 strcat(line, " "); 114 strncat(line, cp, len); 115 } 116 } else { 117 /* Get remainder of invocation */ 118 tail = vmGetInBuf(vm); 119 for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++) 120 ; 121 122 line = malloc(strlen(name) + len + 2); 123 strcpy(line, name); 124 if (len > 0) { 125 strcat(line, " "); 126 strncat(line, tail, len); 127 vmUpdateTib(vm, tail + len); 128 } 129 } 130 DEBUG("cmd '%s'", line); 131 132 command_errmsg = command_errbuf; 133 command_errbuf[0] = 0; 134 if (!parse(&argc, &argv, line)) { 135 result = (cmd)(argc, argv); 136 free(argv); 137 } else { 138 result=BF_PARSE; 139 } 140 141 switch (result) { 142 case CMD_CRIT: 143 printf("%s\n", command_errmsg); 144 break; 145 case CMD_FATAL: 146 panic("%s\n", command_errmsg); 147 } 148 149 free(line); 150 /* 151 * If there was error during nested ficlExec(), we may no longer have 152 * valid environment to return. Throw all exceptions from here. 153 */ 154 if (result != CMD_OK) 155 vmThrow(vm, result); 156 157 /* This is going to be thrown!!! */ 158 stackPushINT(vm->pStack,result); 159 } 160 161 /* 162 * Replace a word definition (a builtin command) with another 163 * one that: 164 * 165 * - Throw error results instead of returning them on the stack 166 * - Pass a flag indicating whether the word was compiled or is 167 * being interpreted. 168 * 169 * There is one major problem with builtins that cannot be overcome 170 * in anyway, except by outlawing it. We want builtins to behave 171 * differently depending on whether they have been compiled or they 172 * are being interpreted. Notice that this is *not* the interpreter's 173 * current state. For example: 174 * 175 * : example ls ; immediate 176 * : problem example ; \ "ls" gets executed while compiling 177 * example \ "ls" gets executed while interpreting 178 * 179 * Notice that, though the current state is different in the two 180 * invocations of "example", in both cases "ls" has been 181 * *compiled in*, which is what we really want. 182 * 183 * The problem arises when you tick the builtin. For example: 184 * 185 * : example-1 ['] ls postpone literal ; immediate 186 * : example-2 example-1 execute ; immediate 187 * : problem example-2 ; 188 * example-2 189 * 190 * We have no way, when we get EXECUTEd, of knowing what our behavior 191 * should be. Thus, our only alternative is to "outlaw" this. See RFI 192 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related 193 * problem, concerning compile semantics. 194 * 195 * The problem is compounded by the fact that "' builtin CATCH" is valid 196 * and desirable. The only solution is to create an intermediary word. 197 * For example: 198 * 199 * : my-ls ls ; 200 * : example ['] my-ls catch ; 201 * 202 * So, with the below implementation, here is a summary of the behavior 203 * of builtins: 204 * 205 * ls -l \ "interpret" behavior, ie, 206 * \ takes parameters from TIB 207 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie, 208 * \ takes parameters from the stack 209 * : ex-2 ['] ls catch ; immediate \ undefined behavior 210 * : ex-3 ['] ls catch ; \ undefined behavior 211 * ex-2 ex-3 \ "interpret" behavior, 212 * \ catch works 213 * : ex-4 ex-2 ; \ "compile" behavior, 214 * \ catch does not work 215 * : ex-5 ex-3 ; immediate \ same as ex-2 216 * : ex-6 ex-3 ; \ same as ex-3 217 * : ex-7 ['] ex-1 catch ; \ "compile" behavior, 218 * \ catch works 219 * : ex-8 postpone ls ; immediate \ same as ex-2 220 * : ex-9 postpone ls ; \ same as ex-3 221 * 222 * As the definition below is particularly tricky, and it's side effects 223 * must be well understood by those playing with it, I'll be heavy on 224 * the comments. 225 * 226 * (if you edit this definition, pay attention to trailing spaces after 227 * each word -- I warned you! :-) ) 228 */ 229 #define BUILTIN_CONSTRUCTOR \ 230 ": builtin: " \ 231 ">in @ " /* save the tib index pointer */ \ 232 "' " /* get next word's xt */ \ 233 "swap >in ! " /* point again to next word */ \ 234 "create " /* create a new definition of the next word */ \ 235 ", " /* save previous definition's xt */ \ 236 "immediate " /* make the new definition an immediate word */ \ 237 \ 238 "does> " /* Now, the *new* definition will: */ \ 239 "state @ if " /* if in compiling state: */ \ 240 "1 postpone literal " /* pass 1 flag to indicate compile */ \ 241 "@ compile, " /* compile in previous definition */ \ 242 "postpone throw " /* throw stack-returned result */ \ 243 "else " /* if in interpreting state: */ \ 244 "0 swap " /* pass 0 flag to indicate interpret */ \ 245 "@ execute " /* call previous definition */ \ 246 "throw " /* throw stack-returned result */ \ 247 "then ; " 248 249 /* 250 * Initialise the Forth interpreter, create all our commands as words. 251 */ 252 void 253 bf_init(const char *rc) 254 { 255 struct bootblk_command **cmdp; 256 char create_buf[41]; /* 31 characters-long builtins */ 257 int fd; 258 259 bf_sys = ficlInitSystem(BF_DICTSIZE); 260 bf_vm = ficlNewVM(bf_sys); 261 262 /* Put all private definitions in a "builtins" vocabulary */ 263 ficlExec(bf_vm, "vocabulary builtins also builtins definitions"); 264 265 /* Builtin constructor word */ 266 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR); 267 268 /* make all commands appear as Forth words */ 269 SET_FOREACH(cmdp, Xcommand_set) { 270 ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT); 271 ficlExec(bf_vm, "forth definitions builtins"); 272 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name); 273 ficlExec(bf_vm, create_buf); 274 ficlExec(bf_vm, "builtins definitions"); 275 } 276 ficlExec(bf_vm, "only forth definitions"); 277 278 /* Export some version numbers so that code can detect the loader/host version */ 279 ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version); 280 ficlSetEnv(bf_sys, "loader_version", bootprog_rev); 281 282 /* try to load and run init file if present */ 283 if (rc == NULL) 284 rc = "/boot/boot.4th"; 285 if (*rc != '\0') { 286 fd = open(rc, O_RDONLY); 287 if (fd != -1) { 288 (void)ficlExecFD(bf_vm, fd); 289 close(fd); 290 } 291 } 292 } 293 294 /* 295 * Feed a line of user input to the Forth interpreter 296 */ 297 int 298 bf_run(char *line) 299 { 300 int result; 301 302 result = ficlExec(bf_vm, line); 303 304 DEBUG("ficlExec '%s' = %d", line, result); 305 switch (result) { 306 case VM_OUTOFTEXT: 307 case VM_ABORTQ: 308 case VM_QUIT: 309 case VM_ERREXIT: 310 break; 311 case VM_USEREXIT: 312 printf("No where to leave to!\n"); 313 break; 314 case VM_ABORT: 315 printf("Aborted!\n"); 316 break; 317 case BF_PARSE: 318 printf("Parse error!\n"); 319 break; 320 default: 321 if (command_errmsg != NULL) { 322 printf("%s\n", command_errmsg); 323 command_errmsg = NULL; 324 } 325 } 326 327 if (result == VM_USEREXIT) 328 panic("interpreter exit"); 329 setenv("interpret", bf_vm->state ? "" : "OK", 1); 330 331 return (result); 332 } 333