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 char 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 FICL_WORD *pInterp;
67
68 /*
69 * Shim for taking commands from BF and passing them out to 'standard'
70 * argv/argc command functions.
71 */
72 static void
bf_command(FICL_VM * vm)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 free(line);
142 /*
143 * If there was error during nested ficlExec(), we may no longer have
144 * valid environment to return. Throw all exceptions from here.
145 */
146 if (result != 0)
147 vmThrow(vm, result);
148 /* This is going to be thrown!!! */
149 stackPushINT(vm->pStack,result);
150 }
151
152 /*
153 * Replace a word definition (a builtin command) with another
154 * one that:
155 *
156 * - Throw error results instead of returning them on the stack
157 * - Pass a flag indicating whether the word was compiled or is
158 * being interpreted.
159 *
160 * There is one major problem with builtins that cannot be overcome
161 * in anyway, except by outlawing it. We want builtins to behave
162 * differently depending on whether they have been compiled or they
163 * are being interpreted. Notice that this is *not* the interpreter's
164 * current state. For example:
165 *
166 * : example ls ; immediate
167 * : problem example ; \ "ls" gets executed while compiling
168 * example \ "ls" gets executed while interpreting
169 *
170 * Notice that, though the current state is different in the two
171 * invocations of "example", in both cases "ls" has been
172 * *compiled in*, which is what we really want.
173 *
174 * The problem arises when you tick the builtin. For example:
175 *
176 * : example-1 ['] ls postpone literal ; immediate
177 * : example-2 example-1 execute ; immediate
178 * : problem example-2 ;
179 * example-2
180 *
181 * We have no way, when we get EXECUTEd, of knowing what our behavior
182 * should be. Thus, our only alternative is to "outlaw" this. See RFI
183 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
184 * problem, concerning compile semantics.
185 *
186 * The problem is compounded by the fact that "' builtin CATCH" is valid
187 * and desirable. The only solution is to create an intermediary word.
188 * For example:
189 *
190 * : my-ls ls ;
191 * : example ['] my-ls catch ;
192 *
193 * So, with the below implementation, here is a summary of the behavior
194 * of builtins:
195 *
196 * ls -l \ "interpret" behavior, ie,
197 * \ takes parameters from TIB
198 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
199 * \ takes parameters from the stack
200 * : ex-2 ['] ls catch ; immediate \ undefined behavior
201 * : ex-3 ['] ls catch ; \ undefined behavior
202 * ex-2 ex-3 \ "interpret" behavior,
203 * \ catch works
204 * : ex-4 ex-2 ; \ "compile" behavior,
205 * \ catch does not work
206 * : ex-5 ex-3 ; immediate \ same as ex-2
207 * : ex-6 ex-3 ; \ same as ex-3
208 * : ex-7 ['] ex-1 catch ; \ "compile" behavior,
209 * \ catch works
210 * : ex-8 postpone ls ; immediate \ same as ex-2
211 * : ex-9 postpone ls ; \ same as ex-3
212 *
213 * As the definition below is particularly tricky, and it's side effects
214 * must be well understood by those playing with it, I'll be heavy on
215 * the comments.
216 *
217 * (if you edit this definition, pay attention to trailing spaces after
218 * each word -- I warned you! :-) )
219 */
220 #define BUILTIN_CONSTRUCTOR \
221 ": builtin: " \
222 ">in @ " /* save the tib index pointer */ \
223 "' " /* get next word's xt */ \
224 "swap >in ! " /* point again to next word */ \
225 "create " /* create a new definition of the next word */ \
226 ", " /* save previous definition's xt */ \
227 "immediate " /* make the new definition an immediate word */ \
228 \
229 "does> " /* Now, the *new* definition will: */ \
230 "state @ if " /* if in compiling state: */ \
231 "1 postpone literal " /* pass 1 flag to indicate compile */ \
232 "@ compile, " /* compile in previous definition */ \
233 "postpone throw " /* throw stack-returned result */ \
234 "else " /* if in interpreting state: */ \
235 "0 swap " /* pass 0 flag to indicate interpret */ \
236 "@ execute " /* call previous definition */ \
237 "throw " /* throw stack-returned result */ \
238 "then ; "
239
240 /*
241 * Initialise the Forth interpreter, create all our commands as words.
242 */
243 void
bf_init(const char * rc)244 bf_init(const char *rc)
245 {
246 struct bootblk_command **cmdp;
247 char create_buf[41]; /* 31 characters-long builtins */
248 int fd;
249
250 bf_sys = ficlInitSystem(BF_DICTSIZE);
251 bf_vm = ficlNewVM(bf_sys);
252
253 /* Put all private definitions in a "builtins" vocabulary */
254 ficlExec(bf_vm, "vocabulary builtins also builtins definitions");
255
256 /* Builtin constructor word */
257 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);
258
259 /* make all commands appear as Forth words */
260 SET_FOREACH(cmdp, Xcommand_set) {
261 ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT);
262 ficlExec(bf_vm, "forth definitions builtins");
263 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
264 ficlExec(bf_vm, create_buf);
265 ficlExec(bf_vm, "builtins definitions");
266 }
267 ficlExec(bf_vm, "only forth definitions");
268
269 /* Export some version numbers so that code can detect the loader/host version */
270 ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version);
271 ficlSetEnv(bf_sys, "loader_version",
272 (bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));
273
274 pInterp = ficlLookup(bf_sys, "interpret");
275
276 /* try to load and run init file if present */
277 if (rc == NULL)
278 rc = "/boot/boot.4th";
279 if (*rc != '\0') {
280 fd = open(rc, O_RDONLY);
281 if (fd != -1) {
282 (void)ficlExecFD(bf_vm, fd);
283 close(fd);
284 }
285 }
286
287 /* Do this again, so that interpret can be redefined. */
288 pInterp = ficlLookup(bf_sys, "interpret");
289 }
290
291 /*
292 * Feed a line of user input to the Forth interpreter
293 */
294 int
bf_run(char * line)295 bf_run(char *line)
296 {
297 int result;
298
299 result = ficlExec(bf_vm, line);
300
301 DEBUG("ficlExec '%s' = %d", line, result);
302 switch (result) {
303 case VM_OUTOFTEXT:
304 case VM_ABORTQ:
305 case VM_QUIT:
306 case VM_ERREXIT:
307 break;
308 case VM_USEREXIT:
309 printf("No where to leave to!\n");
310 break;
311 case VM_ABORT:
312 printf("Aborted!\n");
313 break;
314 case BF_PARSE:
315 printf("Parse error!\n");
316 break;
317 default:
318 /* Hopefully, all other codes filled this buffer */
319 printf("%s\n", command_errmsg);
320 }
321
322 if (result == VM_USEREXIT)
323 panic("interpreter exit");
324 setenv("interpret", bf_vm->state ? "" : "OK", 1);
325
326 return result;
327 }
328