1/*-
2 * SPDX-License-Identifier: MIT-CMU
3 *
4 * Mach Operating System
5 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * All Rights Reserved.
7 *
8 * Permission to use, copy, modify and distribute this software and its
9 * documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
15 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
16 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
21 *  School of Computer Science
22 *  Carnegie Mellon University
23 *  Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28/*
29 * 	Author: David B. Golub, Carnegie Mellon University
30 *	Date:	7/90
31 */
32
33#include <sys/cdefs.h>
34#include "opt_kstack_pages.h"
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/pcpu.h>
39#include <sys/proc.h>
40#include <sys/smp.h>
41#include <sys/sysent.h>
42
43#include <net/vnet.h>
44
45#include <ddb/ddb.h>
46#include <ddb/db_sym.h>
47#include <ddb/db_variables.h>
48
49#include "opt_ddb.h"
50
51/*
52 * Multiple symbol tables
53 */
54#ifndef MAXNOSYMTABS
55#define	MAXNOSYMTABS	3	/* mach, ux, emulator */
56#endif
57
58static db_symtab_t	db_symtabs[MAXNOSYMTABS] = {{0,},};
59static int db_nsymtab = 0;
60
61static db_symtab_t	*db_last_symtab; /* where last symbol was found */
62
63static c_db_sym_t	db_lookup( const char *symstr);
64static char		*db_qualify(c_db_sym_t sym, char *symtabname);
65static bool		db_symbol_is_ambiguous(c_db_sym_t sym);
66static bool		db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
67
68static int db_cpu = -1;
69
70#ifdef VIMAGE
71static void *db_vnet = NULL;
72#endif
73
74/*
75 * Validate the CPU number used to interpret per-CPU variables so we can
76 * avoid later confusion if an invalid CPU is requested.
77 */
78int
79db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
80{
81
82	switch (op) {
83	case DB_VAR_GET:
84		*valuep = db_cpu;
85		return (1);
86
87	case DB_VAR_SET:
88		if (*(int *)valuep < -1 || *(int *)valuep > mp_maxid) {
89			db_printf("Invalid value: %d\n", *(int*)valuep);
90			return (0);
91		}
92		db_cpu = *(int *)valuep;
93		return (1);
94
95	default:
96		db_printf("db_var_db_cpu: unknown operation\n");
97		return (0);
98	}
99}
100
101/*
102 * Read-only variable reporting the current CPU, which is what we use when
103 * db_cpu is set to -1.
104 */
105int
106db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
107{
108
109	switch (op) {
110	case DB_VAR_GET:
111		*valuep = curcpu;
112		return (1);
113
114	case DB_VAR_SET:
115		db_printf("Read-only variable.\n");
116		return (0);
117
118	default:
119		db_printf("db_var_curcpu: unknown operation\n");
120		return (0);
121	}
122}
123
124#ifdef VIMAGE
125/*
126 * Validate the virtual network pointer used to interpret per-vnet global
127 * variable expansion.  Right now we don't do much here, really we should
128 * walk the global vnet list to check it's an OK pointer.
129 */
130int
131db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
132{
133
134	switch (op) {
135	case DB_VAR_GET:
136		*valuep = (db_expr_t)db_vnet;
137		return (1);
138
139	case DB_VAR_SET:
140		db_vnet = *(void **)valuep;
141		return (1);
142
143	default:
144		db_printf("db_var_db_vnet: unknown operation\n");
145		return (0);
146	}
147}
148
149/*
150 * Read-only variable reporting the current vnet, which is what we use when
151 * db_vnet is set to NULL.
152 */
153int
154db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
155{
156
157	switch (op) {
158	case DB_VAR_GET:
159		*valuep = (db_expr_t)curvnet;
160		return (1);
161
162	case DB_VAR_SET:
163		db_printf("Read-only variable.\n");
164		return (0);
165
166	default:
167		db_printf("db_var_curvnet: unknown operation\n");
168		return (0);
169	}
170}
171#endif
172
173/*
174 * Add symbol table, with given name, to list of symbol tables.
175 */
176void
177db_add_symbol_table(char *start, char *end, char *name, char *ref)
178{
179	if (db_nsymtab >= MAXNOSYMTABS) {
180		printf ("No slots left for %s symbol table", name);
181		panic ("db_sym.c: db_add_symbol_table");
182	}
183
184	db_symtabs[db_nsymtab].start = start;
185	db_symtabs[db_nsymtab].end = end;
186	db_symtabs[db_nsymtab].name = name;
187	db_symtabs[db_nsymtab].private = ref;
188	db_nsymtab++;
189}
190
191/*
192 *  db_qualify("vm_map", "ux") returns "unix:vm_map".
193 *
194 *  Note: return value points to static data whose content is
195 *  overwritten by each call... but in practice this seems okay.
196 */
197static char *
198db_qualify(c_db_sym_t sym, char *symtabname)
199{
200	const char	*symname;
201	static char     tmp[256];
202
203	db_symbol_values(sym, &symname, 0);
204	snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
205	return tmp;
206}
207
208bool
209db_eqname(const char *src, const char *dst, int c)
210{
211	if (!strcmp(src, dst))
212	    return (true);
213	if (src[0] == c)
214	    return (!strcmp(src+1,dst));
215	return (false);
216}
217
218bool
219db_value_of_name(const char *name, db_expr_t *valuep)
220{
221	c_db_sym_t	sym;
222
223	sym = db_lookup(name);
224	if (sym == C_DB_SYM_NULL)
225	    return (false);
226	db_symbol_values(sym, &name, valuep);
227	return (true);
228}
229
230bool
231db_value_of_name_pcpu(const char *name, db_expr_t *valuep)
232{
233	static char     tmp[256];
234	db_expr_t	value;
235	c_db_sym_t	sym;
236	int		cpu;
237
238	if (db_cpu != -1)
239		cpu = db_cpu;
240	else
241		cpu = curcpu;
242	snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
243	sym = db_lookup(tmp);
244	if (sym == C_DB_SYM_NULL)
245		return (false);
246	db_symbol_values(sym, &name, &value);
247	if (value < DPCPU_START || value >= DPCPU_STOP)
248		return (false);
249	*valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
250	return (true);
251}
252
253bool
254db_value_of_name_vnet(const char *name, db_expr_t *valuep)
255{
256#ifdef VIMAGE
257	static char     tmp[256];
258	db_expr_t	value;
259	c_db_sym_t	sym;
260	struct vnet	*vnet;
261
262	if (db_vnet != NULL)
263		vnet = db_vnet;
264	else
265		vnet = curvnet;
266	snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
267	sym = db_lookup(tmp);
268	if (sym == C_DB_SYM_NULL)
269		return (false);
270	db_symbol_values(sym, &name, &value);
271	if (value < VNET_START || value >= VNET_STOP)
272		return (false);
273	*valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
274	return (true);
275#else
276	return (false);
277#endif
278}
279
280/*
281 * Lookup a symbol.
282 * If the symbol has a qualifier (e.g., ux:vm_map),
283 * then only the specified symbol table will be searched;
284 * otherwise, all symbol tables will be searched.
285 */
286static c_db_sym_t
287db_lookup(const char *symstr)
288{
289	c_db_sym_t sp;
290	int i;
291	int symtab_start = 0;
292	int symtab_end = db_nsymtab;
293	const char *cp;
294
295	/*
296	 * Look for, remove, and remember any symbol table specifier.
297	 */
298	for (cp = symstr; *cp; cp++) {
299		if (*cp == ':') {
300			for (i = 0; i < db_nsymtab; i++) {
301				int n = strlen(db_symtabs[i].name);
302
303				if (
304				    n == (cp - symstr) &&
305				    strncmp(symstr, db_symtabs[i].name, n) == 0
306				) {
307					symtab_start = i;
308					symtab_end = i + 1;
309					break;
310				}
311			}
312			if (i == db_nsymtab) {
313				db_error("invalid symbol table name");
314			}
315			symstr = cp+1;
316		}
317	}
318
319	/*
320	 * Look in the specified set of symbol tables.
321	 * Return on first match.
322	 */
323	for (i = symtab_start; i < symtab_end; i++) {
324		sp = X_db_lookup(&db_symtabs[i], symstr);
325		if (sp) {
326			db_last_symtab = &db_symtabs[i];
327			return sp;
328		}
329	}
330	return 0;
331}
332
333/*
334 * If true, check across symbol tables for multiple occurrences
335 * of a name.  Might slow things down quite a bit.
336 */
337static volatile bool db_qualify_ambiguous_names = false;
338
339/*
340 * Does this symbol name appear in more than one symbol table?
341 * Used by db_symbol_values to decide whether to qualify a symbol.
342 */
343static bool
344db_symbol_is_ambiguous(c_db_sym_t sym)
345{
346	const char	*sym_name;
347	int		i;
348	bool		found_once = false;
349
350	if (!db_qualify_ambiguous_names)
351		return (false);
352
353	db_symbol_values(sym, &sym_name, 0);
354	for (i = 0; i < db_nsymtab; i++) {
355		if (X_db_lookup(&db_symtabs[i], sym_name)) {
356			if (found_once)
357				return (true);
358			found_once = true;
359		}
360	}
361	return (false);
362}
363
364/*
365 * Find the closest symbol to val, and return its name
366 * and the difference between val and the symbol found.
367 */
368c_db_sym_t
369db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
370{
371	unsigned int	diff;
372	size_t		newdiff;
373	int		i;
374	c_db_sym_t	ret, sym;
375
376	/*
377	 * The kernel will never map the first page, so any symbols in that
378	 * range cannot refer to addresses.  Some third-party assembly files
379	 * define internal constants which appear in their symbol table.
380	 * Avoiding the lookup for those symbols avoids replacing small offsets
381	 * with those symbols during disassembly.
382	 */
383	if (val < PAGE_SIZE) {
384		*offp = 0;
385		return (C_DB_SYM_NULL);
386	}
387
388	ret = C_DB_SYM_NULL;
389	newdiff = diff = val;
390	for (i = 0; i < db_nsymtab; i++) {
391	    sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
392	    if ((uintmax_t)newdiff < (uintmax_t)diff) {
393		db_last_symtab = &db_symtabs[i];
394		diff = newdiff;
395		ret = sym;
396	    }
397	}
398	*offp = diff;
399	return ret;
400}
401
402/*
403 * Return name and value of a symbol
404 */
405void
406db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep)
407{
408	db_expr_t	value;
409
410	if (sym == DB_SYM_NULL) {
411		*namep = NULL;
412		return;
413	}
414
415	X_db_symbol_values(db_last_symtab, sym, namep, &value);
416
417	if (db_symbol_is_ambiguous(sym))
418		*namep = db_qualify(sym, db_last_symtab->name);
419	if (valuep)
420		*valuep = value;
421}
422
423/*
424 * Print a the closest symbol to value
425 *
426 * After matching the symbol according to the given strategy
427 * we print it in the name+offset format, provided the symbol's
428 * value is close enough (eg smaller than db_maxoff).
429 * We also attempt to print [filename:linenum] when applicable
430 * (eg for procedure names).
431 *
432 * If we could not find a reasonable name+offset representation,
433 * then we just print the value in hex.  Small values might get
434 * bogus symbol associations, e.g. 3 might get some absolute
435 * value like _INCLUDE_VERSION or something, therefore we do
436 * not accept symbols whose value is "small" (and use plain hex).
437 */
438
439db_expr_t	db_maxoff = 0x10000;
440
441void
442db_printsym(db_expr_t off, db_strategy_t strategy)
443{
444	db_expr_t	d;
445	char 		*filename;
446	const char	*name;
447	int 		linenum;
448	c_db_sym_t	cursym;
449
450	if (off < 0 && off >= -db_maxoff) {
451		db_printf("%+#lr", (long)off);
452		return;
453	}
454	cursym = db_search_symbol(off, strategy, &d);
455	db_symbol_values(cursym, &name, NULL);
456	if (name == NULL || d >= (db_addr_t)db_maxoff) {
457		db_printf("%#lr", (unsigned long)off);
458		return;
459	}
460#ifdef DDB_NUMSYM
461	db_printf("%#lr = %s", (unsigned long)off, name);
462#else
463	db_printf("%s", name);
464#endif
465	if (d)
466		db_printf("+%+#lr", (long)d);
467	if (strategy == DB_STGY_PROC) {
468		if (db_line_at_pc(cursym, &filename, &linenum, off))
469			db_printf(" [%s:%d]", filename, linenum);
470	}
471}
472
473static bool
474db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc)
475{
476	return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc));
477}
478
479bool
480db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames)
481{
482	return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames));
483}
484
485void
486db_decode_syscall(struct thread *td, u_int number)
487{
488	struct proc *p;
489
490	db_printf(" (%u", number);
491	p = (td != NULL) ? td->td_proc : NULL;
492	if (p != NULL) {
493		db_printf(", %s, %s", p->p_sysent->sv_name,
494		    syscallname(p, number));
495	}
496	db_printf(")");
497}
498