/*      $NetBSD: db_sym.c,v 1.71 2022/08/30 22:38:01 riastradh Exp $    */

/*
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_sym.c,v 1.71 2022/08/30 22:38:01 riastradh Exp $");

#ifdef _KERNEL_OPT
#include "opt_ddbparam.h"
#endif

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/ksyms.h>
#include <sys/pserialize.h>

#include <ddb/ddb.h>

static void             db_symsplit(char *, char **, char **);


#ifndef _KERNEL
#define TBLNAME "netbsd"

#define use_ksyms 0

const db_symformat_t *db_symformat;
static db_forall_func_t db_sift;
extern db_symformat_t db_symformat_elf;
#endif


/*
 * Initialize the kernel debugger by initializing the master symbol
 * table.  Note that if initializing the master symbol table fails,
 * no other symbol tables can be loaded.
 */
void
ddb_init(int symsize, void *vss, void *vse)
{
#ifdef _KERNEL
        ksyms_addsyms_elf(symsize, vss, vse);   /* Will complain if necessary */
#else   /* _KERNEL */
        db_symformat = &db_symformat_elf;
        if ((*db_symformat->sym_init)(symsize, vss, vse, TBLNAME) != true)
                printf("sym_init failed");
#endif  /* _KERNEL */
}

bool
db_eqname(const char *src, const char *dst, int c)
{

        if (!strcmp(src, dst))
                return (true);
        if (src[0] == c)
                return (!strcmp(src+1,dst));
        return (false);
}

bool
db_value_of_name(const char *name, db_expr_t *valuep)
{
        char symbol[128];
        char *mod, *sym;
#ifdef _KERNEL
        unsigned long uval;
        long val;
#endif

#ifndef _KERNEL
        if (!use_ksyms) {
                db_sym_t ssym;

                /*
                 * Cannot load symtabs in a.out kernels, so the ':'
                 * style of selecting modules is irrelevant.
                 */
                ssym = (*db_symformat->sym_lookup)(NULL, name);
                if (ssym == DB_SYM_NULL)
                        return (false);
                db_symbol_values(ssym, &name, valuep);
                return (true);
        }
#endif

        (void)strlcpy(symbol, name, sizeof(symbol));
        db_symsplit(symbol, &mod, &sym);
#ifdef _KERNEL
        if (ksyms_getval_unlocked(mod, sym, NULL, &uval, KSYMS_EXTERN) == 0) {
                val = (long) uval;
                *valuep = (db_expr_t)val;
                return true;
        }
        if (ksyms_getval_unlocked(mod, sym, NULL, &uval, KSYMS_ANY) == 0) {
                val = (long) uval;
                *valuep = (db_expr_t)val;
                return true;
        }
#endif
        return false;
}

#ifndef _KERNEL
/* Private structure for passing args to db_sift() from db_sifting(). */
struct db_sift_args {
        char    *symstr;
        int     mode;
};

/*
 * Does the work of db_sifting(), called once for each
 * symbol via db_forall(), prints out symbols matching
 * criteria.
 */
static void
db_sift(db_symtab_t *stab, db_sym_t sym, char *name,
    char *suffix, int prefix, void *arg)
{
        char c, sc;
        char *find, *p;
        size_t len;
        struct db_sift_args *dsa;

        dsa = (struct db_sift_args*)arg;

        find = dsa->symstr;     /* String we're looking for. */
        p = name;               /* String we're searching within. */

        /* Matching algorithm cribbed from strstr(), which is not
           in the kernel. */
        if ((c = *find++) != 0) {
                len = strlen(find);
                do {
                        do {
                                if ((sc = *p++) == 0)
                                        return;
                        } while (sc != c);
                } while (strncmp(p, find, len) != 0);
        }
        if (dsa->mode=='F')     /* ala ls -F */
                db_printf("%s%s ", name, suffix);
        else
                db_printf("%s ", name);
}
#endif

/*
 * "Sift" for a partial symbol.
 * Named for the Sun OpenPROM command ("sifting").
 * If the symbol has a qualifier (e.g., ux:vm_map),
 * then only the specified symbol table will be searched;
 * otherwise, all symbol tables will be searched..
 *
 * "mode" is how-to-display, set from modifiers.
 */
void
db_sifting(char *symstr, int mode)
{
#ifdef _KERNEL
        char *mod, *sym;
#endif

#ifndef _KERNEL
        struct db_sift_args dsa;

        if (!use_ksyms) {
                dsa.symstr = symstr;
                dsa.mode = mode;
                (*db_symformat->sym_forall)(NULL, db_sift, &dsa);
                db_printf("\n");
                return;
        }
#endif

#ifdef _KERNEL
        db_symsplit(symstr, &mod, &sym);
        if (ksyms_sift(mod, sym, mode) == ENODEV)
                db_error("invalid symbol table name");
#endif
}

/*
 * Find the closest symbol to val, and return its name
 * and the difference between val and the symbol found.
 */
db_sym_t
db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
{
        unsigned int diff;
        db_sym_t ret = DB_SYM_NULL;
#ifdef _KERNEL
        unsigned long naddr;
        const char *mod;
        const char *sym;
#endif

#ifndef _KERNEL
        if (!use_ksyms) {
                db_expr_t newdiff;
                db_sym_t ssym;

                diff = ~0u;
                newdiff = ~0;
                ssym = (*db_symformat->sym_search)
                    (NULL, val, strategy, &newdiff);
                if ((unsigned int) newdiff < diff) {
                        diff = newdiff;
                        ret = ssym;
                }
                *offp = diff;
                return ret;
        }
#endif

#ifdef _KERNEL
        if (ksyms_getname(&mod, &sym, (vaddr_t)val, strategy) == 0) {
                (void)ksyms_getval_unlocked(mod, sym, NULL, &naddr, KSYMS_ANY);
                diff = val - (db_addr_t)naddr;
                ret = (db_sym_t)naddr;
        } else
#endif
                diff = 0;
        *offp = diff;
        return ret;
}

/*
 * Return name and value of a symbol
 */
void
db_symbol_values(db_sym_t sym, const char **namep, db_expr_t *valuep)
{
#ifdef _KERNEL
        const char *mod;
#endif

        if (sym == DB_SYM_NULL) {
                *namep = 0;
                return;
        }

#ifndef _KERNEL
        if (!use_ksyms) {
                db_expr_t value;

                (*db_symformat->sym_value)(NULL, sym, namep, &value);
                if (valuep)
                        *valuep = value;
                return;
        }
#endif

#ifdef _KERNEL
        if (ksyms_getname(&mod, namep, (vaddr_t)sym,
            KSYMS_ANY|KSYMS_EXACT) == 0) {
                if (valuep)
                        *valuep = sym;
        } else
#endif
                *namep = NULL;
}


/*
 * Print a the closest symbol to value
 *
 * After matching the symbol according to the given strategy
 * we print it in the name+offset format, provided the symbol's
 * value is close enough (eg smaller than db_maxoff).
 * We also attempt to print [filename:linenum] when applicable
 * (eg for procedure names).
 *
 * If we could not find a reasonable name+offset representation,
 * then we just print the value in hex.  Small values might get
 * bogus symbol associations, e.g. 3 might get some absolute
 * value like _INCLUDE_VERSION or something, therefore we do
 * not accept symbols whose value is zero (and use plain hex).
 */
unsigned int    db_maxoff = 0x100000;

void
db_symstr(char *buf, size_t buflen, db_expr_t off, db_strategy_t strategy)
{
        const char  *name;
#ifdef _KERNEL
        const char *mod;
        unsigned long val;
#endif

#ifndef _KERNEL
        if (!use_ksyms) {
                db_expr_t       d;
                char            *filename;
                db_expr_t       value;
                int             linenum;
                db_sym_t        cursym;

                cursym = db_search_symbol(off, strategy, &d);
                db_symbol_values(cursym, &name, &value);
                if (name != NULL && ((unsigned int)d < db_maxoff) &&
                    value != 0) {
                        strlcpy(buf, name, buflen);
                        if (d) {
                                strlcat(buf, "+", buflen);
                                db_format_radix(buf + strlen(buf), 24, d, true);
                        }
                        if (strategy == DB_STGY_PROC) {
                                if ((*db_symformat->sym_line_at_pc)
                                    (NULL, cursym, &filename, &linenum, off)) {
                                        size_t len = strlen(buf);
                                        snprintf(buf + len, buflen - len,
                                            " [%s:%d]", filename, linenum);
                                }
                        }
                        return;
                }
                strlcpy(buf, db_num_to_str(off), buflen);
                return;
        }
#endif
#ifdef _KERNEL
        const int s = pserialize_read_enter();
        if (ksyms_getname(&mod, &name, (vaddr_t)off,
            strategy|KSYMS_CLOSEST) == 0) {
                (void)ksyms_getval_unlocked(mod, name, NULL, &val, KSYMS_ANY);
                if (strategy & KSYMS_PROC && val == off) {
                        if (ksyms_getname(&mod, &name, (vaddr_t)off - 1,
                                          strategy|KSYMS_CLOSEST) != 0)
                                goto hex_fallback;
                        (void)ksyms_getval_unlocked(mod, name, NULL, &val, KSYMS_ANY);
                }
                if (((off - val) < db_maxoff) && val) {
                        snprintf(buf, buflen, "%s:%s", mod, name);
                        if (off - val) {
                                strlcat(buf, "+", buflen);
                                db_format_radix(buf+strlen(buf),
                                    24, off - val, true);
                        }
#ifdef notyet
                        if (strategy & KSYMS_PROC) {
                                if (ksyms_fmaddr(off, &filename, &linenum) == 0)
                                        snprintf(buf + strlen(buf),
                                            buflen - strlen(buf),
                                            " [%s:%d]", filename, linenum);
                        }
#endif
                        goto out;
                }
        }
hex_fallback:
        db_num_to_strbuf(off, buf, buflen);
out:    pserialize_read_exit(s);
#endif
}

void
db_printsym(db_expr_t off, db_strategy_t strategy,
    void (*pr)(const char *, ...))
{
        const char  *name;
#ifdef _KERNEL
        const char *mod;
        unsigned long uval;
        long val;
#endif
#ifdef notyet
        char *filename;
        int  linenum;
#endif

#ifndef _KERNEL
        if (!use_ksyms) {
                db_expr_t       d;
                char            *filename;
                db_expr_t       value;
                int             linenum;
                db_sym_t        cursym;

                cursym = db_search_symbol(off, strategy, &d);
                db_symbol_values(cursym, &name, &value);
                if (name != NULL && ((unsigned int)d < db_maxoff) &&
                    value != 0) {
                        (*pr)("%s", name);
                        if (d) {
                                char tbuf[24];

                                db_format_radix(tbuf, 24, d, true);
                                (*pr)("+%s", tbuf);
                        }
                        if (strategy == DB_STGY_PROC) {
                                if ((*db_symformat->sym_line_at_pc)
                                    (NULL, cursym, &filename, &linenum, off))
                                        (*pr)(" [%s:%d]", filename, linenum);
                        }
                        return;
                }
                (*pr)("%s", db_num_to_str(off));
                return;
        }
#endif
#ifdef _KERNEL
        if (ksyms_getname(&mod, &name, (vaddr_t)off,
            strategy|KSYMS_CLOSEST) == 0) {
                (void)ksyms_getval_unlocked(mod, name, NULL, &uval, KSYMS_ANY);
                if (strategy & KSYMS_PROC && uval == off) {
                        if (ksyms_getname(&mod, &name, (vaddr_t)off - 1,
                                          strategy|KSYMS_CLOSEST) != 0)
                                goto out;
                        (void)ksyms_getval_unlocked(mod, name, NULL, &uval, KSYMS_ANY);
                }
                val = (long) uval;
                if (((off - val) < db_maxoff) && val) {
                        (*pr)("%s:%s", mod, name);
                        if (off - val) {
                                char tbuf[24];

                                db_format_radix(tbuf, 24, off - val, true);
                                (*pr)("+%s", tbuf);
                        }
#ifdef notyet
                        if (strategy & KSYMS_PROC) {
                                if (ksyms_fmaddr(off, &filename, &linenum) == 0)
                                        (*pr)(" [%s:%d]", filename, linenum);
                        }
#endif
                        return;
                }
        }
 out:;
#endif
        (*pr)("%s", db_num_to_str(off));
        return;
}

/*
 * Splits a string in the form "mod:sym" to two strings.
 */
static void
db_symsplit(char *str, char **mod, char **sym)
{
        char *cp;

        if ((cp = strchr(str, ':')) != NULL) {
                *cp++ = '\0';
                *mod = str;
                *sym = cp;
        } else {
                *mod = NULL;
                *sym = str;
        }
}

bool
db_sym_numargs(db_sym_t cursym, int *nargp, char **argnamep)
{
#ifndef _KERNEL
        if (!use_ksyms)
                return ((*db_symformat->sym_numargs)(NULL, cursym, nargp,
                    argnamep));
#endif
        return (false);
}