Some architectures will pretty-print a system call trap in the backtrace. Rather than printing the symbol, use the syscallname() function to pull the string from the sv_syscallnames array corresponding to the process. This simplifies the function somewhat. Mostly, this will result in dropping the "sys" prefix, e.g. "sys_exit" will now be printed simply as "exit". Make two minor tweaks to the function signature: use a u_int for the syscall number since this is a more correct type (see the 'code' member of struct syscall_args), and make the thread pointer the first argument. The latter is more natural and conventional. Suggested by: jrtc27 Reviewed by: jrtc27, markj, jhb MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D37200
500 lines
11 KiB
C
500 lines
11 KiB
C
/*-
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* SPDX-License-Identifier: MIT-CMU
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*
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* Mach Operating System
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* Copyright (c) 1991,1990 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* Author: David B. Golub, Carnegie Mellon University
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* Date: 7/90
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_kstack_pages.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/pcpu.h>
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#include <sys/proc.h>
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#include <sys/smp.h>
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#include <sys/sysent.h>
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#include <net/vnet.h>
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#include <ddb/ddb.h>
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#include <ddb/db_sym.h>
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#include <ddb/db_variables.h>
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#include "opt_ddb.h"
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/*
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* Multiple symbol tables
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*/
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#ifndef MAXNOSYMTABS
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#define MAXNOSYMTABS 3 /* mach, ux, emulator */
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#endif
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static db_symtab_t db_symtabs[MAXNOSYMTABS] = {{0,},};
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static int db_nsymtab = 0;
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static db_symtab_t *db_last_symtab; /* where last symbol was found */
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static c_db_sym_t db_lookup( const char *symstr);
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static char *db_qualify(c_db_sym_t sym, char *symtabname);
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static bool db_symbol_is_ambiguous(c_db_sym_t sym);
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static bool db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
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static int db_cpu = -1;
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#ifdef VIMAGE
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static void *db_vnet = NULL;
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#endif
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/*
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* Validate the CPU number used to interpret per-CPU variables so we can
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* avoid later confusion if an invalid CPU is requested.
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*/
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int
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db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
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{
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switch (op) {
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case DB_VAR_GET:
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*valuep = db_cpu;
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return (1);
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case DB_VAR_SET:
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if (*(int *)valuep < -1 || *(int *)valuep > mp_maxid) {
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db_printf("Invalid value: %d\n", *(int*)valuep);
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return (0);
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}
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db_cpu = *(int *)valuep;
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return (1);
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default:
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db_printf("db_var_db_cpu: unknown operation\n");
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return (0);
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}
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}
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/*
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* Read-only variable reporting the current CPU, which is what we use when
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* db_cpu is set to -1.
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*/
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int
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db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
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{
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switch (op) {
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case DB_VAR_GET:
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*valuep = curcpu;
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return (1);
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case DB_VAR_SET:
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db_printf("Read-only variable.\n");
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return (0);
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default:
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db_printf("db_var_curcpu: unknown operation\n");
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return (0);
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}
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}
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#ifdef VIMAGE
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/*
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* Validate the virtual network pointer used to interpret per-vnet global
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* variable expansion. Right now we don't do much here, really we should
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* walk the global vnet list to check it's an OK pointer.
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*/
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int
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db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
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{
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switch (op) {
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case DB_VAR_GET:
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*valuep = (db_expr_t)db_vnet;
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return (1);
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case DB_VAR_SET:
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db_vnet = *(void **)valuep;
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return (1);
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default:
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db_printf("db_var_db_vnet: unknown operation\n");
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return (0);
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}
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}
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/*
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* Read-only variable reporting the current vnet, which is what we use when
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* db_vnet is set to NULL.
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*/
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int
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db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
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{
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switch (op) {
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case DB_VAR_GET:
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*valuep = (db_expr_t)curvnet;
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return (1);
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case DB_VAR_SET:
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db_printf("Read-only variable.\n");
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return (0);
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default:
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db_printf("db_var_curvnet: unknown operation\n");
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return (0);
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}
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}
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#endif
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/*
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* Add symbol table, with given name, to list of symbol tables.
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*/
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void
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db_add_symbol_table(char *start, char *end, char *name, char *ref)
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{
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if (db_nsymtab >= MAXNOSYMTABS) {
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printf ("No slots left for %s symbol table", name);
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panic ("db_sym.c: db_add_symbol_table");
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}
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db_symtabs[db_nsymtab].start = start;
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db_symtabs[db_nsymtab].end = end;
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db_symtabs[db_nsymtab].name = name;
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db_symtabs[db_nsymtab].private = ref;
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db_nsymtab++;
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}
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/*
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* db_qualify("vm_map", "ux") returns "unix:vm_map".
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*
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* Note: return value points to static data whose content is
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* overwritten by each call... but in practice this seems okay.
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*/
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static char *
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db_qualify(c_db_sym_t sym, char *symtabname)
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{
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const char *symname;
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static char tmp[256];
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db_symbol_values(sym, &symname, 0);
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snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
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return tmp;
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}
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bool
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db_eqname(const char *src, const char *dst, int c)
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{
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if (!strcmp(src, dst))
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return (true);
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if (src[0] == c)
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return (!strcmp(src+1,dst));
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return (false);
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}
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bool
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db_value_of_name(const char *name, db_expr_t *valuep)
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{
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c_db_sym_t sym;
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sym = db_lookup(name);
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if (sym == C_DB_SYM_NULL)
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return (false);
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db_symbol_values(sym, &name, valuep);
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return (true);
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}
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bool
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db_value_of_name_pcpu(const char *name, db_expr_t *valuep)
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{
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static char tmp[256];
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db_expr_t value;
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c_db_sym_t sym;
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int cpu;
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if (db_cpu != -1)
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cpu = db_cpu;
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else
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cpu = curcpu;
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snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
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sym = db_lookup(tmp);
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if (sym == C_DB_SYM_NULL)
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return (false);
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db_symbol_values(sym, &name, &value);
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if (value < DPCPU_START || value >= DPCPU_STOP)
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return (false);
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*valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
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return (true);
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}
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bool
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db_value_of_name_vnet(const char *name, db_expr_t *valuep)
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{
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#ifdef VIMAGE
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static char tmp[256];
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db_expr_t value;
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c_db_sym_t sym;
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struct vnet *vnet;
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if (db_vnet != NULL)
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vnet = db_vnet;
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else
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vnet = curvnet;
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snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
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sym = db_lookup(tmp);
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if (sym == C_DB_SYM_NULL)
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return (false);
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db_symbol_values(sym, &name, &value);
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if (value < VNET_START || value >= VNET_STOP)
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return (false);
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*valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
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return (true);
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#else
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return (false);
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#endif
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}
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/*
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* Lookup a symbol.
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* If the symbol has a qualifier (e.g., ux:vm_map),
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* then only the specified symbol table will be searched;
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* otherwise, all symbol tables will be searched.
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*/
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static c_db_sym_t
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db_lookup(const char *symstr)
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{
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c_db_sym_t sp;
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int i;
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int symtab_start = 0;
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int symtab_end = db_nsymtab;
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const char *cp;
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/*
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* Look for, remove, and remember any symbol table specifier.
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*/
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for (cp = symstr; *cp; cp++) {
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if (*cp == ':') {
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for (i = 0; i < db_nsymtab; i++) {
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int n = strlen(db_symtabs[i].name);
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if (
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n == (cp - symstr) &&
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strncmp(symstr, db_symtabs[i].name, n) == 0
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) {
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symtab_start = i;
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symtab_end = i + 1;
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break;
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}
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}
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if (i == db_nsymtab) {
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db_error("invalid symbol table name");
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}
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symstr = cp+1;
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}
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}
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/*
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* Look in the specified set of symbol tables.
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* Return on first match.
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*/
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for (i = symtab_start; i < symtab_end; i++) {
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sp = X_db_lookup(&db_symtabs[i], symstr);
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if (sp) {
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db_last_symtab = &db_symtabs[i];
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return sp;
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}
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}
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return 0;
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}
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/*
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* If true, check across symbol tables for multiple occurrences
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* of a name. Might slow things down quite a bit.
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*/
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static volatile bool db_qualify_ambiguous_names = false;
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/*
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* Does this symbol name appear in more than one symbol table?
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* Used by db_symbol_values to decide whether to qualify a symbol.
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*/
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static bool
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db_symbol_is_ambiguous(c_db_sym_t sym)
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{
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const char *sym_name;
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int i;
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bool found_once = false;
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if (!db_qualify_ambiguous_names)
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return (false);
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db_symbol_values(sym, &sym_name, 0);
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for (i = 0; i < db_nsymtab; i++) {
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if (X_db_lookup(&db_symtabs[i], sym_name)) {
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if (found_once)
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return (true);
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found_once = true;
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}
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}
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return (false);
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}
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/*
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* Find the closest symbol to val, and return its name
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* and the difference between val and the symbol found.
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*/
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c_db_sym_t
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db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
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{
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unsigned int diff;
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size_t newdiff;
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int i;
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c_db_sym_t ret, sym;
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/*
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* The kernel will never map the first page, so any symbols in that
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* range cannot refer to addresses. Some third-party assembly files
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* define internal constants which appear in their symbol table.
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* Avoiding the lookup for those symbols avoids replacing small offsets
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* with those symbols during disassembly.
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*/
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if (val < PAGE_SIZE) {
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*offp = 0;
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return (C_DB_SYM_NULL);
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}
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ret = C_DB_SYM_NULL;
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newdiff = diff = val;
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for (i = 0; i < db_nsymtab; i++) {
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sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
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if ((uintmax_t)newdiff < (uintmax_t)diff) {
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db_last_symtab = &db_symtabs[i];
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diff = newdiff;
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ret = sym;
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}
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}
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*offp = diff;
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return ret;
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}
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/*
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* Return name and value of a symbol
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*/
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void
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db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep)
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{
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db_expr_t value;
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if (sym == DB_SYM_NULL) {
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*namep = NULL;
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return;
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}
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X_db_symbol_values(db_last_symtab, sym, namep, &value);
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if (db_symbol_is_ambiguous(sym))
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*namep = db_qualify(sym, db_last_symtab->name);
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if (valuep)
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*valuep = value;
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}
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/*
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* Print a the closest symbol to value
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*
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* After matching the symbol according to the given strategy
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* we print it in the name+offset format, provided the symbol's
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* value is close enough (eg smaller than db_maxoff).
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* We also attempt to print [filename:linenum] when applicable
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* (eg for procedure names).
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*
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* If we could not find a reasonable name+offset representation,
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* then we just print the value in hex. Small values might get
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* bogus symbol associations, e.g. 3 might get some absolute
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* value like _INCLUDE_VERSION or something, therefore we do
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* not accept symbols whose value is "small" (and use plain hex).
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*/
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db_expr_t db_maxoff = 0x10000;
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void
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db_printsym(db_expr_t off, db_strategy_t strategy)
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{
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db_expr_t d;
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char *filename;
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const char *name;
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int linenum;
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c_db_sym_t cursym;
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if (off < 0 && off >= -db_maxoff) {
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db_printf("%+#lr", (long)off);
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return;
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}
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cursym = db_search_symbol(off, strategy, &d);
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db_symbol_values(cursym, &name, NULL);
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if (name == NULL || d >= (db_addr_t)db_maxoff) {
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db_printf("%#lr", (unsigned long)off);
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return;
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}
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#ifdef DDB_NUMSYM
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db_printf("%#lr = %s", (unsigned long)off, name);
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#else
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db_printf("%s", name);
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#endif
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if (d)
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db_printf("+%+#lr", (long)d);
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if (strategy == DB_STGY_PROC) {
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if (db_line_at_pc(cursym, &filename, &linenum, off))
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db_printf(" [%s:%d]", filename, linenum);
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}
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}
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static bool
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db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc)
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{
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return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc));
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}
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bool
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db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames)
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{
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return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames));
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}
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void
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db_decode_syscall(struct thread *td, u_int number)
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{
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struct proc *p;
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db_printf(" (%u", number);
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p = (td != NULL) ? td->td_proc : NULL;
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if (p != NULL) {
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db_printf(", %s, %s", p->p_sysent->sv_name,
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syscallname(p, number));
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}
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db_printf(")");
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}
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