db_sym.c

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    1 /*-
    2  * Mach Operating System
    3  * Copyright (c) 1991,1990 Carnegie Mellon University
    4  * All Rights Reserved.
    5  *
    6  * Permission to use, copy, modify and distribute this software and its
    7  * documentation is hereby granted, provided that both the copyright
    8  * notice and this permission notice appear in all copies of the
    9  * software, derivative works or modified versions, and any portions
   10  * thereof, and that both notices appear in supporting documentation.
   11  *
   12  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
   13  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
   14  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   15  *
   16  * Carnegie Mellon requests users of this software to return to
   17  *
   18  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   19  *  School of Computer Science
   20  *  Carnegie Mellon University
   21  *  Pittsburgh PA 15213-3890
   22  *
   23  * any improvements or extensions that they make and grant Carnegie the
   24  * rights to redistribute these changes.
   25  */
   26 /*
   27  *      Author: David B. Golub, Carnegie Mellon University
   28  *      Date:   7/90
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD: releng/11.2/sys/ddb/db_sym.c 331643 2018-03-27 18:52:27Z dim $");
   33 
   34 #include "opt_kstack_pages.h"
   35 
   36 #include <sys/param.h>
   37 #include <sys/pcpu.h>
   38 #include <sys/smp.h>
   39 #include <sys/systm.h>
   40 
   41 #include <net/vnet.h>
   42 
   43 #include <ddb/ddb.h>
   44 #include <ddb/db_sym.h>
   45 #include <ddb/db_variables.h>
   46 
   47 #include <opt_ddb.h>
   48 
   49 /*
   50  * Multiple symbol tables
   51  */
   52 #ifndef MAXNOSYMTABS
   53 #define MAXNOSYMTABS    3       /* mach, ux, emulator */
   54 #endif
   55 
   56 static db_symtab_t      db_symtabs[MAXNOSYMTABS] = {{0,},};
   57 static int db_nsymtab = 0;
   58 
   59 static db_symtab_t      *db_last_symtab; /* where last symbol was found */
   60 
   61 static c_db_sym_t       db_lookup( const char *symstr);
   62 static char             *db_qualify(c_db_sym_t sym, char *symtabname);
   63 static bool             db_symbol_is_ambiguous(c_db_sym_t sym);
   64 static bool             db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
   65 
   66 static int db_cpu = -1;
   67 
   68 #ifdef VIMAGE
   69 static void *db_vnet = NULL;
   70 #endif
   71 
   72 /*
   73  * Validate the CPU number used to interpret per-CPU variables so we can
   74  * avoid later confusion if an invalid CPU is requested.
   75  */
   76 int
   77 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
   78 {
   79 
   80         switch (op) {
   81         case DB_VAR_GET:
   82                 *valuep = db_cpu;
   83                 return (1);
   84 
   85         case DB_VAR_SET:
   86                 if (*(int *)valuep < -1 || *(int *)valuep > mp_maxid) {
   87                         db_printf("Invalid value: %d\n", *(int*)valuep);
   88                         return (0);
   89                 }
   90                 db_cpu = *(int *)valuep;
   91                 return (1);
   92 
   93         default:
   94                 db_printf("db_var_db_cpu: unknown operation\n");
   95                 return (0);
   96         }
   97 }
   98 
   99 /*
  100  * Read-only variable reporting the current CPU, which is what we use when
  101  * db_cpu is set to -1.
  102  */
  103 int
  104 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
  105 {
  106 
  107         switch (op) {
  108         case DB_VAR_GET:
  109                 *valuep = curcpu;
  110                 return (1);
  111 
  112         case DB_VAR_SET:
  113                 db_printf("Read-only variable.\n");
  114                 return (0);
  115 
  116         default:
  117                 db_printf("db_var_curcpu: unknown operation\n");
  118                 return (0);
  119         }
  120 }
  121 
  122 #ifdef VIMAGE
  123 /*
  124  * Validate the virtual network pointer used to interpret per-vnet global
  125  * variable expansion.  Right now we don't do much here, really we should
  126  * walk the global vnet list to check it's an OK pointer.
  127  */
  128 int
  129 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
  130 {
  131 
  132         switch (op) {
  133         case DB_VAR_GET:
  134                 *valuep = (db_expr_t)db_vnet;
  135                 return (1);
  136 
  137         case DB_VAR_SET:
  138                 db_vnet = *(void **)valuep;
  139                 return (1);
  140 
  141         default:
  142                 db_printf("db_var_db_vnet: unknown operation\n");
  143                 return (0);
  144         }
  145 }
  146 
  147 /*
  148  * Read-only variable reporting the current vnet, which is what we use when
  149  * db_vnet is set to NULL.
  150  */
  151 int
  152 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
  153 {
  154 
  155         switch (op) {
  156         case DB_VAR_GET:
  157                 *valuep = (db_expr_t)curvnet;
  158                 return (1);
  159 
  160         case DB_VAR_SET:
  161                 db_printf("Read-only variable.\n");
  162                 return (0);
  163 
  164         default:
  165                 db_printf("db_var_curvnet: unknown operation\n");
  166                 return (0);
  167         }
  168 }
  169 #endif
  170 
  171 /*
  172  * Add symbol table, with given name, to list of symbol tables.
  173  */
  174 void
  175 db_add_symbol_table(char *start, char *end, char *name, char *ref)
  176 {
  177         if (db_nsymtab >= MAXNOSYMTABS) {
  178                 printf ("No slots left for %s symbol table", name);
  179                 panic ("db_sym.c: db_add_symbol_table");
  180         }
  181 
  182         db_symtabs[db_nsymtab].start = start;
  183         db_symtabs[db_nsymtab].end = end;
  184         db_symtabs[db_nsymtab].name = name;
  185         db_symtabs[db_nsymtab].private = ref;
  186         db_nsymtab++;
  187 }
  188 
  189 /*
  190  *  db_qualify("vm_map", "ux") returns "unix:vm_map".
  191  *
  192  *  Note: return value points to static data whose content is
  193  *  overwritten by each call... but in practice this seems okay.
  194  */
  195 static char *
  196 db_qualify(c_db_sym_t sym, char *symtabname)
  197 {
  198         const char      *symname;
  199         static char     tmp[256];
  200 
  201         db_symbol_values(sym, &symname, 0);
  202         snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
  203         return tmp;
  204 }
  205 
  206 
  207 bool
  208 db_eqname(const char *src, const char *dst, int c)
  209 {
  210         if (!strcmp(src, dst))
  211             return (true);
  212         if (src[0] == c)
  213             return (!strcmp(src+1,dst));
  214         return (false);
  215 }
  216 
  217 bool
  218 db_value_of_name(const char *name, db_expr_t *valuep)
  219 {
  220         c_db_sym_t      sym;
  221 
  222         sym = db_lookup(name);
  223         if (sym == C_DB_SYM_NULL)
  224             return (false);
  225         db_symbol_values(sym, &name, valuep);
  226         return (true);
  227 }
  228 
  229 bool
  230 db_value_of_name_pcpu(const char *name, db_expr_t *valuep)
  231 {
  232         static char     tmp[256];
  233         db_expr_t       value;
  234         c_db_sym_t      sym;
  235         int             cpu;
  236 
  237         if (db_cpu != -1)
  238                 cpu = db_cpu;
  239         else
  240                 cpu = curcpu;
  241         snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
  242         sym = db_lookup(tmp);
  243         if (sym == C_DB_SYM_NULL)
  244                 return (false);
  245         db_symbol_values(sym, &name, &value);
  246         if (value < DPCPU_START || value >= DPCPU_STOP)
  247                 return (false);
  248         *valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
  249         return (true);
  250 }
  251 
  252 bool
  253 db_value_of_name_vnet(const char *name, db_expr_t *valuep)
  254 {
  255 #ifdef VIMAGE
  256         static char     tmp[256];
  257         db_expr_t       value;
  258         c_db_sym_t      sym;
  259         struct vnet     *vnet;
  260 
  261         if (db_vnet != NULL)
  262                 vnet = db_vnet;
  263         else
  264                 vnet = curvnet;
  265         snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
  266         sym = db_lookup(tmp);
  267         if (sym == C_DB_SYM_NULL)
  268                 return (false);
  269         db_symbol_values(sym, &name, &value);
  270         if (value < VNET_START || value >= VNET_STOP)
  271                 return (false);
  272         *valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
  273         return (true);
  274 #else
  275         return (false);
  276 #endif
  277 }
  278 
  279 /*
  280  * Lookup a symbol.
  281  * If the symbol has a qualifier (e.g., ux:vm_map),
  282  * then only the specified symbol table will be searched;
  283  * otherwise, all symbol tables will be searched.
  284  */
  285 static c_db_sym_t
  286 db_lookup(const char *symstr)
  287 {
  288         c_db_sym_t sp;
  289         int i;
  290         int symtab_start = 0;
  291         int symtab_end = db_nsymtab;
  292         const char *cp;
  293 
  294         /*
  295          * Look for, remove, and remember any symbol table specifier.
  296          */
  297         for (cp = symstr; *cp; cp++) {
  298                 if (*cp == ':') {
  299                         for (i = 0; i < db_nsymtab; i++) {
  300                                 int n = strlen(db_symtabs[i].name);
  301 
  302                                 if (
  303                                     n == (cp - symstr) &&
  304                                     strncmp(symstr, db_symtabs[i].name, n) == 0
  305                                 ) {
  306                                         symtab_start = i;
  307                                         symtab_end = i + 1;
  308                                         break;
  309                                 }
  310                         }
  311                         if (i == db_nsymtab) {
  312                                 db_error("invalid symbol table name");
  313                         }
  314                         symstr = cp+1;
  315                 }
  316         }
  317 
  318         /*
  319          * Look in the specified set of symbol tables.
  320          * Return on first match.
  321          */
  322         for (i = symtab_start; i < symtab_end; i++) {
  323                 sp = X_db_lookup(&db_symtabs[i], symstr);
  324                 if (sp) {
  325                         db_last_symtab = &db_symtabs[i];
  326                         return sp;
  327                 }
  328         }
  329         return 0;
  330 }
  331 
  332 /*
  333  * If true, check across symbol tables for multiple occurrences
  334  * of a name.  Might slow things down quite a bit.
  335  */
  336 static volatile bool db_qualify_ambiguous_names = false;
  337 
  338 /*
  339  * Does this symbol name appear in more than one symbol table?
  340  * Used by db_symbol_values to decide whether to qualify a symbol.
  341  */
  342 static bool
  343 db_symbol_is_ambiguous(c_db_sym_t sym)
  344 {
  345         const char      *sym_name;
  346         int             i;
  347         bool            found_once = false;
  348 
  349         if (!db_qualify_ambiguous_names)
  350                 return (false);
  351 
  352         db_symbol_values(sym, &sym_name, 0);
  353         for (i = 0; i < db_nsymtab; i++) {
  354                 if (X_db_lookup(&db_symtabs[i], sym_name)) {
  355                         if (found_once)
  356                                 return (true);
  357                         found_once = true;
  358                 }
  359         }
  360         return (false);
  361 }
  362 
  363 /*
  364  * Find the closest symbol to val, and return its name
  365  * and the difference between val and the symbol found.
  366  */
  367 c_db_sym_t
  368 db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
  369 {
  370         unsigned int    diff;
  371         size_t          newdiff;
  372         int             i;
  373         c_db_sym_t      ret = C_DB_SYM_NULL, sym;
  374 
  375         newdiff = diff = ~0;
  376         for (i = 0; i < db_nsymtab; i++) {
  377             sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
  378             if (newdiff < diff) {
  379                 db_last_symtab = &db_symtabs[i];
  380                 diff = newdiff;
  381                 ret = sym;
  382             }
  383         }
  384         *offp = diff;
  385         return ret;
  386 }
  387 
  388 /*
  389  * Return name and value of a symbol
  390  */
  391 void
  392 db_symbol_values(c_db_sym_t sym, const char **namep, db_expr_t *valuep)
  393 {
  394         db_expr_t       value;
  395 
  396         if (sym == DB_SYM_NULL) {
  397                 *namep = NULL;
  398                 return;
  399         }
  400 
  401         X_db_symbol_values(db_last_symtab, sym, namep, &value);
  402 
  403         if (db_symbol_is_ambiguous(sym))
  404                 *namep = db_qualify(sym, db_last_symtab->name);
  405         if (valuep)
  406                 *valuep = value;
  407 }
  408 
  409 
  410 /*
  411  * Print a the closest symbol to value
  412  *
  413  * After matching the symbol according to the given strategy
  414  * we print it in the name+offset format, provided the symbol's
  415  * value is close enough (eg smaller than db_maxoff).
  416  * We also attempt to print [filename:linenum] when applicable
  417  * (eg for procedure names).
  418  *
  419  * If we could not find a reasonable name+offset representation,
  420  * then we just print the value in hex.  Small values might get
  421  * bogus symbol associations, e.g. 3 might get some absolute
  422  * value like _INCLUDE_VERSION or something, therefore we do
  423  * not accept symbols whose value is "small" (and use plain hex).
  424  */
  425 
  426 db_expr_t       db_maxoff = 0x10000;
  427 
  428 void
  429 db_printsym(db_expr_t off, db_strategy_t strategy)
  430 {
  431         db_expr_t       d;
  432         char            *filename;
  433         const char      *name;
  434         db_expr_t       value;
  435         int             linenum;
  436         c_db_sym_t      cursym;
  437 
  438         cursym = db_search_symbol(off, strategy, &d);
  439         db_symbol_values(cursym, &name, &value);
  440         if (name == NULL)
  441                 value = off;
  442         if (value >= DB_SMALL_VALUE_MIN && value <= DB_SMALL_VALUE_MAX) {
  443                 db_printf("%+#lr", (long)off);
  444                 return;
  445         }
  446         if (name == NULL || d >= (unsigned long)db_maxoff) {
  447                 db_printf("%#lr", (unsigned long)off);
  448                 return;
  449         }
  450 #ifdef DDB_NUMSYM
  451         db_printf("%#lr = %s", (unsigned long)off, name);
  452 #else
  453         db_printf("%s", name);
  454 #endif
  455         if (d)
  456                 db_printf("+%+#lr", (long)d);
  457         if (strategy == DB_STGY_PROC) {
  458                 if (db_line_at_pc(cursym, &filename, &linenum, off))
  459                         db_printf(" [%s:%d]", filename, linenum);
  460         }
  461 }
  462 
  463 static bool
  464 db_line_at_pc(c_db_sym_t sym, char **filename, int *linenum, db_expr_t pc)
  465 {
  466         return (X_db_line_at_pc(db_last_symtab, sym, filename, linenum, pc));
  467 }
  468 
  469 bool
  470 db_sym_numargs(c_db_sym_t sym, int *nargp, char **argnames)
  471 {
  472         return (X_db_sym_numargs(db_last_symtab, sym, nargp, argnames));
  473 }
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FreeBSD/Linux Kernel Cross Reference sys/ddb/db_sym.c

FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_sym.c
