The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/ddb/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/10.4/sys/ddb/db_sym.c 273265 2014-10-18 19:22:59Z pfg $");
   33 
   34 #include <sys/param.h>
   35 #include <sys/pcpu.h>
   36 #include <sys/smp.h>
   37 #include <sys/systm.h>
   38 
   39 #include <net/vnet.h>
   40 
   41 #include <ddb/ddb.h>
   42 #include <ddb/db_sym.h>
   43 #include <ddb/db_variables.h>
   44 
   45 #include <opt_ddb.h>
   46 
   47 /*
   48  * Multiple symbol tables
   49  */
   50 #ifndef MAXNOSYMTABS
   51 #define MAXNOSYMTABS    3       /* mach, ux, emulator */
   52 #endif
   53 
   54 static db_symtab_t      db_symtabs[MAXNOSYMTABS] = {{0,},};
   55 static int db_nsymtab = 0;
   56 
   57 static db_symtab_t      *db_last_symtab; /* where last symbol was found */
   58 
   59 static c_db_sym_t       db_lookup( const char *symstr);
   60 static char             *db_qualify(c_db_sym_t sym, char *symtabname);
   61 static boolean_t        db_symbol_is_ambiguous(c_db_sym_t sym);
   62 static boolean_t        db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
   63 
   64 static int db_cpu = -1;
   65 
   66 #ifdef VIMAGE
   67 static void *db_vnet = NULL;
   68 #endif
   69 
   70 /*
   71  * Validate the CPU number used to interpret per-CPU variables so we can
   72  * avoid later confusion if an invalid CPU is requested.
   73  */
   74 int
   75 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
   76 {
   77 
   78         switch (op) {
   79         case DB_VAR_GET:
   80                 *valuep = db_cpu;
   81                 return (1);
   82 
   83         case DB_VAR_SET:
   84                 if (*(int *)valuep < -1 && *(int *)valuep > mp_maxid) {
   85                         db_printf("Invalid value: %d", *(int*)valuep);
   86                         return (0);
   87                 }
   88                 db_cpu = *(int *)valuep;
   89                 return (1);
   90 
   91         default:
   92                 db_printf("db_var_db_cpu: unknown operation\n");
   93                 return (0);
   94         }
   95 }
   96 
   97 /*
   98  * Read-only variable reporting the current CPU, which is what we use when
   99  * db_cpu is set to -1.
  100  */
  101 int
  102 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
  103 {
  104 
  105         switch (op) {
  106         case DB_VAR_GET:
  107                 *valuep = curcpu;
  108                 return (1);
  109 
  110         case DB_VAR_SET:
  111                 db_printf("Read-only variable.\n");
  112                 return (0);
  113 
  114         default:
  115                 db_printf("db_var_curcpu: unknown operation\n");
  116                 return (0);
  117         }
  118 }
  119 
  120 #ifdef VIMAGE
  121 /*
  122  * Validate the virtual network pointer used to interpret per-vnet global
  123  * variable expansion.  Right now we don't do much here, really we should
  124  * walk the global vnet list to check it's an OK pointer.
  125  */
  126 int
  127 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
  128 {
  129 
  130         switch (op) {
  131         case DB_VAR_GET:
  132                 *valuep = (db_expr_t)db_vnet;
  133                 return (1);
  134 
  135         case DB_VAR_SET:
  136                 db_vnet = *(void **)valuep;
  137                 return (1);
  138 
  139         default:
  140                 db_printf("db_var_db_vnet: unknown operation\n");
  141                 return (0);
  142         }
  143 }
  144 
  145 /*
  146  * Read-only variable reporting the current vnet, which is what we use when
  147  * db_vnet is set to NULL.
  148  */
  149 int
  150 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
  151 {
  152 
  153         switch (op) {
  154         case DB_VAR_GET:
  155                 *valuep = (db_expr_t)curvnet;
  156                 return (1);
  157 
  158         case DB_VAR_SET:
  159                 db_printf("Read-only variable.\n");
  160                 return (0);
  161 
  162         default:
  163                 db_printf("db_var_curcpu: unknown operation\n");
  164                 return (0);
  165         }
  166 }
  167 #endif
  168 
  169 /*
  170  * Add symbol table, with given name, to list of symbol tables.
  171  */
  172 void
  173 db_add_symbol_table(char *start, char *end, char *name, char *ref)
  174 {
  175         if (db_nsymtab >= MAXNOSYMTABS) {
  176                 printf ("No slots left for %s symbol table", name);
  177                 panic ("db_sym.c: db_add_symbol_table");
  178         }
  179 
  180         db_symtabs[db_nsymtab].start = start;
  181         db_symtabs[db_nsymtab].end = end;
  182         db_symtabs[db_nsymtab].name = name;
  183         db_symtabs[db_nsymtab].private = ref;
  184         db_nsymtab++;
  185 }
  186 
  187 /*
  188  *  db_qualify("vm_map", "ux") returns "unix:vm_map".
  189  *
  190  *  Note: return value points to static data whose content is
  191  *  overwritten by each call... but in practice this seems okay.
  192  */
  193 static char *
  194 db_qualify(c_db_sym_t sym, char *symtabname)
  195 {
  196         const char      *symname;
  197         static char     tmp[256];
  198 
  199         db_symbol_values(sym, &symname, 0);
  200         snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
  201         return tmp;
  202 }
  203 
  204 
  205 boolean_t
  206 db_eqname(const char *src, const char *dst, int c)
  207 {
  208         if (!strcmp(src, dst))
  209             return (TRUE);
  210         if (src[0] == c)
  211             return (!strcmp(src+1,dst));
  212         return (FALSE);
  213 }
  214 
  215 boolean_t
  216 db_value_of_name(const char *name, db_expr_t *valuep)
  217 {
  218         c_db_sym_t      sym;
  219 
  220         sym = db_lookup(name);
  221         if (sym == C_DB_SYM_NULL)
  222             return (FALSE);
  223         db_symbol_values(sym, &name, valuep);
  224         return (TRUE);
  225 }
  226 
  227 boolean_t
  228 db_value_of_name_pcpu(const char *name, db_expr_t *valuep)
  229 {
  230         static char     tmp[256];
  231         db_expr_t       value;
  232         c_db_sym_t      sym;
  233         int             cpu;
  234 
  235         if (db_cpu != -1)
  236                 cpu = db_cpu;
  237         else
  238                 cpu = curcpu;
  239         snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
  240         sym = db_lookup(tmp);
  241         if (sym == C_DB_SYM_NULL)
  242                 return (FALSE);
  243         db_symbol_values(sym, &name, &value);
  244         if (value < DPCPU_START || value >= DPCPU_STOP)
  245                 return (FALSE);
  246         *valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
  247         return (TRUE);
  248 }
  249 
  250 boolean_t
  251 db_value_of_name_vnet(const char *name, db_expr_t *valuep)
  252 {
  253 #ifdef VIMAGE
  254         static char     tmp[256];
  255         db_expr_t       value;
  256         c_db_sym_t      sym;
  257         struct vnet     *vnet;
  258 
  259         if (db_vnet != NULL)
  260                 vnet = db_vnet;
  261         else
  262                 vnet = curvnet;
  263         snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
  264         sym = db_lookup(tmp);
  265         if (sym == C_DB_SYM_NULL)
  266                 return (FALSE);
  267         db_symbol_values(sym, &name, &value);
  268         if (value < VNET_START || value >= VNET_STOP)
  269                 return (FALSE);
  270         *valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
  271         return (TRUE);
  272 #else
  273         return (FALSE);
  274 #endif
  275 }
  276 
  277 /*
  278  * Lookup a symbol.
  279  * If the symbol has a qualifier (e.g., ux:vm_map),
  280  * then only the specified symbol table will be searched;
  281  * otherwise, all symbol tables will be searched.
  282  */
  283 static c_db_sym_t
  284 db_lookup(const char *symstr)
  285 {
  286         c_db_sym_t sp;
  287         register int i;
  288         int symtab_start = 0;
  289         int symtab_end = db_nsymtab;
  290         register const char *cp;
  291 
  292         /*
  293          * Look for, remove, and remember any symbol table specifier.
  294          */
  295         for (cp = symstr; *cp; cp++) {
  296                 if (*cp == ':') {
  297                         for (i = 0; i < db_nsymtab; i++) {
  298                                 int n = strlen(db_symtabs[i].name);
  299 
  300                                 if (
  301                                     n == (cp - symstr) &&
  302                                     strncmp(symstr, db_symtabs[i].name, n) == 0
  303                                 ) {
  304                                         symtab_start = i;
  305                                         symtab_end = i + 1;
  306                                         break;
  307                                 }
  308                         }
  309                         if (i == db_nsymtab) {
  310                                 db_error("invalid symbol table name");
  311                         }
  312                         symstr = cp+1;
  313                 }
  314         }
  315 
  316         /*
  317          * Look in the specified set of symbol tables.
  318          * Return on first match.
  319          */
  320         for (i = symtab_start; i < symtab_end; i++) {
  321                 sp = X_db_lookup(&db_symtabs[i], symstr);
  322                 if (sp) {
  323                         db_last_symtab = &db_symtabs[i];
  324                         return sp;
  325                 }
  326         }
  327         return 0;
  328 }
  329 
  330 /*
  331  * If TRUE, check across symbol tables for multiple occurrences
  332  * of a name.  Might slow things down quite a bit.
  333  */
  334 static volatile boolean_t db_qualify_ambiguous_names = FALSE;
  335 
  336 /*
  337  * Does this symbol name appear in more than one symbol table?
  338  * Used by db_symbol_values to decide whether to qualify a symbol.
  339  */
  340 static boolean_t
  341 db_symbol_is_ambiguous(c_db_sym_t sym)
  342 {
  343         const char      *sym_name;
  344         register int    i;
  345         register
  346         boolean_t       found_once = FALSE;
  347 
  348         if (!db_qualify_ambiguous_names)
  349                 return FALSE;
  350 
  351         db_symbol_values(sym, &sym_name, 0);
  352         for (i = 0; i < db_nsymtab; i++) {
  353                 if (X_db_lookup(&db_symtabs[i], sym_name)) {
  354                         if (found_once)
  355                                 return TRUE;
  356                         found_once = TRUE;
  357                 }
  358         }
  359         return FALSE;
  360 }
  361 
  362 /*
  363  * Find the closest symbol to val, and return its name
  364  * and the difference between val and the symbol found.
  365  */
  366 c_db_sym_t
  367 db_search_symbol(db_addr_t val, db_strategy_t strategy, db_expr_t *offp)
  368 {
  369         register
  370         unsigned int    diff;
  371         size_t          newdiff;
  372         register 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 = 0;
  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 == 0)
  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 == 0 || 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 boolean_t
  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 int
  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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