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/8.0/sys/ddb/db_sym.c 196019 2009-08-01 19:26:27Z rwatson $");
   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 extern uintptr_t        *__start_set_vnet;
   68 extern uintptr_t        *__stop_set_vnet;
   69 
   70 #define VNET_START      (uintptr_t)&__start_set_vnet
   71 #define VNET_STOP       (uintptr_t)&__stop_set_vnet
   72 
   73 static void *db_vnet = NULL;
   74 #endif
   75 
   76 /*
   77  * Validate the CPU number used to interpret per-CPU variables so we can
   78  * avoid later confusion if an invalid CPU is requested.
   79  */
   80 int
   81 db_var_db_cpu(struct db_variable *vp, db_expr_t *valuep, int op)
   82 {
   83 
   84         switch (op) {
   85         case DB_VAR_GET:
   86                 *valuep = db_cpu;
   87                 return (1);
   88 
   89         case DB_VAR_SET:
   90                 if (*(int *)valuep < -1 && *(int *)valuep > mp_maxid) {
   91                         db_printf("Invalid value: %d", *(int*)valuep);
   92                         return (0);
   93                 }
   94                 db_cpu = *(int *)valuep;
   95                 return (1);
   96 
   97         default:
   98                 db_printf("db_var_db_cpu: unknown operation\n");
   99                 return (0);
  100         }
  101 }
  102 
  103 /*
  104  * Read-only variable reporting the current CPU, which is what we use when
  105  * db_cpu is set to -1.
  106  */
  107 int
  108 db_var_curcpu(struct db_variable *vp, db_expr_t *valuep, int op)
  109 {
  110 
  111         switch (op) {
  112         case DB_VAR_GET:
  113                 *valuep = curcpu;
  114                 return (1);
  115 
  116         case DB_VAR_SET:
  117                 db_printf("Read-only variable.\n");
  118                 return (0);
  119 
  120         default:
  121                 db_printf("db_var_curcpu: unknown operation\n");
  122                 return (0);
  123         }
  124 }
  125 
  126 #ifdef VIMAGE
  127 /*
  128  * Validate the virtual network pointer used to interpret per-vnet global
  129  * variable expansion.  Right now we don't do much here, really we should
  130  * walk the global vnet list to check it's an OK pointer.
  131  */
  132 int
  133 db_var_db_vnet(struct db_variable *vp, db_expr_t *valuep, int op)
  134 {
  135 
  136         switch (op) {
  137         case DB_VAR_GET:
  138                 *valuep = (db_expr_t)db_vnet;
  139                 return (1);
  140 
  141         case DB_VAR_SET:
  142                 db_vnet = *(void **)valuep;
  143                 return (1);
  144 
  145         default:
  146                 db_printf("db_var_db_vnet: unknown operation\n");
  147                 return (0);
  148         }
  149 }
  150 
  151 /*
  152  * Read-only variable reporting the current vnet, which is what we use when
  153  * db_vnet is set to NULL.
  154  */
  155 int
  156 db_var_curvnet(struct db_variable *vp, db_expr_t *valuep, int op)
  157 {
  158 
  159         switch (op) {
  160         case DB_VAR_GET:
  161                 *valuep = (db_expr_t)curvnet;
  162                 return (1);
  163 
  164         case DB_VAR_SET:
  165                 db_printf("Read-only variable.\n");
  166                 return (0);
  167 
  168         default:
  169                 db_printf("db_var_curcpu: unknown operation\n");
  170                 return (0);
  171         }
  172 }
  173 #endif
  174 
  175 /*
  176  * Add symbol table, with given name, to list of symbol tables.
  177  */
  178 void
  179 db_add_symbol_table(start, end, name, ref)
  180         char *start;
  181         char *end;
  182         char *name;
  183         char *ref;
  184 {
  185         if (db_nsymtab >= MAXNOSYMTABS) {
  186                 printf ("No slots left for %s symbol table", name);
  187                 panic ("db_sym.c: db_add_symbol_table");
  188         }
  189 
  190         db_symtabs[db_nsymtab].start = start;
  191         db_symtabs[db_nsymtab].end = end;
  192         db_symtabs[db_nsymtab].name = name;
  193         db_symtabs[db_nsymtab].private = ref;
  194         db_nsymtab++;
  195 }
  196 
  197 /*
  198  *  db_qualify("vm_map", "ux") returns "unix:vm_map".
  199  *
  200  *  Note: return value points to static data whose content is
  201  *  overwritten by each call... but in practice this seems okay.
  202  */
  203 static char *
  204 db_qualify(sym, symtabname)
  205         c_db_sym_t      sym;
  206         register char   *symtabname;
  207 {
  208         const char      *symname;
  209         static char     tmp[256];
  210 
  211         db_symbol_values(sym, &symname, 0);
  212         snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
  213         return tmp;
  214 }
  215 
  216 
  217 boolean_t
  218 db_eqname(src, dst, c)
  219         const char *src;
  220         const char *dst;
  221         int c;
  222 {
  223         if (!strcmp(src, dst))
  224             return (TRUE);
  225         if (src[0] == c)
  226             return (!strcmp(src+1,dst));
  227         return (FALSE);
  228 }
  229 
  230 boolean_t
  231 db_value_of_name(name, valuep)
  232         const char      *name;
  233         db_expr_t       *valuep;
  234 {
  235         c_db_sym_t      sym;
  236 
  237         sym = db_lookup(name);
  238         if (sym == C_DB_SYM_NULL)
  239             return (FALSE);
  240         db_symbol_values(sym, &name, valuep);
  241         return (TRUE);
  242 }
  243 
  244 boolean_t
  245 db_value_of_name_pcpu(name, valuep)
  246         const char      *name;
  247         db_expr_t       *valuep;
  248 {
  249         static char     tmp[256];
  250         db_expr_t       value;
  251         c_db_sym_t      sym;
  252         int             cpu;
  253 
  254         if (db_cpu != -1)
  255                 cpu = db_cpu;
  256         else
  257                 cpu = curcpu;
  258         snprintf(tmp, sizeof(tmp), "pcpu_entry_%s", name);
  259         sym = db_lookup(tmp);
  260         if (sym == C_DB_SYM_NULL)
  261                 return (FALSE);
  262         db_symbol_values(sym, &name, &value);
  263         if (value < DPCPU_START || value >= DPCPU_STOP)
  264                 return (FALSE);
  265         *valuep = (db_expr_t)((uintptr_t)value + dpcpu_off[cpu]);
  266         return (TRUE);
  267 }
  268 
  269 boolean_t
  270 db_value_of_name_vnet(name, valuep)
  271         const char      *name;
  272         db_expr_t       *valuep;
  273 {
  274 #ifdef VIMAGE
  275         static char     tmp[256];
  276         db_expr_t       value;
  277         c_db_sym_t      sym;
  278         struct vnet     *vnet;
  279 
  280         if (db_vnet != NULL)
  281                 vnet = db_vnet;
  282         else
  283                 vnet = curvnet;
  284         snprintf(tmp, sizeof(tmp), "vnet_entry_%s", name);
  285         sym = db_lookup(tmp);
  286         if (sym == C_DB_SYM_NULL)
  287                 return (FALSE);
  288         db_symbol_values(sym, &name, &value);
  289         if (value < VNET_START || value >= VNET_STOP)
  290                 return (FALSE);
  291         *valuep = (db_expr_t)((uintptr_t)value + vnet->vnet_data_base);
  292         return (TRUE);
  293 #else
  294         return (FALSE);
  295 #endif
  296 }
  297 
  298 /*
  299  * Lookup a symbol.
  300  * If the symbol has a qualifier (e.g., ux:vm_map),
  301  * then only the specified symbol table will be searched;
  302  * otherwise, all symbol tables will be searched.
  303  */
  304 static c_db_sym_t
  305 db_lookup(symstr)
  306         const char *symstr;
  307 {
  308         c_db_sym_t sp;
  309         register int i;
  310         int symtab_start = 0;
  311         int symtab_end = db_nsymtab;
  312         register const char *cp;
  313 
  314         /*
  315          * Look for, remove, and remember any symbol table specifier.
  316          */
  317         for (cp = symstr; *cp; cp++) {
  318                 if (*cp == ':') {
  319                         for (i = 0; i < db_nsymtab; i++) {
  320                                 int n = strlen(db_symtabs[i].name);
  321 
  322                                 if (
  323                                     n == (cp - symstr) &&
  324                                     strncmp(symstr, db_symtabs[i].name, n) == 0
  325                                 ) {
  326                                         symtab_start = i;
  327                                         symtab_end = i + 1;
  328                                         break;
  329                                 }
  330                         }
  331                         if (i == db_nsymtab) {
  332                                 db_error("invalid symbol table name");
  333                         }
  334                         symstr = cp+1;
  335                 }
  336         }
  337 
  338         /*
  339          * Look in the specified set of symbol tables.
  340          * Return on first match.
  341          */
  342         for (i = symtab_start; i < symtab_end; i++) {
  343                 sp = X_db_lookup(&db_symtabs[i], symstr);
  344                 if (sp) {
  345                         db_last_symtab = &db_symtabs[i];
  346                         return sp;
  347                 }
  348         }
  349         return 0;
  350 }
  351 
  352 /*
  353  * If TRUE, check across symbol tables for multiple occurrences
  354  * of a name.  Might slow things down quite a bit.
  355  */
  356 static volatile boolean_t db_qualify_ambiguous_names = FALSE;
  357 
  358 /*
  359  * Does this symbol name appear in more than one symbol table?
  360  * Used by db_symbol_values to decide whether to qualify a symbol.
  361  */
  362 static boolean_t
  363 db_symbol_is_ambiguous(sym)
  364         c_db_sym_t      sym;
  365 {
  366         const char      *sym_name;
  367         register int    i;
  368         register
  369         boolean_t       found_once = FALSE;
  370 
  371         if (!db_qualify_ambiguous_names)
  372                 return FALSE;
  373 
  374         db_symbol_values(sym, &sym_name, 0);
  375         for (i = 0; i < db_nsymtab; i++) {
  376                 if (X_db_lookup(&db_symtabs[i], sym_name)) {
  377                         if (found_once)
  378                                 return TRUE;
  379                         found_once = TRUE;
  380                 }
  381         }
  382         return FALSE;
  383 }
  384 
  385 /*
  386  * Find the closest symbol to val, and return its name
  387  * and the difference between val and the symbol found.
  388  */
  389 c_db_sym_t
  390 db_search_symbol( val, strategy, offp)
  391         register db_addr_t      val;
  392         db_strategy_t           strategy;
  393         db_expr_t               *offp;
  394 {
  395         register
  396         unsigned int    diff;
  397         size_t          newdiff;
  398         register int    i;
  399         c_db_sym_t      ret = C_DB_SYM_NULL, sym;
  400 
  401         newdiff = diff = ~0;
  402         for (i = 0; i < db_nsymtab; i++) {
  403             sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
  404             if (newdiff < diff) {
  405                 db_last_symtab = &db_symtabs[i];
  406                 diff = newdiff;
  407                 ret = sym;
  408             }
  409         }
  410         *offp = diff;
  411         return ret;
  412 }
  413 
  414 /*
  415  * Return name and value of a symbol
  416  */
  417 void
  418 db_symbol_values(sym, namep, valuep)
  419         c_db_sym_t      sym;
  420         const char      **namep;
  421         db_expr_t       *valuep;
  422 {
  423         db_expr_t       value;
  424 
  425         if (sym == DB_SYM_NULL) {
  426                 *namep = 0;
  427                 return;
  428         }
  429 
  430         X_db_symbol_values(db_last_symtab, sym, namep, &value);
  431 
  432         if (db_symbol_is_ambiguous(sym))
  433                 *namep = db_qualify(sym, db_last_symtab->name);
  434         if (valuep)
  435                 *valuep = value;
  436 }
  437 
  438 
  439 /*
  440  * Print a the closest symbol to value
  441  *
  442  * After matching the symbol according to the given strategy
  443  * we print it in the name+offset format, provided the symbol's
  444  * value is close enough (eg smaller than db_maxoff).
  445  * We also attempt to print [filename:linenum] when applicable
  446  * (eg for procedure names).
  447  *
  448  * If we could not find a reasonable name+offset representation,
  449  * then we just print the value in hex.  Small values might get
  450  * bogus symbol associations, e.g. 3 might get some absolute
  451  * value like _INCLUDE_VERSION or something, therefore we do
  452  * not accept symbols whose value is "small" (and use plain hex).
  453  */
  454 
  455 db_expr_t       db_maxoff = 0x10000;
  456 
  457 void
  458 db_printsym(off, strategy)
  459         db_expr_t       off;
  460         db_strategy_t   strategy;
  461 {
  462         db_expr_t       d;
  463         char            *filename;
  464         const char      *name;
  465         db_expr_t       value;
  466         int             linenum;
  467         c_db_sym_t      cursym;
  468 
  469         cursym = db_search_symbol(off, strategy, &d);
  470         db_symbol_values(cursym, &name, &value);
  471         if (name == 0)
  472                 value = off;
  473         if (value >= DB_SMALL_VALUE_MIN && value <= DB_SMALL_VALUE_MAX) {
  474                 db_printf("%+#lr", (long)off);
  475                 return;
  476         }
  477         if (name == 0 || d >= (unsigned long)db_maxoff) {
  478                 db_printf("%#lr", (unsigned long)off);
  479                 return;
  480         }
  481 #ifdef DDB_NUMSYM
  482         db_printf("%#lr = %s", (unsigned long)off, name);
  483 #else
  484         db_printf("%s", name);
  485 #endif
  486         if (d)
  487                 db_printf("+%+#lr", (long)d);
  488         if (strategy == DB_STGY_PROC) {
  489                 if (db_line_at_pc(cursym, &filename, &linenum, off))
  490                         db_printf(" [%s:%d]", filename, linenum);
  491         }
  492 }
  493 
  494 static boolean_t
  495 db_line_at_pc( sym, filename, linenum, pc)
  496         c_db_sym_t      sym;
  497         char            **filename;
  498         int             *linenum;
  499         db_expr_t       pc;
  500 {
  501         return X_db_line_at_pc( db_last_symtab, sym, filename, linenum, pc);
  502 }
  503 
  504 int
  505 db_sym_numargs(sym, nargp, argnames)
  506         c_db_sym_t      sym;
  507         int             *nargp;
  508         char            **argnames;
  509 {
  510         return X_db_sym_numargs(db_last_symtab, sym, nargp, argnames);
  511 }

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