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

     /*
      * 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
     * 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.
     *
     * $FreeBSD: releng/5.0/sys/ddb/db_sym.c 92756 2002-03-20 05:14:42Z alfred $
     */
    
    /*
     *      Author: David B. Golub, Carnegie Mellon University
     *      Date:   7/90
     */
    #include <sys/param.h>
    #include <sys/systm.h>
    
    #include <ddb/ddb.h>
    #include <ddb/db_sym.h>
    
    /*
     * Multiple symbol tables
     */
    #ifndef MAXNOSYMTABS
    #define MAXNOSYMTABS    3       /* mach, ux, emulator */
    #endif
    
    static db_symtab_t      db_symtabs[MAXNOSYMTABS] = {{0,},};
    static int db_nsymtab = 0;
    
    static db_symtab_t      *db_last_symtab; /* where last symbol was found */
    
    static c_db_sym_t       db_lookup( const char *symstr);
    static char             *db_qualify(c_db_sym_t sym, char *symtabname);
    static boolean_t        db_symbol_is_ambiguous(c_db_sym_t sym);
    static boolean_t        db_line_at_pc(c_db_sym_t, char **, int *, db_expr_t);
    
    /*
     * Add symbol table, with given name, to list of symbol tables.
     */
    void
    db_add_symbol_table(start, end, name, ref)
            char *start;
            char *end;
            char *name;
            char *ref;
    {
            if (db_nsymtab >= MAXNOSYMTABS) {
                    printf ("No slots left for %s symbol table", name);
                    panic ("db_sym.c: db_add_symbol_table");
            }
    
            db_symtabs[db_nsymtab].start = start;
            db_symtabs[db_nsymtab].end = end;
            db_symtabs[db_nsymtab].name = name;
            db_symtabs[db_nsymtab].private = ref;
            db_nsymtab++;
    }
    
    /*
     *  db_qualify("vm_map", "ux") returns "unix:vm_map".
     *
     *  Note: return value points to static data whose content is
     *  overwritten by each call... but in practice this seems okay.
     */
    static char *
    db_qualify(sym, symtabname)
            c_db_sym_t      sym;
            register char   *symtabname;
    {
            const char      *symname;
            static char     tmp[256];
    
            db_symbol_values(sym, &symname, 0);
            snprintf(tmp, sizeof(tmp), "%s:%s", symtabname, symname);
            return tmp;
    }
    
    
    boolean_t
    db_eqname(src, dst, c)
           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);
   }
   
   boolean_t
   db_value_of_name(name, valuep)
           const char      *name;
           db_expr_t       *valuep;
   {
           c_db_sym_t      sym;
   
           sym = db_lookup(name);
           if (sym == C_DB_SYM_NULL)
               return (FALSE);
           db_symbol_values(sym, &name, valuep);
           return (TRUE);
   }
   
   
   /*
    * Lookup a symbol.
    * 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.
    */
   static c_db_sym_t
   db_lookup(symstr)
           const char *symstr;
   {
           c_db_sym_t sp;
           register int i;
           int symtab_start = 0;
           int symtab_end = db_nsymtab;
           register const char *cp;
   
           /*
            * Look for, remove, and remember any symbol table specifier.
            */
           for (cp = symstr; *cp; cp++) {
                   if (*cp == ':') {
                           for (i = 0; i < db_nsymtab; i++) {
                                   int n = strlen(db_symtabs[i].name);
   
                                   if (
                                       n == (cp - symstr) &&
                                       strncmp(symstr, db_symtabs[i].name, n) == 0
                                   ) {
                                           symtab_start = i;
                                           symtab_end = i + 1;
                                           break;
                                   }
                           }
                           if (i == db_nsymtab) {
                                   db_error("invalid symbol table name");
                           }
                           symstr = cp+1;
                   }
           }
   
           /*
            * Look in the specified set of symbol tables.
            * Return on first match.
            */
           for (i = symtab_start; i < symtab_end; i++) {
                   sp = X_db_lookup(&db_symtabs[i], symstr);
                   if (sp) {
                           db_last_symtab = &db_symtabs[i];
                           return sp;
                   }
           }
           return 0;
   }
   
   /*
    * If TRUE, check across symbol tables for multiple occurrences
    * of a name.  Might slow things down quite a bit.
    */
   static volatile boolean_t db_qualify_ambiguous_names = FALSE;
   
   /*
    * Does this symbol name appear in more than one symbol table?
    * Used by db_symbol_values to decide whether to qualify a symbol.
    */
   static boolean_t
   db_symbol_is_ambiguous(sym)
           c_db_sym_t      sym;
   {
           const char      *sym_name;
           register int    i;
           register
           boolean_t       found_once = FALSE;
   
           if (!db_qualify_ambiguous_names)
                   return FALSE;
   
           db_symbol_values(sym, &sym_name, 0);
           for (i = 0; i < db_nsymtab; i++) {
                   if (X_db_lookup(&db_symtabs[i], sym_name)) {
                           if (found_once)
                                   return TRUE;
                           found_once = TRUE;
                   }
           }
           return FALSE;
   }
   
   /*
    * Find the closest symbol to val, and return its name
    * and the difference between val and the symbol found.
    */
   c_db_sym_t
   db_search_symbol( val, strategy, offp)
           register db_addr_t      val;
           db_strategy_t           strategy;
           db_expr_t               *offp;
   {
           register
           unsigned int    diff;
           size_t          newdiff;
           register int    i;
           c_db_sym_t      ret = C_DB_SYM_NULL, sym;
   
           newdiff = diff = ~0;
           db_last_symtab = 0;
           for (i = 0; i < db_nsymtab; i++) {
               sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);
               if (newdiff < diff) {
                   db_last_symtab = &db_symtabs[i];
                   diff = newdiff;
                   ret = sym;
               }
           }
           *offp = diff;
           return ret;
   }
   
   /*
    * Return name and value of a symbol
    */
   void
   db_symbol_values(sym, namep, valuep)
           c_db_sym_t      sym;
           const char      **namep;
           db_expr_t       *valuep;
   {
           db_expr_t       value;
   
           if (sym == DB_SYM_NULL) {
                   *namep = 0;
                   return;
           }
   
           X_db_symbol_values(db_last_symtab, sym, namep, &value);
   
           if (db_symbol_is_ambiguous(sym))
                   *namep = db_qualify(sym, db_last_symtab->name);
           if (valuep)
                   *valuep = value;
   }
   
   
   /*
    * 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 "small" (and use plain hex).
    */
   
   db_expr_t       db_maxoff = 0x10000;
   
   void
   db_printsym(off, strategy)
           db_expr_t       off;
           db_strategy_t   strategy;
   {
           db_expr_t       d;
           char            *filename;
           const char      *name;
           db_expr_t       value;
           int             linenum;
           c_db_sym_t      cursym;
   
           cursym = db_search_symbol(off, strategy, &d);
           db_symbol_values(cursym, &name, &value);
           if (name == 0)
                   value = off;
           if (value >= DB_SMALL_VALUE_MIN && value <= DB_SMALL_VALUE_MAX) {
                   db_printf("%+#lr", (long)off);
                   return;
           }
           if (name == 0 || d >= (unsigned long)db_maxoff) {
                   db_printf("%#lr", (unsigned long)off);
                   return;
           }
           db_printf("%s", name);
           if (d)
                   db_printf("+%+#lr", (long)d);
           if (strategy == DB_STGY_PROC) {
                   if (db_line_at_pc(cursym, &filename, &linenum, off))
                           db_printf(" [%s:%d]", filename, linenum);
           }
   }
   
   static boolean_t
   db_line_at_pc( sym, filename, linenum, pc)
           c_db_sym_t      sym;
           char            **filename;
           int             *linenum;
           db_expr_t       pc;
   {
           return X_db_line_at_pc( db_last_symtab, sym, filename, linenum, pc);
   }
   
   int
   db_sym_numargs(sym, nargp, argnames)
           c_db_sym_t      sym;
           int             *nargp;
           char            **argnames;
   {
           return X_db_sym_numargs(db_last_symtab, sym, nargp, argnames);
   }

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