usr/src/cmd/sgs/rtld/sparc/common_sparc.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 1998, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 #include        <stdio.h>
  27 #include        <strings.h>
  28 #include        <sys/elf.h>
  29 #include        <sys/elf_SPARC.h>
  30 #include        <alloca.h>
  31 #include        "_rtld.h"
  32 #include        "_elf.h"
  33 #include        "msg.h"
  34 #include        "conv.h"
  35
  36 /*
  37  *
  38  *  Matrix of legal combinations of usage of a given register:
  39  *
  40  *      Obj1\Obj2       Scratch Named
  41  *      Scratch          OK      NO
  42  *      Named            NO      *
  43  *
  44  *  * OK if the symbols are identical, NO if they are not.  Two symbols
  45  *  are identical if and only if one of the following is true:
  46  *        A. They are both global and have the same name.
  47  *        B. They are both local, have the same name, and are defined in
  48  *        the same object.  (Note that a local symbol in one object is
  49  *        never identical to a local symbol in another object, even if the
  50  *        name is the same.)
  51  *
  52  *  Matrix of legal combinations of st_shndx for the same register symbol:
  53  *
  54  *      Obj1\Obj2       UNDEF   ABS
  55  *      UNDEF            OK      OK
  56  *      ABS              OK      NO
  57  */
  58
  59 /*
  60  * Test the compatiblity of two register symbols, 0 pass, >0 fail
  61  */
  62 static uintptr_t
  63 check_regsyms(Sym *sym1, const char *name1, Sym *sym2, const char *name2)
  64 {
  65         if ((sym1->st_name == 0) && (sym2->st_name == 0))
  66                 return (0);     /* scratches are always compatible */
  67
  68         if ((ELF_ST_BIND(sym1->st_info) == STB_LOCAL) ||
  69             (ELF_ST_BIND(sym2->st_info) == STB_LOCAL)) {
  70                 if (sym1->st_value == sym2->st_value)
  71                         return (1);     /* local symbol incompat */
  72                 return (0);             /* no other prob from locals */
  73         }
  74
  75         if (sym1->st_value == sym2->st_value) {
  76                 /* NOTE this just avoids strcmp */
  77                 if ((sym1->st_name == 0) || (sym2->st_name == 0))
  78                         return (2);     /* can't match scratch to named */
  79
  80                 if (strcmp(name1, name2) != 0)
  81                         return (4);     /* diff name, same register value */
  82
  83                 if ((sym1->st_shndx == SHN_ABS) && (sym2->st_shndx == SHN_ABS))
  84                         return (3);     /* multiply defined */
  85         } else if (strcmp(name1, name2) == 0)
  86                 return (5);     /* same name, diff register value */
  87
  88         return (0);
  89 }
  90
  91 int
  92 elf_regsyms(Rt_map *lmp)
  93 {
  94         Dyn     *dyn;
  95         Dyninfo *dip;
  96         Sym     *symdef;
  97         ulong_t rsymndx;
  98
  99         /*
 100          * Scan through the .dynamic section of this object looking for all
 101          * DT_REGISTER entries.  For each DT_REGISTER entry found identify the
 102          * register symbol it identifies and confirm that it doesn't conflict
 103          * with any other register symbols.
 104          */
 105         for (dyn = DYN(lmp), dip = DYNINFO(lmp);
 106             !(dip->di_flags & FLG_DI_IGNORE); dyn++, dip++) {
 107                 Reglist *rp;
 108
 109                 if ((dip->di_flags & FLG_DI_REGISTER) == 0)
 110                         continue;
 111
 112                 /*
 113                  * Get the local symbol table entry.
 114                  */
 115                 rsymndx = dyn->d_un.d_val;
 116                 symdef = (Sym *)((unsigned long)SYMTAB(lmp) +
 117                     (rsymndx * SYMENT(lmp)));
 118
 119                 for (rp = reglist; rp; rp = rp->rl_next) {
 120                         Conv_inv_buf_t  inv_buf;
 121                         const char      *str, *sym1, *sym2;
 122
 123                         if (rp->rl_sym == symdef) {
 124                                 /*
 125                                  * Same symbol definition - everything is a-ok.
 126                                  */
 127                                 return (1);
 128                         }
 129
 130                         sym1 = (STRTAB(rp->rl_lmp) + rp->rl_sym->st_name);
 131                         sym2 = (STRTAB(lmp) + symdef->st_name);
 132
 133                         if (check_regsyms(rp->rl_sym, sym1, symdef, sym2) == 0)
 134                                 continue;
 135
 136                         if ((str = demangle(sym1)) != sym1) {
 137                                 char    *_str = alloca(strlen(str) + 1);
 138                                 (void) strcpy(_str, str);
 139                                 sym1 = (const char *)_str;
 140                         }
 141                         sym2 = demangle(sym2);
 142
 143                         if (LIST(lmp)->lm_flags & LML_FLG_TRC_WARN) {
 144                                 (void) printf(MSG_INTL(MSG_LDD_REG_SYMCONF),
 145                                     conv_sym_SPARC_value(symdef->st_value,
 146                                     0, &inv_buf), NAME(rp->rl_lmp),
 147                                     sym1, NAME(lmp), sym2);
 148                         } else {
 149                                 eprintf(LIST(lmp), ERR_FATAL,
 150                                     MSG_INTL(MSG_REG_SYMCONF),
 151                                     conv_sym_SPARC_value(symdef->st_value,
 152                                     0, &inv_buf), NAME(rp->rl_lmp),
 153                                     sym1, NAME(lmp), sym2);
 154                                 return (0);
 155                         }
 156                 }
 157                 if ((rp = calloc(sizeof (Reglist), 1)) == NULL)
 158                         return (0);
 159                 rp->rl_lmp = lmp;
 160                 rp->rl_sym = symdef;
 161                 rp->rl_next = reglist;
 162                 reglist = rp;
 163         }
 164         return (1);
 165 }