usr/src/cmd/sgs/rtld/i386/_setup.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 2009 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*
  28  *      Copyright (c) 1988 AT&T
  29  *        All Rights Reserved
  30  */
  31 /*
  32  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
  33  */
  34
  35 /*
  36  * i386 specific setup routine  -  relocate ld.so's symbols, setup its
  37  * environment, map in loadable sections of the executable.
  38  *
  39  * Takes base address ld.so was loaded at, address of ld.so's dynamic
  40  * structure, address of process environment pointers, address of auxiliary
  41  * vector and * argv[0] (process name).
  42  * If errors occur, send process signal - otherwise
  43  * return executable's entry point to the bootstrap routine.
  44  */
  45
  46 #include        <signal.h>
  47 #include        <stdlib.h>
  48 #include        <sys/auxv.h>
  49 #include        <sys/types.h>
  50 #include        <sys/stat.h>
  51 #include        <link.h>
  52 #include        <dlfcn.h>
  53 #include        "_rtld.h"
  54 #include        "_audit.h"
  55 #include        "msg.h"
  56
  57 /* VARARGS */
  58 unsigned long
  59 _setup(Boot *ebp, Dyn *ld_dyn)
  60 {
  61         ulong_t         reladdr, relcount, ld_base = 0;
  62         ulong_t         relent = 0;
  63         ulong_t         strtab, soname, interp_base = 0;
  64         char            *_rt_name, **_envp, **_argv;
  65         int             _syspagsz = 0, fd = -1;
  66         uint_t          _flags = 0;
  67         uint_t          hwcap[2] = { 0, 0 };
  68         Dyn             *dyn_ptr;
  69         Phdr            *phdr = NULL;
  70         Rt_map          *lmp;
  71         auxv_t          *auxv, *_auxv;
  72         uid_t           uid = (uid_t)-1, euid = (uid_t)-1;
  73         gid_t           gid = (gid_t)-1, egid = (gid_t)-1;
  74         char            *_platform = NULL, *_execname = NULL, *_emulator = NULL;
  75         int             auxflags = -1;
  76
  77         /*
  78          * Scan the bootstrap structure to pick up the basics.
  79          */
  80         for (; ebp->eb_tag != EB_NULL; ebp++)
  81                 switch (ebp->eb_tag) {
  82                 case EB_LDSO_BASE:
  83                         ld_base = (unsigned long)ebp->eb_un.eb_val;
  84                         break;
  85                 case EB_ARGV:
  86                         _argv = (char **)ebp->eb_un.eb_ptr;
  87                         break;
  88                 case EB_ENVP:
  89                         _envp = (char **)ebp->eb_un.eb_ptr;
  90                         break;
  91                 case EB_AUXV:
  92                         _auxv = (auxv_t *)ebp->eb_un.eb_ptr;
  93                         break;
  94                 case EB_PAGESIZE:
  95                         _syspagsz = (int)ebp->eb_un.eb_val;
  96                         break;
  97                 }
  98
  99         /*
 100          * Search the aux. vector for the information passed by exec.
 101          */
 102         for (auxv = _auxv; auxv->a_type != AT_NULL; auxv++) {
 103                 switch (auxv->a_type) {
 104                 case AT_EXECFD:
 105                         /* this is the old exec that passes a file descriptor */
 106                         fd = (int)auxv->a_un.a_val;
 107                         break;
 108                 case AT_FLAGS:
 109                         /* processor flags (MAU available, etc) */
 110                         _flags = auxv->a_un.a_val;
 111                         break;
 112                 case AT_PAGESZ:
 113                         /* system page size */
 114                         _syspagsz = (int)auxv->a_un.a_val;
 115                         break;
 116                 case AT_PHDR:
 117                         /* address of the segment table */
 118                         phdr = (Phdr *)auxv->a_un.a_ptr;
 119                         break;
 120                 case AT_BASE:
 121                         /* interpreter base address */
 122                         if (ld_base == 0)
 123                                 ld_base = auxv->a_un.a_val;
 124                         interp_base = auxv->a_un.a_val;
 125                         break;
 126                 case AT_SUN_UID:
 127                         /* effective user id for the executable */
 128                         euid = (uid_t)auxv->a_un.a_val;
 129                         break;
 130                 case AT_SUN_RUID:
 131                         /* real user id for the executable */
 132                         uid = (uid_t)auxv->a_un.a_val;
 133                         break;
 134                 case AT_SUN_GID:
 135                         /* effective group id for the executable */
 136                         egid = (gid_t)auxv->a_un.a_val;
 137                         break;
 138                 case AT_SUN_RGID:
 139                         /* real group id for the executable */
 140                         gid = (gid_t)auxv->a_un.a_val;
 141                         break;
 142                 case AT_SUN_PLATFORM:
 143                         /* platform name */
 144                         _platform = auxv->a_un.a_ptr;
 145                         break;
 146                 case AT_SUN_EXECNAME:
 147                         /* full pathname of execed object */
 148                         _execname = auxv->a_un.a_ptr;
 149                         break;
 150                 case AT_SUN_AUXFLAGS:
 151                         /* auxiliary flags */
 152                         auxflags = (int)auxv->a_un.a_val;
 153                         break;
 154                 case AT_SUN_HWCAP:
 155                         /* hardware capabilities */
 156                         hwcap[0] = (uint_t)auxv->a_un.a_val;
 157                         break;
 158                 case AT_SUN_HWCAP2:
 159                         /* hardware capabilities */
 160                         hwcap[1] = (uint_t)auxv->a_un.a_val;
 161                         break;
 162                 case AT_SUN_EMULATOR:
 163                         /* name of emulation library, if any */
 164                         _emulator = auxv->a_un.a_ptr;
 165                         break;
 166                 }
 167         }
 168
 169         /*
 170          * Get needed info from ld.so's dynamic structure.
 171          */
 172         /* LINTED */
 173         dyn_ptr = (Dyn *)((char *)ld_dyn + ld_base);
 174         for (ld_dyn = dyn_ptr; ld_dyn->d_tag != DT_NULL; ld_dyn++) {
 175                 switch (ld_dyn->d_tag) {
 176                 case DT_REL:
 177                         reladdr = ld_dyn->d_un.d_ptr + ld_base;
 178                         break;
 179                 case DT_RELCOUNT:
 180                         relcount = ld_dyn->d_un.d_val;
 181                         break;
 182                 case DT_RELENT:
 183                         relent = ld_dyn->d_un.d_val;
 184                         break;
 185                 case DT_STRTAB:
 186                         strtab = ld_dyn->d_un.d_ptr + ld_base;
 187                         break;
 188                 case DT_SONAME:
 189                         soname = ld_dyn->d_un.d_val;
 190                         break;
 191                 }
 192         }
 193         _rt_name = (char *)strtab + soname;
 194
 195         /*
 196          * If we don't have a RELENT, just assume the size.
 197          */
 198         if (relent == 0)
 199                 relent = sizeof (Rel);
 200
 201         /*
 202          * As all global symbol references within ld.so.1 are protected
 203          * (symbolic), only RELATIVE and JMPSLOT relocations should be left
 204          * to process at runtime.  Process all relative relocations now.
 205          */
 206         for (; relcount; relcount--) {
 207                 ulong_t roffset;
 208
 209                 roffset = ((Rel *)reladdr)->r_offset + ld_base;
 210                 *((ulong_t *)roffset) += ld_base;
 211                 reladdr += relent;
 212         }
 213
 214         /*
 215          * If an emulation library is being used, use that as the linker's
 216          * effective executable name. The real executable is not linked by this
 217          * linker.
 218          */
 219         if (_emulator != NULL) {
 220                 _execname = _emulator;
 221                 rtld_flags2 |= RT_FL2_BRANDED;
 222         }
 223
 224         /*
 225          * Initialize the dyn_plt_ent_size field.  It currently contains the
 226          * size of the dyn_plt_template.  It still needs to be aligned and have
 227          * space for the 'dyn_data' area added.
 228          */
 229         dyn_plt_ent_size = ROUND(dyn_plt_ent_size, M_WORD_ALIGN) +
 230             sizeof (uintptr_t) + sizeof (uintptr_t) + sizeof (ulong_t) +
 231             sizeof (ulong_t) + sizeof (Sym);
 232
 233         /*
 234          * Continue with generic startup processing.
 235          */
 236         if ((lmp = setup((char **)_envp, (auxv_t *)_auxv, _flags, _platform,
 237             _syspagsz, _rt_name, ld_base, interp_base, fd, phdr,
 238             _execname, _argv, uid, euid, gid, egid, NULL, auxflags,
 239             hwcap)) == NULL) {
 240                 rtldexit(&lml_main, 1);
 241         }
 242
 243         return (LM_ENTRY_PT(lmp)());
 244 }