usr/src/cmd/sgs/rtld/amd64/_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  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
  28  */
  29
  30 /*
  31  * amd64 specific setup routine  -  relocate ld.so's symbols, setup its
  32  * environment, map in loadable sections of the executable.
  33  *
  34  * Takes base address ld.so was loaded at, address of ld.so's dynamic
  35  * structure, address of process environment pointers, address of auxiliary
  36  * vector and * argv[0] (process name).
  37  * If errors occur, send process signal - otherwise
  38  * return executable's entry point to the bootstrap routine.
  39  */
  40
  41 #include        <signal.h>
  42 #include        <stdlib.h>
  43 #include        <sys/auxv.h>
  44 #include        <sys/types.h>
  45 #include        <sys/stat.h>
  46 #include        <link.h>
  47 #include        <dlfcn.h>
  48 #include        "_rtld.h"
  49 #include        "_audit.h"
  50 #include        "msg.h"
  51
  52 /* VARARGS */
  53 unsigned long
  54 _setup(Boot *ebp, Dyn *ld_dyn)
  55 {
  56         ulong_t         reladdr, relacount, ld_base = 0;
  57         ulong_t         relaent = 0, pltrelsz = 0;
  58         ulong_t         strtab, soname, interp_base = 0;
  59         char            *_rt_name, **_envp, **_argv;
  60         int             _syspagsz = 0, fd = -1;
  61         uint_t          _flags = 0;
  62         uint_t          hwcap[2] = { 0, 0 };
  63         Dyn             *dyn_ptr;
  64         Phdr            *phdr = NULL;
  65         Rt_map          *lmp;
  66         auxv_t          *auxv, *_auxv;
  67         uid_t           uid = (uid_t)-1, euid = (uid_t)-1;
  68         gid_t           gid = (gid_t)-1, egid = (gid_t)-1;
  69         char            *_platform = NULL, *_execname = NULL, *_emulator = NULL;
  70         int             auxflags = -1;
  71
  72         /*
  73          * Scan the bootstrap structure to pick up the basics.
  74          */
  75         for (; ebp->eb_tag != EB_NULL; ebp++)
  76                 switch (ebp->eb_tag) {
  77                 case EB_LDSO_BASE:
  78                         ld_base = (unsigned long)ebp->eb_un.eb_val;
  79                         break;
  80                 case EB_ARGV:
  81                         _argv = (char **)ebp->eb_un.eb_ptr;
  82                         break;
  83                 case EB_ENVP:
  84                         _envp = (char **)ebp->eb_un.eb_ptr;
  85                         break;
  86                 case EB_AUXV:
  87                         _auxv = (auxv_t *)ebp->eb_un.eb_ptr;
  88                         break;
  89                 case EB_PAGESIZE:
  90                         _syspagsz = (int)ebp->eb_un.eb_val;
  91                         break;
  92                 }
  93
  94         /*
  95          * Search the aux. vector for the information passed by exec.
  96          */
  97         for (auxv = _auxv; auxv->a_type != AT_NULL; auxv++) {
  98                 switch (auxv->a_type) {
  99                 case AT_EXECFD:
 100                         /* this is the old exec that passes a file descriptor */
 101                         fd = (int)auxv->a_un.a_val;
 102                         break;
 103                 case AT_FLAGS:
 104                         /* processor flags (MAU available, etc) */
 105                         _flags = auxv->a_un.a_val;
 106                         break;
 107                 case AT_PAGESZ:
 108                         /* system page size */
 109                         _syspagsz = (int)auxv->a_un.a_val;
 110                         break;
 111                 case AT_PHDR:
 112                         /* address of the segment table */
 113                         phdr = (Phdr *)auxv->a_un.a_ptr;
 114                         break;
 115                 case AT_BASE:
 116                         /* interpreter base address */
 117                         if (ld_base == 0)
 118                                 ld_base = auxv->a_un.a_val;
 119                         interp_base = auxv->a_un.a_val;
 120                         break;
 121                 case AT_SUN_UID:
 122                         /* effective user id for the executable */
 123                         euid = (uid_t)auxv->a_un.a_val;
 124                         break;
 125                 case AT_SUN_RUID:
 126                         /* real user id for the executable */
 127                         uid = (uid_t)auxv->a_un.a_val;
 128                         break;
 129                 case AT_SUN_GID:
 130                         /* effective group id for the executable */
 131                         egid = (gid_t)auxv->a_un.a_val;
 132                         break;
 133                 case AT_SUN_RGID:
 134                         /* real group id for the executable */
 135                         gid = (gid_t)auxv->a_un.a_val;
 136                         break;
 137                 case AT_SUN_PLATFORM:
 138                         /* platform name */
 139                         _platform = auxv->a_un.a_ptr;
 140                         break;
 141                 case AT_SUN_EXECNAME:
 142                         /* full pathname of execed object */
 143                         _execname = auxv->a_un.a_ptr;
 144                         break;
 145                 case AT_SUN_AUXFLAGS:
 146                         /* auxiliary flags */
 147                         auxflags = (int)auxv->a_un.a_val;
 148                         break;
 149                 case AT_SUN_HWCAP:
 150                         /* hardware capabilities */
 151                         hwcap[0] = (uint_t)auxv->a_un.a_val;
 152                         break;
 153                 case AT_SUN_HWCAP2:
 154                         /* hardware capabilities */
 155                         hwcap[1] = (uint_t)auxv->a_un.a_val;
 156                         break;
 157                 case AT_SUN_EMULATOR:
 158                         /* name of emulation library, if any */
 159                         _emulator = auxv->a_un.a_ptr;
 160                         break;
 161                 }
 162         }
 163
 164         /*
 165          * Get needed info from ld.so's dynamic structure.
 166          */
 167         /* LINTED */
 168         dyn_ptr = (Dyn *)((char *)ld_dyn + ld_base);
 169         for (ld_dyn = dyn_ptr; ld_dyn->d_tag != DT_NULL; ld_dyn++) {
 170                 switch (ld_dyn->d_tag) {
 171                 case DT_RELA:
 172                         reladdr = ld_dyn->d_un.d_ptr + ld_base;
 173                         break;
 174                 case DT_RELACOUNT:
 175                         relacount = ld_dyn->d_un.d_val;
 176                         break;
 177                 case DT_RELAENT:
 178                         relaent = ld_dyn->d_un.d_val;
 179                         break;
 180                 case DT_PLTRELSZ:
 181                         pltrelsz = ld_dyn->d_un.d_val;
 182                         break;
 183                 case DT_STRTAB:
 184                         strtab = ld_dyn->d_un.d_ptr + ld_base;
 185                         break;
 186                 case DT_SONAME:
 187                         soname = ld_dyn->d_un.d_val;
 188                         break;
 189                 }
 190         }
 191         _rt_name = (char *)strtab + soname;
 192
 193         /*
 194          * If we don't have a RELAENT, just assume the size.
 195          */
 196         if (relaent == 0)
 197                 relaent = sizeof (Rela);
 198
 199         /*
 200          * As all global symbol references within ld.so.1 are protected
 201          * (symbolic), only RELATIVE and JMPSLOT relocations should be left
 202          * to process at runtime.  Process all relocations now.
 203          */
 204         relacount += (pltrelsz / relaent);
 205         for (; relacount; relacount--) {
 206                 ulong_t roffset;
 207
 208                 roffset = ((Rela *)reladdr)->r_offset + ld_base;
 209                 *((ulong_t *)roffset) += ld_base +
 210                     ((Rela *)reladdr)->r_addend;
 211                 reladdr += relaent;
 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 }