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) 2018, Joyent, Inc. 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 /* 53 * Number of bytes to save for register usage. 54 */ 55 uint_t _plt_save_size; 56 void (*_plt_fp_save)(void *); 57 void (*_plt_fp_restore)(void *); 58 59 extern void _elf_rtbndr_fp_save_orig(void *); 60 extern void _elf_rtbndr_fp_restore_orig(void *); 61 extern void _elf_rtbndr_fp_fxsave(void *); 62 extern void _elf_rtbndr_fp_fxrestore(void *); 63 extern void _elf_rtbndr_fp_xsave(void *); 64 extern void _elf_rtbndr_fp_xrestore(void *); 65 66 /* 67 * Based on what the kernel has told us, go through and set up the various 68 * pointers that we'll need for elf_rtbndr for the FPU. 69 */ 70 static void 71 _setup_plt_fpu(int kind, size_t len) 72 { 73 /* 74 * If we didn't get a length for some reason, fall back to the old 75 * implementation. 76 */ 77 if (len == 0) 78 kind = -1; 79 80 switch (kind) { 81 case AT_386_FPINFO_FXSAVE: 82 _plt_fp_save = _elf_rtbndr_fp_fxsave; 83 _plt_fp_restore = _elf_rtbndr_fp_fxrestore; 84 _plt_save_size = len; 85 break; 86 /* 87 * We can treat processors that don't correctly handle the exception 88 * information in xsave the same way we do others. The information 89 * that may or may not be properly saved and restored should not be 90 * relevant to us because of the ABI. 91 */ 92 case AT_386_FPINFO_XSAVE: 93 case AT_386_FPINFO_XSAVE_AMD: 94 _plt_fp_save = _elf_rtbndr_fp_xsave; 95 _plt_fp_restore = _elf_rtbndr_fp_xrestore; 96 _plt_save_size = len; 97 break; 98 default: 99 _plt_fp_save = _elf_rtbndr_fp_save_orig; 100 _plt_fp_restore = _elf_rtbndr_fp_restore_orig; 101 /* 102 * The ABI says that 8 floating point registers are used for 103 * passing arguments (%xmm0 through %xmm7). Because these 104 * registers on some platforms may shadow the %ymm and %zmm 105 * registers, we end up needing to size this for the maximally 106 * sized register we care about, a 512-bit (64-byte) zmm 107 * register. 108 */ 109 _plt_save_size = 64 * 8; 110 break; 111 } 112 } 113 114 /* VARARGS */ 115 unsigned long 116 _setup(Boot *ebp, Dyn *ld_dyn) 117 { 118 ulong_t reladdr, relacount, ld_base = 0; 119 ulong_t relaent = 0, pltrelsz = 0; 120 ulong_t strtab, soname, interp_base = 0; 121 char *_rt_name, **_envp, **_argv; 122 int _syspagsz = 0, fd = -1; 123 uint_t _flags = 0; 124 uint_t hwcap[2] = { 0, 0 }; 125 Dyn *dyn_ptr; 126 Phdr *phdr = NULL; 127 Rt_map *lmp; 128 auxv_t *auxv, *_auxv; 129 uid_t uid = (uid_t)-1, euid = (uid_t)-1; 130 gid_t gid = (gid_t)-1, egid = (gid_t)-1; 131 char *_platform = NULL, *_execname = NULL, *_emulator = NULL; 132 int auxflags = -1, fpkind = -1; 133 size_t fpsize = 0; 134 135 /* 136 * Scan the bootstrap structure to pick up the basics. 137 */ 138 for (; ebp->eb_tag != EB_NULL; ebp++) 139 switch (ebp->eb_tag) { 140 case EB_LDSO_BASE: 141 ld_base = (unsigned long)ebp->eb_un.eb_val; 142 break; 143 case EB_ARGV: 144 _argv = (char **)ebp->eb_un.eb_ptr; 145 break; 146 case EB_ENVP: 147 _envp = (char **)ebp->eb_un.eb_ptr; 148 break; 149 case EB_AUXV: 150 _auxv = (auxv_t *)ebp->eb_un.eb_ptr; 151 break; 152 case EB_PAGESIZE: 153 _syspagsz = (int)ebp->eb_un.eb_val; 154 break; 155 } 156 157 /* 158 * Search the aux. vector for the information passed by exec. 159 */ 160 for (auxv = _auxv; auxv->a_type != AT_NULL; auxv++) { 161 switch (auxv->a_type) { 162 case AT_EXECFD: 163 /* this is the old exec that passes a file descriptor */ 164 fd = (int)auxv->a_un.a_val; 165 break; 166 case AT_FLAGS: 167 /* processor flags (MAU available, etc) */ 168 _flags = auxv->a_un.a_val; 169 break; 170 case AT_PAGESZ: 171 /* system page size */ 172 _syspagsz = (int)auxv->a_un.a_val; 173 break; 174 case AT_PHDR: 175 /* address of the segment table */ 176 phdr = (Phdr *)auxv->a_un.a_ptr; 177 break; 178 case AT_BASE: 179 /* interpreter base address */ 180 if (ld_base == 0) 181 ld_base = auxv->a_un.a_val; 182 interp_base = auxv->a_un.a_val; 183 break; 184 case AT_SUN_UID: 185 /* effective user id for the executable */ 186 euid = (uid_t)auxv->a_un.a_val; 187 break; 188 case AT_SUN_RUID: 189 /* real user id for the executable */ 190 uid = (uid_t)auxv->a_un.a_val; 191 break; 192 case AT_SUN_GID: 193 /* effective group id for the executable */ 194 egid = (gid_t)auxv->a_un.a_val; 195 break; 196 case AT_SUN_RGID: 197 /* real group id for the executable */ 198 gid = (gid_t)auxv->a_un.a_val; 199 break; 200 case AT_SUN_PLATFORM: 201 /* platform name */ 202 _platform = auxv->a_un.a_ptr; 203 break; 204 case AT_SUN_EXECNAME: 205 /* full pathname of execed object */ 206 _execname = auxv->a_un.a_ptr; 207 break; 208 case AT_SUN_AUXFLAGS: 209 /* auxiliary flags */ 210 auxflags = (int)auxv->a_un.a_val; 211 break; 212 case AT_SUN_HWCAP: 213 /* hardware capabilities */ 214 hwcap[0] = (uint_t)auxv->a_un.a_val; 215 break; 216 case AT_SUN_HWCAP2: 217 /* hardware capabilities */ 218 hwcap[1] = (uint_t)auxv->a_un.a_val; 219 break; 220 case AT_SUN_EMULATOR: 221 /* name of emulation library, if any */ 222 _emulator = auxv->a_un.a_ptr; 223 break; 224 case AT_SUN_FPTYPE: 225 fpkind = (int)auxv->a_un.a_val; 226 break; 227 case AT_SUN_FPSIZE: 228 fpsize = (size_t)auxv->a_un.a_val; 229 break; 230 } 231 } 232 233 /* 234 * Get needed info from ld.so's dynamic structure. 235 */ 236 /* LINTED */ 237 dyn_ptr = (Dyn *)((char *)ld_dyn + ld_base); 238 for (ld_dyn = dyn_ptr; ld_dyn->d_tag != DT_NULL; ld_dyn++) { 239 switch (ld_dyn->d_tag) { 240 case DT_RELA: 241 reladdr = ld_dyn->d_un.d_ptr + ld_base; 242 break; 243 case DT_RELACOUNT: 244 relacount = ld_dyn->d_un.d_val; 245 break; 246 case DT_RELAENT: 247 relaent = ld_dyn->d_un.d_val; 248 break; 249 case DT_PLTRELSZ: 250 pltrelsz = ld_dyn->d_un.d_val; 251 break; 252 case DT_STRTAB: 253 strtab = ld_dyn->d_un.d_ptr + ld_base; 254 break; 255 case DT_SONAME: 256 soname = ld_dyn->d_un.d_val; 257 break; 258 } 259 } 260 _rt_name = (char *)strtab + soname; 261 262 /* 263 * If we don't have a RELAENT, just assume the size. 264 */ 265 if (relaent == 0) 266 relaent = sizeof (Rela); 267 268 /* 269 * As all global symbol references within ld.so.1 are protected 270 * (symbolic), only RELATIVE and JMPSLOT relocations should be left 271 * to process at runtime. Process all relocations now. 272 */ 273 relacount += (pltrelsz / relaent); 274 for (; relacount; relacount--) { 275 ulong_t roffset; 276 277 roffset = ((Rela *)reladdr)->r_offset + ld_base; 278 *((ulong_t *)roffset) += ld_base + 279 ((Rela *)reladdr)->r_addend; 280 reladdr += relaent; 281 } 282 283 /* 284 * If an emulation library is being used, use that as the linker's 285 * effective executable name. The real executable is not linked by this 286 * linker. 287 */ 288 if (_emulator != NULL) { 289 _execname = _emulator; 290 rtld_flags2 |= RT_FL2_BRANDED; 291 } 292 293 /* 294 * Initialize the dyn_plt_ent_size field. It currently contains the 295 * size of the dyn_plt_template. It still needs to be aligned and have 296 * space for the 'dyn_data' area added. 297 */ 298 dyn_plt_ent_size = ROUND(dyn_plt_ent_size, M_WORD_ALIGN) + 299 sizeof (uintptr_t) + sizeof (uintptr_t) + sizeof (ulong_t) + 300 sizeof (ulong_t) + sizeof (Sym); 301 302 /* 303 * Initialize the amd64 specific PLT relocation constants based on the 304 * FP information that we have. 305 */ 306 _setup_plt_fpu(fpkind, fpsize); 307 308 /* 309 * Continue with generic startup processing. 310 */ 311 if ((lmp = setup((char **)_envp, (auxv_t *)_auxv, _flags, _platform, 312 _syspagsz, _rt_name, ld_base, interp_base, fd, phdr, 313 _execname, _argv, uid, euid, gid, egid, NULL, auxflags, 314 hwcap)) == NULL) { 315 rtldexit(&lml_main, 1); 316 } 317 318 return (LM_ENTRY_PT(lmp)()); 319 } 320