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 * Copyright 2022 Oxide Computer Company 29 */ 30 31 /* 32 * amd64 specific setup routine - relocate ld.so's symbols, setup its 33 * environment, map in loadable sections of the executable. 34 * 35 * Takes base address ld.so was loaded at, address of ld.so's dynamic 36 * structure, address of process environment pointers, address of auxiliary 37 * vector and * argv[0] (process name). 38 * If errors occur, send process signal - otherwise 39 * return executable's entry point to the bootstrap routine. 40 */ 41 42 #include <signal.h> 43 #include <stdlib.h> 44 #include <sys/auxv.h> 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 #include <link.h> 48 #include <dlfcn.h> 49 #include "_rtld.h" 50 #include "_audit.h" 51 #include "msg.h" 52 53 /* 54 * Number of bytes to save for register usage. 55 */ 56 uint_t _plt_save_size; 57 void (*_plt_fp_save)(void *); 58 void (*_plt_fp_restore)(void *); 59 60 extern void _elf_rtbndr_fp_save_orig(void *); 61 extern void _elf_rtbndr_fp_restore_orig(void *); 62 extern void _elf_rtbndr_fp_fxsave(void *); 63 extern void _elf_rtbndr_fp_fxrestore(void *); 64 extern void _elf_rtbndr_fp_xsave(void *); 65 extern void _elf_rtbndr_fp_xrestore(void *); 66 67 /* 68 * Based on what the kernel has told us, go through and set up the various 69 * pointers that we'll need for elf_rtbndr for the FPU. 70 */ 71 static void 72 _setup_plt_fpu(int kind, size_t len) 73 { 74 /* 75 * If we didn't get a length for some reason, fall back to the old 76 * implementation. 77 */ 78 if (len == 0) 79 kind = -1; 80 81 switch (kind) { 82 case AT_386_FPINFO_FXSAVE: 83 _plt_fp_save = _elf_rtbndr_fp_fxsave; 84 _plt_fp_restore = _elf_rtbndr_fp_fxrestore; 85 _plt_save_size = len; 86 break; 87 /* 88 * We can treat processors that don't correctly handle the exception 89 * information in xsave the same way we do others. The information 90 * that may or may not be properly saved and restored should not be 91 * relevant to us because of the ABI. 92 */ 93 case AT_386_FPINFO_XSAVE: 94 case AT_386_FPINFO_XSAVE_AMD: 95 _plt_fp_save = _elf_rtbndr_fp_xsave; 96 _plt_fp_restore = _elf_rtbndr_fp_xrestore; 97 _plt_save_size = len; 98 break; 99 default: 100 _plt_fp_save = _elf_rtbndr_fp_save_orig; 101 _plt_fp_restore = _elf_rtbndr_fp_restore_orig; 102 /* 103 * The ABI says that 8 floating point registers are used for 104 * passing arguments (%xmm0 through %xmm7). Because these 105 * registers on some platforms may shadow the %ymm and %zmm 106 * registers, we end up needing to size this for the maximally 107 * sized register we care about, a 512-bit (64-byte) zmm 108 * register. 109 */ 110 _plt_save_size = 64 * 8; 111 break; 112 } 113 } 114 115 /* VARARGS */ 116 unsigned long 117 _setup(Boot *ebp, Dyn *ld_dyn) 118 { 119 ulong_t reladdr, relacount, ld_base = 0; 120 ulong_t relaent = 0, pltrelsz = 0; 121 ulong_t strtab, soname, interp_base = 0; 122 char *_rt_name, **_envp, **_argv; 123 int _syspagsz = 0, fd = -1; 124 uint_t _flags = 0; 125 uint_t hwcap[3] = { 0, 0, 0 }; 126 Dyn *dyn_ptr; 127 Phdr *phdr = NULL; 128 Rt_map *lmp; 129 auxv_t *auxv, *_auxv; 130 uid_t uid = (uid_t)-1, euid = (uid_t)-1; 131 gid_t gid = (gid_t)-1, egid = (gid_t)-1; 132 char *_platform = NULL, *_execname = NULL, *_emulator = NULL; 133 int auxflags = -1, fpkind = -1; 134 size_t fpsize = 0; 135 136 /* 137 * Scan the bootstrap structure to pick up the basics. 138 */ 139 for (; ebp->eb_tag != EB_NULL; ebp++) 140 switch (ebp->eb_tag) { 141 case EB_LDSO_BASE: 142 ld_base = (unsigned long)ebp->eb_un.eb_val; 143 break; 144 case EB_ARGV: 145 _argv = (char **)ebp->eb_un.eb_ptr; 146 break; 147 case EB_ENVP: 148 _envp = (char **)ebp->eb_un.eb_ptr; 149 break; 150 case EB_AUXV: 151 _auxv = (auxv_t *)ebp->eb_un.eb_ptr; 152 break; 153 case EB_PAGESIZE: 154 _syspagsz = (int)ebp->eb_un.eb_val; 155 break; 156 } 157 158 /* 159 * Search the aux. vector for the information passed by exec. 160 */ 161 for (auxv = _auxv; auxv->a_type != AT_NULL; auxv++) { 162 switch (auxv->a_type) { 163 case AT_EXECFD: 164 /* this is the old exec that passes a file descriptor */ 165 fd = (int)auxv->a_un.a_val; 166 break; 167 case AT_FLAGS: 168 /* processor flags (MAU available, etc) */ 169 _flags = auxv->a_un.a_val; 170 break; 171 case AT_PAGESZ: 172 /* system page size */ 173 _syspagsz = (int)auxv->a_un.a_val; 174 break; 175 case AT_PHDR: 176 /* address of the segment table */ 177 phdr = (Phdr *)auxv->a_un.a_ptr; 178 break; 179 case AT_BASE: 180 /* interpreter base address */ 181 if (ld_base == 0) 182 ld_base = auxv->a_un.a_val; 183 interp_base = auxv->a_un.a_val; 184 break; 185 case AT_SUN_UID: 186 /* effective user id for the executable */ 187 euid = (uid_t)auxv->a_un.a_val; 188 break; 189 case AT_SUN_RUID: 190 /* real user id for the executable */ 191 uid = (uid_t)auxv->a_un.a_val; 192 break; 193 case AT_SUN_GID: 194 /* effective group id for the executable */ 195 egid = (gid_t)auxv->a_un.a_val; 196 break; 197 case AT_SUN_RGID: 198 /* real group id for the executable */ 199 gid = (gid_t)auxv->a_un.a_val; 200 break; 201 case AT_SUN_PLATFORM: 202 /* platform name */ 203 _platform = auxv->a_un.a_ptr; 204 break; 205 case AT_SUN_EXECNAME: 206 /* full pathname of execed object */ 207 _execname = auxv->a_un.a_ptr; 208 break; 209 case AT_SUN_AUXFLAGS: 210 /* auxiliary flags */ 211 auxflags = (int)auxv->a_un.a_val; 212 break; 213 case AT_SUN_HWCAP: 214 /* hardware capabilities */ 215 hwcap[0] = (uint_t)auxv->a_un.a_val; 216 break; 217 case AT_SUN_HWCAP2: 218 /* hardware capabilities */ 219 hwcap[1] = (uint_t)auxv->a_un.a_val; 220 break; 221 case AT_SUN_HWCAP3: 222 /* hardware capabilities */ 223 hwcap[2] = (uint_t)auxv->a_un.a_val; 224 break; 225 case AT_SUN_EMULATOR: 226 /* name of emulation library, if any */ 227 _emulator = auxv->a_un.a_ptr; 228 break; 229 case AT_SUN_FPTYPE: 230 fpkind = (int)auxv->a_un.a_val; 231 break; 232 case AT_SUN_FPSIZE: 233 fpsize = (size_t)auxv->a_un.a_val; 234 break; 235 } 236 } 237 238 /* 239 * Get needed info from ld.so's dynamic structure. 240 */ 241 /* LINTED */ 242 dyn_ptr = (Dyn *)((char *)ld_dyn + ld_base); 243 for (ld_dyn = dyn_ptr; ld_dyn->d_tag != DT_NULL; ld_dyn++) { 244 switch (ld_dyn->d_tag) { 245 case DT_RELA: 246 reladdr = ld_dyn->d_un.d_ptr + ld_base; 247 break; 248 case DT_RELACOUNT: 249 relacount = ld_dyn->d_un.d_val; 250 break; 251 case DT_RELAENT: 252 relaent = ld_dyn->d_un.d_val; 253 break; 254 case DT_PLTRELSZ: 255 pltrelsz = ld_dyn->d_un.d_val; 256 break; 257 case DT_STRTAB: 258 strtab = ld_dyn->d_un.d_ptr + ld_base; 259 break; 260 case DT_SONAME: 261 soname = ld_dyn->d_un.d_val; 262 break; 263 } 264 } 265 _rt_name = (char *)strtab + soname; 266 267 /* 268 * If we don't have a RELAENT, just assume the size. 269 */ 270 if (relaent == 0) 271 relaent = sizeof (Rela); 272 273 /* 274 * As all global symbol references within ld.so.1 are protected 275 * (symbolic), only RELATIVE and JMPSLOT relocations should be left 276 * to process at runtime. Process all relocations now. 277 */ 278 relacount += (pltrelsz / relaent); 279 for (; relacount; relacount--) { 280 ulong_t roffset; 281 282 roffset = ((Rela *)reladdr)->r_offset + ld_base; 283 *((ulong_t *)roffset) += ld_base + 284 ((Rela *)reladdr)->r_addend; 285 reladdr += relaent; 286 } 287 288 /* 289 * If an emulation library is being used, use that as the linker's 290 * effective executable name. The real executable is not linked by this 291 * linker. 292 */ 293 if (_emulator != NULL) { 294 _execname = _emulator; 295 rtld_flags2 |= RT_FL2_BRANDED; 296 } 297 298 /* 299 * Initialize the dyn_plt_ent_size field. It currently contains the 300 * size of the dyn_plt_template. It still needs to be aligned and have 301 * space for the 'dyn_data' area added. 302 */ 303 dyn_plt_ent_size = ROUND(dyn_plt_ent_size, M_WORD_ALIGN) + 304 sizeof (uintptr_t) + sizeof (uintptr_t) + sizeof (ulong_t) + 305 sizeof (ulong_t) + sizeof (Sym); 306 307 /* 308 * Initialize the amd64 specific PLT relocation constants based on the 309 * FP information that we have. 310 */ 311 _setup_plt_fpu(fpkind, fpsize); 312 313 /* 314 * Continue with generic startup processing. 315 */ 316 if ((lmp = setup((char **)_envp, (auxv_t *)_auxv, _flags, _platform, 317 _syspagsz, _rt_name, ld_base, interp_base, fd, phdr, 318 _execname, _argv, uid, euid, gid, egid, auxflags, 319 hwcap)) == NULL) { 320 rtldexit(&lml_main, 1); 321 } 322 323 return (LM_ENTRY_PT(lmp)()); 324 } 325