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 */
55uint_t _plt_save_size;
56void (*_plt_fp_save)(void *);
57void (*_plt_fp_restore)(void *);
58
59extern void _elf_rtbndr_fp_save_orig(void *);
60extern void _elf_rtbndr_fp_restore_orig(void *);
61extern void _elf_rtbndr_fp_fxsave(void *);
62extern void _elf_rtbndr_fp_fxrestore(void *);
63extern void _elf_rtbndr_fp_xsave(void *);
64extern 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 */
70static 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 */
115unsigned 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