1/*	$OpenBSD: boot_md.c,v 1.4 2022/01/17 19:45:34 guenther Exp $ */
2
3/*
4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 */
28
29/*
30 * IMPORTANT: any functions below are NOT protected by SSP.  Please
31 * do not add anything except what is required to reach GOT with
32 * an adjustment.
33 */
34
35#define	_DYN_LOADER
36
37#include <sys/exec_elf.h>
38
39#include <machine/reloc.h>
40
41#include "util.h"
42#include "archdep.h"
43
44#include "../../lib/csu/os-note-elf.h"
45
46typedef	Elf_Rel		RELOC_TYPE;
47
48/*
49 * Local decls.
50 */
51void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot;
52
53void
54_dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynp)
55{
56	AuxInfo			*auxstack;
57	long			*stack;
58	int			n, argc;
59	char			**argv, **envp;
60	long			loff;
61	unsigned		i;
62	const RELOC_TYPE	*rend;
63	const RELOC_TYPE	*dt_reloc;	/* DT_REL */
64	unsigned		dt_relocsz;	/* DT_RELSZ */
65	const Elf_Sym		*dt_symtab;
66	Elf_Addr		*dt_pltgot;
67	unsigned		dt_local_gotno, dt_gotsym, dt_symtabno;
68
69	/*
70	 * Scan argument and environment vectors. Find dynamic
71	 * data vector put after them.
72	 */
73	stack = (long *)sp;
74	argc = *stack++;
75	argv = (char **)stack;
76	envp = &argv[argc + 1];
77	stack = (long *)envp;
78	while (*stack++ != 0L)
79		;
80
81	/*
82	 * Zero out dl_data.
83	 */
84	for (n = 0; n <= AUX_entry; n++)
85		dl_data[n] = 0;
86
87	/*
88	 * Dig out auxiliary data set up by exec call. Move all known
89	 * tags to an indexed local table for easy access.
90	 */
91	for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null;
92	    auxstack++) {
93		if (auxstack->au_id > AUX_entry)
94			continue;
95		dl_data[auxstack->au_id] = auxstack->au_v;
96	}
97	loff = dl_data[AUX_base];	/* XXX assumes ld.so is linked at 0x0 */
98
99	/*
100	 * Scan the DYNAMIC section for the loader for the items we need
101	 */
102	dt_reloc = NULL;
103	dt_local_gotno = dt_gotsym = dt_symtabno = dt_relocsz = 0;
104	while (dynp->d_tag != DT_NULL) {
105		/* first the tags that are pointers to be relocated */
106		if (dynp->d_tag == DT_SYMTAB)
107			dt_symtab = (void *)(dynp->d_un.d_ptr + loff);
108		else if (dynp->d_tag == RELOC_TAG)	/* DT_REL */
109			dt_reloc = (void *)(dynp->d_un.d_ptr + loff);
110		else if (dynp->d_tag == DT_PLTGOT)
111			dt_pltgot = (void *)(dynp->d_un.d_ptr + loff);
112
113		/* Now for the tags that are just sizes or counts */
114		else if (dynp->d_tag == RELOC_TAG+1)	/* DT_RELSZ */
115			dt_relocsz = dynp->d_un.d_val;
116		else if (dynp->d_tag == DT_MIPS_LOCAL_GOTNO)
117			dt_local_gotno = dynp->d_un.d_val;
118		else if (dynp->d_tag == DT_MIPS_GOTSYM)
119			dt_gotsym = dynp->d_un.d_val;
120		else if (dynp->d_tag == DT_MIPS_SYMTABNO)
121			dt_symtabno = dynp->d_un.d_val;
122		dynp++;
123	}
124
125	rend = (RELOC_TYPE *)((char *)dt_reloc + dt_relocsz);
126	for (; dt_reloc < rend; dt_reloc++) {
127		if (ELF64_R_TYPE(dt_reloc->r_info) == R_MIPS_REL32_64) {
128			Elf_Addr *ra;
129			ra = (Elf_Addr *)(dt_reloc->r_offset + loff);
130			*ra += loff;
131		}
132	}
133
134	/* Do all local gots */
135	for (i = 2; i < dt_local_gotno; i++)
136		dt_pltgot[i] += loff;
137	dt_pltgot += dt_local_gotno;
138
139	/* Do symbol referencing gots. There should be no global... */
140	i = dt_symtabno - dt_gotsym;
141	dt_symtab += dt_gotsym;
142
143	while (i--) {
144		if (ELF64_ST_TYPE(dt_symtab->st_info) == STT_FUNC)
145			*dt_pltgot += loff;
146		else
147			*dt_pltgot = dt_symtab->st_value + loff;
148		dt_pltgot++;
149		dt_symtab++;
150	}
151}
152