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
46 typedef Elf_Rel RELOC_TYPE;
47
48 /*
49 * Local decls.
50 */
51 void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot;
52
53 void
_dl_boot_bind(const long sp,long * dl_data,Elf_Dyn * dynp)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