aboutsummaryrefslogtreecommitdiffstats
path: root/rdoff/rdfload.c
blob: 5a7ab631617c5d53609a56ffc3e061135eedb6fd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 1996-2009 The NASM Authors - All Rights Reserved
 *   See the file AUTHORS included with the NASM distribution for
 *   the specific copyright holders.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following
 *   conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *     
 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ----------------------------------------------------------------------- */

/*
 * rdfload.c	RDOFF Object File loader library
 */

/*
 * TODO: this has been modified from previous version only in very
 * simplistic ways. Needs to be improved drastically, especially:
 *   - support for more than the 2 standard segments
 *   - support for segment relocations (hard to do in ANSI C)
 */

#include "compiler.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "rdfload.h"
#include "symtab.h"
#include "collectn.h"

extern int rdf_errno;

rdfmodule *rdfload(const char *filename)
{
    rdfmodule *f;
    int32_t bsslength = 0;
    char *hdr;
    rdfheaderrec *r;

    f = malloc(sizeof(rdfmodule));
    if (f == NULL) {
        rdf_errno = RDF_ERR_NOMEM;
        return NULL;
    }

    f->symtab = symtabNew();
    if (!f->symtab) {
        free(f);
        rdf_errno = RDF_ERR_NOMEM;
        return NULL;
    }

    /* open the file */
    if (rdfopen(&(f->f), filename)) {
        free(f);
        return NULL;
    }

    /* read in text and data segments, and header */

    f->t = malloc(f->f.seg[0].length);
    f->d = malloc(f->f.seg[1].length);  /* BSS seg allocated later */
    hdr = malloc(f->f.header_len);

    if (!f->t || !f->d || !hdr) {
        rdf_errno = RDF_ERR_NOMEM;
        rdfclose(&f->f);
        if (f->t)
            free(f->t);
        if (f->d)
            free(f->d);
        free(f);
        free(hdr);
        return NULL;
    }

    if (rdfloadseg(&f->f, RDOFF_HEADER, hdr) ||
        rdfloadseg(&f->f, RDOFF_CODE, f->t) ||
        rdfloadseg(&f->f, RDOFF_DATA, f->d)) {
        rdfclose(&f->f);
        free(f->t);
        free(f->d);
        free(f);
        free(hdr);
        return NULL;
    }

    rdfclose(&f->f);

    /* Allocate BSS segment; step through header and count BSS records */

    while ((r = rdfgetheaderrec(&f->f))) {
        if (r->type == 5)
            bsslength += r->b.amount;
    }

    f->b = malloc(bsslength);
    if (bsslength && (!f->b)) {
        free(f->t);
        free(f->d);
        free(f);
        free(hdr);
        rdf_errno = RDF_ERR_NOMEM;
        return NULL;
    }

    rdfheaderrewind(&f->f);

    f->textrel = (int32_t)(size_t)f->t;
    f->datarel = (int32_t)(size_t)f->d;
    f->bssrel  = (int32_t)(size_t)f->b;

    return f;
}

int rdf_relocate(rdfmodule * m)
{
    rdfheaderrec *r;
    Collection imports;
    symtabEnt e;
    int32_t rel;
    uint8_t *seg;

    rdfheaderrewind(&m->f);
    collection_init(&imports);

    while ((r = rdfgetheaderrec(&m->f))) {
        switch (r->type) {
        case 1:                /* Relocation record */

            /* calculate relocation factor */

            if (r->r.refseg == 0)
                rel = m->textrel;
            else if (r->r.refseg == 1)
                rel = m->datarel;
            else if (r->r.refseg == 2)
                rel = m->bssrel;
            else
                /* We currently do not support load-time linkage.
                   This should be added some time soon... */

                return 1;       /* return error code */

            if ((r->r.segment & 63) == 0)
                seg = m->t;
            else if ((r->r.segment & 63) == 1)
                seg = m->d;
            else
                continue;       /* relocation not in a loaded segment */

            /* it doesn't matter in this case that the code is non-portable,
               as the entire concept of executing a module like this is
               non-portable */
            switch (r->r.length) {
            case 1:
                seg[r->r.offset] += (char)rel;
                break;
            case 2:
                *(uint16_t *) (seg + r->r.offset) += (uint16_t) rel;
                break;
            case 4:
                *(int32_t *)(seg + r->r.offset) += rel;
                break;
            }
            break;

        case 3:                /* export record - add to symtab */
            e.segment = r->e.segment;
            e.offset = r->e.offset + (e.segment == 0 ? m->textrel :     /* 0 -> code */
                                      e.segment == 1 ? m->datarel :     /* 1 -> data */
                                      m->bssrel);       /* 2 -> bss  */
            e.flags = 0;
            e.name = malloc(strlen(r->e.label) + 1);
            if (!e.name)
                return 1;

            strcpy(e.name, r->e.label);
            symtabInsert(m->symtab, &e);
            break;

        case 6:                /* segment relocation */
            fprintf(stderr, "%s: segment relocation not supported by this "
                    "loader\n", m->f.name);
            return 1;
        }
    }
    return 0;
}