summaryrefslogtreecommitdiffstats
path: root/sys/kern/link_aout.c
blob: 662a4a93df23963eb1e422a338c859e8be73a48e (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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
/*-
 * Copyright (c) 1997 Doug Rabson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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 AUTHOR 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 AUTHOR 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.
 *
 *	$Id: link_aout.c,v 1.1 1997/05/07 16:05:32 dfr Exp $
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/namei.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/linker.h>
#include <a.out.h>
#include <link.h>

static int		link_aout_load_file(const char*, linker_file_t*);

static int		link_aout_lookup_symbol(linker_file_t, const char*,
						caddr_t*, size_t*);
static void		link_aout_unload(linker_file_t);

static struct linker_class_ops link_aout_class_ops = {
    link_aout_load_file,
};

static struct linker_file_ops link_aout_file_ops = {
    link_aout_lookup_symbol,
    link_aout_unload,
};

typedef struct aout_file {
    char*		address;	/* Load address */
    struct _dynamic*	dynamic;	/* Symbol table etc. */
} *aout_file_t;

static int		load_dependancies(linker_file_t lf);
static int		relocate_file(linker_file_t lf);

/*
 * The kernel symbol table starts here.
 */
extern struct _dynamic _DYNAMIC;

static void
link_aout_init(void* arg)
{
    struct _dynamic* dp = &_DYNAMIC;

    linker_add_class("a.out", NULL, &link_aout_class_ops);

    if (dp) {
	aout_file_t af;

	af = malloc(sizeof(struct aout_file), M_LINKER, M_NOWAIT);
	if (af == NULL)
	    panic("link_aout_init: Can't create linker structures for kernel");

	af->address = 0;
	af->dynamic = dp;
	linker_kernel_file =
	    linker_make_file(kernelname, af, &link_aout_file_ops);
	if (linker_kernel_file == NULL)
	    panic("link_aout_init: Can't create linker structures for kernel");
	/*
	 * XXX there must be a better way of getting these constants.
	 */
	linker_kernel_file->address = (caddr_t) 0xf0100000;
	linker_kernel_file->size = -0xf0100000;
	linker_current_file = linker_kernel_file;
    }
}

SYSINIT(link_aout, SI_SUB_KMEM, SI_ORDER_THIRD, link_aout_init, 0);

int
link_aout_load_file(const char* filename, linker_file_t* result)
{
    struct nameidata nd;
    struct vnode* file;
    struct proc* p = curproc;	/* XXX */
    int error = 0;
    int resid;
    struct iovec aiov;
    struct uio auio;
    struct exec header;
    aout_file_t af;
    linker_file_t lf;

    NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p);
    error = vn_open(&nd, FREAD, 0);
    if (error)
	return error;

    /*
     * Read the a.out header from the file.
     */
    error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) &header, sizeof header, 0,
		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
    if (error)
	goto out;

    if (N_BADMAG(header) || !(N_GETFLAG(header) & EX_DYNAMIC))
	goto out;

    /*
     * We have an a.out file, so make some space to read it in.
     */
    af = malloc(sizeof(struct aout_file), M_LINKER, M_WAITOK);
    af->address = malloc(header.a_text + header.a_data + header.a_bss,
			 M_LINKER, M_WAITOK);
    
    /*
     * Read the text and data sections and zero the bss.
     */
    error = vn_rdwr(UIO_READ, nd.ni_vp, (void*) af->address,
		    header.a_text + header.a_data, 0,
		    UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred, &resid, p);
    if (error)
	goto out;
    bzero(af->address + header.a_text + header.a_data, header.a_bss);

    /*
     * Assume _DYNAMIC is the first data item.
     */
    af->dynamic = (struct _dynamic*) (af->address + header.a_text);
    if (af->dynamic->d_version != LD_VERSION_BSD) {
	free(af->address, M_LINKER);
	free(af, M_LINKER);
	goto out;
    }
    (long) af->dynamic->d_un.d_sdt += af->address;

    lf = linker_make_file(filename, af, &link_aout_file_ops);
    if (lf == NULL) {
	free(af->address, M_LINKER);
	free(af, M_LINKER);
	error = ENOMEM;
	goto out;
    }
    lf->address = af->address;
    lf->size = header.a_text + header.a_data + header.a_bss;

    if ((error = load_dependancies(lf)) != 0
	|| (error = relocate_file(lf)) != 0) {
	linker_file_unload(lf);
	goto out;
    }

    *result = lf;

out:
    VOP_UNLOCK(nd.ni_vp, 0, p);
    vn_close(nd.ni_vp, FREAD, p->p_ucred, p);

    return error;
}

void
link_aout_unload(linker_file_t file)
{
    aout_file_t af = file->priv;

    if (af) {
	if (af->address)
	    free(af->address, M_LINKER);
	free(af, M_LINKER);
    }
}

#define AOUT_RELOC(af, type, off) (type*) ((af)->address + (off))

static int
load_dependancies(linker_file_t lf)
{
    aout_file_t af = lf->priv;
    linker_file_t lfdep;
    long off;
    struct sod* sodp;
    char* name;
    char* filename = 0;
    int error = 0;

    /*
     * All files are dependant on /kernel.
     */
    linker_kernel_file->refs++;
    linker_file_add_dependancy(lf, linker_kernel_file);

    off = LD_NEED(af->dynamic);

    /*
     * Load the dependancies.
     */
    while (off != 0) {
	sodp = AOUT_RELOC(af, struct sod, off);
	name = AOUT_RELOC(af, char, sodp->sod_name);

	/*
	 * Prepend pathname if dep is not an absolute filename.
	 */
	if (name[0] != '/') {
	    char* p;
	    filename = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
	    p = lf->filename + strlen(lf->filename) - 1;
	    while (p >= lf->filename && *p != '/')
		p--;
	    if (p >= lf->filename) {
		strncpy(filename, lf->filename, p - lf->filename);
		filename[p - lf->filename] = '\0';
		strcat(filename, "/");
		strcat(filename, name);
		name = filename;
	    }
	}
	error = linker_load_file(name, &lfdep);
	if (error)
	    goto out;
	error = linker_file_add_dependancy(lf, lfdep);
	if (error)
	    goto out;
	off = sodp->sod_next;
    }

out:
    if (filename)
	free(filename, M_TEMP);
    return error;
}

/*
 * XXX i386 dependant.
 */
static long
read_relocation(struct relocation_info* r, char* addr)
{
    int length = r->r_length;
    if (length == 0)
	return *(u_char*) addr;
    else if (length == 1)
	return *(u_short*) addr;
    else if (length == 2)
	return *(u_int*) addr;
    else
	printf("link_aout: unsupported relocation size %d\n", r->r_length);
    return 0;
}

static void
write_relocation(struct relocation_info* r, char* addr, long value)
{
    int length = r->r_length;
    if (length == 0)
	*(u_char*) addr = value;
    else if (length == 1)
	*(u_short*) addr = value;
    else if (length == 2)
	*(u_int*) addr = value;
    else
	printf("link_aout: unsupported relocation size %d\n", r->r_length);
}

static int
relocate_file(linker_file_t lf)
{
    aout_file_t af = lf->priv;
    struct relocation_info* rel;
    struct relocation_info* erel;
    struct relocation_info* r;
    struct nzlist* symbolbase;
    char* stringbase;
    struct nzlist* np;
    char* sym;
    long relocation;

    rel = AOUT_RELOC(af, struct relocation_info, LD_REL(af->dynamic));
    erel = AOUT_RELOC(af, struct relocation_info,
		      LD_REL(af->dynamic) + LD_RELSZ(af->dynamic));
    symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
    stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));

    for (r = rel; r < erel; r++) {
	char* addr;

	if (r->r_address == 0)
	    break;

	addr = AOUT_RELOC(af, char, r->r_address);
	if (r->r_extern) {
	    np = &symbolbase[r->r_symbolnum];
	    sym = &stringbase[np->nz_strx];

	    if (sym[0] != '_') {
		printf("link_aout: bad symbol name %s\n", sym);
		relocation = 0;
	    } else
		relocation = (long)
		    linker_file_lookup_symbol(lf, sym + 1,
					      np->nz_type != (N_SETV+N_EXT));
	    if (!relocation) {
		printf("link_aout: symbol %s not found\n", sym);
		return ENOENT;
	    }
	    
	    relocation += read_relocation(r, addr);

	    if (r->r_jmptable) {
		printf("link_aout: can't cope with jump table relocations\n");
		continue;
	    }

	    if (r->r_pcrel)
		relocation -= (long) af->address;

	    if (r->r_copy) {
		printf("link_aout: can't cope with copy relocations\n");
		continue;
	    }
	    
	    write_relocation(r, addr, relocation);
	} else {
	    write_relocation(r, addr,
			     (long)(read_relocation(r, addr) + af->address));
	}
	
    }

    return 0;
}

static long
symbol_hash_value(aout_file_t af, const char* name)
{
    long hashval;
    const char* p;

    hashval = '_';		/* fake a starting '_' for C symbols */
    for (p = name; *p; p++)
	hashval = (hashval << 1) + *p;

    return (hashval & 0x7fffffff) % LD_BUCKETS(af->dynamic);
}

int
link_aout_lookup_symbol(linker_file_t file, const char* name,
			caddr_t* address, size_t* size)
{
    aout_file_t af = file->priv;
    int buckets;
    long hashval;
    struct rrs_hash* hashbase;
    struct nzlist* symbolbase;
    char* stringbase;
    struct rrs_hash* hp;
    struct nzlist* np;
    char* cp;

    if (LD_BUCKETS(af->dynamic) == 0)
	return NULL;

    hashbase = AOUT_RELOC(af, struct rrs_hash, LD_HASH(af->dynamic));
    symbolbase = AOUT_RELOC(af, struct nzlist, LD_SYMBOL(af->dynamic));
    stringbase = AOUT_RELOC(af, char, LD_STRINGS(af->dynamic));

restart:
    hashval = symbol_hash_value(af, name);
    hp = &hashbase[hashval];
    if (hp->rh_symbolnum == -1)
	return ENOENT;

    while (hp) {
	np = (struct nzlist *) &symbolbase[hp->rh_symbolnum];
	cp = stringbase + np->nz_strx;
	/*
	 * Note: we fake the leading '_' for C symbols.
	 */
	if (cp[0] == '_' && !strcmp(cp + 1, name))
	    break;

	if (hp->rh_next == 0)
	    hp = NULL;
	else
	    hp = &hashbase[hp->rh_next];
    }

    if (hp == NULL)
	/*
	 * Not found.
	 */
	return ENOENT;

    /*
     * Check for an aliased symbol, whatever that is.
     */
    if (np->nz_type == N_INDR+N_EXT) {
	name = stringbase + (++np)->nz_strx + 1; /* +1 for '_' */
	goto restart;
    }

    /*
     * Check this is an actual definition of the symbol.
     */
    if (np->nz_value == 0)
	return ENOENT;

    if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) {
	if (np->nz_other == AUX_FUNC)
	    /* weak function */
	    return ENOENT;
	*address = 0;
	*size = np->nz_value;
    } else {
	*address = AOUT_RELOC(af, char, np->nz_value);
	*size = np->nz_size;
    }

    return 0;
}
OpenPOWER on IntegriCloud