1/*-
2 * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org>
3 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
4 * Copyright (c) 1998 Peter Wemm <peter@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/exec.h>
34#include <sys/linker.h>
35#include <sys/module.h>
36#include <inttypes.h>
37#include <string.h>
38#include <machine/elf.h>
39#include <stand.h>
40#define FREEBSD_ELF
41#include <link.h>
42
43#include "bootstrap.h"
44
45#define COPYOUT(s,d,l)	archsw.arch_copyout((vm_offset_t)(s), d, l)
46
47#if defined(__i386__) && __ELF_WORD_SIZE == 64
48#undef ELF_TARG_CLASS
49#undef ELF_TARG_MACH
50#define ELF_TARG_CLASS  ELFCLASS64
51#define ELF_TARG_MACH   EM_X86_64
52#endif
53
54typedef struct elf_file {
55	Elf_Ehdr	hdr;
56	Elf_Shdr	*e_shdr;
57
58	int		symtabindex;	/* Index of symbol table */
59	int		shstrindex;	/* Index of section name string table */
60
61	int		fd;
62	vm_offset_t	off;
63} *elf_file_t;
64
65static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef,
66    u_int64_t loadaddr);
67static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef,
68    const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp);
69static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef,
70    Elf_Addr p, void *val, size_t len);
71static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp,
72    elf_file_t ef);
73static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx);
74
75const char	*__elfN(obj_kerneltype) = "elf kernel";
76const char	*__elfN(obj_moduletype) = "elf obj module";
77
78/*
79 * Attempt to load the file (file) as an ELF module.  It will be stored at
80 * (dest), and a pointer to a module structure describing the loaded object
81 * will be saved in (result).
82 */
83int
84__elfN(obj_loadfile)(char *filename, u_int64_t dest,
85    struct preloaded_file **result)
86{
87	struct preloaded_file *fp, *kfp;
88	struct elf_file	ef;
89	Elf_Ehdr *hdr;
90	int err;
91	ssize_t bytes_read;
92
93	fp = NULL;
94	bzero(&ef, sizeof(struct elf_file));
95
96	/*
97	 * Open the image, read and validate the ELF header
98	 */
99	if (filename == NULL)	/* can't handle nameless */
100		return(EFTYPE);
101	if ((ef.fd = open(filename, O_RDONLY)) == -1)
102		return(errno);
103
104	hdr = &ef.hdr;
105	bytes_read = read(ef.fd, hdr, sizeof(*hdr));
106	if (bytes_read != sizeof(*hdr)) {
107		err = EFTYPE;	/* could be EIO, but may be small file */
108		goto oerr;
109	}
110
111	/* Is it ELF? */
112	if (!IS_ELF(*hdr)) {
113		err = EFTYPE;
114		goto oerr;
115	}
116	if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||	/* Layout ? */
117	    hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
118	    hdr->e_ident[EI_VERSION] != EV_CURRENT ||	/* Version ? */
119	    hdr->e_version != EV_CURRENT ||
120	    hdr->e_machine != ELF_TARG_MACH ||		/* Machine ? */
121	    hdr->e_type != ET_REL) {
122		err = EFTYPE;
123		goto oerr;
124	}
125
126	if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 ||
127	    hdr->e_shentsize != sizeof(Elf_Shdr)) {
128		err = EFTYPE;
129		goto oerr;
130	}
131
132	kfp = file_findfile(NULL, __elfN(obj_kerneltype));
133	if (kfp == NULL) {
134		printf("elf" __XSTRING(__ELF_WORD_SIZE)
135		    "_obj_loadfile: can't load module before kernel\n");
136		err = EPERM;
137		goto oerr;
138	}
139
140	if (archsw.arch_loadaddr != NULL)
141		dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
142	else
143		dest = roundup(dest, PAGE_SIZE);
144
145	/*
146	 * Ok, we think we should handle this.
147	 */
148	fp = file_alloc();
149	if (fp == NULL) {
150		printf("elf" __XSTRING(__ELF_WORD_SIZE)
151		    "_obj_loadfile: cannot allocate module info\n");
152		err = EPERM;
153		goto out;
154	}
155	fp->f_name = strdup(filename);
156	fp->f_type = strdup(__elfN(obj_moduletype));
157
158	printf("%s ", filename);
159
160	fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
161	if (fp->f_size == 0 || fp->f_addr == 0)
162		goto ioerr;
163
164	/* save exec header as metadata */
165	file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
166
167	/* Load OK, return module pointer */
168	*result = (struct preloaded_file *)fp;
169	err = 0;
170	goto out;
171
172ioerr:
173	err = EIO;
174oerr:
175	file_discard(fp);
176out:
177	close(ef.fd);
178	if (ef.e_shdr != NULL)
179		free(ef.e_shdr);
180
181	return(err);
182}
183
184/*
185 * With the file (fd) open on the image, and (ehdr) containing
186 * the Elf header, load the image at (off)
187 */
188static int
189__elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
190{
191	Elf_Ehdr *hdr;
192	Elf_Shdr *shdr, *cshdr, *lshdr;
193	vm_offset_t firstaddr, lastaddr;
194	int i, nsym, res, ret, shdrbytes, symstrindex;
195
196	ret = 0;
197	firstaddr = lastaddr = (vm_offset_t)off;
198	hdr = &ef->hdr;
199	ef->off = (vm_offset_t)off;
200
201	/* Read in the section headers. */
202	shdrbytes = hdr->e_shnum * hdr->e_shentsize;
203	shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes);
204	if (shdr == NULL) {
205		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
206		    "_obj_loadimage: read section headers failed\n");
207		goto out;
208	}
209	ef->e_shdr = shdr;
210
211	/*
212	 * Decide where to load everything, but don't read it yet.
213	 * We store the load address as a non-zero sh_addr value.
214	 * Start with the code/data and bss.
215	 */
216	for (i = 0; i < hdr->e_shnum; i++)
217		shdr[i].sh_addr = 0;
218	for (i = 0; i < hdr->e_shnum; i++) {
219		if (shdr[i].sh_size == 0)
220			continue;
221		switch (shdr[i].sh_type) {
222		case SHT_PROGBITS:
223		case SHT_NOBITS:
224			lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
225			shdr[i].sh_addr = (Elf_Addr)lastaddr;
226			lastaddr += shdr[i].sh_size;
227			break;
228		}
229	}
230
231	/* Symbols. */
232	nsym = 0;
233	for (i = 0; i < hdr->e_shnum; i++) {
234		switch (shdr[i].sh_type) {
235		case SHT_SYMTAB:
236			nsym++;
237			ef->symtabindex = i;
238			shdr[i].sh_addr = (Elf_Addr)lastaddr;
239			lastaddr += shdr[i].sh_size;
240			break;
241		}
242	}
243	if (nsym != 1) {
244		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
245		    "_obj_loadimage: file has no valid symbol table\n");
246		goto out;
247	}
248	lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
249	shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
250	lastaddr += shdr[ef->symtabindex].sh_size;
251
252	symstrindex = shdr[ef->symtabindex].sh_link;
253	if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
254	    shdr[symstrindex].sh_type != SHT_STRTAB) {
255		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
256		    "_obj_loadimage: file has invalid symbol strings\n");
257		goto out;
258	}
259	lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
260	shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
261	lastaddr += shdr[symstrindex].sh_size;
262
263	/* Section names. */
264	if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
265	    shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
266		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
267		    "_obj_loadimage: file has no section names\n");
268		goto out;
269	}
270	ef->shstrindex = hdr->e_shstrndx;
271	lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
272	shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
273	lastaddr += shdr[ef->shstrindex].sh_size;
274
275	/* Relocation tables. */
276	for (i = 0; i < hdr->e_shnum; i++) {
277		switch (shdr[i].sh_type) {
278		case SHT_REL:
279		case SHT_RELA:
280			lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
281			shdr[i].sh_addr = (Elf_Addr)lastaddr;
282			lastaddr += shdr[i].sh_size;
283			break;
284		}
285	}
286
287	/* Clear the whole area, including bss regions. */
288	kern_bzero(firstaddr, lastaddr - firstaddr);
289
290	/* Figure section with the lowest file offset we haven't loaded yet. */
291	for (cshdr = NULL; /* none */; /* none */)
292	{
293		/*
294		 * Find next section to load. The complexity of this loop is
295		 * O(n^2), but with  the number of sections being typically
296		 * small, we do not care.
297		 */
298		lshdr = cshdr;
299
300		for (i = 0; i < hdr->e_shnum; i++) {
301			if (shdr[i].sh_addr == 0 ||
302			    shdr[i].sh_type == SHT_NOBITS)
303				continue;
304			/* Skip sections that were loaded already. */
305			if (lshdr != NULL &&
306			    lshdr->sh_offset >= shdr[i].sh_offset)
307				continue;
308			/* Find section with smallest offset. */
309			if (cshdr == lshdr ||
310			    cshdr->sh_offset > shdr[i].sh_offset)
311				cshdr = &shdr[i];
312		}
313
314		if (cshdr == lshdr)
315			break;
316
317		if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr,
318		    cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
319			printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
320			    "_obj_loadimage: read failed\n");
321			goto out;
322		}
323	}
324
325	file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
326
327	res = __elfN(obj_parse_modmetadata)(fp, ef);
328	if (res != 0)
329		goto out;
330
331	ret = lastaddr - firstaddr;
332	fp->f_addr = firstaddr;
333
334	printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
335
336out:
337	printf("\n");
338	return ret;
339}
340
341#if defined(__i386__) && __ELF_WORD_SIZE == 64
342struct mod_metadata64 {
343	int		md_version;	/* structure version MDTV_* */
344	int		md_type;	/* type of entry MDT_* */
345	u_int64_t	md_data;	/* specific data */
346	u_int64_t	md_cval;	/* common string label */
347};
348#endif
349
350int
351__elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
352{
353	struct mod_metadata md;
354#if defined(__i386__) && __ELF_WORD_SIZE == 64
355	struct mod_metadata64 md64;
356#endif
357	struct mod_depend *mdepend;
358	struct mod_version mver;
359	char *s;
360	int error, modcnt, minfolen;
361	Elf_Addr v, p, p_stop;
362
363	if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
364	    &modcnt) != 0)
365		return 0;
366
367	modcnt = 0;
368	while (p < p_stop) {
369		COPYOUT(p, &v, sizeof(v));
370		error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
371		if (error != 0)
372			return (error);
373#if defined(__i386__) && __ELF_WORD_SIZE == 64
374		COPYOUT(v, &md64, sizeof(md64));
375		error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
376		if (error != 0)
377			return (error);
378		md.md_version = md64.md_version;
379		md.md_type = md64.md_type;
380		md.md_cval = (const char *)(uintptr_t)md64.md_cval;
381		md.md_data = (void *)(uintptr_t)md64.md_data;
382#else
383		COPYOUT(v, &md, sizeof(md));
384		error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
385		if (error != 0)
386			return (error);
387#endif
388		p += sizeof(Elf_Addr);
389		switch(md.md_type) {
390		case MDT_DEPEND:
391			s = strdupout((vm_offset_t)md.md_cval);
392			minfolen = sizeof(*mdepend) + strlen(s) + 1;
393			mdepend = malloc(minfolen);
394			if (mdepend == NULL)
395				return ENOMEM;
396			COPYOUT((vm_offset_t)md.md_data, mdepend,
397			    sizeof(*mdepend));
398			strcpy((char*)(mdepend + 1), s);
399			free(s);
400			file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
401			    mdepend);
402			free(mdepend);
403			break;
404		case MDT_VERSION:
405			s = strdupout((vm_offset_t)md.md_cval);
406			COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
407			file_addmodule(fp, s, mver.mv_version, NULL);
408			free(s);
409			modcnt++;
410			break;
411		case MDT_MODULE:
412		case MDT_PNP_INFO:
413			break;
414		default:
415			printf("unknown type %d\n", md.md_type);
416			break;
417		}
418	}
419	return 0;
420}
421
422static int
423__elfN(obj_lookup_set)(struct preloaded_file *fp __unused, elf_file_t ef,
424    const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
425{
426	Elf_Ehdr *hdr;
427	Elf_Shdr *shdr;
428	char *p;
429	vm_offset_t shstrtab;
430	int i;
431
432	hdr = &ef->hdr;
433	shdr = ef->e_shdr;
434	shstrtab = shdr[ef->shstrindex].sh_addr;
435
436	for (i = 0; i < hdr->e_shnum; i++) {
437		if (shdr[i].sh_type != SHT_PROGBITS)
438			continue;
439		if (shdr[i].sh_name == 0)
440			continue;
441		p = strdupout(shstrtab + shdr[i].sh_name);
442		if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
443			*startp = shdr[i].sh_addr;
444			*stopp = shdr[i].sh_addr +  shdr[i].sh_size;
445			*countp = (*stopp - *startp) / sizeof(Elf_Addr);
446			free(p);
447			return (0);
448		}
449		free(p);
450	}
451
452	return (ESRCH);
453}
454
455/*
456 * Apply any intra-module relocations to the value. p is the load address
457 * of the value and val/len is the value to be modified. This does NOT modify
458 * the image in-place, because this is done by kern_linker later on.
459 */
460static int
461__elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
462    void *val, size_t len)
463{
464	Elf_Ehdr *hdr;
465	Elf_Shdr *shdr;
466	Elf_Addr off = p;
467	Elf_Addr base;
468	Elf_Rela a, *abase;
469	Elf_Rel r, *rbase;
470	int error, i, j, nrel, nrela;
471
472	(void)mp;
473	hdr = &ef->hdr;
474	shdr = ef->e_shdr;
475
476	for (i = 0; i < hdr->e_shnum; i++) {
477		if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
478			continue;
479		base = shdr[shdr[i].sh_info].sh_addr;
480		if (base == 0 || shdr[i].sh_addr == 0)
481			continue;
482		if (off < base || off + len > base +
483		    shdr[shdr[i].sh_info].sh_size)
484			continue;
485
486		switch (shdr[i].sh_type) {
487		case SHT_RELA:
488			abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
489
490			nrela = shdr[i].sh_size / sizeof(Elf_Rela);
491			for (j = 0; j < nrela; j++) {
492				COPYOUT(abase + j, &a, sizeof(a));
493
494				error = __elfN(reloc)(ef, __elfN(obj_symaddr),
495				    &a, ELF_RELOC_RELA, base, off, val, len);
496				if (error != 0)
497					return (error);
498			}
499			break;
500		case SHT_REL:
501			rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
502
503			nrel = shdr[i].sh_size / sizeof(Elf_Rel);
504			for (j = 0; j < nrel; j++) {
505				COPYOUT(rbase + j, &r, sizeof(r));
506
507				error = __elfN(reloc)(ef, __elfN(obj_symaddr),
508				    &r, ELF_RELOC_REL, base, off, val, len);
509				if (error != 0)
510					return (error);
511			}
512			break;
513		}
514	}
515	return (0);
516}
517
518/* Look up the address of a specified symbol. */
519static Elf_Addr
520__elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
521{
522	Elf_Sym sym;
523	Elf_Addr base;
524
525	if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym))
526		return (0);
527	COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
528	    &sym, sizeof(sym));
529	if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
530		return (0);
531	base = ef->e_shdr[sym.st_shndx].sh_addr;
532	if (base == 0)
533		return (0);
534	return (base + sym.st_value);
535}
536