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, NULL);
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	if (strcmp(__elfN(obj_kerneltype), kfp->f_type)) {
140		printf("elf" __XSTRING(__ELF_WORD_SIZE)
141		    "_obj_loadfile: can't load module with kernel type '%s'\n",
142		    kfp->f_type);
143		err = EPERM;
144		goto oerr;
145	}
146
147	if (archsw.arch_loadaddr != NULL)
148		dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest);
149	else
150		dest = roundup(dest, PAGE_SIZE);
151
152	/*
153	 * Ok, we think we should handle this.
154	 */
155	fp = file_alloc();
156	if (fp == NULL) {
157		printf("elf" __XSTRING(__ELF_WORD_SIZE)
158		    "_obj_loadfile: cannot allocate module info\n");
159		err = EPERM;
160		goto out;
161	}
162	fp->f_name = strdup(filename);
163	fp->f_type = strdup(__elfN(obj_moduletype));
164
165	printf("%s ", filename);
166
167	fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest);
168	if (fp->f_size == 0 || fp->f_addr == 0)
169		goto ioerr;
170
171	/* save exec header as metadata */
172	file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr);
173
174	/* Load OK, return module pointer */
175	*result = (struct preloaded_file *)fp;
176	err = 0;
177	goto out;
178
179ioerr:
180	err = EIO;
181oerr:
182	file_discard(fp);
183out:
184	close(ef.fd);
185	if (ef.e_shdr != NULL)
186		free(ef.e_shdr);
187
188	return(err);
189}
190
191/*
192 * With the file (fd) open on the image, and (ehdr) containing
193 * the Elf header, load the image at (off)
194 */
195static int
196__elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
197{
198	Elf_Ehdr *hdr;
199	Elf_Shdr *shdr, *cshdr, *lshdr;
200	vm_offset_t firstaddr, lastaddr;
201	int i, nsym, res, ret, shdrbytes, symstrindex;
202
203	ret = 0;
204	firstaddr = lastaddr = (vm_offset_t)off;
205	hdr = &ef->hdr;
206	ef->off = (vm_offset_t)off;
207
208	/* Read in the section headers. */
209	shdrbytes = hdr->e_shnum * hdr->e_shentsize;
210	shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes);
211	if (shdr == NULL) {
212		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
213		    "_obj_loadimage: read section headers failed\n");
214		goto out;
215	}
216	ef->e_shdr = shdr;
217
218	/*
219	 * Decide where to load everything, but don't read it yet.
220	 * We store the load address as a non-zero sh_addr value.
221	 * Start with the code/data and bss.
222	 */
223	for (i = 0; i < hdr->e_shnum; i++)
224		shdr[i].sh_addr = 0;
225	for (i = 0; i < hdr->e_shnum; i++) {
226		if (shdr[i].sh_size == 0)
227			continue;
228		switch (shdr[i].sh_type) {
229		case SHT_PROGBITS:
230		case SHT_NOBITS:
231			lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
232			shdr[i].sh_addr = (Elf_Addr)lastaddr;
233			lastaddr += shdr[i].sh_size;
234			break;
235		}
236	}
237
238	/* Symbols. */
239	nsym = 0;
240	for (i = 0; i < hdr->e_shnum; i++) {
241		switch (shdr[i].sh_type) {
242		case SHT_SYMTAB:
243			nsym++;
244			ef->symtabindex = i;
245			shdr[i].sh_addr = (Elf_Addr)lastaddr;
246			lastaddr += shdr[i].sh_size;
247			break;
248		}
249	}
250	if (nsym != 1) {
251		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
252		    "_obj_loadimage: file has no valid symbol table\n");
253		goto out;
254	}
255	lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign);
256	shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr;
257	lastaddr += shdr[ef->symtabindex].sh_size;
258
259	symstrindex = shdr[ef->symtabindex].sh_link;
260	if (symstrindex < 0 || symstrindex >= hdr->e_shnum ||
261	    shdr[symstrindex].sh_type != SHT_STRTAB) {
262		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
263		    "_obj_loadimage: file has invalid symbol strings\n");
264		goto out;
265	}
266	lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign);
267	shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr;
268	lastaddr += shdr[symstrindex].sh_size;
269
270	/* Section names. */
271	if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum ||
272	    shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) {
273		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
274		    "_obj_loadimage: file has no section names\n");
275		goto out;
276	}
277	ef->shstrindex = hdr->e_shstrndx;
278	lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign);
279	shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr;
280	lastaddr += shdr[ef->shstrindex].sh_size;
281
282	/* Relocation tables. */
283	for (i = 0; i < hdr->e_shnum; i++) {
284		switch (shdr[i].sh_type) {
285		case SHT_REL:
286		case SHT_RELA:
287			lastaddr = roundup(lastaddr, shdr[i].sh_addralign);
288			shdr[i].sh_addr = (Elf_Addr)lastaddr;
289			lastaddr += shdr[i].sh_size;
290			break;
291		}
292	}
293
294	/* Clear the whole area, including bss regions. */
295	kern_bzero(firstaddr, lastaddr - firstaddr);
296
297	/* Figure section with the lowest file offset we haven't loaded yet. */
298	for (cshdr = NULL; /* none */; /* none */)
299	{
300		/*
301		 * Find next section to load. The complexity of this loop is
302		 * O(n^2), but with  the number of sections being typically
303		 * small, we do not care.
304		 */
305		lshdr = cshdr;
306
307		for (i = 0; i < hdr->e_shnum; i++) {
308			if (shdr[i].sh_addr == 0 ||
309			    shdr[i].sh_type == SHT_NOBITS)
310				continue;
311			/* Skip sections that were loaded already. */
312			if (lshdr != NULL &&
313			    lshdr->sh_offset >= shdr[i].sh_offset)
314				continue;
315			/* Find section with smallest offset. */
316			if (cshdr == lshdr ||
317			    cshdr->sh_offset > shdr[i].sh_offset)
318				cshdr = &shdr[i];
319		}
320
321		if (cshdr == lshdr)
322			break;
323
324		if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr,
325		    cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) {
326			printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
327			    "_obj_loadimage: read failed\n");
328			goto out;
329		}
330	}
331
332	file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr);
333
334	res = __elfN(obj_parse_modmetadata)(fp, ef);
335	if (res != 0)
336		goto out;
337
338	ret = lastaddr - firstaddr;
339	fp->f_addr = firstaddr;
340
341	printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr);
342
343out:
344	printf("\n");
345	return ret;
346}
347
348#if defined(__i386__) && __ELF_WORD_SIZE == 64
349struct mod_metadata64 {
350	int		md_version;	/* structure version MDTV_* */
351	int		md_type;	/* type of entry MDT_* */
352	u_int64_t	md_data;	/* specific data */
353	u_int64_t	md_cval;	/* common string label */
354};
355#endif
356
357int
358__elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef)
359{
360	struct mod_metadata md;
361#if defined(__i386__) && __ELF_WORD_SIZE == 64
362	struct mod_metadata64 md64;
363#endif
364	struct mod_depend *mdepend;
365	struct mod_version mver;
366	char *s;
367	int error, modcnt, minfolen;
368	Elf_Addr v, p, p_stop;
369
370	if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop,
371	    &modcnt) != 0)
372		return 0;
373
374	modcnt = 0;
375	while (p < p_stop) {
376		COPYOUT(p, &v, sizeof(v));
377		error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v));
378		if (error != 0)
379			return (error);
380#if defined(__i386__) && __ELF_WORD_SIZE == 64
381		COPYOUT(v, &md64, sizeof(md64));
382		error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64));
383		if (error != 0)
384			return (error);
385		md.md_version = md64.md_version;
386		md.md_type = md64.md_type;
387		md.md_cval = (const char *)(uintptr_t)md64.md_cval;
388		md.md_data = (void *)(uintptr_t)md64.md_data;
389#else
390		COPYOUT(v, &md, sizeof(md));
391		error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md));
392		if (error != 0)
393			return (error);
394#endif
395		p += sizeof(Elf_Addr);
396		switch(md.md_type) {
397		case MDT_DEPEND:
398			s = strdupout((vm_offset_t)md.md_cval);
399			minfolen = sizeof(*mdepend) + strlen(s) + 1;
400			mdepend = malloc(minfolen);
401			if (mdepend == NULL)
402				return ENOMEM;
403			COPYOUT((vm_offset_t)md.md_data, mdepend,
404			    sizeof(*mdepend));
405			strcpy((char*)(mdepend + 1), s);
406			free(s);
407			file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen,
408			    mdepend);
409			free(mdepend);
410			break;
411		case MDT_VERSION:
412			s = strdupout((vm_offset_t)md.md_cval);
413			COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver));
414			file_addmodule(fp, s, mver.mv_version, NULL);
415			free(s);
416			modcnt++;
417			break;
418		case MDT_MODULE:
419			break;
420		default:
421			printf("unknown type %d\n", md.md_type);
422			break;
423		}
424	}
425	return 0;
426}
427
428static int
429__elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef,
430    const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp)
431{
432	Elf_Ehdr *hdr;
433	Elf_Shdr *shdr;
434	char *p;
435	vm_offset_t shstrtab;
436	int i;
437
438	hdr = &ef->hdr;
439	shdr = ef->e_shdr;
440	shstrtab = shdr[ef->shstrindex].sh_addr;
441
442	for (i = 0; i < hdr->e_shnum; i++) {
443		if (shdr[i].sh_type != SHT_PROGBITS)
444			continue;
445		if (shdr[i].sh_name == 0)
446			continue;
447		p = strdupout(shstrtab + shdr[i].sh_name);
448		if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) {
449			*startp = shdr[i].sh_addr;
450			*stopp = shdr[i].sh_addr +  shdr[i].sh_size;
451			*countp = (*stopp - *startp) / sizeof(Elf_Addr);
452			free(p);
453			return (0);
454		}
455		free(p);
456	}
457
458	return (ESRCH);
459}
460
461/*
462 * Apply any intra-module relocations to the value. p is the load address
463 * of the value and val/len is the value to be modified. This does NOT modify
464 * the image in-place, because this is done by kern_linker later on.
465 */
466static int
467__elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p,
468    void *val, size_t len)
469{
470	Elf_Ehdr *hdr;
471	Elf_Shdr *shdr;
472	Elf_Addr off = p;
473	Elf_Addr base;
474	Elf_Rela a, *abase;
475	Elf_Rel r, *rbase;
476	int error, i, j, nrel, nrela;
477
478	hdr = &ef->hdr;
479	shdr = ef->e_shdr;
480
481	for (i = 0; i < hdr->e_shnum; i++) {
482		if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL)
483			continue;
484		base = shdr[shdr[i].sh_info].sh_addr;
485		if (base == 0 || shdr[i].sh_addr == 0)
486			continue;
487		if (off < base || off + len > base +
488		    shdr[shdr[i].sh_info].sh_size)
489			continue;
490
491		switch (shdr[i].sh_type) {
492		case SHT_RELA:
493			abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr;
494
495			nrela = shdr[i].sh_size / sizeof(Elf_Rela);
496			for (j = 0; j < nrela; j++) {
497				COPYOUT(abase + j, &a, sizeof(a));
498
499				error = __elfN(reloc)(ef, __elfN(obj_symaddr),
500				    &a, ELF_RELOC_RELA, base, off, val, len);
501				if (error != 0)
502					return (error);
503			}
504			break;
505		case SHT_REL:
506			rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr;
507
508			nrel = shdr[i].sh_size / sizeof(Elf_Rel);
509			for (j = 0; j < nrel; j++) {
510				COPYOUT(rbase + j, &r, sizeof(r));
511
512				error = __elfN(reloc)(ef, __elfN(obj_symaddr),
513				    &r, ELF_RELOC_REL, base, off, val, len);
514				if (error != 0)
515					return (error);
516			}
517			break;
518		}
519	}
520	return (0);
521}
522
523/* Look up the address of a specified symbol. */
524static Elf_Addr
525__elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx)
526{
527	Elf_Sym sym;
528	Elf_Addr base;
529	int symcnt;
530
531	symcnt = ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym);
532	if (symidx >= symcnt)
533		return (0);
534	COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym),
535	    &sym, sizeof(sym));
536	if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum)
537		return (0);
538	base = ef->e_shdr[sym.st_shndx].sh_addr;
539	if (base == 0)
540		return (0);
541	return (base + sym.st_value);
542}
543