xref: /netbsd-src/sys/lib/libsa/loadfile_elf32.c (revision cd22f25e6f6d1cc1f197fe8c5468a80f51d1c4e1)
1 /* $NetBSD: loadfile_elf32.c,v 1.22 2008/04/28 20:24:06 martin Exp $ */
2 
3 /*-
4  * Copyright (c) 1997 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center and by Christos Zoulas.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /* If not included by exec_elf64.c, ELFSIZE won't be defined. */
34 #ifndef ELFSIZE
35 #define	ELFSIZE	32
36 #endif
37 
38 #ifdef _STANDALONE
39 #include <lib/libsa/stand.h>
40 #include <lib/libkern/libkern.h>
41 #else
42 #include <stdio.h>
43 #include <string.h>
44 #include <errno.h>
45 #include <stdlib.h>
46 #include <unistd.h>
47 #include <fcntl.h>
48 #include <err.h>
49 #endif
50 
51 #include <sys/param.h>
52 #include <sys/exec.h>
53 
54 #include "loadfile.h"
55 
56 #if ((ELFSIZE == 32) && defined(BOOT_ELF32)) || \
57     ((ELFSIZE == 64) && defined(BOOT_ELF64))
58 
59 #define	ELFROUND	(ELFSIZE / 8)
60 
61 #ifndef _STANDALONE
62 #include "byteorder.h"
63 
64 /*
65  * Byte swapping may be necessary in the non-_STANDLONE case because
66  * we may be built with a host compiler.
67  */
68 #define	E16(f)								\
69 	f = (bo == ELFDATA2LSB) ? sa_htole16(f) : sa_htobe16(f)
70 #define	E32(f)								\
71 	f = (bo == ELFDATA2LSB) ? sa_htole32(f) : sa_htobe32(f)
72 #define	E64(f)								\
73 	f = (bo == ELFDATA2LSB) ? sa_htole64(f) : sa_htobe64(f)
74 
75 #define	I16(f)								\
76 	f = (bo == ELFDATA2LSB) ? sa_le16toh(f) : sa_be16toh(f)
77 #define	I32(f)								\
78 	f = (bo == ELFDATA2LSB) ? sa_le32toh(f) : sa_be32toh(f)
79 #define	I64(f)								\
80 	f = (bo == ELFDATA2LSB) ? sa_le64toh(f) : sa_be64toh(f)
81 
82 static void
83 internalize_ehdr(Elf_Byte bo, Elf_Ehdr *ehdr)
84 {
85 
86 #if ELFSIZE == 32
87 	I16(ehdr->e_type);
88 	I16(ehdr->e_machine);
89 	I32(ehdr->e_version);
90 	I32(ehdr->e_entry);
91 	I32(ehdr->e_phoff);
92 	I32(ehdr->e_shoff);
93 	I32(ehdr->e_flags);
94 	I16(ehdr->e_ehsize);
95 	I16(ehdr->e_phentsize);
96 	I16(ehdr->e_phnum);
97 	I16(ehdr->e_shentsize);
98 	I16(ehdr->e_shnum);
99 	I16(ehdr->e_shstrndx);
100 #elif ELFSIZE == 64
101 	I16(ehdr->e_type);
102 	I16(ehdr->e_machine);
103 	I32(ehdr->e_version);
104 	I64(ehdr->e_entry);
105 	I64(ehdr->e_phoff);
106 	I64(ehdr->e_shoff);
107 	I32(ehdr->e_flags);
108 	I16(ehdr->e_ehsize);
109 	I16(ehdr->e_phentsize);
110 	I16(ehdr->e_phnum);
111 	I16(ehdr->e_shentsize);
112 	I16(ehdr->e_shnum);
113 	I16(ehdr->e_shstrndx);
114 #else
115 #error ELFSIZE is not 32 or 64
116 #endif
117 }
118 
119 static void
120 externalize_ehdr(Elf_Byte bo, Elf_Ehdr *ehdr)
121 {
122 
123 #if ELFSIZE == 32
124 	E16(ehdr->e_type);
125 	E16(ehdr->e_machine);
126 	E32(ehdr->e_version);
127 	E32(ehdr->e_entry);
128 	E32(ehdr->e_phoff);
129 	E32(ehdr->e_shoff);
130 	E32(ehdr->e_flags);
131 	E16(ehdr->e_ehsize);
132 	E16(ehdr->e_phentsize);
133 	E16(ehdr->e_phnum);
134 	E16(ehdr->e_shentsize);
135 	E16(ehdr->e_shnum);
136 	E16(ehdr->e_shstrndx);
137 #elif ELFSIZE == 64
138 	E16(ehdr->e_type);
139 	E16(ehdr->e_machine);
140 	E32(ehdr->e_version);
141 	E64(ehdr->e_entry);
142 	E64(ehdr->e_phoff);
143 	E64(ehdr->e_shoff);
144 	E32(ehdr->e_flags);
145 	E16(ehdr->e_ehsize);
146 	E16(ehdr->e_phentsize);
147 	E16(ehdr->e_phnum);
148 	E16(ehdr->e_shentsize);
149 	E16(ehdr->e_shnum);
150 	E16(ehdr->e_shstrndx);
151 #else
152 #error ELFSIZE is not 32 or 64
153 #endif
154 }
155 
156 static void
157 internalize_phdr(Elf_Byte bo, Elf_Phdr *phdr)
158 {
159 
160 #if ELFSIZE == 32
161 	I32(phdr->p_type);
162 	I32(phdr->p_offset);
163 	I32(phdr->p_vaddr);
164 	I32(phdr->p_paddr);
165 	I32(phdr->p_filesz);
166 	I32(phdr->p_memsz);
167 	I32(phdr->p_flags);
168 	I32(phdr->p_align);
169 #elif ELFSIZE == 64
170 	I32(phdr->p_type);
171 	I32(phdr->p_offset);
172 	I64(phdr->p_vaddr);
173 	I64(phdr->p_paddr);
174 	I64(phdr->p_filesz);
175 	I64(phdr->p_memsz);
176 	I64(phdr->p_flags);
177 	I64(phdr->p_align);
178 #else
179 #error ELFSIZE is not 32 or 64
180 #endif
181 }
182 
183 static void
184 internalize_shdr(Elf_Byte bo, Elf_Shdr *shdr)
185 {
186 
187 #if ELFSIZE == 32
188 	I32(shdr->sh_name);
189 	I32(shdr->sh_type);
190 	I32(shdr->sh_flags);
191 	I32(shdr->sh_addr);
192 	I32(shdr->sh_offset);
193 	I32(shdr->sh_size);
194 	I32(shdr->sh_link);
195 	I32(shdr->sh_info);
196 	I32(shdr->sh_addralign);
197 	I32(shdr->sh_entsize);
198 #elif ELFSIZE == 64
199 	I32(shdr->sh_name);
200 	I32(shdr->sh_type);
201 	I64(shdr->sh_flags);
202 	I64(shdr->sh_addr);
203 	I64(shdr->sh_offset);
204 	I64(shdr->sh_size);
205 	I32(shdr->sh_link);
206 	I32(shdr->sh_info);
207 	I64(shdr->sh_addralign);
208 	I64(shdr->sh_entsize);
209 #else
210 #error ELFSIZE is not 32 or 64
211 #endif
212 }
213 
214 static void
215 externalize_shdr(Elf_Byte bo, Elf_Shdr *shdr)
216 {
217 
218 #if ELFSIZE == 32
219 	E32(shdr->sh_name);
220 	E32(shdr->sh_type);
221 	E32(shdr->sh_flags);
222 	E32(shdr->sh_addr);
223 	E32(shdr->sh_offset);
224 	E32(shdr->sh_size);
225 	E32(shdr->sh_link);
226 	E32(shdr->sh_info);
227 	E32(shdr->sh_addralign);
228 	E32(shdr->sh_entsize);
229 #elif ELFSIZE == 64
230 	E32(shdr->sh_name);
231 	E32(shdr->sh_type);
232 	E64(shdr->sh_flags);
233 	E64(shdr->sh_addr);
234 	E64(shdr->sh_offset);
235 	E64(shdr->sh_size);
236 	E32(shdr->sh_link);
237 	E32(shdr->sh_info);
238 	E64(shdr->sh_addralign);
239 	E64(shdr->sh_entsize);
240 #else
241 #error ELFSIZE is not 32 or 64
242 #endif
243 }
244 #else /* _STANDALONE */
245 /*
246  * Byte swapping is never necessary in the _STANDALONE case because
247  * we are being built with the target compiler.
248  */
249 #define	internalize_ehdr(bo, ehdr)	/* nothing */
250 #define	externalize_ehdr(bo, ehdr)	/* nothing */
251 
252 #define	internalize_phdr(bo, phdr)	/* nothing */
253 
254 #define	internalize_shdr(bo, shdr)	/* nothing */
255 #define	externalize_shdr(bo, shdr)	/* nothing */
256 #endif /* _STANDALONE */
257 
258 int
259 ELFNAMEEND(loadfile)(int fd, Elf_Ehdr *elf, u_long *marks, int flags)
260 {
261 	Elf_Shdr *shp;
262 	Elf_Phdr *phdr;
263 	int i, j;
264 	ssize_t sz;
265 	int first;
266 	paddr_t minp = ~0, maxp = 0, pos = 0;
267 	paddr_t offset = marks[MARK_START], shpp, elfp = 0;
268 	ssize_t nr;
269 
270 	/* some ports dont use the offset */
271 	offset = offset;
272 
273 	internalize_ehdr(elf->e_ident[EI_DATA], elf);
274 
275 	sz = elf->e_phnum * sizeof(Elf_Phdr);
276 	phdr = ALLOC(sz);
277 
278 	if (lseek(fd, elf->e_phoff, SEEK_SET) == -1)  {
279 		WARN(("lseek phdr"));
280 		goto freephdr;
281 	}
282 	nr = read(fd, phdr, sz);
283 	if (nr == -1) {
284 		WARN(("read program headers"));
285 		goto freephdr;
286 	}
287 	if (nr != sz) {
288 		errno = EIO;
289 		WARN(("read program headers"));
290 		goto freephdr;
291 	}
292 
293 	for (first = 1, i = 0; i < elf->e_phnum; i++) {
294 		internalize_phdr(elf->e_ident[EI_DATA], &phdr[i]);
295 
296 #ifndef MD_LOADSEG /* Allow processor ABI specific segment loads */
297 #define MD_LOADSEG(a) /*CONSTCOND*/0
298 #endif
299 		if (MD_LOADSEG(&phdr[i]))
300 			goto loadseg;
301 
302 
303 		if (phdr[i].p_type != PT_LOAD ||
304 		    (phdr[i].p_flags & (PF_W|PF_X)) == 0)
305 			continue;
306 
307 #define IS_TEXT(p)	(p.p_flags & PF_X)
308 #define IS_DATA(p)	(p.p_flags & PF_W)
309 #define IS_BSS(p)	(p.p_filesz < p.p_memsz)
310 		/*
311 		 * XXX: Assume first address is lowest
312 		 */
313 		if ((IS_TEXT(phdr[i]) && (flags & LOAD_TEXT)) ||
314 		    (IS_DATA(phdr[i]) && (flags & LOAD_DATA))) {
315 
316 		loadseg:
317 			if (marks[MARK_DATA] == 0 && IS_DATA(phdr[i]))
318 				marks[MARK_DATA] = LOADADDR(phdr[i].p_vaddr);
319 
320 			/* Read in segment. */
321 			PROGRESS(("%s%lu", first ? "" : "+",
322 			    (u_long)phdr[i].p_filesz));
323 
324 			if (lseek(fd, phdr[i].p_offset, SEEK_SET) == -1)  {
325 				WARN(("lseek text"));
326 				goto freephdr;
327 			}
328 			nr = READ(fd, phdr[i].p_vaddr, phdr[i].p_filesz);
329 			if (nr == -1) {
330 				WARN(("read text error"));
331 				goto freephdr;
332 			}
333 			if (nr != (ssize_t)phdr[i].p_filesz) {
334 				errno = EIO;
335 				WARN(("read text"));
336 				goto freephdr;
337 			}
338 			first = 0;
339 
340 		}
341 		if ((IS_TEXT(phdr[i]) && (flags & (LOAD_TEXT|COUNT_TEXT))) ||
342 		    (IS_DATA(phdr[i]) && (flags & (LOAD_DATA|COUNT_TEXT)))) {
343 			pos = phdr[i].p_vaddr;
344 			if (minp > pos)
345 				minp = pos;
346 			pos += phdr[i].p_filesz;
347 			if (maxp < pos)
348 				maxp = pos;
349 		}
350 
351 		/* Zero out bss. */
352 		if (IS_BSS(phdr[i]) && (flags & LOAD_BSS)) {
353 			PROGRESS(("+%lu",
354 			    (u_long)(phdr[i].p_memsz - phdr[i].p_filesz)));
355 			BZERO((phdr[i].p_vaddr + phdr[i].p_filesz),
356 			    phdr[i].p_memsz - phdr[i].p_filesz);
357 		}
358 		if (IS_BSS(phdr[i]) && (flags & (LOAD_BSS|COUNT_BSS))) {
359 			pos += phdr[i].p_memsz - phdr[i].p_filesz;
360 			if (maxp < pos)
361 				maxp = pos;
362 		}
363 	}
364 	DEALLOC(phdr, sz);
365 
366 	/*
367 	 * Copy the ELF and section headers.
368 	 */
369 	maxp = roundup(maxp, ELFROUND);
370 	if (flags & (LOAD_HDR|COUNT_HDR)) {
371 		elfp = maxp;
372 		maxp += sizeof(Elf_Ehdr);
373 	}
374 
375 	if (flags & (LOAD_SYM|COUNT_SYM)) {
376 		if (lseek(fd, elf->e_shoff, SEEK_SET) == -1)  {
377 			WARN(("lseek section headers"));
378 			return 1;
379 		}
380 		sz = elf->e_shnum * sizeof(Elf_Shdr);
381 
382 		shp = ALLOC(sz);
383 
384 		nr = read(fd, shp, sz);
385 		if (nr == -1) {
386 			WARN(("read section headers"));
387 			goto freeshp;
388 		}
389 		if (nr != sz) {
390 			errno = EIO;
391 			WARN(("read section headers"));
392 			goto freeshp;
393 		}
394 
395 		shpp = maxp;
396 		maxp += roundup(sz, ELFROUND);
397 
398 #ifndef _STANDALONE
399 		/* Internalize the section headers. */
400 		for (i = 0; i < elf->e_shnum; i++)
401 			internalize_shdr(elf->e_ident[EI_DATA], &shp[i]);
402 #endif /* ! _STANDALONE */
403 
404 		/*
405 		 * Now load the symbol sections themselves.  Make sure
406 		 * the sections are aligned. Don't bother with any
407 		 * string table that isn't referenced by a symbol
408 		 * table.
409 		 */
410 		for (first = 1, i = 0; i < elf->e_shnum; i++) {
411 			switch (shp[i].sh_type) {
412 			case SHT_STRTAB:
413 				for (j = 0; j < elf->e_shnum; j++)
414 					if (shp[j].sh_type == SHT_SYMTAB &&
415 					    shp[j].sh_link == (unsigned int)i)
416 						goto havesym;
417 				/* FALLTHROUGH */
418 			default:
419 				/* Not loading this, so zero out the offset. */
420 				shp[i].sh_offset = 0;
421 				break;
422 			havesym:
423 			case SHT_SYMTAB:
424 				if (flags & LOAD_SYM) {
425 					PROGRESS(("%s%ld", first ? " [" : "+",
426 					    (u_long)shp[i].sh_size));
427 					if (lseek(fd, shp[i].sh_offset,
428 					    SEEK_SET) == -1) {
429 						WARN(("lseek symbols"));
430 						goto freeshp;
431 					}
432 					nr = READ(fd, maxp, shp[i].sh_size);
433 					if (nr == -1) {
434 						WARN(("read symbols"));
435 						goto freeshp;
436 					}
437 					if (nr != (ssize_t)shp[i].sh_size) {
438 						errno = EIO;
439 						WARN(("read symbols"));
440 						goto freeshp;
441 					}
442 				}
443 				shp[i].sh_offset = maxp - elfp;
444 				maxp += roundup(shp[i].sh_size, ELFROUND);
445 				first = 0;
446 			}
447 			/* Since we don't load .shstrtab, zero the name. */
448 			shp[i].sh_name = 0;
449 		}
450 		if (flags & LOAD_SYM) {
451 #ifndef _STANDALONE
452 			/* Externalize the section headers. */
453 			for (i = 0; i < elf->e_shnum; i++)
454 				externalize_shdr(elf->e_ident[EI_DATA],
455 				    &shp[i]);
456 #endif /* ! _STANDALONE */
457 			BCOPY(shp, shpp, sz);
458 
459 			if (first == 0)
460 				PROGRESS(("]"));
461 		}
462 		DEALLOC(shp, sz);
463 	}
464 
465 	/*
466 	 * Frob the copied ELF header to give information relative
467 	 * to elfp.
468 	 */
469 	if (flags & LOAD_HDR) {
470 		elf->e_phoff = 0;
471 		elf->e_shoff = sizeof(Elf_Ehdr);
472 		elf->e_phentsize = 0;
473 		elf->e_phnum = 0;
474 		elf->e_shstrndx = SHN_UNDEF;
475 		externalize_ehdr(elf->e_ident[EI_DATA], elf);
476 		BCOPY(elf, elfp, sizeof(*elf));
477 		internalize_ehdr(elf->e_ident[EI_DATA], elf);
478 	}
479 
480 	marks[MARK_START] = LOADADDR(minp);
481 	marks[MARK_ENTRY] = LOADADDR(elf->e_entry);
482 	/*
483 	 * Since there can be more than one symbol section in the code
484 	 * and we need to find strtab too in order to do anything
485 	 * useful with the symbols, we just pass the whole elf
486 	 * header back and we let the kernel debugger find the
487 	 * location and number of symbols by itself.
488 	 */
489 	marks[MARK_NSYM] = 1;	/* XXX: Kernel needs >= 0 */
490 	marks[MARK_SYM] = LOADADDR(elfp);
491 	marks[MARK_END] = LOADADDR(maxp);
492 	return 0;
493 freephdr:
494 	DEALLOC(phdr, sz);
495 	return 1;
496 freeshp:
497 	DEALLOC(shp, sz);
498 	return 1;
499 }
500 
501 #endif /* (ELFSIZE == 32 && BOOT_ELF32) || (ELFSIZE == 64 && BOOT_ELF64) */
502