xref: /openbmc/linux/fs/binfmt_flat.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
1 /****************************************************************************/
2 /*
3  *  linux/fs/binfmt_flat.c
4  *
5  *	Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com>
6  *	Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com>
7  *	Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com>
8  *	Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com>
9  *  based heavily on:
10  *
11  *  linux/fs/binfmt_aout.c:
12  *      Copyright (C) 1991, 1992, 1996  Linus Torvalds
13  *  linux/fs/binfmt_flat.c for 2.0 kernel
14  *	    Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>
15  *	JAN/99 -- coded full program relocation (gerg@snapgear.com)
16  */
17 
18 #include <linux/module.h>
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/mm.h>
22 #include <linux/mman.h>
23 #include <linux/errno.h>
24 #include <linux/signal.h>
25 #include <linux/string.h>
26 #include <linux/fs.h>
27 #include <linux/file.h>
28 #include <linux/stat.h>
29 #include <linux/fcntl.h>
30 #include <linux/ptrace.h>
31 #include <linux/user.h>
32 #include <linux/slab.h>
33 #include <linux/binfmts.h>
34 #include <linux/personality.h>
35 #include <linux/init.h>
36 #include <linux/flat.h>
37 #include <linux/syscalls.h>
38 
39 #include <asm/byteorder.h>
40 #include <asm/system.h>
41 #include <asm/uaccess.h>
42 #include <asm/unaligned.h>
43 #include <asm/cacheflush.h>
44 #include <asm/page.h>
45 
46 /****************************************************************************/
47 
48 #if 0
49 #define DEBUG 1
50 #endif
51 
52 #ifdef DEBUG
53 #define	DBG_FLT(a...)	printk(a)
54 #else
55 #define	DBG_FLT(a...)
56 #endif
57 
58 /*
59  * User data (stack, data section and bss) needs to be aligned
60  * for the same reasons as SLAB memory is, and to the same amount.
61  * Avoid duplicating architecture specific code by using the same
62  * macro as with SLAB allocation:
63  */
64 #ifdef ARCH_SLAB_MINALIGN
65 #define FLAT_DATA_ALIGN	(ARCH_SLAB_MINALIGN)
66 #else
67 #define FLAT_DATA_ALIGN	(sizeof(void *))
68 #endif
69 
70 #define RELOC_FAILED 0xff00ff01		/* Relocation incorrect somewhere */
71 #define UNLOADED_LIB 0x7ff000ff		/* Placeholder for unused library */
72 
73 struct lib_info {
74 	struct {
75 		unsigned long start_code;		/* Start of text segment */
76 		unsigned long start_data;		/* Start of data segment */
77 		unsigned long start_brk;		/* End of data segment */
78 		unsigned long text_len;			/* Length of text segment */
79 		unsigned long entry;			/* Start address for this module */
80 		unsigned long build_date;		/* When this one was compiled */
81 		short loaded;				/* Has this library been loaded? */
82 	} lib_list[MAX_SHARED_LIBS];
83 };
84 
85 #ifdef CONFIG_BINFMT_SHARED_FLAT
86 static int load_flat_shared_library(int id, struct lib_info *p);
87 #endif
88 
89 static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
90 static int flat_core_dump(struct coredump_params *cprm);
91 
92 static struct linux_binfmt flat_format = {
93 	.module		= THIS_MODULE,
94 	.load_binary	= load_flat_binary,
95 	.core_dump	= flat_core_dump,
96 	.min_coredump	= PAGE_SIZE
97 };
98 
99 /****************************************************************************/
100 /*
101  * Routine writes a core dump image in the current directory.
102  * Currently only a stub-function.
103  */
104 
105 static int flat_core_dump(struct coredump_params *cprm)
106 {
107 	printk("Process %s:%d received signr %d and should have core dumped\n",
108 			current->comm, current->pid, (int) cprm->signr);
109 	return(1);
110 }
111 
112 /****************************************************************************/
113 /*
114  * create_flat_tables() parses the env- and arg-strings in new user
115  * memory and creates the pointer tables from them, and puts their
116  * addresses on the "stack", returning the new stack pointer value.
117  */
118 
119 static unsigned long create_flat_tables(
120 	unsigned long pp,
121 	struct linux_binprm * bprm)
122 {
123 	unsigned long *argv,*envp;
124 	unsigned long * sp;
125 	char * p = (char*)pp;
126 	int argc = bprm->argc;
127 	int envc = bprm->envc;
128 	char uninitialized_var(dummy);
129 
130 	sp = (unsigned long *)p;
131 	sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
132 	sp = (unsigned long *) ((unsigned long)sp & -FLAT_DATA_ALIGN);
133 	argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
134 	envp = argv + (argc + 1);
135 
136 	if (flat_argvp_envp_on_stack()) {
137 		put_user((unsigned long) envp, sp + 2);
138 		put_user((unsigned long) argv, sp + 1);
139 	}
140 
141 	put_user(argc, sp);
142 	current->mm->arg_start = (unsigned long) p;
143 	while (argc-->0) {
144 		put_user((unsigned long) p, argv++);
145 		do {
146 			get_user(dummy, p); p++;
147 		} while (dummy);
148 	}
149 	put_user((unsigned long) NULL, argv);
150 	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
151 	while (envc-->0) {
152 		put_user((unsigned long)p, envp); envp++;
153 		do {
154 			get_user(dummy, p); p++;
155 		} while (dummy);
156 	}
157 	put_user((unsigned long) NULL, envp);
158 	current->mm->env_end = (unsigned long) p;
159 	return (unsigned long)sp;
160 }
161 
162 /****************************************************************************/
163 
164 #ifdef CONFIG_BINFMT_ZFLAT
165 
166 #include <linux/zlib.h>
167 
168 #define LBUFSIZE	4000
169 
170 /* gzip flag byte */
171 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
172 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
173 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
174 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
175 #define COMMENT      0x10 /* bit 4 set: file comment present */
176 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
177 #define RESERVED     0xC0 /* bit 6,7:   reserved */
178 
179 static int decompress_exec(
180 	struct linux_binprm *bprm,
181 	unsigned long offset,
182 	char *dst,
183 	long len,
184 	int fd)
185 {
186 	unsigned char *buf;
187 	z_stream strm;
188 	loff_t fpos;
189 	int ret, retval;
190 
191 	DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
192 
193 	memset(&strm, 0, sizeof(strm));
194 	strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
195 	if (strm.workspace == NULL) {
196 		DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
197 		return -ENOMEM;
198 	}
199 	buf = kmalloc(LBUFSIZE, GFP_KERNEL);
200 	if (buf == NULL) {
201 		DBG_FLT("binfmt_flat: no memory for read buffer\n");
202 		retval = -ENOMEM;
203 		goto out_free;
204 	}
205 
206 	/* Read in first chunk of data and parse gzip header. */
207 	fpos = offset;
208 	ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
209 
210 	strm.next_in = buf;
211 	strm.avail_in = ret;
212 	strm.total_in = 0;
213 
214 	retval = -ENOEXEC;
215 
216 	/* Check minimum size -- gzip header */
217 	if (ret < 10) {
218 		DBG_FLT("binfmt_flat: file too small?\n");
219 		goto out_free_buf;
220 	}
221 
222 	/* Check gzip magic number */
223 	if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
224 		DBG_FLT("binfmt_flat: unknown compression magic?\n");
225 		goto out_free_buf;
226 	}
227 
228 	/* Check gzip method */
229 	if (buf[2] != 8) {
230 		DBG_FLT("binfmt_flat: unknown compression method?\n");
231 		goto out_free_buf;
232 	}
233 	/* Check gzip flags */
234 	if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
235 	    (buf[3] & RESERVED)) {
236 		DBG_FLT("binfmt_flat: unknown flags?\n");
237 		goto out_free_buf;
238 	}
239 
240 	ret = 10;
241 	if (buf[3] & EXTRA_FIELD) {
242 		ret += 2 + buf[10] + (buf[11] << 8);
243 		if (unlikely(LBUFSIZE <= ret)) {
244 			DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
245 			goto out_free_buf;
246 		}
247 	}
248 	if (buf[3] & ORIG_NAME) {
249 		while (ret < LBUFSIZE && buf[ret++] != 0)
250 			;
251 		if (unlikely(LBUFSIZE == ret)) {
252 			DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
253 			goto out_free_buf;
254 		}
255 	}
256 	if (buf[3] & COMMENT) {
257 		while (ret < LBUFSIZE && buf[ret++] != 0)
258 			;
259 		if (unlikely(LBUFSIZE == ret)) {
260 			DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
261 			goto out_free_buf;
262 		}
263 	}
264 
265 	strm.next_in += ret;
266 	strm.avail_in -= ret;
267 
268 	strm.next_out = dst;
269 	strm.avail_out = len;
270 	strm.total_out = 0;
271 
272 	if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
273 		DBG_FLT("binfmt_flat: zlib init failed?\n");
274 		goto out_free_buf;
275 	}
276 
277 	while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
278 		ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
279 		if (ret <= 0)
280 			break;
281 		len -= ret;
282 
283 		strm.next_in = buf;
284 		strm.avail_in = ret;
285 		strm.total_in = 0;
286 	}
287 
288 	if (ret < 0) {
289 		DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
290 			ret, strm.msg);
291 		goto out_zlib;
292 	}
293 
294 	retval = 0;
295 out_zlib:
296 	zlib_inflateEnd(&strm);
297 out_free_buf:
298 	kfree(buf);
299 out_free:
300 	kfree(strm.workspace);
301 	return retval;
302 }
303 
304 #endif /* CONFIG_BINFMT_ZFLAT */
305 
306 /****************************************************************************/
307 
308 static unsigned long
309 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
310 {
311 	unsigned long addr;
312 	int id;
313 	unsigned long start_brk;
314 	unsigned long start_data;
315 	unsigned long text_len;
316 	unsigned long start_code;
317 
318 #ifdef CONFIG_BINFMT_SHARED_FLAT
319 	if (r == 0)
320 		id = curid;	/* Relocs of 0 are always self referring */
321 	else {
322 		id = (r >> 24) & 0xff;	/* Find ID for this reloc */
323 		r &= 0x00ffffff;	/* Trim ID off here */
324 	}
325 	if (id >= MAX_SHARED_LIBS) {
326 		printk("BINFMT_FLAT: reference 0x%x to shared library %d",
327 				(unsigned) r, id);
328 		goto failed;
329 	}
330 	if (curid != id) {
331 		if (internalp) {
332 			printk("BINFMT_FLAT: reloc address 0x%x not in same module "
333 					"(%d != %d)", (unsigned) r, curid, id);
334 			goto failed;
335 		} else if ( ! p->lib_list[id].loaded &&
336 				IS_ERR_VALUE(load_flat_shared_library(id, p))) {
337 			printk("BINFMT_FLAT: failed to load library %d", id);
338 			goto failed;
339 		}
340 		/* Check versioning information (i.e. time stamps) */
341 		if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
342 				p->lib_list[curid].build_date < p->lib_list[id].build_date) {
343 			printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
344 			goto failed;
345 		}
346 	}
347 #else
348 	id = 0;
349 #endif
350 
351 	start_brk = p->lib_list[id].start_brk;
352 	start_data = p->lib_list[id].start_data;
353 	start_code = p->lib_list[id].start_code;
354 	text_len = p->lib_list[id].text_len;
355 
356 	if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
357 		printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
358 		       (int) r,(int)(start_brk-start_code),(int)text_len);
359 		goto failed;
360 	}
361 
362 	if (r < text_len)			/* In text segment */
363 		addr = r + start_code;
364 	else					/* In data segment */
365 		addr = r - text_len + start_data;
366 
367 	/* Range checked already above so doing the range tests is redundant...*/
368 	return(addr);
369 
370 failed:
371 	printk(", killing %s!\n", current->comm);
372 	send_sig(SIGSEGV, current, 0);
373 
374 	return RELOC_FAILED;
375 }
376 
377 /****************************************************************************/
378 
379 void old_reloc(unsigned long rl)
380 {
381 #ifdef DEBUG
382 	char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
383 #endif
384 	flat_v2_reloc_t	r;
385 	unsigned long *ptr;
386 
387 	r.value = rl;
388 #if defined(CONFIG_COLDFIRE)
389 	ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
390 #else
391 	ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
392 #endif
393 
394 #ifdef DEBUG
395 	printk("Relocation of variable at DATASEG+%x "
396 		"(address %p, currently %x) into segment %s\n",
397 		r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
398 #endif
399 
400 	switch (r.reloc.type) {
401 	case OLD_FLAT_RELOC_TYPE_TEXT:
402 		*ptr += current->mm->start_code;
403 		break;
404 	case OLD_FLAT_RELOC_TYPE_DATA:
405 		*ptr += current->mm->start_data;
406 		break;
407 	case OLD_FLAT_RELOC_TYPE_BSS:
408 		*ptr += current->mm->end_data;
409 		break;
410 	default:
411 		printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
412 		break;
413 	}
414 
415 #ifdef DEBUG
416 	printk("Relocation became %x\n", (int)*ptr);
417 #endif
418 }
419 
420 /****************************************************************************/
421 
422 static int load_flat_file(struct linux_binprm * bprm,
423 		struct lib_info *libinfo, int id, unsigned long *extra_stack)
424 {
425 	struct flat_hdr * hdr;
426 	unsigned long textpos = 0, datapos = 0, result;
427 	unsigned long realdatastart = 0;
428 	unsigned long text_len, data_len, bss_len, stack_len, flags;
429 	unsigned long len, memp = 0;
430 	unsigned long memp_size, extra, rlim;
431 	unsigned long *reloc = 0, *rp;
432 	struct inode *inode;
433 	int i, rev, relocs = 0;
434 	loff_t fpos;
435 	unsigned long start_code, end_code;
436 	int ret;
437 
438 	hdr = ((struct flat_hdr *) bprm->buf);		/* exec-header */
439 	inode = bprm->file->f_path.dentry->d_inode;
440 
441 	text_len  = ntohl(hdr->data_start);
442 	data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
443 	bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
444 	stack_len = ntohl(hdr->stack_size);
445 	if (extra_stack) {
446 		stack_len += *extra_stack;
447 		*extra_stack = stack_len;
448 	}
449 	relocs    = ntohl(hdr->reloc_count);
450 	flags     = ntohl(hdr->flags);
451 	rev       = ntohl(hdr->rev);
452 
453 	if (strncmp(hdr->magic, "bFLT", 4)) {
454 		/*
455 		 * Previously, here was a printk to tell people
456 		 *   "BINFMT_FLAT: bad header magic".
457 		 * But for the kernel which also use ELF FD-PIC format, this
458 		 * error message is confusing.
459 		 * because a lot of people do not manage to produce good
460 		 */
461 		ret = -ENOEXEC;
462 		goto err;
463 	}
464 
465 	if (flags & FLAT_FLAG_KTRACE)
466 		printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
467 
468 	if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
469 		printk("BINFMT_FLAT: bad flat file version 0x%x (supported "
470 			"0x%lx and 0x%lx)\n",
471 			rev, FLAT_VERSION, OLD_FLAT_VERSION);
472 		ret = -ENOEXEC;
473 		goto err;
474 	}
475 
476 	/* Don't allow old format executables to use shared libraries */
477 	if (rev == OLD_FLAT_VERSION && id != 0) {
478 		printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
479 				(int) FLAT_VERSION);
480 		ret = -ENOEXEC;
481 		goto err;
482 	}
483 
484 	/*
485 	 * fix up the flags for the older format,  there were all kinds
486 	 * of endian hacks,  this only works for the simple cases
487 	 */
488 	if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
489 		flags = FLAT_FLAG_RAM;
490 
491 #ifndef CONFIG_BINFMT_ZFLAT
492 	if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
493 		printk("Support for ZFLAT executables is not enabled.\n");
494 		ret = -ENOEXEC;
495 		goto err;
496 	}
497 #endif
498 
499 	/*
500 	 * Check initial limits. This avoids letting people circumvent
501 	 * size limits imposed on them by creating programs with large
502 	 * arrays in the data or bss.
503 	 */
504 	rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
505 	if (rlim >= RLIM_INFINITY)
506 		rlim = ~0;
507 	if (data_len + bss_len > rlim) {
508 		ret = -ENOMEM;
509 		goto err;
510 	}
511 
512 	/* Flush all traces of the currently running executable */
513 	if (id == 0) {
514 		result = flush_old_exec(bprm);
515 		if (result) {
516 			ret = result;
517 			goto err;
518 		}
519 
520 		/* OK, This is the point of no return */
521 		set_personality(PER_LINUX_32BIT);
522 	}
523 
524 	/*
525 	 * calculate the extra space we need to map in
526 	 */
527 	extra = max_t(unsigned long, bss_len + stack_len,
528 			relocs * sizeof(unsigned long));
529 
530 	/*
531 	 * there are a couple of cases here,  the separate code/data
532 	 * case,  and then the fully copied to RAM case which lumps
533 	 * it all together.
534 	 */
535 	if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
536 		/*
537 		 * this should give us a ROM ptr,  but if it doesn't we don't
538 		 * really care
539 		 */
540 		DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
541 
542 		down_write(&current->mm->mmap_sem);
543 		textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC,
544 				  MAP_PRIVATE|MAP_EXECUTABLE, 0);
545 		up_write(&current->mm->mmap_sem);
546 		if (!textpos || IS_ERR_VALUE(textpos)) {
547 			if (!textpos)
548 				textpos = (unsigned long) -ENOMEM;
549 			printk("Unable to mmap process text, errno %d\n", (int)-textpos);
550 			ret = textpos;
551 			goto err;
552 		}
553 
554 		len = data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
555 		len = PAGE_ALIGN(len);
556 		down_write(&current->mm->mmap_sem);
557 		realdatastart = do_mmap(0, 0, len,
558 			PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
559 		up_write(&current->mm->mmap_sem);
560 
561 		if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) {
562 			if (!realdatastart)
563 				realdatastart = (unsigned long) -ENOMEM;
564 			printk("Unable to allocate RAM for process data, errno %d\n",
565 					(int)-realdatastart);
566 			do_munmap(current->mm, textpos, text_len);
567 			ret = realdatastart;
568 			goto err;
569 		}
570 		datapos = ALIGN(realdatastart +
571 				MAX_SHARED_LIBS * sizeof(unsigned long),
572 				FLAT_DATA_ALIGN);
573 
574 		DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
575 				(int)(data_len + bss_len + stack_len), (int)datapos);
576 
577 		fpos = ntohl(hdr->data_start);
578 #ifdef CONFIG_BINFMT_ZFLAT
579 		if (flags & FLAT_FLAG_GZDATA) {
580 			result = decompress_exec(bprm, fpos, (char *) datapos,
581 						 data_len + (relocs * sizeof(unsigned long)), 0);
582 		} else
583 #endif
584 		{
585 			result = bprm->file->f_op->read(bprm->file, (char *) datapos,
586 					data_len + (relocs * sizeof(unsigned long)), &fpos);
587 		}
588 		if (IS_ERR_VALUE(result)) {
589 			printk("Unable to read data+bss, errno %d\n", (int)-result);
590 			do_munmap(current->mm, textpos, text_len);
591 			do_munmap(current->mm, realdatastart, data_len + extra);
592 			ret = result;
593 			goto err;
594 		}
595 
596 		reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
597 		memp = realdatastart;
598 		memp_size = len;
599 	} else {
600 
601 		len = text_len + data_len + extra + MAX_SHARED_LIBS * sizeof(unsigned long);
602 		len = PAGE_ALIGN(len);
603 		down_write(&current->mm->mmap_sem);
604 		textpos = do_mmap(0, 0, len,
605 			PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
606 		up_write(&current->mm->mmap_sem);
607 
608 		if (!textpos || IS_ERR_VALUE(textpos)) {
609 			if (!textpos)
610 				textpos = (unsigned long) -ENOMEM;
611 			printk("Unable to allocate RAM for process text/data, errno %d\n",
612 					(int)-textpos);
613 			ret = textpos;
614 			goto err;
615 		}
616 
617 		realdatastart = textpos + ntohl(hdr->data_start);
618 		datapos = ALIGN(realdatastart +
619 				MAX_SHARED_LIBS * sizeof(unsigned long),
620 				FLAT_DATA_ALIGN);
621 
622 		reloc = (unsigned long *)
623 			(datapos + (ntohl(hdr->reloc_start) - text_len));
624 		memp = textpos;
625 		memp_size = len;
626 #ifdef CONFIG_BINFMT_ZFLAT
627 		/*
628 		 * load it all in and treat it like a RAM load from now on
629 		 */
630 		if (flags & FLAT_FLAG_GZIP) {
631 			result = decompress_exec(bprm, sizeof (struct flat_hdr),
632 					 (((char *) textpos) + sizeof (struct flat_hdr)),
633 					 (text_len + data_len + (relocs * sizeof(unsigned long))
634 						  - sizeof (struct flat_hdr)),
635 					 0);
636 			memmove((void *) datapos, (void *) realdatastart,
637 					data_len + (relocs * sizeof(unsigned long)));
638 		} else if (flags & FLAT_FLAG_GZDATA) {
639 			fpos = 0;
640 			result = bprm->file->f_op->read(bprm->file,
641 					(char *) textpos, text_len, &fpos);
642 			if (!IS_ERR_VALUE(result))
643 				result = decompress_exec(bprm, text_len, (char *) datapos,
644 						 data_len + (relocs * sizeof(unsigned long)), 0);
645 		}
646 		else
647 #endif
648 		{
649 			fpos = 0;
650 			result = bprm->file->f_op->read(bprm->file,
651 					(char *) textpos, text_len, &fpos);
652 			if (!IS_ERR_VALUE(result)) {
653 				fpos = ntohl(hdr->data_start);
654 				result = bprm->file->f_op->read(bprm->file, (char *) datapos,
655 					data_len + (relocs * sizeof(unsigned long)), &fpos);
656 			}
657 		}
658 		if (IS_ERR_VALUE(result)) {
659 			printk("Unable to read code+data+bss, errno %d\n",(int)-result);
660 			do_munmap(current->mm, textpos, text_len + data_len + extra +
661 				MAX_SHARED_LIBS * sizeof(unsigned long));
662 			ret = result;
663 			goto err;
664 		}
665 	}
666 
667 	if (flags & FLAT_FLAG_KTRACE)
668 		printk("Mapping is %x, Entry point is %x, data_start is %x\n",
669 			(int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
670 
671 	/* The main program needs a little extra setup in the task structure */
672 	start_code = textpos + sizeof (struct flat_hdr);
673 	end_code = textpos + text_len;
674 	if (id == 0) {
675 		current->mm->start_code = start_code;
676 		current->mm->end_code = end_code;
677 		current->mm->start_data = datapos;
678 		current->mm->end_data = datapos + data_len;
679 		/*
680 		 * set up the brk stuff, uses any slack left in data/bss/stack
681 		 * allocation.  We put the brk after the bss (between the bss
682 		 * and stack) like other platforms.
683 		 * Userspace code relies on the stack pointer starting out at
684 		 * an address right at the end of a page.
685 		 */
686 		current->mm->start_brk = datapos + data_len + bss_len;
687 		current->mm->brk = (current->mm->start_brk + 3) & ~3;
688 		current->mm->context.end_brk = memp + memp_size - stack_len;
689 	}
690 
691 	if (flags & FLAT_FLAG_KTRACE)
692 		printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
693 			id ? "Lib" : "Load", bprm->filename,
694 			(int) start_code, (int) end_code,
695 			(int) datapos,
696 			(int) (datapos + data_len),
697 			(int) (datapos + data_len),
698 			(int) (((datapos + data_len + bss_len) + 3) & ~3));
699 
700 	text_len -= sizeof(struct flat_hdr); /* the real code len */
701 
702 	/* Store the current module values into the global library structure */
703 	libinfo->lib_list[id].start_code = start_code;
704 	libinfo->lib_list[id].start_data = datapos;
705 	libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
706 	libinfo->lib_list[id].text_len = text_len;
707 	libinfo->lib_list[id].loaded = 1;
708 	libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
709 	libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
710 
711 	/*
712 	 * We just load the allocations into some temporary memory to
713 	 * help simplify all this mumbo jumbo
714 	 *
715 	 * We've got two different sections of relocation entries.
716 	 * The first is the GOT which resides at the begining of the data segment
717 	 * and is terminated with a -1.  This one can be relocated in place.
718 	 * The second is the extra relocation entries tacked after the image's
719 	 * data segment. These require a little more processing as the entry is
720 	 * really an offset into the image which contains an offset into the
721 	 * image.
722 	 */
723 	if (flags & FLAT_FLAG_GOTPIC) {
724 		for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
725 			unsigned long addr;
726 			if (*rp) {
727 				addr = calc_reloc(*rp, libinfo, id, 0);
728 				if (addr == RELOC_FAILED) {
729 					ret = -ENOEXEC;
730 					goto err;
731 				}
732 				*rp = addr;
733 			}
734 		}
735 	}
736 
737 	/*
738 	 * Now run through the relocation entries.
739 	 * We've got to be careful here as C++ produces relocatable zero
740 	 * entries in the constructor and destructor tables which are then
741 	 * tested for being not zero (which will always occur unless we're
742 	 * based from address zero).  This causes an endless loop as __start
743 	 * is at zero.  The solution used is to not relocate zero addresses.
744 	 * This has the negative side effect of not allowing a global data
745 	 * reference to be statically initialised to _stext (I've moved
746 	 * __start to address 4 so that is okay).
747 	 */
748 	if (rev > OLD_FLAT_VERSION) {
749 		unsigned long persistent = 0;
750 		for (i=0; i < relocs; i++) {
751 			unsigned long addr, relval;
752 
753 			/* Get the address of the pointer to be
754 			   relocated (of course, the address has to be
755 			   relocated first).  */
756 			relval = ntohl(reloc[i]);
757 			if (flat_set_persistent (relval, &persistent))
758 				continue;
759 			addr = flat_get_relocate_addr(relval);
760 			rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
761 			if (rp == (unsigned long *)RELOC_FAILED) {
762 				ret = -ENOEXEC;
763 				goto err;
764 			}
765 
766 			/* Get the pointer's value.  */
767 			addr = flat_get_addr_from_rp(rp, relval, flags,
768 							&persistent);
769 			if (addr != 0) {
770 				/*
771 				 * Do the relocation.  PIC relocs in the data section are
772 				 * already in target order
773 				 */
774 				if ((flags & FLAT_FLAG_GOTPIC) == 0)
775 					addr = ntohl(addr);
776 				addr = calc_reloc(addr, libinfo, id, 0);
777 				if (addr == RELOC_FAILED) {
778 					ret = -ENOEXEC;
779 					goto err;
780 				}
781 
782 				/* Write back the relocated pointer.  */
783 				flat_put_addr_at_rp(rp, addr, relval);
784 			}
785 		}
786 	} else {
787 		for (i=0; i < relocs; i++)
788 			old_reloc(ntohl(reloc[i]));
789 	}
790 
791 	flush_icache_range(start_code, end_code);
792 
793 	/* zero the BSS,  BRK and stack areas */
794 	memset((void*)(datapos + data_len), 0, bss_len +
795 			(memp + memp_size - stack_len -		/* end brk */
796 			libinfo->lib_list[id].start_brk) +	/* start brk */
797 			stack_len);
798 
799 	return 0;
800 err:
801 	return ret;
802 }
803 
804 
805 /****************************************************************************/
806 #ifdef CONFIG_BINFMT_SHARED_FLAT
807 
808 /*
809  * Load a shared library into memory.  The library gets its own data
810  * segment (including bss) but not argv/argc/environ.
811  */
812 
813 static int load_flat_shared_library(int id, struct lib_info *libs)
814 {
815 	struct linux_binprm bprm;
816 	int res;
817 	char buf[16];
818 
819 	/* Create the file name */
820 	sprintf(buf, "/lib/lib%d.so", id);
821 
822 	/* Open the file up */
823 	bprm.filename = buf;
824 	bprm.file = open_exec(bprm.filename);
825 	res = PTR_ERR(bprm.file);
826 	if (IS_ERR(bprm.file))
827 		return res;
828 
829 	bprm.cred = prepare_exec_creds();
830 	res = -ENOMEM;
831 	if (!bprm.cred)
832 		goto out;
833 
834 	res = prepare_binprm(&bprm);
835 
836 	if (!IS_ERR_VALUE(res))
837 		res = load_flat_file(&bprm, libs, id, NULL);
838 
839 	abort_creds(bprm.cred);
840 
841 out:
842 	allow_write_access(bprm.file);
843 	fput(bprm.file);
844 
845 	return(res);
846 }
847 
848 #endif /* CONFIG_BINFMT_SHARED_FLAT */
849 /****************************************************************************/
850 
851 /*
852  * These are the functions used to load flat style executables and shared
853  * libraries.  There is no binary dependent code anywhere else.
854  */
855 
856 static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
857 {
858 	struct lib_info libinfo;
859 	unsigned long p = bprm->p;
860 	unsigned long stack_len;
861 	unsigned long start_addr;
862 	unsigned long *sp;
863 	int res;
864 	int i, j;
865 
866 	memset(&libinfo, 0, sizeof(libinfo));
867 	/*
868 	 * We have to add the size of our arguments to our stack size
869 	 * otherwise it's too easy for users to create stack overflows
870 	 * by passing in a huge argument list.  And yes,  we have to be
871 	 * pedantic and include space for the argv/envp array as it may have
872 	 * a lot of entries.
873 	 */
874 #define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
875 	stack_len = TOP_OF_ARGS - bprm->p;             /* the strings */
876 	stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
877 	stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
878 	stack_len += FLAT_DATA_ALIGN - 1;  /* reserve for upcoming alignment */
879 
880 	res = load_flat_file(bprm, &libinfo, 0, &stack_len);
881 	if (IS_ERR_VALUE(res))
882 		return res;
883 
884 	/* Update data segment pointers for all libraries */
885 	for (i=0; i<MAX_SHARED_LIBS; i++)
886 		if (libinfo.lib_list[i].loaded)
887 			for (j=0; j<MAX_SHARED_LIBS; j++)
888 				(-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
889 					(libinfo.lib_list[j].loaded)?
890 						libinfo.lib_list[j].start_data:UNLOADED_LIB;
891 
892 	install_exec_creds(bprm);
893  	current->flags &= ~PF_FORKNOEXEC;
894 
895 	set_binfmt(&flat_format);
896 
897 	p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
898 	DBG_FLT("p=%x\n", (int)p);
899 
900 	/* copy the arg pages onto the stack, this could be more efficient :-) */
901 	for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
902 		* (char *) --p =
903 			((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
904 
905 	sp = (unsigned long *) create_flat_tables(p, bprm);
906 
907 	/* Fake some return addresses to ensure the call chain will
908 	 * initialise library in order for us.  We are required to call
909 	 * lib 1 first, then 2, ... and finally the main program (id 0).
910 	 */
911 	start_addr = libinfo.lib_list[0].entry;
912 
913 #ifdef CONFIG_BINFMT_SHARED_FLAT
914 	for (i = MAX_SHARED_LIBS-1; i>0; i--) {
915 		if (libinfo.lib_list[i].loaded) {
916 			/* Push previos first to call address */
917 			--sp;	put_user(start_addr, sp);
918 			start_addr = libinfo.lib_list[i].entry;
919 		}
920 	}
921 #endif
922 
923 	/* Stash our initial stack pointer into the mm structure */
924 	current->mm->start_stack = (unsigned long )sp;
925 
926 #ifdef FLAT_PLAT_INIT
927 	FLAT_PLAT_INIT(regs);
928 #endif
929 	DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
930 		(int)regs, (int)start_addr, (int)current->mm->start_stack);
931 
932 	start_thread(regs, start_addr, current->mm->start_stack);
933 
934 	return 0;
935 }
936 
937 /****************************************************************************/
938 
939 static int __init init_flat_binfmt(void)
940 {
941 	return register_binfmt(&flat_format);
942 }
943 
944 /****************************************************************************/
945 
946 core_initcall(init_flat_binfmt);
947 
948 /****************************************************************************/
949