xref: /openbmc/linux/fs/binfmt_flat.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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/config.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/mm.h>
23 #include <linux/mman.h>
24 #include <linux/a.out.h>
25 #include <linux/errno.h>
26 #include <linux/signal.h>
27 #include <linux/string.h>
28 #include <linux/fs.h>
29 #include <linux/file.h>
30 #include <linux/stat.h>
31 #include <linux/fcntl.h>
32 #include <linux/ptrace.h>
33 #include <linux/user.h>
34 #include <linux/slab.h>
35 #include <linux/binfmts.h>
36 #include <linux/personality.h>
37 #include <linux/init.h>
38 #include <linux/flat.h>
39 
40 #include <asm/byteorder.h>
41 #include <asm/system.h>
42 #include <asm/uaccess.h>
43 #include <asm/unaligned.h>
44 #include <asm/cacheflush.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 #define RELOC_FAILED 0xff00ff01		/* Relocation incorrect somewhere */
59 #define UNLOADED_LIB 0x7ff000ff		/* Placeholder for unused library */
60 
61 struct lib_info {
62 	struct {
63 		unsigned long start_code;		/* Start of text segment */
64 		unsigned long start_data;		/* Start of data segment */
65 		unsigned long start_brk;		/* End of data segment */
66 		unsigned long text_len;			/* Length of text segment */
67 		unsigned long entry;			/* Start address for this module */
68 		unsigned long build_date;		/* When this one was compiled */
69 		short loaded;				/* Has this library been loaded? */
70 	} lib_list[MAX_SHARED_LIBS];
71 };
72 
73 #ifdef CONFIG_BINFMT_SHARED_FLAT
74 static int load_flat_shared_library(int id, struct lib_info *p);
75 #endif
76 
77 static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
78 static int flat_core_dump(long signr, struct pt_regs * regs, struct file *file);
79 
80 extern void dump_thread(struct pt_regs *, struct user *);
81 
82 static struct linux_binfmt flat_format = {
83 	.module		= THIS_MODULE,
84 	.load_binary	= load_flat_binary,
85 	.core_dump	= flat_core_dump,
86 	.min_coredump	= PAGE_SIZE
87 };
88 
89 /****************************************************************************/
90 /*
91  * Routine writes a core dump image in the current directory.
92  * Currently only a stub-function.
93  */
94 
95 static int flat_core_dump(long signr, struct pt_regs * regs, struct file *file)
96 {
97 	printk("Process %s:%d received signr %d and should have core dumped\n",
98 			current->comm, current->pid, (int) signr);
99 	return(1);
100 }
101 
102 /****************************************************************************/
103 /*
104  * create_flat_tables() parses the env- and arg-strings in new user
105  * memory and creates the pointer tables from them, and puts their
106  * addresses on the "stack", returning the new stack pointer value.
107  */
108 
109 static unsigned long create_flat_tables(
110 	unsigned long pp,
111 	struct linux_binprm * bprm)
112 {
113 	unsigned long *argv,*envp;
114 	unsigned long * sp;
115 	char * p = (char*)pp;
116 	int argc = bprm->argc;
117 	int envc = bprm->envc;
118 	char dummy;
119 
120 	sp = (unsigned long *) ((-(unsigned long)sizeof(char *))&(unsigned long) p);
121 
122 	sp -= envc+1;
123 	envp = sp;
124 	sp -= argc+1;
125 	argv = sp;
126 
127 	flat_stack_align(sp);
128 	if (flat_argvp_envp_on_stack()) {
129 		--sp; put_user((unsigned long) envp, sp);
130 		--sp; put_user((unsigned long) argv, sp);
131 	}
132 
133 	put_user(argc,--sp);
134 	current->mm->arg_start = (unsigned long) p;
135 	while (argc-->0) {
136 		put_user((unsigned long) p, argv++);
137 		do {
138 			get_user(dummy, p); p++;
139 		} while (dummy);
140 	}
141 	put_user((unsigned long) NULL, argv);
142 	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
143 	while (envc-->0) {
144 		put_user((unsigned long)p, envp); envp++;
145 		do {
146 			get_user(dummy, p); p++;
147 		} while (dummy);
148 	}
149 	put_user((unsigned long) NULL, envp);
150 	current->mm->env_end = (unsigned long) p;
151 	return (unsigned long)sp;
152 }
153 
154 /****************************************************************************/
155 
156 #ifdef CONFIG_BINFMT_ZFLAT
157 
158 #include <linux/zlib.h>
159 
160 #define LBUFSIZE	4000
161 
162 /* gzip flag byte */
163 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ASCII text */
164 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
165 #define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
166 #define ORIG_NAME    0x08 /* bit 3 set: original file name present */
167 #define COMMENT      0x10 /* bit 4 set: file comment present */
168 #define ENCRYPTED    0x20 /* bit 5 set: file is encrypted */
169 #define RESERVED     0xC0 /* bit 6,7:   reserved */
170 
171 static int decompress_exec(
172 	struct linux_binprm *bprm,
173 	unsigned long offset,
174 	char *dst,
175 	long len,
176 	int fd)
177 {
178 	unsigned char *buf;
179 	z_stream strm;
180 	loff_t fpos;
181 	int ret, retval;
182 
183 	DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
184 
185 	memset(&strm, 0, sizeof(strm));
186 	strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
187 	if (strm.workspace == NULL) {
188 		DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
189 		return -ENOMEM;
190 	}
191 	buf = kmalloc(LBUFSIZE, GFP_KERNEL);
192 	if (buf == NULL) {
193 		DBG_FLT("binfmt_flat: no memory for read buffer\n");
194 		retval = -ENOMEM;
195 		goto out_free;
196 	}
197 
198 	/* Read in first chunk of data and parse gzip header. */
199 	fpos = offset;
200 	ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
201 
202 	strm.next_in = buf;
203 	strm.avail_in = ret;
204 	strm.total_in = 0;
205 
206 	retval = -ENOEXEC;
207 
208 	/* Check minimum size -- gzip header */
209 	if (ret < 10) {
210 		DBG_FLT("binfmt_flat: file too small?\n");
211 		goto out_free_buf;
212 	}
213 
214 	/* Check gzip magic number */
215 	if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
216 		DBG_FLT("binfmt_flat: unknown compression magic?\n");
217 		goto out_free_buf;
218 	}
219 
220 	/* Check gzip method */
221 	if (buf[2] != 8) {
222 		DBG_FLT("binfmt_flat: unknown compression method?\n");
223 		goto out_free_buf;
224 	}
225 	/* Check gzip flags */
226 	if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
227 	    (buf[3] & RESERVED)) {
228 		DBG_FLT("binfmt_flat: unknown flags?\n");
229 		goto out_free_buf;
230 	}
231 
232 	ret = 10;
233 	if (buf[3] & EXTRA_FIELD) {
234 		ret += 2 + buf[10] + (buf[11] << 8);
235 		if (unlikely(LBUFSIZE == ret)) {
236 			DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
237 			goto out_free_buf;
238 		}
239 	}
240 	if (buf[3] & ORIG_NAME) {
241 		for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
242 			;
243 		if (unlikely(LBUFSIZE == ret)) {
244 			DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
245 			goto out_free_buf;
246 		}
247 	}
248 	if (buf[3] & COMMENT) {
249 		for (;  ret < LBUFSIZE && (buf[ret] != 0); ret++)
250 			;
251 		if (unlikely(LBUFSIZE == ret)) {
252 			DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
253 			goto out_free_buf;
254 		}
255 	}
256 
257 	strm.next_in += ret;
258 	strm.avail_in -= ret;
259 
260 	strm.next_out = dst;
261 	strm.avail_out = len;
262 	strm.total_out = 0;
263 
264 	if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
265 		DBG_FLT("binfmt_flat: zlib init failed?\n");
266 		goto out_free_buf;
267 	}
268 
269 	while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
270 		ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
271 		if (ret <= 0)
272 			break;
273 		if (ret >= (unsigned long) -4096)
274 			break;
275 		len -= ret;
276 
277 		strm.next_in = buf;
278 		strm.avail_in = ret;
279 		strm.total_in = 0;
280 	}
281 
282 	if (ret < 0) {
283 		DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
284 			ret, strm.msg);
285 		goto out_zlib;
286 	}
287 
288 	retval = 0;
289 out_zlib:
290 	zlib_inflateEnd(&strm);
291 out_free_buf:
292 	kfree(buf);
293 out_free:
294 	kfree(strm.workspace);
295 out:
296 	return retval;
297 }
298 
299 #endif /* CONFIG_BINFMT_ZFLAT */
300 
301 /****************************************************************************/
302 
303 static unsigned long
304 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
305 {
306 	unsigned long addr;
307 	int id;
308 	unsigned long start_brk;
309 	unsigned long start_data;
310 	unsigned long text_len;
311 	unsigned long start_code;
312 
313 #ifdef CONFIG_BINFMT_SHARED_FLAT
314 	if (r == 0)
315 		id = curid;	/* Relocs of 0 are always self referring */
316 	else {
317 		id = (r >> 24) & 0xff;	/* Find ID for this reloc */
318 		r &= 0x00ffffff;	/* Trim ID off here */
319 	}
320 	if (id >= MAX_SHARED_LIBS) {
321 		printk("BINFMT_FLAT: reference 0x%x to shared library %d",
322 				(unsigned) r, id);
323 		goto failed;
324 	}
325 	if (curid != id) {
326 		if (internalp) {
327 			printk("BINFMT_FLAT: reloc address 0x%x not in same module "
328 					"(%d != %d)", (unsigned) r, curid, id);
329 			goto failed;
330 		} else if ( ! p->lib_list[id].loaded &&
331 				load_flat_shared_library(id, p) > (unsigned long) -4096) {
332 			printk("BINFMT_FLAT: failed to load library %d", id);
333 			goto failed;
334 		}
335 		/* Check versioning information (i.e. time stamps) */
336 		if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
337 				p->lib_list[curid].build_date < p->lib_list[id].build_date) {
338 			printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
339 			goto failed;
340 		}
341 	}
342 #else
343 	id = 0;
344 #endif
345 
346 	start_brk = p->lib_list[id].start_brk;
347 	start_data = p->lib_list[id].start_data;
348 	start_code = p->lib_list[id].start_code;
349 	text_len = p->lib_list[id].text_len;
350 
351 	if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
352 		printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
353 		       (int) r,(int)(start_brk-start_code),(int)text_len);
354 		goto failed;
355 	}
356 
357 	if (r < text_len)			/* In text segment */
358 		addr = r + start_code;
359 	else					/* In data segment */
360 		addr = r - text_len + start_data;
361 
362 	/* Range checked already above so doing the range tests is redundant...*/
363 	return(addr);
364 
365 failed:
366 	printk(", killing %s!\n", current->comm);
367 	send_sig(SIGSEGV, current, 0);
368 
369 	return RELOC_FAILED;
370 }
371 
372 /****************************************************************************/
373 
374 void old_reloc(unsigned long rl)
375 {
376 #ifdef DEBUG
377 	char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
378 #endif
379 	flat_v2_reloc_t	r;
380 	unsigned long *ptr;
381 
382 	r.value = rl;
383 #if defined(CONFIG_COLDFIRE)
384 	ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
385 #else
386 	ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
387 #endif
388 
389 #ifdef DEBUG
390 	printk("Relocation of variable at DATASEG+%x "
391 		"(address %p, currently %x) into segment %s\n",
392 		r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
393 #endif
394 
395 	switch (r.reloc.type) {
396 	case OLD_FLAT_RELOC_TYPE_TEXT:
397 		*ptr += current->mm->start_code;
398 		break;
399 	case OLD_FLAT_RELOC_TYPE_DATA:
400 		*ptr += current->mm->start_data;
401 		break;
402 	case OLD_FLAT_RELOC_TYPE_BSS:
403 		*ptr += current->mm->end_data;
404 		break;
405 	default:
406 		printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
407 		break;
408 	}
409 
410 #ifdef DEBUG
411 	printk("Relocation became %x\n", (int)*ptr);
412 #endif
413 }
414 
415 /****************************************************************************/
416 
417 static int load_flat_file(struct linux_binprm * bprm,
418 		struct lib_info *libinfo, int id, unsigned long *extra_stack)
419 {
420 	struct flat_hdr * hdr;
421 	unsigned long textpos = 0, datapos = 0, result;
422 	unsigned long realdatastart = 0;
423 	unsigned long text_len, data_len, bss_len, stack_len, flags;
424 	unsigned long memp = 0; /* for finding the brk area */
425 	unsigned long extra, rlim;
426 	unsigned long *reloc = 0, *rp;
427 	struct inode *inode;
428 	int i, rev, relocs = 0;
429 	loff_t fpos;
430 	unsigned long start_code, end_code;
431 
432 	hdr = ((struct flat_hdr *) bprm->buf);		/* exec-header */
433 	inode = bprm->file->f_dentry->d_inode;
434 
435 	text_len  = ntohl(hdr->data_start);
436 	data_len  = ntohl(hdr->data_end) - ntohl(hdr->data_start);
437 	bss_len   = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
438 	stack_len = ntohl(hdr->stack_size);
439 	if (extra_stack) {
440 		stack_len += *extra_stack;
441 		*extra_stack = stack_len;
442 	}
443 	relocs    = ntohl(hdr->reloc_count);
444 	flags     = ntohl(hdr->flags);
445 	rev       = ntohl(hdr->rev);
446 
447 	if (flags & FLAT_FLAG_KTRACE)
448 		printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
449 
450 	if (strncmp(hdr->magic, "bFLT", 4) ||
451 			(rev != FLAT_VERSION && rev != OLD_FLAT_VERSION)) {
452 		/*
453 		 * because a lot of people do not manage to produce good
454 		 * flat binaries,  we leave this printk to help them realise
455 		 * the problem.  We only print the error if its not a script file
456 		 */
457 		if (strncmp(hdr->magic, "#!", 2))
458 			printk("BINFMT_FLAT: bad magic/rev (0x%x, need 0x%x)\n",
459 					rev, (int) FLAT_VERSION);
460 		return -ENOEXEC;
461 	}
462 
463 	/* Don't allow old format executables to use shared libraries */
464 	if (rev == OLD_FLAT_VERSION && id != 0) {
465 		printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
466 				(int) FLAT_VERSION);
467 		return -ENOEXEC;
468 	}
469 
470 	/*
471 	 * fix up the flags for the older format,  there were all kinds
472 	 * of endian hacks,  this only works for the simple cases
473 	 */
474 	if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
475 		flags = FLAT_FLAG_RAM;
476 
477 #ifndef CONFIG_BINFMT_ZFLAT
478 	if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
479 		printk("Support for ZFLAT executables is not enabled.\n");
480 		return -ENOEXEC;
481 	}
482 #endif
483 
484 	/*
485 	 * Check initial limits. This avoids letting people circumvent
486 	 * size limits imposed on them by creating programs with large
487 	 * arrays in the data or bss.
488 	 */
489 	rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
490 	if (rlim >= RLIM_INFINITY)
491 		rlim = ~0;
492 	if (data_len + bss_len > rlim)
493 		return -ENOMEM;
494 
495 	/* Flush all traces of the currently running executable */
496 	if (id == 0) {
497 		result = flush_old_exec(bprm);
498 		if (result)
499 			return result;
500 
501 		/* OK, This is the point of no return */
502 		set_personality(PER_LINUX);
503 	}
504 
505 	/*
506 	 * calculate the extra space we need to map in
507 	 */
508 	extra = max(bss_len + stack_len, relocs * sizeof(unsigned long));
509 
510 	/*
511 	 * there are a couple of cases here,  the separate code/data
512 	 * case,  and then the fully copied to RAM case which lumps
513 	 * it all together.
514 	 */
515 	if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
516 		/*
517 		 * this should give us a ROM ptr,  but if it doesn't we don't
518 		 * really care
519 		 */
520 		DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
521 
522 		down_write(&current->mm->mmap_sem);
523 		textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE, 0);
524 		up_write(&current->mm->mmap_sem);
525 		if (!textpos  || textpos >= (unsigned long) -4096) {
526 			if (!textpos)
527 				textpos = (unsigned long) -ENOMEM;
528 			printk("Unable to mmap process text, errno %d\n", (int)-textpos);
529 			return(textpos);
530 		}
531 
532 		down_write(&current->mm->mmap_sem);
533 		realdatastart = do_mmap(0, 0, data_len + extra +
534 				MAX_SHARED_LIBS * sizeof(unsigned long),
535 				PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
536 		up_write(&current->mm->mmap_sem);
537 
538 		if (realdatastart == 0 || realdatastart >= (unsigned long)-4096) {
539 			if (!realdatastart)
540 				realdatastart = (unsigned long) -ENOMEM;
541 			printk("Unable to allocate RAM for process data, errno %d\n",
542 					(int)-datapos);
543 			do_munmap(current->mm, textpos, text_len);
544 			return realdatastart;
545 		}
546 		datapos = realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long);
547 
548 		DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
549 				(int)(data_len + bss_len + stack_len), (int)datapos);
550 
551 		fpos = ntohl(hdr->data_start);
552 #ifdef CONFIG_BINFMT_ZFLAT
553 		if (flags & FLAT_FLAG_GZDATA) {
554 			result = decompress_exec(bprm, fpos, (char *) datapos,
555 						 data_len + (relocs * sizeof(unsigned long)), 0);
556 		} else
557 #endif
558 		{
559 			result = bprm->file->f_op->read(bprm->file, (char *) datapos,
560 					data_len + (relocs * sizeof(unsigned long)), &fpos);
561 		}
562 		if (result >= (unsigned long)-4096) {
563 			printk("Unable to read data+bss, errno %d\n", (int)-result);
564 			do_munmap(current->mm, textpos, text_len);
565 			do_munmap(current->mm, realdatastart, data_len + extra);
566 			return result;
567 		}
568 
569 		reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
570 		memp = realdatastart;
571 
572 	} else {
573 
574 		down_write(&current->mm->mmap_sem);
575 		textpos = do_mmap(0, 0, text_len + data_len + extra +
576 					MAX_SHARED_LIBS * sizeof(unsigned long),
577 				PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
578 		up_write(&current->mm->mmap_sem);
579 		if (!textpos  || textpos >= (unsigned long) -4096) {
580 			if (!textpos)
581 				textpos = (unsigned long) -ENOMEM;
582 			printk("Unable to allocate RAM for process text/data, errno %d\n",
583 					(int)-textpos);
584 			return(textpos);
585 		}
586 
587 		realdatastart = textpos + ntohl(hdr->data_start);
588 		datapos = realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long);
589 		reloc = (unsigned long *) (textpos + ntohl(hdr->reloc_start) +
590 				MAX_SHARED_LIBS * sizeof(unsigned long));
591 		memp = textpos;
592 
593 #ifdef CONFIG_BINFMT_ZFLAT
594 		/*
595 		 * load it all in and treat it like a RAM load from now on
596 		 */
597 		if (flags & FLAT_FLAG_GZIP) {
598 			result = decompress_exec(bprm, sizeof (struct flat_hdr),
599 					 (((char *) textpos) + sizeof (struct flat_hdr)),
600 					 (text_len + data_len + (relocs * sizeof(unsigned long))
601 						  - sizeof (struct flat_hdr)),
602 					 0);
603 			memmove((void *) datapos, (void *) realdatastart,
604 					data_len + (relocs * sizeof(unsigned long)));
605 		} else if (flags & FLAT_FLAG_GZDATA) {
606 			fpos = 0;
607 			result = bprm->file->f_op->read(bprm->file,
608 					(char *) textpos, text_len, &fpos);
609 			if (result < (unsigned long) -4096)
610 				result = decompress_exec(bprm, text_len, (char *) datapos,
611 						 data_len + (relocs * sizeof(unsigned long)), 0);
612 		}
613 		else
614 #endif
615 		{
616 			fpos = 0;
617 			result = bprm->file->f_op->read(bprm->file,
618 					(char *) textpos, text_len, &fpos);
619 			if (result < (unsigned long) -4096) {
620 				fpos = ntohl(hdr->data_start);
621 				result = bprm->file->f_op->read(bprm->file, (char *) datapos,
622 					data_len + (relocs * sizeof(unsigned long)), &fpos);
623 			}
624 		}
625 		if (result >= (unsigned long)-4096) {
626 			printk("Unable to read code+data+bss, errno %d\n",(int)-result);
627 			do_munmap(current->mm, textpos, text_len + data_len + extra +
628 				MAX_SHARED_LIBS * sizeof(unsigned long));
629 			return result;
630 		}
631 	}
632 
633 	if (flags & FLAT_FLAG_KTRACE)
634 		printk("Mapping is %x, Entry point is %x, data_start is %x\n",
635 			(int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
636 
637 	/* The main program needs a little extra setup in the task structure */
638 	start_code = textpos + sizeof (struct flat_hdr);
639 	end_code = textpos + text_len;
640 	if (id == 0) {
641 		current->mm->start_code = start_code;
642 		current->mm->end_code = end_code;
643 		current->mm->start_data = datapos;
644 		current->mm->end_data = datapos + data_len;
645 		/*
646 		 * set up the brk stuff, uses any slack left in data/bss/stack
647 		 * allocation.  We put the brk after the bss (between the bss
648 		 * and stack) like other platforms.
649 		 */
650 		current->mm->start_brk = datapos + data_len + bss_len;
651 		current->mm->brk = (current->mm->start_brk + 3) & ~3;
652 		current->mm->context.end_brk = memp + ksize((void *) memp) - stack_len;
653 	}
654 
655 	if (flags & FLAT_FLAG_KTRACE)
656 		printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
657 			id ? "Lib" : "Load", bprm->filename,
658 			(int) start_code, (int) end_code,
659 			(int) datapos,
660 			(int) (datapos + data_len),
661 			(int) (datapos + data_len),
662 			(int) (((datapos + data_len + bss_len) + 3) & ~3));
663 
664 	text_len -= sizeof(struct flat_hdr); /* the real code len */
665 
666 	/* Store the current module values into the global library structure */
667 	libinfo->lib_list[id].start_code = start_code;
668 	libinfo->lib_list[id].start_data = datapos;
669 	libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
670 	libinfo->lib_list[id].text_len = text_len;
671 	libinfo->lib_list[id].loaded = 1;
672 	libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
673 	libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
674 
675 	/*
676 	 * We just load the allocations into some temporary memory to
677 	 * help simplify all this mumbo jumbo
678 	 *
679 	 * We've got two different sections of relocation entries.
680 	 * The first is the GOT which resides at the begining of the data segment
681 	 * and is terminated with a -1.  This one can be relocated in place.
682 	 * The second is the extra relocation entries tacked after the image's
683 	 * data segment. These require a little more processing as the entry is
684 	 * really an offset into the image which contains an offset into the
685 	 * image.
686 	 */
687 	if (flags & FLAT_FLAG_GOTPIC) {
688 		for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
689 			unsigned long addr;
690 			if (*rp) {
691 				addr = calc_reloc(*rp, libinfo, id, 0);
692 				if (addr == RELOC_FAILED)
693 					return -ENOEXEC;
694 				*rp = addr;
695 			}
696 		}
697 	}
698 
699 	/*
700 	 * Now run through the relocation entries.
701 	 * We've got to be careful here as C++ produces relocatable zero
702 	 * entries in the constructor and destructor tables which are then
703 	 * tested for being not zero (which will always occur unless we're
704 	 * based from address zero).  This causes an endless loop as __start
705 	 * is at zero.  The solution used is to not relocate zero addresses.
706 	 * This has the negative side effect of not allowing a global data
707 	 * reference to be statically initialised to _stext (I've moved
708 	 * __start to address 4 so that is okay).
709 	 */
710 	if (rev > OLD_FLAT_VERSION) {
711 		for (i=0; i < relocs; i++) {
712 			unsigned long addr, relval;
713 
714 			/* Get the address of the pointer to be
715 			   relocated (of course, the address has to be
716 			   relocated first).  */
717 			relval = ntohl(reloc[i]);
718 			addr = flat_get_relocate_addr(relval);
719 			rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
720 			if (rp == (unsigned long *)RELOC_FAILED)
721 				return -ENOEXEC;
722 
723 			/* Get the pointer's value.  */
724 			addr = flat_get_addr_from_rp(rp, relval, flags);
725 			if (addr != 0) {
726 				/*
727 				 * Do the relocation.  PIC relocs in the data section are
728 				 * already in target order
729 				 */
730 				if ((flags & FLAT_FLAG_GOTPIC) == 0)
731 					addr = ntohl(addr);
732 				addr = calc_reloc(addr, libinfo, id, 0);
733 				if (addr == RELOC_FAILED)
734 					return -ENOEXEC;
735 
736 				/* Write back the relocated pointer.  */
737 				flat_put_addr_at_rp(rp, addr, relval);
738 			}
739 		}
740 	} else {
741 		for (i=0; i < relocs; i++)
742 			old_reloc(ntohl(reloc[i]));
743 	}
744 
745 	flush_icache_range(start_code, end_code);
746 
747 	/* zero the BSS,  BRK and stack areas */
748 	memset((void*)(datapos + data_len), 0, bss_len +
749 			(memp + ksize((void *) memp) - stack_len -	/* end brk */
750 			libinfo->lib_list[id].start_brk) +		/* start brk */
751 			stack_len);
752 
753 	return 0;
754 }
755 
756 
757 /****************************************************************************/
758 #ifdef CONFIG_BINFMT_SHARED_FLAT
759 
760 /*
761  * Load a shared library into memory.  The library gets its own data
762  * segment (including bss) but not argv/argc/environ.
763  */
764 
765 static int load_flat_shared_library(int id, struct lib_info *libs)
766 {
767 	struct linux_binprm bprm;
768 	int res;
769 	char buf[16];
770 
771 	/* Create the file name */
772 	sprintf(buf, "/lib/lib%d.so", id);
773 
774 	/* Open the file up */
775 	bprm.filename = buf;
776 	bprm.file = open_exec(bprm.filename);
777 	res = PTR_ERR(bprm.file);
778 	if (IS_ERR(bprm.file))
779 		return res;
780 
781 	res = prepare_binprm(&bprm);
782 
783 	if (res <= (unsigned long)-4096)
784 		res = load_flat_file(&bprm, libs, id, NULL);
785 	if (bprm.file) {
786 		allow_write_access(bprm.file);
787 		fput(bprm.file);
788 		bprm.file = NULL;
789 	}
790 	return(res);
791 }
792 
793 #endif /* CONFIG_BINFMT_SHARED_FLAT */
794 /****************************************************************************/
795 
796 /*
797  * These are the functions used to load flat style executables and shared
798  * libraries.  There is no binary dependent code anywhere else.
799  */
800 
801 static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
802 {
803 	struct lib_info libinfo;
804 	unsigned long p = bprm->p;
805 	unsigned long stack_len;
806 	unsigned long start_addr;
807 	unsigned long *sp;
808 	int res;
809 	int i, j;
810 
811 	memset(&libinfo, 0, sizeof(libinfo));
812 	/*
813 	 * We have to add the size of our arguments to our stack size
814 	 * otherwise it's too easy for users to create stack overflows
815 	 * by passing in a huge argument list.  And yes,  we have to be
816 	 * pedantic and include space for the argv/envp array as it may have
817 	 * a lot of entries.
818 	 */
819 #define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
820 	stack_len = TOP_OF_ARGS - bprm->p;             /* the strings */
821 	stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
822 	stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
823 
824 
825 	res = load_flat_file(bprm, &libinfo, 0, &stack_len);
826 	if (res > (unsigned long)-4096)
827 		return res;
828 
829 	/* Update data segment pointers for all libraries */
830 	for (i=0; i<MAX_SHARED_LIBS; i++)
831 		if (libinfo.lib_list[i].loaded)
832 			for (j=0; j<MAX_SHARED_LIBS; j++)
833 				(-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
834 					(libinfo.lib_list[j].loaded)?
835 						libinfo.lib_list[j].start_data:UNLOADED_LIB;
836 
837 	compute_creds(bprm);
838  	current->flags &= ~PF_FORKNOEXEC;
839 
840 	set_binfmt(&flat_format);
841 
842 	p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
843 	DBG_FLT("p=%x\n", (int)p);
844 
845 	/* copy the arg pages onto the stack, this could be more efficient :-) */
846 	for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
847 		* (char *) --p =
848 			((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
849 
850 	sp = (unsigned long *) create_flat_tables(p, bprm);
851 
852 	/* Fake some return addresses to ensure the call chain will
853 	 * initialise library in order for us.  We are required to call
854 	 * lib 1 first, then 2, ... and finally the main program (id 0).
855 	 */
856 	start_addr = libinfo.lib_list[0].entry;
857 
858 #ifdef CONFIG_BINFMT_SHARED_FLAT
859 	for (i = MAX_SHARED_LIBS-1; i>0; i--) {
860 		if (libinfo.lib_list[i].loaded) {
861 			/* Push previos first to call address */
862 			--sp;	put_user(start_addr, sp);
863 			start_addr = libinfo.lib_list[i].entry;
864 		}
865 	}
866 #endif
867 
868 	/* Stash our initial stack pointer into the mm structure */
869 	current->mm->start_stack = (unsigned long )sp;
870 
871 
872 	DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
873 		(int)regs, (int)start_addr, (int)current->mm->start_stack);
874 
875 	start_thread(regs, start_addr, current->mm->start_stack);
876 
877 	if (current->ptrace & PT_PTRACED)
878 		send_sig(SIGTRAP, current, 0);
879 
880 	return 0;
881 }
882 
883 /****************************************************************************/
884 
885 static int __init init_flat_binfmt(void)
886 {
887 	return register_binfmt(&flat_format);
888 }
889 
890 static void __exit exit_flat_binfmt(void)
891 {
892 	unregister_binfmt(&flat_format);
893 }
894 
895 /****************************************************************************/
896 
897 core_initcall(init_flat_binfmt);
898 module_exit(exit_flat_binfmt);
899 
900 /****************************************************************************/
901