1 /****************************************************************************/
3 * linux/fs/binfmt_flat.c
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>
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)
18 #include <linux/module.h>
19 #include <linux/config.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.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>
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>
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>
46 /****************************************************************************/
53 #define DBG_FLT(a...) printk(a)
58 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
59 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */
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];
73 #ifdef CONFIG_BINFMT_SHARED_FLAT
74 static int load_flat_shared_library(int id, struct lib_info *p);
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);
80 static struct linux_binfmt flat_format = {
81 .module = THIS_MODULE,
82 .load_binary = load_flat_binary,
83 .core_dump = flat_core_dump,
84 .min_coredump = PAGE_SIZE
87 /****************************************************************************/
89 * Routine writes a core dump image in the current directory.
90 * Currently only a stub-function.
93 static int flat_core_dump(long signr, struct pt_regs * regs, struct file *file)
95 printk("Process %s:%d received signr %d and should have core dumped\n",
96 current->comm, current->pid, (int) signr);
100 /****************************************************************************/
102 * create_flat_tables() parses the env- and arg-strings in new user
103 * memory and creates the pointer tables from them, and puts their
104 * addresses on the "stack", returning the new stack pointer value.
107 static unsigned long create_flat_tables(
109 struct linux_binprm * bprm)
111 unsigned long *argv,*envp;
113 char * p = (char*)pp;
114 int argc = bprm->argc;
115 int envc = bprm->envc;
118 sp = (unsigned long *) ((-(unsigned long)sizeof(char *))&(unsigned long) p);
125 flat_stack_align(sp);
126 if (flat_argvp_envp_on_stack()) {
127 --sp; put_user((unsigned long) envp, sp);
128 --sp; put_user((unsigned long) argv, sp);
132 current->mm->arg_start = (unsigned long) p;
134 put_user((unsigned long) p, argv++);
136 get_user(dummy, p); p++;
139 put_user((unsigned long) NULL, argv);
140 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
142 put_user((unsigned long)p, envp); envp++;
144 get_user(dummy, p); p++;
147 put_user((unsigned long) NULL, envp);
148 current->mm->env_end = (unsigned long) p;
149 return (unsigned long)sp;
152 /****************************************************************************/
154 #ifdef CONFIG_BINFMT_ZFLAT
156 #include <linux/zlib.h>
158 #define LBUFSIZE 4000
161 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */
162 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
163 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
164 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */
165 #define COMMENT 0x10 /* bit 4 set: file comment present */
166 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
167 #define RESERVED 0xC0 /* bit 6,7: reserved */
169 static int decompress_exec(
170 struct linux_binprm *bprm,
171 unsigned long offset,
181 DBG_FLT("decompress_exec(offset=%x,buf=%x,len=%x)\n",(int)offset, (int)dst, (int)len);
183 memset(&strm, 0, sizeof(strm));
184 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
185 if (strm.workspace == NULL) {
186 DBG_FLT("binfmt_flat: no memory for decompress workspace\n");
189 buf = kmalloc(LBUFSIZE, GFP_KERNEL);
191 DBG_FLT("binfmt_flat: no memory for read buffer\n");
196 /* Read in first chunk of data and parse gzip header. */
198 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
206 /* Check minimum size -- gzip header */
208 DBG_FLT("binfmt_flat: file too small?\n");
212 /* Check gzip magic number */
213 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) {
214 DBG_FLT("binfmt_flat: unknown compression magic?\n");
218 /* Check gzip method */
220 DBG_FLT("binfmt_flat: unknown compression method?\n");
223 /* Check gzip flags */
224 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) ||
225 (buf[3] & RESERVED)) {
226 DBG_FLT("binfmt_flat: unknown flags?\n");
231 if (buf[3] & EXTRA_FIELD) {
232 ret += 2 + buf[10] + (buf[11] << 8);
233 if (unlikely(LBUFSIZE == ret)) {
234 DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n");
238 if (buf[3] & ORIG_NAME) {
239 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
241 if (unlikely(LBUFSIZE == ret)) {
242 DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n");
246 if (buf[3] & COMMENT) {
247 for (; ret < LBUFSIZE && (buf[ret] != 0); ret++)
249 if (unlikely(LBUFSIZE == ret)) {
250 DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n");
256 strm.avail_in -= ret;
259 strm.avail_out = len;
262 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) {
263 DBG_FLT("binfmt_flat: zlib init failed?\n");
267 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) {
268 ret = bprm->file->f_op->read(bprm->file, buf, LBUFSIZE, &fpos);
271 if (ret >= (unsigned long) -4096)
281 DBG_FLT("binfmt_flat: decompression failed (%d), %s\n",
288 zlib_inflateEnd(&strm);
292 kfree(strm.workspace);
297 #endif /* CONFIG_BINFMT_ZFLAT */
299 /****************************************************************************/
302 calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp)
306 unsigned long start_brk;
307 unsigned long start_data;
308 unsigned long text_len;
309 unsigned long start_code;
311 #ifdef CONFIG_BINFMT_SHARED_FLAT
313 id = curid; /* Relocs of 0 are always self referring */
315 id = (r >> 24) & 0xff; /* Find ID for this reloc */
316 r &= 0x00ffffff; /* Trim ID off here */
318 if (id >= MAX_SHARED_LIBS) {
319 printk("BINFMT_FLAT: reference 0x%x to shared library %d",
325 printk("BINFMT_FLAT: reloc address 0x%x not in same module "
326 "(%d != %d)", (unsigned) r, curid, id);
328 } else if ( ! p->lib_list[id].loaded &&
329 load_flat_shared_library(id, p) > (unsigned long) -4096) {
330 printk("BINFMT_FLAT: failed to load library %d", id);
333 /* Check versioning information (i.e. time stamps) */
334 if (p->lib_list[id].build_date && p->lib_list[curid].build_date &&
335 p->lib_list[curid].build_date < p->lib_list[id].build_date) {
336 printk("BINFMT_FLAT: library %d is younger than %d", id, curid);
344 start_brk = p->lib_list[id].start_brk;
345 start_data = p->lib_list[id].start_data;
346 start_code = p->lib_list[id].start_code;
347 text_len = p->lib_list[id].text_len;
349 if (!flat_reloc_valid(r, start_brk - start_data + text_len)) {
350 printk("BINFMT_FLAT: reloc outside program 0x%x (0 - 0x%x/0x%x)",
351 (int) r,(int)(start_brk-start_code),(int)text_len);
355 if (r < text_len) /* In text segment */
356 addr = r + start_code;
357 else /* In data segment */
358 addr = r - text_len + start_data;
360 /* Range checked already above so doing the range tests is redundant...*/
364 printk(", killing %s!\n", current->comm);
365 send_sig(SIGSEGV, current, 0);
370 /****************************************************************************/
372 void old_reloc(unsigned long rl)
375 char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" };
381 #if defined(CONFIG_COLDFIRE)
382 ptr = (unsigned long *) (current->mm->start_code + r.reloc.offset);
384 ptr = (unsigned long *) (current->mm->start_data + r.reloc.offset);
388 printk("Relocation of variable at DATASEG+%x "
389 "(address %p, currently %x) into segment %s\n",
390 r.reloc.offset, ptr, (int)*ptr, segment[r.reloc.type]);
393 switch (r.reloc.type) {
394 case OLD_FLAT_RELOC_TYPE_TEXT:
395 *ptr += current->mm->start_code;
397 case OLD_FLAT_RELOC_TYPE_DATA:
398 *ptr += current->mm->start_data;
400 case OLD_FLAT_RELOC_TYPE_BSS:
401 *ptr += current->mm->end_data;
404 printk("BINFMT_FLAT: Unknown relocation type=%x\n", r.reloc.type);
409 printk("Relocation became %x\n", (int)*ptr);
413 /****************************************************************************/
415 static int load_flat_file(struct linux_binprm * bprm,
416 struct lib_info *libinfo, int id, unsigned long *extra_stack)
418 struct flat_hdr * hdr;
419 unsigned long textpos = 0, datapos = 0, result;
420 unsigned long realdatastart = 0;
421 unsigned long text_len, data_len, bss_len, stack_len, flags;
422 unsigned long memp = 0; /* for finding the brk area */
423 unsigned long extra, rlim;
424 unsigned long *reloc = 0, *rp;
426 int i, rev, relocs = 0;
428 unsigned long start_code, end_code;
430 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */
431 inode = bprm->file->f_dentry->d_inode;
433 text_len = ntohl(hdr->data_start);
434 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start);
435 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end);
436 stack_len = ntohl(hdr->stack_size);
438 stack_len += *extra_stack;
439 *extra_stack = stack_len;
441 relocs = ntohl(hdr->reloc_count);
442 flags = ntohl(hdr->flags);
443 rev = ntohl(hdr->rev);
445 if (strncmp(hdr->magic, "bFLT", 4)) {
447 * because a lot of people do not manage to produce good
448 * flat binaries, we leave this printk to help them realise
449 * the problem. We only print the error if its not a script file
451 if (strncmp(hdr->magic, "#!", 2))
452 printk("BINFMT_FLAT: bad header magic\n");
456 if (flags & FLAT_FLAG_KTRACE)
457 printk("BINFMT_FLAT: Loading file: %s\n", bprm->filename);
459 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) {
460 printk("BINFMT_FLAT: bad flat file version 0x%x (supported 0x%x and 0x%x)\n", rev, FLAT_VERSION, OLD_FLAT_VERSION);
464 /* Don't allow old format executables to use shared libraries */
465 if (rev == OLD_FLAT_VERSION && id != 0) {
466 printk("BINFMT_FLAT: shared libraries are not available before rev 0x%x\n",
472 * fix up the flags for the older format, there were all kinds
473 * of endian hacks, this only works for the simple cases
475 if (rev == OLD_FLAT_VERSION && flat_old_ram_flag(flags))
476 flags = FLAT_FLAG_RAM;
478 #ifndef CONFIG_BINFMT_ZFLAT
479 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) {
480 printk("Support for ZFLAT executables is not enabled.\n");
486 * Check initial limits. This avoids letting people circumvent
487 * size limits imposed on them by creating programs with large
488 * arrays in the data or bss.
490 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
491 if (rlim >= RLIM_INFINITY)
493 if (data_len + bss_len > rlim)
496 /* Flush all traces of the currently running executable */
498 result = flush_old_exec(bprm);
502 /* OK, This is the point of no return */
503 set_personality(PER_LINUX);
507 * calculate the extra space we need to map in
509 extra = max(bss_len + stack_len, relocs * sizeof(unsigned long));
512 * there are a couple of cases here, the separate code/data
513 * case, and then the fully copied to RAM case which lumps
516 if ((flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP)) == 0) {
518 * this should give us a ROM ptr, but if it doesn't we don't
521 DBG_FLT("BINFMT_FLAT: ROM mapping of file (we hope)\n");
523 down_write(¤t->mm->mmap_sem);
524 textpos = do_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, MAP_PRIVATE, 0);
525 up_write(¤t->mm->mmap_sem);
526 if (!textpos || textpos >= (unsigned long) -4096) {
528 textpos = (unsigned long) -ENOMEM;
529 printk("Unable to mmap process text, errno %d\n", (int)-textpos);
533 down_write(¤t->mm->mmap_sem);
534 realdatastart = do_mmap(0, 0, data_len + extra +
535 MAX_SHARED_LIBS * sizeof(unsigned long),
536 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0);
537 up_write(¤t->mm->mmap_sem);
539 if (realdatastart == 0 || realdatastart >= (unsigned long)-4096) {
541 realdatastart = (unsigned long) -ENOMEM;
542 printk("Unable to allocate RAM for process data, errno %d\n",
544 do_munmap(current->mm, textpos, text_len);
545 return realdatastart;
547 datapos = realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long);
549 DBG_FLT("BINFMT_FLAT: Allocated data+bss+stack (%d bytes): %x\n",
550 (int)(data_len + bss_len + stack_len), (int)datapos);
552 fpos = ntohl(hdr->data_start);
553 #ifdef CONFIG_BINFMT_ZFLAT
554 if (flags & FLAT_FLAG_GZDATA) {
555 result = decompress_exec(bprm, fpos, (char *) datapos,
556 data_len + (relocs * sizeof(unsigned long)), 0);
560 result = bprm->file->f_op->read(bprm->file, (char *) datapos,
561 data_len + (relocs * sizeof(unsigned long)), &fpos);
563 if (result >= (unsigned long)-4096) {
564 printk("Unable to read data+bss, errno %d\n", (int)-result);
565 do_munmap(current->mm, textpos, text_len);
566 do_munmap(current->mm, realdatastart, data_len + extra);
570 reloc = (unsigned long *) (datapos+(ntohl(hdr->reloc_start)-text_len));
571 memp = realdatastart;
575 down_write(¤t->mm->mmap_sem);
576 textpos = do_mmap(0, 0, text_len + data_len + extra +
577 MAX_SHARED_LIBS * sizeof(unsigned long),
578 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0);
579 up_write(¤t->mm->mmap_sem);
580 if (!textpos || textpos >= (unsigned long) -4096) {
582 textpos = (unsigned long) -ENOMEM;
583 printk("Unable to allocate RAM for process text/data, errno %d\n",
588 realdatastart = textpos + ntohl(hdr->data_start);
589 datapos = realdatastart + MAX_SHARED_LIBS * sizeof(unsigned long);
590 reloc = (unsigned long *) (textpos + ntohl(hdr->reloc_start) +
591 MAX_SHARED_LIBS * sizeof(unsigned long));
594 #ifdef CONFIG_BINFMT_ZFLAT
596 * load it all in and treat it like a RAM load from now on
598 if (flags & FLAT_FLAG_GZIP) {
599 result = decompress_exec(bprm, sizeof (struct flat_hdr),
600 (((char *) textpos) + sizeof (struct flat_hdr)),
601 (text_len + data_len + (relocs * sizeof(unsigned long))
602 - sizeof (struct flat_hdr)),
604 memmove((void *) datapos, (void *) realdatastart,
605 data_len + (relocs * sizeof(unsigned long)));
606 } else if (flags & FLAT_FLAG_GZDATA) {
608 result = bprm->file->f_op->read(bprm->file,
609 (char *) textpos, text_len, &fpos);
610 if (result < (unsigned long) -4096)
611 result = decompress_exec(bprm, text_len, (char *) datapos,
612 data_len + (relocs * sizeof(unsigned long)), 0);
618 result = bprm->file->f_op->read(bprm->file,
619 (char *) textpos, text_len, &fpos);
620 if (result < (unsigned long) -4096) {
621 fpos = ntohl(hdr->data_start);
622 result = bprm->file->f_op->read(bprm->file, (char *) datapos,
623 data_len + (relocs * sizeof(unsigned long)), &fpos);
626 if (result >= (unsigned long)-4096) {
627 printk("Unable to read code+data+bss, errno %d\n",(int)-result);
628 do_munmap(current->mm, textpos, text_len + data_len + extra +
629 MAX_SHARED_LIBS * sizeof(unsigned long));
634 if (flags & FLAT_FLAG_KTRACE)
635 printk("Mapping is %x, Entry point is %x, data_start is %x\n",
636 (int)textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start));
638 /* The main program needs a little extra setup in the task structure */
639 start_code = textpos + sizeof (struct flat_hdr);
640 end_code = textpos + text_len;
642 current->mm->start_code = start_code;
643 current->mm->end_code = end_code;
644 current->mm->start_data = datapos;
645 current->mm->end_data = datapos + data_len;
647 * set up the brk stuff, uses any slack left in data/bss/stack
648 * allocation. We put the brk after the bss (between the bss
649 * and stack) like other platforms.
651 current->mm->start_brk = datapos + data_len + bss_len;
652 current->mm->brk = (current->mm->start_brk + 3) & ~3;
653 current->mm->context.end_brk = memp + ksize((void *) memp) - stack_len;
656 if (flags & FLAT_FLAG_KTRACE)
657 printk("%s %s: TEXT=%x-%x DATA=%x-%x BSS=%x-%x\n",
658 id ? "Lib" : "Load", bprm->filename,
659 (int) start_code, (int) end_code,
661 (int) (datapos + data_len),
662 (int) (datapos + data_len),
663 (int) (((datapos + data_len + bss_len) + 3) & ~3));
665 text_len -= sizeof(struct flat_hdr); /* the real code len */
667 /* Store the current module values into the global library structure */
668 libinfo->lib_list[id].start_code = start_code;
669 libinfo->lib_list[id].start_data = datapos;
670 libinfo->lib_list[id].start_brk = datapos + data_len + bss_len;
671 libinfo->lib_list[id].text_len = text_len;
672 libinfo->lib_list[id].loaded = 1;
673 libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos;
674 libinfo->lib_list[id].build_date = ntohl(hdr->build_date);
677 * We just load the allocations into some temporary memory to
678 * help simplify all this mumbo jumbo
680 * We've got two different sections of relocation entries.
681 * The first is the GOT which resides at the begining of the data segment
682 * and is terminated with a -1. This one can be relocated in place.
683 * The second is the extra relocation entries tacked after the image's
684 * data segment. These require a little more processing as the entry is
685 * really an offset into the image which contains an offset into the
688 if (flags & FLAT_FLAG_GOTPIC) {
689 for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
692 addr = calc_reloc(*rp, libinfo, id, 0);
693 if (addr == RELOC_FAILED)
701 * Now run through the relocation entries.
702 * We've got to be careful here as C++ produces relocatable zero
703 * entries in the constructor and destructor tables which are then
704 * tested for being not zero (which will always occur unless we're
705 * based from address zero). This causes an endless loop as __start
706 * is at zero. The solution used is to not relocate zero addresses.
707 * This has the negative side effect of not allowing a global data
708 * reference to be statically initialised to _stext (I've moved
709 * __start to address 4 so that is okay).
711 if (rev > OLD_FLAT_VERSION) {
712 for (i=0; i < relocs; i++) {
713 unsigned long addr, relval;
715 /* Get the address of the pointer to be
716 relocated (of course, the address has to be
718 relval = ntohl(reloc[i]);
719 addr = flat_get_relocate_addr(relval);
720 rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
721 if (rp == (unsigned long *)RELOC_FAILED)
724 /* Get the pointer's value. */
725 addr = flat_get_addr_from_rp(rp, relval, flags);
728 * Do the relocation. PIC relocs in the data section are
729 * already in target order
731 if ((flags & FLAT_FLAG_GOTPIC) == 0)
733 addr = calc_reloc(addr, libinfo, id, 0);
734 if (addr == RELOC_FAILED)
737 /* Write back the relocated pointer. */
738 flat_put_addr_at_rp(rp, addr, relval);
742 for (i=0; i < relocs; i++)
743 old_reloc(ntohl(reloc[i]));
746 flush_icache_range(start_code, end_code);
748 /* zero the BSS, BRK and stack areas */
749 memset((void*)(datapos + data_len), 0, bss_len +
750 (memp + ksize((void *) memp) - stack_len - /* end brk */
751 libinfo->lib_list[id].start_brk) + /* start brk */
758 /****************************************************************************/
759 #ifdef CONFIG_BINFMT_SHARED_FLAT
762 * Load a shared library into memory. The library gets its own data
763 * segment (including bss) but not argv/argc/environ.
766 static int load_flat_shared_library(int id, struct lib_info *libs)
768 struct linux_binprm bprm;
772 /* Create the file name */
773 sprintf(buf, "/lib/lib%d.so", id);
775 /* Open the file up */
777 bprm.file = open_exec(bprm.filename);
778 res = PTR_ERR(bprm.file);
779 if (IS_ERR(bprm.file))
782 res = prepare_binprm(&bprm);
784 if (res <= (unsigned long)-4096)
785 res = load_flat_file(&bprm, libs, id, NULL);
787 allow_write_access(bprm.file);
794 #endif /* CONFIG_BINFMT_SHARED_FLAT */
795 /****************************************************************************/
798 * These are the functions used to load flat style executables and shared
799 * libraries. There is no binary dependent code anywhere else.
802 static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
804 struct lib_info libinfo;
805 unsigned long p = bprm->p;
806 unsigned long stack_len;
807 unsigned long start_addr;
812 memset(&libinfo, 0, sizeof(libinfo));
814 * We have to add the size of our arguments to our stack size
815 * otherwise it's too easy for users to create stack overflows
816 * by passing in a huge argument list. And yes, we have to be
817 * pedantic and include space for the argv/envp array as it may have
820 #define TOP_OF_ARGS (PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *))
821 stack_len = TOP_OF_ARGS - bprm->p; /* the strings */
822 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
823 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
826 res = load_flat_file(bprm, &libinfo, 0, &stack_len);
827 if (res > (unsigned long)-4096)
830 /* Update data segment pointers for all libraries */
831 for (i=0; i<MAX_SHARED_LIBS; i++)
832 if (libinfo.lib_list[i].loaded)
833 for (j=0; j<MAX_SHARED_LIBS; j++)
834 (-(j+1))[(unsigned long *)(libinfo.lib_list[i].start_data)] =
835 (libinfo.lib_list[j].loaded)?
836 libinfo.lib_list[j].start_data:UNLOADED_LIB;
839 current->flags &= ~PF_FORKNOEXEC;
841 set_binfmt(&flat_format);
843 p = ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4;
844 DBG_FLT("p=%x\n", (int)p);
846 /* copy the arg pages onto the stack, this could be more efficient :-) */
847 for (i = TOP_OF_ARGS - 1; i >= bprm->p; i--)
849 ((char *) page_address(bprm->page[i/PAGE_SIZE]))[i % PAGE_SIZE];
851 sp = (unsigned long *) create_flat_tables(p, bprm);
853 /* Fake some return addresses to ensure the call chain will
854 * initialise library in order for us. We are required to call
855 * lib 1 first, then 2, ... and finally the main program (id 0).
857 start_addr = libinfo.lib_list[0].entry;
859 #ifdef CONFIG_BINFMT_SHARED_FLAT
860 for (i = MAX_SHARED_LIBS-1; i>0; i--) {
861 if (libinfo.lib_list[i].loaded) {
862 /* Push previos first to call address */
863 --sp; put_user(start_addr, sp);
864 start_addr = libinfo.lib_list[i].entry;
869 /* Stash our initial stack pointer into the mm structure */
870 current->mm->start_stack = (unsigned long )sp;
873 DBG_FLT("start_thread(regs=0x%x, entry=0x%x, start_stack=0x%x)\n",
874 (int)regs, (int)start_addr, (int)current->mm->start_stack);
876 start_thread(regs, start_addr, current->mm->start_stack);
878 if (current->ptrace & PT_PTRACED)
879 send_sig(SIGTRAP, current, 0);
884 /****************************************************************************/
886 static int __init init_flat_binfmt(void)
888 return register_binfmt(&flat_format);
891 static void __exit exit_flat_binfmt(void)
893 unregister_binfmt(&flat_format);
896 /****************************************************************************/
898 core_initcall(init_flat_binfmt);
899 module_exit(exit_flat_binfmt);
901 /****************************************************************************/