fs/binfmt_elf.c

/*
 * linux/fs/binfmt_elf.c
 *
 * These are the functions used to load ELF format executables as used
 * on SVr4 machines.  Information on the format may be found in the book
 * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
 * Tools".
 *
 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
 */

#include <linux/module.h>

#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/a.out.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/compiler.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>

#include <asm/uaccess.h>
#include <asm/param.h>
#include <asm/pgalloc.h>

#include <linux/elf.h>

static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs);
static int load_elf_library(struct file*);
static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int);
extern int dump_fpu (struct pt_regs *, elf_fpregset_t *);

#ifndef elf_addr_t
#define elf_addr_t unsigned long
#endif

/*
 * If we don't support core dumping, then supply a NULL so we
 * don't even try.
 */
#ifdef USE_ELF_CORE_DUMP
static int elf_core_dump(long signr, struct pt_regs * regs, struct file * file);
#else
#define elf_core_dump	NULL
#endif

#if ELF_EXEC_PAGESIZE > PAGE_SIZE
# define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
#else
# define ELF_MIN_ALIGN	PAGE_SIZE
#endif

#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))

static struct linux_binfmt elf_format = {
		.module		= THIS_MODULE,
		.load_binary	= load_elf_binary,
		.load_shlib	= load_elf_library,
		.core_dump	= elf_core_dump,
		.min_coredump	= ELF_EXEC_PAGESIZE
};

#define BAD_ADDR(x)	((unsigned long)(x) > TASK_SIZE)

static void set_brk(unsigned long start, unsigned long end)
{
	start = ELF_PAGEALIGN(start);
	end = ELF_PAGEALIGN(end);
	if (end > start)
		do_brk(start, end - start);
	current->mm->start_brk = current->mm->brk = end;
}


/* We need to explicitly zero any fractional pages
   after the data section (i.e. bss).  This would
   contain the junk from the file that should not
   be in memory */


static void padzero(unsigned long elf_bss)
{
	unsigned long nbyte;

	nbyte = ELF_PAGEOFFSET(elf_bss);
	if (nbyte) {
		nbyte = ELF_MIN_ALIGN - nbyte;
		clear_user((void *) elf_bss, nbyte);
	}
}

/* Let's use some macros to make this stack manipulation a litle clearer */
#ifdef CONFIG_STACK_GROWSUP
#define STACK_ADD(sp, items) ((elf_addr_t *)(sp) + (items))
#define STACK_ROUND(sp, items) \
	((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
#define STACK_ALLOC(sp, len) ({ elf_addr_t *old_sp = sp; sp += len; old_sp; })
#else
#define STACK_ADD(sp, items) ((elf_addr_t *)(sp) - (items))
#define STACK_ROUND(sp, items) \
	(((unsigned long) (sp - items)) &~ 15UL)
#define STACK_ALLOC(sp, len) sp -= len
#endif

static void
create_elf_tables(struct linux_binprm *bprm, struct elfhdr * exec,
		int interp_aout, unsigned long load_addr,
		unsigned long interp_load_addr)
{
	unsigned long p = bprm->p;
	int argc = bprm->argc;
	int envc = bprm->envc;
	elf_addr_t *argv, *envp;
	elf_addr_t *sp, *u_platform;
	const char *k_platform = ELF_PLATFORM;
	int items;
	elf_addr_t elf_info[40];
	int ei_index = 0;

	/*
	 * If this architecture has a platform capability string, copy it
	 * to userspace.  In some cases (Sparc), this info is impossible
	 * for userspace to get any other way, in others (i386) it is
	 * merely difficult.
	 */

	u_platform = NULL;
	if (k_platform) {
		size_t len = strlen(k_platform) + 1;

#ifdef CONFIG_X86_HT
		/*
		 * In some cases (e.g. Hyper-Threading), we want to avoid L1
		 * evictions by the processes running on the same package. One
		 * thing we can do is to shuffle the initial stack for them.
		 *
		 * The conditionals here are unneeded, but kept in to make the
		 * code behaviour the same as pre change unless we have
		 * hyperthreaded processors. This should be cleaned up
		 * before 2.6
		 */
	 
		if (smp_num_siblings > 1)
			STACK_ALLOC(p, ((current->pid % 64) << 7));
#endif
		u_platform = (elf_addr_t *) STACK_ALLOC(p, len);
		__copy_to_user(u_platform, k_platform, len);
	}

	/* Create the ELF interpreter info */
#define NEW_AUX_ENT(id, val) \
	do { elf_info[ei_index++] = id; elf_info[ei_index++] = val; } while (0)

#ifdef ARCH_DLINFO
	/* 
	 * ARCH_DLINFO must come first so PPC can do its special alignment of
	 * AUXV.
	 */
	ARCH_DLINFO;
#endif
	NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
	NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
	NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
	NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
	NEW_AUX_ENT(AT_PHENT, sizeof (struct elf_phdr));
	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
	NEW_AUX_ENT(AT_BASE, interp_load_addr);
	NEW_AUX_ENT(AT_FLAGS, 0);
	NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
	NEW_AUX_ENT(AT_UID, (elf_addr_t) current->uid);
	NEW_AUX_ENT(AT_EUID, (elf_addr_t) current->euid);
	NEW_AUX_ENT(AT_GID, (elf_addr_t) current->gid);
	NEW_AUX_ENT(AT_EGID, (elf_addr_t) current->egid);
	if (k_platform) {
		NEW_AUX_ENT(AT_PLATFORM, (elf_addr_t)(long)u_platform);
	}
	NEW_AUX_ENT(AT_NULL, 0);
#undef NEW_AUX_ENT

	sp = STACK_ADD(p, ei_index);

	items = (argc + 1) + (envc + 1);
	if (interp_aout) {
		items += 3; /* a.out interpreters require argv & envp too */
	} else {
		items += 1; /* ELF interpreters only put argc on the stack */
	}
	bprm->p = STACK_ROUND(sp, items);

	/* Point sp at the lowest address on the stack */
#ifdef CONFIG_STACK_GROWSUP
	sp = (elf_addr_t *)bprm->p - items - ei_index;
	bprm->exec = (unsigned long) sp; /* XXX: PARISC HACK */
#else
	sp = (elf_addr_t *)bprm->p;
#endif

	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
	__put_user(argc, sp++);
	if (interp_aout) {
		argv = sp + 2;
		envp = argv + argc + 1;
		__put_user((elf_addr_t)(long)argv, sp++);
		__put_user((elf_addr_t)(long)envp, sp++);
	} else {
		argv = sp;
		envp = argv + argc + 1;
	}

	/* Populate argv and envp */
	p = current->mm->arg_start;
	while (argc-- > 0) {
		size_t len;
		__put_user((elf_addr_t)p, argv++);
		len = strnlen_user((void *)p, PAGE_SIZE*MAX_ARG_PAGES);
		if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
			return;
		p += len;
	}
	__put_user(NULL, argv);
	current->mm->arg_end = current->mm->env_start = p;
	while (envc-- > 0) {
		size_t len;
		__put_user((elf_addr_t)p, envp++);
		len = strnlen_user((void *)p, PAGE_SIZE*MAX_ARG_PAGES);
		if (!len || len > PAGE_SIZE*MAX_ARG_PAGES)
			return;
		p += len;
	}
	__put_user(NULL, envp);
	current->mm->env_end = p;

	/* Put the elf_info on the stack in the right place.  */
	sp = (elf_addr_t *)envp + 1;
	copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t));
}

#ifndef elf_map

static inline unsigned long
elf_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
{
	unsigned long map_addr;

	down_write(&current->mm->mmap_sem);
	map_addr = do_mmap(filep, ELF_PAGESTART(addr),
			   eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr), prot, type,
			   eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr));
	up_write(&current->mm->mmap_sem);
	return(map_addr);
}

#endif /* !elf_map */

/* This is much more generalized than the library routine read function,
   so we keep this separate.  Technically the library read function
   is only provided so that we can read a.out libraries that have
   an ELF header */

static unsigned long load_elf_interp(struct elfhdr * interp_elf_ex,
				     struct file * interpreter,
				     unsigned long *interp_load_addr)
{
	struct elf_phdr *elf_phdata;
	struct elf_phdr *eppnt;
	unsigned long load_addr = 0;
	int load_addr_set = 0;
	unsigned long last_bss = 0, elf_bss = 0;
	unsigned long error = ~0UL;
	int retval, i, size;

	/* First of all, some simple consistency checks */
	if (interp_elf_ex->e_type != ET_EXEC &&
	    interp_elf_ex->e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(interp_elf_ex))
		goto out;
	if (!interpreter->f_op || !interpreter->f_op->mmap)
		goto out;

	/*
	 * If the size of this structure has changed, then punt, since
	 * we will be doing the wrong thing.
	 */
	if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
		goto out;
	if (interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;

	/* Now read in all of the header information */

	size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
	if (size > ELF_MIN_ALIGN)
		goto out;
	elf_phdata = (struct elf_phdr *) kmalloc(size, GFP_KERNEL);
	if (!elf_phdata)
		goto out;

	retval = kernel_read(interpreter,interp_elf_ex->e_phoff,(char *)elf_phdata,size);
	error = retval;
	if (retval < 0)
		goto out_close;

	eppnt = elf_phdata;
	for (i=0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
	  if (eppnt->p_type == PT_LOAD) {
	    int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
	    int elf_prot = 0;
	    unsigned long vaddr = 0;
	    unsigned long k, map_addr;

	    if (eppnt->p_flags & PF_R) elf_prot =  PROT_READ;
	    if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
	    if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
	    vaddr = eppnt->p_vaddr;
	    if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
	    	elf_type |= MAP_FIXED;

	    map_addr = elf_map(interpreter, load_addr + vaddr, eppnt, elf_prot, elf_type);
	    if (BAD_ADDR(map_addr))
	    	goto out_close;

	    if (!load_addr_set && interp_elf_ex->e_type == ET_DYN) {
		load_addr = map_addr - ELF_PAGESTART(vaddr);
		load_addr_set = 1;
	    }

	    /*
	     * Find the end of the file mapping for this phdr, and keep
	     * track of the largest address we see for this.
	     */
	    k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
	    if (k > elf_bss)
		elf_bss = k;

	    /*
	     * Do the same thing for the memory mapping - between
	     * elf_bss and last_bss is the bss section.
	     */
	    k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
	    if (k > last_bss)
		last_bss = k;
	  }
	}

	/* Now use mmap to map the library into memory. */

	/*
	 * Now fill out the bss section.  First pad the last page up
	 * to the page boundary, and then perform a mmap to make sure
	 * that there are zero-mapped pages up to and including the 
	 * last bss page.
	 */
	padzero(elf_bss);
	elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);	/* What we have mapped so far */

	/* Map the last of the bss segment */
	if (last_bss > elf_bss)
		do_brk(elf_bss, last_bss - elf_bss);

	*interp_load_addr = load_addr;
	error = ((unsigned long) interp_elf_ex->e_entry) + load_addr;

out_close:
	kfree(elf_phdata);
out:
	return error;
}

static unsigned long load_aout_interp(struct exec * interp_ex,
			     struct file * interpreter)
{
	unsigned long text_data, elf_entry = ~0UL;
	char * addr;
	loff_t offset;
	int retval;

	current->mm->end_code = interp_ex->a_text;
	text_data = interp_ex->a_text + interp_ex->a_data;
	current->mm->end_data = text_data;
	current->mm->brk = interp_ex->a_bss + text_data;

	switch (N_MAGIC(*interp_ex)) {
	case OMAGIC:
		offset = 32;
		addr = (char *) 0;
		break;
	case ZMAGIC:
	case QMAGIC:
		offset = N_TXTOFF(*interp_ex);
		addr = (char *) N_TXTADDR(*interp_ex);
		break;
	default:
		goto out;
	}

	do_brk(0, text_data);
	retval = -ENOEXEC;
	if (!interpreter->f_op || !interpreter->f_op->read)
		goto out;
	retval = interpreter->f_op->read(interpreter, addr, text_data, &offset);
	if (retval < 0)
		goto out;
	flush_icache_range((unsigned long)addr,
	                   (unsigned long)addr + text_data);

	do_brk(ELF_PAGESTART(text_data + ELF_MIN_ALIGN - 1),
		interp_ex->a_bss);
	elf_entry = interp_ex->a_entry;

out:
	return elf_entry;
}

/*
 * These are the functions used to load ELF style executables and shared
 * libraries.  There is no binary dependent code anywhere else.
 */

#define INTERPRETER_NONE 0
#define INTERPRETER_AOUT 1
#define INTERPRETER_ELF 2


static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
	struct file *interpreter = NULL; /* to shut gcc up */
 	unsigned long load_addr = 0, load_bias = 0;
	int load_addr_set = 0;
	char * elf_interpreter = NULL;
	unsigned int interpreter_type = INTERPRETER_NONE;
	unsigned char ibcs2_interpreter = 0;
	unsigned long error;
	struct elf_phdr * elf_ppnt, *elf_phdata;
	unsigned long elf_bss, elf_brk;
	int elf_exec_fileno;
	int retval, i;
	unsigned int size;
	unsigned long elf_entry, interp_load_addr = 0;
	unsigned long start_code, end_code, start_data, end_data;
	struct elfhdr elf_ex;
	struct elfhdr interp_elf_ex;
  	struct exec interp_ex;
	char passed_fileno[6];
	
	/* Get the exec-header */
	elf_ex = *((struct elfhdr *) bprm->buf);

	retval = -ENOEXEC;
	/* First of all, some simple consistency checks */
	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	if (elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(&elf_ex))
		goto out;
	if (!bprm->file->f_op||!bprm->file->f_op->mmap)
		goto out;

	/* Now read in all of the header information */

	retval = -ENOMEM;
	if (elf_ex.e_phentsize != sizeof(struct elf_phdr))
		goto out;
	if (elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;
	size = elf_ex.e_phnum * sizeof(struct elf_phdr);
	elf_phdata = (struct elf_phdr *) kmalloc(size, GFP_KERNEL);
	if (!elf_phdata)
		goto out;

	retval = kernel_read(bprm->file, elf_ex.e_phoff, (char *) elf_phdata, size);
	if (retval < 0)
		goto out_free_ph;

	retval = get_unused_fd();
	if (retval < 0)
		goto out_free_ph;
	get_file(bprm->file);
	fd_install(elf_exec_fileno = retval, bprm->file);

	elf_ppnt = elf_phdata;
	elf_bss = 0;
	elf_brk = 0;

	start_code = ~0UL;
	end_code = 0;
	start_data = 0;
	end_data = 0;

	for (i = 0; i < elf_ex.e_phnum; i++) {
		if (elf_ppnt->p_type == PT_INTERP) {
			/* This is the program interpreter used for
			 * shared libraries - for now assume that this
			 * is an a.out format binary
			 */

			retval = -ENOMEM;
			if (elf_ppnt->p_filesz > PATH_MAX)
				goto out_free_file;
			elf_interpreter = (char *) kmalloc(elf_ppnt->p_filesz,
							   GFP_KERNEL);
			if (!elf_interpreter)
				goto out_free_file;

			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
					   elf_interpreter,
					   elf_ppnt->p_filesz);
			if (retval < 0)
				goto out_free_interp;
			/* If the program interpreter is one of these two,
			 * then assume an iBCS2 image. Otherwise assume
			 * a native linux image.
			 */
			if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 ||
			    strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0)
				ibcs2_interpreter = 1;

			SET_PERSONALITY(elf_ex, ibcs2_interpreter);

			interpreter = open_exec(elf_interpreter);
			retval = PTR_ERR(interpreter);
			if (IS_ERR(interpreter))
				goto out_free_interp;
			retval = kernel_read(interpreter, 0, bprm->buf, BINPRM_BUF_SIZE);
			if (retval < 0)
				goto out_free_dentry;

			/* Get the exec headers */
			interp_ex = *((struct exec *) bprm->buf);
			interp_elf_ex = *((struct elfhdr *) bprm->buf);
			break;
		}
		elf_ppnt++;
	}

	/* Some simple consistency checks for the interpreter */
	if (elf_interpreter) {
		interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;

		/* Now figure out which format our binary is */
		if ((N_MAGIC(interp_ex) != OMAGIC) &&
		    (N_MAGIC(interp_ex) != ZMAGIC) &&
		    (N_MAGIC(interp_ex) != QMAGIC))
			interpreter_type = INTERPRETER_ELF;

		if (memcmp(interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
			interpreter_type &= ~INTERPRETER_ELF;

		retval = -ELIBBAD;
		if (!interpreter_type)
			goto out_free_dentry;

		/* Make sure only one type was selected */
		if ((interpreter_type & INTERPRETER_ELF) &&
		     interpreter_type != INTERPRETER_ELF) {
	     		// FIXME - ratelimit this before re-enabling
			// printk(KERN_WARNING "ELF: Ambiguous type, using ELF\n");
			interpreter_type = INTERPRETER_ELF;
		}
	} else {
		/* Executables without an interpreter also need a personality  */
		SET_PERSONALITY(elf_ex, ibcs2_interpreter);
	}

	/* OK, we are done with that, now set up the arg stuff,
	   and then start this sucker up */

	if ((!bprm->sh_bang) && (interpreter_type == INTERPRETER_AOUT)) {
		char *passed_p = passed_fileno;
		sprintf(passed_fileno, "%d", elf_exec_fileno);

		if (elf_interpreter) {
			retval = copy_strings_kernel(1, &passed_p, bprm);
			if (retval)
				goto out_free_dentry; 
			bprm->argc++;
		}
	}

	/* Flush all traces of the currently running executable */
	retval = flush_old_exec(bprm);
	if (retval)
		goto out_free_dentry;

	/* OK, This is the point of no return */
	current->mm->start_data = 0;
	current->mm->end_data = 0;
	current->mm->end_code = 0;
	current->mm->mmap = NULL;
	current->flags &= ~PF_FORKNOEXEC;

	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
	   may depend on the personality.  */
	SET_PERSONALITY(elf_ex, ibcs2_interpreter);

	/* Do this so that we can load the interpreter, if need be.  We will
	   change some of these later */
	current->mm->rss = 0;
	current->mm->free_area_cache = TASK_UNMAPPED_BASE;
	retval = setup_arg_pages(bprm);
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
		return retval;
	}
	
	current->mm->start_stack = bprm->p;

	/* Now we do a little grungy work by mmaping the ELF image into
	   the correct location in memory.  At this point, we assume that
	   the image should be loaded at fixed address, not at a variable
	   address. */

	for(i = 0, elf_ppnt = elf_phdata; i < elf_ex.e_phnum; i++, elf_ppnt++) {
		int elf_prot = 0, elf_flags;
		unsigned long k, vaddr;

		if (elf_ppnt->p_type != PT_LOAD)
			continue;

		if (unlikely (elf_brk > elf_bss)) {
			unsigned long nbyte;
	            
			/* There was a PT_LOAD segment with p_memsz > p_filesz
			   before this one. Map anonymous pages, if needed,
			   and clear the area.  */
			set_brk (elf_bss + load_bias, elf_brk + load_bias);
			nbyte = ELF_PAGEOFFSET(elf_bss);
			if (nbyte) {
				nbyte = ELF_MIN_ALIGN - nbyte;
				if (nbyte > elf_brk - elf_bss)
					nbyte = elf_brk - elf_bss;
				clear_user((void *) elf_bss + load_bias, nbyte);
			}
		}

		if (elf_ppnt->p_flags & PF_R) elf_prot |= PROT_READ;
		if (elf_ppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
		if (elf_ppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;

		elf_flags = MAP_PRIVATE|MAP_DENYWRITE|MAP_EXECUTABLE;

		vaddr = elf_ppnt->p_vaddr;
		if (elf_ex.e_type == ET_EXEC || load_addr_set) {
			elf_flags |= MAP_FIXED;
		} else if (elf_ex.e_type == ET_DYN) {
			/* Try and get dynamic programs out of the way of the default mmap
			   base, as well as whatever program they might try to exec.  This
			   is because the brk will follow the loader, and is not movable.  */
			load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
		}

		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt, elf_prot, elf_flags);
		if (BAD_ADDR(error))
			continue;

		if (!load_addr_set) {
			load_addr_set = 1;
			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
			if (elf_ex.e_type == ET_DYN) {
				load_bias += error -
				             ELF_PAGESTART(load_bias + vaddr);
				load_addr += load_bias;
			}
		}
		k = elf_ppnt->p_vaddr;
		if (k < start_code) start_code = k;
		if (start_data < k) start_data = k;

		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;

		if (k > elf_bss)
			elf_bss = k;
		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
			end_code = k;
		if (end_data < k)
			end_data = k;
		k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
		if (k > elf_brk)
			elf_brk = k;
	}

	elf_ex.e_entry += load_bias;
	elf_bss += load_bias;
	elf_brk += load_bias;
	start_code += load_bias;
	end_code += load_bias;
	start_data += load_bias;
	end_data += load_bias;

	if (elf_interpreter) {
		if (interpreter_type == INTERPRETER_AOUT)
			elf_entry = load_aout_interp(&interp_ex,
						     interpreter);
		else
			elf_entry = load_elf_interp(&interp_elf_ex,
						    interpreter,
						    &interp_load_addr);

		allow_write_access(interpreter);
		fput(interpreter);
		kfree(elf_interpreter);

		if (BAD_ADDR(elf_entry)) {
			printk(KERN_ERR "Unable to load interpreter\n");
			kfree(elf_phdata);
			send_sig(SIGSEGV, current, 0);
			return 0;
		}
	} else {
		elf_entry = elf_ex.e_entry;
	}

	kfree(elf_phdata);

	if (interpreter_type != INTERPRETER_AOUT)
		sys_close(elf_exec_fileno);

	set_binfmt(&elf_format);

	compute_creds(bprm);
	current->flags &= ~PF_FORKNOEXEC;
	create_elf_tables(bprm, &elf_ex, (interpreter_type == INTERPRETER_AOUT),
			load_addr, interp_load_addr);
	/* N.B. passed_fileno might not be initialized? */
	if (interpreter_type == INTERPRETER_AOUT)
		current->mm->arg_start += strlen(passed_fileno) + 1;
	current->mm->end_code = end_code;
	current->mm->start_code = start_code;
	current->mm->start_data = start_data;
	current->mm->end_data = end_data;
	current->mm->start_stack = bprm->p;

	/* Calling set_brk effectively mmaps the pages that we need
	 * for the bss and break sections
	 */
	set_brk(elf_bss, elf_brk);

	padzero(elf_bss);

	if (current->personality & MMAP_PAGE_ZERO) {
		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
		   and some applications "depend" upon this behavior.
		   Since we do not have the power to recompile these, we
		   emulate the SVr4 behavior.  Sigh.  */
		/* N.B. Shouldn't the size here be PAGE_SIZE?? */
		down_write(&current->mm->mmap_sem);
		error = do_mmap(NULL, 0, 4096, PROT_READ | PROT_EXEC,
				MAP_FIXED | MAP_PRIVATE, 0);
		up_write(&current->mm->mmap_sem);
	}

#ifdef ELF_PLAT_INIT
	/*
	 * The ABI may specify that certain registers be set up in special
	 * ways (on i386 %edx is the address of a DT_FINI function, for
	 * example.  This macro performs whatever initialization to
	 * the regs structure is required.
	 */
	ELF_PLAT_INIT(regs);
#endif

	start_thread(regs, elf_entry, bprm->p);
	if (unlikely(current->ptrace & PT_PTRACED)) {
		if (current->ptrace & PT_TRACE_EXEC)
			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
		else
			send_sig(SIGTRAP, current, 0);
	}
	retval = 0;
out:
	return retval;

	/* error cleanup */
out_free_dentry:
	allow_write_access(interpreter);
	fput(interpreter);
out_free_interp:
	if (elf_interpreter)
		kfree(elf_interpreter);
out_free_file:
	sys_close(elf_exec_fileno);
out_free_ph:
	kfree(elf_phdata);
	goto out;
}

/* This is really simpleminded and specialized - we are loading an
   a.out library that is given an ELF header. */

static int load_elf_library(struct file *file)
{
	struct elf_phdr *elf_phdata;
	unsigned long elf_bss, bss, len;
	int retval, error, i, j;
	struct elfhdr elf_ex;

	error = -ENOEXEC;
	retval = kernel_read(file, 0, (char *) &elf_ex, sizeof(elf_ex));
	if (retval != sizeof(elf_ex))
		goto out;

	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	/* First of all, some simple consistency checks */
	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
	   !elf_check_arch(&elf_ex) || !file->f_op || !file->f_op->mmap)
		goto out;

	/* Now read in all of the header information */

	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
	/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */

	error = -ENOMEM;
	elf_phdata = (struct elf_phdr *) kmalloc(j, GFP_KERNEL);
	if (!elf_phdata)
		goto out;

	error = -ENOEXEC;
	retval = kernel_read(file, elf_ex.e_phoff, (char *) elf_phdata, j);
	if (retval != j)
		goto out_free_ph;

	for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
		if ((elf_phdata + i)->p_type == PT_LOAD) j++;
	if (j != 1)
		goto out_free_ph;

	while (elf_phdata->p_type != PT_LOAD) elf_phdata++;

	/* Now use mmap to map the library into memory. */
	down_write(&current->mm->mmap_sem);
	error = do_mmap(file,
			ELF_PAGESTART(elf_phdata->p_vaddr),
			(elf_phdata->p_filesz +
			 ELF_PAGEOFFSET(elf_phdata->p_vaddr)),
			PROT_READ | PROT_WRITE | PROT_EXEC,
			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
			(elf_phdata->p_offset -
			 ELF_PAGEOFFSET(elf_phdata->p_vaddr)));
	up_write(&current->mm->mmap_sem);
	if (error != ELF_PAGESTART(elf_phdata->p_vaddr))
		goto out_free_ph;

	elf_bss = elf_phdata->p_vaddr + elf_phdata->p_filesz;
	padzero(elf_bss);

	len = ELF_PAGESTART(elf_phdata->p_filesz + elf_phdata->p_vaddr + ELF_MIN_ALIGN - 1);
	bss = elf_phdata->p_memsz + elf_phdata->p_vaddr;
	if (bss > len)
		do_brk(len, bss - len);
	error = 0;

out_free_ph:
	kfree(elf_phdata);
out:
	return error;
}

/*
 * Note that some platforms still use traditional core dumps and not
 * the ELF core dump.  Each platform can select it as appropriate.
 */
#ifdef USE_ELF_CORE_DUMP

/*
 * ELF core dumper
 *
 * Modelled on fs/exec.c:aout_core_dump()
 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
 */
/*
 * These are the only things you should do on a core-file: use only these
 * functions to write out all the necessary info.
 */
static int dump_write(struct file *file, const void *addr, int nr)
{
	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
}

static int dump_seek(struct file *file, off_t off)
{
	if (file->f_op->llseek) {
		if (file->f_op->llseek(file, off, 0) != off)
			return 0;
	} else
		file->f_pos = off;
	return 1;
}

/*
 * Decide whether a segment is worth dumping; default is yes to be
 * sure (missing info is worse than too much; etc).
 * Personally I'd include everything, and use the coredump limit...
 *
 * I think we should skip something. But I am not sure how. H.J.
 */
static inline int maydump(struct vm_area_struct *vma)
{
	/*
	 * If we may not read the contents, don't allow us to dump
	 * them either. "dump_write()" can't handle it anyway.
	 */
	if (!(vma->vm_flags & VM_READ))
		return 0;

	/* Do not dump I/O mapped devices! -DaveM */
	if (vma->vm_flags & VM_IO)
		return 0;
#if 1
	if (vma->vm_flags & (VM_WRITE|VM_GROWSUP|VM_GROWSDOWN))
		return 1;
	if (vma->vm_flags & (VM_READ|VM_EXEC|VM_EXECUTABLE|VM_SHARED))
		return 0;
#endif
	return 1;
}

#define roundup(x, y)  ((((x)+((y)-1))/(y))*(y))

/* An ELF note in memory */
struct memelfnote
{
	const char *name;
	int type;
	unsigned int datasz;
	void *data;
};

static int notesize(struct memelfnote *en)
{
	int sz;

	sz = sizeof(struct elf_note);
	sz += roundup(strlen(en->name) + 1, 4);
	sz += roundup(en->datasz, 4);

	return sz;
}

#define DUMP_WRITE(addr, nr)	\
	do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
#define DUMP_SEEK(off)	\
	do { if (!dump_seek(file, (off))) return 0; } while(0)

static int writenote(struct memelfnote *men, struct file *file)
{
	struct elf_note en;

	en.n_namesz = strlen(men->name) + 1;
	en.n_descsz = men->datasz;
	en.n_type = men->type;

	DUMP_WRITE(&en, sizeof(en));
	DUMP_WRITE(men->name, en.n_namesz);
	/* XXX - cast from long long to long to avoid need for libgcc.a */
	DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));	/* XXX */
	DUMP_WRITE(men->data, men->datasz);
	DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));	/* XXX */

	return 1;
}
#undef DUMP_WRITE
#undef DUMP_SEEK

#define DUMP_WRITE(addr, nr)	\
	if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
		goto end_coredump;
#define DUMP_SEEK(off)	\
	if (!dump_seek(file, (off))) \
		goto end_coredump;

static inline void fill_elf_header(struct elfhdr *elf, int segs)
{
	memcpy(elf->e_ident, ELFMAG, SELFMAG);
	elf->e_ident[EI_CLASS] = ELF_CLASS;
	elf->e_ident[EI_DATA] = ELF_DATA;
	elf->e_ident[EI_VERSION] = EV_CURRENT;
	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);

	elf->e_type = ET_CORE;
	elf->e_machine = ELF_ARCH;
	elf->e_version = EV_CURRENT;
	elf->e_entry = 0;
	elf->e_phoff = sizeof(struct elfhdr);
	elf->e_shoff = 0;
	elf->e_flags = 0;
	elf->e_ehsize = sizeof(struct elfhdr);
	elf->e_phentsize = sizeof(struct elf_phdr);
	elf->e_phnum = segs;
	elf->e_shentsize = 0;
	elf->e_shnum = 0;
	elf->e_shstrndx = 0;
	return;
}

static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, off_t offset)
{
	phdr->p_type = PT_NOTE;
	phdr->p_offset = offset;
	phdr->p_vaddr = 0;
	phdr->p_paddr = 0;
	phdr->p_filesz = sz;
	phdr->p_memsz = 0;
	phdr->p_flags = 0;
	phdr->p_align = 0;
	return;
}

static inline void fill_note(struct memelfnote *note, const char *name, int type, 
		unsigned int sz, void *data)
{
	note->name = name;
	note->type = type;
	note->datasz = sz;
	note->data = data;
	return;
}

/*
 * fill up all the fields in prstatus from the given task struct, except registers
 * which need to be filled up seperately.
 */
static inline void fill_prstatus(struct elf_prstatus *prstatus, struct task_struct *p, long signr) 
{
	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
	prstatus->pr_sigpend = p->pending.signal.sig[0];
	prstatus->pr_sighold = p->blocked.sig[0];
	prstatus->pr_pid = p->pid;
	prstatus->pr_ppid = p->parent->pid;
	prstatus->pr_pgrp = p->pgrp;
	prstatus->pr_sid = p->session;
	jiffies_to_timeval(p->utime, &prstatus->pr_utime);
	jiffies_to_timeval(p->stime, &prstatus->pr_stime);
	jiffies_to_timeval(p->cutime, &prstatus->pr_cutime);
	jiffies_to_timeval(p->cstime, &prstatus->pr_cstime);
}

static inline void fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p)
{
	int i, len;
	
	/* first copy the parameters from user space */
	memset(psinfo, 0, sizeof(struct elf_prpsinfo));

	len = p->mm->arg_end - p->mm->arg_start;
	if (len >= ELF_PRARGSZ)
		len = ELF_PRARGSZ-1;
	copy_from_user(&psinfo->pr_psargs,
		      (const char *)p->mm->arg_start, len);
	for(i = 0; i < len; i++)
		if (psinfo->pr_psargs[i] == 0)
			psinfo->pr_psargs[i] = ' ';
	psinfo->pr_psargs[len] = 0;

	psinfo->pr_pid = p->pid;
	psinfo->pr_ppid = p->parent->pid;
	psinfo->pr_pgrp = p->pgrp;
	psinfo->pr_sid = p->session;

	i = p->state ? ffz(~p->state) + 1 : 0;
	psinfo->pr_state = i;
	psinfo->pr_sname = (i < 0 || i > 5) ? '.' : "RSDZTD"[i];
	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
	psinfo->pr_nice = task_nice(p);
	psinfo->pr_flag = p->flags;
	psinfo->pr_uid = NEW_TO_OLD_UID(p->uid);
	psinfo->pr_gid = NEW_TO_OLD_GID(p->gid);
	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
	
	return;
}

/* Here is the structure in which status of each thread is captured. */
struct elf_thread_status
{
	struct list_head list;
	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
	elf_fpregset_t fpu;		/* NT_PRFPREG */
#ifdef ELF_CORE_COPY_XFPREGS
	elf_fpxregset_t xfpu;		/* NT_PRXFPREG */
#endif
	struct memelfnote notes[3];
	int num_notes;
};

/*
 * In order to add the specific thread information for the elf file format,
 * we need to keep a linked list of every threads pr_status and then
 * create a single section for them in the final core file.
 */
static int elf_dump_thread_status(long signr, struct task_struct * p, struct list_head * thread_list)
{

	struct elf_thread_status *t;
	int sz = 0;

	t = kmalloc(sizeof(*t), GFP_ATOMIC);
	if (!t)
		return 0;
	memset(t, 0, sizeof(*t));

	INIT_LIST_HEAD(&t->list);
	t->num_notes = 0;

	fill_prstatus(&t->prstatus, p, signr);
	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);	
	
	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus), &(t->prstatus));
	t->num_notes++;
	sz += notesize(&t->notes[0]);

	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, &t->fpu))) {
		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu), &(t->fpu));
		t->num_notes++;
		sz += notesize(&t->notes[1]);
	}

#ifdef ELF_CORE_COPY_XFPREGS
	if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
		fill_note(&t->notes[2], "LINUX", NT_PRXFPREG, sizeof(t->xfpu), &t->xfpu);
		t->num_notes++;
		sz += notesize(&t->notes[2]);
	}
#endif	
	list_add(&t->list, thread_list);
	return sz;
}

/*
 * Actual dumper
 *
 * This is a two-pass process; first we find the offsets of the bits,
 * and then they are actually written out.  If we run out of core limit
 * we just truncate.
 */
static int elf_core_dump(long signr, struct pt_regs * regs, struct file * file)
{
	int has_dumped = 0;
	mm_segment_t fs;
	int segs;
	size_t size = 0;
	int i;
	struct vm_area_struct *vma;
	struct elfhdr elf;
	off_t offset = 0, dataoff;
	unsigned long limit = current->rlim[RLIMIT_CORE].rlim_cur;
	int numnote = 5;
	struct memelfnote notes[5];
	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
	struct elf_prpsinfo psinfo;	/* NT_PRPSINFO */
 	struct task_struct *g, *p;
 	LIST_HEAD(thread_list);
 	struct list_head *t;
	elf_fpregset_t fpu;
#ifdef ELF_CORE_COPY_XFPREGS
	elf_fpxregset_t xfpu;
#endif
	int thread_status_size = 0;
	
	/* We no longer stop all vm operations
	 * 
	 * This because those proceses that could possibly 
	 * change map_count or the mmap / vma pages are now blocked in do_exit on current finishing
	 * this core dump.
	 *
	 * Only ptrace can touch these memory addresses, but it doesn't change
	 * the map_count or the pages allocated.  So no possibility of crashing exists while dumping
	 * the mm->vm_next areas to the core file.
	 *
	 */
  	
	 /* capture the status of all other threads */
	if (signr) {
		read_lock(&tasklist_lock);
		do_each_thread(g,p)
			if (current->mm == p->mm && current != p) {
				int sz = elf_dump_thread_status(signr, p, &thread_list);
				if (!sz) {
					read_unlock(&tasklist_lock);
					goto cleanup;
				} else
					thread_status_size += sz;
			}
		while_each_thread(g,p);
		read_unlock(&tasklist_lock);
	}

	/* now collect the dump for the current */
	memset(&prstatus, 0, sizeof(prstatus));
	fill_prstatus(&prstatus, current, signr);
	elf_core_copy_regs(&prstatus.pr_reg, regs);
	
	segs = current->mm->map_count;

	/* Set up header */
	fill_elf_header(&elf, segs+1); /* including notes section*/

	has_dumped = 1;
	current->flags |= PF_DUMPCORE;

	/*
	 * Set up the notes in similar form to SVR4 core dumps made
	 * with info from their /proc.
	 */

	fill_note(&notes[0], "CORE", NT_PRSTATUS, sizeof(prstatus), &prstatus);
	
	fill_psinfo(&psinfo, current->group_leader);
	fill_note(&notes[1], "CORE", NT_PRPSINFO, sizeof(psinfo), &psinfo);
	
	fill_note(&notes[2], "CORE", NT_TASKSTRUCT, sizeof(*current), current);
  
  	/* Try to dump the FPU. */
	if ((prstatus.pr_fpvalid = elf_core_copy_task_fpregs(current, &fpu)))
		fill_note(&notes[3], "CORE", NT_PRFPREG, sizeof(fpu), &fpu);
	else
		--numnote;
#ifdef ELF_CORE_COPY_XFPREGS
	if (elf_core_copy_task_xfpregs(current, &xfpu))
		fill_note(&notes[4], "LINUX", NT_PRXFPREG, sizeof(xfpu), &xfpu);
	else
		--numnote;
#else
	numnote --;
#endif	
  
	fs = get_fs();
	set_fs(KERNEL_DS);

	DUMP_WRITE(&elf, sizeof(elf));
	offset += sizeof(elf);				/* Elf header */
	offset += (segs+1) * sizeof(struct elf_phdr);	/* Program headers */

	/* Write notes phdr entry */
	{
		struct elf_phdr phdr;
		int sz = 0;

		for(i = 0; i < numnote; i++)
			sz += notesize(&notes[i]);
		
		sz += thread_status_size;

		fill_elf_note_phdr(&phdr, sz, offset);
		offset += sz;
		DUMP_WRITE(&phdr, sizeof(phdr));
	}

	/* Page-align dumped data */
	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);

	/* Write program headers for segments dump */
	for(vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
		struct elf_phdr phdr;
		size_t sz;

		sz = vma->vm_end - vma->vm_start;

		phdr.p_type = PT_LOAD;
		phdr.p_offset = offset;
		phdr.p_vaddr = vma->vm_start;
		phdr.p_paddr = 0;
		phdr.p_filesz = maydump(vma) ? sz : 0;
		phdr.p_memsz = sz;
		offset += phdr.p_filesz;
		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
		if (vma->vm_flags & VM_WRITE) phdr.p_flags |= PF_W;
		if (vma->vm_flags & VM_EXEC) phdr.p_flags |= PF_X;
		phdr.p_align = ELF_EXEC_PAGESIZE;

		DUMP_WRITE(&phdr, sizeof(phdr));
	}

 	/* write out the notes section */
	for(i = 0; i < numnote; i++)
		if (!writenote(&notes[i], file))
			goto end_coredump;

	/* write out the thread status notes section */
	list_for_each(t, &thread_list) {
		struct elf_thread_status *tmp = list_entry(t, struct elf_thread_status, list);
		for (i = 0; i < tmp->num_notes; i++)
			if (!writenote(&tmp->notes[i], file))
				goto end_coredump;
	}
 
	DUMP_SEEK(dataoff);

	for(vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
		unsigned long addr;

		if (!maydump(vma))
			continue;

		for (addr = vma->vm_start;
		     addr < vma->vm_end;
		     addr += PAGE_SIZE) {
			struct page* page;
			struct vm_area_struct *vma;

			if (get_user_pages(current, current->mm, addr, 1, 0, 1,
						&page, &vma) <= 0) {
				DUMP_SEEK (file->f_pos + PAGE_SIZE);
			} else {
				if (page == ZERO_PAGE(addr)) {
					DUMP_SEEK (file->f_pos + PAGE_SIZE);
				} else {
					void *kaddr;
					flush_cache_page(vma, addr);
					kaddr = kmap(page);
					DUMP_WRITE(kaddr, PAGE_SIZE);
					flush_page_to_ram(page);
					kunmap(page);
				}
				page_cache_release(page);
			}
		}
	}

	if ((off_t) file->f_pos != offset) {
		/* Sanity check */
		printk("elf_core_dump: file->f_pos (%ld) != offset (%ld)\n",
		       (off_t) file->f_pos, offset);
	}

end_coredump:
	set_fs(fs);

cleanup:
	while(!list_empty(&thread_list)) {
		struct list_head *tmp = thread_list.next;
		list_del(tmp);
		kfree(list_entry(tmp, struct elf_thread_status, list));
	}

	return has_dumped;
}

#endif		/* USE_ELF_CORE_DUMP */

static int __init init_elf_binfmt(void)
{
	return register_binfmt(&elf_format);
}

static void __exit exit_elf_binfmt(void)
{
	/* Remove the COFF and ELF loaders. */
	unregister_binfmt(&elf_format);
}

module_init(init_elf_binfmt)
module_exit(exit_elf_binfmt)
MODULE_LICENSE("GPL");