/*
 * 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/sched.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/malloc.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/smp_lock.h>

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

#define DLINFO_ITEMS 13

#include <linux/elf.h>

static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs);
static int load_elf_library(struct file*);
extern int dump_fpu (struct pt_regs *, elf_fpregset_t *);
extern void dump_thread(struct pt_regs *, struct user *);

#ifndef elf_addr_t
#define elf_addr_t unsigned long
#define elf_caddr_t char *
#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

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

static struct linux_binfmt elf_format = {
	NULL, THIS_MODULE, load_elf_binary, load_elf_library, elf_core_dump, ELF_EXEC_PAGESIZE
};

static void set_brk(unsigned long start, unsigned long end)
{
	start = ELF_PAGEALIGN(start);
	end = ELF_PAGEALIGN(end);
	if (end <= start)
		return;
	do_brk(start, end - start);
}


/* 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_EXEC_PAGESIZE - nbyte;
		clear_user((void *) elf_bss, nbyte);
	}
}

static elf_addr_t * 
create_elf_tables(char *p, int argc, int envc,
		  struct elfhdr * exec,
		  unsigned long load_addr,
		  unsigned long load_bias,
		  unsigned long interp_load_addr, int ibcs)
{
	elf_caddr_t *argv;
	elf_caddr_t *envp;
	elf_addr_t *sp, *csp;
	char *k_platform, *u_platform;
	long hwcap;
	size_t platform_len = 0;

	/*
	 * Get hold of platform and hardware capabilities masks for
	 * the machine we are running on.  In some cases (Sparc), 
	 * this info is impossible to get, in others (i386) it is
	 * merely difficult.
	 */

	hwcap = ELF_HWCAP;
	k_platform = ELF_PLATFORM;

	if (k_platform) {
		platform_len = strlen(k_platform) + 1;
		u_platform = p - platform_len;
		__copy_to_user(u_platform, k_platform, platform_len);
	} else
		u_platform = p;

	/*
	 * Force 16 byte _final_ alignment here for generality.
	 * Leave an extra 16 bytes free so that on the PowerPC we
	 * can move the aux table up to start on a 16-byte boundary.
	 */
	sp = (elf_addr_t *)((~15UL & (unsigned long)(u_platform)) - 16UL);
	csp = sp;
	csp -= ((exec ? DLINFO_ITEMS*2 : 4) + (k_platform ? 2 : 0));
	csp -= envc+1;
	csp -= argc+1;
	csp -= (!ibcs ? 3 : 1);	/* argc itself */
	if ((unsigned long)csp & 15UL)
		sp -= ((unsigned long)csp & 15UL) / sizeof(*sp);

	/*
	 * Put the ELF interpreter info on the stack
	 */
#define NEW_AUX_ENT(nr, id, val) \
	  __put_user ((id), sp+(nr*2)); \
	  __put_user ((val), sp+(nr*2+1)); \

	sp -= 2;
	NEW_AUX_ENT(0, AT_NULL, 0);
	if (k_platform) {
		sp -= 2;
		NEW_AUX_ENT(0, AT_PLATFORM, (elf_addr_t)(unsigned long) u_platform);
	}
	sp -= 2;
	NEW_AUX_ENT(0, AT_HWCAP, hwcap);

	if (exec) {
		sp -= 11*2;

		NEW_AUX_ENT(0, AT_PHDR, load_addr + exec->e_phoff);
		NEW_AUX_ENT(1, AT_PHENT, sizeof (struct elf_phdr));
		NEW_AUX_ENT(2, AT_PHNUM, exec->e_phnum);
		NEW_AUX_ENT(3, AT_PAGESZ, ELF_EXEC_PAGESIZE);
		NEW_AUX_ENT(4, AT_BASE, interp_load_addr);
		NEW_AUX_ENT(5, AT_FLAGS, 0);
		NEW_AUX_ENT(6, AT_ENTRY, load_bias + exec->e_entry);
		NEW_AUX_ENT(7, AT_UID, (elf_addr_t) current->uid);
		NEW_AUX_ENT(8, AT_EUID, (elf_addr_t) current->euid);
		NEW_AUX_ENT(9, AT_GID, (elf_addr_t) current->gid);
		NEW_AUX_ENT(10, AT_EGID, (elf_addr_t) current->egid);
	}
#undef NEW_AUX_ENT

	sp -= envc+1;
	envp = (elf_caddr_t *) sp;
	sp -= argc+1;
	argv = (elf_caddr_t *) sp;
	if (!ibcs) {
		__put_user((elf_addr_t)(unsigned long) envp,--sp);
		__put_user((elf_addr_t)(unsigned long) argv,--sp);
	}

	__put_user((elf_addr_t)argc,--sp);
	current->mm->arg_start = (unsigned long) p;
	while (argc-->0) {
		__put_user((elf_caddr_t)(unsigned long)p,argv++);
		p += strlen_user(p);
	}
	__put_user(NULL, argv);
	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
	while (envc-->0) {
		__put_user((elf_caddr_t)(unsigned long)p,envp++);
		p += strlen_user(p);
	}
	__put_user(NULL, envp);
	current->mm->env_end = (unsigned long) p;
	return sp;
}


/* 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->e_machine))
		goto out;
	if (!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;

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

	size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
	if (size > ELF_EXEC_PAGESIZE)
		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 = do_mmap(interpreter,
			    load_addr + ELF_PAGESTART(vaddr),
			    eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr),
			    elf_prot,
			    elf_type,
			    eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr));
	    if (map_addr > -1024UL) /* Real error */
		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_EXEC_PAGESIZE - 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->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_EXEC_PAGESIZE - 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;
	int load_addr_set = 0;
	char * elf_interpreter = NULL;
	unsigned int interpreter_type = INTERPRETER_NONE;
	unsigned char ibcs2_interpreter = 0;
	mm_segment_t old_fs;
	unsigned long error;
	struct elf_phdr * elf_ppnt, *elf_phdata;
	unsigned long elf_bss, k, elf_brk;
	int elf_exec_fileno;
	int retval, size, i;
	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.e_machine))
		goto out;
#if defined(__mips__) && !defined(__mips64)
	/* IRIX5 binaries handled elsewhere.  */
	if (elf_ex.e_flags & EF_MIPS_ARCH) {
		retval = -ENOEXEC;
		goto out;
	}
#endif
#if defined(__mips__) && defined(__mips64)
	/* Linux/MIPS 32-bit binaries handled elsewhere.  */
	if (sizeof(elf_caddr_t) == 8 &&
	    elf_ex.e_ident[EI_CLASS] == ELFCLASS32) {
		retval = -ENOEXEC;
		goto out;
	}
#endif
	if (!bprm->file->f_op||!bprm->file->f_op->mmap)
		goto out;

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

	retval = -ENOMEM;
	size = elf_ex.e_phentsize * elf_ex.e_phnum;
	if (size > 65536)
		goto out;
	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) {
			retval = -EINVAL;
		  	if (elf_interpreter)
				goto out_free_interp;

			/* This is the program interpreter used for
			 * shared libraries - for now assume that this
			 * is an a.out format binary
			 */

			retval = -ENOMEM;
			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;
#if 0
			printk("Using ELF interpreter %s\n", elf_interpreter);
#endif
#ifdef __sparc__
			if (ibcs2_interpreter) {
				unsigned long old_pers = current->personality;
					
				current->personality = PER_SVR4;
				interpreter = open_exec(elf_interpreter);
				current->personality = old_pers;
			} else
#endif
			{
				interpreter = open_exec(elf_interpreter);
			}
			retval = PTR_ERR(interpreter);
			if (IS_ERR(interpreter))
				goto out_free_interp;
			retval = kernel_read(interpreter, 0, bprm->buf, 128);
			if (retval < 0)
				goto out_free_dentry;

			/* Get the exec headers */
			interp_ex = *((struct exec *) bprm->buf);
			interp_elf_ex = *((struct elfhdr *) bprm->buf);
		}
		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) {
			printk(KERN_WARNING "ELF: Ambiguous type, using ELF\n");
			interpreter_type = INTERPRETER_ELF;
		}
	}

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

	if (!bprm->sh_bang) {
		char * passed_p;

		if (interpreter_type == INTERPRETER_AOUT) {
		  sprintf(passed_fileno, "%d", elf_exec_fileno);
		  passed_p = passed_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;
	elf_entry = (unsigned long) elf_ex.e_entry;

	/* 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;
	setup_arg_pages(bprm); /* XXX: check error */
	current->mm->start_stack = bprm->p;

	/* 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_ex.e_type==ET_DYN ? ELF_ET_DYN_BASE : 0);

	/* 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. */

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

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

		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;
		}

		error = do_mmap(bprm->file, ELF_PAGESTART(load_bias + vaddr),
		                (elf_ppnt->p_filesz +
		                ELF_PAGEOFFSET(elf_ppnt->p_vaddr)),
		                elf_prot, elf_flags, (elf_ppnt->p_offset -
		                ELF_PAGEOFFSET(elf_ppnt->p_vaddr)));

		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 += error;
			}
		}
		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;
	}
	set_fs(old_fs);

	elf_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);

		lock_kernel();
		fput(interpreter);
		unlock_kernel();
		kfree(elf_interpreter);

		if (elf_entry == ~0UL) {
			printk(KERN_ERR "Unable to load interpreter\n");
			kfree(elf_phdata);
			send_sig(SIGSEGV, current, 0);
			return 0;
		}
	}

	kfree(elf_phdata);

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

	put_exec_domain(current->exec_domain);
	if (current->binfmt && current->binfmt->module)
		__MOD_DEC_USE_COUNT(current->binfmt->module);
	current->exec_domain = lookup_exec_domain(current->personality);
	current->binfmt = &elf_format;
	if (current->binfmt && current->binfmt->module)
		__MOD_INC_USE_COUNT(current->binfmt->module);

#ifndef VM_STACK_FLAGS
	lock_kernel();
	current->executable = dget(bprm->file->f_dentry);
	unlock_kernel();
#endif
	compute_creds(bprm);
	current->flags &= ~PF_FORKNOEXEC;
	bprm->p = (unsigned long)
	  create_elf_tables((char *)bprm->p,
			bprm->argc,
			bprm->envc,
			(interpreter_type == INTERPRETER_ELF ? &elf_ex : NULL),
			load_addr, load_bias,
			interp_load_addr,
			(interpreter_type == INTERPRETER_AOUT ? 0 : 1));
	/* N.B. passed_fileno might not be initialized? */
	if (interpreter_type == INTERPRETER_AOUT)
		current->mm->arg_start += strlen(passed_fileno) + 1;
	current->mm->start_brk = current->mm->brk = elf_brk;
	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 0
	printk("(start_brk) %lx\n" , (long) current->mm->start_brk);
	printk("(end_code) %lx\n" , (long) current->mm->end_code);
	printk("(start_code) %lx\n" , (long) current->mm->start_code);
	printk("(start_data) %lx\n" , (long) current->mm->start_data);
	printk("(end_data) %lx\n" , (long) current->mm->end_data);
	printk("(start_stack) %lx\n" , (long) current->mm->start_stack);
	printk("(brk) %lx\n" , (long) current->mm->brk);
#endif

	if ( current->personality == PER_SVR4 )
	{
		/* 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?? */
		error = do_mmap(NULL, 0, 4096, PROT_READ | PROT_EXEC,
				MAP_FIXED | MAP_PRIVATE, 0);
	}

#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 (current->flags & PF_PTRACED)
		send_sig(SIGTRAP, current, 0);
	retval = 0;
out:
	return retval;

	/* error cleanup */
out_free_dentry:
	lock_kernel();
	fput(interpreter);
	unlock_kernel();
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 = 0, bss, len, k;
	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.e_machine) || !file->f_op->mmap)
		goto out;

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

	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
	if (j > ELF_EXEC_PAGESIZE)
		goto out;

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

	/* N.B. check for error return?? */
	retval = kernel_read(file, elf_ex.e_phoff, (char *) elf_phdata,
			   sizeof(struct elf_phdr) * elf_ex.e_phnum);

	error = -ENOEXEC;
	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(&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(&current->mm->mmap_sem);
	if (error != ELF_PAGESTART(elf_phdata->p_vaddr))
		goto out_free_ph;

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

	len = ELF_PAGESTART(elf_phdata->p_filesz + elf_phdata->p_vaddr + 
				ELF_EXEC_PAGESIZE - 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 (!(vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC)))
		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), 4);
	sz += roundup(en->datasz, 4);

	return sz;
}

/* #define DEBUG */

#ifdef DEBUG
static void dump_regs(const char *str, elf_greg_t *r)
{
	int i;
	static const char *regs[] = { "ebx", "ecx", "edx", "esi", "edi", "ebp",
					      "eax", "ds", "es", "fs", "gs",
					      "orig_eax", "eip", "cs",
					      "efl", "uesp", "ss"};
	printk("Registers: %s\n", str);

	for(i = 0; i < ELF_NGREG; i++)
	{
		unsigned long val = r[i];
		printk("   %-2d %-5s=%08lx %lu\n", i, regs[i], val, val);
	}
}
#endif

#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);
	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 (!dump_write(file, (addr), (nr))) \
		goto end_coredump;
#define DUMP_SEEK(off)	\
	if (!dump_seek(file, (off))) \
		goto end_coredump;
/*
 * 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;
	int i;
	size_t size;
	struct vm_area_struct *vma;
	struct elfhdr elf;
	off_t offset = 0, dataoff;
	unsigned long limit = current->rlim[RLIMIT_CORE].rlim_cur;
	int numnote = 4;
	struct memelfnote notes[4];
	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
	elf_fpregset_t fpu;		/* NT_PRFPREG */
	struct elf_prpsinfo psinfo;	/* NT_PRPSINFO */

	/* Count what's needed to dump, up to the limit of coredump size */
	segs = 0;
	size = 0;
	for(vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
		if (maydump(vma))
		{
			unsigned long sz = vma->vm_end-vma->vm_start;

			if (size+sz >= limit)
				break;
			else
				size += sz;
		}

		segs++;
	}
#ifdef DEBUG
	printk("elf_core_dump: %d segs taking %d bytes\n", segs, size);
#endif

	/* Set up header */
	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(elf);
	elf.e_shoff = 0;
	elf.e_flags = 0;
	elf.e_ehsize = sizeof(elf);
	elf.e_phentsize = sizeof(struct elf_phdr);
	elf.e_phnum = segs+1;		/* Include notes */
	elf.e_shentsize = 0;
	elf.e_shnum = 0;
	elf.e_shstrndx = 0;

	fs = get_fs();
	set_fs(KERNEL_DS);

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

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

	/*
	 * Set up the notes in similar form to SVR4 core dumps made
	 * with info from their /proc.
	 */
	memset(&psinfo, 0, sizeof(psinfo));
	memset(&prstatus, 0, sizeof(prstatus));

	notes[0].name = "CORE";
	notes[0].type = NT_PRSTATUS;
	notes[0].datasz = sizeof(prstatus);
	notes[0].data = &prstatus;
	prstatus.pr_info.si_signo = prstatus.pr_cursig = signr;
	prstatus.pr_sigpend = current->signal.sig[0];
	prstatus.pr_sighold = current->blocked.sig[0];
	psinfo.pr_pid = prstatus.pr_pid = current->pid;
	psinfo.pr_ppid = prstatus.pr_ppid = current->p_pptr->pid;
	psinfo.pr_pgrp = prstatus.pr_pgrp = current->pgrp;
	psinfo.pr_sid = prstatus.pr_sid = current->session;
	prstatus.pr_utime.tv_sec = CT_TO_SECS(current->times.tms_utime);
	prstatus.pr_utime.tv_usec = CT_TO_USECS(current->times.tms_utime);
	prstatus.pr_stime.tv_sec = CT_TO_SECS(current->times.tms_stime);
	prstatus.pr_stime.tv_usec = CT_TO_USECS(current->times.tms_stime);
	prstatus.pr_cutime.tv_sec = CT_TO_SECS(current->times.tms_cutime);
	prstatus.pr_cutime.tv_usec = CT_TO_USECS(current->times.tms_cutime);
	prstatus.pr_cstime.tv_sec = CT_TO_SECS(current->times.tms_cstime);
	prstatus.pr_cstime.tv_usec = CT_TO_USECS(current->times.tms_cstime);

	/*
	 * This transfers the registers from regs into the standard
	 * coredump arrangement, whatever that is.
	 */
#ifdef ELF_CORE_COPY_REGS
	ELF_CORE_COPY_REGS(prstatus.pr_reg, regs)
#else
	if (sizeof(elf_gregset_t) != sizeof(struct pt_regs))
	{
		printk("sizeof(elf_gregset_t) (%ld) != sizeof(struct pt_regs) (%ld)\n",
			(long)sizeof(elf_gregset_t), (long)sizeof(struct pt_regs));
	}
	else
		*(struct pt_regs *)&prstatus.pr_reg = *regs;
#endif

#ifdef DEBUG
	dump_regs("Passed in regs", (elf_greg_t *)regs);
	dump_regs("prstatus regs", (elf_greg_t *)&prstatus.pr_reg);
#endif

	notes[1].name = "CORE";
	notes[1].type = NT_PRPSINFO;
	notes[1].datasz = sizeof(psinfo);
	notes[1].data = &psinfo;
	i = current->state ? ffz(~current->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 = current->priority-15;
	psinfo.pr_flag = current->flags;
	psinfo.pr_uid = NEW_TO_OLD_UID(current->uid);
	psinfo.pr_gid = NEW_TO_OLD_GID(current->gid);
	{
		int i, len;

		set_fs(fs);

		len = current->mm->arg_end - current->mm->arg_start;
		if (len >= ELF_PRARGSZ)
			len = ELF_PRARGSZ-1;
		copy_from_user(&psinfo.pr_psargs,
			      (const char *)current->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;

		set_fs(KERNEL_DS);
	}
	strncpy(psinfo.pr_fname, current->comm, sizeof(psinfo.pr_fname));

	notes[2].name = "CORE";
	notes[2].type = NT_TASKSTRUCT;
	notes[2].datasz = sizeof(*current);
	notes[2].data = current;

	/* Try to dump the FPU. */
	prstatus.pr_fpvalid = dump_fpu (regs, &fpu);
	if (!prstatus.pr_fpvalid)
	{
		numnote--;
	}
	else
	{
		notes[3].name = "CORE";
		notes[3].type = NT_PRFPREG;
		notes[3].datasz = sizeof(fpu);
		notes[3].data = &fpu;
	}
	
	/* Write notes phdr entry */
	{
		struct elf_phdr phdr;
		int sz = 0;

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

		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;

		offset += phdr.p_filesz;
		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, i = 0;
		i < segs && vma != NULL; vma = vma->vm_next) {
		struct elf_phdr phdr;
		size_t sz;

		i++;

		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));
	}

	for(i = 0; i < numnote; i++)
		if (!writenote(&notes[i], file))
			goto end_coredump;

	set_fs(fs);

	DUMP_SEEK(dataoff);

	for(i = 0, vma = current->mm->mmap;
	    i < segs && vma != NULL;
	    vma = vma->vm_next) {
		unsigned long addr = vma->vm_start;
		unsigned long len = vma->vm_end - vma->vm_start;

		i++;
		if (!maydump(vma))
			continue;
#ifdef DEBUG
		printk("elf_core_dump: writing %08lx %lx\n", addr, len);
#endif
		DUMP_WRITE((void *)addr, len);
	}

	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);
	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)