/*
 * 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).
 */

#ifdef MODULE
#include <linux/module.h>
#include <linux/version.h>
#else
#define MOD_INC_USE_COUNT
#define MOD_DEC_USE_COUNT
#endif

#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/fcntl.h>
#include <linux/ptrace.h>
#include <linux/malloc.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/elfcore.h>

#include <asm/segment.h>
#include <asm/pgtable.h>

#include <linux/config.h>

#include <linux/unistd.h>
typedef int (*sysfun_p)(int);
extern sysfun_p sys_call_table[];
#define SYS(name)	(sys_call_table[__NR_##name])

#define DLINFO_ITEMS 8

#include <linux/elf.h>

static int load_elf_binary(struct linux_binprm * bprm, struct pt_regs * regs);
static int load_elf_library(int fd);
static int elf_core_dump(long signr, struct pt_regs * regs);
extern int dump_fpu (elf_fpregset_t *);

struct linux_binfmt elf_format = {
#ifndef MODULE
	NULL, NULL, load_elf_binary, load_elf_library, elf_core_dump
#else
	NULL, &mod_use_count_, load_elf_binary, load_elf_library, elf_core_dump
#endif
};

/* 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 fpnt, nbyte;
  
	nbyte = elf_bss & (PAGE_SIZE-1);
	if (nbyte) {
		nbyte = PAGE_SIZE - nbyte;
		verify_area(VERIFY_WRITE, (void *) elf_bss, nbyte);
		fpnt = elf_bss;
		do {
			put_fs_byte(0, fpnt++);
		} while (--nbyte);
	}
}

unsigned long * create_elf_tables(char * p,int argc,int envc,struct elfhdr * exec, unsigned int load_addr, int ibcs)
{
	unsigned long *argv,*envp, *dlinfo;
	unsigned long * sp;
	struct vm_area_struct *mpnt;

	mpnt = (struct vm_area_struct *)kmalloc(sizeof(*mpnt), GFP_KERNEL);
	if (mpnt) {
		mpnt->vm_task = current;
		mpnt->vm_start = PAGE_MASK & (unsigned long) p;
		mpnt->vm_end = TASK_SIZE;
		mpnt->vm_page_prot = PAGE_COPY;
#ifdef VM_STACK_FLAGS
		mpnt->vm_flags = VM_STACK_FLAGS;
		mpnt->vm_pte = 0;
#else
#  ifdef VM_GROWSDOWN
		mpnt->vm_flags = VM_GROWSDOWN;
#  endif
#endif
		mpnt->vm_inode = NULL;
		mpnt->vm_offset = 0;
		mpnt->vm_ops = NULL;
		insert_vm_struct(current, mpnt);
#ifndef VM_GROWSDOWN
		current->mm->stk_vma = mpnt;
#endif

	}
	sp = (unsigned long *) (0xfffffffc & (unsigned long) p);
	if(exec) sp -= DLINFO_ITEMS*2;
	dlinfo = sp;
	sp -= envc+1;
	envp = sp;
	sp -= argc+1;
	argv = sp;
	if (!ibcs) {
		put_fs_long((unsigned long)envp,--sp);
		put_fs_long((unsigned long)argv,--sp);
	}

	/* The constant numbers (0-9) that we are writing here are
	   described in the header file sys/auxv.h on at least
	   some versions of SVr4 */
	if(exec) { /* Put this here for an ELF program interpreter */
	  struct elf_phdr * eppnt;
	  eppnt = (struct elf_phdr *) exec->e_phoff;
	  put_fs_long(3,dlinfo++); put_fs_long(load_addr + exec->e_phoff,dlinfo++);
	  put_fs_long(4,dlinfo++); put_fs_long(sizeof(struct elf_phdr),dlinfo++);
	  put_fs_long(5,dlinfo++); put_fs_long(exec->e_phnum,dlinfo++);
	  put_fs_long(9,dlinfo++); put_fs_long((unsigned long) exec->e_entry,dlinfo++);
	  put_fs_long(7,dlinfo++); put_fs_long(SHM_RANGE_START,dlinfo++);
	  put_fs_long(8,dlinfo++); put_fs_long(0,dlinfo++);
	  put_fs_long(6,dlinfo++); put_fs_long(PAGE_SIZE,dlinfo++);
	  put_fs_long(0,dlinfo++); put_fs_long(0,dlinfo++);
	};

	put_fs_long((unsigned long)argc,--sp);
	current->mm->arg_start = (unsigned long) p;
	while (argc-->0) {
		put_fs_long((unsigned long) p,argv++);
		while (get_fs_byte(p++)) /* nothing */ ;
	}
	put_fs_long(0,argv);
	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
	while (envc-->0) {
		put_fs_long((unsigned long) p,envp++);
		while (get_fs_byte(p++)) /* nothing */ ;
	}
	put_fs_long(0,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 int load_elf_interp(struct elfhdr * interp_elf_ex,
			     struct inode * interpreter_inode)
{
        struct file * file;
	struct elf_phdr *elf_phdata  =  NULL;
	struct elf_phdr *eppnt;
	unsigned int len;
	unsigned int load_addr;
	int elf_exec_fileno;
	int elf_bss;
	int old_fs, retval;
	unsigned int last_bss;
	int error;
	int i, k;
	
	elf_bss = 0;
	last_bss = 0;
	error = load_addr = 0;
	
	/* First of all, some simple consistency checks */
	if((interp_elf_ex->e_type != ET_EXEC && 
	    interp_elf_ex->e_type != ET_DYN) || 
	   (interp_elf_ex->e_machine != EM_386 && interp_elf_ex->e_machine != EM_486) ||
	   (!interpreter_inode->i_op ||
	    !interpreter_inode->i_op->default_file_ops->mmap)){
		return 0xffffffff;
	};
	
	/* Now read in all of the header information */
	
	if(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum > PAGE_SIZE) 
	    return 0xffffffff;
	
	elf_phdata =  (struct elf_phdr *) 
		kmalloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum, GFP_KERNEL);
	if(!elf_phdata) return 0xffffffff;
	
	old_fs = get_fs();
	set_fs(get_ds());
	retval = read_exec(interpreter_inode, interp_elf_ex->e_phoff, (char *) elf_phdata,
			   sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);
	set_fs(old_fs);
	
	elf_exec_fileno = open_inode(interpreter_inode, O_RDONLY);
	if (elf_exec_fileno < 0) return 0xffffffff;
	file = current->files->fd[elf_exec_fileno];

	eppnt = elf_phdata;
	for(i=0; i<interp_elf_ex->e_phnum; i++, eppnt++)
	  if(eppnt->p_type == PT_LOAD) {
	    int elf_prot = (eppnt->p_flags & PF_R) ? PROT_READ : 0;
	    if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
	    if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
	    error = do_mmap(file, 
			    eppnt->p_vaddr & 0xfffff000,
			    eppnt->p_filesz + (eppnt->p_vaddr & 0xfff),
			    elf_prot,
			    MAP_PRIVATE | MAP_DENYWRITE | (interp_elf_ex->e_type == ET_EXEC ? MAP_FIXED : 0),
			    eppnt->p_offset & 0xfffff000);
	    
	    if(!load_addr && interp_elf_ex->e_type == ET_DYN)
	      load_addr = error;
	    k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
	    if(k > elf_bss) elf_bss = k;
	    if(error < 0 && error > -1024) break;  /* Real error */
	    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. */

	
	SYS(close)(elf_exec_fileno);
	if(error < 0 && error > -1024) {
	        kfree(elf_phdata);
		return 0xffffffff;
	}

	padzero(elf_bss);
	len = (elf_bss + 0xfff) & 0xfffff000; /* What we have mapped so far */

	/* Map the last of the bss segment */
	if (last_bss > len)
	  do_mmap(NULL, len, last_bss-len,
		  PROT_READ|PROT_WRITE|PROT_EXEC,
		  MAP_FIXED|MAP_PRIVATE, 0);
	kfree(elf_phdata);

	return ((unsigned int) interp_elf_ex->e_entry) + load_addr;
}

static unsigned int load_aout_interp(struct exec * interp_ex,
			     struct inode * interpreter_inode)
{
  int retval;
  unsigned int elf_entry;
  
  current->mm->brk = interp_ex->a_bss +
    (current->mm->end_data = interp_ex->a_data +
     (current->mm->end_code = interp_ex->a_text));
  elf_entry = interp_ex->a_entry;
  
  
  if (N_MAGIC(*interp_ex) == OMAGIC) {
    do_mmap(NULL, 0, interp_ex->a_text+interp_ex->a_data,
	    PROT_READ|PROT_WRITE|PROT_EXEC,
	    MAP_FIXED|MAP_PRIVATE, 0);
    retval = read_exec(interpreter_inode, 32, (char *) 0, 
		       interp_ex->a_text+interp_ex->a_data);
  } else if (N_MAGIC(*interp_ex) == ZMAGIC || N_MAGIC(*interp_ex) == QMAGIC) {
    do_mmap(NULL, 0, interp_ex->a_text+interp_ex->a_data,
	    PROT_READ|PROT_WRITE|PROT_EXEC,
	    MAP_FIXED|MAP_PRIVATE, 0);
    retval = read_exec(interpreter_inode,
		       N_TXTOFF(*interp_ex) ,
		       (char *) N_TXTADDR(*interp_ex),
		       interp_ex->a_text+interp_ex->a_data);
  } else
    retval = -1;
  
  if(retval >= 0)
    do_mmap(NULL, (interp_ex->a_text + interp_ex->a_data + 0xfff) & 
	    0xfffff000, interp_ex->a_bss,
	    PROT_READ|PROT_WRITE|PROT_EXEC,
	    MAP_FIXED|MAP_PRIVATE, 0);
  if(retval < 0) return 0xffffffff;
  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 elfhdr elf_ex;
	struct elfhdr interp_elf_ex;
	struct file * file;
  	struct exec interp_ex;
	struct inode *interpreter_inode;
	unsigned int load_addr;
	unsigned int interpreter_type = INTERPRETER_NONE;
	unsigned char ibcs2_interpreter;
	int i;
	int old_fs;
	int error;
	struct elf_phdr * elf_ppnt, *elf_phdata;
	int elf_exec_fileno;
	unsigned int elf_bss, k, elf_brk;
	int retval;
	char * elf_interpreter;
	unsigned int elf_entry;
	int status;
	unsigned int start_code, end_code, end_data;
	unsigned int elf_stack;
	char passed_fileno[6];
	
	MOD_INC_USE_COUNT;

	ibcs2_interpreter = 0;
	status = 0;
	load_addr = 0;
	elf_ex = *((struct elfhdr *) bprm->buf);	  /* exec-header */
	
	if (elf_ex.e_ident[0] != 0x7f ||
	    strncmp(&elf_ex.e_ident[1], "ELF",3) != 0) {
		MOD_DEC_USE_COUNT;
		return  -ENOEXEC;
	}
	
	
	/* First of all, some simple consistency checks */
	if(elf_ex.e_type != ET_EXEC || 
	   (elf_ex.e_machine != EM_386 && elf_ex.e_machine != EM_486) ||
	   (!bprm->inode->i_op || !bprm->inode->i_op->default_file_ops ||
	    !bprm->inode->i_op->default_file_ops->mmap)){
		MOD_DEC_USE_COUNT;
		return -ENOEXEC;
	};
	
	/* Now read in all of the header information */
	
	elf_phdata = (struct elf_phdr *) kmalloc(elf_ex.e_phentsize * 
						 elf_ex.e_phnum, GFP_KERNEL);
	
	old_fs = get_fs();
	set_fs(get_ds());
	retval = read_exec(bprm->inode, elf_ex.e_phoff, (char *) elf_phdata,
			   elf_ex.e_phentsize * elf_ex.e_phnum);
	set_fs(old_fs);
	if (retval < 0) {
	        kfree (elf_phdata);
		MOD_DEC_USE_COUNT;
		return retval;
	}
	
	elf_ppnt = elf_phdata;
	
	elf_bss = 0;
	elf_brk = 0;
	
	elf_exec_fileno = open_inode(bprm->inode, O_RDONLY);

	if (elf_exec_fileno < 0) {
	        kfree (elf_phdata);
		MOD_DEC_USE_COUNT;
		return elf_exec_fileno;
	}
	
	file = current->files->fd[elf_exec_fileno];
	
	elf_stack = 0xffffffff;
	elf_interpreter = NULL;
	start_code = 0;
	end_code = 0;
	end_data = 0;
	
	old_fs = get_fs();
	set_fs(get_ds());
	
	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 */
			
			elf_interpreter = (char *) kmalloc(elf_ppnt->p_filesz, 
							   GFP_KERNEL);
			
			retval = read_exec(bprm->inode,elf_ppnt->p_offset,elf_interpreter,
					   elf_ppnt->p_filesz);
			/* 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
			if(retval >= 0)
				retval = namei(elf_interpreter, &interpreter_inode);
			if(retval >= 0)
				retval = read_exec(interpreter_inode,0,bprm->buf,128);
			
			if(retval >= 0){
				interp_ex = *((struct exec *) bprm->buf);		/* exec-header */
				interp_elf_ex = *((struct elfhdr *) bprm->buf);	  /* exec-header */
				
			};
			if(retval < 0) {
			  kfree (elf_phdata);
			  kfree(elf_interpreter);
			  MOD_DEC_USE_COUNT;
			  return retval;
			};
		};
		elf_ppnt++;
	};
	
	set_fs(old_fs);
	
	/* Some simple consistency checks for the interpreter */
	if(elf_interpreter){
	        interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;
		if(retval < 0) {
			kfree(elf_interpreter);
			kfree(elf_phdata);
			MOD_DEC_USE_COUNT;
			return -ELIBACC;
		};
		/* 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 (interp_elf_ex.e_ident[0] != 0x7f ||
		    strncmp(&interp_elf_ex.e_ident[1], "ELF",3) != 0)
		  interpreter_type &= ~INTERPRETER_ELF;

		if(!interpreter_type)
		  {
		    kfree(elf_interpreter);
		    kfree(elf_phdata);
		    MOD_DEC_USE_COUNT;
		    return -ELIBBAD;
		  };
	}
	
	/* 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) {
		    bprm->p = copy_strings(1,&passed_p,bprm->page,bprm->p,2);
		    bprm->argc++;
		  };
		};
		if (!bprm->p) {
		        if(elf_interpreter) {
			      kfree(elf_interpreter);
			}
		        kfree (elf_phdata);
			MOD_DEC_USE_COUNT;
			return -E2BIG;
		}
	}
	
	/* OK, This is the point of no return */
	flush_old_exec(bprm);

	current->mm->end_data = 0;
	current->mm->end_code = 0;
	current->mm->start_mmap = ELF_START_MMAP;
	current->mm->mmap = NULL;
	elf_entry = (unsigned int) elf_ex.e_entry;
	
	/* Do this so that we can load the interpreter, if need be.  We will
	   change some of these later */
	current->mm->rss = 0;
	bprm->p += setup_arg_pages(0, bprm->page);
	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. */
	
	old_fs = get_fs();
	set_fs(get_ds());
	
	elf_ppnt = elf_phdata;
	for(i=0;i < elf_ex.e_phnum; i++){
		
		if(elf_ppnt->p_type == PT_INTERP) {
			/* Set these up so that we are able to load the interpreter */
		  /* Now load the interpreter into user address space */
		  set_fs(old_fs);

		  if(interpreter_type & 1) elf_entry = 
		    load_aout_interp(&interp_ex, interpreter_inode);

		  if(interpreter_type & 2) elf_entry = 
		    load_elf_interp(&interp_elf_ex, interpreter_inode);

		  old_fs = get_fs();
		  set_fs(get_ds());

		  iput(interpreter_inode);
		  kfree(elf_interpreter);
			
		  if(elf_entry == 0xffffffff) { 
		    printk("Unable to load interpreter\n");
		    kfree(elf_phdata);
		    send_sig(SIGSEGV, current, 0);
		    MOD_DEC_USE_COUNT;
		    return 0;
		  };
		};
		
		
		if(elf_ppnt->p_type == PT_LOAD) {
			int elf_prot = (elf_ppnt->p_flags & PF_R) ? PROT_READ : 0;
			if (elf_ppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
			if (elf_ppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
			error = do_mmap(file,
					elf_ppnt->p_vaddr & 0xfffff000,
					elf_ppnt->p_filesz + (elf_ppnt->p_vaddr & 0xfff),
					elf_prot,
					MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
					elf_ppnt->p_offset & 0xfffff000);
			
#ifdef LOW_ELF_STACK
			if(elf_ppnt->p_vaddr & 0xfffff000 < elf_stack) 
				elf_stack = elf_ppnt->p_vaddr & 0xfffff000;
#endif
			
			if(!load_addr) 
			  load_addr = elf_ppnt->p_vaddr - elf_ppnt->p_offset;
			k = elf_ppnt->p_vaddr;
			if(k > start_code) start_code = k;
			k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
			if(k > elf_bss) elf_bss = k;
			if((elf_ppnt->p_flags | PROT_WRITE) && 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_ppnt++;
	};
	set_fs(old_fs);
	
	kfree(elf_phdata);
	
	if(interpreter_type != INTERPRETER_AOUT) SYS(close)(elf_exec_fileno);
	current->personality = (ibcs2_interpreter ? PER_SVR4 : PER_LINUX);

	if (current->exec_domain && current->exec_domain->use_count)
		(*current->exec_domain->use_count)--;
	if (current->binfmt && current->binfmt->use_count)
		(*current->binfmt->use_count)--;
	current->exec_domain = lookup_exec_domain(current->personality);
	current->binfmt = &elf_format;
	if (current->exec_domain && current->exec_domain->use_count)
		(*current->exec_domain->use_count)++;
	if (current->binfmt && current->binfmt->use_count)
		(*current->binfmt->use_count)++;

#ifndef VM_STACK_FLAGS
	current->executable = bprm->inode;
	bprm->inode->i_count++;
#endif
#ifdef LOW_ELF_STACK
	current->start_stack = p = elf_stack - 4;
#endif
	bprm->p -= MAX_ARG_PAGES*PAGE_SIZE;
	bprm->p = (unsigned long) 
	  create_elf_tables((char *)bprm->p,
			bprm->argc,
			bprm->envc,
			(interpreter_type == INTERPRETER_ELF ? &elf_ex : NULL),
			load_addr,    
			(interpreter_type == INTERPRETER_AOUT ? 0 : 1));
	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->end_data = end_data;
	current->mm->start_stack = bprm->p;
	current->suid = current->euid = current->fsuid = bprm->e_uid;
	current->sgid = current->egid = current->fsgid = bprm->e_gid;

	/* Calling sys_brk effectively mmaps the pages that we need for the bss and break
	   sections */
	current->mm->brk = (elf_bss + 0xfff) & 0xfffff000;
	SYS(brk)((elf_brk + 0xfff) & 0xfffff000);

	padzero(elf_bss);

#if 0
	printk("(start_brk) %x\n" , current->mm->start_brk);
	printk("(end_code) %x\n" , current->mm->end_code);
	printk("(start_code) %x\n" , current->mm->start_code);
	printk("(end_data) %x\n" , current->mm->end_data);
	printk("(start_stack) %x\n" , current->mm->start_stack);
	printk("(brk) %x\n" , 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.  */
		error = do_mmap(NULL, 0, 4096, PROT_READ | PROT_EXEC,
				MAP_FIXED | MAP_PRIVATE, 0);
	}

	start_thread(regs, elf_entry, bprm->p);
	if (current->flags & PF_PTRACED)
		send_sig(SIGTRAP, current, 0);
	MOD_DEC_USE_COUNT;
	return 0;
}

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

static int
load_elf_library(int fd){
        struct file * file;
	struct elfhdr elf_ex;
	struct elf_phdr *elf_phdata  =  NULL;
	struct  inode * inode;
	unsigned int len;
	int elf_bss;
	int old_fs, retval;
	unsigned int bss;
	int error;
	int i,j, k;

	MOD_INC_USE_COUNT;
	len = 0;
	file = current->files->fd[fd];
	inode = file->f_inode;
	elf_bss = 0;
	
	set_fs(KERNEL_DS);
	if (file->f_op->read(inode, file, (char *) &elf_ex, sizeof(elf_ex)) != sizeof(elf_ex)) {
		SYS(close)(fd);
		MOD_DEC_USE_COUNT;
		return -EACCES;
	}
	set_fs(USER_DS);
	
	if (elf_ex.e_ident[0] != 0x7f ||
	    strncmp(&elf_ex.e_ident[1], "ELF",3) != 0) {
		MOD_DEC_USE_COUNT;
		return -ENOEXEC;
	}
	
	/* First of all, some simple consistency checks */
	if(elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
	   (elf_ex.e_machine != EM_386 && elf_ex.e_machine != EM_486) ||
	   (!inode->i_op || !inode->i_op->default_file_ops->mmap)){
		MOD_DEC_USE_COUNT;
		return -ENOEXEC;
	};
	
	/* Now read in all of the header information */
	
	if(sizeof(struct elf_phdr) * elf_ex.e_phnum > PAGE_SIZE) {
		MOD_DEC_USE_COUNT;
		return -ENOEXEC;
	}
	
	elf_phdata =  (struct elf_phdr *) 
		kmalloc(sizeof(struct elf_phdr) * elf_ex.e_phnum, GFP_KERNEL);
	
	old_fs = get_fs();
	set_fs(get_ds());
	retval = read_exec(inode, elf_ex.e_phoff, (char *) elf_phdata,
			   sizeof(struct elf_phdr) * elf_ex.e_phnum);
	set_fs(old_fs);
	
	j = 0;
	for(i=0; i<elf_ex.e_phnum; i++)
		if((elf_phdata + i)->p_type == PT_LOAD) j++;
	
	if(j != 1)  {
		kfree(elf_phdata);
		MOD_DEC_USE_COUNT;
		return -ENOEXEC;
	};
	
	while(elf_phdata->p_type != PT_LOAD) elf_phdata++;
	
	/* Now use mmap to map the library into memory. */
	error = do_mmap(file,
			elf_phdata->p_vaddr & 0xfffff000,
			elf_phdata->p_filesz + (elf_phdata->p_vaddr & 0xfff),
			PROT_READ | PROT_WRITE | PROT_EXEC,
			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
			elf_phdata->p_offset & 0xfffff000);

	k = elf_phdata->p_vaddr + elf_phdata->p_filesz;
	if(k > elf_bss) elf_bss = k;
	
	SYS(close)(fd);
	if (error != elf_phdata->p_vaddr & 0xfffff000) {
	        kfree(elf_phdata);
		MOD_DEC_USE_COUNT;
		return error;
	}

	padzero(elf_bss);

	len = (elf_phdata->p_filesz + elf_phdata->p_vaddr+ 0xfff) & 0xfffff000;
	bss = elf_phdata->p_memsz + elf_phdata->p_vaddr;
	if (bss > len)
	  do_mmap(NULL, len, bss-len,
		  PROT_READ|PROT_WRITE|PROT_EXEC,
		  MAP_FIXED|MAP_PRIVATE, 0);
	kfree(elf_phdata);
	MOD_DEC_USE_COUNT;
	return 0;
}

/*
 * 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, void *addr, int nr)
{
	return file->f_op->write(file->f_inode, file, addr, nr) == nr;
}

static int dump_seek(struct file *file, off_t off)
{
	if (file->f_op->lseek) {
		if (file->f_op->lseek(file->f_inode, 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 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
{
	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 close_coredump;
#define DUMP_SEEK(off)	\
	if (!dump_seek(&file, (off))) \
		goto close_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)
{
	int has_dumped = 0;
	struct file file;
	struct inode *inode;
	unsigned short fs;
	char corefile[6+sizeof(current->comm)];
	int segs;
	int i;
	size_t size;
	struct vm_area_struct *vma;
	struct elfhdr elf;
	off_t offset = 0, dataoff;
	int 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 */
	
	if (!current->dumpable || limit < PAGE_SIZE)
		return 0;
	current->dumpable = 0;

#ifndef CONFIG_BINFMT_ELF
	MOD_INC_USE_COUNT;
#endif

	/* 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) {
		int sz = vma->vm_end-vma->vm_start;
		
		if (!maydump(vma))
			continue;

		if (size+sz > limit)
			break;
		
		segs++;
		size += sz;
	}
#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] = ELFCLASS32;
	elf.e_ident[EI_DATA] = ELFDATA2LSB;
	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 = EM_386;
	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);
	memcpy(corefile,"core.",5);
#if 0
	memcpy(corefile+5,current->comm,sizeof(current->comm));
#else
	corefile[4] = '\0';
#endif
	if (open_namei(corefile,O_CREAT | 2 | O_TRUNC,0600,&inode,NULL)) {
		inode = NULL;
		goto end_coredump;
	}
	if (!S_ISREG(inode->i_mode))
		goto end_coredump;
	if (!inode->i_op || !inode->i_op->default_file_ops)
		goto end_coredump;
	file.f_mode = 3;
	file.f_flags = 0;
	file.f_count = 1;
	file.f_inode = inode;
	file.f_pos = 0;
	file.f_reada = 0;
	file.f_op = inode->i_op->default_file_ops;
	if (file.f_op->open)
		if (file.f_op->open(inode,&file))
			goto end_coredump;
	if (!file.f_op->write)
		goto close_coredump;
	has_dumped = 1;

	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;
	prstatus.pr_sighold = current->blocked;
	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->utime);
	prstatus.pr_utime.tv_usec = CT_TO_USECS(current->utime);
	prstatus.pr_stime.tv_sec = CT_TO_SECS(current->stime);
	prstatus.pr_stime.tv_usec = CT_TO_USECS(current->stime);
	prstatus.pr_cutime.tv_sec = CT_TO_SECS(current->cutime);
	prstatus.pr_cutime.tv_usec = CT_TO_USECS(current->cutime);
	prstatus.pr_cstime.tv_sec = CT_TO_SECS(current->cstime);
	prstatus.pr_cstime.tv_usec = CT_TO_USECS(current->cstime);
	if (sizeof(elf_gregset_t) != sizeof(struct pt_regs))
	{
		printk("sizeof(elf_gregset_t) (%d) != sizeof(struct pt_regs) (%d)\n",
			sizeof(elf_gregset_t), sizeof(struct pt_regs));
	}
	else
		*(struct pt_regs *)&prstatus.pr_reg = *regs;
	
#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;
	psinfo.pr_state = current->state;
	psinfo.pr_sname = (current->state < 0 || current->state > 5) ? '.' : "RSDZTD"[current->state];
	psinfo.pr_zomb = psinfo.pr_sname == 'Z';
	psinfo.pr_nice = current->priority-15;
	psinfo.pr_flag = current->flags;
	psinfo.pr_uid = current->uid;
	psinfo.pr_gid = current->gid;
	{
		int i, len;

		set_fs(fs);
		
		len = current->mm->arg_end - current->mm->arg_start;
		len = len >= ELF_PRARGSZ ? ELF_PRARGSZ : len;
		memcpy_fromfs(&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 (&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, PAGE_SIZE);
	
	/* 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;

		if (!maydump(vma))
			continue;
		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 = sz;
		phdr.p_memsz = sz;
		offset += sz;
		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 = PAGE_SIZE;

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

	for(i = 0; i < numnote; i++)
		if (!writenote(&notes[i], &file))
			goto close_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;
		
		if (!maydump(vma))
			continue;
		i++;
#ifdef DEBUG
		printk("elf_core_dump: writing %08lx %lx\n", addr, len);
#endif
		DUMP_WRITE((void *)addr, len);
	}

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

 close_coredump:
	if (file.f_op->release)
		file.f_op->release(inode,&file);

 end_coredump:
	set_fs(fs);
	iput(inode);
#ifndef CONFIG_BINFMT_ELF
	MOD_DEC_USE_COUNT;
#endif
	return has_dumped;
}

#ifdef MODULE
char kernel_version[] = UTS_RELEASE;

int init_module(void) {
	/* Install the COFF, ELF and XOUT loaders.
	 * N.B. We *rely* on the table being the right size with the
	 * right number of free slots...
	 */
	register_binfmt(&elf_format);
	return 0;
}


void cleanup_module( void) {
	
	if (MOD_IN_USE)
		printk(KERN_INFO "iBCS: module is in use, remove delayed\n");

	/* Remove the COFF and ELF loaders. */
	unregister_binfmt(&elf_format);
}
#endif