fs/binfmt_elf.c - pub/scm/linux/kernel/git/nico/archive - Git at Google

 /*
  * linux/fs/binfmt_elf.c
  */
 #include <linux/fs.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 <asm/segment.h>

 asmlinkage int sys_exit(int exit_code);
 asmlinkage int sys_close(unsigned fd);
 asmlinkage int sys_open(const char *, int, int);
 asmlinkage int sys_brk(unsigned long);

 #define DLINFO_ITEMS 8

 #include <linux/elf.h>

 /* 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(int elf_bss){
   unsigned int fpnt, nbyte;

   if(elf_bss & 0xfff) {

     nbyte = (PAGE_SIZE - (elf_bss & 0xfff)) & 0xfff;
     if(nbyte){
       verify_area(VERIFY_WRITE, (void *) elf_bss, nbyte);

       fpnt = elf_bss;
       while(fpnt & 0xfff) put_fs_byte(0, fpnt++);
     };
   };
 }

 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_PRIVATE|PAGE_DIRTY;
 		mpnt->vm_share = NULL;
 		mpnt->vm_inode = NULL;
 		mpnt->vm_offset = 0;
 		mpnt->vm_ops = NULL;
 		insert_vm_struct(current, mpnt);
 		current->stk_vma = mpnt;
 	}
 	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->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->arg_end = current->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->env_end = (unsigned long) p;
 	return sp;
 }


 /* This is much more generalized than the library routine read function,
    so we keep this separate.  Techincally 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->bmap ||
 	    !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->filp[elf_exec_fileno];

 	eppnt = elf_phdata;
 	for(i=0; i<interp_elf_ex->e_phnum; i++, eppnt++)
 	  if(eppnt->p_type == PT_LOAD) {
 	    error = do_mmap(file,
 			    eppnt->p_vaddr & 0xfffff000,
 			    eppnt->p_filesz + (eppnt->p_vaddr & 0xfff),
 			    PROT_READ | PROT_WRITE | PROT_EXEC,
 			    MAP_PRIVATE | (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->brk = interp_ex->a_bss +
     (current->end_data = interp_ex->a_data +
      (current->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

 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;
 	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];

 	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)
 		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)){
 		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);
 		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);
 		return elf_exec_fileno;
 	}

 	file = current->filp[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 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);
 			  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);
 			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);
 		    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);
 			return -E2BIG;
 		}
 	}

 	/* OK, This is the point of no return */
 	flush_old_exec(bprm);

 	current->end_data = 0;
 	current->end_code = 0;
 	current->start_mmap = ELF_START_MMAP;
 	current->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->rss = 0;
 	bprm->p += change_ldt(0, bprm->page);
 	current->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);
 		    return 0;
 		  };
 		};


 		if(elf_ppnt->p_type == PT_LOAD) {
 			error = do_mmap(file,
 					elf_ppnt->p_vaddr & 0xfffff000,
 					elf_ppnt->p_filesz + (elf_ppnt->p_vaddr & 0xfff),
 					PROT_READ | PROT_WRITE | PROT_EXEC,
 					MAP_FIXED | MAP_PRIVATE,
 					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(!elf_interpreter) sys_close(elf_exec_fileno);
 	current->elf_executable = 1;
 	current->executable = bprm->inode;
 	bprm->inode->i_count++;
 #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->arg_start += strlen(passed_fileno) + 1;
 	current->start_brk = current->brk = elf_brk;
 	current->end_code = end_code;
 	current->start_code = start_code;
 	current->end_data = end_data;
 	current->start_stack = bprm->p;
 	current->suid = current->euid = bprm->e_uid;
 	current->sgid = current->egid = bprm->e_gid;

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

 	padzero(elf_bss);

 	/* 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);

 	regs->eip = elf_entry;		/* eip, magic happens :-) */
 	regs->esp = bprm->p;			/* stack pointer */
 	if (current->flags & PF_PTRACED)
 		send_sig(SIGTRAP, current, 0);
 	return 0;
 }

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

 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;

 	len = 0;
 	file = current->filp[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);
 		return -EACCES;
 	}
 	set_fs(USER_DS);

 	if (elf_ex.e_ident[0] != 0x7f ||
 	    strncmp(&elf_ex.e_ident[1], "ELF",3) != 0)
 		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->bmap ||
 	    !inode->i_op->default_file_ops->mmap)){
 		return -ENOEXEC;
 	};

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

 	if(sizeof(struct elf_phdr) * elf_ex.e_phnum > PAGE_SIZE)
 		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);
 		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,
 			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);
 		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);
 	return 0;
 }
	/*
	* linux/fs/binfmt_elf.c
	*/
	#include <linux/fs.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 <asm/segment.h>

	asmlinkage int sys_exit(int exit_code);
	asmlinkage int sys_close(unsigned fd);
	asmlinkage int sys_open(const char *, int, int);
	asmlinkage int sys_brk(unsigned long);

	#define DLINFO_ITEMS 8

	#include <linux/elf.h>

	/* 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(int elf_bss){
	unsigned int fpnt, nbyte;

	if(elf_bss & 0xfff) {

	nbyte = (PAGE_SIZE - (elf_bss & 0xfff)) & 0xfff;
	if(nbyte){
	verify_area(VERIFY_WRITE, (void *) elf_bss, nbyte);

	fpnt = elf_bss;
	while(fpnt & 0xfff) put_fs_byte(0, fpnt++);
	};
	};
	}

	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_PRIVATE\|PAGE_DIRTY;
	mpnt->vm_share = NULL;
	mpnt->vm_inode = NULL;
	mpnt->vm_offset = 0;
	mpnt->vm_ops = NULL;
	insert_vm_struct(current, mpnt);
	current->stk_vma = mpnt;
	}
	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->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->arg_end = current->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->env_end = (unsigned long) p;
	return sp;
	}


	/* This is much more generalized than the library routine read function,
	so we keep this separate. Techincally 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->bmap \|\|
	!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->filp[elf_exec_fileno];

	eppnt = elf_phdata;
	for(i=0; i<interp_elf_ex->e_phnum; i++, eppnt++)
	if(eppnt->p_type == PT_LOAD) {
	error = do_mmap(file,
	eppnt->p_vaddr & 0xfffff000,
	eppnt->p_filesz + (eppnt->p_vaddr & 0xfff),
	PROT_READ \| PROT_WRITE \| PROT_EXEC,
	MAP_PRIVATE \| (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->brk = interp_ex->a_bss +
	(current->end_data = interp_ex->a_data +
	(current->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

	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;
	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];

	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)
	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)){
	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);
	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);
	return elf_exec_fileno;
	}

	file = current->filp[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 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);
	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);
	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);
	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);
	return -E2BIG;
	}
	}

	/* OK, This is the point of no return */
	flush_old_exec(bprm);

	current->end_data = 0;
	current->end_code = 0;
	current->start_mmap = ELF_START_MMAP;
	current->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->rss = 0;
	bprm->p += change_ldt(0, bprm->page);
	current->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);
	return 0;
	};
	};


	if(elf_ppnt->p_type == PT_LOAD) {
	error = do_mmap(file,
	elf_ppnt->p_vaddr & 0xfffff000,
	elf_ppnt->p_filesz + (elf_ppnt->p_vaddr & 0xfff),
	PROT_READ \| PROT_WRITE \| PROT_EXEC,
	MAP_FIXED \| MAP_PRIVATE,
	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(!elf_interpreter) sys_close(elf_exec_fileno);
	current->elf_executable = 1;
	current->executable = bprm->inode;
	bprm->inode->i_count++;
	#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->arg_start += strlen(passed_fileno) + 1;
	current->start_brk = current->brk = elf_brk;
	current->end_code = end_code;
	current->start_code = start_code;
	current->end_data = end_data;
	current->start_stack = bprm->p;
	current->suid = current->euid = bprm->e_uid;
	current->sgid = current->egid = bprm->e_gid;

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

	padzero(elf_bss);

	/* 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);

	regs->eip = elf_entry; /* eip, magic happens :-) */
	regs->esp = bprm->p; /* stack pointer */
	if (current->flags & PF_PTRACED)
	send_sig(SIGTRAP, current, 0);
	return 0;
	}

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

	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;

	len = 0;
	file = current->filp[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);
	return -EACCES;
	}
	set_fs(USER_DS);

	if (elf_ex.e_ident[0] != 0x7f \|\|
	strncmp(&elf_ex.e_ident[1], "ELF",3) != 0)
	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->bmap \|\|
	!inode->i_op->default_file_ops->mmap)){
	return -ENOEXEC;
	};

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

	if(sizeof(struct elf_phdr) * elf_ex.e_phnum > PAGE_SIZE)
	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);
	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,
	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);
	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);
	return 0;
	}