text: /*
   *  linux/fs/exec.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   */
  
  /*
   * #!-checking implemented by tytso.
   */
  
  /*
   * Demand-loading implemented 01.12.91 - no need to read anything but
   * the header into memory. The inode of the executable is put into
   * "current->executable", and page faults do the actual loading. Clean.
   *
   * Once more I can proudly say that linux stood up to being changed: it
   * was less than 2 hours work to get demand-loading completely implemented.
   *
   * Demand loading changed July 1993 by Eric Youngdale.   Use mmap instead,
   * current->executable is only used by the procfs.  This allows a dispatch
   * table to check for several different types  of binary formats.  We keep
   * trying until we recognize the file or we run out of supported binary
   * formats. 
   */
  
  #include <linux/fs.h>
  #include <linux/sched.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/mman.h>
  #include <linux/a.out.h>
  #include <linux/errno.h>
  #include <linux/signal.h>
  #include <linux/string.h>
  #include <linux/stat.h>
  #include <linux/fcntl.h>
  #include <linux/ptrace.h>
  #include <linux/user.h>
  #include <linux/malloc.h>
  #include <linux/binfmts.h>
  #include <linux/personality.h>
  
  #include <asm/system.h>
  #include <asm/segment.h>
  #include <asm/pgtable.h>
  
  #include <linux/config.h>
  
  asmlinkage int sys_exit(int exit_code);
  asmlinkage int sys_brk(unsigned long);
  
  static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
  static int load_aout_library(int fd);
  static int aout_core_dump(long signr, struct pt_regs * regs);
  
  extern void dump_thread(struct pt_regs *, struct user *);
  
  /*
   * Here are the actual binaries that will be accepted:
   * add more with "register_binfmt()"..
   */
  extern struct linux_binfmt elf_format;
  
  static struct linux_binfmt aout_format = {
  #ifndef CONFIG_BINFMT_ELF
   	NULL, NULL, load_aout_binary, load_aout_library, aout_core_dump
  #else
   	&elf_format, NULL, load_aout_binary, load_aout_library, aout_core_dump
  #endif
  };
  
  static struct linux_binfmt *formats = &aout_format;
  
  int register_binfmt(struct linux_binfmt * fmt)
  {
  	struct linux_binfmt ** tmp = &formats;
  
  	if (!fmt)
  		return -EINVAL;
  	if (fmt->next)
  		return -EBUSY;
  	while (*tmp) {
  		if (fmt == *tmp)
  			return -EBUSY;
  		tmp = &(*tmp)->next;
  	}
  	*tmp = fmt;
  	return 0;	
  }
  
  int unregister_binfmt(struct linux_binfmt * fmt)
  {
  	struct linux_binfmt ** tmp = &formats;
  
  	while (*tmp) {
  		if (fmt == *tmp) {
  			*tmp = fmt->next;
  			return 0;
  		}
  		tmp = &(*tmp)->next;
  	}
  	return -EINVAL;
  }
  
  int open_inode(struct inode * inode, int mode)
  {
  	int error, fd;
  	struct file *f, **fpp;
  
  	if (!inode->i_op || !inode->i_op->default_file_ops)
  		return -EINVAL;
  	f = get_empty_filp();
  	if (!f)
  		return -ENFILE;
  	fd = 0;
  	fpp = current->files->fd;
  	for (;;) {
  		if (!*fpp)
  			break;
  		if (++fd >= NR_OPEN) {
  			f->f_count--;
  			return -EMFILE;
  		}
  		fpp++;
  	}
  	*fpp = f;
  	f->f_flags = mode;
  	f->f_mode = (mode+1) & O_ACCMODE;
  	f->f_inode = inode;
  	f->f_pos = 0;
  	f->f_reada = 0;
  	f->f_op = inode->i_op->default_file_ops;
  	if (f->f_op->open) {
  		error = f->f_op->open(inode,f);
  		if (error) {
  			*fpp = NULL;
  			f->f_count--;
  			return error;
  		}
  	}
  	inode->i_count++;
  	return fd;
  }
  
  /*
   * These are the only things you should do on a core-file: use only these
   * macros to write out all the necessary info.
   */
  #define DUMP_WRITE(addr,nr) \
  while (file.f_op->write(inode,&file,(char *)(addr),(nr)) != (nr)) goto close_coredump
  
  #define DUMP_SEEK(offset) \
  if (file.f_op->lseek) { \
  	if (file.f_op->lseek(inode,&file,(offset),0) != (offset)) \
   		goto close_coredump; \
  } else file.f_pos = (offset)		
  
  /*
   * Routine writes a core dump image in the current directory.
   * Currently only a stub-function.
   *
   * Note that setuid/setgid files won't make a core-dump if the uid/gid
   * changed due to the set[u|g]id. It's enforced by the "current->dumpable"
   * field, which also makes sure the core-dumps won't be recursive if the
   * dumping of the process results in another error..
   */
  static int aout_core_dump(long signr, struct pt_regs * regs)
  {
  	struct inode * inode = NULL;
  	struct file file;
  	unsigned short fs;
  	int has_dumped = 0;
  	char corefile[6+sizeof(current->comm)];
  	unsigned long dump_start, dump_size;
  	struct user dump;
  
  	if (!current->dumpable)
  		return 0;
  	current->dumpable = 0;
  
  /* See if we have enough room to write the upage.  */
  	if (current->rlim[RLIMIT_CORE].rlim_cur < PAGE_SIZE)
  		return 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;
  	if (get_write_access(inode))
  		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 done_coredump;
  	if (!file.f_op->write)
  		goto close_coredump;
  	has_dumped = 1;
         	strncpy(dump.u_comm, current->comm, sizeof(current->comm));
  	dump.u_ar0 = (struct pt_regs *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
  	dump.signal = signr;
  	dump_thread(regs, &dump);
  
  /* If the size of the dump file exceeds the rlimit, then see what would happen
     if we wrote the stack, but not the data area.  */
  	if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
  	    current->rlim[RLIMIT_CORE].rlim_cur)
  		dump.u_dsize = 0;
  
  /* Make sure we have enough room to write the stack and data areas. */
  	if ((dump.u_ssize+1) * PAGE_SIZE >
  	    current->rlim[RLIMIT_CORE].rlim_cur)
  		dump.u_ssize = 0;
  
  	set_fs(KERNEL_DS);
  /* struct user */
  	DUMP_WRITE(&dump,sizeof(dump));
  /* Now dump all of the user data.  Include malloced stuff as well */
  	DUMP_SEEK(PAGE_SIZE);
  /* now we start writing out the user space info */
  	set_fs(USER_DS);
  /* Dump the data area */
  	if (dump.u_dsize != 0) {
  		dump_start = dump.u_tsize << 12;
  		dump_size = dump.u_dsize << 12;
  		DUMP_WRITE(dump_start,dump_size);
  	}
  /* Now prepare to dump the stack area */
  	if (dump.u_ssize != 0) {
  		dump_start = dump.start_stack;
  		dump_size = dump.u_ssize << 12;
  		DUMP_WRITE(dump_start,dump_size);
  	}
  /* Finally dump the task struct.  Not be used by gdb, but could be useful */
  	set_fs(KERNEL_DS);
  	DUMP_WRITE(current,sizeof(*current));
  close_coredump:
  	if (file.f_op->release)
  		file.f_op->release(inode,&file);
  done_coredump:
  	put_write_access(inode);
  end_coredump:
  	set_fs(fs);
  	iput(inode);
  	return has_dumped;
  }
  
  /*
   * Note that a shared library must be both readable and executable due to
   * security reasons.
   *
   * Also note that we take the address to load from from the file itself.
   */
  asmlinkage int sys_uselib(const char * library)
  {
  	int fd, retval;
  	struct file * file;
  	struct linux_binfmt * fmt;
  
  	fd = sys_open(library, 0, 0);
  	if (fd < 0)
  		return fd;
  	file = current->files->fd[fd];
  	retval = -ENOEXEC;
  	if (file && file->f_inode && file->f_op && file->f_op->read) {
  		for (fmt = formats ; fmt ; fmt = fmt->next) {
  			int (*fn)(int) = fmt->load_shlib;
  			if (!fn)
  				break;
  			retval = fn(fd);
  			if (retval != -ENOEXEC)
  				break;
  		}
  	}
  	sys_close(fd);
    	return retval;
  }
  
  /*
   * create_tables() parses the env- and arg-strings in new user
   * memory and creates the pointer tables from them, and puts their
   * addresses on the "stack", returning the new stack pointer value.
   */
  unsigned long * create_tables(char * p,int argc,int envc,int ibcs)
  {
  	unsigned long *argv,*envp;
  	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;
  		mpnt->vm_flags = VM_STACK_FLAGS;
  		mpnt->vm_ops = NULL;
  		mpnt->vm_offset = 0;
  		mpnt->vm_inode = NULL;
  		mpnt->vm_pte = 0;
  		insert_vm_struct(current, mpnt);
  	}
  	sp = (unsigned long *) (0xfffffffc & (unsigned long) p);
  	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);
  	}
  	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;
  }
  
  /*
   * count() counts the number of arguments/envelopes
   *
   * We also do some limited EFAULT checking: this isn't complete, but
   * it does cover most cases. I'll have to do this correctly some day..
   */
  static int count(char ** argv)
  {
  	int error, i = 0;
  	char ** tmp, *p;
  
  	if ((tmp = argv) != NULL) {
  		error = verify_area(VERIFY_READ, tmp, sizeof(char *));
  		if (error)
  			return error;
  		while ((p = (char *) get_fs_long((unsigned long *) (tmp++))) != NULL) {
  			i++;
  			error = verify_area(VERIFY_READ, p, 1);
  			if (error)
  				return error;
  		}
  	}
  	return i;
  }
  
  /*
   * 'copy_string()' copies argument/envelope strings from user
   * memory to free pages in kernel mem. These are in a format ready
   * to be put directly into the top of new user memory.
   *
   * Modified by TYT, 11/24/91 to add the from_kmem argument, which specifies
   * whether the string and the string array are from user or kernel segments:
   * 
   * from_kmem     argv *        argv **
   *    0          user space    user space
   *    1          kernel space  user space
   *    2          kernel space  kernel space
   * 
   * We do this by playing games with the fs segment register.  Since it
   * is expensive to load a segment register, we try to avoid calling
   * set_fs() unless we absolutely have to.
   */
  unsigned long copy_strings(int argc,char ** argv,unsigned long *page,
  		unsigned long p, int from_kmem)
  {
  	char *tmp, *pag = NULL;
  	int len, offset = 0;
  	unsigned long old_fs, new_fs;
  
  	if (!p)
  		return 0;	/* bullet-proofing */
  	new_fs = get_ds();
  	old_fs = get_fs();
  	if (from_kmem==2)
  		set_fs(new_fs);
  	while (argc-- > 0) {
  		if (from_kmem == 1)
  			set_fs(new_fs);
  		if (!(tmp = (char *)get_fs_long(((unsigned long *)argv)+argc)))
  			panic("VFS: argc is wrong");
  		if (from_kmem == 1)
  			set_fs(old_fs);
  		len=0;		/* remember zero-padding */
  		do {
  			len++;
  		} while (get_fs_byte(tmp++));
  		if (p < len) {	/* this shouldn't happen - 128kB */
  			set_fs(old_fs);
  			return 0;
  		}
  		while (len) {
  			--p; --tmp; --len;
  			if (--offset < 0) {
  				offset = p % PAGE_SIZE;
  				if (from_kmem==2)
  					set_fs(old_fs);
  				if (!(pag = (char *) page[p/PAGE_SIZE]) &&
  				    !(pag = (char *) page[p/PAGE_SIZE] =
  				      (unsigned long *) get_free_page(GFP_USER))) 
  					return 0;
  				if (from_kmem==2)
  					set_fs(new_fs);
  
  			}
  			*(pag + offset) = get_fs_byte(tmp);
  		}
  	}
  	if (from_kmem==2)
  		set_fs(old_fs);
  	return p;
  }
  
  unsigned long setup_arg_pages(unsigned long text_size,unsigned long * page)
  {
  	unsigned long code_limit,data_limit,code_base,data_base;
  	int i;
  
  	code_limit = TASK_SIZE;
  	data_limit = TASK_SIZE;
  	code_base = data_base = 0;
  	current->mm->start_code = code_base;
  	data_base += data_limit;
  	for (i=MAX_ARG_PAGES-1 ; i>=0 ; i--) {
  		data_base -= PAGE_SIZE;
  		if (page[i]) {
  			current->mm->rss++;
  			put_dirty_page(current,page[i],data_base);
  		}
  	}
  	return data_limit;
  }
  
  /*
   * Read in the complete executable. This is used for "-N" files
   * that aren't on a block boundary, and for files on filesystems
   * without bmap support.
   */
  int read_exec(struct inode *inode, unsigned long offset,
  	char * addr, unsigned long count)
  {
  	struct file file;
  	int result = -ENOEXEC;
  
  	if (!inode->i_op || !inode->i_op->default_file_ops)
  		goto end_readexec;
  	file.f_mode = 1;
  	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_readexec;
  	if (!file.f_op || !file.f_op->read)
  		goto close_readexec;
  	if (file.f_op->lseek) {
  		if (file.f_op->lseek(inode,&file,offset,0) != offset)
   			goto close_readexec;
  	} else
  		file.f_pos = offset;
  	if (get_fs() == USER_DS) {
  		result = verify_area(VERIFY_WRITE, addr, count);
  		if (result)
  			goto close_readexec;
  	}
  	result = file.f_op->read(inode, &file, addr, count);
  close_readexec:
  	if (file.f_op->release)
  		file.f_op->release(inode,&file);
  end_readexec:
  	return result;
  }
  
  
  /*
   * This function flushes out all traces of the currently running executable so
   * that a new one can be started
   */
  
  void flush_old_exec(struct linux_binprm * bprm)
  {
  	int i;
  	int ch;
  	char * name;
  
  	current->dumpable = 1;
  	name = bprm->filename;
  	for (i=0; (ch = *(name++)) != '\0';) {
  		if (ch == '/')
  			i = 0;
  		else
  			if (i < 15)
  				current->comm[i++] = ch;
  	}
  	current->comm[i] = '\0';
  
  	/* Release all of the old mmap stuff. */
  	exit_mmap(current);
  
  	flush_thread();
  
  	if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || 
  	    permission(bprm->inode,MAY_READ))
  		current->dumpable = 0;
  	current->signal = 0;
  	for (i=0 ; i<32 ; i++) {
  		current->sigaction[i].sa_mask = 0;
  		current->sigaction[i].sa_flags = 0;
  		if (current->sigaction[i].sa_handler != SIG_IGN)
  			current->sigaction[i].sa_handler = NULL;
  	}
  	for (i=0 ; i<NR_OPEN ; i++)
  		if (FD_ISSET(i,&current->files->close_on_exec))
  			sys_close(i);
  	FD_ZERO(&current->files->close_on_exec);
  	clear_page_tables(current);
  	if (last_task_used_math == current)
  		last_task_used_math = NULL;
  	current->used_math = 0;
  }
  
  /*
   * sys_execve() executes a new program.
   */
  int do_execve(char * filename, char ** argv, char ** envp, struct pt_regs * regs)
  {
  	struct linux_binprm bprm;
  	struct linux_binfmt * fmt;
  	unsigned long old_fs;
  	int i;
  	int retval;
  	int sh_bang = 0;
  
  	bprm.p = PAGE_SIZE*MAX_ARG_PAGES-4;
  	for (i=0 ; i<MAX_ARG_PAGES ; i++)	/* clear page-table */
  		bprm.page[i] = 0;
  	retval = open_namei(filename, 0, 0, &bprm.inode, NULL);
  	if (retval)
  		return retval;
  	bprm.filename = filename;
  	if ((bprm.argc = count(argv)) < 0)
  		return bprm.argc;
  	if ((bprm.envc = count(envp)) < 0)
  		return bprm.envc;
  	
  restart_interp:
  	if (!S_ISREG(bprm.inode->i_mode)) {	/* must be regular file */
  		retval = -EACCES;
  		goto exec_error2;
  	}
  	if (IS_NOEXEC(bprm.inode)) {		/* FS mustn't be mounted noexec */
  		retval = -EPERM;
  		goto exec_error2;
  	}
  	if (!bprm.inode->i_sb) {
  		retval = -EACCES;
  		goto exec_error2;
  	}
  	i = bprm.inode->i_mode;
  	if (IS_NOSUID(bprm.inode) && (((i & S_ISUID) && bprm.inode->i_uid != current->
  	    euid) || ((i & S_ISGID) && !in_group_p(bprm.inode->i_gid))) && !suser()) {
  		retval = -EPERM;
  		goto exec_error2;
  	}
  	/* make sure we don't let suid, sgid files be ptraced. */
  	if (current->flags & PF_PTRACED) {
  		bprm.e_uid = current->euid;
  		bprm.e_gid = current->egid;
  	} else {
  		bprm.e_uid = (i & S_ISUID) ? bprm.inode->i_uid : current->euid;
  		bprm.e_gid = (i & S_ISGID) ? bprm.inode->i_gid : current->egid;
  	}
  	if ((retval = permission(bprm.inode, MAY_EXEC)) != 0)
  		goto exec_error2;
  	if (!(bprm.inode->i_mode & 0111) && fsuser()) {
  		retval = -EACCES;
  		goto exec_error2;
  	}
  	/* better not execute files which are being written to */
  	if (bprm.inode->i_wcount > 0) {
  		retval = -ETXTBSY;
  		goto exec_error2;
  	}
  	memset(bprm.buf,0,sizeof(bprm.buf));
  	old_fs = get_fs();
  	set_fs(get_ds());
  	retval = read_exec(bprm.inode,0,bprm.buf,128);
  	set_fs(old_fs);
  	if (retval < 0)
  		goto exec_error2;
  	if ((bprm.buf[0] == '#') && (bprm.buf[1] == '!') && (!sh_bang)) {
  		/*
  		 * This section does the #! interpretation.
  		 * Sorta complicated, but hopefully it will work.  -TYT
  		 */
  
  		char *cp, *interp, *i_name, *i_arg;
  
  		iput(bprm.inode);
  		bprm.buf[127] = '\0';
  		if ((cp = strchr(bprm.buf, '\n')) == NULL)
  			cp = bprm.buf+127;
  		*cp = '\0';
  		while (cp > bprm.buf) {
  			cp--;
  			if ((*cp == ' ') || (*cp == '\t'))
  				*cp = '\0';
  			else
  				break;
  		}
  		for (cp = bprm.buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
  		if (!cp || *cp == '\0') {
  			retval = -ENOEXEC; /* No interpreter name found */
  			goto exec_error1;
  		}
  		interp = i_name = cp;
  		i_arg = 0;
  		for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++) {
   			if (*cp == '/')
  				i_name = cp+1;
  		}
  		while ((*cp == ' ') || (*cp == '\t'))
  			*cp++ = '\0';
  		if (*cp)
  			i_arg = cp;
  		/*
  		 * OK, we've parsed out the interpreter name and
  		 * (optional) argument.
  		 */
  		if (sh_bang++ == 0) {
  			bprm.p = copy_strings(bprm.envc, envp, bprm.page, bprm.p, 0);
  			bprm.p = copy_strings(--bprm.argc, argv+1, bprm.page, bprm.p, 0);
  		}
  		/*
  		 * Splice in (1) the interpreter's name for argv[0]
  		 *           (2) (optional) argument to interpreter
  		 *           (3) filename of shell script
  		 *
  		 * This is done in reverse order, because of how the
  		 * user environment and arguments are stored.
  		 */
  		bprm.p = copy_strings(1, &bprm.filename, bprm.page, bprm.p, 2);
  		bprm.argc++;
  		if (i_arg) {
  			bprm.p = copy_strings(1, &i_arg, bprm.page, bprm.p, 2);
  			bprm.argc++;
  		}
  		bprm.p = copy_strings(1, &i_name, bprm.page, bprm.p, 2);
  		bprm.argc++;
  		if (!bprm.p) {
  			retval = -E2BIG;
  			goto exec_error1;
  		}
  		/*
  		 * OK, now restart the process with the interpreter's inode.
  		 * Note that we use open_namei() as the name is now in kernel
  		 * space, and we don't need to copy it.
  		 */
  		retval = open_namei(interp, 0, 0, &bprm.inode, NULL);
  		if (retval)
  			goto exec_error1;
  		goto restart_interp;
  	}
  	if (!sh_bang) {
  		bprm.p = copy_strings(bprm.envc,envp,bprm.page,bprm.p,0);
  		bprm.p = copy_strings(bprm.argc,argv,bprm.page,bprm.p,0);
  		if (!bprm.p) {
  			retval = -E2BIG;
  			goto exec_error2;
  		}
  	}
  
  	bprm.sh_bang = sh_bang;
  	for (fmt = formats ; fmt ; fmt = fmt->next) {
  		int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
  		if (!fn)
  			break;
  		retval = fn(&bprm, regs);
  		if (retval >= 0) {
  			iput(bprm.inode);
  			current->did_exec = 1;
  			return retval;
  		}
  		if (retval != -ENOEXEC)
  			break;
  	}
  exec_error2:
  	iput(bprm.inode);
  exec_error1:
  	for (i=0 ; i<MAX_ARG_PAGES ; i++)
  		free_page(bprm.page[i]);
  	return(retval);
  }
  
  static void set_brk(unsigned long start, unsigned long end)
  {
  	start = PAGE_ALIGN(start);
  	end = PAGE_ALIGN(end);
  	if (end <= start)
  		return;
  	do_mmap(NULL, start, end - start,
  		PROT_READ | PROT_WRITE | PROT_EXEC,
  		MAP_FIXED | MAP_PRIVATE, 0);
  }
  
  /*
   * These are the functions used to load a.out style executables and shared
   * libraries.  There is no binary dependent code anywhere else.
   */
  
  static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
  {
  	struct exec ex;
  	struct file * file;
  	int fd, error;
  	unsigned long p = bprm->p;
  	unsigned long fd_offset;
  
  	ex = *((struct exec *) bprm->buf);		/* exec-header */
  	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && 
  	     N_MAGIC(ex) != QMAGIC) ||
  	    ex.a_trsize || ex.a_drsize ||
  	    bprm->inode->i_size < ex.a_text+ex.a_data+ex.a_syms+N_TXTOFF(ex)) {
  		return -ENOEXEC;
  	}
  
  	current->personality = PER_LINUX;
  	fd_offset = N_TXTOFF(ex);
  	if (N_MAGIC(ex) == ZMAGIC && fd_offset != BLOCK_SIZE) {
  		printk(KERN_NOTICE "N_TXTOFF != BLOCK_SIZE. See a.out.h.\n");
  		return -ENOEXEC;
  	}
  
  	if (N_MAGIC(ex) == ZMAGIC && ex.a_text &&
  	    (fd_offset < bprm->inode->i_sb->s_blocksize)) {
  		printk(KERN_NOTICE "N_TXTOFF < BLOCK_SIZE. Please convert binary.\n");
  		return -ENOEXEC;
  	}
  
  	/* OK, This is the point of no return */
  	flush_old_exec(bprm);
  
  	current->mm->brk = ex.a_bss +
  		(current->mm->start_brk =
  		(current->mm->end_data = ex.a_data +
  		(current->mm->end_code = ex.a_text +
  		(current->mm->start_code = N_TXTADDR(ex)))));
  	current->mm->rss = 0;
  	current->mm->mmap = NULL;
  	current->suid = current->euid = current->fsuid = bprm->e_uid;
  	current->sgid = current->egid = current->fsgid = bprm->e_gid;
  	if (N_MAGIC(ex) == OMAGIC) {
  		do_mmap(NULL, 0, ex.a_text+ex.a_data,
  			PROT_READ|PROT_WRITE|PROT_EXEC,
  			MAP_FIXED|MAP_PRIVATE, 0);
  		read_exec(bprm->inode, 32, (char *) 0, ex.a_text+ex.a_data);
  	} else {
  		if (ex.a_text & 0xfff || ex.a_data & 0xfff)
  			printk(KERN_NOTICE "executable not page aligned\n");
  		
  		fd = open_inode(bprm->inode, O_RDONLY);
  		
  		if (fd < 0)
  			return fd;
  		file = current->files->fd[fd];
  		if (!file->f_op || !file->f_op->mmap) {
  			sys_close(fd);
  			do_mmap(NULL, 0, ex.a_text+ex.a_data,
  				PROT_READ|PROT_WRITE|PROT_EXEC,
  				MAP_FIXED|MAP_PRIVATE, 0);
  			read_exec(bprm->inode, fd_offset,
  				  (char *) N_TXTADDR(ex), ex.a_text+ex.a_data);
  			goto beyond_if;
  		}
  
  		error = do_mmap(file, N_TXTADDR(ex), ex.a_text,
  			PROT_READ | PROT_EXEC,
  			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
  			fd_offset);
  
  		if (error != N_TXTADDR(ex)) {
  			sys_close(fd);
  			send_sig(SIGKILL, current, 0);
  			return error;
  		}
  		
   		error = do_mmap(file, N_TXTADDR(ex) + ex.a_text, ex.a_data,
  				PROT_READ | PROT_WRITE | PROT_EXEC,
  				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
  				fd_offset + ex.a_text);
  		sys_close(fd);
  		if (error != N_TXTADDR(ex) + ex.a_text) {
  			send_sig(SIGKILL, current, 0);
  			return error;
  		}
  	}
  beyond_if:
  	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 = &aout_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)++;
  
  	set_brk(current->mm->start_brk, current->mm->brk);
  	
  	p += setup_arg_pages(ex.a_text,bprm->page);
  	p -= MAX_ARG_PAGES*PAGE_SIZE;
  	p = (unsigned long)create_tables((char *)p,
  					bprm->argc, bprm->envc,
  					current->personality != PER_LINUX);
  	current->mm->start_stack = p;
  	start_thread(regs, ex.a_entry, p);
  	if (current->flags & PF_PTRACED)
  		send_sig(SIGTRAP, current, 0);
  	return 0;
  }
  
  
  static int load_aout_library(int fd)
  {
          struct file * file;
  	struct exec ex;
  	struct  inode * inode;
  	unsigned int len;
  	unsigned int bss;
  	unsigned int start_addr;
  	int error;
  	
  	file = current->files->fd[fd];
  	inode = file->f_inode;
  	
  	set_fs(KERNEL_DS);
  	if (file->f_op->read(inode, file, (char *) &ex, sizeof(ex)) != sizeof(ex)) {
  		return -EACCES;
  	}
  	set_fs(USER_DS);
  	
  	/* We come in here for the regular a.out style of shared libraries */
  	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || ex.a_trsize ||
  	    ex.a_drsize || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
  	    inode->i_size < ex.a_text+ex.a_data+ex.a_syms+N_TXTOFF(ex)) {
  		return -ENOEXEC;
  	}
  	if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) && 
  	    (N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
  		printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
  		return -ENOEXEC;
  	}
  	
  	if (N_FLAGS(ex)) return -ENOEXEC;
  
  	/* For  QMAGIC, the starting address is 0x20 into the page.  We mask
  	   this off to get the starting address for the page */
  
  	start_addr =  ex.a_entry & 0xfffff000;
  
  	/* Now use mmap to map the library into memory. */
  	error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
  			PROT_READ | PROT_WRITE | PROT_EXEC,
  			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
  			N_TXTOFF(ex));
  	if (error != start_addr)
  		return error;
  	len = PAGE_ALIGN(ex.a_text + ex.a_data);
  	bss = ex.a_text + ex.a_data + ex.a_bss;
  	if (bss > len)
  		do_mmap(NULL, start_addr + len, bss-len,
  			PROT_READ|PROT_WRITE|PROT_EXEC,
  			MAP_PRIVATE|MAP_FIXED, 0);
  	return 0;
  }
  