[mirror_ubuntu-bionic-kernel.git] / fs / binfmt_em86.c

/*
 *  linux/fs/binfmt_em86.c
 *
 *  Based on linux/fs/binfmt_script.c
 *  Copyright (C) 1996  Martin von Löwis
 *  original #!-checking implemented by tytso.
 *
 *  em86 changes Copyright (C) 1997  Jim Paradis
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/binfmts.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/errno.h>


#define EM86_INTERP	"/usr/bin/em86"
#define EM86_I_NAME	"em86"

static int load_em86(struct linux_binprm *bprm)
{
	char *interp, *i_name, *i_arg;
	struct file * file;
	int retval;
	struct elfhdr	elf_ex;

	/* Make sure this is a Linux/Intel ELF executable... */
	elf_ex = *((struct elfhdr *)bprm->buf);

	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		return  -ENOEXEC;

	/* First of all, some simple consistency checks */
	if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
		(!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) ||
		!bprm->file->f_op->mmap) {
			return -ENOEXEC;
	}

	allow_write_access(bprm->file);
	fput(bprm->file);
	bprm->file = NULL;

	/* Unlike in the script case, we don't have to do any hairy
	 * parsing to find our interpreter... it's hardcoded!
	 */
	interp = EM86_INTERP;
	i_name = EM86_I_NAME;
	i_arg = NULL;		/* We reserve the right to add an arg later */

	/*
	 * Splice in (1) the interpreter's name for argv[0]
	 *           (2) (optional) argument to interpreter
	 *           (3) filename of emulated file (replace argv[0])
	 *
	 * This is done in reverse order, because of how the
	 * user environment and arguments are stored.
	 */
	remove_arg_zero(bprm);
	retval = copy_strings_kernel(1, &bprm->filename, bprm);
	if (retval < 0) return retval; 
	bprm->argc++;
	if (i_arg) {
		retval = copy_strings_kernel(1, &i_arg, bprm);
		if (retval < 0) return retval; 
		bprm->argc++;
	}
	retval = copy_strings_kernel(1, &i_name, bprm);
	if (retval < 0)	return retval;
	bprm->argc++;

	/*
	 * OK, now restart the process with the interpreter's inode.
	 * Note that we use open_exec() as the name is now in kernel
	 * space, and we don't need to copy it.
	 */
	file = open_exec(interp);
	if (IS_ERR(file))
		return PTR_ERR(file);

	bprm->file = file;

	retval = prepare_binprm(bprm);
	if (retval < 0)
		return retval;

	return search_binary_handler(bprm);
}

static struct linux_binfmt em86_format = {
	.module		= THIS_MODULE,
	.load_binary	= load_em86,
};

static int __init init_em86_binfmt(void)
{
	register_binfmt(&em86_format);
	return 0;
}

static void __exit exit_em86_binfmt(void)
{
	unregister_binfmt(&em86_format);
}

core_initcall(init_em86_binfmt);
module_exit(exit_em86_binfmt);
MODULE_LICENSE("GPL");
Commit	Line	Data
	1	/*
	2	* linux/fs/binfmt_em86.c
	3	*
	4	* Based on linux/fs/binfmt_script.c
	5	* Copyright (C) 1996 Martin von Löwis
	6	* original #!-checking implemented by tytso.
	7	*
	8	* em86 changes Copyright (C) 1997 Jim Paradis
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/string.h>
	13	#include <linux/stat.h>
	14	#include <linux/binfmts.h>
	15	#include <linux/elf.h>
	16	#include <linux/init.h>
	17	#include <linux/fs.h>
	18	#include <linux/file.h>
	19	#include <linux/errno.h>
	20
	21
	22	#define EM86_INTERP "/usr/bin/em86"
	23	#define EM86_I_NAME "em86"
	24
	25	static int load_em86(struct linux_binprm *bprm)
	26	{
	27	char interp, i_name, *i_arg;
	28	struct file * file;
	29	int retval;
	30	struct elfhdr elf_ex;
	31
	32	/* Make sure this is a Linux/Intel ELF executable... */
	33	elf_ex = ((struct elfhdr )bprm->buf);
	34
	35	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
	36	return -ENOEXEC;
	37
	38	/* First of all, some simple consistency checks */
	39	if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) \|\|
	40	(!((elf_ex.e_machine == EM_386) \|\| (elf_ex.e_machine == EM_486))) \|\|
	41	!bprm->file->f_op->mmap) {
	42	return -ENOEXEC;
	43	}
	44
	45	allow_write_access(bprm->file);
	46	fput(bprm->file);
	47	bprm->file = NULL;
	48
	49	/* Unlike in the script case, we don't have to do any hairy
	50	* parsing to find our interpreter... it's hardcoded!
	51	*/
	52	interp = EM86_INTERP;
	53	i_name = EM86_I_NAME;
	54	i_arg = NULL; /* We reserve the right to add an arg later */
	55
	56	/*
	57	* Splice in (1) the interpreter's name for argv[0]
	58	* (2) (optional) argument to interpreter
	59	* (3) filename of emulated file (replace argv[0])
	60	*
	61	* This is done in reverse order, because of how the
	62	* user environment and arguments are stored.
	63	*/
	64	remove_arg_zero(bprm);
	65	retval = copy_strings_kernel(1, &bprm->filename, bprm);
	66	if (retval < 0) return retval;
	67	bprm->argc++;
	68	if (i_arg) {
	69	retval = copy_strings_kernel(1, &i_arg, bprm);
	70	if (retval < 0) return retval;
	71	bprm->argc++;
	72	}
	73	retval = copy_strings_kernel(1, &i_name, bprm);
	74	if (retval < 0) return retval;
	75	bprm->argc++;
	76
	77	/*
	78	* OK, now restart the process with the interpreter's inode.
	79	* Note that we use open_exec() as the name is now in kernel
	80	* space, and we don't need to copy it.
	81	*/
	82	file = open_exec(interp);
	83	if (IS_ERR(file))
	84	return PTR_ERR(file);
	85
	86	bprm->file = file;
	87
	88	retval = prepare_binprm(bprm);
	89	if (retval < 0)
	90	return retval;
	91
	92	return search_binary_handler(bprm);
	93	}
	94
	95	static struct linux_binfmt em86_format = {
	96	.module = THIS_MODULE,
	97	.load_binary = load_em86,
	98	};
	99
	100	static int __init init_em86_binfmt(void)
	101	{
	102	register_binfmt(&em86_format);
	103	return 0;
	104	}
	105
	106	static void __exit exit_em86_binfmt(void)
	107	{
	108	unregister_binfmt(&em86_format);
	109	}
	110
	111	core_initcall(init_em86_binfmt);
	112	module_exit(exit_em86_binfmt);
	113	MODULE_LICENSE("GPL");