[linux.git] / fs / binfmt_em86.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  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)
{
	const char *i_name, *i_arg;
	char *interp;
	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;
	}

	/* Need to be able to load the file after exec */
	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
		return -ENOENT;

	/* 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_string_kernel(bprm->filename, bprm);
	if (retval < 0) return retval; 
	bprm->argc++;
	if (i_arg) {
		retval = copy_string_kernel(i_arg, bprm);
		if (retval < 0) return retval; 
		bprm->argc++;
	}
	retval = copy_string_kernel(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->interpreter = file;
	return 0;
}

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
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	/*
	3	* linux/fs/binfmt_em86.c
	4	*
	5	* Based on linux/fs/binfmt_script.c
96de0e25	6	* Copyright (C) 1996 Martin von Löwis
1da177e4 LT	7	* original #!-checking implemented by tytso.
	8	*
	9	* em86 changes Copyright (C) 1997 Jim Paradis
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/string.h>
	14	#include <linux/stat.h>
1da177e4 LT	15	#include <linux/binfmts.h>
	16	#include <linux/elf.h>
	17	#include <linux/init.h>
	18	#include <linux/fs.h>
	19	#include <linux/file.h>
	20	#include <linux/errno.h>
	21
	22
	23	#define EM86_INTERP "/usr/bin/em86"
	24	#define EM86_I_NAME "em86"
	25
71613c3b	26	static int load_em86(struct linux_binprm *bprm)
1da177e4	27	{
a310dcb7 DW	28	const char i_name, i_arg;
a310dcb7 DW	29	char *interp;
1da177e4 LT	30	struct file * file;
	31	int retval;
	32	struct elfhdr elf_ex;
	33
	34	/* Make sure this is a Linux/Intel ELF executable... */
	35	elf_ex = ((struct elfhdr )bprm->buf);
	36
	37	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
	38	return -ENOEXEC;
	39
	40	/* First of all, some simple consistency checks */
	41	if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) \|\|
	42	(!((elf_ex.e_machine == EM_386) \|\| (elf_ex.e_machine == EM_486))) \|\|
72c2d531	43	!bprm->file->f_op->mmap) {
1da177e4 LT	44	return -ENOEXEC;
	45	}
	46
51f39a1f DD	47	/* Need to be able to load the file after exec */
	48	if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
	49	return -ENOENT;
	50
1da177e4 LT	51	/* Unlike in the script case, we don't have to do any hairy
	52	* parsing to find our interpreter... it's hardcoded!
	53	*/
	54	interp = EM86_INTERP;
	55	i_name = EM86_I_NAME;
	56	i_arg = NULL; /* We reserve the right to add an arg later */
	57
	58	/*
	59	* Splice in (1) the interpreter's name for argv[0]
	60	* (2) (optional) argument to interpreter
	61	* (3) filename of emulated file (replace argv[0])
	62	*
	63	* This is done in reverse order, because of how the
	64	* user environment and arguments are stored.
	65	*/
	66	remove_arg_zero(bprm);
986db2d1	67	retval = copy_string_kernel(bprm->filename, bprm);
1da177e4 LT	68	if (retval < 0) return retval;
	69	bprm->argc++;
	70	if (i_arg) {
986db2d1	71	retval = copy_string_kernel(i_arg, bprm);
1da177e4 LT	72	if (retval < 0) return retval;
	73	bprm->argc++;
	74	}
986db2d1	75	retval = copy_string_kernel(i_name, bprm);
1da177e4 LT	76	if (retval < 0) return retval;
	77	bprm->argc++;
	78
	79	/*
	80	* OK, now restart the process with the interpreter's inode.
	81	* Note that we use open_exec() as the name is now in kernel
	82	* space, and we don't need to copy it.
	83	*/
	84	file = open_exec(interp);
	85	if (IS_ERR(file))
	86	return PTR_ERR(file);
	87
bc2bf338 EB	88	bprm->interpreter = file;
bc2bf338 EB	89	return 0;
1da177e4 LT	90	}
	91
	92	static struct linux_binfmt em86_format = {
	93	.module = THIS_MODULE,
	94	.load_binary = load_em86,
	95	};
	96
	97	static int __init init_em86_binfmt(void)
	98	{
8fc3dc5a AV	99	register_binfmt(&em86_format);
8fc3dc5a AV	100	return 0;
1da177e4 LT	101	}
	102
	103	static void __exit exit_em86_binfmt(void)
	104	{
	105	unregister_binfmt(&em86_format);
	106	}
	107
	108	core_initcall(init_em86_binfmt);
	109	module_exit(exit_em86_binfmt);
	110	MODULE_LICENSE("GPL");