[thirdparty/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;

	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
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	allow_write_access(bprm->file);
	52	fput(bprm->file);
	53	bprm->file = NULL;
	54
	55	/* Unlike in the script case, we don't have to do any hairy
	56	* parsing to find our interpreter... it's hardcoded!
	57	*/
	58	interp = EM86_INTERP;
	59	i_name = EM86_I_NAME;
	60	i_arg = NULL; /* We reserve the right to add an arg later */
	61
	62	/*
	63	* Splice in (1) the interpreter's name for argv[0]
	64	* (2) (optional) argument to interpreter
	65	* (3) filename of emulated file (replace argv[0])
	66	*
	67	* This is done in reverse order, because of how the
	68	* user environment and arguments are stored.
	69	*/
	70	remove_arg_zero(bprm);
	71	retval = copy_strings_kernel(1, &bprm->filename, bprm);
	72	if (retval < 0) return retval;
	73	bprm->argc++;
	74	if (i_arg) {
	75	retval = copy_strings_kernel(1, &i_arg, bprm);
	76	if (retval < 0) return retval;
	77	bprm->argc++;
	78	}
	79	retval = copy_strings_kernel(1, &i_name, bprm);
	80	if (retval < 0) return retval;
	81	bprm->argc++;
	82
	83	/*
	84	* OK, now restart the process with the interpreter's inode.
	85	* Note that we use open_exec() as the name is now in kernel
	86	* space, and we don't need to copy it.
	87	*/
	88	file = open_exec(interp);
	89	if (IS_ERR(file))
	90	return PTR_ERR(file);
	91
	92	bprm->file = file;
	93
	94	retval = prepare_binprm(bprm);
	95	if (retval < 0)
	96	return retval;
	97
3c456bfc	98	return search_binary_handler(bprm);
1da177e4 LT	99	}
	100
	101	static struct linux_binfmt em86_format = {
	102	.module = THIS_MODULE,
	103	.load_binary = load_em86,
	104	};
	105
	106	static int __init init_em86_binfmt(void)
	107	{
8fc3dc5a AV	108	register_binfmt(&em86_format);
8fc3dc5a AV	109	return 0;
1da177e4 LT	110	}
	111
	112	static void __exit exit_em86_binfmt(void)
	113	{
	114	unregister_binfmt(&em86_format);
	115	}
	116
	117	core_initcall(init_em86_binfmt);
	118	module_exit(exit_em86_binfmt);
	119	MODULE_LICENSE("GPL");