[linux.git] / fs / binfmt_script.c

/*
 *  linux/fs/binfmt_script.c
 *
 *  Copyright (C) 1996  Martin von Löwis
 *  original #!-checking implemented by tytso.
 */

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

static int load_script(struct linux_binprm *bprm,struct pt_regs *regs)
{
	char *cp, *i_name, *i_arg;
	struct file *file;
	char interp[BINPRM_BUF_SIZE];
	int retval;

	if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') ||
	    (bprm->recursion_depth > BINPRM_MAX_RECURSION))
		return -ENOEXEC;
	/*
	 * This section does the #! interpretation.
	 * Sorta complicated, but hopefully it will work.  -TYT
	 */

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

	bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
	if ((cp = strchr(bprm->buf, '\n')) == NULL)
		cp = bprm->buf+BINPRM_BUF_SIZE-1;
	*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 == '\0') 
		return -ENOEXEC; /* No interpreter name found */
	i_name = cp;
	i_arg = NULL;
	for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
		/* nothing */ ;
	while ((*cp == ' ') || (*cp == '\t'))
		*cp++ = '\0';
	if (*cp)
		i_arg = cp;
	strcpy (interp, i_name);
	/*
	 * OK, we've parsed out the interpreter name and
	 * (optional) argument.
	 * Splice in (1) the interpreter's name for argv[0]
	 *           (2) (optional) argument to interpreter
	 *           (3) filename of shell script (replace argv[0])
	 *
	 * This is done in reverse order, because of how the
	 * user environment and arguments are stored.
	 */
	retval = remove_arg_zero(bprm);
	if (retval)
		return retval;
	retval = copy_strings_kernel(1, &bprm->interp, 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) return retval; 
	bprm->argc++;
	bprm->interp = interp;

	/*
	 * OK, now restart the process with the interpreter's dentry.
	 */
	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,regs);
}

static struct linux_binfmt script_format = {
	.module		= THIS_MODULE,
	.load_binary	= load_script,
};

static int __init init_script_binfmt(void)
{
	return register_binfmt(&script_format);
}

static void __exit exit_script_binfmt(void)
{
	unregister_binfmt(&script_format);
}

core_initcall(init_script_binfmt);
module_exit(exit_script_binfmt);
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/binfmt_script.c
	3	*
96de0e25	4	* Copyright (C) 1996 Martin von Löwis
1da177e4 LT	5	* original #!-checking implemented by tytso.
	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/string.h>
	10	#include <linux/stat.h>
1da177e4 LT	11	#include <linux/binfmts.h>
	12	#include <linux/init.h>
	13	#include <linux/file.h>
1da177e4 LT	14	#include <linux/err.h>
	15	#include <linux/fs.h>
	16
	17	static int load_script(struct linux_binprm bprm,struct pt_regs regs)
	18	{
	19	char cp, i_name, *i_arg;
	20	struct file *file;
	21	char interp[BINPRM_BUF_SIZE];
	22	int retval;
	23
bf2a9a39 KS	24	if ((bprm->buf[0] != '#') \|\| (bprm->buf[1] != '!') \|\|
bf2a9a39 KS	25	(bprm->recursion_depth > BINPRM_MAX_RECURSION))
1da177e4 LT	26	return -ENOEXEC;
	27	/*
	28	* This section does the #! interpretation.
	29	* Sorta complicated, but hopefully it will work. -TYT
	30	*/
	31
bf2a9a39	32	bprm->recursion_depth++;
1da177e4 LT	33	allow_write_access(bprm->file);
	34	fput(bprm->file);
	35	bprm->file = NULL;
	36
	37	bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
	38	if ((cp = strchr(bprm->buf, '\n')) == NULL)
	39	cp = bprm->buf+BINPRM_BUF_SIZE-1;
	40	*cp = '\0';
	41	while (cp > bprm->buf) {
	42	cp--;
	43	if ((cp == ' ') \|\| (cp == '\t'))
	44	*cp = '\0';
	45	else
	46	break;
	47	}
	48	for (cp = bprm->buf+2; (cp == ' ') \|\| (cp == '\t'); cp++);
	49	if (*cp == '\0')
	50	return -ENOEXEC; /* No interpreter name found */
	51	i_name = cp;
	52	i_arg = NULL;
	53	for ( ; cp && (cp != ' ') && (*cp != '\t'); cp++)
	54	/* nothing */ ;
	55	while ((cp == ' ') \|\| (cp == '\t'))
	56	*cp++ = '\0';
	57	if (*cp)
	58	i_arg = cp;
	59	strcpy (interp, i_name);
	60	/*
	61	* OK, we've parsed out the interpreter name and
	62	* (optional) argument.
	63	* Splice in (1) the interpreter's name for argv[0]
	64	* (2) (optional) argument to interpreter
	65	* (3) filename of shell script (replace argv[0])
	66	*
	67	* This is done in reverse order, because of how the
	68	* user environment and arguments are stored.
	69	*/
b6a2fea3 OW	70	retval = remove_arg_zero(bprm);
	71	if (retval)
	72	return retval;
1da177e4 LT	73	retval = copy_strings_kernel(1, &bprm->interp, bprm);
	74	if (retval < 0) return retval;
	75	bprm->argc++;
	76	if (i_arg) {
	77	retval = copy_strings_kernel(1, &i_arg, bprm);
	78	if (retval < 0) return retval;
	79	bprm->argc++;
	80	}
	81	retval = copy_strings_kernel(1, &i_name, bprm);
	82	if (retval) return retval;
	83	bprm->argc++;
	84	bprm->interp = interp;
	85
	86	/*
	87	* OK, now restart the process with the interpreter's dentry.
	88	*/
	89	file = open_exec(interp);
	90	if (IS_ERR(file))
	91	return PTR_ERR(file);
	92
	93	bprm->file = file;
	94	retval = prepare_binprm(bprm);
	95	if (retval < 0)
	96	return retval;
	97	return search_binary_handler(bprm,regs);
	98	}
	99
	100	static struct linux_binfmt script_format = {
	101	.module = THIS_MODULE,
	102	.load_binary = load_script,
	103	};
	104
	105	static int __init init_script_binfmt(void)
	106	{
	107	return register_binfmt(&script_format);
	108	}
	109
	110	static void __exit exit_script_binfmt(void)
	111	{
	112	unregister_binfmt(&script_format);
	113	}
	114
	115	core_initcall(init_script_binfmt);
	116	module_exit(exit_script_binfmt);
	117	MODULE_LICENSE("GPL");