2 * linux/fs/binfmt_script.c
4 * Copyright (C) 1996 Martin von Löwis
5 * original #!-checking implemented by tytso.
8 #include <linux/module.h>
9 #include <linux/string.h>
10 #include <linux/stat.h>
11 #include <linux/binfmts.h>
12 #include <linux/init.h>
13 #include <linux/file.h>
14 #include <linux/err.h>
17 static int load_script(struct linux_binprm *bprm)
19 const char *i_arg, *i_name;
24 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
28 * If the script filename will be inaccessible after exec, typically
29 * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
30 * up now (on the assumption that the interpreter will want to load
33 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
37 * This section does the #! interpretation.
38 * Sorta complicated, but hopefully it will work. -TYT
41 allow_write_access(bprm->file);
45 for (cp = bprm->buf+2;; cp++) {
46 if (cp >= bprm->buf + BINPRM_BUF_SIZE)
48 if (!*cp || (*cp == '\n'))
53 while (cp > bprm->buf) {
55 if ((*cp == ' ') || (*cp == '\t'))
60 for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
62 return -ENOEXEC; /* No interpreter name found */
65 for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
67 while ((*cp == ' ') || (*cp == '\t'))
72 * OK, we've parsed out the interpreter name and
73 * (optional) argument.
74 * Splice in (1) the interpreter's name for argv[0]
75 * (2) (optional) argument to interpreter
76 * (3) filename of shell script (replace argv[0])
78 * This is done in reverse order, because of how the
79 * user environment and arguments are stored.
81 retval = remove_arg_zero(bprm);
84 retval = copy_strings_kernel(1, &bprm->interp, bprm);
89 retval = copy_strings_kernel(1, &i_arg, bprm);
94 retval = copy_strings_kernel(1, &i_name, bprm);
98 retval = bprm_change_interp(i_name, bprm);
103 * OK, now restart the process with the interpreter's dentry.
105 file = open_exec(i_name);
107 return PTR_ERR(file);
110 retval = prepare_binprm(bprm);
113 return search_binary_handler(bprm);
116 static struct linux_binfmt script_format = {
117 .module = THIS_MODULE,
118 .load_binary = load_script,
121 static int __init init_script_binfmt(void)
123 register_binfmt(&script_format);
127 static void __exit exit_script_binfmt(void)
129 unregister_binfmt(&script_format);
132 core_initcall(init_script_binfmt);
133 module_exit(exit_script_binfmt);
134 MODULE_LICENSE("GPL");