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;
22 char interp[BINPRM_BUF_SIZE];
25 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
29 * If the script filename will be inaccessible after exec, typically
30 * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give
31 * up now (on the assumption that the interpreter will want to load
34 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
38 * This section does the #! interpretation.
39 * Sorta complicated, but hopefully it will work. -TYT
42 allow_write_access(bprm->file);
46 bprm->buf[BINPRM_BUF_SIZE - 1] = '\0';
47 if ((cp = strchr(bprm->buf, '\n')) == NULL)
48 cp = bprm->buf+BINPRM_BUF_SIZE-1;
50 while (cp > bprm->buf) {
52 if ((*cp == ' ') || (*cp == '\t'))
57 for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++);
59 return -ENOEXEC; /* No interpreter name found */
62 for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++)
64 while ((*cp == ' ') || (*cp == '\t'))
68 strcpy (interp, i_name);
70 * OK, we've parsed out the interpreter name and
71 * (optional) argument.
72 * Splice in (1) the interpreter's name for argv[0]
73 * (2) (optional) argument to interpreter
74 * (3) filename of shell script (replace argv[0])
76 * This is done in reverse order, because of how the
77 * user environment and arguments are stored.
79 retval = remove_arg_zero(bprm);
82 retval = copy_strings_kernel(1, &bprm->interp, bprm);
83 if (retval < 0) return retval;
86 retval = copy_strings_kernel(1, &i_arg, bprm);
87 if (retval < 0) return retval;
90 retval = copy_strings_kernel(1, &i_name, bprm);
91 if (retval) return retval;
93 retval = bprm_change_interp(interp, bprm);
98 * OK, now restart the process with the interpreter's dentry.
100 file = open_exec(interp);
102 return PTR_ERR(file);
105 retval = prepare_binprm(bprm);
108 return search_binary_handler(bprm);
111 static struct linux_binfmt script_format = {
112 .module = THIS_MODULE,
113 .load_binary = load_script,
116 static int __init init_script_binfmt(void)
118 register_binfmt(&script_format);
122 static void __exit exit_script_binfmt(void)
124 unregister_binfmt(&script_format);
127 core_initcall(init_script_binfmt);
128 module_exit(exit_script_binfmt);
129 MODULE_LICENSE("GPL");