/* * 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) { const char *i_arg, *i_name; char *cp; struct file *file; int retval; if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!')) return -ENOEXEC; /* * If the script filename will be inaccessible after exec, typically * because it is a "/dev/fd/<fd>/.." path against an O_CLOEXEC fd, give * up now (on the assumption that the interpreter will want to load * this file). */ if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) return -ENOENT; /* * This section does the #! interpretation. * Sorta complicated, but hopefully it will work. -TYT */ 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; /* * 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++; retval = bprm_change_interp(i_name, bprm); if (retval < 0) return retval; /* * OK, now restart the process with the interpreter's dentry. */ file = open_exec(i_name); 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 script_format = { .module = THIS_MODULE, .load_binary = load_script, }; static int __init init_script_binfmt(void) { register_binfmt(&script_format); return 0; } static void __exit exit_script_binfmt(void) { unregister_binfmt(&script_format); } core_initcall(init_script_binfmt); module_exit(exit_script_binfmt); MODULE_LICENSE("GPL");