1 /* 2 * linux/fs/binfmt_script.c 3 * 4 * Copyright (C) 1996 Martin von Löwis 5 * original #!-checking implemented by tytso. 6 */ 7 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> 15 #include <linux/fs.h> 16 17 static int load_script(struct linux_binprm *bprm) 18 { 19 const char *i_arg, *i_name; 20 char *cp; 21 struct file *file; 22 char interp[BINPRM_BUF_SIZE]; 23 int retval; 24 25 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!')) 26 return -ENOEXEC; 27 /* 28 * This section does the #! interpretation. 29 * Sorta complicated, but hopefully it will work. -TYT 30 */ 31 32 allow_write_access(bprm->file); 33 fput(bprm->file); 34 bprm->file = NULL; 35 36 bprm->buf[BINPRM_BUF_SIZE - 1] = '\0'; 37 if ((cp = strchr(bprm->buf, '\n')) == NULL) 38 cp = bprm->buf+BINPRM_BUF_SIZE-1; 39 *cp = '\0'; 40 while (cp > bprm->buf) { 41 cp--; 42 if ((*cp == ' ') || (*cp == '\t')) 43 *cp = '\0'; 44 else 45 break; 46 } 47 for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++); 48 if (*cp == '\0') 49 return -ENOEXEC; /* No interpreter name found */ 50 i_name = cp; 51 i_arg = NULL; 52 for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++) 53 /* nothing */ ; 54 while ((*cp == ' ') || (*cp == '\t')) 55 *cp++ = '\0'; 56 if (*cp) 57 i_arg = cp; 58 strcpy (interp, i_name); 59 /* 60 * OK, we've parsed out the interpreter name and 61 * (optional) argument. 62 * Splice in (1) the interpreter's name for argv[0] 63 * (2) (optional) argument to interpreter 64 * (3) filename of shell script (replace argv[0]) 65 * 66 * This is done in reverse order, because of how the 67 * user environment and arguments are stored. 68 */ 69 retval = remove_arg_zero(bprm); 70 if (retval) 71 return retval; 72 retval = copy_strings_kernel(1, &bprm->interp, bprm); 73 if (retval < 0) return retval; 74 bprm->argc++; 75 if (i_arg) { 76 retval = copy_strings_kernel(1, &i_arg, bprm); 77 if (retval < 0) return retval; 78 bprm->argc++; 79 } 80 retval = copy_strings_kernel(1, &i_name, bprm); 81 if (retval) return retval; 82 bprm->argc++; 83 retval = bprm_change_interp(interp, bprm); 84 if (retval < 0) 85 return retval; 86 87 /* 88 * OK, now restart the process with the interpreter's dentry. 89 */ 90 file = open_exec(interp); 91 if (IS_ERR(file)) 92 return PTR_ERR(file); 93 94 bprm->file = file; 95 retval = prepare_binprm(bprm); 96 if (retval < 0) 97 return retval; 98 return search_binary_handler(bprm); 99 } 100 101 static struct linux_binfmt script_format = { 102 .module = THIS_MODULE, 103 .load_binary = load_script, 104 }; 105 106 static int __init init_script_binfmt(void) 107 { 108 register_binfmt(&script_format); 109 return 0; 110 } 111 112 static void __exit exit_script_binfmt(void) 113 { 114 unregister_binfmt(&script_format); 115 } 116 117 core_initcall(init_script_binfmt); 118 module_exit(exit_script_binfmt); 119 MODULE_LICENSE("GPL"); 120