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,struct pt_regs *regs) 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 (bprm->recursion_depth > BINPRM_MAX_RECURSION)) 27 return -ENOEXEC; 28 /* 29 * This section does the #! interpretation. 30 * Sorta complicated, but hopefully it will work. -TYT 31 */ 32 33 bprm->recursion_depth++; 34 allow_write_access(bprm->file); 35 fput(bprm->file); 36 bprm->file = NULL; 37 38 bprm->buf[BINPRM_BUF_SIZE - 1] = '\0'; 39 if ((cp = strchr(bprm->buf, '\n')) == NULL) 40 cp = bprm->buf+BINPRM_BUF_SIZE-1; 41 *cp = '\0'; 42 while (cp > bprm->buf) { 43 cp--; 44 if ((*cp == ' ') || (*cp == '\t')) 45 *cp = '\0'; 46 else 47 break; 48 } 49 for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++); 50 if (*cp == '\0') 51 return -ENOEXEC; /* No interpreter name found */ 52 i_name = cp; 53 i_arg = NULL; 54 for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++) 55 /* nothing */ ; 56 while ((*cp == ' ') || (*cp == '\t')) 57 *cp++ = '\0'; 58 if (*cp) 59 i_arg = cp; 60 strcpy (interp, i_name); 61 /* 62 * OK, we've parsed out the interpreter name and 63 * (optional) argument. 64 * Splice in (1) the interpreter's name for argv[0] 65 * (2) (optional) argument to interpreter 66 * (3) filename of shell script (replace argv[0]) 67 * 68 * This is done in reverse order, because of how the 69 * user environment and arguments are stored. 70 */ 71 retval = remove_arg_zero(bprm); 72 if (retval) 73 return retval; 74 retval = copy_strings_kernel(1, &bprm->interp, bprm); 75 if (retval < 0) return retval; 76 bprm->argc++; 77 if (i_arg) { 78 retval = copy_strings_kernel(1, &i_arg, bprm); 79 if (retval < 0) return retval; 80 bprm->argc++; 81 } 82 retval = copy_strings_kernel(1, &i_name, bprm); 83 if (retval) return retval; 84 bprm->argc++; 85 bprm->interp = interp; 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,regs); 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 return register_binfmt(&script_format); 109 } 110 111 static void __exit exit_script_binfmt(void) 112 { 113 unregister_binfmt(&script_format); 114 } 115 116 core_initcall(init_script_binfmt); 117 module_exit(exit_script_binfmt); 118 MODULE_LICENSE("GPL"); 119