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/slab.h> 12 #include <linux/binfmts.h> 13 #include <linux/init.h> 14 #include <linux/file.h> 15 #include <linux/err.h> 16 #include <linux/fs.h> 17 18 static int load_script(struct linux_binprm *bprm,struct pt_regs *regs) 19 { 20 char *cp, *i_name, *i_arg; 21 struct file *file; 22 char interp[BINPRM_BUF_SIZE]; 23 int retval; 24 25 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') || (bprm->sh_bang)) 26 return -ENOEXEC; 27 /* 28 * This section does the #! interpretation. 29 * Sorta complicated, but hopefully it will work. -TYT 30 */ 31 32 bprm->sh_bang = 1; 33 allow_write_access(bprm->file); 34 fput(bprm->file); 35 bprm->file = NULL; 36 37 bprm->buf[BINPRM_BUF_SIZE - 1] = '\0'; 38 if ((cp = strchr(bprm->buf, '\n')) == NULL) 39 cp = bprm->buf+BINPRM_BUF_SIZE-1; 40 *cp = '\0'; 41 while (cp > bprm->buf) { 42 cp--; 43 if ((*cp == ' ') || (*cp == '\t')) 44 *cp = '\0'; 45 else 46 break; 47 } 48 for (cp = bprm->buf+2; (*cp == ' ') || (*cp == '\t'); cp++); 49 if (*cp == '\0') 50 return -ENOEXEC; /* No interpreter name found */ 51 i_name = cp; 52 i_arg = NULL; 53 for ( ; *cp && (*cp != ' ') && (*cp != '\t'); cp++) 54 /* nothing */ ; 55 while ((*cp == ' ') || (*cp == '\t')) 56 *cp++ = '\0'; 57 if (*cp) 58 i_arg = cp; 59 strcpy (interp, i_name); 60 /* 61 * OK, we've parsed out the interpreter name and 62 * (optional) argument. 63 * Splice in (1) the interpreter's name for argv[0] 64 * (2) (optional) argument to interpreter 65 * (3) filename of shell script (replace argv[0]) 66 * 67 * This is done in reverse order, because of how the 68 * user environment and arguments are stored. 69 */ 70 retval = remove_arg_zero(bprm); 71 if (retval) 72 return retval; 73 retval = copy_strings_kernel(1, &bprm->interp, bprm); 74 if (retval < 0) return retval; 75 bprm->argc++; 76 if (i_arg) { 77 retval = copy_strings_kernel(1, &i_arg, bprm); 78 if (retval < 0) return retval; 79 bprm->argc++; 80 } 81 retval = copy_strings_kernel(1, &i_name, bprm); 82 if (retval) return retval; 83 bprm->argc++; 84 bprm->interp = interp; 85 86 /* 87 * OK, now restart the process with the interpreter's dentry. 88 */ 89 file = open_exec(interp); 90 if (IS_ERR(file)) 91 return PTR_ERR(file); 92 93 bprm->file = file; 94 retval = prepare_binprm(bprm); 95 if (retval < 0) 96 return retval; 97 return search_binary_handler(bprm,regs); 98 } 99 100 static struct linux_binfmt script_format = { 101 .module = THIS_MODULE, 102 .load_binary = load_script, 103 }; 104 105 static int __init init_script_binfmt(void) 106 { 107 return register_binfmt(&script_format); 108 } 109 110 static void __exit exit_script_binfmt(void) 111 { 112 unregister_binfmt(&script_format); 113 } 114 115 core_initcall(init_script_binfmt); 116 module_exit(exit_script_binfmt); 117 MODULE_LICENSE("GPL"); 118