1 /* 2 * linux/fs/binfmt_script.c 3 * 4 * Copyright (C) 1996 Martin von L�wis 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++; 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 remove_arg_zero(bprm); 71 retval = copy_strings_kernel(1, &bprm->interp, bprm); 72 if (retval < 0) return retval; 73 bprm->argc++; 74 if (i_arg) { 75 retval = copy_strings_kernel(1, &i_arg, bprm); 76 if (retval < 0) return retval; 77 bprm->argc++; 78 } 79 retval = copy_strings_kernel(1, &i_name, bprm); 80 if (retval) return retval; 81 bprm->argc++; 82 bprm->interp = interp; 83 84 /* 85 * OK, now restart the process with the interpreter's dentry. 86 */ 87 file = open_exec(interp); 88 if (IS_ERR(file)) 89 return PTR_ERR(file); 90 91 bprm->file = file; 92 retval = prepare_binprm(bprm); 93 if (retval < 0) 94 return retval; 95 return search_binary_handler(bprm,regs); 96 } 97 98 static struct linux_binfmt script_format = { 99 .module = THIS_MODULE, 100 .load_binary = load_script, 101 }; 102 103 static int __init init_script_binfmt(void) 104 { 105 return register_binfmt(&script_format); 106 } 107 108 static void __exit exit_script_binfmt(void) 109 { 110 unregister_binfmt(&script_format); 111 } 112 113 core_initcall(init_script_binfmt); 114 module_exit(exit_script_binfmt); 115 MODULE_LICENSE("GPL"); 116