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/smp_lock.h> 16 #include <linux/err.h> 17 #include <linux/fs.h> 18 19 static int load_script(struct linux_binprm *bprm,struct pt_regs *regs) 20 { 21 char *cp, *i_name, *i_arg; 22 struct file *file; 23 char interp[BINPRM_BUF_SIZE]; 24 int retval; 25 26 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') || (bprm->sh_bang)) 27 return -ENOEXEC; 28 /* 29 * This section does the #! interpretation. 30 * Sorta complicated, but hopefully it will work. -TYT 31 */ 32 33 bprm->sh_bang++; 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 remove_arg_zero(bprm); 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 bprm->interp = interp; 84 85 /* 86 * OK, now restart the process with the interpreter's dentry. 87 */ 88 file = open_exec(interp); 89 if (IS_ERR(file)) 90 return PTR_ERR(file); 91 92 bprm->file = file; 93 retval = prepare_binprm(bprm); 94 if (retval < 0) 95 return retval; 96 return search_binary_handler(bprm,regs); 97 } 98 99 static struct linux_binfmt script_format = { 100 .module = THIS_MODULE, 101 .load_binary = load_script, 102 }; 103 104 static int __init init_script_binfmt(void) 105 { 106 return register_binfmt(&script_format); 107 } 108 109 static void __exit exit_script_binfmt(void) 110 { 111 unregister_binfmt(&script_format); 112 } 113 114 core_initcall(init_script_binfmt); 115 module_exit(exit_script_binfmt); 116 MODULE_LICENSE("GPL"); 117