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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/binfmt_script.c
3 *
Jan Engelhardt96de0e22007-10-19 23:21:04 +02004 * Copyright (C) 1996 Martin von Löwis
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 * original #!-checking implemented by tytso.
6 */
7
8#include <linux/module.h>
9#include <linux/string.h>
10#include <linux/stat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/binfmts.h>
12#include <linux/init.h>
13#include <linux/file.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/err.h>
15#include <linux/fs.h>
16
Al Viro71613c32012-10-20 22:00:48 -040017static int load_script(struct linux_binprm *bprm)
Linus Torvalds1da177e2005-04-16 15:20:36 -070018{
David Howellsd7627462010-08-17 23:52:56 +010019 const char *i_arg, *i_name;
20 char *cp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 struct file *file;
22 char interp[BINPRM_BUF_SIZE];
23 int retval;
24
Kees Cookd7402692012-12-17 16:03:20 -080025 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
Linus Torvalds1da177e2005-04-16 15:20:36 -070026 return -ENOEXEC;
27 /*
28 * This section does the #! interpretation.
29 * Sorta complicated, but hopefully it will work. -TYT
30 */
31
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 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 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -070069 retval = remove_arg_zero(bprm);
70 if (retval)
71 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 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;
Al Viro3c456bf2012-10-20 21:53:31 -040096 return search_binary_handler(bprm);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097}
98
99static struct linux_binfmt script_format = {
100 .module = THIS_MODULE,
101 .load_binary = load_script,
102};
103
104static int __init init_script_binfmt(void)
105{
Al Viro8fc3dc52012-03-17 03:05:16 -0400106 register_binfmt(&script_format);
107 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108}
109
110static void __exit exit_script_binfmt(void)
111{
112 unregister_binfmt(&script_format);
113}
114
115core_initcall(init_script_binfmt);
116module_exit(exit_script_binfmt);
117MODULE_LICENSE("GPL");