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/malloc.h>
12 #include <linux/binfmts.h>
13 #include <linux/init.h>
14 #include <linux/file.h>
15 #include <linux/smp_lock.h>
16
17 static int load_script(struct linux_binprm *bprm,struct pt_regs *regs)
18 {
19 char *cp, *i_name, *i_arg;
20 struct file *file;
21 char interp[BINPRM_BUF_SIZE];
22 int retval;
23
24 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!') || (bprm->sh_bang))
25 return -ENOEXEC;
26 /*
27 * This section does the #! interpretation.
28 * Sorta complicated, but hopefully it will work. -TYT
29 */
30
31 bprm->sh_bang++;
32 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 = 0;
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 */
69 remove_arg_zero(bprm);
70 retval = copy_strings_kernel(1, &bprm->filename, bprm);
71 if (retval < 0) return retval;
72 bprm->argc++;
73 if (i_arg) {
74 retval = copy_strings_kernel(1, &i_arg, bprm);
75 if (retval < 0) return retval;
76 bprm->argc++;
77 }
78 retval = copy_strings_kernel(1, &i_name, bprm);
79 if (retval) return retval;
80 bprm->argc++;
81 /*
82 * OK, now restart the process with the interpreter's dentry.
83 */
84 file = open_exec(interp);
85 if (IS_ERR(file))
86 return PTR_ERR(file);
87
88 bprm->file = file;
89 retval = prepare_binprm(bprm);
90 if (retval < 0)
91 return retval;
92 return search_binary_handler(bprm,regs);
93 }
94
95 struct linux_binfmt script_format = {
96 NULL, THIS_MODULE, load_script, NULL, NULL, 0
97 };
98
99 static int __init init_script_binfmt(void)
100 {
101 return register_binfmt(&script_format);
102 }
103
104 static void __exit exit_script_binfmt(void)
105 {
106 unregister_binfmt(&script_format);
107 }
108
109 module_init(init_script_binfmt)
110 module_exit(exit_script_binfmt)
111
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