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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/fs/binfmt_em86.c | |
4 | * | |
5 | * Based on linux/fs/binfmt_script.c | |
96de0e25 | 6 | * Copyright (C) 1996 Martin von Löwis |
1da177e4 LT |
7 | * original #!-checking implemented by tytso. |
8 | * | |
9 | * em86 changes Copyright (C) 1997 Jim Paradis | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/string.h> | |
14 | #include <linux/stat.h> | |
1da177e4 LT |
15 | #include <linux/binfmts.h> |
16 | #include <linux/elf.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/fs.h> | |
19 | #include <linux/file.h> | |
20 | #include <linux/errno.h> | |
21 | ||
22 | ||
23 | #define EM86_INTERP "/usr/bin/em86" | |
24 | #define EM86_I_NAME "em86" | |
25 | ||
71613c3b | 26 | static int load_em86(struct linux_binprm *bprm) |
1da177e4 | 27 | { |
a310dcb7 DW |
28 | const char *i_name, *i_arg; |
29 | char *interp; | |
1da177e4 LT |
30 | struct file * file; |
31 | int retval; | |
32 | struct elfhdr elf_ex; | |
33 | ||
34 | /* Make sure this is a Linux/Intel ELF executable... */ | |
35 | elf_ex = *((struct elfhdr *)bprm->buf); | |
36 | ||
37 | if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0) | |
38 | return -ENOEXEC; | |
39 | ||
40 | /* First of all, some simple consistency checks */ | |
41 | if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) || | |
42 | (!((elf_ex.e_machine == EM_386) || (elf_ex.e_machine == EM_486))) || | |
72c2d531 | 43 | !bprm->file->f_op->mmap) { |
1da177e4 LT |
44 | return -ENOEXEC; |
45 | } | |
46 | ||
51f39a1f DD |
47 | /* Need to be able to load the file after exec */ |
48 | if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) | |
49 | return -ENOENT; | |
50 | ||
1da177e4 LT |
51 | allow_write_access(bprm->file); |
52 | fput(bprm->file); | |
53 | bprm->file = NULL; | |
54 | ||
55 | /* Unlike in the script case, we don't have to do any hairy | |
56 | * parsing to find our interpreter... it's hardcoded! | |
57 | */ | |
58 | interp = EM86_INTERP; | |
59 | i_name = EM86_I_NAME; | |
60 | i_arg = NULL; /* We reserve the right to add an arg later */ | |
61 | ||
62 | /* | |
63 | * Splice in (1) the interpreter's name for argv[0] | |
64 | * (2) (optional) argument to interpreter | |
65 | * (3) filename of emulated file (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->filename, 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 < 0) return retval; | |
81 | bprm->argc++; | |
82 | ||
83 | /* | |
84 | * OK, now restart the process with the interpreter's inode. | |
85 | * Note that we use open_exec() as the name is now in kernel | |
86 | * space, and we don't need to copy it. | |
87 | */ | |
88 | file = open_exec(interp); | |
89 | if (IS_ERR(file)) | |
90 | return PTR_ERR(file); | |
91 | ||
92 | bprm->file = file; | |
93 | ||
94 | retval = prepare_binprm(bprm); | |
95 | if (retval < 0) | |
96 | return retval; | |
97 | ||
3c456bfc | 98 | return search_binary_handler(bprm); |
1da177e4 LT |
99 | } |
100 | ||
101 | static struct linux_binfmt em86_format = { | |
102 | .module = THIS_MODULE, | |
103 | .load_binary = load_em86, | |
104 | }; | |
105 | ||
106 | static int __init init_em86_binfmt(void) | |
107 | { | |
8fc3dc5a AV |
108 | register_binfmt(&em86_format); |
109 | return 0; | |
1da177e4 LT |
110 | } |
111 | ||
112 | static void __exit exit_em86_binfmt(void) | |
113 | { | |
114 | unregister_binfmt(&em86_format); | |
115 | } | |
116 | ||
117 | core_initcall(init_em86_binfmt); | |
118 | module_exit(exit_em86_binfmt); | |
119 | MODULE_LICENSE("GPL"); |