Mercurial > crates > nonstick
annotate src/module.rs @ 12:30831c70e5c0
Remove PhantomData usage.
PhantomData is used through the library to substitute associated
constants (to types). However, calling
`PamItem::item_type(PhantomData<T>)` can easily be substituted by
calling `T::item_type()`, getting rid of the need for PhantomData.
author | Marc Brinkmann <git@marcbrinkmann.de> |
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date | Sun, 26 Feb 2017 12:12:36 +0100 |
parents | 74b53b921b23 |
children | cc39d168aeb8 |
rev | line source |
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1 | 1 //! Functions for use in pam modules. |
2 | |
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3 use libc::c_char; |
1 | 4 use std::{mem, ptr}; |
5 use std::ffi::{CStr, CString}; | |
6 | |
7 use constants; | |
8 use constants::*; | |
9 | |
10 /// Opaque type, used as a pointer when making pam API calls. | |
11 /// | |
12 /// A module is invoked via an external function such as `pam_sm_authenticate`. | |
13 /// Such a call provides a pam handle pointer. The same pointer should be given | |
14 /// as an argument when making API calls. | |
15 #[allow(missing_copy_implementations)] | |
16 pub enum PamHandleT {} | |
17 | |
18 #[allow(missing_copy_implementations)] | |
19 enum PamItemT {} | |
20 | |
21 #[allow(missing_copy_implementations)] | |
22 pub enum PamDataT {} | |
23 | |
24 #[link(name = "pam")] | |
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25 extern "C" { |
1 | 26 fn pam_get_data(pamh: *const PamHandleT, |
27 module_data_name: *const c_char, | |
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28 data: &mut *const PamDataT) |
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29 -> PamResultCode; |
1 | 30 |
31 fn pam_set_data(pamh: *const PamHandleT, | |
32 module_data_name: *const c_char, | |
33 data: Box<PamDataT>, | |
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34 cleanup: extern "C" fn(pamh: *const PamHandleT, |
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35 data: Box<PamDataT>, |
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36 error_status: PamResultCode)) |
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37 -> PamResultCode; |
1 | 38 |
39 fn pam_get_item(pamh: *const PamHandleT, | |
40 item_type: PamItemType, | |
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41 item: &mut *const PamItemT) |
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42 -> PamResultCode; |
1 | 43 |
44 fn pam_set_item(pamh: *mut PamHandleT, | |
45 item_type: PamItemType, | |
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46 item: &PamItemT) |
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47 -> PamResultCode; |
1 | 48 |
49 fn pam_get_user(pamh: *const PamHandleT, | |
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50 user: &*mut c_char, |
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51 prompt: *const c_char) |
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52 -> PamResultCode; |
1 | 53 } |
54 | |
55 pub type PamResult<T> = Result<T, PamResultCode>; | |
56 | |
57 /// Type-level mapping for safely retrieving values with `get_item`. | |
58 /// | |
59 /// See `pam_get_item` in | |
60 /// http://www.linux-pam.org/Linux-PAM-html/mwg-expected-by-module-item.html | |
61 pub trait PamItem { | |
62 /// Maps a Rust type to a pam constant. | |
63 /// | |
64 /// For example, the type PamConv maps to the constant PAM_CONV. The pam | |
65 /// API contract specifies that when the API function `pam_get_item` is | |
66 /// called with the constant PAM_CONV, it will return a value of type | |
67 /// `PamConv`. | |
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68 fn item_type() -> PamItemType; |
1 | 69 } |
70 | |
71 /// Gets some value, identified by `key`, that has been set by the module | |
72 /// previously. | |
73 /// | |
74 /// See `pam_get_data` in | |
75 /// http://www.linux-pam.org/Linux-PAM-html/mwg-expected-by-module-item.html | |
76 pub unsafe fn get_data<'a, T>(pamh: &'a PamHandleT, key: &str) -> PamResult<&'a T> { | |
77 let c_key = CString::new(key).unwrap().as_ptr(); | |
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78 let mut ptr: *const PamDataT = ptr::null(); |
1 | 79 let res = pam_get_data(pamh, c_key, &mut ptr); |
80 if constants::PAM_SUCCESS == res && !ptr.is_null() { | |
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81 let typed_ptr: *const T = mem::transmute(ptr); |
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82 let data: &T = &*typed_ptr; |
1 | 83 Ok(data) |
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84 } else { |
1 | 85 Err(res) |
86 } | |
87 } | |
88 | |
89 /// Stores a value that can be retrieved later with `get_data`. The value lives | |
90 /// as long as the current pam cycle. | |
91 /// | |
92 /// See `pam_set_data` in | |
93 /// http://www.linux-pam.org/Linux-PAM-html/mwg-expected-by-module-item.html | |
94 pub fn set_data<T>(pamh: &PamHandleT, key: &str, data: Box<T>) -> PamResult<()> { | |
95 let c_key = CString::new(key).unwrap().as_ptr(); | |
96 let res = unsafe { | |
97 let c_data: Box<PamDataT> = mem::transmute(data); | |
98 pam_set_data(pamh, c_key, c_data, cleanup::<T>) | |
99 }; | |
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100 if constants::PAM_SUCCESS == res { |
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101 Ok(()) |
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102 } else { |
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103 Err(res) |
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104 } |
1 | 105 } |
106 | |
107 #[no_mangle] | |
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108 pub extern "C" fn cleanup<T>(_: *const PamHandleT, c_data: Box<PamDataT>, _: PamResultCode) { |
1 | 109 unsafe { |
110 let data: Box<T> = mem::transmute(c_data); | |
111 mem::drop(data); | |
112 } | |
113 } | |
114 | |
115 /// Retrieves a value that has been set, possibly by the pam client. This is | |
116 /// particularly useful for getting a `PamConv` reference. | |
117 /// | |
118 /// See `pam_get_item` in | |
119 /// http://www.linux-pam.org/Linux-PAM-html/mwg-expected-by-module-item.html | |
120 pub fn get_item<'a, T: PamItem>(pamh: &'a PamHandleT) -> PamResult<&'a T> { | |
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121 let mut ptr: *const PamItemT = ptr::null(); |
1 | 122 let (res, item) = unsafe { |
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123 let r = pam_get_item(pamh, T::item_type(), &mut ptr); |
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124 let typed_ptr: *const T = mem::transmute(ptr); |
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125 let t: &T = &*typed_ptr; |
1 | 126 (r, t) |
127 }; | |
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128 if constants::PAM_SUCCESS == res { |
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129 Ok(item) |
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130 } else { |
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131 Err(res) |
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132 } |
1 | 133 } |
134 | |
10 | 135 /// Sets a value in the pam context. The value can be retrieved using |
136 /// `get_item`. | |
137 /// | |
138 /// Note that all items are strings, except `PAM_CONV` and `PAM_FAIL_DELAY`. | |
139 /// | |
140 /// See `pam_set_item` in | |
141 /// http://www.linux-pam.org/Linux-PAM-html/mwg-expected-by-module-item.html | |
142 pub fn set_item_str<'a, P: PamItem>(pamh: &'a mut PamHandleT, item: &str) -> PamResult<()> { | |
143 let c_item = CString::new(item).unwrap().as_ptr(); | |
144 | |
145 let res = unsafe { | |
146 pam_set_item(pamh, | |
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30831c70e5c0
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147 P::item_type(), |
10 | 148 |
149 // unwrapping is okay here, as c_item will not be a NULL | |
150 // pointer | |
151 (c_item as *const PamItemT).as_ref().unwrap()) | |
152 }; | |
153 if constants::PAM_SUCCESS == res { | |
154 Ok(()) | |
155 } else { | |
156 Err(res) | |
157 } | |
158 } | |
159 | |
1 | 160 /// Retrieves the name of the user who is authenticating or logging in. |
161 /// | |
162 /// This is really a specialization of `get_item`. | |
163 /// | |
164 /// See `pam_get_user` in | |
165 /// http://www.linux-pam.org/Linux-PAM-html/mwg-expected-by-module-item.html | |
166 pub fn get_user<'a>(pamh: &'a PamHandleT, prompt: Option<&str>) -> PamResult<String> { | |
167 let ptr: *mut c_char = ptr::null_mut(); | |
168 let c_prompt = match prompt { | |
169 Some(p) => CString::new(p).unwrap().as_ptr(), | |
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170 None => ptr::null(), |
1 | 171 }; |
172 let res = unsafe { pam_get_user(pamh, &ptr, c_prompt) }; | |
173 if constants::PAM_SUCCESS == res && !ptr.is_null() { | |
174 let const_ptr = ptr as *const c_char; | |
175 let bytes = unsafe { CStr::from_ptr(const_ptr).to_bytes() }; | |
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176 String::from_utf8(bytes.to_vec()).map_err(|_| PAM_CONV_ERR) |
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177 } else { |
1 | 178 Err(res) |
179 } | |
180 } |