/src/botan/build/include/botan/internal/os_utils.h
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1 | | /* |
2 | | * OS specific utility functions |
3 | | * (C) 2015,2016,2017,2018 Jack Lloyd |
4 | | * |
5 | | * Botan is released under the Simplified BSD License (see license.txt) |
6 | | */ |
7 | | |
8 | | #ifndef BOTAN_OS_UTILS_H_ |
9 | | #define BOTAN_OS_UTILS_H_ |
10 | | |
11 | | #include <botan/types.h> |
12 | | #include <functional> |
13 | | #include <string> |
14 | | #include <vector> |
15 | | |
16 | | namespace Botan { |
17 | | |
18 | | namespace OS { |
19 | | |
20 | | /* |
21 | | * This header is internal (not installed) and these functions are not |
22 | | * intended to be called by applications. However they are given public |
23 | | * visibility (using BOTAN_TEST_API macro) for the tests. This also probably |
24 | | * allows them to be overridden by the application on ELF systems, but |
25 | | * this hasn't been tested. |
26 | | */ |
27 | | |
28 | | /** |
29 | | * @return process ID assigned by the operating system. |
30 | | * On Unix and Windows systems, this always returns a result |
31 | | * On IncludeOS it returns 0 since there is no process ID to speak of |
32 | | * in a unikernel. |
33 | | */ |
34 | | uint32_t BOTAN_TEST_API get_process_id(); |
35 | | |
36 | | /** |
37 | | * Test if we are currently running with elevated permissions |
38 | | * eg setuid, setgid, or with POSIX caps set. |
39 | | */ |
40 | | bool running_in_privileged_state(); |
41 | | |
42 | | /** |
43 | | * @return CPU processor clock, if available |
44 | | * |
45 | | * On Windows, calls QueryPerformanceCounter. |
46 | | * |
47 | | * Under GCC or Clang on supported platforms the hardware cycle counter is queried. |
48 | | * Currently supported processors are x86, PPC, Alpha, SPARC, IA-64, S/390x, and HP-PA. |
49 | | * If no CPU cycle counter is available on this system, returns zero. |
50 | | */ |
51 | | uint64_t BOTAN_TEST_API get_cpu_cycle_counter(); |
52 | | |
53 | | size_t BOTAN_TEST_API get_cpu_total(); |
54 | | size_t BOTAN_TEST_API get_cpu_available(); |
55 | | |
56 | | /** |
57 | | * Return the ELF auxiliary vector cooresponding to the given ID. |
58 | | * This only makes sense on Unix-like systems and is currently |
59 | | * only supported on Linux, Android, and FreeBSD. |
60 | | * |
61 | | * Returns zero if not supported on the current system or if |
62 | | * the id provided is not known. |
63 | | */ |
64 | | unsigned long get_auxval(unsigned long id); |
65 | | |
66 | | /* |
67 | | * @return best resolution timestamp available |
68 | | * |
69 | | * The epoch and update rate of this clock is arbitrary and depending |
70 | | * on the hardware it may not tick at a constant rate. |
71 | | * |
72 | | * Uses hardware cycle counter, if available. |
73 | | * On POSIX platforms clock_gettime is used with a monotonic timer |
74 | | * As a final fallback std::chrono::high_resolution_clock is used. |
75 | | */ |
76 | | uint64_t BOTAN_TEST_API get_high_resolution_clock(); |
77 | | |
78 | | /** |
79 | | * @return system clock (reflecting wall clock) with best resolution |
80 | | * available, normalized to nanoseconds resolution. |
81 | | */ |
82 | | uint64_t BOTAN_TEST_API get_system_timestamp_ns(); |
83 | | |
84 | | /** |
85 | | * @return maximum amount of memory (in bytes) Botan could/should |
86 | | * hyptothetically allocate for the memory poool. Reads environment |
87 | | * variable "BOTAN_MLOCK_POOL_SIZE", set to "0" to disable pool. |
88 | | */ |
89 | | size_t get_memory_locking_limit(); |
90 | | |
91 | | /** |
92 | | * Return the size of a memory page, if that can be derived on the |
93 | | * current system. Otherwise returns some default value (eg 4096) |
94 | | */ |
95 | | size_t system_page_size(); |
96 | | |
97 | | /** |
98 | | * Return the cache line size of the current processor using some |
99 | | * OS specific interface, or 0 if not available on this platform. |
100 | | */ |
101 | | size_t get_cache_line_size(); |
102 | | |
103 | | /** |
104 | | * Read the value of an environment variable, setting it to value_out if it |
105 | | * exists. Returns false and sets value_out to empty string if no such variable |
106 | | * is set. If the process seems to be running in a privileged state (such as |
107 | | * setuid) then always returns false and does not examine the environment. |
108 | | */ |
109 | | bool read_env_variable(std::string& value_out, const std::string& var_name); |
110 | | |
111 | | /** |
112 | | * Read the value of an environment variable and convert it to an |
113 | | * integer. If not set or conversion fails, returns the default value. |
114 | | * |
115 | | * If the process seems to be running in a privileged state (such as setuid) |
116 | | * then always returns nullptr, similiar to glibc's secure_getenv. |
117 | | */ |
118 | | size_t read_env_variable_sz(const std::string& var_name, size_t def_value = 0); |
119 | | |
120 | | /** |
121 | | * Request count pages of RAM which are locked into memory using mlock, |
122 | | * VirtualLock, or some similar OS specific API. Free it with free_locked_pages. |
123 | | * |
124 | | * Returns an empty list on failure. This function is allowed to return fewer |
125 | | * than count pages. |
126 | | * |
127 | | * The contents of the allocated pages are undefined. |
128 | | * |
129 | | * Each page is preceded by and followed by a page which is marked |
130 | | * as noaccess, such that accessing it will cause a crash. This turns |
131 | | * out of bound reads/writes into crash events. |
132 | | * |
133 | | * @param count requested number of locked pages |
134 | | */ |
135 | | std::vector<void*> allocate_locked_pages(size_t count); |
136 | | |
137 | | /** |
138 | | * Free memory allocated by allocate_locked_pages |
139 | | * @param pages a list of pages returned by allocate_locked_pages |
140 | | */ |
141 | | void free_locked_pages(const std::vector<void*>& pages); |
142 | | |
143 | | /** |
144 | | * Set the MMU to prohibit access to this page |
145 | | */ |
146 | | void page_prohibit_access(void* page); |
147 | | |
148 | | /** |
149 | | * Set the MMU to allow R/W access to this page |
150 | | */ |
151 | | void page_allow_access(void* page); |
152 | | |
153 | | |
154 | | /** |
155 | | * Run a probe instruction to test for support for a CPU instruction. |
156 | | * Runs in system-specific env that catches illegal instructions; this |
157 | | * function always fails if the OS doesn't provide this. |
158 | | * Returns value of probe_fn, if it could run. |
159 | | * If error occurs, returns negative number. |
160 | | * This allows probe_fn to indicate errors of its own, if it wants. |
161 | | * For example the instruction might not only be only available on some |
162 | | * CPUs, but also buggy on some subset of these - the probe function |
163 | | * can test to make sure the instruction works properly before |
164 | | * indicating that the instruction is available. |
165 | | * |
166 | | * @warning on Unix systems uses signal handling in a way that is not |
167 | | * thread safe. It should only be called in a single-threaded context |
168 | | * (ie, at static init time). |
169 | | * |
170 | | * If probe_fn throws an exception the result is undefined. |
171 | | * |
172 | | * Return codes: |
173 | | * -1 illegal instruction detected |
174 | | */ |
175 | | int BOTAN_TEST_API run_cpu_instruction_probe(std::function<int ()> probe_fn); |
176 | | |
177 | | /** |
178 | | * Represents a terminal state |
179 | | */ |
180 | | class BOTAN_UNSTABLE_API Echo_Suppression |
181 | | { |
182 | | public: |
183 | | /** |
184 | | * Reenable echo on this terminal. Can be safely called |
185 | | * multiple times. May throw if an error occurs. |
186 | | */ |
187 | | virtual void reenable_echo() = 0; |
188 | | |
189 | | /** |
190 | | * Implicitly calls reenable_echo, but swallows/ignored all |
191 | | * errors which would leave the terminal in an invalid state. |
192 | | */ |
193 | 0 | virtual ~Echo_Suppression() = default; |
194 | | }; |
195 | | |
196 | | /** |
197 | | * Suppress echo on the terminal |
198 | | * Returns null if this operation is not supported on the current system. |
199 | | */ |
200 | | std::unique_ptr<Echo_Suppression> BOTAN_UNSTABLE_API suppress_echo_on_terminal(); |
201 | | |
202 | | } |
203 | | |
204 | | } |
205 | | |
206 | | #endif |