nsprpub/pr/include/prrng.h@44a2da4a2ab2 (annotated)
nsprpub/pr/include/prrng.h
Fri, 16 Jan 2015 04:50:19 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Fri, 16 Jan 2015 04:50:19 +0100
- branch
- TOR_BUG_9701
- changeset 13
- 44a2da4a2ab2
- permissions
- -rw-r--r--
Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | |
| michael@0 | 7 | /* |
| michael@0 | 8 | ** prrng.h -- NSPR Random Number Generator |
| michael@0 | 9 | ** |
| michael@0 | 10 | ** |
| michael@0 | 11 | ** lth. 29-Oct-1999. |
| michael@0 | 12 | */ |
| michael@0 | 13 | |
| michael@0 | 14 | #ifndef prrng_h___ |
| michael@0 | 15 | #define prrng_h___ |
| michael@0 | 16 | |
| michael@0 | 17 | #include "prtypes.h" |
| michael@0 | 18 | |
| michael@0 | 19 | PR_BEGIN_EXTERN_C |
| michael@0 | 20 | |
| michael@0 | 21 | /* |
| michael@0 | 22 | ** PR_GetRandomNoise() -- Get random noise from the host platform |
| michael@0 | 23 | ** |
| michael@0 | 24 | ** Description: |
| michael@0 | 25 | ** PR_GetRandomNoise() provides, depending on platform, a random value. |
| michael@0 | 26 | ** The length of the random value is dependent on platform and the |
| michael@0 | 27 | ** platform's ability to provide a random value at that moment. |
| michael@0 | 28 | ** |
| michael@0 | 29 | ** The intent of PR_GetRandomNoise() is to provide a "seed" value for a |
| michael@0 | 30 | ** another random number generator that may be suitable for |
| michael@0 | 31 | ** cryptographic operations. This implies that the random value |
| michael@0 | 32 | ** provided may not be, by itself, cryptographically secure. The value |
| michael@0 | 33 | ** generated by PR_GetRandomNoise() is at best, extremely difficult to |
| michael@0 | 34 | ** predict and is as non-deterministic as the underlying platfrom can |
| michael@0 | 35 | ** provide. |
| michael@0 | 36 | ** |
| michael@0 | 37 | ** Inputs: |
| michael@0 | 38 | ** buf -- pointer to a caller supplied buffer to contain the |
| michael@0 | 39 | ** generated random number. buf must be at least as large as |
| michael@0 | 40 | ** is specified in the 'size' argument. |
| michael@0 | 41 | ** |
| michael@0 | 42 | ** size -- the requested size of the generated random number |
| michael@0 | 43 | ** |
| michael@0 | 44 | ** Outputs: |
| michael@0 | 45 | ** a random number provided in 'buf'. |
| michael@0 | 46 | ** |
| michael@0 | 47 | ** Returns: |
| michael@0 | 48 | ** PRSize value equal to the size of the random number actually |
| michael@0 | 49 | ** generated, or zero. The generated size may be less than the size |
| michael@0 | 50 | ** requested. A return value of zero means that PR_GetRandomNoise() is |
| michael@0 | 51 | ** not implemented on this platform, or there is no available noise |
| michael@0 | 52 | ** available to be returned at the time of the call. |
| michael@0 | 53 | ** |
| michael@0 | 54 | ** Restrictions: |
| michael@0 | 55 | ** Calls to PR_GetRandomNoise() may use a lot of CPU on some platforms. |
| michael@0 | 56 | ** Some platforms may block for up to a few seconds while they |
| michael@0 | 57 | ** accumulate some noise. Busy machines generate lots of noise, but |
| michael@0 | 58 | ** care is advised when using PR_GetRandomNoise() frequently in your |
| michael@0 | 59 | ** application. |
| michael@0 | 60 | ** |
| michael@0 | 61 | ** History: |
| michael@0 | 62 | ** Parts of the model dependent implementation for PR_GetRandomNoise() |
| michael@0 | 63 | ** were taken in whole or part from code previously in Netscape's NSS |
| michael@0 | 64 | ** component. |
| michael@0 | 65 | ** |
| michael@0 | 66 | */ |
| michael@0 | 67 | NSPR_API(PRSize) PR_GetRandomNoise( |
| michael@0 | 68 | void *buf, |
| michael@0 | 69 | PRSize size |
| michael@0 | 70 | ); |
| michael@0 | 71 | |
| michael@0 | 72 | PR_END_EXTERN_C |
| michael@0 | 73 | |
| michael@0 | 74 | #endif /* prrng_h___ */ |
| michael@0 | 75 | /* end prrng.h */ |
