Index: uspace/lib/c/Makefile =================================================================== --- uspace/lib/c/Makefile (revision 914c69344bd47cd9bdd70ec10555f3ab28b3c5ab) +++ uspace/lib/c/Makefile (revision 87337dc52aa5f13830c6e760d834e32ad660f9e8) @@ -133,4 +133,5 @@ generic/double_to_str.c \ generic/malloc.c \ + generic/rndgen.c \ generic/stdio/scanf.c \ generic/stdio/sprintf.c \ Index: uspace/lib/c/generic/rndgen.c =================================================================== --- uspace/lib/c/generic/rndgen.c (revision 87337dc52aa5f13830c6e760d834e32ad660f9e8) +++ uspace/lib/c/generic/rndgen.c (revision 87337dc52aa5f13830c6e760d834e32ad660f9e8) @@ -0,0 +1,121 @@ +/* + * Copyright (c) 2018 Jiri Svoboda + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** @addtogroup libc + * @{ + */ +/** + * @file + * @brief Random number generator. + * + * Generate random (as opposed to pseudorandom) numbers. This should be + * used sparingly (e.g. to seed a pseudorandom number generator). + */ + +#include +#include +#include +#include +#include + +/** Create random number generator. + * + * @param rrndgen Place to store new random number generator + * @return EOK on success or error code + */ +errno_t rndgen_create(rndgen_t **rrndgen) +{ + rndgen_t *rndgen; + struct timeval tv; + + rndgen = calloc(1, sizeof(rndgen_t)); + if (rndgen == NULL) + return ENOMEM; + + /* XXX This is a rather poor way of generating random numbers */ + gettimeofday(&tv, NULL); + rndgen->seed = tv.tv_sec ^ tv.tv_usec; + + *rrndgen = rndgen; + return EOK; +} + +/** Destroy random number generator. + * + * @param rndgen Random number generator or @c NULL + */ +void rndgen_destroy(rndgen_t *rndgen) +{ + if (rndgen == NULL) + return; + + free(rndgen); +} + +/** Generate random 8-bit integer. + * + * @param rndgen Random number generator + * @param rb Place to store random 8-bit integer + * @return EOK on success or error code + */ +errno_t rndgen_uint8(rndgen_t *rndgen, uint8_t *rb) +{ + rndgen->seed = (1366 * rndgen->seed + 150889) % 714025; + + *rb = rndgen->seed & 0xff; + return EOK; +} + +/** Generate random 32-bit integer. + * + * @param rndgen Random number generator + * @param rw Place to store random 32-bit integer + * @return EOK on success or error code + */ +errno_t rndgen_uint32(rndgen_t *rndgen, uint32_t *rw) +{ + int i; + uint8_t b; + uint32_t w; + errno_t rc; + + w = 0; + for (i = 0; i < 4; i++) { + rc = rndgen_uint8(rndgen, &b); + if (rc != EOK) + return rc; + + w = (w << 8) | b; + } + + *rw = w; + return EOK; +} + +/** @} + */ Index: uspace/lib/c/generic/uuid.c =================================================================== --- uspace/lib/c/generic/uuid.c (revision 914c69344bd47cd9bdd70ec10555f3ab28b3c5ab) +++ uspace/lib/c/generic/uuid.c (revision 87337dc52aa5f13830c6e760d834e32ad660f9e8) @@ -35,7 +35,7 @@ #include #include +#include #include #include -#include #include @@ -48,12 +48,18 @@ { int i; - struct timeval tv; + rndgen_t *rndgen; + errno_t rc; - /* XXX This is a rather poor way of generating random numbers */ - gettimeofday(&tv, NULL); - srand(tv.tv_sec ^ tv.tv_usec); + rc = rndgen_create(&rndgen); + if (rc != EOK) + return EIO; - for (i = 0; i < uuid_bytes; i++) - uuid->b[i] = rand(); + for (i = 0; i < uuid_bytes; i++) { + rc = rndgen_uint8(rndgen, &uuid->b[i]); + if (rc != EOK) { + rc = EIO; + goto error; + } + } /* Version 4 UUID from random or pseudo-random numbers */ @@ -62,4 +68,7 @@ return EOK; +error: + rndgen_destroy(rndgen); + return rc; } Index: uspace/lib/c/include/rndgen.h =================================================================== --- uspace/lib/c/include/rndgen.h (revision 87337dc52aa5f13830c6e760d834e32ad660f9e8) +++ uspace/lib/c/include/rndgen.h (revision 87337dc52aa5f13830c6e760d834e32ad660f9e8) @@ -0,0 +1,54 @@ +/* + * Copyright (c) 2018 Jiri Svoboda + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +/** @addtogroup libc + * @{ + */ +/** @file Random number generator + */ + +#ifndef LIBC_RNDGEN_H_ +#define LIBC_RNDGEN_H_ + +#include +#include +#include + +typedef struct { + unsigned int seed; +} rndgen_t; + +extern errno_t rndgen_create(rndgen_t **); +extern void rndgen_destroy(rndgen_t *); +extern errno_t rndgen_uint8(rndgen_t *, uint8_t *); +extern errno_t rndgen_uint32(rndgen_t *, uint32_t *); + +#endif + +/** @} + */