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util-src/crand.c @ 11769:071715a18394
mod_pubsub: Move reversal of item order in <items>
Examples in XEP-0060 suggest that items should be listed in
chronological order, but we get them from the archive in reverse
order.
However when requesting specific items by id the results keep that
order and we don't want to flip it again.
At some point it would likely be best to use the archive API directly
instead of this util.cache-compatible wrapper.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sun, 05 Sep 2021 18:42:44 +0200 |
parent | 8451:770f79a9635c |
child | 12470:80f3123053e2 |
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/* Prosody IM -- Copyright (C) 2008-2017 Matthew Wild -- Copyright (C) 2008-2017 Waqas Hussain -- Copyright (C) 2016-2017 Kim Alvefur -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- */ /* * crand.c * C PRNG interface * * The purpose of this module is to provide access to a PRNG in * environments without /dev/urandom * * Caution! This has not been extensively tested. * */ #define _DEFAULT_SOURCE #include <stdlib.h> #include <string.h> #include <errno.h> #include "lualib.h" #include "lauxlib.h" #if defined(WITH_GETRANDOM) #ifndef __GLIBC_PREREQ /* Not compiled with glibc at all */ #define __GLIBC_PREREQ(a,b) 0 #endif #if ! __GLIBC_PREREQ(2,25) /* Not compiled with a glibc that provides getrandom() */ #include <unistd.h> #include <sys/syscall.h> #ifndef SYS_getrandom #error getrandom() requires Linux 3.17 or later #endif /* This wasn't present before glibc 2.25 */ int getrandom(void *buf, size_t buflen, unsigned int flags) { return syscall(SYS_getrandom, buf, buflen, flags); } #else #include <sys/random.h> #endif #elif defined(WITH_OPENSSL) #include <openssl/rand.h> #elif defined(WITH_ARC4RANDOM) #ifdef __linux__ #include <bsd/stdlib.h> #endif #else #error util.crand compiled without a random source #endif #ifndef SMALLBUFSIZ #define SMALLBUFSIZ 32 #endif int Lrandom(lua_State *L) { char smallbuf[SMALLBUFSIZ]; char *buf = &smallbuf[0]; const lua_Integer l = luaL_checkinteger(L, 1); const size_t len = l; luaL_argcheck(L, l >= 0, 1, "must be > 0"); if(len == 0) { lua_pushliteral(L, ""); return 1; } if(len > SMALLBUFSIZ) { buf = lua_newuserdata(L, len); } #if defined(WITH_GETRANDOM) /* * This acts like a read from /dev/urandom with the exception that it * *does* block if the entropy pool is not yet initialized. */ int left = len; char *p = buf; do { int ret = getrandom(p, left, 0); if(ret < 0) { lua_pushstring(L, strerror(errno)); return lua_error(L); } p += ret; left -= ret; } while(left > 0); #elif defined(WITH_ARC4RANDOM) arc4random_buf(buf, len); #elif defined(WITH_OPENSSL) if(!RAND_status()) { lua_pushliteral(L, "OpenSSL PRNG not seeded"); return lua_error(L); } if(RAND_bytes((unsigned char *)buf, len) != 1) { /* TODO ERR_get_error() */ lua_pushstring(L, "RAND_bytes() failed"); return lua_error(L); } #endif lua_pushlstring(L, buf, len); return 1; } int luaopen_util_crand(lua_State *L) { #if (LUA_VERSION_NUM > 501) luaL_checkversion(L); #endif lua_createtable(L, 0, 2); lua_pushcfunction(L, Lrandom); lua_setfield(L, -2, "bytes"); #if defined(WITH_GETRANDOM) lua_pushstring(L, "Linux"); #elif defined(WITH_ARC4RANDOM) lua_pushstring(L, "arc4random()"); #elif defined(WITH_OPENSSL) lua_pushstring(L, "OpenSSL"); #endif lua_setfield(L, -2, "_source"); return 1; }