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Diffstat (limited to 'libevent-2.0.20-stable/include/event2/util.h')
| -rw-r--r-- | libevent-2.0.20-stable/include/event2/util.h | 695 |
1 files changed, 695 insertions, 0 deletions
diff --git a/libevent-2.0.20-stable/include/event2/util.h b/libevent-2.0.20-stable/include/event2/util.h new file mode 100644 index 0000000..4b7e8b4 --- /dev/null +++ b/libevent-2.0.20-stable/include/event2/util.h @@ -0,0 +1,695 @@ +/* + * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * 3. 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. + */ +#ifndef _EVENT2_UTIL_H_ +#define _EVENT2_UTIL_H_ + +/** @file event2/util.h + + Common convenience functions for cross-platform portability and + related socket manipulations. + + */ + +#ifdef __cplusplus +extern "C" { +#endif + +#include <event2/event-config.h> +#ifdef _EVENT_HAVE_SYS_TIME_H +#include <sys/time.h> +#endif +#ifdef _EVENT_HAVE_STDINT_H +#include <stdint.h> +#elif defined(_EVENT_HAVE_INTTYPES_H) +#include <inttypes.h> +#endif +#ifdef _EVENT_HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef _EVENT_HAVE_STDDEF_H +#include <stddef.h> +#endif +#ifdef _MSC_VER +#include <BaseTsd.h> +#endif +#include <stdarg.h> +#ifdef _EVENT_HAVE_NETDB_H +#if !defined(_GNU_SOURCE) +#define _GNU_SOURCE +#endif +#include <netdb.h> +#endif + +#ifdef WIN32 +#include <winsock2.h> +#else +#include <sys/socket.h> +#endif + +/* Some openbsd autoconf versions get the name of this macro wrong. */ +#if defined(_EVENT_SIZEOF_VOID__) && !defined(_EVENT_SIZEOF_VOID_P) +#define _EVENT_SIZEOF_VOID_P _EVENT_SIZEOF_VOID__ +#endif + +/** + * @name Standard integer types. + * + * Integer type definitions for types that are supposed to be defined in the + * C99-specified stdint.h. Shamefully, some platforms do not include + * stdint.h, so we need to replace it. (If you are on a platform like this, + * your C headers are now over 10 years out of date. You should bug them to + * do something about this.) + * + * We define: + * + * <dl> + * <dt>ev_uint64_t, ev_uint32_t, ev_uint16_t, ev_uint8_t</dt> + * <dd>unsigned integer types of exactly 64, 32, 16, and 8 bits + * respectively.</dd> + * <dt>ev_int64_t, ev_int32_t, ev_int16_t, ev_int8_t</dt> + * <dd>signed integer types of exactly 64, 32, 16, and 8 bits + * respectively.</dd> + * <dt>ev_uintptr_t, ev_intptr_t</dt> + * <dd>unsigned/signed integers large enough + * to hold a pointer without loss of bits.</dd> + * <dt>ev_ssize_t</dt> + * <dd>A signed type of the same size as size_t</dd> + * <dt>ev_off_t</dt> + * <dd>A signed type typically used to represent offsets within a + * (potentially large) file</dd> + * + * @{ + */ +#ifdef _EVENT_HAVE_UINT64_T +#define ev_uint64_t uint64_t +#define ev_int64_t int64_t +#elif defined(WIN32) +#define ev_uint64_t unsigned __int64 +#define ev_int64_t signed __int64 +#elif _EVENT_SIZEOF_LONG_LONG == 8 +#define ev_uint64_t unsigned long long +#define ev_int64_t long long +#elif _EVENT_SIZEOF_LONG == 8 +#define ev_uint64_t unsigned long +#define ev_int64_t long +#elif defined(_EVENT_IN_DOXYGEN) +#define ev_uint64_t ... +#define ev_int64_t ... +#else +#error "No way to define ev_uint64_t" +#endif + +#ifdef _EVENT_HAVE_UINT32_T +#define ev_uint32_t uint32_t +#define ev_int32_t int32_t +#elif defined(WIN32) +#define ev_uint32_t unsigned int +#define ev_int32_t signed int +#elif _EVENT_SIZEOF_LONG == 4 +#define ev_uint32_t unsigned long +#define ev_int32_t signed long +#elif _EVENT_SIZEOF_INT == 4 +#define ev_uint32_t unsigned int +#define ev_int32_t signed int +#elif defined(_EVENT_IN_DOXYGEN) +#define ev_uint32_t ... +#define ev_int32_t ... +#else +#error "No way to define ev_uint32_t" +#endif + +#ifdef _EVENT_HAVE_UINT16_T +#define ev_uint16_t uint16_t +#define ev_int16_t int16_t +#elif defined(WIN32) +#define ev_uint16_t unsigned short +#define ev_int16_t signed short +#elif _EVENT_SIZEOF_INT == 2 +#define ev_uint16_t unsigned int +#define ev_int16_t signed int +#elif _EVENT_SIZEOF_SHORT == 2 +#define ev_uint16_t unsigned short +#define ev_int16_t signed short +#elif defined(_EVENT_IN_DOXYGEN) +#define ev_uint16_t ... +#define ev_int16_t ... +#else +#error "No way to define ev_uint16_t" +#endif + +#ifdef _EVENT_HAVE_UINT8_T +#define ev_uint8_t uint8_t +#define ev_int8_t int8_t +#elif defined(_EVENT_IN_DOXYGEN) +#define ev_uint8_t ... +#define ev_int8_t ... +#else +#define ev_uint8_t unsigned char +#define ev_int8_t signed char +#endif + +#ifdef _EVENT_HAVE_UINTPTR_T +#define ev_uintptr_t uintptr_t +#define ev_intptr_t intptr_t +#elif _EVENT_SIZEOF_VOID_P <= 4 +#define ev_uintptr_t ev_uint32_t +#define ev_intptr_t ev_int32_t +#elif _EVENT_SIZEOF_VOID_P <= 8 +#define ev_uintptr_t ev_uint64_t +#define ev_intptr_t ev_int64_t +#elif defined(_EVENT_IN_DOXYGEN) +#define ev_uintptr_t ... +#define ev_intptr_t ... +#else +#error "No way to define ev_uintptr_t" +#endif + +#ifdef _EVENT_ssize_t +#define ev_ssize_t _EVENT_ssize_t +#else +#define ev_ssize_t ssize_t +#endif + +#ifdef WIN32 +#define ev_off_t ev_int64_t +#else +#define ev_off_t off_t +#endif +/**@}*/ + +/* Limits for integer types. + + We're making two assumptions here: + - The compiler does constant folding properly. + - The platform does signed arithmetic in two's complement. +*/ + +/** + @name Limits for integer types + + These macros hold the largest or smallest values possible for the + ev_[u]int*_t types. + + @{ +*/ +#define EV_UINT64_MAX ((((ev_uint64_t)0xffffffffUL) << 32) | 0xffffffffUL) +#define EV_INT64_MAX ((((ev_int64_t) 0x7fffffffL) << 32) | 0xffffffffL) +#define EV_INT64_MIN ((-EV_INT64_MAX) - 1) +#define EV_UINT32_MAX ((ev_uint32_t)0xffffffffUL) +#define EV_INT32_MAX ((ev_int32_t) 0x7fffffffL) +#define EV_INT32_MIN ((-EV_INT32_MAX) - 1) +#define EV_UINT16_MAX ((ev_uint16_t)0xffffUL) +#define EV_INT16_MAX ((ev_int16_t) 0x7fffL) +#define EV_INT16_MIN ((-EV_INT16_MAX) - 1) +#define EV_UINT8_MAX 255 +#define EV_INT8_MAX 127 +#define EV_INT8_MIN ((-EV_INT8_MAX) - 1) +/** @} */ + +/** + @name Limits for SIZE_T and SSIZE_T + + @{ +*/ +#if _EVENT_SIZEOF_SIZE_T == 8 +#define EV_SIZE_MAX EV_UINT64_MAX +#define EV_SSIZE_MAX EV_INT64_MAX +#elif _EVENT_SIZEOF_SIZE_T == 4 +#define EV_SIZE_MAX EV_UINT32_MAX +#define EV_SSIZE_MAX EV_INT32_MAX +#elif defined(_EVENT_IN_DOXYGEN) +#define EV_SIZE_MAX ... +#define EV_SSIZE_MAX ... +#else +#error "No way to define SIZE_MAX" +#endif + +#define EV_SSIZE_MIN ((-EV_SSIZE_MAX) - 1) +/**@}*/ + +#ifdef WIN32 +#define ev_socklen_t int +#elif defined(_EVENT_socklen_t) +#define ev_socklen_t _EVENT_socklen_t +#else +#define ev_socklen_t socklen_t +#endif + +#ifdef _EVENT_HAVE_STRUCT_SOCKADDR_STORAGE___SS_FAMILY +#if !defined(_EVENT_HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY) \ + && !defined(ss_family) +#define ss_family __ss_family +#endif +#endif + +/** + * A type wide enough to hold the output of "socket()" or "accept()". On + * Windows, this is an intptr_t; elsewhere, it is an int. */ +#ifdef WIN32 +#define evutil_socket_t intptr_t +#else +#define evutil_socket_t int +#endif + +/** Create two new sockets that are connected to each other. + + On Unix, this simply calls socketpair(). On Windows, it uses the + loopback network interface on 127.0.0.1, and only + AF_INET,SOCK_STREAM are supported. + + (This may fail on some Windows hosts where firewall software has cleverly + decided to keep 127.0.0.1 from talking to itself.) + + Parameters and return values are as for socketpair() +*/ +int evutil_socketpair(int d, int type, int protocol, evutil_socket_t sv[2]); +/** Do platform-specific operations as needed to make a socket nonblocking. + + @param sock The socket to make nonblocking + @return 0 on success, -1 on failure + */ +int evutil_make_socket_nonblocking(evutil_socket_t sock); + +/** Do platform-specific operations to make a listener socket reusable. + + Specifically, we want to make sure that another program will be able + to bind this address right after we've closed the listener. + + This differs from Windows's interpretation of "reusable", which + allows multiple listeners to bind the same address at the same time. + + @param sock The socket to make reusable + @return 0 on success, -1 on failure + */ +int evutil_make_listen_socket_reuseable(evutil_socket_t sock); + +/** Do platform-specific operations as needed to close a socket upon a + successful execution of one of the exec*() functions. + + @param sock The socket to be closed + @return 0 on success, -1 on failure + */ +int evutil_make_socket_closeonexec(evutil_socket_t sock); + +/** Do the platform-specific call needed to close a socket returned from + socket() or accept(). + + @param sock The socket to be closed + @return 0 on success, -1 on failure + */ +int evutil_closesocket(evutil_socket_t sock); +#define EVUTIL_CLOSESOCKET(s) evutil_closesocket(s) + + +#ifdef WIN32 +/** Return the most recent socket error. Not idempotent on all platforms. */ +#define EVUTIL_SOCKET_ERROR() WSAGetLastError() +/** Replace the most recent socket error with errcode */ +#define EVUTIL_SET_SOCKET_ERROR(errcode) \ + do { WSASetLastError(errcode); } while (0) +/** Return the most recent socket error to occur on sock. */ +int evutil_socket_geterror(evutil_socket_t sock); +/** Convert a socket error to a string. */ +const char *evutil_socket_error_to_string(int errcode); +#elif defined(_EVENT_IN_DOXYGEN) +/** + @name Socket error functions + + These functions are needed for making programs compatible between + Windows and Unix-like platforms. + + You see, Winsock handles socket errors differently from the rest of + the world. Elsewhere, a socket error is like any other error and is + stored in errno. But winsock functions require you to retrieve the + error with a special function, and don't let you use strerror for + the error codes. And handling EWOULDBLOCK is ... different. + + @{ +*/ +/** Return the most recent socket error. Not idempotent on all platforms. */ +#define EVUTIL_SOCKET_ERROR() ... +/** Replace the most recent socket error with errcode */ +#define EVUTIL_SET_SOCKET_ERROR(errcode) ... +/** Return the most recent socket error to occur on sock. */ +#define evutil_socket_geterror(sock) ... +/** Convert a socket error to a string. */ +#define evutil_socket_error_to_string(errcode) ... +/**@}*/ +#else +#define EVUTIL_SOCKET_ERROR() (errno) +#define EVUTIL_SET_SOCKET_ERROR(errcode) \ + do { errno = (errcode); } while (0) +#define evutil_socket_geterror(sock) (errno) +#define evutil_socket_error_to_string(errcode) (strerror(errcode)) +#endif + + +/** + * @name Manipulation macros for struct timeval. + * + * We define replacements + * for timeradd, timersub, timerclear, timercmp, and timerisset. + * + * @{ + */ +#ifdef _EVENT_HAVE_TIMERADD +#define evutil_timeradd(tvp, uvp, vvp) timeradd((tvp), (uvp), (vvp)) +#define evutil_timersub(tvp, uvp, vvp) timersub((tvp), (uvp), (vvp)) +#else +#define evutil_timeradd(tvp, uvp, vvp) \ + do { \ + (vvp)->tv_sec = (tvp)->tv_sec + (uvp)->tv_sec; \ + (vvp)->tv_usec = (tvp)->tv_usec + (uvp)->tv_usec; \ + if ((vvp)->tv_usec >= 1000000) { \ + (vvp)->tv_sec++; \ + (vvp)->tv_usec -= 1000000; \ + } \ + } while (0) +#define evutil_timersub(tvp, uvp, vvp) \ + do { \ + (vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec; \ + (vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec; \ + if ((vvp)->tv_usec < 0) { \ + (vvp)->tv_sec--; \ + (vvp)->tv_usec += 1000000; \ + } \ + } while (0) +#endif /* !_EVENT_HAVE_HAVE_TIMERADD */ + +#ifdef _EVENT_HAVE_TIMERCLEAR +#define evutil_timerclear(tvp) timerclear(tvp) +#else +#define evutil_timerclear(tvp) (tvp)->tv_sec = (tvp)->tv_usec = 0 +#endif +/**@}*/ + +/** Return true iff the tvp is related to uvp according to the relational + * operator cmp. Recognized values for cmp are ==, <=, <, >=, and >. */ +#define evutil_timercmp(tvp, uvp, cmp) \ + (((tvp)->tv_sec == (uvp)->tv_sec) ? \ + ((tvp)->tv_usec cmp (uvp)->tv_usec) : \ + ((tvp)->tv_sec cmp (uvp)->tv_sec)) + +#ifdef _EVENT_HAVE_TIMERISSET +#define evutil_timerisset(tvp) timerisset(tvp) +#else +#define evutil_timerisset(tvp) ((tvp)->tv_sec || (tvp)->tv_usec) +#endif + +/** Replacement for offsetof on platforms that don't define it. */ +#ifdef offsetof +#define evutil_offsetof(type, field) offsetof(type, field) +#else +#define evutil_offsetof(type, field) ((off_t)(&((type *)0)->field)) +#endif + +/* big-int related functions */ +/** Parse a 64-bit value from a string. Arguments are as for strtol. */ +ev_int64_t evutil_strtoll(const char *s, char **endptr, int base); + +/** Replacement for gettimeofday on platforms that lack it. */ +#ifdef _EVENT_HAVE_GETTIMEOFDAY +#define evutil_gettimeofday(tv, tz) gettimeofday((tv), (tz)) +#else +struct timezone; +int evutil_gettimeofday(struct timeval *tv, struct timezone *tz); +#endif + +/** Replacement for snprintf to get consistent behavior on platforms for + which the return value of snprintf does not conform to C99. + */ +int evutil_snprintf(char *buf, size_t buflen, const char *format, ...) +#ifdef __GNUC__ + __attribute__((format(printf, 3, 4))) +#endif +; +/** Replacement for vsnprintf to get consistent behavior on platforms for + which the return value of snprintf does not conform to C99. + */ +int evutil_vsnprintf(char *buf, size_t buflen, const char *format, va_list ap) +#ifdef __GNUC__ + __attribute__((format(printf, 3, 0))) +#endif +; + +/** Replacement for inet_ntop for platforms which lack it. */ +const char *evutil_inet_ntop(int af, const void *src, char *dst, size_t len); +/** Replacement for inet_pton for platforms which lack it. */ +int evutil_inet_pton(int af, const char *src, void *dst); +struct sockaddr; + +/** Parse an IPv4 or IPv6 address, with optional port, from a string. + + Recognized formats are: + - [IPv6Address]:port + - [IPv6Address] + - IPv6Address + - IPv4Address:port + - IPv4Address + + If no port is specified, the port in the output is set to 0. + + @param str The string to parse. + @param out A struct sockaddr to hold the result. This should probably be + a struct sockaddr_storage. + @param outlen A pointer to the number of bytes that that 'out' can safely + hold. Set to the number of bytes used in 'out' on success. + @return -1 if the address is not well-formed, if the port is out of range, + or if out is not large enough to hold the result. Otherwise returns + 0 on success. +*/ +int evutil_parse_sockaddr_port(const char *str, struct sockaddr *out, int *outlen); + +/** Compare two sockaddrs; return 0 if they are equal, or less than 0 if sa1 + * preceeds sa2, or greater than 0 if sa1 follows sa2. If include_port is + * true, consider the port as well as the address. Only implemented for + * AF_INET and AF_INET6 addresses. The ordering is not guaranteed to remain + * the same between Libevent versions. */ +int evutil_sockaddr_cmp(const struct sockaddr *sa1, const struct sockaddr *sa2, + int include_port); + +/** As strcasecmp, but always compares the characters in locale-independent + ASCII. That's useful if you're handling data in ASCII-based protocols. + */ +int evutil_ascii_strcasecmp(const char *str1, const char *str2); +/** As strncasecmp, but always compares the characters in locale-independent + ASCII. That's useful if you're handling data in ASCII-based protocols. + */ +int evutil_ascii_strncasecmp(const char *str1, const char *str2, size_t n); + +/* Here we define evutil_addrinfo to the native addrinfo type, or redefine it + * if this system has no getaddrinfo(). */ +#ifdef _EVENT_HAVE_STRUCT_ADDRINFO +#define evutil_addrinfo addrinfo +#else +/** A definition of struct addrinfo for systems that lack it. + + (This is just an alias for struct addrinfo if the system defines + struct addrinfo.) +*/ +struct evutil_addrinfo { + int ai_flags; /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */ + int ai_family; /* PF_xxx */ + int ai_socktype; /* SOCK_xxx */ + int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */ + size_t ai_addrlen; /* length of ai_addr */ + char *ai_canonname; /* canonical name for nodename */ + struct sockaddr *ai_addr; /* binary address */ + struct evutil_addrinfo *ai_next; /* next structure in linked list */ +}; +#endif +/** @name evutil_getaddrinfo() error codes + + These values are possible error codes for evutil_getaddrinfo() and + related functions. + + @{ +*/ +#ifdef EAI_ADDRFAMILY +#define EVUTIL_EAI_ADDRFAMILY EAI_ADDRFAMILY +#else +#define EVUTIL_EAI_ADDRFAMILY -901 +#endif +#ifdef EAI_AGAIN +#define EVUTIL_EAI_AGAIN EAI_AGAIN +#else +#define EVUTIL_EAI_AGAIN -902 +#endif +#ifdef EAI_BADFLAGS +#define EVUTIL_EAI_BADFLAGS EAI_BADFLAGS +#else +#define EVUTIL_EAI_BADFLAGS -903 +#endif +#ifdef EAI_FAIL +#define EVUTIL_EAI_FAIL EAI_FAIL +#else +#define EVUTIL_EAI_FAIL -904 +#endif +#ifdef EAI_FAMILY +#define EVUTIL_EAI_FAMILY EAI_FAMILY +#else +#define EVUTIL_EAI_FAMILY -905 +#endif +#ifdef EAI_MEMORY +#define EVUTIL_EAI_MEMORY EAI_MEMORY +#else +#define EVUTIL_EAI_MEMORY -906 +#endif +/* This test is a bit complicated, since some MS SDKs decide to + * remove NODATA or redefine it to be the same as NONAME, in a + * fun interpretation of RFC 2553 and RFC 3493. */ +#if defined(EAI_NODATA) && (!defined(EAI_NONAME) || EAI_NODATA != EAI_NONAME) +#define EVUTIL_EAI_NODATA EAI_NODATA +#else +#define EVUTIL_EAI_NODATA -907 +#endif +#ifdef EAI_NONAME +#define EVUTIL_EAI_NONAME EAI_NONAME +#else +#define EVUTIL_EAI_NONAME -908 +#endif +#ifdef EAI_SERVICE +#define EVUTIL_EAI_SERVICE EAI_SERVICE +#else +#define EVUTIL_EAI_SERVICE -909 +#endif +#ifdef EAI_SOCKTYPE +#define EVUTIL_EAI_SOCKTYPE EAI_SOCKTYPE +#else +#define EVUTIL_EAI_SOCKTYPE -910 +#endif +#ifdef EAI_SYSTEM +#define EVUTIL_EAI_SYSTEM EAI_SYSTEM +#else +#define EVUTIL_EAI_SYSTEM -911 +#endif + +#define EVUTIL_EAI_CANCEL -90001 + +#ifdef AI_PASSIVE +#define EVUTIL_AI_PASSIVE AI_PASSIVE +#else +#define EVUTIL_AI_PASSIVE 0x1000 +#endif +#ifdef AI_CANONNAME +#define EVUTIL_AI_CANONNAME AI_CANONNAME +#else +#define EVUTIL_AI_CANONNAME 0x2000 +#endif +#ifdef AI_NUMERICHOST +#define EVUTIL_AI_NUMERICHOST AI_NUMERICHOST +#else +#define EVUTIL_AI_NUMERICHOST 0x4000 +#endif +#ifdef AI_NUMERICSERV +#define EVUTIL_AI_NUMERICSERV AI_NUMERICSERV +#else +#define EVUTIL_AI_NUMERICSERV 0x8000 +#endif +#ifdef AI_V4MAPPED +#define EVUTIL_AI_V4MAPPED AI_V4MAPPED +#else +#define EVUTIL_AI_V4MAPPED 0x10000 +#endif +#ifdef AI_ALL +#define EVUTIL_AI_ALL AI_ALL +#else +#define EVUTIL_AI_ALL 0x20000 +#endif +#ifdef AI_ADDRCONFIG +#define EVUTIL_AI_ADDRCONFIG AI_ADDRCONFIG +#else +#define EVUTIL_AI_ADDRCONFIG 0x40000 +#endif +/**@}*/ + +struct evutil_addrinfo; +/** + * This function clones getaddrinfo for systems that don't have it. For full + * details, see RFC 3493, section 6.1. + * + * Limitations: + * - When the system has no getaddrinfo, we fall back to gethostbyname_r or + * gethostbyname, with their attendant issues. + * - The AI_V4MAPPED and AI_ALL flags are not currently implemented. + * + * For a nonblocking variant, see evdns_getaddrinfo. + */ +int evutil_getaddrinfo(const char *nodename, const char *servname, + const struct evutil_addrinfo *hints_in, struct evutil_addrinfo **res); + +/** Release storage allocated by evutil_getaddrinfo or evdns_getaddrinfo. */ +void evutil_freeaddrinfo(struct evutil_addrinfo *ai); + +const char *evutil_gai_strerror(int err); + +/** Generate n bytes of secure pseudorandom data, and store them in buf. + * + * By default, Libevent uses an ARC4-based random number generator, seeded + * using the platform's entropy source (/dev/urandom on Unix-like systems; + * CryptGenRandom on Windows). + */ +void evutil_secure_rng_get_bytes(void *buf, size_t n); + +/** + * Seed the secure random number generator if needed, and return 0 on + * success or -1 on failure. + * + * It is okay to call this function more than once; it will still return + * 0 if the RNG has been successfully seeded and -1 if it can't be + * seeded. + * + * Ordinarily you don't need to call this function from your own code; + * Libevent will seed the RNG itself the first time it needs good random + * numbers. You only need to call it if (a) you want to double-check + * that one of the seeding methods did succeed, or (b) you plan to drop + * the capability to seed (by chrooting, or dropping capabilities, or + * whatever), and you want to make sure that seeding happens before your + * program loses the ability to do it. + */ +int evutil_secure_rng_init(void); + +/** Seed the random number generator with extra random bytes. + + You should almost never need to call this function; it should be + sufficient to invoke evutil_secure_rng_init(), or let Libevent take + care of calling evutil_secure_rng_init() on its own. + + If you call this function as a _replacement_ for the regular + entropy sources, then you need to be sure that your input + contains a fairly large amount of strong entropy. Doing so is + notoriously hard: most people who try get it wrong. Watch out! + + @param dat a buffer full of a strong source of random numbers + @param datlen the number of bytes to read from datlen + */ +void evutil_secure_rng_add_bytes(const char *dat, size_t datlen); + +#ifdef __cplusplus +} +#endif + +#endif /* _EVUTIL_H_ */ |