source: asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/network/gethostbyaddr_r.c@ 352

#define _GNU_SOURCE

#include <sys/socket.h>
#include <netdb.h>
#include <string.h>
#include <netinet/in.h>
#include <errno.h>
#include <inttypes.h>

int gethostbyaddr_r(const void *a, socklen_t l, int af,
        struct hostent *h, char *buf, size_t buflen,
        struct hostent **res, int *err)
{
        union {
                struct sockaddr_in sin;
                struct sockaddr_in6 sin6;
        } sa = { .sin.sin_family = af };
        socklen_t sl = af==AF_INET6 ? sizeof sa.sin6 : sizeof sa.sin;
        int i;

        *res = 0;

        /* Load address argument into sockaddr structure */
        if (af==AF_INET6 && l==16) memcpy(&sa.sin6.sin6_addr, a, 16);
        else if (af==AF_INET && l==4) memcpy(&sa.sin.sin_addr, a, 4);
        else {
                *err = NO_RECOVERY;
                return EINVAL;
        }

        /* Align buffer and check for space for pointers and ip address */
        i = (uintptr_t)buf & sizeof(char *)-1;
        if (!i) i = sizeof(char *);
        if (buflen <= 5*sizeof(char *)-i + l) return ERANGE;
        buf += sizeof(char *)-i;
        buflen -= 5*sizeof(char *)-i + l;

        h->h_addr_list = (void *)buf;
        buf += 2*sizeof(char *);
        h->h_aliases = (void *)buf;
        buf += 2*sizeof(char *);

        h->h_addr_list[0] = buf;
        memcpy(h->h_addr_list[0], a, l);
        buf += l;
        h->h_addr_list[1] = 0;
        h->h_aliases[0] = buf;
        h->h_aliases[1] = 0;

        switch (getnameinfo((void *)&sa, sl, buf, buflen, 0, 0, 0)) {
        case EAI_AGAIN:
                *err = TRY_AGAIN;
                return EAGAIN;
        case EAI_OVERFLOW:
                return ERANGE;
        default:
        case EAI_MEMORY:
        case EAI_SYSTEM:
        case EAI_FAIL:
                *err = NO_RECOVERY;
                return errno;
        case 0:
                break;
        }

        h->h_addrtype = af;
        h->h_length = l;
        h->h_name = h->h_aliases[0];
        *res = h;
        return 0;
}