getaddrinfo_shim.c

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <string.h>

#include <dlfcn.h>


int getaddrinfo(const char *node, const char *service,
        const struct addrinfo *hints, struct addrinfo **res) {
    struct addrinfo my_hints;
    memcpy(&my_hints, hints, sizeof(struct addrinfo));
    my_hints.ai_family = AF_UNSPEC;

    int(*original_getaddrinfo)(const char *, const char *, const struct addrinfo *, struct addrinfo **);
    original_getaddrinfo = (int (*)(const char *, const char *, const struct addrinfo *, struct addrinfo **))
        dlsym(RTLD_NEXT, "getaddrinfo");
    if(original_getaddrinfo == NULL) {
        fprintf(stderr, "can't find getaddrinfo\n");
        abort();
    }

    (*original_getaddrinfo)(node, service, &my_hints, res);
}