third_party/ulib/musl/src/network/getservbyname_r.c

#define _GNU_SOURCE
#include "lookup.h"
#include <errno.h>
#include <inttypes.h>
#include <netdb.h>
#include <netinet/in.h>
#include <string.h>
#include <sys/socket.h>

#define ALIGN        \
    (sizeof(struct { \
         char a;     \
         char* b;    \
     }) -            \
     sizeof(char*))

int getservbyname_r(const char* name, const char* prots, struct servent* se, char* buf,
                    size_t buflen, struct servent** res) {
    struct service servs[MAXSERVS];
    int cnt, proto, align;

    /* Align buffer */
    align = -(uintptr_t)buf & (ALIGN - 1);
    if (buflen < 2 * sizeof(char*) + align)
        return ERANGE;
    buf += align;

    if (!prots)
        proto = 0;
    else if (!strcmp(prots, "tcp"))
        proto = IPPROTO_TCP;
    else if (!strcmp(prots, "udp"))
        proto = IPPROTO_UDP;
    else
        return EINVAL;

    cnt = __lookup_serv(servs, name, proto, 0, 0);
    if (cnt < 0)
        switch (cnt) {
        case EAI_MEMORY:
        case EAI_SYSTEM:
            return ENOMEM;
        default:
            return ENOENT;
        }

    se->s_name = (char*)name;
    se->s_aliases = (void*)buf;
    se->s_aliases[0] = se->s_name;
    se->s_aliases[1] = 0;
    se->s_port = htons(servs[0].port);
    se->s_proto = (char*)(servs[0].proto == IPPROTO_TCP ? "tcp" : "udp");

    *res = se;
    return 0;
}