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#define _GNU_SOURCE
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <inttypes.h>
#include <errno.h>
#include <string.h>
int getservbyport_r(int port, const char *prots,
struct servent *se, char *buf, size_t buflen, struct servent **res)
{
int i;
struct sockaddr_in sin = {
.sin_family = AF_INET,
.sin_port = port,
};
if (!prots) return -(
getservbyport_r(port, "tcp", se, buf, buflen, res)
&& getservbyport_r(port, "udp", se, buf, buflen, res) );
/* Align buffer */
i = (uintptr_t)buf & sizeof(char *)-1;
if (!i) i = sizeof(char *);
if (buflen < 3*sizeof(char *)-i) {
errno = ERANGE;
return -1;
}
buf += sizeof(char *)-i;
buflen -= sizeof(char *)-i;
if (strcmp(prots, "tcp") && strcmp(prots, "udp")) return -1;
se->s_port = port;
se->s_proto = (char *)prots;
se->s_aliases = (void *)buf;
buf += 2*sizeof(char *);
buflen -= 2*sizeof(char *);
se->s_aliases[1] = 0;
se->s_aliases[0] = se->s_name = buf;
if (getnameinfo((void *)&sin, sizeof sin, 0, 0, buf, buflen,
strcmp(prots, "udp") ? 0 : NI_DGRAM) < 0) return -1;
*res = se;
return 0;
}
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