+int sockaddr_pretty(const struct sockaddr *_sa, socklen_t salen, bool translate_ipv6, char **ret) {
+ union sockaddr_union *sa = (union sockaddr_union*) _sa;
+ char *p;
+
+ assert(sa);
+ assert(salen >= sizeof(sa->sa.sa_family));
+
+ switch (sa->sa.sa_family) {
+
+ case AF_INET: {
+ uint32_t a;
+
+ a = ntohl(sa->in.sin_addr.s_addr);
+
+ if (asprintf(&p,
+ "%u.%u.%u.%u:%u",
+ a >> 24, (a >> 16) & 0xFF, (a >> 8) & 0xFF, a & 0xFF,
+ ntohs(sa->in.sin_port)) < 0)
+ return -ENOMEM;
+
+ break;
+ }
+
+ case AF_INET6: {
+ static const unsigned char ipv4_prefix[] = {
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF
+ };
+
+ if (translate_ipv6 && memcmp(&sa->in6.sin6_addr, ipv4_prefix, sizeof(ipv4_prefix)) == 0) {
+ const uint8_t *a = sa->in6.sin6_addr.s6_addr+12;
+
+ if (asprintf(&p,
+ "%u.%u.%u.%u:%u",
+ a[0], a[1], a[2], a[3],
+ ntohs(sa->in6.sin6_port)) < 0)
+ return -ENOMEM;
+ } else {
+ char a[INET6_ADDRSTRLEN];
+
+ if (asprintf(&p,
+ "[%s]:%u",
+ inet_ntop(AF_INET6, &sa->in6.sin6_addr, a, sizeof(a)),
+ ntohs(sa->in6.sin6_port)) < 0)
+ return -ENOMEM;
+ }
+
+ break;
+ }
+
+ case AF_UNIX:
+ if (salen <= offsetof(struct sockaddr_un, sun_path)) {
+ p = strdup("<unnamed>");
+ if (!p)
+ return -ENOMEM;
+
+ } else if (sa->un.sun_path[0] == 0) {
+ /* abstract */
+
+ /* FIXME: We assume we can print the
+ * socket path here and that it hasn't
+ * more than one NUL byte. That is
+ * actually an invalid assumption */
+
+ p = new(char, sizeof(sa->un.sun_path)+1);
+ if (!p)
+ return -ENOMEM;
+
+ p[0] = '@';
+ memcpy(p+1, sa->un.sun_path+1, sizeof(sa->un.sun_path)-1);
+ p[sizeof(sa->un.sun_path)] = 0;
+
+ } else {
+ p = strndup(sa->un.sun_path, sizeof(sa->un.sun_path));
+ if (!ret)
+ return -ENOMEM;
+ }
+
+ break;
+
+ default:
+ return -ENOTSUP;
+ }
+
+
+ *ret = p;
+ return 0;
+}
+
+int getpeername_pretty(int fd, char **ret) {
+ union sockaddr_union sa;
+ socklen_t salen;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ salen = sizeof(sa);
+ if (getpeername(fd, &sa.sa, &salen) < 0)
+ return -errno;
+
+ if (sa.sa.sa_family == AF_UNIX) {
+ struct ucred ucred;
+
+ /* UNIX connection sockets are anonymous, so let's use
+ * PID/UID as pretty credentials instead */
+
+ salen = sizeof(ucred);
+ if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &salen) < 0)
+ return -errno;
+
+ if (asprintf(ret, "PID %lu/UID %lu", (unsigned long) ucred.pid, (unsigned long) ucred.pid) < 0)
+ return -ENOMEM;
+
+ return 0;
+ }
+
+ /* For remote sockets we translate IPv6 addresses back to IPv4
+ * if applicable, since that's nicer. */
+
+ return sockaddr_pretty(&sa.sa, salen, true, ret);
+}
+
+int getsockname_pretty(int fd, char **ret) {
+ union sockaddr_union sa;
+ socklen_t salen;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ salen = sizeof(sa);
+ if (getsockname(fd, &sa.sa, &salen) < 0)
+ return -errno;
+
+ /* For local sockets we do not translate IPv6 addresses back
+ * to IPv6 if applicable, since this is usually used for
+ * listening sockets where the difference between IPv4 and
+ * IPv6 matters. */
+
+ return sockaddr_pretty(&sa.sa, salen, false, ret);
+}
+