Add a "fork" of musl as //fusl.

fusl/src/network/getnameinfo.c

+#include <netdb.h>
+#include <limits.h>
+#include <string.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <ctype.h>
+#include "lookup.h"
+#include "stdio_impl.h"
+
+int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *);
+int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int);
+int __res_mkquery(int, const char *, int, int, const unsigned char *, int, const unsigned char*, unsigned char *, int);
+int __res_send(const unsigned char *, int, unsigned char *, int);
+
+#define PTR_MAX (64 + sizeof ".in-addr.arpa")
+#define RR_PTR 12
+
+static char *itoa(char *p, unsigned x) {
+        p += 3*sizeof(int);
+        *--p = 0;
+        do {
+                *--p = '0' + x % 10;
+                x /= 10;
+        } while (x);
+        return p;
+}
+
+static void mkptr4(char *s, const unsigned char *ip)
+{
+        sprintf(s, "%d.%d.%d.%d.in-addr.arpa",
+                ip[3], ip[2], ip[1], ip[0]);
+}
+
+static void mkptr6(char *s, const unsigned char *ip)
+{
+        static const char xdigits[] = "0123456789abcdef";
+        int i;
+        for (i=15; i>=0; i--) {
+                *s++ = xdigits[ip[i]&15]; *s++ = '.';
+                *s++ = xdigits[ip[i]>>4]; *s++ = '.';
+        }
+        strcpy(s, "ip6.arpa");
+}
+
+static void reverse_hosts(char *buf, const unsigned char *a, unsigned scopeid, int family)
+{
+        char line[512], *p, *z;
+        unsigned char _buf[1032], atmp[16];
+        struct address iplit;
+        FILE _f, *f = __fopen_rb_ca("/etc/hosts", &_f, _buf, sizeof _buf);
+        if (!f) return;
+        if (family == AF_INET) {
+                memcpy(atmp+12, a, 4);
+                memcpy(atmp, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+                a = atmp;
+        }
+        while (fgets(line, sizeof line, f)) {
+                if ((p=strchr(line, '#'))) *p++='\n', *p=0;
+
+                for (p=line; *p && !isspace(*p); p++);
+                *p++ = 0;
+                if (__lookup_ipliteral(&iplit, line, AF_UNSPEC)<=0)
+                        continue;
+
+                if (iplit.family == AF_INET) {
+                        memcpy(iplit.addr+12, iplit.addr, 4);
+                        memcpy(iplit.addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+                        iplit.scopeid = 0;
+                }
+
+                if (memcmp(a, iplit.addr, 16) || iplit.scopeid != scopeid)
+                        continue;
+                        
+                for (; *p && isspace(*p); p++);
+                for (z=p; *z && !isspace(*z); z++);
+                *z = 0;
+                if (z-p < 256) {
+                        memcpy(buf, p, z-p+1);
+                        break;
+                }
+        }
+        __fclose_ca(f);
+}
+
+static void reverse_services(char *buf, int port, int dgram)
+{
+        unsigned long svport;
+        char line[128], *p, *z;
+        unsigned char _buf[1032];
+        FILE _f, *f = __fopen_rb_ca("/etc/services", &_f, _buf, sizeof _buf);
+        if (!f) return;
+        while (fgets(line, sizeof line, f)) {
+                if ((p=strchr(line, '#'))) *p++='\n', *p=0;
+
+                for (p=line; *p && !isspace(*p); p++);
+                if (!*p) continue;
+                *p++ = 0;
+                svport = strtoul(p, &z, 10);
+
+                if (svport != port || z==p) continue;
+                if (dgram && strncmp(z, "/udp", 4)) continue;
+                if (!dgram && strncmp(z, "/tcp", 4)) continue;
+                if (p-line > 32) continue;
+
+                memcpy(buf, line, p-line);
+                break;
+        }
+        __fclose_ca(f);
+}
+
+static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet)
+{
+        if (rr != RR_PTR) return 0;
+        if (__dn_expand(packet, (const unsigned char *)packet + 512,
+            data, c, 256) <= 0)
+                *(char *)c = 0;
+        return 0;
+        
+}
+
+int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
+        char *restrict node, socklen_t nodelen,
+        char *restrict serv, socklen_t servlen,
+        int flags)
+{
+        char ptr[PTR_MAX];
+        char buf[256], num[3*sizeof(int)+1];
+        int af = sa->sa_family;
+        unsigned char *a;
+        unsigned scopeid;
+
+        switch (af) {
+        case AF_INET:
+                a = (void *)&((struct sockaddr_in *)sa)->sin_addr;
+                if (sl < sizeof(struct sockaddr_in)) return EAI_FAMILY;
+                mkptr4(ptr, a);
+                scopeid = 0;
+                break;
+        case AF_INET6:
+                a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr;
+                if (sl < sizeof(struct sockaddr_in6)) return EAI_FAMILY;
+                if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12))
+                        mkptr6(ptr, a);
+                else
+                        mkptr4(ptr, a+12);
+                scopeid = ((struct sockaddr_in6 *)sa)->sin6_scope_id;
+                break;
+        default:
+                return EAI_FAMILY;
+        }
+
+        if (node && nodelen) {
+                buf[0] = 0;
+                if (!(flags & NI_NUMERICHOST)) {
+                        reverse_hosts(buf, a, scopeid, af);
+                }
+                if (!*buf && !(flags & NI_NUMERICHOST)) {
+                        unsigned char query[18+PTR_MAX], reply[512];
+                        int qlen = __res_mkquery(0, ptr, 1, RR_PTR,
+                                0, 0, 0, query, sizeof query);
+                        int rlen = __res_send(query, qlen, reply, sizeof reply);
+                        buf[0] = 0;
+                        if (rlen > 0)
+                                __dns_parse(reply, rlen, dns_parse_callback, buf);
+                }
+                if (!*buf) {
+                        if (flags & NI_NAMEREQD) return EAI_NONAME;
+                        inet_ntop(af, a, buf, sizeof buf);
+                        if (scopeid) {
+                                char *p = 0, tmp[IF_NAMESIZE+1];
+                                if (!(flags & NI_NUMERICSCOPE) &&
+                                    (IN6_IS_ADDR_LINKLOCAL(a) ||
+                                     IN6_IS_ADDR_MC_LINKLOCAL(a)))
+                                        p = if_indextoname(scopeid, tmp+1);
+                                if (!p)
+                                        p = itoa(num, scopeid);
+                                *--p = '%';
+                                strcat(buf, p);
+                        }
+                }
+                if (strlen(buf) >= nodelen) return EAI_OVERFLOW;
+                strcpy(node, buf);
+        }
+
+        if (serv && servlen) {
+                char *p = buf;
+                int port = ntohs(((struct sockaddr_in *)sa)->sin_port);
+                buf[0] = 0;
+                if (!(flags & NI_NUMERICSERV))
+                        reverse_services(buf, port, flags & NI_DGRAM);
+                if (!*p)
+                        p = itoa(num, port);
+                if (strlen(p) >= servlen)
+                        return EAI_OVERFLOW;
+                strcpy(serv, p);
+        }
+
+        return 0;
+}