Initial import

libc/dns/getaddrinfo.c

@@ -0,0 +1,98 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/safemacros.h"
+#include "libc/conv/conv.h"
+#include "libc/dns/dns.h"
+#include "libc/dns/hoststxt.h"
+#include "libc/dns/resolvconf.h"
+#include "libc/mem/mem.h"
+#include "libc/sock/sock.h"
+#include "libc/str/str.h"
+#include "libc/calls/calls.h"
+#include "libc/sysv/errfuns.h"
+#include "libc/sysv/consts/af.h"
+#include "libc/sysv/consts/ai.h"
+#include "libc/sysv/consts/eai.h"
+#include "libc/sysv/consts/inaddr.h"
+
+/**
+ * Resolves address for internet name.
+ *
+ * @param node is either an ip string or a utf-8 hostname
+ * @param service is the port number as a string
+ * @param hints may be passed to specialize behavior (optional)
+ * @param res receives a pointer that must be freed with freeaddrinfo(),
+ *     and won't be modified if -1 is returned
+ * @return 0 on success or EAI_xxx value
+ */
+int getaddrinfo(const char *name, const char *service,
+                const struct addrinfo *hints, struct addrinfo **res) {
+  int port = 0;
+  struct addrinfo *ai;
+  if ((!name && !service) || (service && (port = parseport(service)) == -1)) {
+    return EAI_NONAME;
+  }
+  if (!name && (hints->ai_flags & AI_CANONNAME) == AI_CANONNAME) {
+    return EAI_BADFLAGS;
+  }
+  if (!(ai = newaddrinfo(port))) {
+    return EAI_MEMORY;
+  }
+  if (service) {
+    ai->ai_addr4->sin_port = htons(port);
+  }
+  if (hints) {
+    ai->ai_socktype = hints->ai_socktype;
+    ai->ai_protocol = hints->ai_protocol;
+  }
+  if (!name) {
+    ai->ai_addr4->sin_addr.s_addr =
+        (hints && (hints->ai_flags & AI_PASSIVE) == AI_PASSIVE)
+            ? INADDR_ANY
+            : INADDR_LOOPBACK;
+    return 0;
+  }
+  const char *canon;
+  if (inet_pton(AF_INET, name, &ai->ai_addr4->sin_addr.s_addr) == 1) {
+    *res = ai;
+    return 0;
+  } else if (hints && (hints->ai_flags & AI_NUMERICHOST) == AI_NUMERICHOST) {
+    freeaddrinfo(ai);
+    return EAI_NONAME;
+  } else if (resolvehoststxt(gethoststxt(), AF_INET, name, ai->ai_addr,
+                             sizeof(ai->ai_addr4), &canon) > 0) {
+    memcpy(ai->ai_canonname, canon, min(strlen(canon), DNS_NAME_MAX) + 1);
+    *res = ai;
+    return 0;
+  } else {
+    int rc = resolvedns(getresolvconf(), AF_INET, name, ai->ai_addr,
+                        sizeof(ai->ai_addr4));
+    if (rc > 0) {
+      *res = ai;
+      return 0;
+    }
+    freeaddrinfo(ai);
+    if (rc == 0) {
+      return EAI_NONAME;
+    } else {
+      return EAI_SYSTEM;
+    }
+  }
+}