Use DNS implementation from Musl Libc

Now that our socket system call polyfills are good enough to support
Musl's DNS library we should be using that rather than the barebones
domain name system implementation we rolled on our own. There's many
benefits to making this change. So many, that I myself wouldn't feel
qualified to enumerate them all. The Musl DNS code had to be changed
in order to support Windows of course, which looks very solid so far

Author: jart

Makefile

@@ -198,9 +198,9 @@ include third_party/nsync/mem/BUILD.mk		# │  You can now use stdio
 include libc/proc/BUILD.mk			# │  You can now use threads
 include libc/dlopen/BUILD.mk			# │  You can now use processes
 include libc/thread/BUILD.mk			# │  You can finally call malloc()
-include tool/hello/BUILD.mk			# │
 include third_party/zlib/BUILD.mk		# │
 include libc/stdio/BUILD.mk			# │
+include tool/hello/BUILD.mk			# │
 include libc/time/BUILD.mk			# │
 include net/BUILD.mk				# │
 include third_party/vqsort/BUILD.mk		# │
@@ -213,9 +213,8 @@ include third_party/intel/BUILD.mk		# │
 include third_party/aarch64/BUILD.mk		# │
 include libc/BUILD.mk				#─┘
 include libc/sock/BUILD.mk			#─┐
-include libc/dns/BUILD.mk			# ├──ONLINE RUNTIME
-include net/http/BUILD.mk			# │  You can communicate with the network
-include third_party/musl/BUILD.mk		# │
+include net/http/BUILD.mk			# ├──ONLINE RUNTIME
+include third_party/musl/BUILD.mk		# │  You can communicate with the network
 include libc/x/BUILD.mk				# │
 include dsp/scale/BUILD.mk			# │
 include dsp/mpeg/BUILD.mk			# │
@@ -297,7 +296,6 @@ include test/libc/calls/BUILD.mk
 include test/libc/x/BUILD.mk
 include test/libc/xed/BUILD.mk
 include test/libc/fmt/BUILD.mk
-include test/libc/dns/BUILD.mk
 include test/libc/time/BUILD.mk
 include test/libc/proc/BUILD.mk
 include test/libc/stdio/BUILD.mk
@@ -373,7 +371,6 @@ loc: o/$(MODE)/tool/build/summy.com
 COSMOPOLITAN_OBJECTS =			\
 	TOOL_ARGS			\
 	NET_HTTP			\
-	LIBC_DNS			\
 	LIBC_SOCK			\
 	LIBC_NT_WS2_32			\
 	LIBC_NT_IPHLPAPI		\
@@ -424,7 +421,6 @@ COSMOPOLITAN_H_PKGS =			\
 	APE				\
 	LIBC				\
 	LIBC_CALLS			\
-	LIBC_DNS			\
 	LIBC_ELF			\
 	LIBC_FMT			\
 	LIBC_DLOPEN			\

dsp/mpeg/buffer.h

@@ -3,8 +3,6 @@
 #include "dsp/mpeg/mpeg.h"
 COSMOPOLITAN_C_START_
 
-struct FILE;
-
 enum plm_buffer_mode {
   PLM_BUFFER_MODE_FILE,
   PLM_BUFFER_MODE_FIXED_MEM,
@@ -17,7 +15,7 @@ typedef struct plm_buffer_t {
   unsigned length;
   int free_when_done;
   int close_when_done;
-  struct FILE *fh;
+  FILE *fh;
   plm_buffer_load_callback load_callback;
   void *load_callback_user_data;
   unsigned char *bytes;

dsp/mpeg/mpeg.h

@@ -1,9 +1,8 @@
 #ifndef COSMOPOLITAN_DSP_MPEG_MPEG_H_
 #define COSMOPOLITAN_DSP_MPEG_MPEG_H_
+#include "libc/stdio/stdio.h"
 COSMOPOLITAN_C_START_
 
-struct FILE;
-
 typedef struct plm_t plm_t;
 typedef struct plm_buffer_t plm_buffer_t;
 typedef struct plm_demux_t plm_demux_t;
@@ -112,7 +111,7 @@ plm_t *plm_create_with_filename(const char *filename);
  * to let plmpeg call fclose() on the handle when plm_destroy() is
  * called.
  */
-plm_t *plm_create_with_file(struct FILE *fh, int close_when_done);
+plm_t *plm_create_with_file(FILE *fh, int close_when_done);
 
 /**
  * Create a plmpeg instance with pointer to memory as source. This assumes the
@@ -257,7 +256,7 @@ plm_buffer_t *plm_buffer_create_with_filename(const char *filename);
  * to let plmpeg call fclose() on the handle when plm_destroy() is
  * called.
  */
-plm_buffer_t *plm_buffer_create_with_file(struct FILE *fh, int close_when_done);
+plm_buffer_t *plm_buffer_create_with_file(FILE *fh, int close_when_done);
 
 /**
  * Create a buffer instance with a pointer to memory as source. This assumes

dsp/tty/tty.h

@@ -5,7 +5,6 @@
 
 COSMOPOLITAN_C_START_
 
-struct FILE;
 struct termios;
 
 struct TtyIdent {

examples/BUILD.mk

@@ -44,7 +44,6 @@ EXAMPLES_DIRECTDEPS =								\
 	DSP_TTY									\
 	LIBC_CALLS								\
 	LIBC_DLOPEN								\
-	LIBC_DNS								\
 	LIBC_FMT								\
 	LIBC_INTRIN								\
 	LIBC_IRQ								\

examples/nc.c

@@ -8,7 +8,6 @@
 ╚─────────────────────────────────────────────────────────────────*/
 #endif
 #include "libc/calls/calls.h"
-#include "libc/dns/dns.h"
 #include "libc/fmt/conv.h"
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
@@ -26,6 +25,7 @@
 #include "libc/sysv/consts/sock.h"
 #include "libc/sysv/consts/sol.h"
 #include "third_party/getopt/getopt.internal.h"
+#include "third_party/musl/netdb.h"
 
 /**
  * @fileoverview netcat clone
@@ -60,9 +60,7 @@ int main(int argc, char *argv[]) {
         halfclose = false;
         break;
       case 'h':
-        fputs("Usage: ", stdout);
-        fputs(argv[0], stdout);
-        fputs(" [-hH] IP PORT\n", stdout);
+        tinyprint(1, "Usage: ", argv[0], " [-hH] IP PORT\n", NULL);
         exit(0);
       default:
         fprintf(stderr, "bad option %d\n", opt);
@@ -76,17 +74,9 @@ int main(int argc, char *argv[]) {
   host = argv[optind + 0];
   port = argv[optind + 1];
 
-  switch ((rc = getaddrinfo(host, port, &hint, &ai))) {
-    case EAI_SUCCESS:
-      break;
-    case EAI_SYSTEM:
-      perror("getaddrinfo");
-      exit(1);
-    default:
-      fputs("EAI_", stderr);
-      fputs(gai_strerror(rc), stderr);
-      fputs("\n", stderr);
-      exit(1);
+  if ((rc = getaddrinfo(host, port, &hint, &ai))) {
+    tinyprint(2, host, ": ", gai_strerror(rc), "\n", NULL);
+    exit(1);
   }
 
   if ((sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol)) == -1) {
@@ -95,12 +85,12 @@ int main(int argc, char *argv[]) {
   }
 
   if (setsockopt(sock, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger)) == -1) {
-    perror("setsockopt(SO_LINGER)");
+    perror("SO_LINGER");
     exit(1);
   }
 
   if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
-    perror("connect");
+    perror(host);
     exit(1);
   }
 

examples/whois.c

@@ -30,12 +30,13 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/calls/weirdtypes.h"
-#include "libc/dns/dns.h"
 #include "libc/errno.h"
 #include "libc/log/bsd.h"
 #include "libc/mem/mem.h"
 #include "libc/runtime/runtime.h"
+#include "libc/sock/sock.h"
 #include "libc/sock/struct/pollfd.h"
+#include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/af.h"
 #include "libc/sysv/consts/ex.h"
@@ -44,6 +45,7 @@
 #include "libc/sysv/consts/poll.h"
 #include "libc/sysv/consts/sock.h"
 #include "third_party/getopt/getopt.internal.h"
+#include "third_party/musl/netdb.h"
 // clang-format off
 
 asm(".ident\t\"\\n\\n\

libc/BUILD.mk

@@ -276,7 +276,6 @@ LIBC_FILES := $(wildcard libc/*)
 o/$(MODE)/libc:	o/$(MODE)/libc/calls		\
 		o/$(MODE)/libc/crt		\
 		o/$(MODE)/libc/dlopen		\
-		o/$(MODE)/libc/dns		\
 		o/$(MODE)/libc/elf		\
 		o/$(MODE)/libc/fmt		\
 		o/$(MODE)/libc/intrin		\

libc/calls/h_errno.c renamed to libc/calls/gethoststxtpath.c

@@ -1,7 +1,7 @@
 /*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
 │ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
 ╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
 │                                                                              │
 │ Permission to use, copy, modify, and/or distribute this software for         │
 │ any purpose with or without fee is hereby granted, provided that the         │
@@ -16,11 +16,13 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/dns/ent.h"
+#include "libc/calls/sysdir.internal.h"
+#include "libc/dce.h"
 
-// error number global for gethostbyname*(), gethostbyaddr*(), etc.
-static _Thread_local int __h_errno;
-
-errno_t *__h_errno_location(void) {
-  return &__h_errno;
+const char *GetHostsTxtPath(char *path, size_t size) {
+  if (!IsWindows()) {
+    return "/etc/hosts";
+  } else {
+    return GetSystemDirectoryPath(path, "drivers\\etc\\hosts", size);
+  }
 }

libc/dns/freeaddrinfo.c renamed to libc/calls/getprotocolstxtpath.c

@@ -1,7 +1,7 @@
 /*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
 │ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
 ╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
 │                                                                              │
 │ Permission to use, copy, modify, and/or distribute this software for         │
 │ any purpose with or without fee is hereby granted, provided that the         │
@@ -16,18 +16,13 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/dns/dns.h"
-#include "libc/mem/mem.h"
+#include "libc/calls/sysdir.internal.h"
+#include "libc/dce.h"
 
-/**
- * Frees addresses returned by getaddrinfo().
- */
-void freeaddrinfo(struct addrinfo *ai) {
-  struct addrinfo *next;
-  while (ai) {
-    /* we assume ai_addr and ai_canonname are shoehorned */
-    next = ai->ai_next;
-    free(ai);
-    ai = next;
+const char *GetProtocolsTxtPath(char *buf, size_t size) {
+  if (!IsWindows()) {
+    return "/etc/protocols";
+  } else {
+    return GetSystemDirectoryPath(buf, "drivers\\etc\\protocol", size);
   }
 }