Add gethostbyname and gethostbyaddr (#200)

gethostbyname, gethostbyaddr follow simple implementations: they
internally call getaddrinfo and getnameinfo respectively, and fill out
the minimum details. remaining functions are stubs.

libc/dns/ent.h

@@ -0,0 +1,27 @@
+#ifndef COSMOPOLITAN_LIBC_DNS_ENT_H_
+#define COSMOPOLITAN_LIBC_DNS_ENT_H_
+#include "libc/dns/dns.h"
+
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+extern int h_errno;
+
+struct hostent {
+  char *h_name;       /* official name of host */
+  char **h_aliases;   /* alias list */
+  int h_addrtype;     /* host address type */
+  int h_length;       /* length of address */
+  char **h_addr_list; /* list of addresses */
+};
+#define h_addr h_addr_list[0]
+
+struct hostent *gethostent(void);
+struct hostent *gethostbyname(const char *);
+struct hostent *gethostbyaddr(const void *, socklen_t, int);
+void sethostent(int);
+void endhostent(void);
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_DNS_ENT_H_ */

libc/dns/gethostbyaddr.c

@@ -0,0 +1,70 @@
+/*-*- 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│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ This is free and unencumbered software released into the public domain.      │
+│                                                                              │
+│ Anyone is free to copy, modify, publish, use, compile, sell, or              │
+│ distribute this software, either in source code form or as a compiled        │
+│ binary, for any purpose, commercial or non-commercial, and by any            │
+│ means.                                                                       │
+│                                                                              │
+│ In jurisdictions that recognize copyright laws, the author or authors        │
+│ of this software dedicate any and all copyright interest in the              │
+│ software to the public domain. We make this dedication for the benefit       │
+│ of the public at large and to the detriment of our heirs and                 │
+│ successors. We intend this dedication to be an overt act of                  │
+│ relinquishment in perpetuity of all present and future rights to this        │
+│ software under copyright law.                                                │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,              │
+│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF           │
+│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.       │
+│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR            │
+│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        │
+│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR        │
+│ OTHER DEALINGS IN THE SOFTWARE.                                              │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dns/ent.h"
+#include "libc/mem/mem.h"
+#include "libc/sysv/consts/af.h"
+
+struct hostent *gethostbyaddr(const void *s_addr, socklen_t len, int type) {
+  static struct hostent *ptr1, he1;
+  struct sockaddr_in addr;
+  char name[DNS_NAME_MAX + 1];
+
+  if (!ptr1) {
+    he1.h_name = NULL;
+
+    he1.h_aliases = (char **)malloc(sizeof(char *) * 1);
+    if (!he1.h_aliases) return NULL;
+    he1.h_aliases[0] = NULL;
+
+    he1.h_addrtype = AF_INET;
+    he1.h_length = 4;
+    he1.h_addr_list = (char **)malloc(sizeof(char *) * 2);
+    if (!he1.h_addr_list) return NULL;
+
+    he1.h_addr_list[0] = (char *)malloc(sizeof(uint32_t));
+    if (!he1.h_addr_list[0]) return NULL;
+    he1.h_addr_list[1] = NULL;
+
+    ptr1 = &he1;
+  }
+
+  if (type != AF_INET || len != sizeof(uint32_t)) return NULL;
+  addr.sin_family = AF_INET;
+  addr.sin_port = 0;
+  addr.sin_addr.s_addr = *(uint32_t *)(s_addr);
+
+  if (getnameinfo((struct sockaddr *)&addr, sizeof(addr), name, sizeof(name),
+                  NULL, 0, 0))
+    return NULL;
+
+  if (ptr1->h_name) free(ptr1->h_name);
+  ptr1->h_name = strdup(name);
+  *((uint32_t *)ptr1->h_addr_list[0]) = (addr.sin_addr.s_addr);
+
+  return ptr1;
+}

libc/dns/gethostbyname.c

@@ -0,0 +1,69 @@
+/*-*- 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│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ This is free and unencumbered software released into the public domain.      │
+│                                                                              │
+│ Anyone is free to copy, modify, publish, use, compile, sell, or              │
+│ distribute this software, either in source code form or as a compiled        │
+│ binary, for any purpose, commercial or non-commercial, and by any            │
+│ means.                                                                       │
+│                                                                              │
+│ In jurisdictions that recognize copyright laws, the author or authors        │
+│ of this software dedicate any and all copyright interest in the              │
+│ software to the public domain. We make this dedication for the benefit       │
+│ of the public at large and to the detriment of our heirs and                 │
+│ successors. We intend this dedication to be an overt act of                  │
+│ relinquishment in perpetuity of all present and future rights to this        │
+│ software under copyright law.                                                │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,              │
+│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF           │
+│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.       │
+│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR            │
+│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        │
+│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR        │
+│ OTHER DEALINGS IN THE SOFTWARE.                                              │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dns/ent.h"
+#include "libc/mem/mem.h"
+#include "libc/sysv/consts/af.h"
+
+struct hostent *gethostbyname(const char *name) {
+  static struct hostent *ptr0, he0;
+  struct addrinfo *result = NULL;
+
+  if (!ptr0) {
+    he0.h_name = NULL;
+
+    he0.h_aliases = (char **)malloc(sizeof(char *) * 1);
+    if (!he0.h_aliases) return NULL;
+    he0.h_aliases[0] = NULL;
+
+    he0.h_addrtype = AF_INET;
+    he0.h_length = 4;
+    he0.h_addr_list = (char **)malloc(sizeof(char *) * 2);
+    if (!he0.h_addr_list) return NULL;
+
+    he0.h_addr_list[0] = (char *)malloc(sizeof(uint32_t));
+    if (!he0.h_addr_list[0]) return NULL;
+    he0.h_addr_list[1] = NULL;
+
+    ptr0 = &he0;
+  }
+
+  if (getaddrinfo(name, NULL, NULL, &result) || result == NULL) return NULL;
+
+  if (ptr0->h_name) free(ptr0->h_name);
+  if (result->ai_canonname) {
+    ptr0->h_name = strdup(result->ai_canonname);
+  } else {
+    ptr0->h_name = strdup(name);
+  }
+
+  *((uint32_t *)ptr0->h_addr_list[0]) = (result->ai_addr4->sin_addr.s_addr);
+  /* TODO: if result has ai_next, fit multiple entries for h_addr_list */
+
+  freeaddrinfo(result);
+  return ptr0;
+}

libc/dns/herror.c

@@ -0,0 +1,37 @@
+/*-*- 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│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ This is free and unencumbered software released into the public domain.      │
+│                                                                              │
+│ Anyone is free to copy, modify, publish, use, compile, sell, or              │
+│ distribute this software, either in source code form or as a compiled        │
+│ binary, for any purpose, commercial or non-commercial, and by any            │
+│ means.                                                                       │
+│                                                                              │
+│ In jurisdictions that recognize copyright laws, the author or authors        │
+│ of this software dedicate any and all copyright interest in the              │
+│ software to the public domain. We make this dedication for the benefit       │
+│ of the public at large and to the detriment of our heirs and                 │
+│ successors. We intend this dedication to be an overt act of                  │
+│ relinquishment in perpetuity of all present and future rights to this        │
+│ software under copyright law.                                                │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,              │
+│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF           │
+│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.       │
+│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR            │
+│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        │
+│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR        │
+│ OTHER DEALINGS IN THE SOFTWARE.                                              │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dns/ent.h"
+
+int h_errno = 0;
+
+void herror(const char *s) {
+}
+
+const char *hstrerror(int err) {
+  return "unknown";
+}

libc/dns/hostent.c

@@ -0,0 +1,38 @@
+/*-*- 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│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ This is free and unencumbered software released into the public domain.      │
+│                                                                              │
+│ Anyone is free to copy, modify, publish, use, compile, sell, or              │
+│ distribute this software, either in source code form or as a compiled        │
+│ binary, for any purpose, commercial or non-commercial, and by any            │
+│ means.                                                                       │
+│                                                                              │
+│ In jurisdictions that recognize copyright laws, the author or authors        │
+│ of this software dedicate any and all copyright interest in the              │
+│ software to the public domain. We make this dedication for the benefit       │
+│ of the public at large and to the detriment of our heirs and                 │
+│ successors. We intend this dedication to be an overt act of                  │
+│ relinquishment in perpetuity of all present and future rights to this        │
+│ software under copyright law.                                                │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,              │
+│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF           │
+│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.       │
+│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR            │
+│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        │
+│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR        │
+│ OTHER DEALINGS IN THE SOFTWARE.                                              │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/dns/ent.h"
+
+struct hostent *gethostent(void) {
+  return NULL;
+}
+
+void sethostent(int stayopen) {
+}
+
+void endhostent(void) {
+}