1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at http://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 ***************************************************************************/ 22 23#include "setup.h" 24 25#include <string.h> 26#include <errno.h> 27 28#ifdef HAVE_SYS_SOCKET_H 29#include <sys/socket.h> 30#endif 31#ifdef HAVE_NETINET_IN_H 32#include <netinet/in.h> 33#endif 34#ifdef HAVE_NETDB_H 35#include <netdb.h> 36#endif 37#ifdef HAVE_ARPA_INET_H 38#include <arpa/inet.h> 39#endif 40#ifdef HAVE_STDLIB_H 41#include <stdlib.h> /* required for free() prototypes */ 42#endif 43#ifdef HAVE_UNISTD_H 44#include <unistd.h> /* for the close() proto */ 45#endif 46#ifdef __VMS 47#include <in.h> 48#include <inet.h> 49#include <stdlib.h> 50#endif 51 52#ifdef HAVE_PROCESS_H 53#include <process.h> 54#endif 55 56#include "urldata.h" 57#include "sendf.h" 58#include "hostip.h" 59#include "hash.h" 60#include "share.h" 61#include "strerror.h" 62#include "url.h" 63#include "inet_pton.h" 64 65#define _MPRINTF_REPLACE /* use our functions only */ 66#include <curl/mprintf.h> 67 68#include "curl_memory.h" 69/* The last #include file should be: */ 70#include "memdebug.h" 71 72/*********************************************************************** 73 * Only for plain-ipv4 builds 74 **********************************************************************/ 75#ifdef CURLRES_IPV4 /* plain ipv4 code coming up */ 76/* 77 * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've 78 * been set and returns TRUE if they are OK. 79 */ 80bool Curl_ipvalid(struct connectdata *conn) 81{ 82 if(conn->ip_version == CURL_IPRESOLVE_V6) 83 /* an ipv6 address was requested and we can't get/use one */ 84 return FALSE; 85 86 return TRUE; /* OK, proceed */ 87} 88 89#ifdef CURLRES_SYNCH 90 91/* 92 * Curl_getaddrinfo() - the ipv4 synchronous version. 93 * 94 * The original code to this function was from the Dancer source code, written 95 * by Bjorn Reese, it has since been patched and modified considerably. 96 * 97 * gethostbyname_r() is the thread-safe version of the gethostbyname() 98 * function. When we build for plain IPv4, we attempt to use this 99 * function. There are _three_ different gethostbyname_r() versions, and we 100 * detect which one this platform supports in the configure script and set up 101 * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or 102 * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME 103 * has the corresponding rules. This is primarily on *nix. Note that some unix 104 * flavours have thread-safe versions of the plain gethostbyname() etc. 105 * 106 */ 107Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, 108 const char *hostname, 109 int port, 110 int *waitp) 111{ 112 Curl_addrinfo *ai = NULL; 113 114#ifdef CURL_DISABLE_VERBOSE_STRINGS 115 (void)conn; 116#endif 117 118 *waitp = 0; /* synchronous response only */ 119 120 ai = Curl_ipv4_resolve_r(hostname, port); 121 if(!ai) 122 infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname); 123 124 return ai; 125} 126#endif /* CURLRES_SYNCH */ 127#endif /* CURLRES_IPV4 */ 128 129/* 130 * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function. 131 * 132 * This is used for both synchronous and asynchronous resolver builds, 133 * implying that only threadsafe code and function calls may be used. 134 * 135 */ 136Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, 137 int port) 138{ 139#if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3) 140 int res; 141#endif 142 Curl_addrinfo *ai = NULL; 143 struct hostent *h = NULL; 144 struct in_addr in; 145 struct hostent *buf = NULL; 146 147 if(Curl_inet_pton(AF_INET, hostname, &in) > 0) 148 /* This is a dotted IP address 123.123.123.123-style */ 149 return Curl_ip2addr(AF_INET, &in, hostname, port); 150 151#if defined(HAVE_GETADDRINFO_THREADSAFE) 152 else { 153 struct addrinfo hints; 154 char sbuf[NI_MAXSERV]; 155 char *sbufptr = NULL; 156 157 memset(&hints, 0, sizeof(hints)); 158 hints.ai_family = PF_INET; 159 hints.ai_socktype = SOCK_STREAM; 160 if(port) { 161 snprintf(sbuf, sizeof(sbuf), "%d", port); 162 sbufptr = sbuf; 163 } 164 165 (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai); 166 167#elif defined(HAVE_GETHOSTBYNAME_R) 168 /* 169 * gethostbyname_r() is the preferred resolve function for many platforms. 170 * Since there are three different versions of it, the following code is 171 * somewhat #ifdef-ridden. 172 */ 173 else { 174 int h_errnop; 175 176 buf = calloc(1, CURL_HOSTENT_SIZE); 177 if(!buf) 178 return NULL; /* major failure */ 179 /* 180 * The clearing of the buffer is a workaround for a gethostbyname_r bug in 181 * qnx nto and it is also _required_ for some of these functions on some 182 * platforms. 183 */ 184 185#if defined(HAVE_GETHOSTBYNAME_R_5) 186 /* Solaris, IRIX and more */ 187 h = gethostbyname_r(hostname, 188 (struct hostent *)buf, 189 (char *)buf + sizeof(struct hostent), 190 CURL_HOSTENT_SIZE - sizeof(struct hostent), 191 &h_errnop); 192 193 /* If the buffer is too small, it returns NULL and sets errno to 194 * ERANGE. The errno is thread safe if this is compiled with 195 * -D_REENTRANT as then the 'errno' variable is a macro defined to get 196 * used properly for threads. 197 */ 198 199 if(h) { 200 ; 201 } 202 else 203#elif defined(HAVE_GETHOSTBYNAME_R_6) 204 /* Linux */ 205 206 (void)gethostbyname_r(hostname, 207 (struct hostent *)buf, 208 (char *)buf + sizeof(struct hostent), 209 CURL_HOSTENT_SIZE - sizeof(struct hostent), 210 &h, /* DIFFERENCE */ 211 &h_errnop); 212 /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a 213 * sudden this function returns EAGAIN if the given buffer size is too 214 * small. Previous versions are known to return ERANGE for the same 215 * problem. 216 * 217 * This wouldn't be such a big problem if older versions wouldn't 218 * sometimes return EAGAIN on a common failure case. Alas, we can't 219 * assume that EAGAIN *or* ERANGE means ERANGE for any given version of 220 * glibc. 221 * 222 * For now, we do that and thus we may call the function repeatedly and 223 * fail for older glibc versions that return EAGAIN, until we run out of 224 * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). 225 * 226 * If anyone has a better fix, please tell us! 227 * 228 * ------------------------------------------------------------------- 229 * 230 * On October 23rd 2003, Dan C dug up more details on the mysteries of 231 * gethostbyname_r() in glibc: 232 * 233 * In glibc 2.2.5 the interface is different (this has also been 234 * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't 235 * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 236 * (shipped/upgraded by Redhat 7.2) don't show this behavior! 237 * 238 * In this "buggy" version, the return code is -1 on error and 'errno' 239 * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a 240 * thread-safe variable. 241 */ 242 243 if(!h) /* failure */ 244#elif defined(HAVE_GETHOSTBYNAME_R_3) 245 /* AIX, Digital Unix/Tru64, HPUX 10, more? */ 246 247 /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of 248 * the plain fact that it does not return unique full buffers on each 249 * call, but instead several of the pointers in the hostent structs will 250 * point to the same actual data! This have the unfortunate down-side that 251 * our caching system breaks down horribly. Luckily for us though, AIX 4.3 252 * and more recent versions have a "completely thread-safe"[*] libc where 253 * all the data is stored in thread-specific memory areas making calls to 254 * the plain old gethostbyname() work fine even for multi-threaded 255 * programs. 256 * 257 * This AIX 4.3 or later detection is all made in the configure script. 258 * 259 * Troels Walsted Hansen helped us work this out on March 3rd, 2003. 260 * 261 * [*] = much later we've found out that it isn't at all "completely 262 * thread-safe", but at least the gethostbyname() function is. 263 */ 264 265 if(CURL_HOSTENT_SIZE >= 266 (sizeof(struct hostent)+sizeof(struct hostent_data))) { 267 268 /* August 22nd, 2000: Albert Chin-A-Young brought an updated version 269 * that should work! September 20: Richard Prescott worked on the buffer 270 * size dilemma. 271 */ 272 273 res = gethostbyname_r(hostname, 274 (struct hostent *)buf, 275 (struct hostent_data *)((char *)buf + 276 sizeof(struct hostent))); 277 h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */ 278 } 279 else 280 res = -1; /* failure, too smallish buffer size */ 281 282 if(!res) { /* success */ 283 284 h = buf; /* result expected in h */ 285 286 /* This is the worst kind of the different gethostbyname_r() interfaces. 287 * Since we don't know how big buffer this particular lookup required, 288 * we can't realloc down the huge alloc without doing closer analysis of 289 * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every 290 * name lookup. Fixing this would require an extra malloc() and then 291 * calling Curl_addrinfo_copy() that subsequent realloc()s down the new 292 * memory area to the actually used amount. 293 */ 294 } 295 else 296#endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */ 297 { 298 h = NULL; /* set return code to NULL */ 299 free(buf); 300 } 301#else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 302 /* 303 * Here is code for platforms that don't have a thread safe 304 * getaddrinfo() nor gethostbyname_r() function or for which 305 * gethostbyname() is the preferred one. 306 */ 307 else { 308 h = gethostbyname((void*)hostname); 309#endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ 310 } 311 312 if(h) { 313 ai = Curl_he2ai(h, port); 314 315 if(buf) /* used a *_r() function */ 316 free(buf); 317 } 318 319 return ai; 320} 321