/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at http://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ #include "setup.h" #ifdef HAVE_SYS_SOCKET_H #include <sys/socket.h> #endif #ifdef HAVE_NETINET_IN_H #include <netinet/in.h> #endif #ifdef HAVE_NETDB_H #include <netdb.h> #endif #ifdef HAVE_ARPA_INET_H #include <arpa/inet.h> #endif #ifdef HAVE_UNISTD_H #include <unistd.h> /* for the close() proto */ #endif #ifdef __VMS #include <in.h> #include <inet.h> #endif #ifdef HAVE_PROCESS_H #include <process.h> #endif #include "urldata.h" #include "sendf.h" #include "hostip.h" #include "hash.h" #include "share.h" #include "strerror.h" #include "url.h" #include "inet_pton.h" #define _MPRINTF_REPLACE /* use our functions only */ #include <curl/mprintf.h> #include "curl_memory.h" /* The last #include file should be: */ #include "memdebug.h" /*********************************************************************** * Only for plain-ipv4 builds **********************************************************************/ #ifdef CURLRES_IPV4 /* plain ipv4 code coming up */ /* * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've * been set and returns TRUE if they are OK. */ bool Curl_ipvalid(struct connectdata *conn) { if(conn->ip_version == CURL_IPRESOLVE_V6) /* an ipv6 address was requested and we can't get/use one */ return FALSE; return TRUE; /* OK, proceed */ } #ifdef CURLRES_SYNCH /* * Curl_getaddrinfo() - the ipv4 synchronous version. * * The original code to this function was from the Dancer source code, written * by Bjorn Reese, it has since been patched and modified considerably. * * gethostbyname_r() is the thread-safe version of the gethostbyname() * function. When we build for plain IPv4, we attempt to use this * function. There are _three_ different gethostbyname_r() versions, and we * detect which one this platform supports in the configure script and set up * the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or * HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME * has the corresponding rules. This is primarily on *nix. Note that some unix * flavours have thread-safe versions of the plain gethostbyname() etc. * */ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn, const char *hostname, int port, int *waitp) { Curl_addrinfo *ai = NULL; #ifdef CURL_DISABLE_VERBOSE_STRINGS (void)conn; #endif *waitp = 0; /* synchronous response only */ ai = Curl_ipv4_resolve_r(hostname, port); if(!ai) infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname); return ai; } #endif /* CURLRES_SYNCH */ #endif /* CURLRES_IPV4 */ #if defined(CURLRES_IPV4) && !defined(CURLRES_ARES) /* * Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function. * * This is used for both synchronous and asynchronous resolver builds, * implying that only threadsafe code and function calls may be used. * */ Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, int port) { #if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3) int res; #endif Curl_addrinfo *ai = NULL; struct hostent *h = NULL; struct in_addr in; struct hostent *buf = NULL; if(Curl_inet_pton(AF_INET, hostname, &in) > 0) /* This is a dotted IP address 123.123.123.123-style */ return Curl_ip2addr(AF_INET, &in, hostname, port); #if defined(HAVE_GETADDRINFO_THREADSAFE) else { struct addrinfo hints; char sbuf[NI_MAXSERV]; char *sbufptr = NULL; memset(&hints, 0, sizeof(hints)); hints.ai_family = PF_INET; hints.ai_socktype = SOCK_STREAM; if(port) { snprintf(sbuf, sizeof(sbuf), "%d", port); sbufptr = sbuf; } (void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai); #elif defined(HAVE_GETHOSTBYNAME_R) /* * gethostbyname_r() is the preferred resolve function for many platforms. * Since there are three different versions of it, the following code is * somewhat #ifdef-ridden. */ else { int h_errnop; buf = calloc(1, CURL_HOSTENT_SIZE); if(!buf) return NULL; /* major failure */ /* * The clearing of the buffer is a workaround for a gethostbyname_r bug in * qnx nto and it is also _required_ for some of these functions on some * platforms. */ #if defined(HAVE_GETHOSTBYNAME_R_5) /* Solaris, IRIX and more */ h = gethostbyname_r(hostname, (struct hostent *)buf, (char *)buf + sizeof(struct hostent), CURL_HOSTENT_SIZE - sizeof(struct hostent), &h_errnop); /* If the buffer is too small, it returns NULL and sets errno to * ERANGE. The errno is thread safe if this is compiled with * -D_REENTRANT as then the 'errno' variable is a macro defined to get * used properly for threads. */ if(h) { ; } else #elif defined(HAVE_GETHOSTBYNAME_R_6) /* Linux */ (void)gethostbyname_r(hostname, (struct hostent *)buf, (char *)buf + sizeof(struct hostent), CURL_HOSTENT_SIZE - sizeof(struct hostent), &h, /* DIFFERENCE */ &h_errnop); /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a * sudden this function returns EAGAIN if the given buffer size is too * small. Previous versions are known to return ERANGE for the same * problem. * * This wouldn't be such a big problem if older versions wouldn't * sometimes return EAGAIN on a common failure case. Alas, we can't * assume that EAGAIN *or* ERANGE means ERANGE for any given version of * glibc. * * For now, we do that and thus we may call the function repeatedly and * fail for older glibc versions that return EAGAIN, until we run out of * buffer size (step_size grows beyond CURL_HOSTENT_SIZE). * * If anyone has a better fix, please tell us! * * ------------------------------------------------------------------- * * On October 23rd 2003, Dan C dug up more details on the mysteries of * gethostbyname_r() in glibc: * * In glibc 2.2.5 the interface is different (this has also been * discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't * explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32 * (shipped/upgraded by Redhat 7.2) don't show this behavior! * * In this "buggy" version, the return code is -1 on error and 'errno' * is set to the ERANGE or EAGAIN code. Note that 'errno' is not a * thread-safe variable. */ if(!h) /* failure */ #elif defined(HAVE_GETHOSTBYNAME_R_3) /* AIX, Digital Unix/Tru64, HPUX 10, more? */ /* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of * the plain fact that it does not return unique full buffers on each * call, but instead several of the pointers in the hostent structs will * point to the same actual data! This have the unfortunate down-side that * our caching system breaks down horribly. Luckily for us though, AIX 4.3 * and more recent versions have a "completely thread-safe"[*] libc where * all the data is stored in thread-specific memory areas making calls to * the plain old gethostbyname() work fine even for multi-threaded * programs. * * This AIX 4.3 or later detection is all made in the configure script. * * Troels Walsted Hansen helped us work this out on March 3rd, 2003. * * [*] = much later we've found out that it isn't at all "completely * thread-safe", but at least the gethostbyname() function is. */ if(CURL_HOSTENT_SIZE >= (sizeof(struct hostent)+sizeof(struct hostent_data))) { /* August 22nd, 2000: Albert Chin-A-Young brought an updated version * that should work! September 20: Richard Prescott worked on the buffer * size dilemma. */ res = gethostbyname_r(hostname, (struct hostent *)buf, (struct hostent_data *)((char *)buf + sizeof(struct hostent))); h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */ } else res = -1; /* failure, too smallish buffer size */ if(!res) { /* success */ h = buf; /* result expected in h */ /* This is the worst kind of the different gethostbyname_r() interfaces. * Since we don't know how big buffer this particular lookup required, * we can't realloc down the huge alloc without doing closer analysis of * the returned data. Thus, we always use CURL_HOSTENT_SIZE for every * name lookup. Fixing this would require an extra malloc() and then * calling Curl_addrinfo_copy() that subsequent realloc()s down the new * memory area to the actually used amount. */ } else #endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */ { h = NULL; /* set return code to NULL */ free(buf); } #else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ /* * Here is code for platforms that don't have a thread safe * getaddrinfo() nor gethostbyname_r() function or for which * gethostbyname() is the preferred one. */ else { h = gethostbyname((void*)hostname); #endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */ } if(h) { ai = Curl_he2ai(h, port); if(buf) /* used a *_r() function */ free(buf); } return ai; } #endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */