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+/***************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2004, 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.
+ *
+ * $Id$
+ ***************************************************************************/
+
+#include "setup.h"
+
+#include <string.h>
+#include <errno.h>
+
+#define _REENTRANT
+
+#if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
+#include <malloc.h>
+#else
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#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_STDLIB_H
+#include <stdlib.h> /* required for free() prototypes */
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h> /* for the close() proto */
+#endif
+#ifdef VMS
+#include <in.h>
+#include <inet.h>
+#include <stdlib.h>
+#endif
+#endif
+
+#ifdef HAVE_SETJMP_H
+#include <setjmp.h>
+#endif
+
+#ifdef WIN32
+#include <process.h>
+#endif
+
+#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
+#undef in_addr_t
+#define in_addr_t unsigned long
+#endif
+
+#include "urldata.h"
+#include "sendf.h"
+#include "hostip.h"
+#include "hash.h"
+#include "share.h"
+#include "strerror.h"
+#include "url.h"
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
+#if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL)
+#include "inet_ntoa_r.h"
+#endif
+
+/* The last #include file should be: */
+#ifdef CURLDEBUG
+#include "memdebug.h"
+#endif
+
+/***********************************************************************
+ * Only for plain-ipv4 builds
+ **********************************************************************/
+#ifdef CURLRES_IPV4 /* plain ipv4 code coming up */
+
+/*
+ * This is a wrapper function for freeing name information in a protocol
+ * independent way. This takes care of using the appropriate underlying
+ * function.
+ */
+void Curl_freeaddrinfo(Curl_addrinfo *p)
+{
+ free(p); /* works fine for the ARES case too */
+}
+
+/*
+ * Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've
+ * been set and returns TRUE if they are OK.
+ */
+bool Curl_ipvalid(struct SessionHandle *data)
+{
+ if(data->set.ip_version == CURL_IPRESOLVE_V6)
+ /* an ipv6 address was requested and we can't get/use one */
+ return FALSE;
+
+ return TRUE; /* OK, proceed */
+}
+
+/*
+ * Curl_ip2addr() takes a 32bit ipv4 internet address as input parameter
+ * together with a pointer to the string version of the address, and it
+ * retruns a malloc()ed version of a hostent struct filled in correctly with
+ * information for this address/host.
+ *
+ * The input parameters ARE NOT checked for validity but they are expected
+ * to have been checked already when this is called.
+ */
+Curl_addrinfo *Curl_ip2addr(unsigned long num, char *hostname)
+{
+ struct hostent *h;
+ struct in_addr *addrentry;
+ struct namebuf {
+ struct hostent hostentry;
+ char *h_addr_list[2];
+ struct in_addr addrentry;
+ char h_name[16]; /* 123.123.123.123 = 15 letters is maximum */
+ } *buf = (struct namebuf *)malloc(sizeof(struct namebuf));
+
+ if(!buf)
+ return NULL; /* major failure */
+
+ h = &buf->hostentry;
+ h->h_addr_list = &buf->h_addr_list[0];
+ addrentry = &buf->addrentry;
+ addrentry->s_addr = num;
+ h->h_addr_list[0] = (char*)addrentry;
+ h->h_addr_list[1] = NULL;
+ h->h_addrtype = AF_INET;
+ h->h_length = sizeof(*addrentry);
+ h->h_name = &buf->h_name[0];
+ h->h_aliases = NULL;
+
+ /* Now store the dotted version of the address */
+ snprintf(h->h_name, 16, "%s", hostname);
+
+ return h;
+}
+
+#ifdef CURLRES_SYNCH /* the functions below are for synchronous resolves */
+
+/*
+ * Curl_getaddrinfo() - the ipv4 synchronous version.
+ *
+ * The original code to this function was once stolen 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,
+ char *hostname,
+ int port,
+ int *waitp)
+{
+ struct hostent *h = NULL;
+ in_addr_t in;
+ struct SessionHandle *data = conn->data;
+ (void)port; /* unused in IPv4 code */
+
+ *waitp = 0; /* don't wait, we act synchronously */
+
+ in=inet_addr(hostname);
+ if (in != CURL_INADDR_NONE)
+ /* This is a dotted IP address 123.123.123.123-style */
+ return Curl_ip2addr(in, hostname);
+
+#if 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;
+ int res=ERANGE;
+ int step_size=200;
+ int *buf = (int *)calloc(CURL_HOSTENT_SIZE, 1);
+ 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.
+ */
+
+#ifdef HAVE_GETHOSTBYNAME_R_5
+ /* Solaris, IRIX and more */
+ (void)res; /* prevent compiler warning */
+ while(!h) {
+ h = gethostbyname_r(hostname,
+ (struct hostent *)buf,
+ (char *)buf + sizeof(struct hostent),
+ step_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 || (errno != ERANGE))
+ break;
+
+ step_size+=200;
+ }
+
+#ifdef CURLDEBUG
+ infof(data, "gethostbyname_r() uses %d bytes\n", step_size);
+#endif
+
+ if(h) {
+ int offset;
+ h=(struct hostent *)realloc(buf, step_size);
+ offset=(long)h-(long)buf;
+ Curl_hostent_relocate(h, offset);
+ buf=(int *)h;
+ }
+ else
+#endif /* HAVE_GETHOSTBYNAME_R_5 */
+#ifdef HAVE_GETHOSTBYNAME_R_6
+ /* Linux */
+ do {
+ res=gethostbyname_r(hostname,
+ (struct hostent *)buf,
+ (char *)buf + sizeof(struct hostent),
+ step_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(((ERANGE == res) || (EAGAIN == res)) ||
+ ((res<0) && ((ERANGE == errno) || (EAGAIN == errno))))
+ step_size+=200;
+ else
+ break;
+ } while(step_size <= CURL_HOSTENT_SIZE);
+
+ if(!h) /* failure */
+ res=1;
+
+#ifdef CURLDEBUG
+ infof(data, "gethostbyname_r() uses %d bytes\n", step_size);
+#endif
+ if(!res) {
+ int offset;
+ h=(struct hostent *)realloc(buf, step_size);
+ offset=(long)h-(long)buf;
+ Curl_hostent_relocate(h, offset);
+ buf=(int *)h;
+ }
+ else
+#endif/* HAVE_GETHOSTBYNAME_R_6 */
+#ifdef 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= errno; /* we don't deal with this, but set it anyway */
+ }
+ else
+ res = -1; /* failure, too smallish buffer size */
+
+ if(!res) { /* success */
+
+ h = (struct hostent*)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_GETHOSTBYNAME_R_3 */
+ {
+ infof(data, "gethostbyname_r(2) failed for %s\n", hostname);
+ h = NULL; /* set return code to NULL */
+ free(buf);
+ }
+#else /* HAVE_GETHOSTBYNAME_R */
+ /*
+ * Here is code for platforms that don't have gethostbyname_r() or for
+ * which the gethostbyname() is the preferred() function.
+ */
+ else {
+ h = gethostbyname(hostname);
+ if (!h)
+ infof(data, "gethostbyname(2) failed for %s\n", hostname);
+ else {
+ /*
+ * Copy the hostent struct right here, as the static one we got a
+ * pointer to might get removed when we don't want/expect that. Windows
+ * (other platforms?) also doesn't allow passing of the returned data
+ * between threads, which thus the copying here them allows the app to
+ * do.
+ */
+ h = Curl_addrinfo_copy(h);
+ }
+#endif /*HAVE_GETHOSTBYNAME_R */
+ }
+
+ return h;
+}
+
+#endif /* CURLRES_SYNCH */
+
+#endif /* CURLRES_IPV4 */
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