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dcd6f81025
The function does not return the same value as snprintf() normally does, so readers may be mislead into thinking the code works differently than it actually does. A different function name makes this easier to detect. Reported-by: Tomas Hoger Assisted-by: Daniel Gustafsson Fixes #3296 Closes #3297
309 lines
10 KiB
C
309 lines
10 KiB
C
/***************************************************************************
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* _ _ ____ _
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* Project ___| | | | _ \| |
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* / __| | | | |_) | |
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* | (__| |_| | _ <| |___
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* \___|\___/|_| \_\_____|
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*
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* Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
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*
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* This software is licensed as described in the file COPYING, which
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* you should have received as part of this distribution. The terms
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* are also available at https://curl.haxx.se/docs/copyright.html.
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*
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* You may opt to use, copy, modify, merge, publish, distribute and/or sell
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* copies of the Software, and permit persons to whom the Software is
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* furnished to do so, under the terms of the COPYING file.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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***************************************************************************/
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#include "curl_setup.h"
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/***********************************************************************
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* Only for plain IPv4 builds
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**********************************************************************/
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#ifdef CURLRES_IPV4 /* plain IPv4 code coming up */
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#ifdef HAVE_NETINET_IN_H
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#include <netinet/in.h>
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#endif
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#ifdef HAVE_NETDB_H
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#include <netdb.h>
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#endif
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#ifdef HAVE_ARPA_INET_H
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#include <arpa/inet.h>
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#endif
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#ifdef __VMS
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#include <in.h>
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#include <inet.h>
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#endif
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#ifdef HAVE_PROCESS_H
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#include <process.h>
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#endif
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#include "urldata.h"
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#include "sendf.h"
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#include "hostip.h"
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#include "hash.h"
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#include "share.h"
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#include "strerror.h"
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#include "url.h"
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#include "inet_pton.h"
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/* The last 3 #include files should be in this order */
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#include "curl_printf.h"
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#include "curl_memory.h"
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#include "memdebug.h"
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/*
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* Curl_ipvalid() checks what CURL_IPRESOLVE_* requirements that might've
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* been set and returns TRUE if they are OK.
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*/
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bool Curl_ipvalid(struct connectdata *conn)
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{
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if(conn->ip_version == CURL_IPRESOLVE_V6)
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/* An IPv6 address was requested and we can't get/use one */
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return FALSE;
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return TRUE; /* OK, proceed */
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}
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#ifdef CURLRES_SYNCH
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/*
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* Curl_getaddrinfo() - the IPv4 synchronous version.
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*
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* The original code to this function was from the Dancer source code, written
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* by Bjorn Reese, it has since been patched and modified considerably.
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*
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* gethostbyname_r() is the thread-safe version of the gethostbyname()
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* function. When we build for plain IPv4, we attempt to use this
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* function. There are _three_ different gethostbyname_r() versions, and we
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* detect which one this platform supports in the configure script and set up
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* the HAVE_GETHOSTBYNAME_R_3, HAVE_GETHOSTBYNAME_R_5 or
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* HAVE_GETHOSTBYNAME_R_6 defines accordingly. Note that HAVE_GETADDRBYNAME
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* has the corresponding rules. This is primarily on *nix. Note that some unix
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* flavours have thread-safe versions of the plain gethostbyname() etc.
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*
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*/
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Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
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const char *hostname,
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int port,
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int *waitp)
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{
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Curl_addrinfo *ai = NULL;
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#ifdef CURL_DISABLE_VERBOSE_STRINGS
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(void)conn;
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#endif
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*waitp = 0; /* synchronous response only */
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ai = Curl_ipv4_resolve_r(hostname, port);
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if(!ai)
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infof(conn->data, "Curl_ipv4_resolve_r failed for %s\n", hostname);
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return ai;
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}
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#endif /* CURLRES_SYNCH */
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#endif /* CURLRES_IPV4 */
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#if defined(CURLRES_IPV4) && !defined(CURLRES_ARES)
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/*
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* Curl_ipv4_resolve_r() - ipv4 threadsafe resolver function.
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*
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* This is used for both synchronous and asynchronous resolver builds,
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* implying that only threadsafe code and function calls may be used.
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*
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*/
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Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname,
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int port)
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{
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#if !defined(HAVE_GETADDRINFO_THREADSAFE) && defined(HAVE_GETHOSTBYNAME_R_3)
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int res;
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#endif
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Curl_addrinfo *ai = NULL;
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struct hostent *h = NULL;
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struct in_addr in;
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struct hostent *buf = NULL;
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if(Curl_inet_pton(AF_INET, hostname, &in) > 0)
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/* This is a dotted IP address 123.123.123.123-style */
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return Curl_ip2addr(AF_INET, &in, hostname, port);
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#if defined(HAVE_GETADDRINFO_THREADSAFE)
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else {
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struct addrinfo hints;
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char sbuf[12];
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char *sbufptr = NULL;
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = PF_INET;
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hints.ai_socktype = SOCK_STREAM;
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if(port) {
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msnprintf(sbuf, sizeof(sbuf), "%d", port);
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sbufptr = sbuf;
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}
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(void)Curl_getaddrinfo_ex(hostname, sbufptr, &hints, &ai);
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#elif defined(HAVE_GETHOSTBYNAME_R)
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/*
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* gethostbyname_r() is the preferred resolve function for many platforms.
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* Since there are three different versions of it, the following code is
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* somewhat #ifdef-ridden.
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*/
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else {
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int h_errnop;
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buf = calloc(1, CURL_HOSTENT_SIZE);
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if(!buf)
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return NULL; /* major failure */
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/*
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* The clearing of the buffer is a workaround for a gethostbyname_r bug in
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* qnx nto and it is also _required_ for some of these functions on some
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* platforms.
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*/
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#if defined(HAVE_GETHOSTBYNAME_R_5)
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/* Solaris, IRIX and more */
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h = gethostbyname_r(hostname,
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(struct hostent *)buf,
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(char *)buf + sizeof(struct hostent),
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CURL_HOSTENT_SIZE - sizeof(struct hostent),
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&h_errnop);
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/* If the buffer is too small, it returns NULL and sets errno to
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* ERANGE. The errno is thread safe if this is compiled with
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* -D_REENTRANT as then the 'errno' variable is a macro defined to get
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* used properly for threads.
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*/
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if(h) {
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;
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}
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else
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#elif defined(HAVE_GETHOSTBYNAME_R_6)
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/* Linux */
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(void)gethostbyname_r(hostname,
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(struct hostent *)buf,
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(char *)buf + sizeof(struct hostent),
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CURL_HOSTENT_SIZE - sizeof(struct hostent),
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&h, /* DIFFERENCE */
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&h_errnop);
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/* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a
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* sudden this function returns EAGAIN if the given buffer size is too
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* small. Previous versions are known to return ERANGE for the same
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* problem.
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*
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* This wouldn't be such a big problem if older versions wouldn't
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* sometimes return EAGAIN on a common failure case. Alas, we can't
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* assume that EAGAIN *or* ERANGE means ERANGE for any given version of
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* glibc.
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*
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* For now, we do that and thus we may call the function repeatedly and
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* fail for older glibc versions that return EAGAIN, until we run out of
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* buffer size (step_size grows beyond CURL_HOSTENT_SIZE).
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*
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* If anyone has a better fix, please tell us!
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*
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* -------------------------------------------------------------------
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*
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* On October 23rd 2003, Dan C dug up more details on the mysteries of
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* gethostbyname_r() in glibc:
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*
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* In glibc 2.2.5 the interface is different (this has also been
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* discovered in glibc 2.1.1-6 as shipped by Redhat 6). What I can't
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* explain, is that tests performed on glibc 2.2.4-34 and 2.2.4-32
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* (shipped/upgraded by Redhat 7.2) don't show this behavior!
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*
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* In this "buggy" version, the return code is -1 on error and 'errno'
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* is set to the ERANGE or EAGAIN code. Note that 'errno' is not a
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* thread-safe variable.
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*/
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if(!h) /* failure */
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#elif defined(HAVE_GETHOSTBYNAME_R_3)
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/* AIX, Digital Unix/Tru64, HPUX 10, more? */
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/* For AIX 4.3 or later, we don't use gethostbyname_r() at all, because of
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* the plain fact that it does not return unique full buffers on each
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* call, but instead several of the pointers in the hostent structs will
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* point to the same actual data! This have the unfortunate down-side that
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* our caching system breaks down horribly. Luckily for us though, AIX 4.3
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* and more recent versions have a "completely thread-safe"[*] libc where
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* all the data is stored in thread-specific memory areas making calls to
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* the plain old gethostbyname() work fine even for multi-threaded
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* programs.
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*
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* This AIX 4.3 or later detection is all made in the configure script.
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*
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* Troels Walsted Hansen helped us work this out on March 3rd, 2003.
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*
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* [*] = much later we've found out that it isn't at all "completely
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* thread-safe", but at least the gethostbyname() function is.
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*/
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if(CURL_HOSTENT_SIZE >=
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(sizeof(struct hostent) + sizeof(struct hostent_data))) {
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/* August 22nd, 2000: Albert Chin-A-Young brought an updated version
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* that should work! September 20: Richard Prescott worked on the buffer
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* size dilemma.
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*/
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res = gethostbyname_r(hostname,
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(struct hostent *)buf,
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(struct hostent_data *)((char *)buf +
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sizeof(struct hostent)));
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h_errnop = SOCKERRNO; /* we don't deal with this, but set it anyway */
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}
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else
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res = -1; /* failure, too smallish buffer size */
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if(!res) { /* success */
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h = buf; /* result expected in h */
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/* This is the worst kind of the different gethostbyname_r() interfaces.
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* Since we don't know how big buffer this particular lookup required,
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* we can't realloc down the huge alloc without doing closer analysis of
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* the returned data. Thus, we always use CURL_HOSTENT_SIZE for every
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* name lookup. Fixing this would require an extra malloc() and then
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* calling Curl_addrinfo_copy() that subsequent realloc()s down the new
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* memory area to the actually used amount.
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*/
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}
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else
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#endif /* HAVE_...BYNAME_R_5 || HAVE_...BYNAME_R_6 || HAVE_...BYNAME_R_3 */
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{
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h = NULL; /* set return code to NULL */
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free(buf);
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}
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#else /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */
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/*
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* Here is code for platforms that don't have a thread safe
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* getaddrinfo() nor gethostbyname_r() function or for which
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* gethostbyname() is the preferred one.
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*/
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else {
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h = gethostbyname((void *)hostname);
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#endif /* HAVE_GETADDRINFO_THREADSAFE || HAVE_GETHOSTBYNAME_R */
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}
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if(h) {
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ai = Curl_he2ai(h, port);
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if(buf) /* used a *_r() function */
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free(buf);
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}
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return ai;
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}
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#endif /* defined(CURLRES_IPV4) && !defined(CURLRES_ARES) */
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