/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2004, Daniel Stenberg, , 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 #include #define _REENTRANT #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__) #include #else #ifdef HAVE_SYS_TYPES_H #include #endif #ifdef HAVE_SYS_SOCKET_H #include #endif #ifdef HAVE_NETINET_IN_H #include #endif #ifdef HAVE_NETDB_H #include #endif #ifdef HAVE_ARPA_INET_H #include #endif #ifdef HAVE_STDLIB_H #include /* required for free() prototypes */ #endif #ifdef HAVE_UNISTD_H #include /* for the close() proto */ #endif #ifdef VMS #include #include #include #endif #endif #ifdef HAVE_SETJMP_H #include #endif #ifdef WIN32 #include #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 #if defined(HAVE_INET_NTOA_R) && !defined(HAVE_INET_NTOA_R_DECL) #include "inet_ntoa_r.h" #endif #include "memory.h" /* The last #include file should be: */ #include "memdebug.h" /*********************************************************************** * 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(in_addr_t 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 */