--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/hostip4.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,308 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2018, 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 https://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 "curl_setup.h"
+
+/***********************************************************************
+ * Only for plain IPv4 builds
+ **********************************************************************/
+#ifdef CURLRES_IPV4 /* plain IPv4 code coming up */
+
+#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 __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"
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+/*
+ * 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[12];
+    char *sbufptr = NULL;
+
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = PF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    if(port) {
+      msnprintf(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) */