From 9d066935e5e4e0d7477520eeb6fd7b82ce6bebc2 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 3 Oct 2001 21:42:04 +0000
Subject: [PATCH] Keith McGuigan's excellent fix that makes a cloned copy of
 the hostent struct for when gethostbyname() is used so that we have the
 memory of the struct allocated. This turns out to be needed if the curl
 handled is passed between threads on Windows and possibly other operating
 systems where we use that function.

---
 lib/hostip.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/lib/hostip.c b/lib/hostip.c
index 7177554af..4fb25bd47 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -94,6 +94,75 @@ Curl_addrinfo *Curl_getaddrinfo(struct SessionHandle *data,
 }
 #else /* following code is IPv4-only */
 
+/**
+ * Performs a "deep" copy of a hostent into a buffer 
+ * (returns a pointer to the copy).
+ *
+ * Keith McGuigan 
+ * 10/3/2001
+ */
+static struct hostent* pack_hostent(char* buf, struct hostent* orig)
+{
+  char* bufptr;
+  struct hostent* copy;
+
+  int i;
+  char* str;
+  int len;
+
+  bufptr = buf;
+  copy = (struct hostent*)bufptr;
+
+  bufptr += sizeof(struct hostent);
+  copy->h_name = bufptr;
+  len = strlen(orig->h_name) + 1;
+  strncpy(bufptr, orig->h_name, len);
+  bufptr += len;
+
+  copy->h_aliases = (char**)bufptr;
+
+  /* Figure out how many aliases there are */
+  for (i = 0; orig->h_aliases[i] != NULL; ++i);
+
+  /* Reserve room for the array */
+  bufptr += (i + 1) * sizeof(char*);
+
+  i = 0;
+  str = orig->h_aliases[i];
+  while (str != NULL) {
+    len = strlen(str) + 1;
+    strncpy(bufptr, str, len);
+    copy->h_aliases[i] = bufptr;
+    bufptr += len;
+    str = orig->h_aliases[++i];
+  }
+  copy->h_aliases[i] = NULL;
+
+  copy->h_addrtype = orig->h_addrtype;
+  copy->h_length = orig->h_length;
+    
+  copy->h_addr_list = (char**)bufptr;
+
+  /* Figure out how many addresses there are */
+  for (i = 0; orig->h_addr_list[i] != NULL; ++i);
+
+  /* Reserve room for the array */
+  bufptr += (i + 1) * sizeof(char*);
+
+  i = 0;
+  len = orig->h_length;
+  str = orig->h_addr_list[i];
+  while (str != NULL) {
+    memcpy(bufptr, str, len);
+    copy->h_addr_list[i] = bufptr;
+    bufptr += len;
+    str = orig->h_addr_list[++i];
+  }
+  copy->h_addr_list[i] = NULL;
+
+  return copy;
+}
+
 static char *MakeIP(unsigned long num,char *addr, int addr_len)
 {
 #if defined(HAVE_INET_NTOA) || defined(HAVE_INET_NTOA_R)
@@ -217,6 +286,11 @@ Curl_addrinfo *Curl_getaddrinfo(struct SessionHandle *data,
       free(buf);
       *bufp=NULL;
     }
+    else 
+      /* we make a copy of the hostent right now, right here, as the
+         static one we got a pointer to might get removed when we don't
+         want/expect that */
+      h = pack_hostent(buf, h);
 #endif
   }
   return (h);