Open library file descriptors with O_CLOEXEC
This patch is non-portable, it needs linux 2.6.23 and glibc 2.7
or later, different combinations (old linux, new glibc and vice-versa)
will result in a crash.

To make it portable you have to test O_CLOEXEC support at *runtime*
compile time is not enough.


--- lib/cookie.c.orig
+++ lib/cookie.c
@@ -736,7 +736,7 @@ struct CookieInfo *Curl_cookie_init(stru
     fp = NULL;
   }
   else
-    fp = file?fopen(file, "r"):NULL;
+    fp = file?fopen(file, "re"):NULL;
 
   c->newsession = newsession; /* new session? */
 
@@ -1060,7 +1060,7 @@ static int cookie_output(struct CookieIn
     use_stdout=TRUE;
   }
   else {
-    out = fopen(dumphere, "w");
+    out = fopen(dumphere, "we");
     if(!out)
       return 1; /* failure */
   }
--- lib/file.c.orig
+++ lib/file.c
@@ -249,7 +249,7 @@ static CURLcode file_connect(struct conn
   fd = open_readonly(actual_path, O_RDONLY|O_BINARY);
   file->path = actual_path;
 #else
-  fd = open_readonly(real_path, O_RDONLY);
+  fd = open_readonly(real_path, O_RDONLY|O_CLOEXEC);
   file->path = real_path;
 #endif
   file->freepath = real_path; /* free this when done */
@@ -347,7 +347,7 @@ static CURLcode file_upload(struct conne
   else
     mode = MODE_DEFAULT|O_TRUNC;
 
-  fd = open(file->path, mode, conn->data->set.new_file_perms);
+  fd = open(file->path, mode | O_CLOEXEC, conn->data->set.new_file_perms);
   if(fd < 0) {
     failf(data, "Can't open %s for writing", file->path);
     return CURLE_WRITE_ERROR;
--- lib/formdata.c.orig
+++ lib/formdata.c
@@ -1207,7 +1207,7 @@ CURLcode Curl_getformdata(struct Session
         FILE *fileread;
 
         fileread = strequal("-", file->contents)?
-          stdin:fopen(file->contents, "rb"); /* binary read for win32  */
+          stdin:fopen(file->contents, "rbe"); /* binary read for win32  */
 
         /*
          * VMS: This only allows for stream files on VMS.  Stream files are
@@ -1338,7 +1338,7 @@ static size_t readfromfile(struct Form *
   else {
     if(!form->fp) {
       /* this file hasn't yet been opened */
-      form->fp = fopen(form->data->line, "rb"); /* b is for binary */
+      form->fp = fopen(form->data->line, "rbe"); /* b is for binary */
       if(!form->fp)
         return (size_t)-1; /* failure */
     }
--- lib/hostip6.c.orig
+++ lib/hostip6.c
@@ -45,7 +45,7 @@
 #ifdef HAVE_PROCESS_H
 #include <process.h>
 #endif
-
+#include <fcntl.h>
 #include "urldata.h"
 #include "sendf.h"
 #include "hostip.h"
@@ -113,7 +113,7 @@ bool Curl_ipv6works(void)
   static int ipv6_works = -1;
   if(-1 == ipv6_works) {
     /* probe to see if we have a working IPv6 stack */
-    curl_socket_t s = socket(PF_INET6, SOCK_DGRAM, 0);
+    curl_socket_t s = socket(PF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
     if(s == CURL_SOCKET_BAD)
       /* an ipv6 address was requested but we can't get/use one */
       ipv6_works = 0;
--- lib/if2ip.c.orig
+++ lib/if2ip.c
@@ -153,7 +153,7 @@ char *Curl_if2ip(int af, const char *int
   if(len >= sizeof(req.ifr_name))
     return NULL;
 
-  dummy = socket(AF_INET, SOCK_STREAM, 0);
+  dummy = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
   if(CURL_SOCKET_BAD == dummy)
     return NULL;
 
--- lib/netrc.c.orig
+++ lib/netrc.c
@@ -107,7 +107,7 @@ int Curl_parsenetrc(const char *host,
     netrc_alloc = TRUE;
   }
 
-  file = fopen(netrcfile, "r");
+  file = fopen(netrcfile, "re");
   if(file) {
     char *tok;
     char *tok_buf;
--- lib/ssluse.c.orig
+++ lib/ssluse.c
@@ -437,7 +437,7 @@ int cert_stuff(struct connectdata *conn,
       STACK_OF(X509) *ca = NULL;
       int i;
 
-      f = fopen(cert_file,"rb");
+      f = fopen(cert_file,"rbe");
       if(!f) {
         failf(data, "could not open PKCS12 file '%s'", cert_file);
         return 0;
@@ -2274,7 +2274,7 @@ static CURLcode servercert(struct connec
 
     /* e.g. match issuer name with provided issuer certificate */
     if(data->set.str[STRING_SSL_ISSUERCERT]) {
-      fp=fopen(data->set.str[STRING_SSL_ISSUERCERT],"r");
+      fp=fopen(data->set.str[STRING_SSL_ISSUERCERT],"re");
       if(!fp) {
         if(strict)
           failf(data, "SSL: Unable to open issuer cert (%s)",
--- lib/connect.c.orig
+++ lib/connect.c
@@ -1238,7 +1238,7 @@ CURLcode Curl_socket(struct connectdata
                                     (struct curl_sockaddr *)addr);
   else
     /* opensocket callback not set, so simply create the socket now */
-    *sockfd = socket(addr->family, addr->socktype, addr->protocol);
+    *sockfd = socket(addr->family, addr->socktype | SOCK_CLOEXEC, addr->protocol);
 
   if(*sockfd == CURL_SOCKET_BAD)
     /* no socket, no connection */
--- configure.ac.orig
+++ configure.ac
@@ -180,6 +180,7 @@ AC_CANONICAL_HOST
 dnl Get system canonical name
 AC_DEFINE_UNQUOTED(OS, "${host}", [cpu-machine-OS])
 
+AC_USE_SYSTEM_EXTENSIONS
 dnl Checks for programs.
 CURL_CHECK_PROG_CC
 
@@ -193,6 +194,7 @@ dnl Our configure and build reentrant se
 CURL_CONFIGURE_THREAD_SAFE
 CURL_CONFIGURE_REENTRANT
 
+
 dnl check for how to do large files
 AC_SYS_LARGEFILE
 
--- m4/curl-compilers.m4.orig
+++ m4/curl-compilers.m4
@@ -1272,7 +1272,7 @@ dnl CPPFLAGS from being unexpectedly cha
 AC_DEFUN([CURL_CHECK_PROG_CC], [
   ac_save_CFLAGS="$CFLAGS"
   ac_save_CPPFLAGS="$CPPFLAGS"
-  AC_PROG_CC
+  AC_PROG_CC_STDC
   CFLAGS="$ac_save_CFLAGS"
   CPPFLAGS="$ac_save_CPPFLAGS"
 ])