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authorJohannes Schindelin <johannes.schindelin@gmx.de>2017-06-26 23:15:22 +0200
committerDaniel Stenberg <daniel@haxx.se>2017-07-03 15:45:25 +0200
commitc0cdc68c7eacaa4fda3e2324f8618b6bbe038983 (patch)
treed1b191bc2d7800a89f8be851ced14f76e2b4bb5e /lib
parent3a48a132685ca891ce1b7a10bbcd4b4cd33cee5e (diff)
gtls: fix build when sizeof(long) < sizeof(void *)
- Change gnutls pointer/int macros to pointer/curl_socket_t. Prior to this change they used long type as well. The size of the `long` data type can be shorter than that of pointer types. This is the case most notably on Windows. If C99 were acceptable, we could simply use `intptr_t` here. But we want to retain C89 compatibility. Simply use the trick of performing pointer arithmetic with the NULL pointer: to convert an integer `i` to a pointer, simply take the address of the `i`th element of a hypothetical character array starting at address NULL. To convert back, simply cast the pointer difference. Thanks to Jay Satiro for the initial modification to use curl_socket_t instead of int/long. Closes #1617 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Diffstat (limited to 'lib')
-rw-r--r--lib/vtls/gtls.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/lib/vtls/gtls.c b/lib/vtls/gtls.c
index cbbb61f76..d55f995e8 100644
--- a/lib/vtls/gtls.c
+++ b/lib/vtls/gtls.c
@@ -60,15 +60,13 @@
/* The last #include file should be: */
#include "memdebug.h"
-/*
- Some hackish cast macros based on:
- https://developer.gnome.org/glib/unstable/glib-Type-Conversion-Macros.html
-*/
-#ifndef GNUTLS_POINTER_TO_INT_CAST
-#define GNUTLS_POINTER_TO_INT_CAST(p) ((int) (long) (p))
+#ifndef GNUTLS_POINTER_TO_SOCKET_CAST
+#define GNUTLS_POINTER_TO_SOCKET_CAST(p) \
+ ((curl_socket_t) ((char *)(p) - (char *)NULL))
#endif
-#ifndef GNUTLS_INT_TO_POINTER_CAST
-#define GNUTLS_INT_TO_POINTER_CAST(i) ((void *) (long) (i))
+#ifndef GNUTLS_SOCKET_TO_POINTER_CAST
+#define GNUTLS_SOCKET_TO_POINTER_CAST(s) \
+ ((void *) ((char *)NULL + (s)))
#endif
/* Enable GnuTLS debugging by defining GTLSDEBUG */
@@ -153,7 +151,7 @@ static int gtls_mapped_sockerrno(void)
static ssize_t Curl_gtls_push(void *s, const void *buf, size_t len)
{
- ssize_t ret = swrite(GNUTLS_POINTER_TO_INT_CAST(s), buf, len);
+ ssize_t ret = swrite(GNUTLS_POINTER_TO_SOCKET_CAST(s), buf, len);
#if defined(USE_WINSOCK) && !defined(GNUTLS_MAPS_WINSOCK_ERRORS)
if(ret < 0)
gnutls_transport_set_global_errno(gtls_mapped_sockerrno());
@@ -163,7 +161,7 @@ static ssize_t Curl_gtls_push(void *s, const void *buf, size_t len)
static ssize_t Curl_gtls_pull(void *s, void *buf, size_t len)
{
- ssize_t ret = sread(GNUTLS_POINTER_TO_INT_CAST(s), buf, len);
+ ssize_t ret = sread(GNUTLS_POINTER_TO_SOCKET_CAST(s), buf, len);
#if defined(USE_WINSOCK) && !defined(GNUTLS_MAPS_WINSOCK_ERRORS)
if(ret < 0)
gnutls_transport_set_global_errno(gtls_mapped_sockerrno());
@@ -850,7 +848,7 @@ gtls_connect_step1(struct connectdata *conn,
}
else {
/* file descriptor for the socket */
- transport_ptr = GNUTLS_INT_TO_POINTER_CAST(conn->sock[sockindex]);
+ transport_ptr = GNUTLS_SOCKET_TO_POINTER_CAST(conn->sock[sockindex]);
gnutls_transport_push = Curl_gtls_push;
gnutls_transport_pull = Curl_gtls_pull;
}