Enable use of sendfile

[exim.git] / src / OS / os.h-Linux

diff --git a/src/OS/os.h-Linux b/src/OS/os.h-Linux
index 5186ec89dde44f645efa85bf55ae03954ed24b8a..3e9303cab8a28a36403b8b0a91c2b8529c87636c 100644 (file)
--- a/src/OS/os.h-Linux
+++ b/src/OS/os.h-Linux
@@ -1,8 +1,8 @@
 /* Exim: OS-specific C header file for Linux */
 
-/* Some weird variants may require invocation with C99 and features.h
-inclusion to build, with the 64-bit arithmetic. Make compiler selection
-their problem, but build anyway. */
+/* Some old systems we've received bug-reports for have a <limits.h> which
+does not pull in <features.h>.  Best to just pull it in now and have done
+with the issue. */
 
 #include <features.h>
 
@@ -18,9 +18,10 @@ their problem, but build anyway. */
 /* When using the DKIM, setting HAVE_LINUX_SENDFILE can increase
 performance on outgoing mail a bit. Note: With older glibc versions
 this setting will conflict with the _FILE_OFFSET_BITS=64 setting
-defined as part of the Linux CFLAGS. */
+defined as part of the Linux CFLAGS.  As of 2017 those are declared
+to be too old to build by default. */
 
-/* #define HAVE_LINUX_SENDFILE */
+#define HAVE_LINUX_SENDFILE
 
 #define F_FREESP     O_TRUNC
 typedef struct flock flock_t;
@@ -44,9 +45,6 @@ storage" as quickly as Exim thinks they are. */
 
 #define NEED_SYNC_DIRECTORY
 
-/* Other OS have "const" in here */
-#define ICONV_ARG2_TYPE char **
-
 #define os_find_running_interfaces os_find_running_interfaces_linux
 
 /* Need a prototype for the Linux-specific function. The structure hasn't
@@ -57,4 +55,26 @@ extern struct ip_address_item *os_find_running_interfaces_linux(void);
 
 #endif /* __linux__ */
 
+/* Some folks running "unusual" setups with very old libc environments have
+found that _GNU_SOURCE=1 before <features.h> is not sufficient to define some
+constants needed for 64-bit arithmetic.  If you encounter build errors based
+on LLONG_MIN being undefined and various other escape hatches have not helped,
+then change the 0 to 1 in the next block. */
+
+#if 0
+# define LLONG_MIN LONG_LONG_MIN
+# define LLONG_MAX LONG_LONG_MAX
+#endif
+
+#if _POSIX_C_SOURCE >= 200809L || _ATFILE_SOUCE
+# define EXIM_HAVE_OPENAT
+#endif
+
+#include <netinet/tcp.h>       /* for TCP_FASTOPEN */
+#include <sys/socket.h>                /* for MSG_FASTOPEN */
+#if defined(TCP_FASTOPEN) && !defined(MSG_FASTOPEN)
+# define MSG_FASTOPEN 0x20000000
+#endif
+
+
 /* End */