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

/* Exim: OS-specific C header file for Linux */
/* Copyright (c) University of Cambridge 1995 - 2020 */
/* See the file NOTICE for conditions of use and distribution. */


/* 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>
#include <sys/types.h>


#define CRYPT_H
#define GLIBC_IP_OPTIONS
#define HAVE_MMAP
#define HAVE_BSD_GETLOADAVG
#define HAVE_SYS_STATVFS_H
#define NO_IP_VAR_H
#define SIG_IGN_WORKS

/* When using DKIM, setting OS_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.  As of 2017 those are declared
to be too old to build by default. */

#define OS_SENDFILE
extern ssize_t os_sendfile(int, int, off_t *, size_t);

#define F_FREESP     O_TRUNC
typedef struct flock flock_t;

#define os_strsignal strsignal
#define OS_STRSIGNAL

#if defined(__linux__) || defined(__FreeBSD_kernel__) || defined(__NetBSD_kernel__)
# define SIOCGIFCONF_GIVES_ADDR
# define HAVE_SYS_MOUNT_H
#endif

#if defined(__linux__)

/* Some versions of Linux need explicit sync-ing of directories as well as
files. This setting requests that. If the directory is on NFS, it may not
be possible to sync it - in that case, Exim now should ignore the error. But
if you have problems in that area, try undefining this. But be aware that you
may be in a situation where files are not being properly "committed to stable
storage" as quickly as Exim thinks they are. */

#define NEED_SYNC_DIRECTORY

#define os_find_running_interfaces os_find_running_interfaces_linux

/* Need a prototype for the Linux-specific function. The structure hasn't
been defined yet, so we need to pre-declare it. */

struct ip_address_item;
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

/* TCP Fast Open support */

#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
#define EXIM_HAVE_TCPI_UNACKED
#ifndef TCPI_OPT_SYN_DATA
# define TCPI_OPT_SYN_DATA 32
#endif

/* "Abstract" Unix-socket names */
#define EXIM_HAVE_ABSTRACT_UNIX_SOCKETS


/* End */