src/OS/os.h-Linux

   1 /* Exim: OS-specific C header file for Linux */
   2 /* Copyright (c) University of Cambridge 1995 - 2018 */
   3 /* See the file NOTICE for conditions of use and distribution. */
   4
   5
   6 /* Some old systems we've received bug-reports for have a <limits.h> which
   7 does not pull in <features.h>.  Best to just pull it in now and have done
   8 with the issue. */
   9
  10 #include <features.h>
  11 #include <sys/types.h>
  12
  13
  14 #define CRYPT_H
  15 #define GLIBC_IP_OPTIONS
  16 #define HAVE_MMAP
  17 #define HAVE_BSD_GETLOADAVG
  18 #define HAVE_SYS_STATVFS_H
  19 #define NO_IP_VAR_H
  20 #define SIG_IGN_WORKS
  21
  22 /* When using DKIM, setting OS_SENDFILE can increase
  23 performance on outgoing mail a bit. Note: With older glibc versions
  24 this setting will conflict with the _FILE_OFFSET_BITS=64 setting
  25 defined as part of the Linux CFLAGS.  As of 2017 those are declared
  26 to be too old to build by default. */
  27
  28 #define OS_SENDFILE
  29 extern ssize_t os_sendfile(int, int, off_t *, size_t);
  30
  31 #define F_FREESP     O_TRUNC
  32 typedef struct flock flock_t;
  33
  34 #define os_strsignal strsignal
  35 #define OS_STRSIGNAL
  36
  37 #if defined(__linux__) || defined(__FreeBSD_kernel__) || defined(__NetBSD_kernel__)
  38 # define SIOCGIFCONF_GIVES_ADDR
  39 # define HAVE_SYS_MOUNT_H
  40 #endif
  41
  42 #if defined(__linux__)
  43
  44 /* Some versions of Linux need explicit sync-ing of directories as well as
  45 files. This setting requests that. If the directory is on NFS, it may not
  46 be possible to sync it - in that case, Exim now should ignore the error. But
  47 if you have problems in that area, try undefining this. But be aware that you
  48 may be in a situation where files are not being properly "committed to stable
  49 storage" as quickly as Exim thinks they are. */
  50
  51 #define NEED_SYNC_DIRECTORY
  52
  53 #define os_find_running_interfaces os_find_running_interfaces_linux
  54
  55 /* Need a prototype for the Linux-specific function. The structure hasn't
  56 been defined yet, so we need to pre-declare it. */
  57
  58 struct ip_address_item;
  59 extern struct ip_address_item *os_find_running_interfaces_linux(void);
  60
  61 #endif /* __linux__ */
  62
  63 /* Some folks running "unusual" setups with very old libc environments have
  64 found that _GNU_SOURCE=1 before <features.h> is not sufficient to define some
  65 constants needed for 64-bit arithmetic.  If you encounter build errors based
  66 on LLONG_MIN being undefined and various other escape hatches have not helped,
  67 then change the 0 to 1 in the next block. */
  68
  69 #if 0
  70 # define LLONG_MIN LONG_LONG_MIN
  71 # define LLONG_MAX LONG_LONG_MAX
  72 #endif
  73
  74 #if _POSIX_C_SOURCE >= 200809L || _ATFILE_SOUCE
  75 # define EXIM_HAVE_OPENAT
  76 #endif
  77
  78 /* TCP Fast Open support */
  79
  80 #include <netinet/tcp.h>        /* for TCP_FASTOPEN */
  81 #include <sys/socket.h>         /* for MSG_FASTOPEN */
  82 #if defined(TCP_FASTOPEN) && !defined(MSG_FASTOPEN)
  83 # define MSG_FASTOPEN 0x20000000
  84 #endif
  85 #define EXIM_HAVE_TCPI_UNACKED
  86 #ifndef TCPI_OPT_SYN_DATA
  87 # define TCPI_OPT_SYN_DATA 32
  88 #endif
  89
  90 /* "Abstract" Unix-socket names */
  91 #define EXIM_HAVE_ABSTRACT_UNIX_SOCKETS
  92
  93
  94 /* End */