Horton

Re: Cleaning up historical portability baggage

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andrew Dunstan <andrew@dunslane.net>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-07-25T14:35:35Z
Lists: pgsql-hackers 
On Sun, Jul 24, 2022 at 12:23 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> After looking through these briefly, I'm pretty concerned about
> whether this won't break our Cygwin build in significant ways.
> For example, lorikeet reports "HAVE_SETSID 1", a condition that
> you want to replace with !WIN32.  The question here is whether
> or not WIN32 is defined in a Cygwin build.  I see some places
> in our code that believe it is not, but others that believe that
> it is --- and the former ones are mostly like
>         #if defined(__CYGWIN__) || defined(WIN32)
> which means they wouldn't actually fail if they are wrong about that.

I spent a large chunk of today figuring out how to build PostgreSQL
under Cygwin/GCC on CI.  My method for answering this question was to
put the following on the end of 192 .c files that contain the pattern
/#if.*WIN32/:

+
+#if defined(WIN32) && defined(__CYGWIN__)
+#pragma message "contradiction"
+#endif

Only one of them printed that message: dirmod.c.  The reason is that
it goes out of its way to include Windows headers:

#if defined(WIN32) || defined(__CYGWIN__)
#ifndef __CYGWIN__
#include <winioctl.h>
#else
#include <windows.h>
#include <w32api/winioctl.h>
#endif
#endif

The chain <windows.h> -> <windef.h> -> <minwindef.h> leads to WIN32 here:

https://github.com/mirror/mingw-w64/blob/master/mingw-w64-headers/include/minwindef.h#L15

I'm left wondering if we should de-confuse matters by ripping out all
the checks and comments that assume that this problem is more
widespread, and then stick a big notice about it in dirmod.c, to
contain this Jekyll/Hide situation safely inside about 8 feet of
concrete.

I'll respond to your other complaints with new patches tomorrow.

Commits

  1. Make sure IOV_MAX is defined.

  2. Doc: Abstract AF_UNIX sockets don't work on Windows.

  3. Clean up inconsistent use of fflush().

  4. Remove configure probe for sockaddr_in6 and require AF_INET6.

  5. Remove configure probes for sockaddr_storage members.

  6. Remove configure probe for netinet/tcp.h.

  7. Fix macro problem with gai_strerror on Windows.

  8. Remove configure probe for net/if.h.

  9. mstcpip.h is not missing on MinGW.

  10. Remove dead ifaddr.c fallback code.

  11. Remove configure probe for gethostbyname_r.

  12. Remove replacement code for getaddrinfo.

  13. Remove configure probe for struct sockaddr_storage.

  14. Remove HAVE_UNIX_SOCKETS.

  15. Remove configurability of PPC spinlock assembly code.

  16. Remove configure probe for shl_load library.

  17. Remove configure probe for sys/select.h.

  18. Remove configure probes for sys/un.h and struct sockaddr_un.

  19. Remove configure probes for sys/ipc.h, sys/sem.h, sys/shm.h.

  20. Remove configure probe for sys/resource.h and refactor.

  21. Remove configure probe for sys/uio.h.

  22. Fix obsolete comments in instr_time.h.

  23. aix: fix misreading of condition in 8f12a4e7add

  24. aix: Remove checks for very old OS versions

  25. windows: Remove HAVE_MINIDUMP_TYPE test

  26. solaris: Remove unnecessary gcc / gnu ld vs sun studio differences

  27. Trust a few system headers to stand on their own

  28. Rely on __func__ being supported

  29. Simplify replacement code for strtof.

  30. Simplify gettimeofday for Windows.

  31. Simplify gettimeofday() fallback logic.

  32. Remove fallbacks for strtoll, strtoull.

  33. Remove configure probe for fdatasync.

  34. Remove configure probe for clock_gettime.

  35. Simplify replacement code for preadv and pwritev.

  36. Remove dead pread and pwrite replacement code.

  37. Remove dead setenv, unsetenv replacement code.

  38. Remove configure probes for poll and poll.h.

  39. Remove configure probe for link.

  40. Remove configure probes for symlink/readlink, and dead code.

  41. Remove configure probe for setsid.

  42. Remove configure probe for shm_open.

  43. Remove configure probe and related tests for getrlimit.

  44. Remove configure probe for dlopen, and refactor.

  45. Remove dead getpwuid_r replacement code.

  46. Remove dead handling for pre-POSIX sigwait().

  47. Remove dead getrusage replacement code.

  48. Cygwin and Mingw floating-point fixes.

  49. Support platforms where strtoll/strtoull are spelled __strtoll/__strtoull.

  50. Arrange to supply declarations for strtoll/strtoull if needed.

  51. Lock down regression testing temporary clusters on Windows.

  52. Secure Unix-domain sockets of "make check" temporary clusters.

  53. Add configure checks for strtoll, strtoull (or strto[u]q). Disable

  54. Portability fix for old SunOS releases: fflush(NULL)