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: Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-07-23T22:39:27Z
Lists: pgsql-hackers

Attachments

I have committed the first few:

 * "Remove dead getrusage replacement code."
 * "Remove dead handling for pre-POSIX sigwait()."
 * "Remove dead getpwuid_r replacement code."

Here are some more, a couple of which I posted before but I've now
gone a bit further with them in terms of removing configure checks
etc:

 * "Remove dlopen configure probe."
 * "Remove configure probe and extra tests for getrlimit."
 * "Remove configure probe for shm_open."
 * "Remove configure probe for setsid."
 * "Remove configure probes for readlink, and dead code and docs."
 * "Remove configure probe for symlink, and dead code."
 * "Remove configure probe for link."
 * "Remove dead replacement code for clock_gettime()."
 * "Remove configure probes for poll and poll.h."
 * "Remove dead setenv, unsetenv replacement code."
 * "Remove dead pread and pwrite replacement code."
 * "Simplify replacement code for preadv and pwritev."
 * "Remove --disable-thread-safety."

Some of these depend on SUSv2 options (not just "base"), but we
already do that (fsync, ...) and they're all features that are by now
ubiquitous, which means the fallback code is untested and the probes
are pointless.

<archeology-mode>I'd guess the last system we ran on that didn't have
symlinks would have been SVr3-based SCO, HP-UX, DG/UX etc from the
1980s, since they were invented in 4.2BSD in 1983 and adopted by SVr4
in 1988.  The RLIMIT_OFILE stuff seems to be referring to 1BSD or 2BSD
on a PDP, whereas RLIMIT_NOFILE was already used in 4.3BSD in 1986,
which I'd have guessed would be the oldest OS POSTGRES ever actually
ran on, so that must have been cargo culting from something older?</>

The clock_gettime() one only becomes committable once prairiedog's
host switched to NetBSD, so that'll be committed at the same time as
the fdatasync one from a nearby thread.

The setenv/unsetenv one levels up to SUSv3 (= POSIX issue 6, 2001).
That'd be the first time we don't point at SUSv2 (= POSIX issue 5,
199x) to justify a change like this.

I expect there to be further clean-up after the removal of
--disable-thread-safety.

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)