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  1. Jul 17, 2017
    • Colin Walters's avatar
      fdio: Add a fchmod wrapper · 547bcea2
      Colin Walters authored
      There are a number of versions of this in ostree at least, might as well wrap
      it.
      547bcea2
    • Colin Walters's avatar
      Remove glnx_stream_fstat() · 8b75c8e3
      Colin Walters authored
      There are only two users of this in ostree, and one of them is
      fairly bogus; we can just use `fstat()`.
      8b75c8e3
    • Colin Walters's avatar
      fdio: Add cleanup+flush API for FILE* · e30a773f
      Colin Walters authored
      Mostly in ostree/rpm-ostree, we work in either raw `int fd`, or
      `G{Input,Output}Stream`.  One exception is the rpm-ostree `/etc/passwd`
      handling, which uses `FILE*` since that's what glibc exposes.
      
      And in general, there are use cases for `FILE*`; the raw `GUnixOutputStream` for
      example isn't buffered, and doing so via e.g. `GBufferedOutputStream` means
      allocating *two* GObjects and even worse going through multiple vfuncs for every
      write.
      
      `FILE*` is used heavily in systemd, and provides buffering. It is a bit cheaper
      than gobjects, but has its own trap; by default every operation locks a mutex.
      For more information on that, see `unlocked_stdio(3)`. However, callers can
      avoid that by using e.g. `fwrite_unlocked`, which I plan to do for most users of
      `FILE*` that aren't writing to one of the standard streams like `stdout` etc.
      e30a773f
  2. Jun 28, 2017
  3. Jun 26, 2017
  4. Jun 14, 2017
    • Colin Walters's avatar
      Add G_IN_SET, patch our internal users via spatch · 9a1b77ef
      Colin Walters authored
      I originally tried to get this into GLib:
      https://bugzilla.gnome.org/show_bug.cgi?id=783751
      
      But that looks like it's going to fail due to MSVC. Let's add it here at least
      so I can start using it tomorrow and not wait for the MSVC team to catch up.
      
      I renamed `glnx-alloca.h` to `glnx-macros.h` as a more natural collective
      home for things from systemd's `macro.h`.
      
      Finally, I used a Coccinelle spatch similar to the one referenced
      in the above BZ to patch our uses.
      9a1b77ef
  5. Jun 13, 2017
  6. May 19, 2017
  7. May 15, 2017
    • Colin Walters's avatar
      fdio: Redo tmpfile API with GLnxTmpfile struct · 9929adcd
      Colin Walters authored
      The core problem with the previous tmpfile code
      is we don't have an autocleanup that calls `unlinkat`
      in the non-`O_TMPFILE` case.  And even if we did, it'd
      be awkward still since the `glnx_link_tmpfile_at()` call
      *consumes* the tmpfile.
      
      Fix this by introducing a struct with a cleanup macro. This simplifies a number
      of the callers in libostree - a notable case is where we had two arrays, one of
      fds, one of paths. It makes other places in libostree a bit more complex, but
      that's because some of the commit code paths want to deal with temporary
      *symlinks* too.
      
      Most callers are better though - in libglnx itself, `glnx_file_copy_at()` now
      correctly unlinks on failure for example.
      9929adcd
  8. Apr 28, 2017
    • Colin Walters's avatar
      fdio: Expose glnx_regfile_copy_bytes(), rewrite: GNU style, POSIX errno · 3a4d0f46
      Colin Walters authored
      NOTE: This changes the error handling API of `glnx_loop_write()` to be
      "old school POSIX" instead of "systemd".
      
      In ostree in a few places we use `g_output_stream_splice()`.  I
      thought this would use `splice()`, but actually it doesn't today.
      
      They also, if a cancellable is provided, end up dropping into `poll()` for every
      read and write. (In addition to copying data to/from userspace).
      
      My opinion on this is - for *local files* that's dumb. In the big picture, you
      really only need cancellation when copying gigabytes. Down the line, we could
      perhaps add a `glnx_copy_bytes_cancellable()` that only did that check e.g.
      every gigabyte of copied data. And when we do that we should use
      `g_cancellable_set_error_if_cancelled()` rather than a `poll()` with the regular
      file FD, since regular files are *always* readable and writable.
      
      For my use case with rpm-ostree though, we don't have gigabyte sized files, and
      seeing all of the `poll()` calls in strace is annoying. So let's have the
      non-cancellable file copying API that's modern and uses both reflink and
      `sendfile()` if available, in that order.
      
      My plan at some point once this is tested more is to migrate this code
      into GLib.
      
      Note that in order to keep our APIs consistent, I switched the systemd-imported
      code to "old school POSIX" error conventions. Otherwise we'd have *3* (POSIX,
      systemd, and GError) and particularly given the first two are easily confused,
      it'd be a recipe for bugs.
      3a4d0f46
  9. Apr 21, 2017
  10. Mar 02, 2017
  11. Oct 25, 2016
    • Colin Walters's avatar
      fdio: Make GLnxFileCopyFlags actually flags · 7d2f577d
      Colin Walters authored
      I wanted to add a new one, and realized it was wrong.  Luckily,
      I think we were safe until now, since the set of bits for `(0, 1, 2)`
      is actually distinct.
      
      Although, hm, callers specifying `GLNX_FILE_COPY_OVERWRITE` may
      have not actually been getting that.
      7d2f577d
  12. Jul 01, 2016
    • Colin Walters's avatar
      fdio: Add open_tmpfile_linkable() and link_tmpfile_at() · 113c770d
      Colin Walters authored
      We had a bug previously where we failed to clean up a temporary file
      in an error path.  This is a classic case where the new `O_TMPFILE`
      API in Linux is nicer.
      
      To implement this, as usual we start with some original bits from
      systemd.  But in this case I ended up having to heavily modify it
      because systemd doesn't support "link into place and overwrite".  They
      don't actually use their tempfile code much at all in fact - as far as
      I can tell, just in the coredump code.
      
      Whereas in many apps, ostree included, a very common use case is
      atomically updating an existing file, which is
      `glnx_file_replace_contents_at()`, including subtleties like doing an
      `fdatasync()` if the file already existed.
      
      Implementing this then is slightly weird since we need to link() the
      file into place, then rename() after.
      
      It's still better though because if we e.g. hit `ENOSPC` halfway
      through, we'll clean up the file automatically.
      
      We still do keep the mode where we error out if the file exists.
      Finally, the ostree core though does have a more unusual case where we
      want to ignore EEXIST (allow concurrent object writers), so add
      support for that now.
      
      Note: One really confusing bug I had here was that `O_TMPFILE` ignores
      the provided mode, and this caused ostree to write refs that weren't
      world readable.
      
      Rework things so we always call `fchmod()`, but as a consequence we're
      no longer honoring umask in the default case.  I doubt anyone will
      care, and if they do we should probably fix ostree to consistently use
      a mode inherited from the repo or something.
      113c770d
  13. May 03, 2016
  14. Jan 11, 2016
    • Colin Walters's avatar
      fdio: Export loop_write · 3c470803
      Colin Walters authored
      I plan to use this in rpm-ostree.  Sad how many times this gets
      reinvented.  Should probably stick a copy in `glib-unix.h` or so.
      3c470803
  15. Apr 09, 2015
  16. Apr 07, 2015
  17. Apr 01, 2015
  18. Mar 05, 2015
    • Colin Walters's avatar
      Add glnx_basename() · 175502e5
      Colin Walters authored
      We have to wrap the glibc version to ensure we get the right version,
      otherwise depending on the variance of includes we may end up crashing
      if we get the POSIX version.
      175502e5
  19. Mar 03, 2015
    • Colin Walters's avatar
      fdio: Add glnx_file_copy_at() · 162d1f6b
      Colin Walters authored
      This will allow deleting some code from OSTree for the config file
      merging.  We're reusing some code from systemd, which a nice modern
      clean codebase, and among other things this gets us BTRFS reflinking
      (if available) again.
      162d1f6b
  20. Feb 20, 2015
    • Colin Walters's avatar
      fdio: New APIs to read/write on fds, fd-relative · 1ebfefa5
      Colin Walters authored
      We don't have this really in GLib, unfortunately.  We do want
      GCancellable, but we also want to operate on raw fds where possible.
      
      The "read a file and validate as UTF-8" is a common use case of mine,
      and this combines that with openat().
      1ebfefa5
  21. Feb 15, 2015
  22. Feb 14, 2015
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