In gnupg/agent/findkey.c we use ftruncate in non-portable way.
IIUC, for portability, es_fflush is required before calling ftruncate.
I encountered an error of gpg-agent (with EFBIG) creating private keys, when a peculiar situation (of using Wine to test gpg-agent.exe on GNU/Linux).
I wonder if Solaris works well.
https://www.man7.org/linux/man-pages/man3/ftruncate.3p.html
https://docs.oracle.com/cd/E19683-01/817-0692/6mgfnkuf8/index.html
| rG GnuPG | |||
| rG9e2307ddf0c2 agent: Flush before calling ftruncate. | |||
| rG99d2931887e5 agent: Flush before calling ftruncate. | |||
iirc, we use ftruncate for ages now. The problem with the name ftruncate is that it looks to similar to the stdio functions. But sure, things should be flushed first.
I created minimized test:
I'm using mingw-w64 10.0.0-2 from Debian testing:
$ i686-w64-mingw32-gcc --version i686-w64-mingw32-gcc (GCC) 10-win32 20210110
With no -D_FILE_OFFSET_BITS=64, it works well (with ftruncate).
Using Wine, it seems that GetDiskFreeSpaceExW fails.
Then, with -D_FILE_OFFSET_BITS=64, it fails, beacuse in this case ftruncate64 in this version of MinGW behaves like POSIX version of ftruncate.
$ i686-w64-mingw32-gcc -D_FILE_OFFSET_BITS=64 -g ftruncate-check.c $ ./a.exe FTELLO: 21 0 FTRUNCATE: 21 27 (-1) ftruncate fail: File too large
Even if it is only a single case (of old version of Wine), I think that it is worth to add es_fflush when writing to file.
I'm going to add it to master.