Commit Graph

11 Commits

Author SHA1 Message Date
FRIGN 11e2d472bf Add *fshut() functions to properly flush file streams
This has been a known issue for a long time. Example:

printf "word" > /dev/full

wouldn't report there's not enough space on the device.
This is due to the fact that every libc has internal buffers
for stdout which store fragments of written data until they reach
a certain size or on some callback to flush them all at once to the
kernel.
You can force the libc to flush them with fflush(). In case flushing
fails, you can check the return value of fflush() and report an error.

However, previously, sbase didn't have such checks and without fflush(),
the libc silently flushes the buffers on exit without checking the errors.
No offense, but there's no way for the libc to report errors in the exit-
condition.

GNU coreutils solve this by having onexit-callbacks to handle the flushing
and report issues, but they have obvious deficiencies.
After long discussions on IRC, we came to the conclusion that checking the
return value of every io-function would be a bit too much, and having a
general-purpose fclose-wrapper would be the best way to go.

It turned out that fclose() alone is not enough to detect errors. The right
way to do it is to fflush() + check ferror on the fp and then to a fclose().
This is what fshut does and that's how it's done before each return.
The return value is obviously affected, reporting an error in case a flush
or close failed, but also when reading failed for some reason, the error-
state is caught.

the !!( ... + ...) construction is used to call all functions inside the
brackets and not "terminating" on the first.
We want errors to be reported, but there's no reason to stop flushing buffers
when one other file buffer has issues.
Obviously, functionales come before the flush and ret-logic comes after to
prevent early exits as well without reporting warnings if there are any.

One more advantage of fshut() is that it is even able to report errors
on obscure NFS-setups which the other coreutils are unable to detect,
because they only check the return-value of fflush() and fclose(),
not ferror() as well.
2015-04-05 09:13:56 +01:00
FRIGN 80a394139a Audit hostname(1)
1) Be strict about argc
2) Fix a small error in the manpage
2015-02-28 21:22:55 +01:00
FRIGN 31572c8b0e Clean up #includes 2015-02-14 21:12:23 +01:00
FRIGN eee98ed3a4 Fix coding style
It was about damn time. Consistency is very important in such a
big codebase.
2014-11-13 18:08:43 +00:00
sin e35d9e62a5 Just use HOST_NAME_MAX in hostname(1)
Using sysconf() + malloc() is overkill.
2014-11-13 17:22:02 +00:00
sin 0c5b7b9155 Stop using EXIT_{SUCCESS,FAILURE} 2014-10-02 23:46:59 +01:00
sin 13cbb19adc Fix wrong length for sethostname()
This was messed up in the previous commit.
2014-02-14 15:13:20 +00:00
sin efbce07f94 Use sysconf() instead of HOST_NAME_MAX 2014-02-14 15:03:16 +00:00
sin 3bf464c1d6 Use HOST_NAME_MAX in hostname(1) 2014-02-11 11:01:49 +00:00
sin b5a511dacf Exit with EXIT_SUCCESS/EXIT_FAILURE instead of 0 and 1
Fixed for consistency purposes.
2013-10-07 16:44:22 +01:00
sin 7be94fd3c8 Add hostname(1) 2013-10-05 14:58:55 +01:00