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.
It's not useful when 0 is returned anyway, so be sure that we have a
string with length > 0, this also solves some indexing-gotchas like
"len - 1" and so on.
Also, add checked getline()'s whenever it has been forgotten and
clean up the error-messages.
It actually makes the binaries smaller, the code easier to read
(gems like "val == true", "val == false" are gone) and actually
predictable in the sense of that we actually know what we're
working with (one bitwise operator was quite adventurous and
should now be fixed).
This is also more consistent with the other suckless projects
around which don't use boolean types.
Otherwise, a pattern with a '$' anchor will never match and POSIX says that
"By default, an input line shall be selected if any pattern ... matches any
part of the line excluding the terminating <newline>"
improvements:
- improve statuscode behaviour
- don't exit if a file in a series fails. exit 2 if an error occured
in a file series. don't exit if there is a read error (like: grep
input file is a directory).
- use agetline instead of agets().
with the simple test: time seq 1 100000000 | grep 'a'
its 12 seconds (from 24 seconds) on my machine.
Signed-off-by: Hiltjo Posthuma <hiltjo@codemadness.org>
This reverts commit d9a098ae6bc07188cbaefcd188e5911dec41815d.
Conflicts:
grep.c
Hiltjo Posthuma <hiltjo@codemadness.org> said:
(Re)compiling the regex for each line doesn't make sense (imho) and
slows it down a lot.
A simple test:
time seq 1 100000000 | grep 'a'
sbase grep (before patch):
0m22.21s real 0m0.00s user 0m0.00s system
sbase grep (after patch):
2m16.28s real 0m0.00s user 0m0.00s system
coreutils grep:
0m1.15s real 0m0.00s user 0m0.00s system
So the patch should be reverted I think.
FRIGN
Hiltjo Posthuma
sin
Jakob Kramer
Evan Gates
Michael Forney
dwts
Connor Lane Smith