Commit Graph

23 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
ac01240800 Small style-fix in cat.c 2015-03-16 10:36:36 +01:00
FRIGN
286df29e7d Make already audited tools argv-centric instead of argc-centric
This has already been suggested by Evan Gates <evan.gates@gmail.com>
and he's totally right about it.
So, what's the problem?
I wrote a testing program asshole.c with

int
main(void)
{
        execl("/path/to/sbase/echo", "echo", "test");
        return 0;
}

and checked the results with glibc and musl. Note that the
sentinel NULL is missing from the end of the argument list.
glibc calculates an argc of 5, musl 4 (instead of 2) and thus
mess up things anyway.
The powerful arg.h also focuses on argv instead of argc as well,
but ignoring argc completely is also the wrong way to go.
Instead, a more idiomatic approach is to check *argv only and
decrement argc on the go.
While at it, I rewrote yes(1) in an argv-centric way as well.

All audited tools have been "fixed" and each following audited
tool will receive the same treatment.
2015-03-02 14:19:26 +01:00
FRIGN
d806f75cb6 Audit cat(1)
1) Fix usage ... spacing
2) use *argv instead of argv[0] in the idiomatic for-loop
3) Stop the naïve usage of "/dev/fd/0" and use plain stdin
   instead (This also makes error-messages more consistent).
4) Add newline before return
5) Remove comma in manpage
2015-03-02 00:39:26 +01:00
FRIGN
31572c8b0e Clean up #includes 2015-02-14 21:12:23 +01:00
Evan Gates
148e6e3b79 read stdin if arg is exactly "-" not just begins with '-' 2014-11-18 21:53:37 +00:00
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
7ffe164106 Modify argv[0] in place 2014-11-13 16:01:22 +00:00
sin
c59894bd5c Implement cat -u and report correct exit condition 2014-11-13 14:56:15 +00:00
sin
0c5b7b9155 Stop using EXIT_{SUCCESS,FAILURE} 2014-10-02 23:46:59 +01:00
sin
5df631ac09 Use /dev/fd/0 as opposed to /dev/stdin 2014-07-04 23:14:26 +01:00
sin
5dc02f757b Add support for '-' to cat
This chunk will need to be librarified at some point.
2014-07-04 16:52:27 +01:00
dwts
b700d5a8ed minor style changes 2014-04-22 13:46:19 +01:00
sin
b8edf3b4ee Add weprintf() and replace fprintf(stderr, ...) calls
There is still some programs left to be updated for this.

Many of these programs would stop on the first file that they
could not open.
2013-11-13 11:41:43 +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
7182076473 Add a usage() function like everywhere else 2013-10-07 16:09:14 +01:00
Christoph Lohmann
f8dc6883a3 Style inquistion for util and some tools. 2013-03-05 21:46:48 +01:00
Connor Lane Smith
171ef71c74 cat: ARGBEGIN 2012-05-31 19:38:18 +01:00
Connor Lane Smith
bf9626d408 add tail 2011-05-26 16:18:42 -01:00
Connor Lane Smith
f458397d5a no, getopt.h is gnu specific 2011-05-24 18:58:36 +01:00
pancake
da547fb294 add missing #include <getopt.h>
do not override CC in config.mk
2011-05-24 14:34:26 +02:00
Connor Lane Smith
4c6c379812 handle -- 2011-05-24 11:05:36 +01:00
Connor Lane Smith
8e26716a5a initial commit 2011-05-23 02:36:34 +01:00