Commit Graph

24 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
Hiltjo Posthuma
398598dbbe paste: fix crash with empty delimiter
reproduce:
	paste -d '' /dev/null
or
	paste -d '\0' /dev/null

show usage() in these cases.
2015-03-30 21:25:23 +02:00
FRIGN
1bc002b44a Audit paste(1)
Well, basically there was not a lot to do, as I already (fortunately)
audited this code a while back.
There were only minor style-changes.
2015-03-17 21:34:38 +01:00
FRIGN
833c2aebb4 Remove mallocarray(...) and use reallocarray(NULL, ...)
After a short correspondence with Otto Moerbeek it turned out
mallocarray() is only in the OpenBSD-Kernel, because the kernel-
malloc doesn't have realloc.
Userspace applications should rather use reallocarray with an
explicit NULL-pointer.

Assuming reallocarray() will become available in c-stdlibs in the
next few years, we nip mallocarray() in the bud to allow an easy
transition to a system-provided version when the day comes.
2015-03-11 10:50:18 +01:00
FRIGN
3c33abc520 Implement mallocarray()
A function used only in the OpenBSD-Kernel as of now, but it surely
provides a helpful interface when you just don't want to make sure
the incoming pointer to erealloc() is really NULL so it behaves
like malloc, making it a bit more safer.

Talking about *allocarray(): It's definitely a major step in code-
hardening. Especially as a system administrator, you should be
able to trust your core tools without having to worry about segfaults
like this, which can easily lead to privilege escalation.

How do the GNU coreutils handle this?
$ strings -n 4611686018427387903
strings: invalid minimum string length -1
$ strings -n 4611686018427387904
strings: invalid minimum string length 0

They silently overflow...

In comparison, sbase:

$ strings -n 4611686018427387903
mallocarray: out of memory
$ strings -n 4611686018427387904
mallocarray: out of memory

The first out of memory is actually a true OOM returned by malloc,
whereas the second one is a detected overflow, which is not marked
in a special way.
Now tell me which diagnostic error-messages are easier to understand.
2015-03-10 22:19:19 +01:00
FRIGN
3b825735d8 Implement reallocarray()
Stateless and I stumbled upon this issue while discussing the
semantics of read, accepting a size_t but only being able to return
ssize_t, effectively lacking the ability to report successful
reads > SSIZE_MAX.
The discussion went along and we came to the topic of input-based
memory allocations. Basically, it was possible for the argument
to a memory-allocation-function to overflow, leading to a segfault
later.
The OpenBSD-guys came up with the ingenious reallocarray-function,
and I implemented it as ereallocarray, which automatically returns
on error.
Read more about it here[0].

A simple testcase is this (courtesy to stateless):
$ sbase-strings -n (2^(32|64) / 4)

This will segfault before this patch and properly return an OOM-
situation afterwards (thanks to the overflow-check in reallocarray).

[0]: http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man3/calloc.3
2015-03-10 21:23:36 +01:00
FRIGN
31572c8b0e Clean up #includes 2015-02-14 21:12:23 +01:00
FRIGN
73577f10a0 Scrap chartorunearr(), introducing utftorunestr()
Interface and function as proposed by cls.

The reasoning behind this function is that cls expressed his
interest to keep memory allocation out of libutf, which is a
very good motive.
This simplifies the function a lot and should also increase the
speed a bit, but the most important factor here is that there's
no malloc anywhere in libutf, making it a lot smaller and more
robust with a smaller attack-surface.

Look at the paste(1) and tr(1) changes for an idiomatic way to
allocate the right amount of space for the Rune-array.
2015-02-11 21:32:09 +01:00
FRIGN
7c578bf5b0 Scrap writerune(), introducing fputrune()
Interface and function as proposed by cls.
Code is also shorter, everything else analogous to fgetrune().
2015-02-11 20:58:00 +01:00
FRIGN
a5ae899a48 Scrap readrune(), introducing fgetrune()
Interface as proposed by cls, but internally rewritten after a few
considerations.
The code is much shorter and to the point, aligning itself with other
standard functions. It should also be much faster, which is not bad.
2015-02-11 20:16:49 +01:00
sin
0779d69df7 paste: No need to make an exception for stdin, just close it at the end 2015-02-10 12:08:06 +00:00
FRIGN
b8b9d983c8 Add unescape() to libutil
formerly known as resolveescapes(), it is of central use to numerous
programs.
This drops a lot of LOC.
2015-01-29 21:52:44 +01:00
FRIGN
cdbc0d5035 Add UTF8-support to paste(1) and refactor parallel()
Hopefully it now is clearer what the heck is going on.
2015-01-29 20:15:50 +01:00
FRIGN
e17b9cdd0a Convert codebase to use emalloc.c utility-functions
This also definitely increases readability and makes OOM-conditions
more consistent.
2014-11-16 10:22:39 +00:00
FRIGN
ec8246bbc6 Un-boolify sbase
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.
2014-11-14 10:54:20 +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
0c5b7b9155 Stop using EXIT_{SUCCESS,FAILURE} 2014-10-02 23:46:59 +01:00
Hiltjo Posthuma
953ebf3573 code style
Signed-off-by: Hiltjo Posthuma <hiltjo@codemadness.org>
2014-06-01 18:02:30 +01:00
Hiltjo Posthuma
f7403ce6c6 style: whitespace fixes
Signed-off-by: Hiltjo Posthuma <hiltjo@codemadness.org>
2014-04-01 16:20:43 +01:00
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
stateless
7216a53a7e Remove unnecessary exit(1) in usage()
Signed-off-by: Christoph Lohmann <20h@r-36.net>
2013-06-19 19:58:19 +02:00
Christoph Lohmann
4d38f60685 Eliminating the getopt disgrace. 2013-06-14 20:20:47 +02:00
Christoph Lohmann
f648c7fa71 Fixing whitespaces. 2013-05-04 07:49:51 +02:00
Lorenzo Cogotti
c451683c3f Added POSIX paste(1) command implementation.
This commit adds a simple implementation of the POSIX
standard paste(1) command, and its man page.
TODO and Makefile have been updated accordingly.

Signed-off-by: Christoph Lohmann <20h@r-36.net>
2013-05-04 07:48:21 +02:00