Commit Graph

20 Commits (1d885159f2f7ff68ed75d92af584174a1208ca01)

Author SHA1 Message Date
Evan Gates 123f784ccc printf: handle \0 in %b arguments
The %b case was using fputs after unescape to print the argument, which
meant that it could not handle nul bytes. Instead, store the length
returned from unescape and use fwrite to properly handle them.
2016-12-27 13:25:38 +01:00
pranomostro 229d7cc89a printf: support escaping '%' with '%%'. See printf(1p) EXAMPLES section. 2016-06-27 11:21:47 +01:00
Quentin Rameau 3da450e203 printf: replace strtonum with strtol functions in conversions
Use strtol and strtoul respectively for d, i and o, u, x, X conversions.
This way we can convert other bases than 10, which strtonum doesn't
Also don't exit on conversion error but display a warning, set a return
error code, and continue.
2016-03-01 11:14:42 +00:00
Quentin Rameau 243cdb6669 printf: remove unnecessary string size test 2016-03-01 11:14:42 +00:00
FRIGN d0269af73e Remove debug-code in printf(1) 2015-06-22 20:03:55 +01:00
FRIGN d848bcac4b Fix parameter-usage in printf(1)
1) Don't default to a space for numeric conversions. Instead,
   set flag to 0 and work with it on a case-basis.
   This fixes the wrong output of "printf %d 20" which had a
   space prepended to it (" 20").
2) Add precision for doiuxX, which is zero-padding.
   This fixes the wrong output of "printf %.5d 20" to properly
   print "00020".

Thanks to emg for reporting these!
2015-06-22 20:03:54 +01:00
FRIGN 0b76449414 Add flag support to printf(1)
We skipped flags before, so no real bug, but it's trivial to add
now, so there's no reason not to do it.
2015-04-27 19:33:57 +01:00
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
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-

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
sin ccf0fbcd7b Fix usage for printf(1) 2015-04-03 10:41:38 +01:00
Hiltjo Posthuma c5a51123b1 printf: no need to nul-terminate after strndup 2015-03-27 12:21:13 +01:00
FRIGN 096da1297b Properly handle width and precision in printf(1) 2015-03-26 23:01:26 +01:00
FRIGN c7deb4f2b7 Audit printf(1)
Not a lot to do here, I wrote this less than a month ago. The only
thing I missed was the newline before return.
2015-03-17 21:43:01 +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
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).

2015-03-10 21:23:36 +01:00
FRIGN 5a13865385 Fix \c behaviour
The loop magic broke along the way. Just drop that and write a
proper early exit (= termination).
Now it should work as expected.
2015-02-16 10:31:13 +01:00
sin 92b14e9c77 Use BSD style function definitions 2015-02-15 16:00:32 +00:00
FRIGN dc3a2ffc4a Handle empty format string in printf(1) 2015-02-15 15:20:32 +01:00
FRIGN bafd41e1cf Add printf(1)
This is a particularly interesting program.
I managed to implement everything according to POSIX except how
octal escapes are specified in the standard, which is yet another
format compared to the one demanded for tr(1).
This not only confuses people, it also adds unnecessary cruft
for no real gain.
So in order to be able to use unescape() easily and for consistency,
I used our initial format \o[oo] instead of \0[ooo].

Marked as optional is UTF-8 support for %c in the POSIX specification.
Given how well-developed libutf has become, doing this here was more
or less trivial, putting us yet again ahead of the competition.
2015-02-15 14:46:58 +01:00
sin fe41494ed3 Import printf(1) from OpenBSD 2014-09-28 15:12:15 +01:00