grep: fix -A handling in conjunction with -m match limitation

The basic issue here is that grep, when given -m 1, would stop all
line processing once it hit the match count and exit immediately. The
problem with exiting immediately is that -A processing only happens when
subsequent lines are processed and do not match.

The fix here is relatively easy; when bsdgrep matches a line, it resets
the 'tail' of the matching context to the value supplied to -A and
dumps anything that's been queued up for -B. After the current line has
been printed and tail is reset, we check our mcount and do what's
needed. Therefore, at the time that we decide we're doing nothing, we
know that 'tail' of the context is correct and we can simply continue
on if there's still more to pick up.

With this change, we still bail out immediately if there's been no -A
flag. If -A was supplied, we signal that we should continue on. However,
subsequent lines will not even bothere to try and process the line. We
have reached the match count, so even if the next line would match then
we must process it if it hadn't. Thus, the loop in procfile() can
short-circuit and just process the line as a non-match until
procmatches() indicates that it's safe to stop.

A test has been added to reflect both that we should be picking up the
next line and that the next line should be considered a non-match even
if it should have been.

PR: 253350
MFC-after: 3 days

grep: fix null pattern and empty pattern file behavior

The null pattern semantics were terrible because I tried to match gnugrep,
but I got it wrong. Let's unwind that:

- The null pattern should match every line if neither -w nor -x.
- The null pattern should match empty lines if -x.
- The null pattern should not match any lines if -w.

The first two will stop processing (shortcut) even if additional patterns
are specified. In any other case, we will continue processing other
patterns. If no other patterns are specified beside a null pattern, then
we match if neither -w nor -x or set and do not match if either of those
are specified.

The justification for -w is that it should match on a whole word, but the
null pattern deos not have a whole word to match on.

Empty pattern files should never match anything, and more importantly, -v
should cause everything to be written.

PR: 253209
MFC-after: 4 days

zgrep: fix exit status with multiple files

zgrep should exit with success when given multiple files and the
pattern is found in at least one file. Prior to this change,
it would exit with success only if the pattern was found in _every_ file.

Reviewed by: dab ngie
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D26616

Fix some regressions with the zgrep(1) wrapper.

- Handle whitespace with long flags that take arguments:

echo 'foo bar' > test
zgrep --regexp='foo bar' test

- Do not hang reading from stdin with patterns in a file:

echo foobar > test
echo foo > pattern
zgrep -f pattern test
zgrep --file=pattern test

- Handle any flags after -e:

echo foobar > test
zgrep -e foo --ignore-case < test

These two are still outstanding problems:

- Does not handle flags that take an argument if there is no
whitespace:

zgrep -enfs /etc/rpc

- When more than one -e pattern used matching should occur for all
patterns (similar to multiple patterns supplied with -f file).
Instead only the last pattern is used for matching:

zgrep -e rex -e nfs /etc/rpc

(This problem is masked in the unpatched version by the "any
flags after -e" problem.)

Add tests for the above problems.

Update the mange and add references to gzip(1) and zstd(1) and also
document the remaining known problems.

PR: 247126
Approved by: markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D25613

bsdgrep(1): various fixes of empty pattern/exit code/-c behavior

When an empty pattern is encountered in the pattern list, I had previously
broken bsdgrep to count that as a "match all" and ignore any other patterns
in the list. This commit rectifies that mistake, among others:

- The -v flag semantics were not quite right; lines matched should have been
counted differently based on whether the -v flag was set or not. procline
now definitively returns whether it's matched or not, and interpreting
that result has been kicked up a level.
- Empty patterns with the -x flag was broken similarly to empty patterns
with the -w flag. The former is a whole-line match and should be more
strict, only matching blank lines. No -x and no -w will will match the
empty string at the beginning of each line.
- The exit code with -L was broken, w.r.t. modern grep. Modern grap will
exit(0) if any file that didn't match was output, so our interpretation
was simply backwards. The new interpretation makes sense to me.

Tests updated and added to try and catch some of this.

This misbehavior was found by autoconf while fixing ports found in PR 229925
expecting either a more sane or a more GNU-like sed.

MFC after: 1 week

netbsd-tests: bsdgrep(1): Add a test for -m, too

netbsd-tests: grep(1): Add test for -c flag

Someone might be inclined to accidentally break this. someone might have
written said test because they broke it locally.

Remove t_grep:mmap_eof_not_eol test

The test was marked as an expected failure in r320414 after r319971's import
of a newer jemalloc removed an essential feature (opt.redzone) for
reproducing the behavior it was testing. Since then, no way has been found
or demonstrated to reliably test the behavior, so remove the test.

PR: 220309

bsdgrep: add some additional tests for fgrep

Previously added tests only check that fgrep is somewhat sane and works. Add
some more tests that check that the implementation is basically functional
and not producing incorrect results with various flags.

Reviewed by: cem, emaste, ngie
Approved by: emaste (mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D12056

bsdgrep(1): Don't exit before processing every file

Given an empty pattern (i.e. grep "" A B), bsdgrep(1) would previously exit()
with the appropriate exit code upon encountering an empty file. Likely intended
as an optimization, but this behavior is technically incorrect since an empty
pattern should match every line.

PR: 220924
Reviewed by: emaste, cem (earlier version), ngie
Approved by: emaste (mentor)
Differential Revision: https://reviews.freebsd.org/D11698

Expect :mmap_eof_not_eol to fail

It relies on a jemalloc feature (opt.redzone) no longer available after
r319971.

MFC with: r318908, r319971
PR: 220309

bsdgrep: add --mmap tests

Basic sanity tests as well as coverage for the bug fixed in r318565.

Submitted by: Kyle Evans <kevans91@ksu.edu>
Reviewed by: bapt, ngie
Differential Revision: https://reviews.freebsd.org/D10827

bsdgrep: Correct per-line line metadata printing

Metadata printing with -b, -H, or -n flags suffered from a few flaws:

1) -b/offset printing was broken when used in conjunction with -o

2) With -o, bsdgrep did not print metadata for every match/line, just
the first match of a line

3) There were no tests for this

Address these issues by outputting this data per-match if the -o flag is
specified, and prior to outputting any matches if -o but not --color,
since --color alone will not generate a new line of output for every
iteration over the matches.

To correct -b output, fudge the line offset as we're printing matches.

While here, make sure we're using grep_printline in -A context. Context
printing should *never* look at the parsing context, just the line.

The tests included do not pass with gnugrep in base due to it exhibiting
similar quirky behavior that bsdgrep previously exhibited.

Submitted by: Kyle Evans <kevans91@ksu.edu>
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D10580

bsdgrep: emit more than MAX_LINE_MATCHES per line

We should not set an arbitrary cap on the number of matches on a line,
and in any case MAX_LINE_MATCHES of 32 is much too low. Instead, if we
match more than MAX_LINE_MATCHES, keep processing and matching from the
last match until all are found.

For the regression test, we produce 4096 matches (larger than we expect
we'll ever set MAX_LINE_MATCHES) and make sure we actually get 4096
lines of output with the -o flag.

We'll also make sure that every distinct line is getting its own line
number to detect line metadata not being printed as appropriate along
the way.

PR: 218811
Submitted by: Kyle Evans <kevans91@ksu.edu>
Reported by: jbeich
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D10577

bsdgrep: add more tests for different binary flags

The existing 'binary' test in netbsd-tests/ does a basic check of the
default treatment for binary behavior, but not much more than that.
Given some opportunity for breakage recently that did not trigger any
failures, add some tests to cover the three different binary file
behaviors (a, -I, -U) and their --binary-files= equivalent values.

Submitted by: Kyle Evans <kevans91@ksu.edu>
Reviewed by: cem, ngie
Differential Revision: https://reviews.freebsd.org/D10620

bsdgrep: don't allow negative -A / -B / -C

Previously, when given a negative -A/-B/-C argument bsdgrep would
overflow the respective context flag(s) and exhibited surprising
behavior.

Fix this by removing unsignedness of Aflag/Bflag and erroring out if
we're given a value < 0. Also adjust the type used to track 'tail'
context in procfile() so that it accurately reflects the Aflag value
rather than overflowing and losing trailing context.

This also fixes an inconsistency previously existing between -n and
-C "n" behavior. They are now both limited to LLONG_MAX, to be
consistent.

Add some test cases to make sure grep errors out properly for both
negative context values as well as non-numeric context values rather
than giving bogus matches.

Submitted by: Kyle Evans <kevans91@ksu.edu>
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D10675

Remove expected failure that no longer fails with gnu grep in base

Reported by: Jenkins
Submitted by: Kyle Evans <kevans91@ksu.edu>
Sponsored by: Dell EMC Isilon

bsdgrep: don't ouptut matches with -c, -l, -L

Refactoring done in r317703 broke -c, -l, and -L flags implying
suppression of match printing. Fortunately this is just a matter of not
doing any printing of the resulting matches and context printing was not
broken in this refactoring.

Add some regression tests since this area may still see further
refactoring, include different context flags as well even though they
were not broken in this case.

PR: 219077
Submitted by: Kyle kevans91@ksu.edu
Reported by: markj
Reviewed by: cem, ngie
Differential Revision: https://reviews.freebsd.org/D10607

bsdgrep: fix -w flag matching with an empty pattern

-w flag matching with an empty pattern was generally 'broken', allowing
matches to occur on any line whether or not it actually matches -w
criteria.

This fix required a good amount of refactoring to address. procline()
is altered to *only* process the line and return whether it was a match
or not, necessary to be able to short-circuit the whole function in case
of this matchall flag. -m flag handling is moved out as well because it
suffers from the same fate as context handling if we bypass any actual
pattern matching.

The matching context (matches, mostly) didn't previously exist outside
of procline(), so we go ahead and create context object for file
processing bits to pass around. grep_printline() was created due to
this, for the scenarios where the matches don't actually matter and we
just want to print a line or two, a la flushing the context queue and
no -o or --color specified.

Damage from this broken behavior would have been mitigated by the fact
that it is unlikely users would invoke grep -w with an empty pattern.

This was identified while checking PR 105221 for problems it this may
cause in BSD grep, but PR 105221 is *not* a report of this behavior.

Submitted by: Kyle Evans <kevans91 at ksu.edu>
Differential Revision: https://reviews.freebsd.org/D10433

bsdgrep: revise test case which will soon become a failure

Work in progress (D10315) is going to make egrep_empty_invalid an
actually invalid regex, to be consistent with the equivalent BRE "{"
behavior, when using regex(3).

Any non-0 exit value is acceptable, depending on how the installed grep
interprets the expression. GNU grep interprets it as non-matching, and
in the future BSD grep will interpret it is an error.

Submitted by: Kyle Evans <kevans91 at ksu.edu>
Reviewed by: cem, ngie
Differential Revision: https://reviews.freebsd.org/D10572`

bsdgrep: fix -w -v matching improperly with certain patterns

-w and -v flag matching was mostly functional but had some minor
problems:

1. -w flag processing only allowed one iteration through pattern
matching on a line. This was problematic if one pattern could match
more than once, or if there were multiple patterns and the earliest/
longest match was not the most ideal, and

2. Previous work "fixed" things to not further process a line if the
first iteration through patterns produced no matches. This is clearly
wrong if we're dealing with the more restrictive -w matching.

#2 breakage could have also occurred before recent broad rewrites, but
it would be more arbitrary based on input patterns as to whether or not
it actually affected things.

Fix both of these by forcing a retry of the patterns after advancing
just past the start of the first match if we're doing more restrictive
-w matching and we didn't get any hits to start with. Also move -v flag
processing outside of the loop so that we have a greater change to match
in the more restrictive cases. This wasn't strictly wrong, but it could
be a little more error prone.

While here, introduce some regressions tests for this behavior and fix
some excessive wrapping nearby that hindered readability. GNU grep
passes these new tests.

PR: 218467, 218811
Submitted by: Kyle Evans <kevans91 at ksu.edu>
Reviewed by: cem, ngie
Differential Revision: https://reviews.freebsd.org/D10329

Add more sanity tests for grep, egrep, and fgrep

The test suite currently lacks basic sanity checks to ensure that egrep,
fgrep, and grep are actually matching the right expression types, i.e. passing
the right flags to regcomp(3). Amend the test suite to make sure that not only
are the individual versions doing the right thing, but also that we don't have some
kind of frankenregex situation happening where egrep is accepting a BRE or
grep an ERE.

I've chosen to not expand the 'basic' test but to add the 'grep_sanity' checks
to their own test case since this is testing for more than just 'grep matches things',
but actual expression types.

Differential Revision: D10444
Reviewed by: emaste, ngie
Submitted by: Kyle Evans <kevans91@ksu.edu>
Tested with: bsdgrep, gnu grep (base, ports)
Sponsored by: Dell EMC Isilon

Remove the expected failures for :context and :context2 with bsdgrep(1)

They're no longer needed after recent fixes made to bsdgrep(1).

Submitted by: Kyle Evans <kevans91@ksu.edu> (via a previous diff in D10433)
Sponsored by: Dell EMC Isilon

bsdgrep: fix zero-length matches without the -o flag

r316477 broke zero-length matches when not using the -o flag, by
skipping over them entirely.

Add a regression test so that it doesn't break again in the future.

Submitted by: Kyle Evans <kevans91 at ksu.edu>
Reviewed by: cem emaste ngie
Differential Revision: https://reviews.freebsd.org/D10333

Fix expectations for testcases per bsdgrep vs gnu grep from base/ports

The following failures occur with various versions of grep:

BSD grep:
- :context
- :context2

GNU grep (base):
- :color
- :oflag_zerolen

GNU grep (ports):
- :recurse_symlink

Tested with: bsdgrep (^/head@r316542), gnu grep (base/2.5.1), gnu grep (ports/2.27)
Reported by: Jenkins (bsdgrep failures)
Sponsored by: Dell EMC Isilon

bsdgrep: create additional tests for coverage on recent fixes

Create additional tests to cover regressions that were discovered by
PRs linked to reviews D10098, D10102, and D10104.

It is worth noting that neither bsdgrep(1) nor gnugrep(1) in the base
system currently pass all of these tests, and gnugrep(1) not quite being
up to snuff was also noted in at least one of the PRs.

PR: 175314 202022 195763 180990 197555 197531 181263 209116
Submitted by: Kyle Evans <kevans91@ksu.edu>
Reviewed by: cem, ngie, emaste
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D10112

Fix grep_test:recurse with ZFS and TMPFS tmpdirs

contrib/netbsd-tests/usr.bin/grep/t_grep.sh
Fix grep_test:recurse when /tmp is either zfs or tmpfs. The test was
relying on an implicit ordering of directory recursion which happens
to be true when using UFS. grep's specification requires no such
ordering. The solution is to ignore the order of grep's results.

Reviewed by: ngie
MFC after: 32 days
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D4925

Use stable output to a test file instead of depending on the OS name being
grep'able in /bin/sh

This fixes the situation where the OS has been rebranded to something other
than `FreeBSD`

MFC after: 1 week
Obtained from: Isilon OneFS (^/onefs/head@r511419)
Reviewed by: cem, Daniel O'Connor <darius@dons.net.au>
Sponsored by: EMC / Isilon Storage Division