a bit more with POSIX and the other shells
I considered http://austingroupbugs.net/view.php?id=253 but the use
of bi_errorf() is interesting, especially as it’s often enough a
noreturn function, and funnily enough, 'cd -P /foo' returns 0 while
'chdir -P /foo' fails (so idk where to put -e)…
and switches to the TARGET_OS=Linux
• introduce android as regression test suite category
• add an android specific standard alias
• clean up redundant ‘-o sh’ arg in a few checks
UTF-8 BOM instead (UTFMODE has a separate value now for activated
during BOM skipping)
• parsing a COMSUB now skips UTF-8 BOM, too, but only temporarily
• PIPESTATUS now supported (like bash 2) whose last member
may actually differ from $? since the latter may not be the
result of a pipeline partial command
• add regression tests, documentation, etc.
• in interactive mode, always look up {LC_{ALL,CTYPE},LANG} environment
variables if setlocale/nl_langinfo(CODESET) doesn’t suffice
• add the ability to call any builtin (some don't make sense or wouldn't
work) directly by analysing argv[0]
• for direct builtin calls, the {LC_{ALL,CTYPE},LANG} environment
variables determine utf8-mode, even if MKSH_ASSUME_UTF8 was set
• when called as builtin, echo behaves POSIXish
• add domainname as alias for true on MirBSD only, to be able to link it
• sync mksh Makefiles with Build.sh output
• adjust manpage wrt release plans
• link some things to mksh now that we have callable builtins:
bin/echo bin/kill bin/pwd bin/sleep (exact matches)
bin/test bin/[ (were scripts before)
bin/domainname=usr/bin/true usr/bin/false (move to /bin/ now)
• drop linked utilities and, except for echo and kill, their manpages
• adjust instbin and link a few more there as well
– possible integer overflows in memory allocation, mostly
‣ multiplication: all are checked now
‣ addition: reviewed them, most were “proven” or guessed to be
“almost” impossible to run over (e.g. when we have a string
whose length is taken it is assumed that the length will be
more than only a few bytes below SIZE_MAX, since code and
stack have to fit); some are checked now (e.g. when one of
the summands is an off_t); most of the unchecked ones are
annotated now
⇒ cost (MirBSD/i386 static): +76 .text
⇒ cost (Debian sid/i386): +779 .text -4 .data
– on Linux targets, setuid() setresuid() setresgid() can fail
with EAGAIN; check for that and, if so, warn once and retry
infinitely (other targets to be added later once we know that
they are “insane”)
⇒ cost (Debian sid/i386): +192 .text (includes .rodata)
• setmode.c: Do overflow checking for realloc() too; switch back
from calloc() to a checked malloc() for simplification while there
• define -DIN_MKSH and let setmode.c look a tad nicer while here
│Don't alias 'stop' to 'kill -STOP'
│
│Android has already has a stop command used
│to stop the main runtime and the alias
│interferes with testing tools that expect
│stop to kill the runtime.
│
│Change-Id: I02b7efb9203dc39e97f63eb702a54ff79935b316
Although, this is closer to his first patchset and only takes
care of the alias, not the testsuite (which doesn’t run, at
least not out-of-the-box, nicely anyway) using #ifdef ANDROID.
We certainly want a more flexible testsuite…
and vendor pdksh versions, re-introduce FPOSIX alongside FSH. The semantics
are now:
‣ set -o posix ⇒
• disable brace expansion and FSH when triggered
• use Debian Policy 10.4 compliant non-XSI “echo” builtin
• do not keep file descriptors > 2 to ksh
‣ set -o sh ⇒
• set automatically #ifdef MKSH_BINSHREDUCED
• disable brace expansion and FPOSIX when triggered
• use Debian Policy 10.4 compliant non-XSI “echo” builtin
• do not keep file descriptors > 2 to ksh
• trigger MKSH_MIDNIGHTBSD01ASH_COMPAT mode if compiled in
• make “set -- $(getopt ab:c "$@")” construct work
Note that the set/getopt one used to behave POSIXly only with FSH or
FPOSIX (depending on the mksh version) set and Bourne-ish with it not
set, so this changes default mksh behaviour to POSIX!
• merge the rest of branch tg-wcswidth-behaviour
• enhance test cases for wcswidth-like behaviour
• switch hash table collision resolution algorithm to Python’s as announced
• bump vsn
• use a combination of the one-at-a-time hash and an LCG for handling
the $RANDOM special if !HAVE_ARC4RANDOM instead of rand(3)/srand(3)
and get rid of time(3) usage to reduce import footprint
• raise entropy state (mostly in the !HAVE_ARC4RANDOM case though…)
• simplify handling of the $RANDOM_SPECIAL generally
• tweak hash() to save a temp var for non-optimising compilers
• some int → mksh_ari_t and other type fixes
• general tweaking of code and comments
just a "somewhat more POSIX" but also a "/bin/sh legacy kludge" mode
* consistently capitalise POSIX and SUSv3/SUSv4 (same as AT&T ksh) and
Bourne shell
call it only if $RANDOM is indeed set (although pool extension would be a
possibility we do have arc4random_atexit which does it nicely too)
• avoid calling setspec for int→str conversion just before execve()
to it are now either arc4random or rand/srand, but srand retains the old
state; set +o arc4random is no longer possible, but if it's there we use
arc4random(3), if not, we use rand(3) for $RANDOM reads; optimise special
variable handling too and fix a few consts and other minor things
MKSH_S_EDIT for small (Emacs) editing mode, MKSH_S_FEAT for all the dis-
abled language features), which can be set to 0 despite MKSH_SMALL being
defined to re-enable the Vi command line editing mode (which I wouldn't,
but fits into the general mastermind scheme)
some GNU bash extensions (suggested by cnuke@) and bind macros
* make the random cache more efficient (and the code potentially
smaller, although we have a new implementation of the oaat hash
function, alongside the old one, now) and pushb only if needed
(i.e. state has changed or user has set $RANDOM, but not onfork)
• shell flags are now handled in one single place (sh_flags.h)
• sync comments (between enum and array) and manpage with reality
• FMONITOR is now no longer needed for Hartz IV shells
• we must not set the item pointer to NULL, since subsequent ktscan()
would stop there and not find any later occurrences
possible resolution strategies:
‣ still keep tablep; store a dummy value (either (void *)-1 or, probably
more portable, &ktenter or something like that) as is-free marker
⇒ retains benefit of keeping count of actually used entries
⇒ see below for further discussion
‣ don't keep tablep; revert back to setting entry->flag = 0
⇒ need to ktwalk() or ktsort() for getting number of entries
⇒ most simple code
‣ same but with a twist: make ktscan() set pp to the first one with
!(entry->flag & DEFINED)¹ so that it can subsequently be re-used,
or, more accurate, free’d and the entry pointer re-used
⇒ less chance of texpand()ing when not needed
‣ similar (from kabelaffe@): in ktsearch(), move the one we DID find
to the first unused one
⇒ doesn’t need tablep or something, but has the overall best
memory use
⇒ more complicated ktscan(): needs to check pointer for NULL, for
dummyval, then entry->flag
⇒ makes lookup more expensive
⇒ benefit: self-optimising hash tables
⇒ loss: still need ktwalk() or ktsort()
• when afree()ing in ktremove(), …
① need to take FINUSE into account
• Python-2.5.4/Objects/dictnotes.txt talks about cache lines
‣ linear backward scan is much worse than linear forward scan
(even if we have to calculate the upper C-array bound)
‣ dereferencing the entry pointer in ktscan() is a penalty
• Python-2.5.4/Objects/dictobject.c has a lot of comments and
a rather interesting collision resolution algorithm, which
seems to de-cluster better than linear search at not much
more cost
• clib and libobjfw have unusable (for looking-at-for-ideas)
hash table implementations
this is a no-op change breaking ifdef-out-d code; the most likely
to happen is to switch to the following scheme:
• keep tablep in struct tbl
• use a magic pointer value for ktremove’d entries, deallocate
the struct tbl as soon as possible – if not FINUSE, immediately
inside ktremove()
‣ memory gain, despite needing to have tablep around
• nuke ktdelete, so that all ops go through kt{enter,remove}
‣ gains us accurate fill information
‣ speed gain: ktscan() needs no longer dereference removed entries
‣ memory (ktsort) and speed (ktwalk) gain: removed entries are now
ignored right from the beginning, so tstate->left and the size
of the sorted array are accurate
‣ removed entries no longer can cause texpand() to be invoked
⇒ this does not give us self-optimising tables, but a speed and
memory benefit plus, probably, simplicity of code; we accurately
know how many non-deleted entries are in a keytab so we can cal-
culate if we need to expand, how much space ktsort() is going to
need, and, for when indexed arrays will be converted to use key-
tabs instead of singly linked linear lists, ${#foo[*]} is fast
(although ${!foo[*]}² and ${foo[*]}³ will need some tweaking and
may run a little less quickly)
• shuffle code around, so that things like search/scan and garbage
collection can be re-used
• use Python’s collision resolution algorithm ipv linear search
② the list of keys needs to be sorted, at least for indexed arrays⁴
③ this needs to be sorted by keys, at least for indexed arrays⁴
④ … but this is a nice-to-have for associative arrays⁵ as well
⑤ which we however do not have
it with the array index; var.c says that
│ 1244 /* The table entry is always [0] */
so that we can have a special flag and a union which stores hval for
the table index, the array index otherwise (coïncidentally *hint hint*
they have the same size)
return information needed to do a real ktremove instead of the pseudo
ktdelete operation which merely unsets the DEFINED flag to mark it as
eligible for texpand garbage collection (even worse, !DEFINED entries
are still counted)
tg