plnsub: Make takeoff/landing in mountains consistent
One-way sorties (fly, recon and sweep) reject mountain destinations
with a "Nowhere to land" message. However, planes can land there just
fine when they return to base (bomb, drop, paradrop, missions).
Already inconsistent in BSD Empire 1.1.
Fix the inconsistency by changing pln_where_to_land() to permit only
helicopters to land in mountains, and pln_airbase_ok() to permit only
helicopters and missiles to take off there, i.e. reject fixed-wing
aircraft.
The flying commands now reject fixed-wing planes based in mountains
with an "is in a mountain and can't take off" message.
Commands flying to a mountain now select only helicopters and silently
ignore the rest, exactly like they select only VTOL planes for flying
to a non-airfield. If no planes can be selected, the command fails
with a "No planes could be equipped" message. This is admittedly less
clear than the "Nowhere to land" message we got before.
Missions now ignore fixed-wing planes based in mountains, exactly like
they ignore non-VTOL planes outside airfields. This may make players
wonder why the fixed-wing VTOL planes they transported up that
mountain don't obey missions. Missions are always quiet unless they
execute.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
When bombing land units, the bombers get a chance to spot spies. They
can target one even when it wasn't spotted. This makes no sense.
Screwed up when spy units were added in 4.0.0. Hide them completely.
They can still be killed via collateral damage.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Parameter only_count was introduced so would_abandon() could use
unitsatxy(), but that was a flawed idea, fixed in the previous commit.
No callers passing non-zero remain, so get rid of it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
sct_prewrite() makes an owned sector revert to the deity when there
are no civilians, military or own land units.
would_abandon() tries to predict that, but gets it wrong: it ignores
land units that evade spy detection or are loaded on ships, and it
fails to ignore land units loaded on land units marching out.
Broken in commit 7c1b166, v4.3.33. Fix by counting manually rather
than with unitsatxy().
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
fire: Fix damage and ammunition use of return fire
quiet_bigdef() runs for each attacker. It lets each eligible defender
fire at most once. The first time a defender is eligible, it fires
and is saved in the list of defenders, along with its firing damage.
If it's eligible again for a later attacker, it's found in the list of
defenders, and the damage is reused. The list of defenders searched
with search_flist(). Unfortunately, search_flist() compares only uid,
not type, and therefore can return a previously found defender of
another type.
If there are multiple attackers and multiple defenders with the same
uid, total damage can be off, damage can be spread to attackers out of
range, and defenders may not be charged shells. Abuse is possible,
but complicated to set up, and probably not worth the trouble.
Broken in commit f89edc7, v4.3.12. Fix by comparing the type as well.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
navigate march: Fix abort not to wipe out concurrent updates
When the player aborts the command at the movement prompt, we write
back stale ships or land units, triggering a generation oops. Any
updates made by other threads meanwhile are wiped out, triggering a
seqno mismatch oops.
Broken in commit 24000b4, v4.3.33. Fix by restoring the lost
shp_nav_stay_behind() and lnd_mar_stay_behind() calls.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
march: Fix concurrent updates at sector abandon prompt
When the player declines to abandon a sector, we write back stale land
units, triggering a generation oops. Any updates made by other
threads meanwhile are wiped out, triggering a seqno mismatch oops.
The culprit is lnd_abandon_askyn(): when the player declines, it
returns without calling check_sect_ok(), check_land_ok(). Broken in
commit 7c1b166, v4.3.33. Fix it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
recvclient() calls ef_make_stale() only when it does actual I/O, via
io_output() and io_input(). Missed in commit 2fa5f652, v4.3.24. Call
it directly when it doesn't do actual I/O.
This makes navi-march-test expose a bug in march: when the player
declines to abandon a sector, we write back stale land units,
triggering a generation oops.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
configure: Use -fstack-protector-strong when available
Testing whether the compiler supports it is a bit tricky.
The obvious AX_APPEND_COMPILE_FLAGS([-fstack-protector-strong])
doesn't suffice, since some ports of the GNU toolchain reportedly pass
this test, then fail to link. That's because the compiler accepts the
flag, duly emits references to helper code in libc, but libc doesn't
provide, and linking fails.
Instead, use AX_APPEND_LINK_FLAGS with an input source that makes the
compiler emit the extra stack checking code. This requires the latest
version from the autoconf-archive, so update m4/ax* to commit e3d948b.
Also update m4/my_append_compile_flags.m4 to keep it in sync with
upstream's ax_append_compile_flags.m4.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
configure: Use -fno-strict-aliasing -fno-strict-overflow
Contemporary compilers can squeeze out some extra performance by
assuming the program never executes code that has undefined behavior
according to the C standard. Unfortunately, this can break programs.
Pointing out that these programs are non-conforming is as correct as
it is unhelpful, at least as long as the compiler is unable to
diagnose the non-conformingness.
Since keeping our programs working is a lot more important to us than
running them as fast as possible, forbid some assumptions that are
known to break real-world programs:
* Aliasing: perfectly clean programs don't engage in type-punning, and
perfectly conforming programs do it only in full accordance with the
standard's (subtle!) aliasing rules. Neither kind of perfection is
realistic for us, therefore -fno-strict-aliasing.
* Signed integer overflow: perfectly clean programs won't ever do
signed integer arithmetic that overflows. This is an imperfect
program, therefore -fno-strict-overflow.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
tests: Enable GNU libc memory allocation error checking
MALLOC_CHECK_=3 makes glibc check for memory allocation programming
errors. It's the factory default, but set it anyway just in case
someone disabled it for speed.
Non-zero MALLOC_PERTURB_ makes glibc wipe memory value on allocation
and deallocation. The actual value determines the bit pattern. Set
it to the value of environment variable EMPIRE_CHECK_MALLOC_PERTURB or
else a pseudo-random number, and record it in sandbox/malloc-perturb.
See mallopt(3) for more information.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
When the player aborts the command at the movement prompt, or declines
to abandon a sector, unit_move() returns without freeing the list.
Found with valgrind. Broken in commit 24000b4 and commit 7c1b166,
both v4.3.33.
Free the list on these returns, too.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
navigate march retreat lretreat: Fix read beyond buffer
shp_nav_gauntlet() and lnd_mar_gauntlet() read beyond the list head
when the list is empty. The values read aren't used then. Could
conceivably crash the server anyway, but it's unlikely.
Empty list happens when shp_nav_dir(), lnd_mar_dir() empty the list
and return zero. Broken in commit beedf8d, v4.3.33. Occurs in
navi-march-test (since the last commit) and in retreat-test.
Change shp_nav_dir() and lnd_mar_dir() to return one then. For
additional safety, make shp_nav_gauntlet() and lnd_mar_gauntlet() oops
on empty list and recover safely.
I think I originally found this bug with -fsanitize, but I've since
upgraded, and I can't diagnose it that way anymore.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
bomb drop fly paradrop recon sweep: Fix read before array
The code computing the length of the flight path checks whether the
path ends with 'h'. When getpath() returns an empty path, it accesses
flightpath[-1]. This could set the length to -1 (unlikely), or crash
(even less likely). The former could be abused to gain mobility for
sufficiently inefficient or short-ranged planes. Found with valgrind.
Historically, getpath() could return paths with or without 'h', and
the check was necessary. It returned an empty path only when the
player gave no input, aborting the command. When the player entered
the assembly point's coordinates, it returned "h".
Commit 404a76f7 accidentally changed it to return "" then. Also broke
flying to the assembly point's coordinates. Commit 0f1e14f (v4.3.31)
fixed that part by changing getpath()'s contract: always return paths
without 'h' ("" simply means empty path), and return NULL on invalid
input, including no input.
The flawed check is superfluous since then. Drop it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Provide proper build-time assertions for NSC_SITYPE()
We want to cause a diagnostic when NSC_SITYPE()'s argument isn't
implemented. Commit aa6ad9d's solution is to have the macro expand
into 1/0 then. Works with GCC, but Clang always warns "division by
zero is undefined".
The better, portable way to conditionally break the build is an array
type with a size that's negative when the build should fail, else
positive. Implement that wrapped in a sizeof() to make it an
expression as macro BUILD_ASSERT_ONE(), and use it in NSC_SITYPE().
No more warnings from Clang 3.5.0. GCC still produces its "may be
used uninitialized" false positives.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
subs: Don't squash telegrams together when time goes backwards
We've always squashed them when the time difference is smaller than
TEL_SECONDS, regardless of sign. This involves passing the difference
to abs(), implicitly casting from time_t to int, which triggers a
Clang warning.
I could clean this up to get rid of the warning, but time should never
go backwards, and trying to make things prettier when it does isn't
worthwhile. Simply drop the abs().
While there, drop the function comment. It's been inaccurate since
Empire 3 dropped mail.c, and bogus since commit 17223e8 (v4.3.29)
added tel_cont.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
info: Belatedly update for change of stop prefix to '!'
Commit eb1512d (v4.3.6) added the '=' if stopped before efficiency.
Commit 016249c (v4.3.6) changed it to '!' without updating info ship,
plane, land, nuke.
Reported-by: Harald Katzer Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
... when referring to a function's parameter or a struct/union's
member.
The idea of using FOO comes from the GNU coding standards:
The comment on a function is much clearer if you use the argument
names to speak about the argument values. The variable name
itself should be lower case, but write it in upper case when you
are speaking about the value rather than the variable itself.
Thus, "the inode number NODE_NUM" rather than "an inode".
Upcasing names is problematic for a case-sensitive language like C,
because it can create ambiguity. Moreover, it's too much shouting for
my taste.
GTK-Doc's convention to prefix the identifier with @ makes references
to variables stand out nicely. The rest of the GTK-Doc conventions
make no sense for us, however.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
When AC_PROG_CC detects GCC, Make.mk adds a bunch of flags to CFLAGS.
Works only for flags that any version of gcc in use accepts.
Instead, make configure add the flags that actually work to CFLAGS.
This will let us add flags that work only for some compilers.
The new autoconf macros are from autoconf-archive v2015.02.24.
Unfortunately, AX_APPEND_COMPILE_FLAGS doesn't work reliably for
-Wno-*: gcc complains about unknown -Wno-foo only when other
diagnostics are being produced. Test -Wfoo instead of -Wno-foo, and
rename to MY_APPEND_COMPILE_FLAGS.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Breaks retreat after ship got sunk by bombs or missile.
ship_bomb() and launch_missile() pass .shp_own to retreat_ship().
Wrong after putship(), because putship() resets the owner when the
ship got sunk. retreat_ship() then oopses and fails to retreat the
surviving members of the group.
Other callers save the owner before putting the ship, and pass that.
We could change these two to do the same. But since we're trying to
get a release out, simply revert the broken commit instead.
The __UNCONST() stolen from NetBSD assumes unsigned long can hold a
pointer. Not true with Win64's LLP64 data model. There, we cast the
64 bit pointer to 32 bits and back. Works only because Windows puts
the stack at a very low address, and the casts don't actually change
the pointer.
Dumb it down to a straight cast to void * for safety.
Thanks to Harald Katzer and Ron Koenderink for their help figuring out
the bug's impact.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Redirections and the execute command let the user read and write files
and run programs on the local system.
Restricted mode prevents such access. This is useful when you want to
grant somebody access to just Empire, but not to the host system's
user account that runs the client.
Signed-off-by: Marisa Giancarla <fstltna@me.com> Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
build: Fix inexact calculation of required materials
sector_can_build() computes mat[i] * (effic / 100.0). The division is
inexact. The result gets randomly rounded, so errors are vanishingly
unlikely to screw up material consumption.
However, we require the amount rounded up to be present since commit 1227d2c. Errors *can* screw that up. Fix by avoiding inexact
computation for that part.
We should probably review rounding of inexact values in general.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
tests: Fix for builds outside git-controlled source tree
We run "git ls-files" in the build tree. Doesn't work when the source
directory isn't a git repository, or the build directory is outside
the source directory. Broken in commit 71cb2d8.
Find source files like Make.mk does: if the source tree is a git
repository, use git ls-files, else use sources.mk.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
Deprecated in commit a00f9e2: 'r' with flags, and bad flags after 't'.
Affects flags argument of bmap, sbmap, pbmap, lbmap, nbmap, and
navigate and march sub-command 'B'.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
emp_config() silently truncates WORLD_X to even. Drop that. We could
flag odd WORLD_X as error, but we don't validate the other
configuration values, so why this one? Instead document it needs to
be even. WORLD_Y, too.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
torpedo: Let torpedo hit land only when target is in range
Telling the player his torpedo "slams into land" can give a clue on
the direction to the target. No good when the target is out of range,
because we shouldn't tell the player more than that then.
Screwed up in 4.2.2. Fix by checking range before line of sight.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
info/torpedo: Fix misinformation on submarine identification
Claims the victim of a torpedo attack gets told the attacking ship's
number. This hasn't been the case for submarines since Empire 2.3.
Recent commits again reveal the attacking submarine's number, but only
when it gets hit by return fire. Update info accordingly.
Reported-by: Neeraj Jain <thisisfranz@gmail.com> Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
torpedo fire: Reveal sub hit by return fire or depth charge
This partly reverts a change made in Empire 2.3 to tell a submarine's
opponent only that he's dealing with a "sub" instead of the
submarine's UID and type. Hiding submarines is done by prsub().
Uses:
* Command torpedo: defender depth charges or torpedoes an attacking
submarine
If you can attack a submarine reactively, you should be able to
attack it actively, too. But that requires its UID. Reveal it
again, but keep the type hidden.
* Command fire: defender fires back at a submarine using its deck gun
Submarines need to surface to fire deck guns, so they shouldn't be
treated any different than surface ships. Revert Empire 2.3's
change entirely there, i.e. defender learns type as well as UID.
* Command torpedo: attacking submarine hits its target
Keep the submarine hidden.
* Commands torpedo and fire: attacking ship hits a submarine
The attacker passed the UID as command argument, so it doesn't
matter whether we print it or not. Printing it is simpler to code,
so do that.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
fire: Clean up damage sanity check and printing of range
Repeated for ship, sector and land unit firing. The latter prints
range only when the sanity check succeeds.
Factor out, changing ship and sector to behave like land unit firing.
When the sanity check fails, print "Jammed!" instead of "Klick!",
because "Klick!" suggests no shells. Used to be printed exactly then,
but the condition first became impossible (Chainsaw), then generalized
to "can't fire for whatever reason" (commit 22c6fd8, v4.3.12).
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
The fire command drops depth charges when the target is a submarine in
range and firing ship has the capability. Else, it blindly fires
guns. It used to reject ships that can't use guns, even when they
could use depth charges, but commit 9b0b0dc (v4.3.31) lifted that
restruction. No such ships exist in the stock game.
If the firing ship can't fire guns, shp_fire() returns -1, triggering
an oops. Broken in commit 0757042.
Avoiding dependence of depth charge on gun fire capability is
pleasing, but nevertheless a bad idea without test coverage. Creating
the necessary tests isn't worth it, so put back the traditional
restriction instead.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>