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Avoid false positive generation oops in navigate and march

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Commit e3cf1e32 (v4.3.27) created make_stale_if_command_arg() to
permit catching more potential yields on input.  Unfortunately, the
implementation of navigate and march sub-commands 'r', 'l' and 's'
breaks it.

do_unit_move() reads units into a unit list at the beginning and at
each stop.  It writes them back when they move or sweep.  If a unit
changed in the file in between, the changes would get wiped out.
Therefore, do_unit_move() must not yield between stops.

do_unit_move() parses sub-commands into player->argp[], then supplies
defaults for missing arguments, so that code using them (radar(),
do_look(), sona(), mine(), landmine()) won't prompt for missing
arguments.  Unclean and brittle.  See also commit 28cc236e and commit
45106ab9.

Unfortunately, make_stale_if_command_arg() doesn't recognize the
difference between these defaulted arguments and parsed arguments, so
it makes objects stale, even though the defaulted arguments can't be
missing.  If a move or sweep follows, it triggers a false positive
generation oops.

To fix, test "points into argument buffer" (only true for parsed
arguments) instead of "is in player->argp[]".  Requires making the
argument buffer accessible: new struct player member argbuf[].  Use it
for parsing commands, in command(), execute(), do_unit_move().  Don't
use it in emp_config(), player_login(), move_ground(), because these
parse something else.
This commit is contained in:
Markus Armbruster 2011-07-03 09:53:39 +02:00
parent 36015e8c0e
commit 3de1e8be28
3 changed files with 9 additions and 23 deletions
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3
src/lib/commands/navi.c
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@ -76,7 +76,6 @@ do_unit_move(struct emp_qelem *ulist, int *together,
int skip = 0;
char buf[1024];
char prompt[128];
char scanspace[1024];
char pathtaken[1024]; /* Doubtful we'll have a path longer than this */
char *pt = pathtaken;
char bmap_flag;
@ -176,7 +175,7 @@ do_unit_move(struct emp_qelem *ulist, int *together,
cp++;
continue;
}
ac = parse(cp, scanspace, player->argp, NULL, NULL, NULL);
ac = parse(cp, player->argbuf, player->argp, NULL, NULL, NULL);
if (ac <= 0) {
player->argp[0] = "";
cp = NULL;