Re-implement confirmation support.

* doc/eclat-delete-volume.1: Update.
* doc/eclat-release-address.1: Update.
* doc/eclat.1: Update.
* doc/eclat.conf.5: New section "CONFIRMATION"
* lib/getyn.c (eclat_vgetyn): Negative default stands for no
default at all.
* lib/confirm.c (eclat_confirm_mode): Remove.
(eclat_confirm): Change signature. Act according to the
first argument.
* lib/libeclat.h (eclat_confirm_mode): New enum.
(eclat_confirm): Change signature.
* src/cmdline.opt: Change handling of -Y and -N options.
* src/config.c: New statement "confirm".
* src/cretags.c: Remove call to eclat_confirm.  This is done by
the caller.
* src/delvol.c: Likewise.
* src/reladdr.c: Likewise.
* src/eclat.c (confirm_mode): New variable.
(command) <flags>: New member.
(cmdtab): Mark commands with appropriate flags.
(main): Call eclat_confirm to confirm the command.
* src/eclat.h (confirm_mode): New extern.
(set_command_confirmation): New proto.

* etc/eclat.cfin: Set a reasonably safe confirmation default.

* lib/forlan.c (strtots): Remove unused variable.

1 files changed, 87 insertions, 1 deletions

diff --git a/doc/eclat.conf.5 b/doc/eclat.conf.5
index 2a14e2e..d7599b7 100644
--- a/doc/eclat.conf.5
+++ b/doc/eclat.conf.5
@@ -13,7 +13,7 @@
 .\"
 .\" You should have received a copy of the GNU General Public License
 .\" along with Eclat.  If not, see <http://www.gnu.org/licenses/>.
-.TH ECLAT.CONF 5 "October 16, 2012" "ECLAT" "Eclat User Reference"
+.TH ECLAT.CONF 5 "December 7, 2012" "ECLAT" "Eclat User Reference"
 .SH NAME
 eclat.conf \- configuration file for
 .BR eclat (1).
@@ -533,6 +533,92 @@ expansion.
 .IP \n+[step].
 If the format cannot determined by the above steps, an error is reported
 and the program terminates.
+.SH CONFIRMATION
+Many
+.B eclat
+commands result in modification of your EC2 resources.  Some of them
+are destructive, in the sense that such modifications cannot be undone
+(e.g. deleting of a volume or termination of an instance).  To reduce
+the possibility of careless usage,
+.B eclat
+can be configured to interactively ask for a confirmation when such a
+command is requested.  This is configured by the
+.B confirm
+statement:
+.PP
+.nf
+.in +2
+\fBconfirm\fR \fImode\fR \fBcommand\fR;
+\fBconfirm\fR \fImode\fR (\fBcommand\fR[, \fBcommand\fR...]);
+\fBconfirm\fR \fImode\fR \fIclass\fR;
+.fi
+.PP
+The \fImode\fR argument specifies the requested confirmation mode.
+Its valid values are:
+.TP
+.B tty
+Ask for confirmation if the controlling terminal is a tty, i.e. if
+.B eclat
+is started from the command line.
+.TP
+.B always
+Always ask for confirmation.  If the controlling terminal is not a
+tty, abort the command.
+.TP
+.B positive
+Never ask.  Assume positive confirmation.  This is the default.
+.TP
+.B negative
+Never ask, assuming negative confirmation.
+.PP
+The second argument specifies the commands to which this mode is
+applied.  It can be a single command name or tag, a comma-separated
+list of command names or tags, or a \fBclass\fR of commands.  Valid
+values for \fIclass\fR are:
+.TP
+.B all
+All commands that modify EC2 resources.
+.TP
+.B destructive
+Commands that destructively modify resources.
+.PP
+Consider the following example:
+.PP
+.nf
+.in +2
+confirm tty destructive;
+confirm tty (StopInstance, StartInstance);
+.fi
+.PP
+It instructs
+.B eclat
+to ask for confirmation if one of the destructive commands is
+requested, or if the command is start-instance or stop-instance.
+.PP
+Here is an example of how this modifies the behavior of
+.B release-address
+command:
+.PP
+.nf
+.if +2
+$ \fBeclat release-address 192.168.0.1\fR
+Proceed with release-address [Y/n] _
+.fi
+.PP
+If the response begins with \fBY\fR (case-insensitive), it is taken
+for a positive answer, and the command will be executed.  Otherwise,
+.B eclat
+exits returning code 16 to the shell.
+.PP
+The current confirmation setting can be overridden using the \fB\-Y\fR
+(\fB\-\-yes\fR) or \fB\-N\fR (\fB\-\-no\fR) command line option.  The
+former forces \fBpositive\fN and the latter \fBnegative\fR
+confirmation mode for the requested command, e.g.:
+.PP
+.nf
+.in +2
+$ \fBeclat -Y delete-volume vol-d1234aef\fR
+.fi
 .SH MAPS
 Maps provide a way to translate arbitrary symbolic names to the Amazon
 resource identifiers.  See the section