Exit status of commands

[HaleTom]

I was surprised to see:

% keychain -l
Error connecting to agent: No such file or directory
% echo $?                            
0

Whereas:

% ssh-add -l        
Error connecting to agent: No such file or directory
% echo $?                                                                                          
2

Can keychain return useful exit statuses? (I note there's no EXIT STATUS section in the man page, also)

[manolis-andr]

Problem

keychain always exits with success code 0, even on failure.

Cause

Upon errors, the script calls die() which performs an exit 1, so one would expect to exit with a correct exit code.

However, the problem is that initially the script uses the trap shell builtin to cleanup some lock files when the scripts exits.

keychain/keychain.sh

Lines 1225 to 1235 in 7e37e4b

	# Set up traps
	# Don't use signal names because they don't work on Cygwin.
	if $clearopt; then
	trap '' 2 # disallow ^C until we've had a chance to --clear
	trap 'droplock; exit 1' 1 15 # drop the lock on signal
	trap 'droplock; exit 0' 0 # drop the lock on exit
	else
	# Don't use signal names because they don't work on Cygwin.
	trap 'droplock; exit 1' 1 2 15 # drop the lock on signal
	trap 'droplock; exit 0' 0 # drop the lock on exit
	fi

The trap syntax to run some bash commands upon a signal delivery or on exit is: trap <action> <signal>. To run on shell-exit the <sigspec> should be set to 0 or EXIT. This applies both for dash and bash.

However, the code apart from droplock also issues another exit 0 that masks the previous exit code (see trap 'droplock; exit 0' 0 in the snippet above). So that is why the script always exits with a zero exit code.

Solution

Bourne shell should be able to properly return the previously specified exit code after trap runs the given commands, so to preserve the exit code we should simply remove the exit command from the trap syntax:

- trap 'droplock; exit 0' 0
+ trap 'droplock' 0.

I have sent a patch (#139) but the project does not seem to be actively maintained.

[mrl5]

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