In response to feedback I received in another thread:
https://lists.gnu.org/r/coreutils/2023-03/msg00002.html
I am prepared to write an updated patch if necessary.
Addressing the following concerns:
- Bash already supports setting argv0
It does and it almost worked. Unfortunately it introduces new variables,
negating the use of env -i. Although I managed to unset the PWD variable,
the SHLVL variable still persists. In the following example, program prints
all arguments and environment variables:
$ env -i bash -c 'exec -a program ./program'
program
PWD=/data/data/com.termux/files/home/dev/coreutils
SHLVL=0
$ env -i bash -c 'unset SHLVL; unset PWD; exec -a program ./program'
program
SHLVL=0
I am not sure if this would be better addressed in bash or env.
Please let me know if I should submit a patch to bash instead.
- Using --title instead of --name
I chose --name in order to be consistent with bash's functionality.
exec [-a name] [command [arguments]]
If -a is supplied, the shell passes name as the zeroth argument
to the executed command.
I am prepared to change the option if necessary.
I also suggest -a and --argv0, the former being consistent with bash.
- NULL argv[0]
I would be glad to add support for this.
I feel like an additional --null-argv0 option is the best implementation.
Given that program arguments can be arbitrary NUL-terminated strings,
if env were to parse a literal "NULL" as a directive to set argv[0] to 0,
it would preclude the user from setting argv[0] to "NULL".
An additional option would explicitly denote the special value.
- zsh supports ARGV0
I did find that possible solution in my searches.
However, it suffers from the same problem as the bash solution:
variables still persist despite env -i, many more than bash,
even after being unset:
$ env -i zsh -c 'unset _ HOME PWD LOGNAME SHLVL OLDPWD; ARGV0=program
./program'
program
SHLVL=0
_=/data/data/com.termux/files/home/dev/coreutils/./program
For these reasons I think this would be a good feature for env.
I apologize for any mistakes, I'm still getting used to using mailing lists.
Thank you for your consideration,
Matheus Moreira
