Currently we request a login shell by passing the -l argument
to the shell. This is either hardcoded, or required to be
specified by the user in the virt-login-shell.conf file.
The standard way for login programs to request a shell run
as a login shell is to modify the argv passed to execve()
so that argv[0] contains the relative shell filename
prefixed with a zero. eg instead of doing
const char **shellargs = ["/bin/bash", "-l", NULL];
execve(shellargs[0], shellargs, env);
We should be doing
const char **shellargs = ["-bash", NULL];
execve("/bin/bash", shellargs, env);
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The virt-login-shell program is supposed to look like a
regular shell to clients. Login services like sshd
expect the shell to accept a '-c cmdstring' argument to
specify a command to launch instead of presenting an
interactive prompt.
We can implement this by simply passing the '-c cmdstring'
data straight through to the real shell we use. This does
not open any security holes, since the command is not run
until we're inside the container namespaces. This allows
scp to work for users with virt-login-shell.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
virt-login-shell was exiting with status 0, regardless of what the
wrapped shell returned. This is unkind to users; we should behave
more like env(1), nice(1), su(1), and other wrapper programs, by
preserving the invoked application's status (which includes the
distinction between death due to signal vs. normal death).
* tools/virt-login-shell.c (main): Pass through child exit status.
* tools/virt-login-shell.pod: Document exit status.
Signed-off-by: Eric Blake <eblake@redhat.com>
Address a number of code, style and docs issues identified
in review of virt-login-shell after it was merged.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Add a virt-login-shell binary that can be set as a user's
shell, such that when they login, it causes them to enter
the LXC container with a name matching their user name.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
