# selftest_mingetty.exp -- exercise mingetty(8) on a real pty.
#
# Driven by tests/88-mingetty.test, in the tagged-value shape 40-tcl.test
# established: one "R<n>-<case> <0|1>" line per assertion, and ALL-MINGETTY-OK
# only when every one of them is 1.
#
# Why expect is needed at all. mingetty is a getty: it opens a terminal BY NAME,
# makes it its controlling terminal (TIOCSCTTY) and refuses to go on unless
# isatty() agrees, so no plain shell pipeline can drive it. The pty expect
# allocates for the spawned process is handed straight back to mingetty as its
# tty argument -- the shell resolves $(tty) on that pty and execs mingetty onto
# it, so the process is already the session leader of the very terminal it is
# asked to open. The console the runner is reporting on is never touched, which
# is the other half of the reason: a getty pointed at the console would seize
# it, and the run would end mid-suite with no output.
#
# --loginprog=/bin/echo stands in for login(1). mingetty's last act is
#   execl(loginprog, loginprog, autologin ? "-f" : "--", name, NULL)
# so echo turns the hand-off itself into the observable: "-f <name>" for an
# automatic login, "-- <name>" for a name typed at the prompt. The real
# /bin/login here is busybox's, which would prompt for a password against a
# shadow file this image has no usable entry in.

set timeout 20
log_user 0

set MG /sbin/mingetty
# Quiet flags shared by every case: no vhangup (case 4 is where that is tested
# on its own), no ESC-c terminal reset, no leading newline, no /etc/issue and no
# hostname -- so each case's output is exactly the one line it asserts on, and
# case 3 is the only one that lets the banner through.
set QUIET "--nohangup --noclear --nonewline --noissue --nohostname"

proc has {hay needle} { expr {[string first $needle $hay] >= 0} }

# drive <opts> <sendline> -- run mingetty on its own pty and return everything
# it wrote there. <sendline> non-empty waits for the login prompt first and
# answers it; the text consumed by that wait is folded back into the result so
# the caller can assert on the prompt too.
proc drive {opts sendline} {
    global MG
    set out ""
    if {[catch {spawn /bin/sh -c "exec $MG $opts \"\$(tty)\""} err]} {
        return "SPAWN-FAILED $err"
    }
    if {$sendline ne ""} {
        expect {
            "login: " { append out $expect_out(buffer); send "$sendline\r" }
            timeout   { }
            eof       { }
        }
    }
    expect {
        -re ".+" { append out $expect_out(buffer); exp_continue }
        timeout  { }
        eof      { }
    }
    catch { wait }
    return $out
}

set fails 0
proc report {name cond} {
    global fails
    set v [expr {$cond ? 1 : 0}]
    if {!$v} { incr fails }
    puts "$name $v"
}

# --- 1. automatic login -------------------------------------------------------
# The whole open_tty() path in one case: chown/chmod the device, open it, take it
# as the controlling terminal, dup2 onto 0/1/2 -- then announce the login and
# exec. Everything after this depends on it, so a zero here explains the rest.
set o1 [drive "$QUIET --autologin bstroot --loginprog=/bin/echo" ""]
report R1-autologin-announce [has $o1 "login: bstroot (automatic login)"]
report R1-autologin-exec     [has $o1 "-f bstroot"]

# --- 2. a name typed at the prompt -------------------------------------------
# get_logname(): tcflush, print "login: ", then read the terminal a byte at a
# time until CR. The "--" argv proves the non-autologin branch of the same execl.
set o2 [drive "$QUIET --loginprog=/bin/echo" "bstuser"]
report R2-prompt [has $o2 "login: "]
report R2-exec   [has $o2 "-- bstuser"]

# --- 3. /etc/issue and its escapes -------------------------------------------
# Dropping --noissue and --nohostname turns do_prompt() into its full form:
# print /etc/issue with backslash escapes expanded, then the hostname. The image
# ships "brintOS (Yocto/wasm32) 0.1 \n \l", so \n (nodename) and \l (this tty)
# are both exercised -- and \l is what proves the expansion ran at all rather
# than the file being copied through verbatim.
set o3 [drive "--nohangup --noclear --nonewline --autologin bstroot --loginprog=/bin/echo" ""]
report R3-issue-text [has $o3 "brintOS"]
report R3-issue-tty  [has $o3 "pts/"]

# --- 4. the DEFAULT path (no --nohangup) --------------------------------------
# Every case above passes --nohangup, so none of them covers the invocation a
# real init actually uses. Left to itself mingetty closes 0/1/2, reopens the
# device as fd 0 and retakes it with TIOCSCTTY -- preceded upstream by a
# vhangup(2) that this port patches out, because on wasm32-hwjs the symbol is
# undefined and wasm-ld's trapping stub kills the process outright rather than
# failing (see the bbappend). This case is what proves the default invocation
# runs at all, so it is deliberately the only one that leaves the flag off.
set o4 [drive "--noclear --nonewline --noissue --nohostname --autologin bstroot --loginprog=/bin/echo" ""]
report R4-default-path-exec [has $o4 "-f bstroot"]

if {$fails == 0} { puts "ALL-MINGETTY-OK" } else { puts "MINGETTY-FAILS $fails" }