# BST-TIMEOUT: 300
. "$BST_LIB"
require iotop iotop/present

# iotop 1.26 -- Tomas-M/iotop, the C rewrite of the per-process I/O monitor
# (meta-oe recipes-extended, installed as /usr/sbin/iotop). 85-htop covers the
# frame-drawing shape and 85-atop the parseable-record shape; this file drives
# the ONE surface iotop has that needs no terminal, `-b` batch mode, which is
# also the pass criterion this port was opened against.
#
# THE SUITE SPLITS IN TWO AND THE SPLIT IS THE POINT. Everything above the
# "SAMPLING" banner is green and stays green: it is the argument handling that
# exits inside parse_args() -- main.c calls parse_args() BEFORE system_checks()
# (main.c:4-6), and -v/-h exit from inside it (main.c:251-259), so those cases
# never reach the kernel facility the rest of the program is built on.
# Everything below the banner is RED on this image, for a platform reason iotop
# cannot defend against, and is written to assert what a WORKING platform
# produces so the cases flip green by themselves when the kernel gains the
# option (the 85-atop / 85-nmon / 99-sharutils convention).
#
# WHY EVERY SAMPLE IS RED: this kernel is built without CONFIG_TASKSTATS, and
# with it without CONFIG_TASK_XACCT/CONFIG_TASK_IO_ACCOUNTING, which is what
# creates /proc/<pid>/io. arch/wasm32/configs/wasm32_defconfig says so in its
# own words -- `# CONFIG_TASKSTATS is not set`, in a block whose stated reason
# is "genetlink consumer -- nothing reads it yet". iotop IS that reader: it
# takes per-task I/O over a NETLINK_GENERIC taskstats socket
# (xxxid_info.c:97-115), and there is no /proc-only mode to fall back to.
#
# THE REFUSAL IS FAST AND CLEAN, SO NO IOTOP INVOCATION NEEDS BOUNDING.
# system_checks() (checks.c) stats /proc/self/io first and returns 1 when it is
# absent, so iotop exits 1 with its own diagnostic BEFORE it opens a netlink
# socket and before it walks /proc at all. That matters here twice over: it is
# a deterministic message rather than a hang, and it means this suite never
# reaches the whole-/proc walk that hangs procps' top and vmstat on this arm
# (brintos/linux#9). No case below wraps iotop in `arun` or a background
# subshell -- unlike 85-atop, whose every sampling case had to be rationed.
#
# WHAT DOES NEED BOUNDING IS THE WRITER, and the marker at the top of this file
# is there for it alone. The last case backgrounds a `dd` so that iotop has
# something to see; writes on this guest are slow and `kill` does not deliver
# here (brintos/linux#21), so an oversized writer is unreapable and eats the
# runner's bound. It is sized and reaped accordingly -- see that case. The
# 300 s marker is headroom for it against the runner's 60 s default, not a
# claim that iotop is slow.
#
# THE ORDER IS DELIBERATE: the CLI cases come FIRST so they are emitted even if
# a later case runs long, the same reason 85-htop puts its CLI surface ahead of
# its frames.

# icheck <id> <want-rc> <needle> <cmd...> : ok iff <cmd> exits <want-rc> AND
# says <needle>. check_out cannot express this -- it requires rc 0 as well as
# the needle -- and iotop's refusals are all non-zero statuses carrying the
# message that explains them, so asserting the two separately would leave the
# message unchecked or the status unasserted. Same helper shape as 85-atop's
# rcout and 85-htop's hrcout.
icheck() {
  _id=$1; _want=$2; _needle=$3; shift 3
  _o=$("$@" </dev/null 2>&1); _r=$?
  case "$_o" in *"$_needle"*) _h=1 ;; *) _h=0 ;; esac
  if [ "$_r" -eq "$_want" ] && [ "$_h" -eq 1 ]; then bst_ok "$_id"
  elif bst_execfail "$_o"; then bst_unrun "$_id" "$_o"
  else bst_notok "$_id" "rc=$_r want=$_want needle:'$_needle' got:'$(_bst_1line "$_o")'"; fi
}

# ---- packaging --------------------------------------------------------------
# iotop's Makefile installs to $(PREFIX)/sbin, not bindir. Asserting where it
# resolves catches a packaging change that leaves it off the PATH the runner
# actually has (same case as 63-tunctl.test).
check_eq iotop/resolves-to-sbin "/usr/sbin/iotop" "$(command -v iotop)"

# ---- the CLI surface: no netlink, no /proc ---------------------------------
# -v prints argv[0] and VERSION together (main.c:252), so the needle pins the
# built version rather than merely "something answered".
icheck iotop/version   0 "iotop 1.26" iotop --version
icheck iotop/help-rc   0 "Usage:"     iotop --help
# The two options this suite's red half drives, asserted out of the help text so
# a build that dropped batch mode is caught here rather than below.
icheck iotop/help-batch 0 "-b, --batch"    iotop --help
icheck iotop/help-iter  0 "--iter=NUM"     iotop --help
# The only non-zero status iotop has that is not the requirements refusal.
icheck iotop/bad-option 1 "unrecognized option" iotop --nosuchopt

# ---- SAMPLING: red on this image, brintos/linux#72 -------------------------
# Each case asserts what a working platform produces. The detail carries iotop's
# own diagnostic, which names the three kernel options by name -- so a reader
# of a red run needs nothing but the result line to see what is missing.

# The platform fact itself, asserted directly rather than only through iotop, so
# a run says whether the KERNEL changed independently of whether iotop did.
# system_checks() reads exactly this file (checks.c: stat("/proc/self/io")).
if [ -r /proc/self/io ]; then bst_ok iotop/kernel-io-accounting
else bst_notok iotop/kernel-io-accounting "brintos/linux#72: /proc/self/io absent -- this kernel is built without CONFIG_TASKSTATS, so CONFIG_TASK_XACCT/CONFIG_TASK_IO_ACCOUNTING cannot be set either"; fi

# idiag <output> : name WHICH failure this is, for a red case's detail. iotop's
# requirements refusal names the three kernel options itself, so a red carrying
# that text is the known gap; anything else is a NEW failure and says so rather
# than being filed under the same issue by a detail string that assumed it.
# This is what a green "the refusal text is still what we expect" case would
# have bought -- without a case that has to go red the day the kernel is fixed.
idiag() {
  case "$1" in
    *"I/O accounting support (CONFIG_TASKSTATS, CONFIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING)"*)
        printf 'brintos/linux#72: iotop refused on the known kernel gap' ;;
    *)  printf 'UNEXPECTED -- not the brintos/linux#72 requirements refusal' ;;
  esac
}

# Surface 1 -- the batch table. -b -n1 takes ONE sample and prints the header
# block plus the column row (view_batch.c:38-52). Asserting the column header
# rather than a number keeps the case about "a parseable table was produced".
_o=$(iotop -b -n 1 </dev/null 2>&1); _r=$?
case "$_o" in *"DISK READ"*) _h=1 ;; *) _h=0 ;; esac
if [ "$_r" -eq 0 ] && [ "$_h" -eq 1 ]; then bst_ok iotop/batch-table
elif bst_execfail "$_o"; then bst_unrun iotop/batch-table "$_o"
else bst_notok iotop/batch-table "$(idiag "$_o"): rc=$_r want a 'DISK READ' column header -- got:'$(_bst_1line "$_o")'"; fi

# Surface 2 -- the ticket's own criterion: a process generating I/O appears in
# that table. ONE dd, backgrounded, not a respawn loop: this guest does not
# return memory on process exit (brintos/linux#21) and refuses to stage a large
# exec under fragmentation (brintos/linux#44), and it was a retry loop around a
# big exec that wedged the guest outright while 60-ckermit.test was being
# written.
#
# THE WRITER IS SIZED, AND REAPED, AGAINST TWO MEASURED FACTS. First, writes
# here are SLOW: a first draft wrote 256 MB and had not finished inside the
# suite's 300 s bound, which cost this file an `iotop/suite-timeout` and lost
# the case entirely. Second, `kill` DOES NOT DELIVER on this arm
# (brintos/linux#21), so `kill "$_wp"; wait "$_wp"` does not shorten anything --
# it waits out the whole transfer, which is exactly how the first draft spent
# the bound. 8 MB at 64k is enough writing to be sampled and completes on its
# own, and the reaper below is a BOUNDED POLL rather than a signal, so a writer
# that outlives its welcome costs this case a few seconds instead of the file.
_w=${TMPDIR:-/tmp}/bst-iotop.$$
dd if=/dev/zero of="$_w" bs=64k count=128 >/dev/null 2>&1 &
_wp=$!
_o=$(iotop -b -n 1 -P </dev/null 2>&1); _r=$?
_i=0; while kill -0 "$_wp" 2>/dev/null && [ "$_i" -lt 30 ]; do sleep 1; _i=$((_i+1)); done
rm -f "$_w"
case "$_o" in *"dd"*) _h=1 ;; *) _h=0 ;; esac
if [ "$_r" -eq 0 ] && [ "$_h" -eq 1 ]; then bst_ok iotop/batch-writer-visible
elif bst_execfail "$_o"; then bst_unrun iotop/batch-writer-visible "$_o"
else bst_notok iotop/batch-writer-visible "$(idiag "$_o"): rc=$_r want the writing 'dd' in the table -- got:'$(_bst_1line "$_o")'"; fi