# sysfsutils: libsysfs + the systool device/bus/class query utility.
#
# systool resolves the sysfs mount point by scanning /proc/mounts ONCE
# (sysfs_get_mnt_path -> setmntent("/proc/mounts")) and then reads sysfs
# directories. That single /proc read is in the reliable class on wasm32-hwjs:
# the procps tools that hang on brintos/linux#9 (top/vmstat/pgrep/sysctl) read
# dozens of /proc files per run, which is what trips the EINTR-not-restarted
# path. systool is therefore safe to execute here, unlike those.
. "$BST_LIB"
require systool sysfsutils/present

# -h prints usage on stdout and exits 0 from inside the getopt loop, BEFORE
# systool checks for a sysfs mount point -- so this case asserts the binary
# itself loads and runs even on an image where sysfs is absent.
check_out sysfsutils/usage "Usage: systool" systool -h

# Everything below needs sysfs actually mounted. systool's own failure mode is
# "Unable to find sysfs mount point!" on stderr with rc=1, so an unmounted /sys
# would otherwise show up as five identical rc=1 failures with no root cause.
# Assert the precondition once, explicitly, and skip the rest if it is missing.
if grep -q ' sysfs ' /proc/mounts 2>/dev/null; then
    bst_ok sysfsutils/sysfs-mounted
else
    bst_notok sysfsutils/sysfs-mounted "no sysfs line in /proc/mounts; systool can query nothing"
    for c in buses classes class-query; do
        bst_skip "sysfsutils/$c" "sysfs not mounted on /sys"
    done
    exit 0
fi

# With no bus/class/module argument systool runs show_default_info(), which
# lists the bus, class and root-device directories it finds under the sysfs
# mount. Both headers are unconditional once sysfs is readable.
check_out sysfsutils/buses   "Supported sysfs buses:"   systool
check_out sysfsutils/classes "Supported sysfs classes:" systool

# The ticket's acceptance check: systool -c lists a device class. The class is
# discovered at runtime rather than hard-coded -- the wasm32-hwjs kernel's
# device model is minimal and its class set is not a desktop kernel's, so
# naming e.g. "net" here would encode an assumption this image need not meet.
# show_sysfs_class() prints Class = "<name>" on stdout and returns 0.
cls=$(ls /sys/class 2>/dev/null | head -1)
if [ -n "$cls" ]; then
    check_out sysfsutils/class-query "Class = \"$cls\"" systool -c "$cls"
else
    bst_notok sysfsutils/class-query "/sys/class is empty -- kernel exposes no device class"
fi