Upgrade toybox to 827dfe3fe1bc9da2c215f54a5124fb0edcc9321c

This project was upgraded with external_updater.
Usage: tools/external_updater/updater.sh update toybox
For more info, check https://cs.android.com/android/platform/superproject/+/master:tools/external_updater/README.md

Test: TreeHugger
Change-Id: I9ab0bb64ac3c18fe9aba35862ca6e73d2eb15597

18 files changed, 345 insertions, 326 deletions

diff --git a/METADATA b/METADATA
index 70204fac..727a0aef 100644
--- a/METADATA
+++ b/METADATA
@@ -13,11 +13,11 @@ third_party {
     type: GIT
     value: "https://github.com/landley/toybox"
   }
-  version: "8626a6ac7dff93bf97f754c93c3e426ee5c6b1e0"
+  version: "827dfe3fe1bc9da2c215f54a5124fb0edcc9321c"
   license_type: UNENCUMBERED
   last_upgrade_date {
     year: 2023
     month: 4
-    day: 17
+    day: 18
   }
 }
diff --git a/Makefile b/Makefile
index f51cd48c..52f0851c 100644
--- a/Makefile
+++ b/Makefile
@@ -77,7 +77,7 @@ tests: toybox
 	scripts/test.sh
 
 root:
-	scripts/mkroot.sh $(MAKEFLAGS)
+	mkroot/mkroot.sh $(MAKEFLAGS)
 
 run_root:
 	cd root/"$${CROSS:-host}" && ./run-qemu.sh
diff --git a/android/device/generated/help.h b/android/device/generated/help.h
index d771c2f7..72a74f50 100644
--- a/android/device/generated/help.h
+++ b/android/device/generated/help.h
@@ -538,7 +538,7 @@
 
 #define HELP_time "usage: time [-pv] COMMAND...\n\nRun command line and report real, user, and system time elapsed in seconds.\n(real = clock on the wall, user = cpu used by command's code,\nsystem = cpu used by OS on behalf of command.)\n\n-p	POSIX format output\n-v	Verbose"
 
-#define HELP_test "usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]\n\nReturn true or false by performing tests. No arguments is false, one argument\nis true if not empty string.\n\n--- Tests with a single argument (after the option):\nPATH is/has:\n  -b  block device   -f  regular file   -p  fifo           -u  setuid bit\n  -c  char device    -g  setgid         -r  readable       -w  writable\n  -d  directory      -h  symlink        -S  socket         -x  executable\n  -e  exists         -L  symlink        -s  nonzero size   -k  sticky bit\nSTRING is:\n  -n  nonzero size   -z  zero size\nFD (integer file descriptor) is:\n  -t  a TTY\n\n--- Tests with one argument on each side of an operator:\nTwo strings:\n  =  are identical   !=  differ         =~  string matches regex\nAlphabetical sort:\n  <  first is lower  >   first higher\nTwo integers:\n  -eq  equal         -gt  first > second    -lt  first < second\n  -ne  not equal     -ge  first >= second   -le  first <= second\n\n--- Modify or combine tests:\n  ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)\n  ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)"
+#define HELP_test "usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]\n\nReturn true or false by performing tests. No arguments is false, one argument\nis true if not empty string.\n\n--- Tests with a single argument (after the option):\nPATH is/has:\n  -b  block device   -f  regular file   -p  fifo           -u  setuid bit\n  -c  char device    -g  setgid         -r  readable       -w  writable\n  -d  directory      -h  symlink        -S  socket         -x  executable\n  -e  exists         -L  symlink        -s  nonzero size   -k  sticky bit\nSTRING is:\n  -n  nonzero size   -z  zero size\nFD (integer file descriptor) is:\n  -t  a TTY          -T  open\n\n--- Tests with one argument on each side of an operator:\nTwo strings:\n  =  are identical   !=  differ         =~  string matches regex\nAlphabetical sort:\n  <  first is lower  >   first higher\nTwo integers:\n  -eq  equal         -gt  first > second    -lt  first < second\n  -ne  not equal     -ge  first >= second   -le  first <= second\n\n--- Modify or combine tests:\n  ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)\n  ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)"
 
 #define HELP_tee "usage: tee [-ai] [FILE...]\n\nCopy stdin to each listed file, and also to stdout.\nFilename \"-\" is a synonym for stdout.\n\n-a	Append to files\n-i	Ignore SIGINT"
 
diff --git a/android/linux/generated/help.h b/android/linux/generated/help.h
index c95b74a1..aef88284 100644
--- a/android/linux/generated/help.h
+++ b/android/linux/generated/help.h
@@ -540,7 +540,7 @@
 
 #define HELP_time "usage: time [-pv] COMMAND...\n\nRun command line and report real, user, and system time elapsed in seconds.\n(real = clock on the wall, user = cpu used by command's code,\nsystem = cpu used by OS on behalf of command.)\n\n-p	POSIX format output\n-v	Verbose"
 
-#define HELP_test "usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]\n\nReturn true or false by performing tests. No arguments is false, one argument\nis true if not empty string.\n\n--- Tests with a single argument (after the option):\nPATH is/has:\n  -b  block device   -f  regular file   -p  fifo           -u  setuid bit\n  -c  char device    -g  setgid         -r  readable       -w  writable\n  -d  directory      -h  symlink        -S  socket         -x  executable\n  -e  exists         -L  symlink        -s  nonzero size   -k  sticky bit\nSTRING is:\n  -n  nonzero size   -z  zero size\nFD (integer file descriptor) is:\n  -t  a TTY\n\n--- Tests with one argument on each side of an operator:\nTwo strings:\n  =  are identical   !=  differ         =~  string matches regex\nAlphabetical sort:\n  <  first is lower  >   first higher\nTwo integers:\n  -eq  equal         -gt  first > second    -lt  first < second\n  -ne  not equal     -ge  first >= second   -le  first <= second\n\n--- Modify or combine tests:\n  ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)\n  ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)"
+#define HELP_test "usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]\n\nReturn true or false by performing tests. No arguments is false, one argument\nis true if not empty string.\n\n--- Tests with a single argument (after the option):\nPATH is/has:\n  -b  block device   -f  regular file   -p  fifo           -u  setuid bit\n  -c  char device    -g  setgid         -r  readable       -w  writable\n  -d  directory      -h  symlink        -S  socket         -x  executable\n  -e  exists         -L  symlink        -s  nonzero size   -k  sticky bit\nSTRING is:\n  -n  nonzero size   -z  zero size\nFD (integer file descriptor) is:\n  -t  a TTY          -T  open\n\n--- Tests with one argument on each side of an operator:\nTwo strings:\n  =  are identical   !=  differ         =~  string matches regex\nAlphabetical sort:\n  <  first is lower  >   first higher\nTwo integers:\n  -eq  equal         -gt  first > second    -lt  first < second\n  -ne  not equal     -ge  first >= second   -le  first <= second\n\n--- Modify or combine tests:\n  ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)\n  ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)"
 
 #define HELP_tee "usage: tee [-ai] [FILE...]\n\nCopy stdin to each listed file, and also to stdout.\nFilename \"-\" is a synonym for stdout.\n\n-a	Append to files\n-i	Ignore SIGINT"
 
diff --git a/android/mac/generated/help.h b/android/mac/generated/help.h
index c95b74a1..aef88284 100644
--- a/android/mac/generated/help.h
+++ b/android/mac/generated/help.h
@@ -540,7 +540,7 @@
 
 #define HELP_time "usage: time [-pv] COMMAND...\n\nRun command line and report real, user, and system time elapsed in seconds.\n(real = clock on the wall, user = cpu used by command's code,\nsystem = cpu used by OS on behalf of command.)\n\n-p	POSIX format output\n-v	Verbose"
 
-#define HELP_test "usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]\n\nReturn true or false by performing tests. No arguments is false, one argument\nis true if not empty string.\n\n--- Tests with a single argument (after the option):\nPATH is/has:\n  -b  block device   -f  regular file   -p  fifo           -u  setuid bit\n  -c  char device    -g  setgid         -r  readable       -w  writable\n  -d  directory      -h  symlink        -S  socket         -x  executable\n  -e  exists         -L  symlink        -s  nonzero size   -k  sticky bit\nSTRING is:\n  -n  nonzero size   -z  zero size\nFD (integer file descriptor) is:\n  -t  a TTY\n\n--- Tests with one argument on each side of an operator:\nTwo strings:\n  =  are identical   !=  differ         =~  string matches regex\nAlphabetical sort:\n  <  first is lower  >   first higher\nTwo integers:\n  -eq  equal         -gt  first > second    -lt  first < second\n  -ne  not equal     -ge  first >= second   -le  first <= second\n\n--- Modify or combine tests:\n  ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)\n  ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)"
+#define HELP_test "usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]\n\nReturn true or false by performing tests. No arguments is false, one argument\nis true if not empty string.\n\n--- Tests with a single argument (after the option):\nPATH is/has:\n  -b  block device   -f  regular file   -p  fifo           -u  setuid bit\n  -c  char device    -g  setgid         -r  readable       -w  writable\n  -d  directory      -h  symlink        -S  socket         -x  executable\n  -e  exists         -L  symlink        -s  nonzero size   -k  sticky bit\nSTRING is:\n  -n  nonzero size   -z  zero size\nFD (integer file descriptor) is:\n  -t  a TTY          -T  open\n\n--- Tests with one argument on each side of an operator:\nTwo strings:\n  =  are identical   !=  differ         =~  string matches regex\nAlphabetical sort:\n  <  first is lower  >   first higher\nTwo integers:\n  -eq  equal         -gt  first > second    -lt  first < second\n  -ne  not equal     -ge  first >= second   -le  first <= second\n\n--- Modify or combine tests:\n  ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)\n  ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)"
 
 #define HELP_tee "usage: tee [-ai] [FILE...]\n\nCopy stdin to each listed file, and also to stdout.\nFilename \"-\" is a synonym for stdout.\n\n-a	Append to files\n-i	Ignore SIGINT"
 
diff --git a/mkroot/mkroot.sh b/mkroot/mkroot.sh
new file mode 100755
index 00000000..0447b386
--- /dev/null
+++ b/mkroot/mkroot.sh
@@ -0,0 +1,309 @@
+#!/bin/bash
+
+# ------------------------------ Part 1: Setup -------------------------------
+
+# Clear environment variables by restarting script w/bare minimum passed through
+[ -z "$NOCLEAR" ] && exec env -i NOCLEAR=1 HOME="$HOME" PATH="$PATH" \
+    LINUX="$LINUX" CROSS="$CROSS" CROSS_COMPILE="$CROSS_COMPILE" "$0" "$@"
+
+! [ -d mkroot ] && echo "Run mkroot/mkroot.sh from toybox source dir." && exit 1
+
+# assign command line NAME=VALUE args to env vars, the rest are packages
+for i in "$@"; do
+  [ "${i/=/}" != "$i" ] && export "$i" || { [ "$i" != -- ] && PKG="$PKG $i"; }
+done
+
+# Set default directory locations (overrideable from command line)
+: ${TOP:=$PWD/root} ${BUILD:=$TOP/build} ${LOG:=$BUILD/log}
+: ${AIRLOCK:=$BUILD/airlock} ${CCC:=$PWD/ccc} ${PKGDIR:=$PWD/mkroot/root}
+
+announce() { printf "\033]2;$CROSS $*\007" >/dev/tty; printf "\n=== $*\n";}
+die() { echo "$@" >&2; exit 1; }
+
+# ----- Are we cross compiling (via CROSS_COMPILE= or CROSS=)
+
+if [ -n "$CROSS_COMPILE" ]; then
+  # airlock needs absolute path
+  [ -z "${X:=$(command -v "$CROSS_COMPILE"cc)}" ] && die "no ${CROSS_COMPILE}cc"
+  CROSS_COMPILE="$(realpath -s "${X%cc}")"
+  [ -z "$CROSS" ] && CROSS=${CROSS_COMPILE/*\//} CROSS=${CROSS/-*/}
+
+elif [ -n "$CROSS" ]; then # CROSS=all/allnonstop/$ARCH else list known $ARCHes
+  [ ! -d "$CCC" ] && die "No ccc symlink to compiler directory."
+  TARGETS="$(ls "$CCC" | sed -n 's/-.*//p' | sort -u)"
+
+  if [ "${CROSS::3}" == all ]; then # loop calling ourselves for each target
+    for i in $TARGETS; do
+      "$0" "$@" CROSS=$i || [ "$CROSS" == allnonstop ] || exit 1
+    done; exit
+
+  else # Find matching cross compiler under ccc/ else list available targets
+    CROSS_COMPILE="$(echo "$CCC/$CROSS"-*cross/bin/"$CROSS"*-cc)" # wildcard
+    [ ! -e "$CROSS_COMPILE" ] && echo $TARGETS && exit # list available targets
+    CROSS_COMPILE="${CROSS_COMPILE%cc}" # trim to prefix for cc/ld/as/nm/strip
+  fi
+fi
+
+# Set per-target output directory (using "host" if not cross-compiling)
+: ${CROSS:=host} ${OUTPUT:=$TOP/$CROSS}
+
+# Verify selected compiler works
+${CROSS_COMPILE}cc --static -xc - -o /dev/null <<< "int main(void){return 0;}"||
+  die "${CROSS_COMPILE}cc can't create static binaries"
+
+# ----- Create hermetic build environment
+
+if [ -z "$NOAIRLOCK"] && [ -n "$CROSS_COMPILE" ]; then
+  # When cross compiling set host $PATH to binaries with known behavior by
+  # - building a host toybox later builds use as their command line
+  # - cherry-picking specific commands from old path via symlink
+  if [ ! -e "$AIRLOCK/toybox" ]; then
+    announce "airlock" &&
+    PREFIX="$AIRLOCK" KCONFIG_CONFIG=.singleconfig_airlock CROSS_COMPILE= \
+      make clean defconfig toybox install_airlock && # see scripts/install.sh
+    rm .singleconfig_airlock || exit 1
+  fi
+  export PATH="$AIRLOCK"
+  CPIO_OPTS+=--no-preserve-owner
+fi
+
+# Create per-target work directories
+TEMP="$BUILD/${CROSS}-tmp" && rm -rf "$TEMP" &&
+mkdir -p "$TEMP" "$OUTPUT" "$LOG" || exit 1
+[ -z "$ROOT" ] && ROOT="$OUTPUT/fs" && rm -rf "$ROOT"
+
+# ----- log build output
+
+# Install command line recording wrapper, logs all commands run from $PATH
+if [ -z "$NOLOGPATH" ]; then
+  # Move cross compiler into $PATH so calls to it get logged
+  [ -n "$CROSS_COMPILE" ] && PATH="${CROSS_COMPILE%/*}:$PATH" &&
+    CROSS_COMPILE=${CROSS_COMPILE##*/}
+  export WRAPDIR="$BUILD/record-commands" LOGPATH="$LOG/$CROSS-commands.txt"
+  rm -rf "$WRAPDIR" "$LOGPATH" generated/obj &&
+  WRAPDIR="$WRAPDIR" CROSS_COMPILE= NOSTRIP=1 source mkroot/record-commands ||
+    exit 1
+fi
+
+# Start logging stdout/stderr
+rm -f "$LOG/$CROSS".{n,y} || exit 1
+[ -z "$NOLOG" ] && exec > >(tee "$LOG/$CROSS.n") 2>&1
+echo "Building for $CROSS"
+
+# ---------------------- Part 2: Create root filesystem -----------------------
+
+# ----- Create new root filesystem's directory layout.
+
+# FHS wants boot media opt srv usr/{local,share}, stuff under /var...
+mkdir -p "$ROOT"/{dev,etc/rc,home,mnt,proc,root,sys,tmp/run,usr/{bin,sbin,lib},var} &&
+chmod a+rwxt "$ROOT"/tmp && ln -s usr/{bin,sbin,lib} tmp/run "$ROOT" || exit 1
+
+# Write init script. Runs as pid 1 from initramfs to set up and hand off system.
+cat > "$ROOT"/init << 'EOF' &&
+#!/bin/sh
+
+export HOME=/home PATH=/bin:/sbin
+
+if ! mountpoint -q dev; then
+  mount -t devtmpfs dev dev
+  [ $$ -eq 1 ] && exec 0<>/dev/console 1>&0 2>&1
+  for i in ,fd /0,stdin /1,stdout /2,stderr
+  do ln -sf /proc/self/fd${i/,*/} dev/${i/*,/}; done
+  mkdir -p dev/shm
+  chmod +t /dev/shm
+fi
+mountpoint -q dev/pts || { mkdir -p dev/pts && mount -t devpts dev/pts dev/pts;}
+mountpoint -q proc || mount -t proc proc proc
+mountpoint -q sys || mount -t sysfs sys sys
+echo 0 99999 > /proc/sys/net/ipv4/ping_group_range
+
+if [ $$ -eq 1 ]; then # Setup networking for QEMU (needs /proc)
+  mountpoint -q mnt || [ -e /dev/?da ] && mount /dev/?da /mnt
+  ifconfig lo 127.0.0.1
+  ifconfig eth0 10.0.2.15
+  route add default gw 10.0.2.2
+  [ "$(date +%s)" -lt 1000 ] && timeout 2 sntp -sq 10.0.2.2 # Ask host
+  [ "$(date +%s)" -lt 10000000 ] && sntp -sq time.google.com
+
+  # Run package scripts (if any)
+  for i in $(ls -1 /etc/rc 2>/dev/null | sort); do . /etc/rc/"$i"; done
+
+  [ -z "$HANDOFF" ] && [ -e /mnt/init ] && HANDOFF=/mnt/init
+  [ -z "$HANDOFF" ] && HANDOFF=/bin/sh && echo -e '\e[?7hType exit when done.'
+  echo 3 > /proc/sys/kernel/printk
+  exec oneit $HANDOFF
+else # for chroot
+  /bin/sh
+  umount /dev/pts /dev /sys /proc
+fi
+EOF
+chmod +x "$ROOT"/init &&
+
+# Google's nameserver, passwd+group with special (root/nobody) accounts + guest
+echo "nameserver 8.8.8.8" > "$ROOT"/etc/resolv.conf &&
+cat > "$ROOT"/etc/passwd << 'EOF' &&
+root:x:0:0:root:/root:/bin/sh
+guest:x:500:500:guest:/home/guest:/bin/sh
+nobody:x:65534:65534:nobody:/proc/self:/dev/null
+EOF
+echo -e 'root:x:0:\nguest:x:500:\nnobody:x:65534:' > "$ROOT"/etc/group || exit 1
+
+# Build any packages listed on command line
+for i in ${PKG:+plumbing $PKG}; do
+  pushd .
+  announce "$i"; PATH="$PKGDIR:$PATH" source $i || die $i
+  popd
+done
+
+# Build static toybox with existing .config if there is one, else defconfig+sh
+announce toybox
+[ -n "$PENDING" ] && rm -f .config
+[ -e .config ] && CONF=silentoldconfig || unset CONF
+for i in $PENDING sh route; do XX="$XX"$'\n'CONFIG_${i^^?}=y; done
+[ -e "$ROOT"/lib/libc.so ] || export LDFLAGS=--static
+PREFIX="$ROOT" make clean \
+  ${CONF:-defconfig KCONFIG_ALLCONFIG=<(echo "$XX")} toybox install || exit 1
+unset LDFLAGS
+
+# ------------------ Part 3: Build + package bootable system ------------------
+
+# Convert comma separated values in $1 to CONFIG=$2 lines
+csv2cfg() { sed -E '/^$/d;s/([^,]*)($|,)/CONFIG_\1='"$2"'\n/g' <<< "$1"; }
+
+# ----- Build kernel for target
+
+if [ -z "$LINUX" ] || [ ! -d "$LINUX/kernel" ]; then
+  echo 'No $LINUX directory, kernel build skipped.'
+else
+  # Which architecture are we building a kernel for?
+  LINUX="$(realpath "$LINUX")"
+  [ -z "$TARGET" ] &&
+    { [ "$CROSS" == host ] && TARGET="$(uname -m)" || TARGET="$CROSS"; }
+
+  # Target-specific info in an (alphabetical order) if/else staircase
+  # Each target needs board config, serial console, RTC, ethernet, block device.
+
+  if [ "$TARGET" == armv5l ]; then
+    # This could use the same VIRT board as armv7, but let's demonstrate a
+    # different one requiring a separate device tree binary.
+    QEMU="arm -M versatilepb -net nic,model=rtl8139 -net user"
+    KARCH=arm KARGS=ttyAMA0 VMLINUX=arch/arm/boot/zImage
+    KCONF=CPU_ARM926T,MMU,VFP,ARM_THUMB,AEABI,ARCH_VERSATILE,ATAGS,DEPRECATED_PARAM_STRUCT,ARM_ATAG_DTB_COMPAT,ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND,SERIAL_AMBA_PL011,SERIAL_AMBA_PL011_CONSOLE,RTC_CLASS,RTC_DRV_PL031,RTC_HCTOSYS,PCI,PCI_VERSATILE,BLK_DEV_SD,SCSI,SCSI_LOWLEVEL,SCSI_SYM53C8XX_2,SCSI_SYM53C8XX_MMIO,NET_VENDOR_REALTEK,8139CP
+    KERNEL_CONFIG="CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=0"
+    DTB=arch/arm/boot/dts/versatile-pb.dtb
+  elif [ "$TARGET" == armv7l ] || [ "$TARGET" == aarch64 ]; then
+    if [ "$TARGET" == aarch64 ]; then
+      QEMU="aarch64 -M virt -cpu cortex-a57"
+      KARCH=arm64 VMLINUX=arch/arm64/boot/Image
+    else
+      QEMU="arm -M virt" KARCH=arm VMLINUX=arch/arm/boot/zImage
+    fi
+    KARGS=ttyAMA0
+    KCONF=MMU,ARCH_MULTI_V7,ARCH_VIRT,SOC_DRA7XX,ARCH_OMAP2PLUS_TYPICAL,ARCH_ALPINE,ARM_THUMB,VDSO,CPU_IDLE,ARM_CPUIDLE,KERNEL_MODE_NEON,SERIAL_AMBA_PL011,SERIAL_AMBA_PL011_CONSOLE,RTC_CLASS,RTC_HCTOSYS,RTC_DRV_PL031,NET_CORE,VIRTIO_MENU,VIRTIO_NET,PCI,PCI_HOST_GENERIC,VIRTIO_BLK,VIRTIO_PCI,VIRTIO_MMIO,ATA,ATA_SFF,ATA_BMDMA,ATA_PIIX,PATA_PLATFORM,PATA_OF_PLATFORM,ATA_GENERIC,ARM_LPAE
+  elif [ "$TARGET" == hexagon ]; then
+    QEMU="hexagon -M comet" KARGS=ttyS0 VMLINUX=vmlinux
+    KARCH="hexagon LLVM_IAS=1" KCONF=SPI,SPI_BITBANG,IOMMU_SUPPORT
+  elif [ "$TARGET" == i486 ] || [ "$TARGET" == i686 ] ||
+       [ "$TARGET" == x86_64 ] || [ "$TARGET" == x32 ]; then
+    if [ "$TARGET" == i486 ]; then
+      QEMU="i386 -cpu 486 -global fw_cfg.dma_enabled=false" KCONF=M486
+    elif [ "$TARGET" == i686 ]; then
+      QEMU="i386 -cpu pentium3" KCONF=MPENTIUMII
+    else
+      QEMU=x86_64 KCONF=64BIT
+      [ "$TARGET" == x32 ] && KCONF=X86_X32
+    fi
+    KARCH=x86 KARGS=ttyS0 VMLINUX=arch/x86/boot/bzImage
+    KCONF=$KCONF,UNWINDER_FRAME_POINTER,PCI,BLK_DEV_SD,ATA,ATA_SFF,ATA_BMDMA,ATA_PIIX,NET_VENDOR_INTEL,E1000,SERIAL_8250,SERIAL_8250_CONSOLE,RTC_CLASS
+  elif [ "$TARGET" == m68k ]; then
+    QEMU="m68k -M q800" KARCH=m68k KARGS=ttyS0 VMLINUX=vmlinux
+    KCONF=MMU,M68040,M68KFPU_EMU,MAC,SCSI,SCSI_LOWLEVEL,BLK_DEV_SD,SCSI_MAC_ESP,MACINTOSH_DRIVERS,NET_CORE,NET_VENDOR_NATSEMI,MACSONIC,SERIAL_PMACZILOG,SERIAL_PMACZILOG_TTYS,SERIAL_PMACZILOG_CONSOLE
+  elif [ "$TARGET" == mips ] || [ "$TARGET" == mipsel ]; then
+    QEMU="mips -M malta" KARCH=mips KARGS=ttyS0 VMLINUX=vmlinux
+    KCONF=MIPS_MALTA,CPU_MIPS32_R2,SERIAL_8250,SERIAL_8250_CONSOLE,PCI,BLK_DEV_SD,ATA,ATA_SFF,ATA_BMDMA,ATA_PIIX,NET_VENDOR_AMD,PCNET32,POWER_RESET,POWER_RESET_SYSCON
+    [ "$TARGET" == mipsel ] && KCONF=$KCONF,CPU_LITTLE_ENDIAN &&
+      QEMU="mipsel -M malta"
+  elif [ "$TARGET" == powerpc ]; then
+    KARCH=powerpc QEMU="ppc -M g3beige" KARGS=ttyS0 VMLINUX=vmlinux
+    KCONF=ALTIVEC,PPC_PMAC,PPC_OF_BOOT_TRAMPOLINE,ATA,ATA_SFF,ATA_BMDMA,PATA_MACIO,BLK_DEV_SD,MACINTOSH_DRIVERS,ADB,ADB_CUDA,NET_VENDOR_NATSEMI,NET_VENDOR_8390,NE2K_PCI,SERIO,SERIAL_PMACZILOG,SERIAL_PMACZILOG_TTYS,SERIAL_PMACZILOG_CONSOLE,BOOTX_TEXT
+  elif [ "$TARGET" == powerpc64 ] || [ "$TARGET" == powerpc64le ]; then
+    KARCH=powerpc QEMU="ppc64 -M pseries -vga none" KARGS=hvc0
+    VMLINUX=vmlinux
+    KCONF=PPC64,PPC_PSERIES,PPC_OF_BOOT_TRAMPOLINE,BLK_DEV_SD,SCSI_LOWLEVEL,SCSI_IBMVSCSI,ATA,NET_VENDOR_IBM,IBMVETH,HVC_CONSOLE,PPC_TRANSACTIONAL_MEM,PPC_DISABLE_WERROR,SECTION_MISMATCH_WARN_ONLY
+    [ "$TARGET" == powerpc64le ] && KCONF=$KCONF,CPU_LITTLE_ENDIAN
+  elif [ "$TARGET" = s390x ]; then
+    QEMU="s390x" KARCH=s390 VMLINUX=arch/s390/boot/bzImage
+    KCONF=MARCH_Z900,PACK_STACK,NET_CORE,VIRTIO_NET,VIRTIO_BLK,SCLP_TTY,SCLP_CONSOLE,SCLP_VT220_TTY,SCLP_VT220_CONSOLE,S390_GUEST
+  elif [ "$TARGET" == sh2eb ]; then
+    BUILTIN=1 KARCH=sh VMLINUX=vmlinux
+    KERNEL_CONFIG=$'CONFIG_MEMORY_START=0x10000000\nCONFIG_CMDLINE="console=ttyUL0 earlycon"'
+    KCONF=CPU_SUBTYPE_J2,CPU_BIG_ENDIAN,SH_JCORE_SOC,SMP,BINFMT_ELF_FDPIC,JCORE_EMAC,SERIAL_UARTLITE,SERIAL_UARTLITE_CONSOLE,HZ_100,CMDLINE_OVERWRITE,SPI,SPI_JCORE,MMC,PWRSEQ_SIMPLE,MMC_BLOCK,MMC_SPI
+  elif [ "$TARGET" == sh4 ]; then
+    QEMU="sh4 -M r2d -serial null -serial mon:stdio" KARCH=sh
+    KARGS="ttySC1 noiotrap" VMLINUX=arch/sh/boot/zImage
+    KERNEL_CONFIG="CONFIG_MEMORY_START=0x0c000000"
+    KCONF=CPU_SUBTYPE_SH7751R,MMU,VSYSCALL,SH_FPU,SH_RTS7751R2D,RTS7751R2D_PLUS,SERIAL_SH_SCI,SERIAL_SH_SCI_CONSOLE,PCI,NET_VENDOR_REALTEK,8139CP,PCI,BLK_DEV_SD,ATA,ATA_SFF,ATA_BMDMA,PATA_PLATFORM,BINFMT_ELF_FDPIC,BINFMT_FLAT
+#see also SPI SPI_SH_SCI MFD_SM501 RTC_CLASS RTC_DRV_R9701 RTC_DRV_SH RTC_HCTOSYS
+  else die "Unknown \$TARGET $TARGET"
+  fi
+
+  # Write the qemu launch script
+  if [ -n "$QEMU" ]; then
+    [ -z "$BUILTIN" ] && INITRD="-initrd initramfs.cpio.gz"
+    { echo qemu-system-"$QEMU" '"$@"' $QEMU_MORE -nographic -no-reboot -m 256 \
+        -kernel linux-kernel $INITRD ${DTB:+-dtb linux.dtb} \
+        "-append \"panic=1 HOST=$TARGET console=$KARGS \$KARGS\"" &&
+      echo "echo -e '\\e[?7h'"
+    } > "$OUTPUT"/run-qemu.sh &&
+    chmod +x "$OUTPUT"/run-qemu.sh || exit 1
+  fi
+
+  announce "linux-$KARCH"
+  pushd "$LINUX" && make distclean && popd &&
+  cp -sfR "$LINUX" "$TEMP/linux" && pushd "$TEMP/linux" &&
+
+  # Write linux-miniconfig
+  { echo "# make ARCH=$KARCH allnoconfig KCONFIG_ALLCONFIG=linux-miniconfig"
+    echo -e "# make ARCH=$KARCH -j \$(nproc)\n# boot $VMLINUX\n\n"
+
+    # Expand list of =y symbols, first generic then architecture-specific
+    for i in BINFMT_ELF,BINFMT_SCRIPT,NO_HZ,HIGH_RES_TIMERS,BLK_DEV,BLK_DEV_INITRD,RD_GZIP,BLK_DEV_LOOP,EXT4_FS,EXT4_USE_FOR_EXT2,VFAT_FS,FAT_DEFAULT_UTF8,MISC_FILESYSTEMS,SQUASHFS,SQUASHFS_XATTR,SQUASHFS_ZLIB,DEVTMPFS,DEVTMPFS_MOUNT,TMPFS,TMPFS_POSIX_ACL,NET,PACKET,UNIX,INET,IPV6,NETDEVICES,NET_CORE,NETCONSOLE,ETHERNET,COMPAT_32BIT_TIME,EARLY_PRINTK,IKCONFIG,IKCONFIG_PROC $KCONF $KEXTRA ; do
+      echo "# architecture ${X:-independent}"
+      csv2cfg "$i" y
+      X=specific
+    done
+    [ -n "$BUILTIN" ] && echo -e CONFIG_INITRAMFS_SOURCE="\"$OUTPUT/fs\""
+    for i in $MODULES; do csv2cfg "$i" m; done
+    echo "$KERNEL_CONFIG"
+  } > "$OUTPUT/linux-miniconfig" &&
+  make ARCH=$KARCH allnoconfig KCONFIG_ALLCONFIG="$OUTPUT/linux-miniconfig" &&
+
+  # Second config pass to remove stupid kernel defaults
+  # See http://lkml.iu.edu/hypermail/linux/kernel/1912.3/03493.html
+  sed -e 's/# CONFIG_EXPERT .*/CONFIG_EXPERT=y/' -e "$(sed -E -e '/^$/d' \
+    -e 's@([^,]*)($|,)@/^CONFIG_\1=y/d;$a# CONFIG_\1 is not set\n@g' \
+       <<< VT,SCHED_DEBUG,DEBUG_MISC,X86_DEBUG_FPU)" -i .config &&
+  yes "" | make ARCH=$KARCH oldconfig > /dev/null &&
+  cp .config "$OUTPUT/linux-fullconfig" &&
+
+  # Build kernel. Copy config, device tree binary, and kernel binary to output
+  make ARCH=$KARCH CROSS_COMPILE="$CROSS_COMPILE" -j $(nproc) all || exit 1
+  [ -n "$DTB" ] && { cp "$DTB" "$OUTPUT/linux.dtb" || exit 1 ;}
+  if [ -n "$MODULES" ]; then
+    make ARCH=$KARCH INSTALL_MOD_PATH=modz modules_install &&
+      (cd modz && find lib/modules | cpio -o -H newc $CPIO_OPTS ) | gzip \
+       > "$OUTPUT/modules.cpio.gz" || exit 1
+  fi
+  cp "$VMLINUX" "$OUTPUT"/linux-kernel && cd .. && rm -rf linux && popd ||exit 1
+fi
+
+# clean up and package root filesystem for initramfs.
+if [ -z "$BUILTIN" ]; then
+  announce initramfs
+  { (cd "$ROOT" && find . | cpio -o -H newc $CPIO_OPTS ) || exit 1
+    ! test -e "$OUTPUT/modules.cpio.gz" || zcat $_;} | gzip \
+    > "$OUTPUT"/initramfs.cpio.gz || exit 1
+fi
+
+mv "$LOG/$CROSS".{n,y} && echo "Output is in $OUTPUT"
+rmdir "$TEMP" "$BUILD" 2>/dev/null || exit 0 # remove if empty, not an error
diff --git a/scripts/record-commands b/mkroot/record-commands
index d2b779fa..d2b779fa 100755
--- a/scripts/record-commands
+++ b/mkroot/record-commands
diff --git a/scripts/root/dropbear b/mkroot/root/dropbear
index cd0b1578..9a4adcb8 100755
--- a/scripts/root/dropbear
+++ b/mkroot/root/dropbear
@@ -1,4 +1,4 @@
-#!/bin/echo Try "scripts/mkroot.sh dropbear"
+#!/bin/echo Try "mkroot/mkroot.sh dropbear"
 
 # Example overlay file, adding dropbear (which requires zlib)
 
diff --git a/scripts/root/dynamic b/mkroot/root/dynamic
index c82b1ddb..2ecfbdaa 100755
--- a/scripts/root/dynamic
+++ b/mkroot/root/dynamic
@@ -1,4 +1,4 @@
-#!/bin/echo Try "scripts/mkroot.sh dynamic"
+#!/bin/echo Try "mkroot/mkroot.sh dynamic"
 
 # Copy dynamic libraries from cross compiler
 
diff --git a/mkroot/root/overlay b/mkroot/root/overlay
new file mode 100755
index 00000000..be0aaede
--- /dev/null
+++ b/mkroot/root/overlay
@@ -0,0 +1,3 @@
+#!/bin/echo Try "mkroot/mkroot.sh overlay"
+
+cp -a "${OVERLAY:=overlay}"/. "$ROOT"/.
diff --git a/scripts/root/plumbing b/mkroot/root/plumbing
index e72247c0..e72247c0 100755
--- a/scripts/root/plumbing
+++ b/mkroot/root/plumbing
diff --git a/scripts/root/tests b/mkroot/root/tests
index 89186d83..bca3b40c 100755
--- a/scripts/root/tests
+++ b/mkroot/root/tests
@@ -1,4 +1,4 @@
-#!/bin/echo Try "scripts/mkroot.sh $0"
+#!/bin/echo Try "mkroot/mkroot.sh $0"
 
 # Alas http://www.linux-usb.org/usb.ids is not versioned, so...
 download 36d4e16755502fbc684be75e56841e1014e4a94a \
diff --git a/scripts/test_mkroot.sh b/mkroot/testroot.sh
index e2679b1d..0e3f4494 100755
--- a/scripts/test_mkroot.sh
+++ b/mkroot/testroot.sh
@@ -1,5 +1,20 @@
 #!/bin/bash
 
+# usage: mkroot/testroot.sh [TARGET...]
+#
+# Test system image(s) (by booting qemu with -hda test.img providing /mnt/init)
+# and check that:
+#
+# A) it boots and runs our code (which means /dev/hda works)
+# B) the clock is set sanely ("make" is unhappy when source newer than output)
+# C) it can talk to the virtual network
+#
+# Each successful test prints a === line, and all 3 means it passed.
+# Writes result into root/build/test/$TARGET-test.txt
+#
+# With arguments, tests those targets (verbosely). With no arguments, tests
+# each target with a linux-kernel (in parallel) and prints pass/fail summary.
+
 die() { echo "$@"; exit 1; }
 
 [ -n "$(which toybox)" -a -n "$(which mksquashfs)" ] ||
@@ -7,7 +22,7 @@ die() { echo "$@"; exit 1; }
 
 mkdir -p "${TEST:=$PWD/root/build/test}" &&
 
-# Setup test filesystem
+# Setup test filesystem and package it into a squashfs.
 cat > "$TEST"/init << 'EOF' &&
 #!/bin/sh
 
@@ -21,7 +36,7 @@ chmod +x "$TEST"/init &&
 
 mksquashfs "$TEST"/init configure scripts/ tests/ "$TEST"/init.sqf -noappend -all-root >/dev/null &&
 
-# Setup for network smoke test
+# Setup server on host's loopback for network smoke test
 echo === net ok > "$TEST"/index.html || die "smoketest setup"
 toybox netcat -p 65432 -s 127.0.0.1 -L toybox httpd "$TEST" &
 trap "kill $!" EXIT
diff --git a/scripts/mkroot.sh b/scripts/mkroot.sh
index 60433240..2ac634bc 100755
--- a/scripts/mkroot.sh
+++ b/scripts/mkroot.sh
@@ -1,308 +1 @@
-#!/bin/bash
-
-# ------------------------------ Part 1: Setup -------------------------------
-
-# Clear environment variables by restarting script w/bare minimum passed through
-[ -z "$NOCLEAR" ] && exec env -i NOCLEAR=1 HOME="$HOME" PATH="$PATH" \
-    LINUX="$LINUX" CROSS="$CROSS" CROSS_COMPILE="$CROSS_COMPILE" "$0" "$@"
-
-# assign command line NAME=VALUE args to env vars, the rest are packages
-for i in "$@"; do
-  [ "${i/=/}" != "$i" ] && export "$i" || { [ "$i" != -- ] && PKG="$PKG $i"; }
-done
-
-# Set default directory locations (overrideable from command line)
-: ${TOP:=$PWD/root} ${BUILD:=$TOP/build} ${LOG:=$BUILD/log}
-: ${AIRLOCK:=$BUILD/airlock} ${CCC:=$PWD/ccc} ${PKGDIR:=$PWD/scripts/root}
-
-# define functions
-announce() { printf "\033]2;$CROSS $*\007" >/dev/tty; printf "\n=== $*\n";}
-die() { echo "$@" >&2; exit 1; }
-
-# ----- Are we cross compiling (via CROSS_COMPILE= or CROSS=)
-
-if [ -n "$CROSS_COMPILE" ]; then
-  # airlock needs absolute path
-  [ -z "${X:=$(command -v "$CROSS_COMPILE"cc)}" ] && die "no ${CROSS_COMPILE}cc"
-  CROSS_COMPILE="$(realpath -s "${X%cc}")"
-  [ -z "$CROSS" ] && CROSS=${CROSS_COMPILE/*\//} CROSS=${CROSS/-*/}
-
-elif [ -n "$CROSS" ]; then # CROSS=all/allnonstop/$ARCH else list known $ARCHes
-  [ ! -d "$CCC" ] && die "No ccc symlink to compiler directory."
-  TARGETS="$(ls "$CCC" | sed -n 's/-.*//p' | sort -u)"
-
-  if [ "${CROSS::3}" == all ]; then # loop calling ourselves for each target
-    for i in $TARGETS; do
-      "$0" "$@" CROSS=$i || [ "$CROSS" == allnonstop ] || exit 1
-    done; exit
-
-  else # Find matching cross compiler under ccc/ else list available targets
-    CROSS_COMPILE="$(echo "$CCC/$CROSS"-*cross/bin/"$CROSS"*-cc)" # wildcard
-    [ ! -e "$CROSS_COMPILE" ] && echo $TARGETS && exit # list available targets
-    CROSS_COMPILE="${CROSS_COMPILE%cc}" # trim to prefix for cc/ld/as/nm/strip
-  fi
-fi
-
-# Set per-target output directory (using "host" if not cross-compiling)
-: ${CROSS:=host} ${OUTPUT:=$TOP/$CROSS}
-
-# Verify selected compiler works
-${CROSS_COMPILE}cc --static -xc - -o /dev/null <<< "int main(void){return 0;}"||
-  die "${CROSS_COMPILE}cc can't create static binaries"
-
-# ----- Create hermetic build environment
-
-if [ -z "$NOAIRLOCK"] && [ -n "$CROSS_COMPILE" ]; then
-  # When cross compiling set host $PATH to binaries with known behavior by
-  # - building a host toybox later builds use as their command line
-  # - cherry-picking specific commands from old path via symlink
-  if [ ! -e "$AIRLOCK/toybox" ]; then
-    announce "airlock" &&
-    PREFIX="$AIRLOCK" KCONFIG_CONFIG=.singleconfig_airlock CROSS_COMPILE= \
-      make clean defconfig toybox install_airlock && # see scripts/install.sh
-    rm .singleconfig_airlock || exit 1
-  fi
-  export PATH="$AIRLOCK"
-  CPIO_OPTS+=--no-preserve-owner
-fi
-
-# Create per-target work directories
-TEMP="$BUILD/${CROSS}-tmp" && rm -rf "$TEMP" &&
-mkdir -p "$TEMP" "$OUTPUT" "$LOG" || exit 1
-[ -z "$ROOT" ] && ROOT="$OUTPUT/fs" && rm -rf "$ROOT"
-
-# ----- log build output
-
-# Install command line recording wrapper, logs all commands run from $PATH
-if [ -z "$NOLOGPATH" ]; then
-  # Move cross compiler into $PATH so calls to it get logged
-  [ -n "$CROSS_COMPILE" ] && PATH="${CROSS_COMPILE%/*}:$PATH" &&
-    CROSS_COMPILE=${CROSS_COMPILE##*/}
-  export WRAPDIR="$BUILD/record-commands" LOGPATH="$LOG/$CROSS-commands.txt"
-  rm -rf "$WRAPDIR" "$LOGPATH" generated/obj &&
-  WRAPDIR="$WRAPDIR" CROSS_COMPILE= NOSTRIP=1 source scripts/record-commands ||
-    exit 1
-fi
-
-# Start logging stdout/stderr
-rm -f "$LOG/$CROSS".{n,y} || exit 1
-[ -z "$NOLOG" ] && exec > >(tee "$LOG/$CROSS.n") 2>&1
-echo "Building for $CROSS"
-
-# ---------------------- Part 2: Create root filesystem -----------------------
-
-# ----- Create new root filesystem's directory layout.
-
-# FHS wants boot media opt srv usr/{local,share}, stuff under /var...
-mkdir -p "$ROOT"/{dev,etc/rc,home,mnt,proc,root,sys,tmp/run,usr/{bin,sbin,lib},var} &&
-chmod a+rwxt "$ROOT"/tmp && ln -s usr/{bin,sbin,lib} tmp/run "$ROOT" || exit 1
-
-# Write init script. Runs as pid 1 from initramfs to set up and hand off system.
-cat > "$ROOT"/init << 'EOF' &&
-#!/bin/sh
-
-export HOME=/home PATH=/bin:/sbin
-
-if ! mountpoint -q dev; then
-  mount -t devtmpfs dev dev
-  [ $$ -eq 1 ] && exec 0<>/dev/console 1>&0 2>&1
-  for i in ,fd /0,stdin /1,stdout /2,stderr
-  do ln -sf /proc/self/fd${i/,*/} dev/${i/*,/}; done
-  mkdir -p dev/shm
-  chmod +t /dev/shm
-fi
-mountpoint -q dev/pts || { mkdir -p dev/pts && mount -t devpts dev/pts dev/pts;}
-mountpoint -q proc || mount -t proc proc proc
-mountpoint -q sys || mount -t sysfs sys sys
-echo 0 99999 > /proc/sys/net/ipv4/ping_group_range
-
-if [ $$ -eq 1 ]; then # Setup networking for QEMU (needs /proc)
-  mountpoint -q mnt || [ -e /dev/?da ] && mount /dev/?da /mnt
-  ifconfig lo 127.0.0.1
-  ifconfig eth0 10.0.2.15
-  route add default gw 10.0.2.2
-  [ "$(date +%s)" -lt 1000 ] && timeout 2 sntp -sq 10.0.2.2 # Ask host
-  [ "$(date +%s)" -lt 10000000 ] && sntp -sq time.google.com
-
-  # Run package scripts (if any)
-  for i in $(ls -1 /etc/rc 2>/dev/null | sort); do . /etc/rc/"$i"; done
-
-  [ -z "$HANDOFF" ] && [ -e /mnt/init ] && HANDOFF=/mnt/init
-  [ -z "$HANDOFF" ] && HANDOFF=/bin/sh && echo -e '\e[?7hType exit when done.'
-  echo 3 > /proc/sys/kernel/printk
-  exec oneit $HANDOFF
-else # for chroot
-  /bin/sh
-  umount /dev/pts /dev /sys /proc
-fi
-EOF
-chmod +x "$ROOT"/init &&
-
-# Google's nameserver, passwd+group with special (root/nobody) accounts + guest
-echo "nameserver 8.8.8.8" > "$ROOT"/etc/resolv.conf &&
-cat > "$ROOT"/etc/passwd << 'EOF' &&
-root:x:0:0:root:/root:/bin/sh
-guest:x:500:500:guest:/home/guest:/bin/sh
-nobody:x:65534:65534:nobody:/proc/self:/dev/null
-EOF
-echo -e 'root:x:0:\nguest:x:500:\nnobody:x:65534:' > "$ROOT"/etc/group || exit 1
-
-# Build any packages listed on command line
-for i in ${PKG:+plumbing $PKG}; do
-  pushd .
-  announce "$i"; PATH="$PKGDIR:$PATH" source $i || die $i
-  popd
-done
-
-# Build static toybox with existing .config if there is one, else defconfig+sh
-announce toybox
-[ -n "$PENDING" ] && rm -f .config
-[ -e .config ] && CONF=silentoldconfig || unset CONF
-for i in $PENDING sh route; do XX="$XX"$'\n'CONFIG_${i^^?}=y; done
-[ -e "$ROOT"/lib/libc.so ] || export LDFLAGS=--static
-PREFIX="$ROOT" make clean \
-  ${CONF:-defconfig KCONFIG_ALLCONFIG=<(echo "$XX")} toybox install || exit 1
-unset LDFLAGS
-
-# ------------------ Part 3: Build + package bootable system ------------------
-
-# Convert comma separated values in $1 to CONFIG=$2 lines
-csv2cfg() { sed -E '/^$/d;s/([^,]*)($|,)/CONFIG_\1='"$2"'\n/g' <<< "$1"; }
-
-# ----- Build kernel for target
-
-if [ -z "$LINUX" ] || [ ! -d "$LINUX/kernel" ]; then
-  echo 'No $LINUX directory, kernel build skipped.'
-else
-  # Which architecture are we building a kernel for?
-  LINUX="$(realpath "$LINUX")"
-  [ -z "$TARGET" ] &&
-    { [ "$CROSS" == host ] && TARGET="$(uname -m)" || TARGET="$CROSS"; }
-
-  # Target-specific info in an (alphabetical order) if/else staircase
-  # Each target needs board config, serial console, RTC, ethernet, block device.
-
-  if [ "$TARGET" == armv5l ]; then
-    # This could use the same VIRT board as armv7, but let's demonstrate a
-    # different one requiring a separate device tree binary.
-    QEMU="arm -M versatilepb -net nic,model=rtl8139 -net user"
-    KARCH=arm KARGS=ttyAMA0 VMLINUX=arch/arm/boot/zImage
-    KCONF=CPU_ARM926T,MMU,VFP,ARM_THUMB,AEABI,ARCH_VERSATILE,ATAGS,DEPRECATED_PARAM_STRUCT,ARM_ATAG_DTB_COMPAT,ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND,SERIAL_AMBA_PL011,SERIAL_AMBA_PL011_CONSOLE,RTC_CLASS,RTC_DRV_PL031,RTC_HCTOSYS,PCI,PCI_VERSATILE,BLK_DEV_SD,SCSI,SCSI_LOWLEVEL,SCSI_SYM53C8XX_2,SCSI_SYM53C8XX_MMIO,NET_VENDOR_REALTEK,8139CP
-    KERNEL_CONFIG="CONFIG_SCSI_SYM53C8XX_DMA_ADDRESSING_MODE=0"
-    DTB=arch/arm/boot/dts/versatile-pb.dtb
-  elif [ "$TARGET" == armv7l ] || [ "$TARGET" == aarch64 ]; then
-    if [ "$TARGET" == aarch64 ]; then
-      QEMU="aarch64 -M virt -cpu cortex-a57"
-      KARCH=arm64 VMLINUX=arch/arm64/boot/Image
-    else
-      QEMU="arm -M virt" KARCH=arm VMLINUX=arch/arm/boot/zImage
-    fi
-    KARGS=ttyAMA0
-    KCONF=MMU,ARCH_MULTI_V7,ARCH_VIRT,SOC_DRA7XX,ARCH_OMAP2PLUS_TYPICAL,ARCH_ALPINE,ARM_THUMB,VDSO,CPU_IDLE,ARM_CPUIDLE,KERNEL_MODE_NEON,SERIAL_AMBA_PL011,SERIAL_AMBA_PL011_CONSOLE,RTC_CLASS,RTC_HCTOSYS,RTC_DRV_PL031,NET_CORE,VIRTIO_MENU,VIRTIO_NET,PCI,PCI_HOST_GENERIC,VIRTIO_BLK,VIRTIO_PCI,VIRTIO_MMIO,ATA,ATA_SFF,ATA_BMDMA,ATA_PIIX,PATA_PLATFORM,PATA_OF_PLATFORM,ATA_GENERIC,ARM_LPAE
-  elif [ "$TARGET" == hexagon ]; then
-    QEMU="hexagon -M comet" KARGS=ttyS0 VMLINUX=vmlinux
-    KARCH="hexagon LLVM_IAS=1" KCONF=SPI,SPI_BITBANG,IOMMU_SUPPORT
-  elif [ "$TARGET" == i486 ] || [ "$TARGET" == i686 ] ||
-       [ "$TARGET" == x86_64 ] || [ "$TARGET" == x32 ]; then
-    if [ "$TARGET" == i486 ]; then
-      QEMU="i386 -cpu 486 -global fw_cfg.dma_enabled=false" KCONF=M486
-    elif [ "$TARGET" == i686 ]; then
-      QEMU="i386 -cpu pentium3" KCONF=MPENTIUMII
-    else
-      QEMU=x86_64 KCONF=64BIT
-      [ "$TARGET" == x32 ] && KCONF=X86_X32
-    fi
-    KARCH=x86 KARGS=ttyS0 VMLINUX=arch/x86/boot/bzImage
-    KCONF=$KCONF,UNWINDER_FRAME_POINTER,PCI,BLK_DEV_SD,ATA,ATA_SFF,ATA_BMDMA,ATA_PIIX,NET_VENDOR_INTEL,E1000,SERIAL_8250,SERIAL_8250_CONSOLE,RTC_CLASS
-  elif [ "$TARGET" == m68k ]; then
-    QEMU="m68k -M q800" KARCH=m68k KARGS=ttyS0 VMLINUX=vmlinux
-    KCONF=MMU,M68040,M68KFPU_EMU,MAC,SCSI,SCSI_LOWLEVEL,BLK_DEV_SD,SCSI_MAC_ESP,MACINTOSH_DRIVERS,NET_CORE,NET_VENDOR_NATSEMI,MACSONIC,SERIAL_PMACZILOG,SERIAL_PMACZILOG_TTYS,SERIAL_PMACZILOG_CONSOLE
-  elif [ "$TARGET" == mips ] || [ "$TARGET" == mipsel ]; then
-    QEMU="mips -M malta" KARCH=mips KARGS=ttyS0 VMLINUX=vmlinux
-    KCONF=MIPS_MALTA,CPU_MIPS32_R2,SERIAL_8250,SERIAL_8250_CONSOLE,PCI,BLK_DEV_SD,ATA,ATA_SFF,ATA_BMDMA,ATA_PIIX,NET_VENDOR_AMD,PCNET32,POWER_RESET,POWER_RESET_SYSCON
-    [ "$TARGET" == mipsel ] && KCONF=$KCONF,CPU_LITTLE_ENDIAN &&
-      QEMU="mipsel -M malta"
-  elif [ "$TARGET" == powerpc ]; then
-    KARCH=powerpc QEMU="ppc -M g3beige" KARGS=ttyS0 VMLINUX=vmlinux
-    KCONF=ALTIVEC,PPC_PMAC,PPC_OF_BOOT_TRAMPOLINE,ATA,ATA_SFF,ATA_BMDMA,PATA_MACIO,BLK_DEV_SD,MACINTOSH_DRIVERS,ADB,ADB_CUDA,NET_VENDOR_NATSEMI,NET_VENDOR_8390,NE2K_PCI,SERIO,SERIAL_PMACZILOG,SERIAL_PMACZILOG_TTYS,SERIAL_PMACZILOG_CONSOLE,BOOTX_TEXT
-  elif [ "$TARGET" == powerpc64 ] || [ "$TARGET" == powerpc64le ]; then
-    KARCH=powerpc QEMU="ppc64 -M pseries -vga none" KARGS=hvc0
-    VMLINUX=vmlinux
-    KCONF=PPC64,PPC_PSERIES,PPC_OF_BOOT_TRAMPOLINE,BLK_DEV_SD,SCSI_LOWLEVEL,SCSI_IBMVSCSI,ATA,NET_VENDOR_IBM,IBMVETH,HVC_CONSOLE,PPC_TRANSACTIONAL_MEM,PPC_DISABLE_WERROR,SECTION_MISMATCH_WARN_ONLY
-    [ "$TARGET" == powerpc64le ] && KCONF=$KCONF,CPU_LITTLE_ENDIAN
-  elif [ "$TARGET" = s390x ]; then
-    QEMU="s390x" KARCH=s390 VMLINUX=arch/s390/boot/bzImage
-    KCONF=MARCH_Z900,PACK_STACK,NET_CORE,VIRTIO_NET,VIRTIO_BLK,SCLP_TTY,SCLP_CONSOLE,SCLP_VT220_TTY,SCLP_VT220_CONSOLE,S390_GUEST
-  elif [ "$TARGET" == sh2eb ]; then
-    BUILTIN=1 KARCH=sh VMLINUX=vmlinux
-    KERNEL_CONFIG=$'CONFIG_MEMORY_START=0x10000000\nCONFIG_CMDLINE="console=ttyUL0 earlycon"'
-    KCONF=CPU_SUBTYPE_J2,CPU_BIG_ENDIAN,SH_JCORE_SOC,SMP,BINFMT_ELF_FDPIC,JCORE_EMAC,SERIAL_UARTLITE,SERIAL_UARTLITE_CONSOLE,HZ_100,CMDLINE_OVERWRITE,SPI,SPI_JCORE,MMC,PWRSEQ_SIMPLE,MMC_BLOCK,MMC_SPI
-  elif [ "$TARGET" == sh4 ]; then
-    QEMU="sh4 -M r2d -serial null -serial mon:stdio" KARCH=sh
-    KARGS="ttySC1 noiotrap" VMLINUX=arch/sh/boot/zImage
-    KERNEL_CONFIG="CONFIG_MEMORY_START=0x0c000000"
-    KCONF=CPU_SUBTYPE_SH7751R,MMU,VSYSCALL,SH_FPU,SH_RTS7751R2D,RTS7751R2D_PLUS,SERIAL_SH_SCI,SERIAL_SH_SCI_CONSOLE,PCI,NET_VENDOR_REALTEK,8139CP,PCI,BLK_DEV_SD,ATA,ATA_SFF,ATA_BMDMA,PATA_PLATFORM,BINFMT_ELF_FDPIC,BINFMT_FLAT
-#see also SPI SPI_SH_SCI MFD_SM501 RTC_CLASS RTC_DRV_R9701 RTC_DRV_SH RTC_HCTOSYS
-  else die "Unknown \$TARGET $TARGET"
-  fi
-
-  # Write the qemu launch script
-  if [ -n "$QEMU" ]; then
-    [ -z "$BUILTIN" ] && INITRD="-initrd initramfs.cpio.gz"
-    { echo qemu-system-"$QEMU" '"$@"' $QEMU_MORE -nographic -no-reboot -m 256 \
-        -kernel linux-kernel $INITRD ${DTB:+-dtb linux.dtb} \
-        "-append \"panic=1 HOST=$TARGET console=$KARGS \$KARGS\"" &&
-      echo "echo -e '\\e[?7h'"
-    } > "$OUTPUT"/run-qemu.sh &&
-    chmod +x "$OUTPUT"/run-qemu.sh || exit 1
-  fi
-
-  announce "linux-$KARCH"
-  pushd "$LINUX" && make distclean && popd &&
-  cp -sfR "$LINUX" "$TEMP/linux" && pushd "$TEMP/linux" &&
-
-  # Write linux-miniconfig
-  { echo "# make ARCH=$KARCH allnoconfig KCONFIG_ALLCONFIG=linux-miniconfig"
-    echo -e "# make ARCH=$KARCH -j \$(nproc)\n# boot $VMLINUX\n\n"
-
-    # Expand list of =y symbols, first generic then architecture-specific
-    for i in BINFMT_ELF,BINFMT_SCRIPT,NO_HZ,HIGH_RES_TIMERS,BLK_DEV,BLK_DEV_INITRD,RD_GZIP,BLK_DEV_LOOP,EXT4_FS,EXT4_USE_FOR_EXT2,VFAT_FS,FAT_DEFAULT_UTF8,MISC_FILESYSTEMS,SQUASHFS,SQUASHFS_XATTR,SQUASHFS_ZLIB,DEVTMPFS,DEVTMPFS_MOUNT,TMPFS,TMPFS_POSIX_ACL,NET,PACKET,UNIX,INET,IPV6,NETDEVICES,NET_CORE,NETCONSOLE,ETHERNET,COMPAT_32BIT_TIME,EARLY_PRINTK,IKCONFIG,IKCONFIG_PROC $KCONF $KEXTRA ; do
-      echo "# architecture ${X:-independent}"
-      csv2cfg "$i" y
-      X=specific
-    done
-    [ -n "$BUILTIN" ] && echo -e CONFIG_INITRAMFS_SOURCE="\"$OUTPUT/fs\""
-    for i in $MODULES; do csv2cfg "$i" m; done
-    echo "$KERNEL_CONFIG"
-  } > "$OUTPUT/linux-miniconfig" &&
-  make ARCH=$KARCH allnoconfig KCONFIG_ALLCONFIG="$OUTPUT/linux-miniconfig" &&
-
-  # Second config pass to remove stupid kernel defaults
-  # See http://lkml.iu.edu/hypermail/linux/kernel/1912.3/03493.html
-  sed -e 's/# CONFIG_EXPERT .*/CONFIG_EXPERT=y/' -e "$(sed -E -e '/^$/d' \
-    -e 's@([^,]*)($|,)@/^CONFIG_\1=y/d;$a# CONFIG_\1 is not set\n@g' \
-       <<< VT,SCHED_DEBUG,DEBUG_MISC,X86_DEBUG_FPU)" -i .config &&
-  yes "" | make ARCH=$KARCH oldconfig > /dev/null &&
-  cp .config "$OUTPUT/linux-fullconfig" &&
-
-  # Build kernel. Copy config, device tree binary, and kernel binary to output
-  make ARCH=$KARCH CROSS_COMPILE="$CROSS_COMPILE" -j $(nproc) all || exit 1
-  [ -n "$DTB" ] && { cp "$DTB" "$OUTPUT/linux.dtb" || exit 1 ;}
-  if [ -n "$MODULES" ]; then
-    make ARCH=$KARCH INSTALL_MOD_PATH=modz modules_install &&
-      (cd modz && find lib/modules | cpio -o -H newc $CPIO_OPTS ) | gzip \
-       > "$OUTPUT/modules.cpio.gz" || exit 1
-  fi
-  cp "$VMLINUX" "$OUTPUT"/linux-kernel && cd .. && rm -rf linux && popd ||exit 1
-fi
-
-# clean up and package root filesystem for initramfs.
-if [ -z "$BUILTIN" ]; then
-  announce initramfs
-  { (cd "$ROOT" && find . | cpio -o -H newc $CPIO_OPTS ) || exit 1
-    ! test -e "$OUTPUT/modules.cpio.gz" || zcat $_;} | gzip \
-    > "$OUTPUT"/initramfs.cpio.gz || exit 1
-fi
-
-mv "$LOG/$CROSS".{n,y}
-rmdir "$TEMP" "$BUILD" 2>/dev/null || exit 0 # remove if empty, not an error
+#!/usr/bin/printf Moved to mkroot/mkroot.sh\n\c%s
diff --git a/scripts/root/overlay b/scripts/root/overlay
deleted file mode 100755
index f02f3db0..00000000
--- a/scripts/root/overlay
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/echo Try "scripts/mkroot.sh overlay"
-
-cp -a "${OVERLAY:=overlay}"/. "$ROOT"/.
diff --git a/toys/posix/tar.c b/toys/posix/tar.c
index 5af32db8..ea8edbf7 100644
--- a/toys/posix/tar.c
+++ b/toys/posix/tar.c
@@ -1147,7 +1147,7 @@ void tar_main(void)
     if (FLAG(j)||FLAG(z)||FLAG(I)||FLAG(J)) {
       int pipefd[2] = {-1, TT.fd};
 
-      xpopen_both((char *[]){get_archiver(), 0}, pipefd);
+      TT.pid = xpopen_both((char *[]){get_archiver(), 0}, pipefd);
       close(TT.fd);
       TT.fd = pipefd[0];
     }
@@ -1159,6 +1159,7 @@ void tar_main(void)
     } while (TT.incl != (dl = dl->next));
 
     writeall(TT.fd, toybuf, 1024);
+    close(TT.fd);
   }
   if (TT.pid) {
     TT.pid = xpclose_both(TT.pid, 0);
diff --git a/toys/posix/test.c b/toys/posix/test.c
index f9a2bbbb..cdb13e2a 100644
--- a/toys/posix/test.c
+++ b/toys/posix/test.c
@@ -28,7 +28,7 @@ config TEST
     STRING is:
       -n  nonzero size   -z  zero size
     FD (integer file descriptor) is:
-      -t  a TTY
+      -t  a TTY          -T  open
 
     --- Tests with one argument on each side of an operator:
     Two strings:
@@ -109,6 +109,7 @@ static int do_test(char **args, int *count)
     } else if (c == 'z') return !*args[1];
     else if (c == 'n') return *args[1];
     else if (c == 't') return isatty(atolx(args[1]));
+    else if (c == 'T') return -1 != fcntl(atolx(args[1]), F_GETFL);
   }
   return *count = 0;
 }
diff --git a/www/faq.html b/www/faq.html
index 79200550..d166bad5 100755
--- a/www/faq.html
+++ b/www/faq.html
@@ -759,7 +759,7 @@ auditable version of the cmdline portion of that base.</p>
 
 <hr /><h2><a name="mkroot" />Q: How do you build a working Linux system with toybox?</h2>
 
-<p>A: Toybox has a built-in <a href=https://github.com/landley/toybox/blob/master/scripts/mkroot.sh>system builder</a>, with the Makefile target "<b>make
+<p>A: Toybox has a built-in <a href=https://github.com/landley/toybox/blob/master/mkroot/mkroot.sh>system builder</a> called "<a href=https://github.com/landley/toybox/blob/master/mkroot/README>mkroot</a>", with the Makefile target "<b>make
 root</b>". To enter the resulting root filesystem, "<b>sudo chroot
 root/host/fs /init</b>". Type "exit" to get back out.</p>
 
@@ -832,7 +832,7 @@ to the build, by calling the script directly and listing packages on
 the command line:</p>
 
 <blockquote>
-<p><b>scripts/mkroot.sh CROSS=all LINUX=~/linux dropbear</b></p>
+<p><b>mkroot/mkroot.sh CROSS=all LINUX=~/linux dropbear</b></p>
 </blockquote>
 
 <p>An example package build script (building the dropbear ssh server, adding a