From 4dd4c54ccb1e41e37ef7708376ae1f2ca28712cf Mon Sep 17 00:00:00 2001
From: David James <davidjames@chromium.org>
Date: Wed, 10 Aug 2011 10:19:47 -0700
Subject: [PATCH] Fix race condition by using different symlinks for factory
 images.

Both the tests and archive_build read and write the latest symlink.
This CL fixes a race condition in archive_build by moving away from
using the latest symlink in archive_build.

BUG=chromium-os:18967
TEST=Run release cbuildbot archive_build on x86-mario-release.
     Verify it completes successfully and that latest symlink
     is unchanged now.

Change-Id: Ia32d20903f3ef74e360944fbabdd9834c0edb99a
Reviewed-on: http://gerrit.chromium.org/gerrit/5746
Reviewed-by: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
---
 archive_build.sh | 42 +++++++++++-------------------------------
 build_image      |  9 ++++++---
 make_netboot.sh  | 12 +++++++++---
 3 files changed, 26 insertions(+), 37 deletions(-)

diff --git a/archive_build.sh b/archive_build.sh
index 9e1b0bec82..77b7be8199 100755
--- a/archive_build.sh
+++ b/archive_build.sh
@@ -154,10 +154,12 @@ echo "archive to file: $ZIPFILE"
 mkdir -p "$OUTDIR"
 
 # Modify image for test if flag set.
+CHROOT_IMAGE_DIR=$(reinterpret_path_for_chroot "$FLAGS_from")
 if [ $FLAGS_test_mod -eq $FLAGS_TRUE ]; then
   echo "Modifying image for test"
   ./enter_chroot.sh $CHROOT_ENV -- ./mod_image_for_test.sh \
-    --board $FLAGS_board --noinplace --yes
+    --board $FLAGS_board --noinplace --yes \
+    --image $CHROOT_IMAGE_DIR/$CHROMEOS_IMAGE_NAME
 
   pushd "${FLAGS_chroot}/build/${FLAGS_board}/usr/local"
   echo "Archiving autotest build artifacts"
@@ -172,8 +174,6 @@ fi
 
 # Modify for recovery
 if [ $FLAGS_official_build -eq $FLAGS_TRUE ]; then
-  BUILDVER="$(readlink ${IMAGES_DIR}/${FLAGS_board}/latest)"
-  CHROOT_IMAGE_DIR=/home/$USER/trunk/src/build/images/$FLAGS_board/$BUILDVER
   ./enter_chroot.sh $CHROOT_ENV -- ./mod_image_for_recovery.sh \
     --board $FLAGS_board --image $CHROOT_IMAGE_DIR/chromiumos_base_image.bin
 fi
@@ -194,17 +194,8 @@ if [ $FLAGS_factory_test_mod -eq $FLAGS_TRUE ]; then
   # fail. You must explictly call replace and specify a unique name numerically
   # using build_attempt.
   ./enter_chroot.sh $CHROOT_ENV -- ./build_image --board $FLAGS_board \
-      --replace --noenable_rootfs_verification --build_attempt 4
-
-  ./enter_chroot.sh $CHROOT_ENV -- ./mod_image_for_test.sh \
-      --board $FLAGS_board --yes --noinplace --factory
-
-  # Get the factory test dir: It is the newest build.
-  # This is the output dir for the factory shim, the factory test and
-  # release images will remain in IMG_DIR, defined previously.
-  FACTORY_DIR="$(readlink ${IMAGES_DIR}/${FLAGS_board}/latest)"
-
-  echo "Factory image dir: ${FACTORY_DIR}"
+      --replace --noenable_rootfs_verification --build_attempt 4 \
+      --symlink factory_test --factory --test
 fi
 
 # Build differently sized shims. Currently only factory install shim is
@@ -220,22 +211,20 @@ if [ $FLAGS_factory_install_mod -eq $FLAGS_TRUE ]; then
   # fail. You must explictly call replace and specify a unique name numerically
   # using build_attempt.
   ./enter_chroot.sh $CHROOT_ENV -- ./build_image --board $FLAGS_board \
-    --factory_install --replace --build_attempt 7
+    --factory_install --replace --build_attempt 7 --symlink factory_shim
 
-  # Get the install shim dir: It is the newest build.
-  # This is the output dir for the factory shim, the factory test and
-  # release images will remain in IMG_DIR, defined previously.
-  SHIM_DIR="$(readlink ${IMAGES_DIR}/${FLAGS_board}/latest)"
+  # Get the install shim dir: It is the newest factory_shim build.
+  SHIM_DIR="${IMAGES_DIR}/${FLAGS_board}/factory_shim"
+  CHROOT_SHIM_DIR=$(reinterpret_path_for_chroot "${SHIM_DIR}")
 
   # For ARM we should creat a netboot image.
   # Only ARM has "uimg" uboot format kernels.
   # TODO(anush): We should have build infrastructure that can directly
   # query architecture.
   if [ -f "${SYSROOT}/boot/vmlinux.uimg" ]; then
-    ./enter_chroot.sh $CHROOT_ENV -- ./make_netboot.sh --board $FLAGS_board
+    ./enter_chroot.sh $CHROOT_ENV -- ./make_netboot.sh --board $FLAGS_board \
+        --image "$CHROOT_SHIM_DIR/factory_install_shim.bin"
   fi
-
-  echo "Factory install shim dir: ${SHIM_DIR}"
 fi
 
 # Zip the build
@@ -251,16 +240,7 @@ if [ $FLAGS_factory_test_mod -eq $FLAGS_TRUE ] || \
   # signing and packaging utilities need unpack_partitions.sh.
   echo "Compressing factory software"
   pushd ..
-  [ -n "${SHIM_DIR}" ] && rm -f factory_shim && \
-      ln -s "${SHIM_DIR}" factory_shim
-  [ -n "${FACTORY_DIR}" ] && rm -f factory_test && \
-      ln -s "${FACTORY_DIR}" factory_test
 
-  # Restore "latest" status to the original image.
-  # The "latest" symlink and latest timestamp are used extensively
-  # throughout the build scripts rather than explicitly specifying an image.
-  touch "${IMG_DIR}"
-  [ -n "${IMG_DIR}" ] && rm -f latest && ln -s "${IMG_DIR}" latest
   FACTORY_MANIFEST=$(find factory_shim factory_test -follow -type f  |
       grep -E "(factory_image|factory_install|partition|netboot|hwid)")
   rm -f "${FACTORY_ZIPFILE}"
diff --git a/build_image b/build_image
index 710a4fce08..5305f1434c 100755
--- a/build_image
+++ b/build_image
@@ -68,6 +68,8 @@ DEFINE_string verity_algorithm "sha1" \
   "Cryptographic hash algorithm used for kernel vboot. Default : sha1"
 DEFINE_boolean standard_backdoor ${FLAGS_TRUE} \
   "Install standard backdoor credentials for testing"
+DEFINE_string symlink "latest" \
+  "Symlink name to use for this image."
 
 # TODO(clchiou): Remove this flag after buildbot is fixed
 DEFINE_boolean crosbug12352_arm_kernel_signing ${FLAGS_TRUE} \
@@ -811,9 +813,10 @@ rmdir "${ROOT_FS_DIR}" "${STATEFUL_FS_DIR}" "${ESP_FS_DIR}"
 
 # Generating AU generator zip file to run outside chroot
 generate_au_zip || echo "Failed generating AU zip file - ignoring Error..."
-# Create a 'latest' link
-rm -f ${FLAGS_output_root}/${BOARD}/latest
-ln -s $(basename ${OUTPUT_DIR}) ${FLAGS_output_root}/${BOARD}/latest
+
+# Create a named symlink.
+LINK_NAME="${FLAGS_output_root}/${BOARD}/${FLAGS_symlink}"
+ln -sfT $(basename ${OUTPUT_DIR}) ${LINK_NAME}
 
 echo "Done.  Image created in ${OUTPUT_DIR}"
 echo "Chromium OS image created as ${PRISTINE_IMAGE_NAME}"
diff --git a/make_netboot.sh b/make_netboot.sh
index d795c42887..2d1eb1ac4b 100755
--- a/make_netboot.sh
+++ b/make_netboot.sh
@@ -42,6 +42,7 @@ get_default_board
 
 DEFINE_string board "${DEFAULT_BOARD}" \
   "The board to build an image for."
+DEFINE_string image "" "Path to the image to use"
 
 # Parse command line.
 FLAGS "$@" || exit 1
@@ -52,10 +53,15 @@ set -e
 SYSROOT="${GCLIENT_ROOT}/chroot/build/${FLAGS_board}"
 # build_image artifact output.
 IMAGES_DIR="${CHROOT_TRUNK_DIR}/src/build/images"
-# Canonical install shim name.
-INSTALL_SHIM="factory_install_shim.bin"
 
-cd ${IMAGES_DIR}/${FLAGS_board}/latest
+if [ -n "${FLAGS_image}" ]; then
+  cd $(dirname "${FLAGS_image}")
+  INSTALL_SHIM=$(basename "${FLAGS_image}")
+else
+  cd ${IMAGES_DIR}/${FLAGS_board}/latest
+  # Canonical install shim name.
+  INSTALL_SHIM="factory_install_shim.bin"
+fi
 
 if [ ! -f "${INSTALL_SHIM}" ]; then
   echo "Cannot locate ${INSTALL_SHIM}, nothing to netbootify!"