The 'userland_*' flags have proven not good enough to determine the availability of lock helpers. Fabian provided a nice portable locking code instead.
Fixes: https://bugs.gentoo.org/show_bug.cgi?id=466554 --- gx86/eclass/multibuild.eclass | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/gx86/eclass/multibuild.eclass b/gx86/eclass/multibuild.eclass index acfdbbd..819c814 100644 --- a/gx86/eclass/multibuild.eclass +++ b/gx86/eclass/multibuild.eclass @@ -251,38 +251,39 @@ multibuild_merge_root() { local src=${1} local dest=${2} - local lockfile=${T}/multibuild_merge_lock + local lockfile=${T}/.multibuild_merge_lock + local lockfile_l=${lockfile}.${$} local ret + # Lock the install tree for merge. The touch+ln method ensures race + # condition-free locking with maximum portability. + touch "${lockfile_l}" || die + until ln "${lockfile_l}" "${lockfile}" &>/dev/null; do + sleep 1 + done + rm "${lockfile_l}" || die + if use userland_BSD; then - # Locking is done by 'lockf' which can wrap a command. # 'cp -a -n' is broken: # http://www.freebsd.org/cgi/query-pr.cgi?pr=174489 # using tar instead which is universal but terribly slow. tar -C "${src}" -f - -c . \ - | lockf "${lockfile}" tar -x -f - -C "${dest}" + | tar -x -f - -C "${dest}" [[ ${PIPESTATUS[*]} == '0 0' ]] ret=${?} elif use userland_GNU; then - # GNU has 'flock' which can't wrap commands but can lock - # a fd which is good enough for us. - # and cp works with '-a -n'. - - local lock_fd - redirect_alloc_fd lock_fd "${lockfile}" '>>' - flock ${lock_fd} + # cp works with '-a -n'. cp -a -l -n "${src}"/. "${dest}"/ ret=${?} - - # Close the lock file when we are done with it. - # Prevents deadlock if we aren't in a subshell. - eval "exec ${lock_fd}>&-" else die "Unsupported userland (${USERLAND}), please report." fi + # Remove the lock. + rm "${lockfile}" || die + if [[ ${ret} -ne 0 ]]; then die "${MULTIBUILD_VARIANT:-(unknown)}: merging image failed." fi -- 1.8.2.1
