prepstrip: fix hardlink race in process_elf

diff --git a/bin/ebuild-helpers/prepstrip b/bin/ebuild-helpers/prepstrip
index 6f2c742cc8da2b9e7e7e96f3f50779a56ce74409..deb5cabc5fc98a2f9aa7d7f45209dc47dab4ecdf 100755 (executable)
--- a/bin/ebuild-helpers/prepstrip
+++ b/bin/ebuild-helpers/prepstrip
@@ -137,12 +137,7 @@ save_elf_debug() {
                local args="a-x,o-w"
                [[ -g ${x} || -u ${x} ]] && args+=",go-r"
                chmod ${args} "${y}"
-               if ! ln "${y}" "${inode}" ; then
-                       # This means a parallel process has already created the
-                       # inode link. So, replace ${y} with a link to that inode.
-                       rm -f "${y}"
-                       ln "${inode}" "${y}"
-               fi
+               ln "${y}" "${inode}"
        fi
 
        # if we don't already have build-id from debugedit, look it up
@@ -168,6 +163,20 @@ process_elf() {
        save_elf_sources "${x}"
 
        if ${strip_this} ; then
+
+               # If two processes try to strip the same hardlink at the same
+               # time, it will cause one of them to lose the splitdebug info.
+               # So, use a lockfile to prevent interference (easily observed
+               # with dev-vcs/git which creates ~109 hardlinks to one file in
+               # /usr/libexec/git-core).
+               local lockfile=$(inode_file_link "${x}")_lockfile
+               if ! ln "${x}" "${lockfile}" ; then
+                       while [[ -f ${lockfile} ]] ; do
+                               sleep 1
+                       done
+                       unset lockfile
+               fi
+
                # see if we can split & strip at the same time
                if [[ -n ${SPLIT_STRIP_FLAGS} ]] ; then
                        local shortname="${x##*/}.debug"
@@ -181,6 +190,7 @@ process_elf() {
                        save_elf_debug "${x}"
                        ${STRIP} ${strip_flags} "${x}"
                fi
+               [[ -n ${lockfile} ]] && rm -f "${lockfile}"
        fi
 }