From e98c029717016dfa3e5c618c9fc46da9b2142dcc Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Mon, 23 Jul 2012 18:42:18 -0400 Subject: [PATCH] Handle platforms that don't support linking to a symlink E.g. Darwin doesn't allow this. --- configure.ac | 12 ++++++++++++ src/libstore/optimise-store.cc | 9 +++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index a2512cfe9..f920b8c10 100644 --- a/configure.ac +++ b/configure.ac @@ -120,6 +120,18 @@ AC_CHECK_HEADERS([sys/mount.h], [], [], AC_CHECK_FUNCS([lutimes]) +# Check whether the store optimiser can optimise symlinks. +AC_MSG_CHECKING([whether it is possible to create a link to a symlink]) +ln -s bla tmp_link +if ln tmp_link tmp_link2 2> /dev/null; then + AC_MSG_RESULT(yes) + AC_DEFINE(CAN_LINK_SYMLINK, 1, [Whether link() works on symlinks.]) +else + AC_MSG_RESULT(no) +fi +rm -f tmp_link tmp_link2 + + # Check for . AC_LANG_PUSH(C++) AC_CHECK_HEADERS([locale]) diff --git a/src/libstore/optimise-store.cc b/src/libstore/optimise-store.cc index e5bfa332d..486538bd2 100644 --- a/src/libstore/optimise-store.cc +++ b/src/libstore/optimise-store.cc @@ -62,8 +62,13 @@ void LocalStore::optimisePath_(OptimiseStats & stats, const Path & path) return; } - /* We can hard link regular files and symlinks. */ - if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) return; + /* We can hard link regular files and maybe symlinks. */ + if (!S_ISREG(st.st_mode) +#if CAN_LINK_SYMLINK + x + && !S_ISLNK(st.st_mode) +#endif + ) return; /* Sometimes SNAFUs can cause files in the Nix store to be modified, in particular when running programs as root under