commit: 44570a44be60a8fc33bd05089047c1f2980b3047
Author: Sergei Trofimovich <slyfox <AT> gentoo <DOT> org>
AuthorDate: Sat Sep 7 20:17:52 2019 +0000
Commit: Sergei Trofimovich <slyfox <AT> gentoo <DOT> org>
CommitDate: Sat Sep 7 21:29:12 2019 +0000
URL: https://gitweb.gentoo.org/proj/gcc-config.git/commit/?id=44570a44
gcc-config: store gcc backup into /lib/gcc-backup, not /lib
Writing (and removing) libraries to /lib outside package manager
was a surprise to users in bug #667020# where libunwind.so was
clobbered by gcc-config runs.
This change isolates all logic that handles file copies
outside package manager into /lib/gcc-backup directory.
To make new library still resolveable we install env.d entry
with contents of
LDPATH="/lib/gcc-backup"
Signed-off-by: Sergei Trofimovich <slyfox <AT> gentoo.org>
Makefile | 22 +++++++++++++++++++---
envd-gcc-backup | 3 +++
gcc-backup/README | 41 +++++++++++++++++++++++++++++++++++++++++
gcc-config | 17 ++++++++++++++++-
4 files changed, 79 insertions(+), 4 deletions(-)
diff --git a/Makefile b/Makefile
index 2b3b235..087000b 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,7 @@ EPREFIX ?=
PN = gcc-config
PV = git
P = $(PN)-$(PV)
+BACKUPDIR = gcc-backup
PREFIX = $(EPREFIX)/usr
BINDIR = $(PREFIX)/bin
@@ -11,15 +12,18 @@ ESELECTDIR = $(PREFIX)/share/eselect/modules
SUBLIBDIR = lib
LIBDIR = $(PREFIX)/$(SUBLIBDIR)
+LIBGCC_BACKUPDIR = $(EPREFIX)/$(SUBLIBDIR)/$(BACKUPDIR)
+
+ENVD = $(EPREFIX)/etc/env.d
MKDIR_P = mkdir -p -m 755
INSTALL_EXE = install -m 755
INSTALL_DATA = install -m 644
-all: .gcc-config
+all: .gcc-config .envd-gcc-backup
clean:
- rm -f .gcc-config
+ rm -f .gcc-config .envd-gcc-backup
.gcc-config: gcc-config
sed \
@@ -27,14 +31,26 @@ clean:
-e 's:@GENTOO_EPREFIX@:$(EPREFIX):g' \
-e 's:@GENTOO_LIBDIR@:$(SUBLIBDIR):g' \
-e 's:@PV@:$(PV):g' \
+ -e 's:@GENTOO_GCC_BACKUP_DIR@:$(BACKUPDIR):g' \
$< > $@
chmod a+rx $@
+.envd-gcc-backup: envd-gcc-backup
+ sed \
+ -e 's:@LIBGCC_BACKUPDIR@:$(LIBGCC_BACKUPDIR):g' \
+ $< > $@
+
install: all
- $(MKDIR_P) $(DESTDIR)$(BINDIR) $(DESTDIR)$(ESELECTDIR)
$(DESTDIR)$(DOCDIR)
+ $(MKDIR_P) $(DESTDIR)$(BINDIR)
$(INSTALL_EXE) .gcc-config $(DESTDIR)$(BINDIR)/gcc-config
+ $(MKDIR_P) $(DESTDIR)$(ESELECTDIR)
$(INSTALL_DATA) gcc.eselect $(DESTDIR)$(ESELECTDIR)
+ $(MKDIR_P) $(DESTDIR)$(DOCDIR)
$(INSTALL_DATA) README $(DESTDIR)$(DOCDIR)
+ $(MKDIR_P) $(DESTDIR)$(LIBGCC_BACKUPDIR)
+ $(INSTALL_DATA) gcc-backup/README $(DESTDIR)$(LIBGCC_BACKUPDIR)
+ $(MKDIR_P) $(DESTDIR)$(ENVD)
+ $(INSTALL_DATA) .envd-gcc-backup $(DESTDIR)$(ENVD)/99gcc-backup
test check: .gcc-config
cd tests && ./run_tests
diff --git a/envd-gcc-backup b/envd-gcc-backup
new file mode 100644
index 0000000..4367b62
--- /dev/null
+++ b/envd-gcc-backup
@@ -0,0 +1,3 @@
+# A fallback for libgcc_s.so.* and dependencies.
+# See @LIBGCC_BACKUPDIR@/README for details
+LDPATH="@LIBGCC_BACKUPDIR@"
diff --git a/gcc-backup/README b/gcc-backup/README
new file mode 100644
index 0000000..fdac223
--- /dev/null
+++ b/gcc-backup/README
@@ -0,0 +1,41 @@
+What is gcc-backup
+==================
+
+gcc-backup is a directory to backup critical runtime
+libraries used by gcc to link in code too big to inline it
+from code generator.
+
+See gcc/doc/libgcc.texi doc in gcc source tree.
+
+gcc-config is responsible to back up libgcc_s.so.* and it's
+runtime dependencies.
+
+Which systems needed this backup
+================================
+
+During normal system operation these libraries should not be
+needed (unless gcc installation is somehow completely broken).
+
+The main use case for libgcc-backup is booting of a system
+with the following properties:
+- '/usr' mount is separate from '/' mount
+- AND binaries in /bin (say, /bin/bash) are executed before
+ /usr is mounted
+
+Which systems link libgcc_s.so in
+=================================
+
+By default gcc attempts to link libgcc_s.so in into every
+binary and shared library. If code generator happens to
+generate the code that does not refer libgcc_s.so then
+-Wl,--as-needed linker option omits the dependency.
+
+Thus any system might have libgcc_s.so linked into any binary
+or shared library.
+
+What goes into this directory
+=============================
+
+- libgcc_s.so.* itself: gcc driver attempts to link it in as-is
+- libunwind.so.*: ia64-*-linux only, a runtime dependency of
+ libgcc_so.so.*
diff --git a/gcc-config b/gcc-config
index 01e2b90..65b30bc 100755
--- a/gcc-config
+++ b/gcc-config
@@ -42,6 +42,9 @@ PV="@PV@"
GENTOO_LIBDIR="@GENTOO_LIBDIR@"
[[ ${GENTOO_LIBDIR} == @*@ ]] && GENTOO_LIBDIR="lib"
+GENTOO_GCC_BACKUP_DIR="@GENTOO_GCC_BACKUP_DIR@"
+[[ ${GENTOO_GCC_BACKUP_DIR} == @*@ ]] && GENTOO_GCC_BACKUP_DIR="gcc-backup"
+
usage() {
cat <<-EOF
Usage: gcc-config [options] [CC Profile]
@@ -316,11 +319,23 @@ handle_split_usr() {
if is_same_mountpoint "${EROOT}/lib" "${ROOT}/${LDPATH}" ; then
local lib old_libs=0 saved_nullglob=$(shopt -p nullglob)
shopt -s nullglob
+
+ # We relied on these copies until Sept 2019.
+ # Can be removed in 2021.
for lib in "${EROOT}"/lib*/libgcc_s{.so*,*dylib}
"${EROOT}"/lib*/libunwind.so.7* ; do
# If we previously had stuff in /, make sure ldconfig
gets re-run.
rm -f "${lib}"
old_libs=1
done
+
+ for lib in \
+
"${EROOT}"/lib*/"${GENTOO_GCC_BACKUP_DIR}"/libgcc_s.so.* \
+
"${EROOT}"/lib*/"${GENTOO_GCC_BACKUP_DIR}"/libunwind.so.* ; do
+ # If we previously had stuff in /, make sure ldconfig
gets re-run.
+ rm -f "${lib}"
+ old_libs=1
+ done
+
${saved_nullglob}
return ${old_libs}
fi
@@ -328,7 +343,7 @@ handle_split_usr() {
# Only bother with this stuff for the native ABI. We assume the user
# doesn't have critical binaries for non-native ABIs which is fair.
local gcclib
- local libdir="${EROOT}${GENTOO_LIBDIR}"
+ local libdir="${EROOT}/${GENTOO_LIBDIR}/${GENTOO_GCC_BACKUP_DIR}"
mkdir -p "${libdir}"/.gcc.config.new || return 0 # !?!?!
for gcclib in gcc_s unwind ; do
# This assumes that we always have the .so symlink,
