Merge ~xnox/ubuntu/+source/initramfs-tools:libgcc_s into ubuntu/+source/initramfs-tools:ubuntu/devel

[Dimitri John Ledkov]

Reliable libgcc_s inclusion

[Steve Langasek (vorlon)]

Can you get agreement on this upstream in Debian first?

diff --git a/debian/changelog b/debian/changelog
index cfc177f..56c17a6 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,23 @@
+initramfs-tools (0.137ubuntu10) groovy; urgency=medium
+
+  * Properly fixup copying libgcc_s library into the initrd. LP: #1880853
+    Implemented differently from "[f2ac13e] hook-functions: copy_exec:
+    Copy libgcc_s.so.1 along with libpthread.so.* (Closes: #950254)". To
+    avoid circular shared library dependencies between compiler and libc,
+    libpthreads chooses to dlopen libgcc_s, instead of linking against
+    it. However, we have no way to parse/know what it needs. And even when
+    we hardcode to include libgcc_s1, we don't have a way to know which
+    libgcc_s1 is needed on a given system and from which path to include
+    it. But there is a hook-function to copy a binary and all of its
+    shared library dependencies. Thus create a stub empty executable, with
+    shared linking against pthreads and gcc_s1 and always include it in
+    the initrd. This way at initrd creation time, ldd is used to correctly
+    resolve these shared library dependencies and correctly copy them into
+    the initrd. This removes hardcoding paths as to where these libraries
+    must be copied from on the host.
+
+ -- Dimitri John Ledkov <[e-mail]>  Fri, 05 Jun 2020 13:38:11 +0100
+
 initramfs-tools (0.137ubuntu9) groovy; urgency=medium
 
   * Document add_mountroot_fail_hook correctly.
diff --git a/debian/initramfs-tools-bin.install b/debian/initramfs-tools-bin.install
index 9d63a93..bdc60f7 100644
--- a/debian/initramfs-tools-bin.install
+++ b/debian/initramfs-tools-bin.install
@@ -1,2 +1,3 @@
 src/wait-for-root	usr/lib/initramfs-tools/bin
 src/rzscontrol		usr/lib/initramfs-tools/bin
+src/gcc_s1-stub	usr/lib/initramfs-tools/bin
diff --git a/hook-functions b/hook-functions
index d80fe32..0517140 100644
--- a/hook-functions
+++ b/hook-functions
@@ -213,13 +213,6 @@ copy_exec() {
 			x="${nonoptlib}"
 		fi
 
-		# Handle common dlopen() dependency (Debian bug #950254)
-		case "${x}" in
-		*/libpthread.so.*)
-			copy_exec "${x%/*}/libgcc_s.so.1" || copy_exec "${x%/*}/../libgcc_s.so.1" || return
-			;;
-		esac
-
 		copy_file binary "${x}" || {
 			ret=$?
 			[ ${ret} = 1 ] || return $((ret - 1))
diff --git a/mkinitramfs b/mkinitramfs
index 637f1d6..2883a27 100644
--- a/mkinitramfs
+++ b/mkinitramfs
@@ -360,6 +360,9 @@ fi
 touch "${DESTDIR}/etc/fstab"
 ln -s /proc/mounts "${DESTDIR}/etc/mtab"
 
+# Install libc6, pthreads, and dlopened gcc_s.so.1 (Debian bug #950254)
+copy_exec /usr/lib/initrmafs-tools/bin/gcc_s1-stub /usr/lib/initrmafs-tools/bin/gcc_s1-stub
+
 # install wait-for-root binary.
 copy_exec /usr/lib/initramfs-tools/bin/wait-for-root /sbin
 
diff --git a/src/Makefile b/src/Makefile
index c7ac39e..6210775 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -8,7 +8,7 @@ LDFLAGS =
 
 
 .PHONY: all
-all: wait-for-root rzscontrol
+all: wait-for-root rzscontrol gcc_s1-stub
 
 wait-for-root: wait-for-root.o
 	$(CC) $(LDFLAGS) -o $@ $< $(UDEV_LIBS)
@@ -16,6 +16,9 @@ wait-for-root: wait-for-root.o
 rzscontrol: rzscontrol.o
 	$(CC) $(LDFLAGS) -o $@ $<
 
+gcc_s1-stub:
+	gcc -Wl,--no-as-needed -shared -pthread -l:libgcc_s.so.1 -o $@
+
 .PHONY: clean
 clean:
-	rm -f wait-for-root.o wait-for-root rzscontrol.o rzscontrol core *~
+	rm -f wait-for-root.o wait-for-root rzscontrol.o rzscontrol gcc_s1-stub core *~