11:51 a.m.
The libc.so library requires certainly functionality to be
provided by the ld-linux.so library. The ld-linux.so is loaded
by the kernel based on the PT_INTERP ELF section, and as such
LD_LIBRARY_PATH has no effect.
So, although libvirt-sandbox-init-{qemu,lxc} set LD_LIBRARY_PATH
to force use of the libs from the host OS image, the common
init program was stil using the ld-linux.so from the guest OS
image. Sometimes this works, sometimes it breaks.
When trying to run Fedora 19 as the root filesystem from a
Fedora 22 host, it would break thus:
/etc/libvirt-sandbox/scratch/.libs/libvirt-sandbox-init-common: relocation error:
/etc/libvirt-sandbox/scratch/.libs/libc.so.6: symbol _dl_find_dso_for_object, version
GLIBC_PRIVATE not defined in file ld-linux-x86-64.so.2 with link time reference
To deal with this we must ensure that we always invoke the
libvirt-sandbox-init-common program using the ld-linux that
was provided by the host OS image.
The sandbox builder is tweaked so that it always copies the
host ld-linux.so into the libs scratch directory, and gives
it a predictable name 'ld.so', since every architecture seems
to have a different name.
The libvirt-sandbox-init-{lxc,qemu} files are changed so that
instead of exec'ing libvirt-sandbox-init-common directly, they
will load it via the ld.so file.
---
libvirt-sandbox/libvirt-sandbox-builder.c | 28 +++++++++++++++++++++++-----
libvirt-sandbox/libvirt-sandbox-init-lxc.c | 1 +
libvirt-sandbox/libvirt-sandbox-init-qemu.c | 1 +
3 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/libvirt-sandbox/libvirt-sandbox-builder.c
b/libvirt-sandbox/libvirt-sandbox-builder.c
index 2726868..e615606 100644
--- a/libvirt-sandbox/libvirt-sandbox-builder.c
+++ b/libvirt-sandbox/libvirt-sandbox-builder.c
@@ -252,10 +252,11 @@ GVirConnection
*gvir_sandbox_builder_get_connection(GVirSandboxBuilder *builder)
static gboolean gvir_sandbox_builder_copy_file(const char *path,
const char *libsdir,
+ const char *newname,
GError **error)
{
gchar *name = g_path_get_basename(path);
- gchar *target = g_build_filename(libsdir, name, NULL);
+ gchar *target = g_build_filename(libsdir, newname ? newname : name, NULL);
GFile *srcFile = g_file_new_for_path(path);
GFile *tgtFile = g_file_new_for_path(target);
gboolean result = FALSE;
@@ -285,7 +286,7 @@ static gboolean gvir_sandbox_builder_copy_program(const char
*program,
const gchar *argv[] = {LDD_PATH, program, NULL};
gboolean result = FALSE;
- if (!gvir_sandbox_builder_copy_file(program, dest, error))
+ if (!gvir_sandbox_builder_copy_file(program, dest, NULL, error))
goto cleanup;
@@ -301,14 +302,31 @@ static gboolean gvir_sandbox_builder_copy_program(const char
*program,
*tmp = '\0';
/* Search the line for the library path */
- start = strstr(line, " => ");
+ start = strstr(line, "/");
end = strstr(line, " (");
if (start && end) {
- start = start + 4;
+ const gchar *newname = NULL;
*end = '\0';
- if (!gvir_sandbox_builder_copy_file(start, dest, error))
+ /* There are countless different naming schemes for
+ * the ld-linux.so library across architectures. Pretty
+ * much the only thing in common is they start with
+ * the two letters 'ld'. The LDD program prints it
+ * out differently too - it doesn't include " => "
+ * as this library is special - its actually a static
+ * linked executable not a library.
+ *
+ * To make life easier for libvirt-sandbox-init-{qemu,lxc}
+ * we just call the file 'ld.so' when we copy it into our
+ * scratch dir, no matter what it was called on the host.
+ */
+ if (!strstr(line, " => ") &&
+ strstr(start, "/ld")) {
+ newname = "ld.so";
+ }
+
+ if (!gvir_sandbox_builder_copy_file(start, dest, newname, error))
goto cleanup;
}
diff --git a/libvirt-sandbox/libvirt-sandbox-init-lxc.c
b/libvirt-sandbox/libvirt-sandbox-init-lxc.c
index e2fe7f0..d1e4a79 100644
--- a/libvirt-sandbox/libvirt-sandbox-init-lxc.c
+++ b/libvirt-sandbox/libvirt-sandbox-init-lxc.c
@@ -77,6 +77,7 @@ main(int argc, char **argv)
args[narg++] = "1000";
}
+ args[narg++] = SANDBOXCONFIGDIR "/.libs/ld.so";
args[narg++] = SANDBOXCONFIGDIR "/.libs/libvirt-sandbox-init-common";
if (debug)
args[narg++] = "-d";
diff --git a/libvirt-sandbox/libvirt-sandbox-init-qemu.c
b/libvirt-sandbox/libvirt-sandbox-init-qemu.c
index 09580da..cd6055a 100644
--- a/libvirt-sandbox/libvirt-sandbox-init-qemu.c
+++ b/libvirt-sandbox/libvirt-sandbox-init-qemu.c
@@ -422,6 +422,7 @@ main(int argc ATTR_UNUSED, char **argv ATTR_UNUSED)
args[narg++] = "1000";
}
+ args[narg++] = SANDBOXCONFIGDIR "/.libs/ld.so";
args[narg++] = SANDBOXCONFIGDIR "/.libs/libvirt-sandbox-init-common";
if (debug)
args[narg++] = "-d";
--
2.4.3