Commit d3d888c9 authored by Simon McVittie's avatar Simon McVittie

capture-libs: Treat unversioned libraries as in indeterminate order

On at least Debian, Ubuntu and Manjaro, libgcc_s.so.1 is a regular
file, not a symlink to a versioned name (libgcc_s.so.1.2.3) like most
shared libraries.

However, on Fedora 30 it is a symlink to a versioned name like
libgcc_s-9-20190827.so.1. The name used in Fedora happens to be less
than libgcc_s.so.1 in strverscmp() order, causing capsule-capture-libs
to prefer the Debian/Manjaro libgcc_s.so.1, even if the container is
older. This can cause problems if an old Debian-derived container like the
Steam Runtime is used on a newer Fedora host, with host graphics drivers
imported by using capsule-capture-libs: the container's libgcc_s.so.1
does not satisfy the versioned symbol requirements of the graphics driver,
causing loading to fail.

Treat a regular file libgcc_s.so.1 as indeterminate order (or "equal"),
so that we fall back to the default behaviour, which is currently to
take the host version of the library in the case of a tie.

This is a stopgap solution: ideally we would consider the versioned
symbols exported by both libraries, and take whichever one has a superset
of the version definitions exported by the other, if there is a strict
superset in either direction (in the case of libgcc, in fact there is).
Signed-off-by: Simon McVittie's avatarSimon McVittie <smcv@collabora.com>
parent 702fc558
......@@ -356,6 +356,41 @@ library_cmp_by_name( const char *soname,
"\"%s\" from \"%s\"",
soname, left_basename, left_from, right_basename, right_from );
if( strcmp( left_basename, right_basename ) == 0 )
{
DEBUG( DEBUG_TOOL,
"Name of %s \"%s\" from \"%s\" compares the same as "
"\"%s\" from \"%s\"",
soname, left_basename, left_from, right_basename, right_from );
return 0;
}
if( strcmp( soname, left_basename ) == 0 )
{
/* In some distributions (Debian, Ubuntu, Manjaro)
* libgcc_s.so.1 is a plain file, not a symlink to a
* version-suffixed version. We cannot know just from the name
* whether that's older or newer, so assume equal. The caller is
* responsible for figuring out which one to prefer. */
DEBUG( DEBUG_TOOL,
"Unversioned %s \"%s\" from \"%s\" cannot be compared with "
"\"%s\" from \"%s\"",
soname, left_basename, left_from,
right_basename, right_from );
return 0;
}
if( strcmp( soname, right_basename ) == 0 )
{
/* The same, but the other way round */
DEBUG( DEBUG_TOOL,
"%s \"%s\" from \"%s\" cannot be compared with "
"unversioned \"%s\" from \"%s\"",
soname, left_basename, left_from,
right_basename, right_from );
return 0;
}
return ( strverscmp( left_basename, right_basename ) );
}
......@@ -489,6 +524,12 @@ capture_one( const char *soname, capture_flags flags,
{
const char *needed_path_in_container = container.needed[0].path;
/* TODO: Ideally we would actually dlopen the libraries and
* inspect their symbol tables, either in ambiguous cases
* or always - but that's easier said than done, because
* private symbols exist. For now we just use
* library_cmp_by_name(). */
/* If equal, we prefer the provider over the container */
if( library_cmp_by_name( needed_name,
needed_path_in_container,
......
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