• Simon McVittie's avatar
    build: Add a symbol version to all exported symbols · aa69d180
    Simon McVittie authored
    The --default-symver linker option attaches a default version definition
    (the SONAME) to every exported symbol. It is supported since at least
    GNU binutils 2.22 in 2011 (older versions not tested).
    
    With this version definition, newly-linked binaries that depend on the
    json-glib shared library will refer to its symbols in a versioned form,
    preventing their references from being resolved to a symbol of the same
    name exported by json-c or libjansson if those libraries appear in
    dependency search order before json-glib, which will usually result in
    a crash. This is necessary because ELF symbol resolution normally uses
    a single flat namespace, not a tree like Windows symbol resolution.
    At least one symbol (json_object_iter_next()) is exported by all three
    JSON libraries.
    
    Linking with -Bsymbolic is not enough to have this effect in all cases,
    because -Bsymbolic only affects symbol lookup within a shared object,
    for example when json_from_string() calls json_parser_new(). It does
    not affect symbol lookup when external code calls into json-glib,
    for example when libedataserver calls json_parser_new().
    
    This change will also not prevent code that depends on json-c or
    libjansson from finding json-glib's symbols and crashing; to prevent
    that, a corresponding change in json-c or libjansson would be needed.
    
    Adding a symbol-version is a backwards-compatible change, but once
    added, removing or changing the symbol-version would be an incompatible
    change that requires a SONAME bump.
    
    Partially resolves #33
    and glib#2147.
    Signed-off-by: Simon McVittie's avatarSimon McVittie <smcv@collabora.com>
    aa69d180
meson.build 4.95 KB