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| author | Florian Weimer <fweimer@redhat.com> | 2022-08-24 17:35:36 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2022-08-24 17:35:57 +0200 |
| commit | 6f85dbf102ad7982409ba0fe96886caeb6389fef (patch) | |
| tree | 430440c34027af70ebf69884a6b4541d7055c3d2 /INSTALL | |
| parent | 06e4033c83276ed349d315bfbf651be56c3e2954 (diff) | |
| download | glibc-6f85dbf102ad7982409ba0fe96886caeb6389fef.tar.gz | |
Detect ld.so and libc.so version inconsistency during startup
The files NEWS, include/link.h, and sysdeps/generic/ldsodefs.h
contribute to the version fingerprint used for detection. The
fingerprint can be further refined using the --with-extra-version-id
configure argument.
_dl_call_libc_early_init is replaced with _dl_lookup_libc_early_init.
The new function is used store a pointer to libc.so's
__libc_early_init function in the libc_map_early_init member of the
ld.so namespace structure. This function pointer can then be called
directly, so the separate invocation function is no longer needed.
The versioned symbol lookup needs the symbol versioning data
structures, so the initialization of libc_map and libc_map_early_init
is now done from _dl_check_map_versions, after this information
becomes available. (_dl_map_object_from_fd does not set this up
in time, so the initialization code had to be moved from there.)
This means that the separate initialization code can be removed from
dl_main because _dl_check_map_versions covers all maps, including
the initial executable loaded by the kernel. The lookup still happens
before relocation and the invocation of IFUNC resolvers, so IFUNC
resolvers are protected from ABI mismatch.
The __libc_early_init function pointer is not protected because
so little code runs between the pointer write and the invocation
(only dynamic linker code and IFUNC resolvers).
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'INSTALL')
| -rw-r--r-- | INSTALL | 10 |
1 files changed, 10 insertions, 0 deletions
@@ -120,6 +120,16 @@ if 'CFLAGS' is specified it must enable optimization. For example: compiler flags which target a later instruction set architecture (ISA). +'--with-extra-version-id=STRING' + Use STRING as part of the fingerprint that is used by the dynamic + linker to detect an incompatible version of 'libc.so'. For + example, STRING could be the full package version and release + string used by a distribution build of the GNU C Library. This + way, concurrent process creation during a package update will fail + with an error message, _error while loading shared libraries: + /lib64/libc.so.6: ld.so/libc.so mismatch detected (upgrade in + progress?)_, rather than crashing mysteriously. + '--with-timeoutfactor=NUM' Specify an integer NUM to scale the timeout of test programs. This factor can be changed at run time using 'TIMEOUTFACTOR' environment |