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Mark Wielaard
77482c4bf6
This fixes an obscure SIGBUS error when using ELF_C_WRITE_MMAP on an ELF file that needs extending when the underlying file system is (nearly) full. Use posix_fallocate to make sure the file content is really there. Using ftruncate might mean the file is extended, but space isn't allocated yet. This might cause a SIGBUS once we write into the mmapped space and the disk is full. Using fallocate might fail on some file systems. posix_fallocate is required to extend the file and allocate enough space even if the underlying filesystem would normally return EOPNOTSUPP or the kernel doesn't implement the fallocate syscall. Also posix_fallocate has been in glibc since 2.1.94, while support for fallocate was only added in 2.10 and kernel 2.6.23. Signed-off-by: Mark Wielaard <mjw@redhat.com>
Fundamental design decision: - the sizes of external and internal types are assumed to be the same. This leaves byte ordering aside. While assuming this the code can be greatly simplified and speed increases. Since no change violating this assumption is in sight this is believed to be a worthwhile optimization. - the ABI of the backend modules is not guaranteed. Really, no guarantee whatsoever. We are enforcing this in the code. The modules and their users must match. No third-party EBL module are supported or allowed. The only reason there are separate modules is to not have the code for all architectures in all the binaries. - although the public libraries (libasm, libdw) have a stable API and are backwards ABI compatible they, and the elfutils tools, do depend on each others internals, and on internals of libelf to provide their interfaces. So they should always be upgraded in lockstep when packaging the tools and libraries separately. For one example of how to do that, see the config/elfutils.spec.