Make ./snabb binary more portable #359
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This will enable us to release Snabb Switch as a single executable file for any modern Linux/x86_64. ./snabb will link with any GLIBC version >= 2.7 (released 2007). This makes the binary linker-compatible with older Linux distributions such as Ubuntu 10.04 and CentOS 6. Tested when built on Ubuntu 14.04. Building on other distributions may yield different results, but a selftest script is included to catch that. (There may be other compatibility issues with older kernels and CPUs. This only takes care of the dynamic linking.)
Detect when compiling an assembler file and suppress the contents of the header file. (It only compiles as C.)
Print any symbols that depend on GLIBC > 2.7 and error unless there are none.
lukego
changed the title
lukego
added a commit
that referenced
this pull request
Feb 20, 2015
Make ./snabb binary more portable
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Prepare dynamic linking so that
./snabbis compatible with all GLIBC versions >= 2.7. This enables us to release Snabb Switch as a single executable file for any modern Linux/x86_64.Tested when built on Ubuntu 14.04. Building with newer versions of GLIBC can potentially break backwards compatibility. A
selftest.shscript is included to detect this.Makefile now forces GCC to always include the file
gcc-preinclude.h. This file can contain.symverdirectives to break dependencies on new GLIBC versions.There is currently one such directive forcing
memcpyto bind to the GLIBC 2.2.5 symbol instead of GLIBC 2.14. (This is because GLIBC made a semi-backwards-incompatible change tomemcpyin version 2.14.) Loosely speaking, this has the side-effect of forcingmemcpyto act likememmovei.e. to be safe for overlapping memory regions. This is not expected to have a significant performance impact, although that is not impossible. See long question to the GLIBC mailing list about this (unanswered).